ALBERT

Description: In den vergangenen zwei Jahren hat sich die Welt verändert und vermehrt beherrschen Krisen das Bild. Jahrzehntelange Gewissheiten gelten nicht mehr, Risiken und Unsicherheiten nehmen zu, die Herausforderungen werden immer komplexer und erfordern gleichzeitig immer schnelleres und konsequenteres Handeln.

Description: Seitdem Einweg-Plastikartikel wie Kunststofftüten und Strohhalme verboten wurden, sind Straßen und Strände sauberer geworden. Zudem wurde auch die öffentliche Diskussion über nachhaltigen Konsum intensiviert. Die Gesamtmenge an Kunststoff-Abfällen ließ sich mit "Plastikverboten" hingegen nicht signifikant reduzieren. Zu diesem Ergebnis kommt der vorliegende Polyproblem-Report der gemeinnützigen Röchling Stiftung und des Beratungshauses Wider Sense in Zusammenarbeit mit dem Wuppertal Institut. Die Autor*innen haben die Wirkung staatlicher Verbote von Einweg-Plastikprodukten unter die Lupe genommen und die Erfahrungen aus Deutschland, Kenia und Kalifornien analysiert.

Description: Within the Shaping Digitalisation project, we aim to highlight and discuss the opportunities that digitalisation can bring to Germany. In particular, we are discussing three stand-out areas where action is most needed to achieve ecological transformation: mobility, the circular economy, and agriculture and food. This report addresses the second area in need of action. Up until now, discussions on the circular economy have been limited to recycling and the re-use of materials. We must expand the scope of these discussions to include new, resource-efficient business models and the comprehensive transformation of value chains and industrial structures. Our analysis has found that digitalisation is indispensable for this transformation if used properly. We hope this report will provide the impetus needed to kick-start a climate- and resource-friendly industrial transformation in Germany. Here, we have incorporated the findings of our interdisciplinary workshop on "Shaping the Digital-Ecological Industrial Transformation - Business Models and Political Framework Conditions for Climate and Resource Protection" that was attended by experts from international research institutes, civil organizations, public authorities, and private companies.

Description: The introduction of a Digital Product Passport (DPP) is an opportunity to create a system that can store and share all relevant information throughout a product's life cycle. This would provide industry stakeholders, businesses, public authorities and consumers with a better understanding of the materials used in the product as well as their embodied environmental impact. With the COVID-19 pandemic, the Russian invasion of Ukraine and the cost-of-living crisis, now is a critical moment to transform our economic and business models, while also addressing the huge scale of material emissions. DPPs can be a pivotal policy instrument in this goal. Furthermore, DPPs can accelerate the twin green and digital transitions as part of EU efforts to deliver positive climate action and sustainable economies. In 2020, the European Commission (EC) adopted a new Circular Economy Action Plan (CEAP), which emphasised the need for circular economy initiatives to consider the entire life cycle of products, from the production of basic materials to end-of-life disposal. The Circular Economy Package published in March 2022 includes a proposal for an Ecodesign for Sustainable Products Regulation (ESPR), which builds upon the Ecodesign Directive that covers energy-related products. A DPP will form a key regulatory element of the ESPR by enhancing the traceability of products and their components. This will provide consumers and manufacturers with the information needed to make better informed choices by taking their environmental impact into consideration. As discussed in the report, there is widespread agreement amongst business leaders that a well-designed DPP could have both short- and longer-term benefits, improving access to reliable and comparable product sustainability information for businesses, consumers and policymakers. A well-designed DPP can unify information, making it more readily accessible to all actors in the supply chain. This will support businesses to ensure an effective transformation towards a decarbonised industry. It could also create incentives for companies to make their products more sustainable, as improving access to reliable and consistent information across supply chains will make it easier for customers to make comparisons.

Description: Die Dekarbonisierung der Mietwohnungsbestände ist zwingende Voraussetzung für die Einhaltung deutscher Klimaschutzziele. Hierzu ist eine schnelle und deutliche Verbesserung der Energieeffizienz unabdinglich. Aber: funktioniert der Markt für Energieeffizienz bei Mietwohnungen? Eine empirische Untersuchung auf dem Wuppertaler Mietwohnungsmarkt gibt Antworten darauf. Um die Sanierungsrate signifikant zu steigern, etwa durch eine höhere Zahlungsbereitschaft für Energieeffizienz, braucht es sowohl für Vermieter als auch für Mieter verbesserte Rahmenbedingungen.

Description: A main goal of this study - which also functions as deliverable 210078-D07 of the Circular Economy Beacons (CEB) project - is to evaluate currently available frameworks that measure and operationalise Circular Economy (CE), with a particular focus on the urban context. The regional focus lies on the Western Balkan region, which is at the centre of the project. Such "Urban Circularity Hotspot Frameworks" (UCHF) aim at providing decision support for policy makers, companies, citizens etc. regarding the transition to CE within cities. Based on the analysis of different frameworks, suggestions are derived regarding UCHF suitable for the specific characteristics of Western Balkan municipalities, i.e. a Circular Economy Beacons Urban Circularity Hotspot Framework (CEB-UCHF) ready for short-term implementation.

Description: Circular economy seems a vital enabler for sustainable use of natural resources which is also important for achieving the 2030 agenda for sustainable development goals. Therefore, a special session addressing issues of "sustainable solutions and remarkable practices in circular economy focusing materials downstream" was held at the 16th International Conference on Waste Management and Technology, where researchers and attendees worldwide were convened to share their experiences and visions. Presentations focusing on many key points such as new strategies, innovative technologies, management methods, and practical cases were discussed during the session. Accordingly, this article compiled all these distinctive presentations and gave insights into the pathway of circular economy towards the sustainable development goals. We summarized that the transition to circular economy can keep the value of resources and products at a high level and minimize waste production; the focus of governmental policies and plans with the involvement of public-private-partnership on 3Rs (reduce, reuse, and recycle) helps to improve the use of natural resources and take a step ahead to approach or achieve the sustainability.

Description: In Germany, the number of renewable energy prosumers has increased rapidly since 2000. However, the development of prosumers has faced and will continue to face various economic, social, and technological challenges, which have triggered the emergence of a number of innovative business models (BM). This paper enriches the empirical basis for prosumer-oriented BMs by investigating two BM innovations in Germany (P2P electricity trading and aggregation of small-size prosumers) drawing on business model and socio-technical transition theories. A mix of qualitative data collection methods, including document analysis and semi-structured expert interviews, was applied. We found that while both BMs can potentially address the challenges associated with renewable energy prosumer development in Germany, small-scale prosumers’ participation in both BMs has been limited so far. We identified various internal and external drivers and barriers for scaling up these BMs for prosumer development in Germany. Despite these barriers, both aggregation and centralized P2P targeting prosumers may potentially be also taken up by incumbent market actors such as utilities. Decentralized P2P on the other hand still faces significant internal and external barriers for upscaling. Based on the analysis, the paper provides policy recommendations with respect to the identified drivers and barriers. From a theoretical perspective, our findings provide further evidence to challenge the dichotomous understanding of niche actors and incumbents, the latter of which are often theorized to be resistant to radical innovations.

Description: How do recent changes in consumption in the wake of the COVID-19 pandemic affect the avoidance of packaging waste? How can an increase in packaging waste be countered and the previous trend towards unpackaged and reusable solutions be revived and promoted? To tackle these questions, we use a systemic approach that regards packaging as a network of interrelated interests of industry (manufacturing and logistics), trade (retail and catering), consumers and the waste management sector. To analyse this network, we applied three methods. First, we analysed secondary sources such as surveys. Second, we conducted semi-structured interviews with seven actors from industry, consumer education and waste management in May and June 2020. Third, we used the questions from the interview guideline to do an online survey among representatives of the public waste management industry.

Description: Die GLS Bank finanziert gezielt nachhaltige Projekte und Unternehmen in den Bereichen erneuerbare Energien, nachhaltige Wirtschaft, Ernährung, Wohnen, Bildung & Kultur, Soziales & Gesundheit. Eine zentrale Herausforderung ist es, die Nachhaltigkeitswirkung der Finanz- und Anlagestrategie robust zu quantifizieren und transparent darzustellen. Die GLS Bank hat sich zum Ziel gesetzt, die hierfür notwendigen Methoden und Daten zur Bewertung der Nachhaltigkeitswirkungen ihres Finanz- und Anlagenportfolios schrittweise weiterzuentwickeln, um eine richtungssichere Portfoliosteuerung und Kundenbetreuung zu unterstützen. Ziel des Projektes ist zunächst, das Emissionsgeschehen der finanzierten Wertschöpfungskette abzubilden (Scope 3), aber auch die eingesparten Emissionen als einen Beitrag zum Klimaschutz zu bewerten (Scope 4). Es werden die Scope 3 Emissionen der GLS Bank in den folgenden Finanz- und Anlagebereichen für das Berichtsjahr 2019 bilanziert: 1. Aktien- und Klimafonds; 2. Kredite; 3. Unternehmensbeteiligung. Scope 4 Emissionen werden in Form vermiedener Emissionen (Carbon Handprint) dabei ausschließlich für Bereiche bilanziert, in denen THG-Reduktionspotentiale richtungssicher abgeschätzt werden können. Im vorliegenden Bericht wird der Untersuchungsrahmen, die vom Wuppertal Institut entwickelte Methodik sowie Lösungsstrategien für die Überbrückung geringer Datenqualität/-verfügbarkeit beschrieben. Die Robustheit der Ergebnisse wird durch Prüfungsmethoden reflektiert und dem Leser somit eine Interpretationsunterstützung gegeben. In einem Ausblick werden Weiterentwicklungsbedarfe und -möglichkeiten skizziert, um schrittweise eine zunehmend robuste und wissenschaftliche fundierte Methodik und Datengrundlage zur Bewertung der Klimawirkung sowie weiterer Nachhaltigkeitswirkungen des Finanz- und Anlageportfolios der GLS Bank in Zusammenarbeit mit relevanten Stakeholdern zu etablieren.

Description: Damit sich die weltweit zunehmend ambitionierten Klimaschutzziele erreichen lassen, müssen auch im Industriesektor weitgehende Emissionsreduktionen innerhalb weniger Jahrzehnte realisiert werden. Expertinnen und Experten sind sich einig, dass dies nicht ohne den Umstieg von fossilen auf erneuerbare Energieträger und Rohmaterialien - sogenannte Feedstocks - umsetzbar ist. Im Zuge der verstärkten Nutzung dieser grünen Energieträger ist denkbar, dass sich deren Verfügbarkeit und Kosten zu immer wichtigeren Standortfaktoren für die Produktion industrieller Güter entwickeln werden. Dies könnte dazu führen, dass zukünftig Standorte mit kostengünstiger Verfügbarkeit von erneuerbaren Energien attraktiver gegenüber anderen Standorten werden und es dann zu Standortverlagerungen kommt - insbesondere im Bereich der energieintensiven Industrie. In dem vorliegenden Artikel greifen die Autoren diese möglichen Verlagerungen industrieller Produktion auf. In diesem Zusammenhang führen sie auch den Begriff "Renewables Pull" ein. Die in bestimmten Regionen der Welt kostengünstig und in großen Mengen verfügbaren erneuerbaren Energien könnten nach Ansicht der Autoren künftig eine Sogwirkung auslösen und bestimmte Teile der industriellen Produktion anziehen - auch Pull-Effekt genannt.

Description: The transition from today's "take, make, waste" economic paradigm to a circular economy requires a joint effort from actors on all levels: governments, business, and civil society. While companies are among the drivers of the circular transformation, they find it hard to achieve a circular economy on their own. Hence, cross-industry collaboration is one of the imperatives for scaling a circular economy. Against this background, econsense, together with Accenture and the Wuppertal Institute, launched its study "Germany's Transition to a Circular Economy - How to Unlock the Potential of Cross-Industry Collaboration". Based on a survey and expert interviews within the econsense community, the study finds that companies are yet to unlock the full potential of cross-industry collaboration. While two thirds of analysed industry collaborations have a high potential for scaling the circular economy, only 43 per cent of those already show a high degree of interaction. The study provides concrete guidance for companies to get started with circularity and identify the right partners for cross-industry collaboration. Specifically, the report recommends companies: 1) Understand what circularity is about and map it on their own operations and processes. 2) Understand the different circular business models and identify the ones relevant to each business. 3) Discover areas where collaboration can help to create the needed foundation and to execute circular actions.

Description: Digitalisation is taking place at a fast pace in all European countries and it is transforming the economies, societies, communication, jobs and the necessary skills for the workplace and everyday life. The Covid-19 pandemic is also accelerating digitalisation at many levels. To address the great challenges resulting from this, the European Commission has launched the Green Deal, a long-term transformation strategy towards an innovative and sustainable society. Three important initiatives under the Green Deal are the New Circular Economy Action Plan, the Biodiversity Strategy for 2030 and the Zero Pollution Action Plan. The various strategies and action plans draw up a large portfolio of measures, instruments and milestones that are always linked to digital technologies. Ideally, these are eco-innovative and sustainable and contribute to improving living conditions in Europe. The EIO Biennial Report 2020, which looks at a different topic every two years, considers digitalisation a major opportunity to accelerate the transition to a circular Europe. In the current report, the authors provide an overview of eco-innovation trends, illustrated by digital technology and policy practices that can further drive the circular economy.

Description: Auf dem Weg zu einer ressourceneffizienten Gesellschaft bedarf es richtiger Rahmenbedingungen, Informationen und Handlungsalternativen. Eine Möglichkeit, diese Voraussetzungen zu schaffen, ist ein kommunales Zero-Waste-Konzept. Zero Waste lässt sich übersetzen mit "Null Abfall, null Verschwendung" und verfolgt das Ziel, möglichst wenig Abfall zu produzieren sowie effizient und sparsam mit Ressourcen umzugehen. Ein solches Konzept wie in Kiel ist die Basis für eine Zertifizierung als Zero Waste City, eine Auszeichnung, die der europäische Verein Zero Waste Europe vergibt. 2007 wurde die italienische Gemeinde Capannori zur ersten Zero Waste City in Europa erklärt, seitdem sind knapp 400 europäische Gemeinden dieser Bewegung gefolgt.

Description: Öffentliche Mittel für die Unterstützung von Unternehmen sollten bestenfalls so eingesetzt werden, dass sie eine möglichst große, nachhaltige Wirkung haben und mit einem gesellschaftlichen Nutzen verbunden sind. Das kann unmittelbar erfolgen, in dem die konkrete Förderung an bestimmte Vorgaben gebunden wird, wie etwa den Ausbau von zukunftsfähigen Infrastrukturen. Es besteht jedoch auch die Möglichkeit, die Risikoabsicherung von Unternehmen - beispielsweise über Bürgschaften oder andere geeignete Finanzierungskonditionen - an der Nachhaltigkeitsperformance der Unternehmen auszurichten. Der vorliegende vierstufige Leitfaden, den der WWF Deutschland und das Wuppertal Institut entwickelt haben, dient als Grundlage für die zielorientiertere Vergabe von Mitteln und deren praktische Umsetzung. Er baut auf der von der Europäischen Union entwickelten "Taxonomie" für nachhaltige Investitionen auf. Darin enthalten sind Grenzwerte, welche die Nachhaltigkeitsperformance wirtschaftlicher Aktivitäten definieren. Auf diese Weise lässt sich filtern, ob ein wirtschaftliches Vorhaben zukunftsfähig ist. Hierbei unterstützt der "Entscheidungsbaum" des Leitfadens die Anwendung der EU-Taxonomie als Regelwerk.

Description: Diese Kurzstudie ist Teil des Verbundvorhabens "Circular Economy als Innovationsmotor für eine klimaneutrale und ressourceneffiziente Wirtschaft (CEWI)" der Stiftung 2°, dem WWF Deutschland und dem Wuppertal Institut und hat zum Ziel, die Potenziale des Gebäudesektors und der dazugehörigen Wertschöpfung im Hinblick auf die Umsetzung von zirkulären Ansätzen zu analysieren und den Beitrag zur Ressourceneinsparung und dem Klimaschutz zu bewerten. Das Ergebnis dieser Kurzstudie leitet sich aus einem intensiven Bewertungsprozess verschiedener Maßnahmen-Cluster ab und besteht aus sechs Handlungsfeldern, die ein Potenzial für den Ausbau von Klimaneutralität und Ressourceneffizienz im Gebäudesektor aufweisen. Diese Handlungsfelder bilden die Grundlage für den weiteren Projektverlauf von CEWI, in dem Industrieakteure in Workshops gemeinsam Pilotprojekte modellieren werden.

Description: Diese Kurzstudie ist Teil des Verbundvorhabens "Circular Economy als Innovationsmotor für eine klimaneutrale und ressourceneffiziente Wirtschaft (CEWI)" der Stiftung 2°, dem WWF Deutschland und dem Wuppertal Institut und hat zum Ziel, die Potenziale des Automobilsektors und der dazugehörigen Wertschöpfung im Hinblick auf die Umsetzung von zirkulären Ansätzen zu analysieren und den Beitrag zur Ressourceneinsparung und dem Klimaschutz zu bewerten. Das Ergebnis dieser Kurzstudie leitet sich aus einem intensiven Bewertungsprozess verschiedener Maßnahmen-Cluster ab und besteht aus sechs Handlungsfeldern, die ein Potenzial für den Ausbau von Klimaneutralität und Ressourceneffizienz im Automobilsektor aufweisen. Diese Handlungsfelder bilden die Grundlage für den weiteren Projektverlauf von CEWI, in dem Akteure aus der Praxis in Workshops gemeinsam Pilotprojekte modellieren werden.

Description: Die Wirtschaftsförderung Region Stuttgart GmbH (WRS) unterstützt die Transformation der Region Stuttgart in Richtung Nachhaltigkeit und sieht die Bioökonomie als eine wichtige Strategie zu diesem Zweck. Die WRS hat das Wuppertal Institut mit dieser Kurzstudie mit dem Fokus auf die industrielle Bioökonomie beauftragt, um eine Informationsgrundlage für die Spezifikation weiterer Aktivitäten der WRS im Kontext der Bioökonomie zu schaffen. Die Studie gibt einen Überblick über definitorische Ansätze und Diskurslinien der Bioökonomie. Sie fasst Einschätzungen des deutschen Bioökonomierates zu Marktpotenzialen der Bioökonomie in verschiedenen Branchen zusammen, die u.a. für Automobil, Biotechnologie und IKT als gut eingeschätzt werden. Anschließend umreißt die Studie die Innovationsansätze Biomimikry und Biointelligenz. Für den Ansatz Biointelligenz zur biologischen Transformation der industriellen Wertschöpfung werden die in Studien von Dritten identifizierten Marktpotenziale der Biointelligenz zusammengefasst, u.a. in den Bereichen Unterstützungssysteme, Produktionssysteme/-technologien und Baumaterialien. Darüber hinaus stellt die Studie Schnittstellen relevanter Landesstrategien in Baden-Württemberg zu Bioökonomiethemen dar, die synergetisch genutzt werden könnten. Ergänzend gibt die Studie einen Überblick über die Akteurslandschaft in Baden-Württemberg. Der Überblick basiert insbesondere auf dem Bioökonomie Kompetenzatlas wissenschaftlicher Akteure, der von der Landeskoordinierungsstelle an der Universität Hohenheim herausgegeben wird, sowie einer Akteursanalyse aus dem Projekt "Bioökonomie in Baden-Württemberg", das am KIT durch das ITAS durchgeführt wurde und durch die BIOPRO Baden-Württemberg GmbH unterstützt wurde. Auf Basis dieser Informationssammlung entwirft die Studie weiterführende Fragen in Bezug auf mögliche weitere Aktivitäten der WRS im Kontext der Bioökonomie, u.a. die mögliche Nutzung von Innovationsansätzen aus dem Bereich der Living Lab und Reallaborforschung.

Description: Two thirds of today's world trade is based on global value chains and supply networks. Purely regional supply chains have become less important in recent decades. The effects of these globalised structures are manifold. On the one hand, they promote employment and generate prosperity. On the other hand, they are beset by extreme social, ecological and economic imbalances. The COVID-19 pandemic has demonstrated the fragility of existing supply chain systems. The lockdown continues to disrupt complex supply chains and many problems of existing production and consumption continue to worsen. COVID-19 is one example of the crises that can shake globally networked supply chains in the short term. Other crises, such as climate change, develop more insidiously and are less immediately recognisable. Different as they are, such crises have one thing in common: they highlight the vulnerability of global social and economic structures and illustrate the impact of global trade on the regions and people of the world. This is precisely where global sustainability strategy comes in - it aims to fundamentally reduce differences and inequalities in opportunities and quality of life. The COVID-19 pandemic has forced the entire world into upheaval, creating an opportunity to make sustainability a central political resilience strategy. In the wake of the Corona pandemic, the discussion about resilient communities has flared up. In order to guarantee supply in the face of such crises, these should be more strongly regional and circular in their economic approach and global and sustainable in their perspective. The aim should be sustainable, transparent, non-exploitative supply chains that guarantee the security of supply to cover basic needs and public services despite sudden changes and crises. This discussion paper draws a future scenario of globally cooperative, circular regional economies that fundamentally reduce global inequalities in opportunities and quality of life, while at the same time permanently preserving the natural foundations of life.

Description: Immer mehr Unternehmen verkünden, klimaneutral sein zu wollen und zahlreiche Firmen bieten bereits klimaneutrale Produkte oder Dienstleistungen an: Von der klimaneutralen Paketzustellung bis zur Flugreise. Doch was bedeuten die Neutralitätsziele der Unternehmen genau? Ist das gesetzte Ziel ambitioniert? Und welche Rolle spielt Offsetting, also der Ankauf von Klimaschutzzertifikaten und deren Anrechnung auf das eigene Klimaschutzziel? Die hinter den verkündeten Zielen stehenden Ansätze sind häufig nur schwer nachvollziehbar. Vor diesem Hintergrund gibt der vorliegende Zukunftsimpuls zehn Empfehlungen für die Festlegung und Umsetzung von Neutralitätszielen. Die Autorinnen und Autoren sprechen sich dabei unter anderem für die Nutzung einer robusten Datenbasis als Grundlage für Neutralitätsziele aus, betonen die Bedeutung einer transparenten Kommunikation und zeigen auf, welche Rolle Offsetting spielen sollte. So sollten angekaufte Klimaschutz-Zertifikate einen möglichst begrenzten Beitrag zur Zielerfüllung leisen und ausschließlich zum Ausgleich von Emissionen genutzt werden, die nicht reduziert oder vermieden werden können. Insgesamt sollten Neutralitätsziele nicht zum alleinigen Kriterium für ambitionierten Klimaschutz von Unternehmen gemacht werden, sie stellen vielmehr ein Baustein einer weitaus umfassenderen unternehmerischen Klimaschutzstrategie dar.

Description: With increasing world population and an unsettling resource scarcity in the back, sustainble consumption has moved to the foreground of political, economical and social discussions. One major school-of-thought is Circular Economy (CE), an approach summarizing various sustainable consumption activites under one roof. However, quantitative studies on the consumer are rare, yet crucial for a transfer from linear to circular consumption. This dissertation adds to literature by providing pioneer insights into consumer behavior in CE as an overarching concept, instead limiting research on singular subconcepts. Namely, four consumer activities are studied: recycling, upcycling, renting and sharing. In order to identify relevant insights for both academics and practitioners in CE, the research question ("what drives participation in CE?") is broken down into sub-hypotheses, which are addressed by three empirical studies. Using the SOR-Model (adaption Belk 1975) as overarching logic, the three studies deal with (1) the consumer (and their motivation) and situational stimuli (both (2) offline and (3) online). Respectively, three data sets are consulted to assess the sub-hypotheses and to identify overarching insights on how to accelerate consumer participation in CE, The research methodology employed ranges from a structured equation model (SEM), a random allocation field experiment during Fashion Week in Berlin to a discrete-choice model with best-worst scaling. The dissertation succeeds in revealing that (1) different activities in CE can be summarized in one latent variable, proving CE as a wholesome concept in consumer-related activities; that (2) Trust has a leveraging effect on participation in CE activities. Further, Trust can be enhanced offline via face-to-face interaction and online via third-party online attributes.; and that (3) experience in CE activities affects perception of online attributes, implying the need for adapted measures when dealing with CE-unexperienced consumers as compared to consumers with prior experience in CE activities.

Description: Industrial demand response can play an important part in balancing the intermittent production from a growing share of renewable energies in electricity markets. This paper analyses the role of aggregators - intermediaries between participants and power markets - in facilitating industrial demand response. Based on the results from semi-structured interviews with German demand response aggregators, as well as a wider stakeholder online survey, we examine the role of aggregators in overcoming barriers to industrial demand response. We find that a central role for aggregators is to raise awareness for the potentials of demand response, as well as to support implementation by engaging key actors in industrial companies. Moreover, we develop a taxonomy that helps analyse how the different functional roles of aggregators create economic value. We find that there is considerable heterogeneity in the kind of services that aggregators offer, many of which do create significant economic value. However, some of the functional roles that aggregators currently fill may become obsolete once market barriers to demand response are reduced or knowledge on demand response becomes more diffused.

Description: The study sheds light on the background of the prevention of plastic waste from packaging and disposable products by explaining the need for action, the environmental impacts and risks to human health. Experiences of the members of the PREVENT Waste Alliance and their partners in the prevention of plastic waste by multi-actor partnerships are presented by means of 17 best practice examples. Finally, the study gives recommendations for the reduction of plastic waste and the further work of the PREVENT Waste Alliance. These include success factors for waste prevention, necessary next steps and conclusions regarding the necessary political framework conditions.

Description: Die beiden mächtigsten Energiekonzerne in Deutschland fusionieren wechselseitig ihre Geschäftsfelder. Das Ergebnis wird eine bisher nie dagewesene Marktbeherrschung im Energiesektor darstellen. Die beiden Autoren beleuchten den Deal und kritisieren die Untätigkeit sämtlicher Aufsichtsbehörden.

Description: Prepaid-Stromzähler sind in Deutschland noch selten, bieten jedoch zukünftig einen interessanten Markt. Vor allem kleinere Anbieter, aber auch erste Regionalversorger kombinieren die Megatrends Digitalisierung und Energiewende und kreieren daraus neue Dienstleistungen. Zusammen mit IT-Firmen entwickeln sie daraus neue Geschäftsideen, die auch hinsichtlich sozialer Aspekte hohen Anforderungen genügen. Der Rollout von Smart Metering-Lösungen eröffnet zukünftig noch größere Chancen, durch Echtzeit-Datenerfassung den Energieverbrauch und damit auch Einsparpotenziale transparent zu machen. Hochaufgelöste Daten ermöglichen innovative Dienstleistungen und bringen die Kundenbeziehung auf eine neue Ebene.

Description: Mehr als sechs Millionen Tonnen Kunststoffabfälle fallen in Deutschland jährlich an, nur etwas weniger als die Hälfte kann werk- und rohstofflich genutzt werden, der Rest wird verbrannt. Gerade gemischte Kunststoffarten erschweren das Recycling. Hier bietet sich das chemische Recycling (Pyrolyse) an. Bei diesem Verfahren werden die Stoffe durch hohe Temperaturen zersetzt und in kleinere Moleküle aufgespalten. Diese lassen sich im Sinne der Kreislaufwirtschaft in neue Kunststoffe oder chemische Grundstoffe überführen. Die Schätzungen gehen von bis zu zwei Millionen Tonnen Kunststoffabfall jährlich aus, der auf diese Weise wiederverwendet werden könnte. Das vorliegende Diskussionspapier zeigt, dass Pyrolyse von gemischten Kunststoffabfällen die chemische Industrie sowie die Abfallwirtschaft klimafreundlicher gestalten kann. Im Papier geht das Autorenteam auf die Potenziale und Entwicklungsperspektiven für Nordrhein-Westfalen ein mit dem Ziel, wissenschaftliche Grundlagen für Investitionsentscheidungen und Projektentwicklung im Sinne der Kreislaufwirtschaft zu schaffen.

Description: Die Emscher-Lippe Region ist seit vielen Jahren von einer intensiven wirtschaftlichen Transformation geprägt. Die fortschreitende De-Industrialisierung bzw. die Neuorientierung der Industrie nach dem Wegfall der Kohle- und Stahlindustrie stellt regionale Entscheidungsträger vor große Herausforderungen, wenn es darum geht, der hohen Arbeitslosenquote zu begegnen, Beschäftigungsquoten zu sichern, mit der prekären Finanzsituation in den kommunalen Haushalten umzugehen und den Wirtschaftsstandort zu stabilisieren und neu aufzustellen. Der Strukturwandel der Region ist mit Schließung der letzten Steinkohle-Zeche Ende 2018 nicht abgeschlossen, sondern geht mit dem Kohleausstieg im Energiesektor in eine zweite Phase. Dies sollte auch als Chance verstanden werden, den Wirtschaftsstandort Emscher-Lippe mit seinen energiereichen Industrien innovativ neu zu gestalten und die Region sowohl energetisch, als auch stofflich von der Nutzung fossiler Träger abzukoppeln. Eine wichtige Säule der regionalen Wirtschaftsförderung besteht darin, strategische Netzwerke und regionale Wertschöpfungsketten zu stärken, um die in der Region ansässigen (mittelständischen) Unternehmen zu unterstützen und den Strukturwandel innerhalb der dominierenden Industrien aus den Bereichen Energieerzeugung und chemischer Industrie zu begleiten. Die vorliegende Studie bereitet auf, welche Bedeutung die Wasserstoffwirtschaft in der Emscher-Lippe Region in diesem Zusammenhang derzeit spielt und zukünftig spielen könnte.

Description: Die Europäische Union (EU) hat erkannt, dass das Ziel der Klimaneutralität bis 2050 ein zentraler Innovations- und Wachstumsmotor für Industrie und Wirtschaft in der EU sein kann. Neben großen Chancen stellt dies die europäische Wirtschaft und überwiegend die besonders emissionsintensiven sowie im international starkem Wettbewerb stehenden Grundstoffindustrien auch vor erhebliche Herausforderungen. Eine integrierte Klima- und Industriestrategie ist für den Klimaschutz von zentraler Bedeutung, da auf die Produktion von Stahl, Zement, Grundstoffchemikalien, Glas, Papier und anderen Materialien in der EU und weltweit rund 20 Prozent der gesamten Treibhausgasemissionen entfallen. Auch in einer treibhausgasneutralen Zukunft kann auf diese Materialien nicht verzichten werden. Zugleich ist die emissionsfreie Herstellung der Materialien technologisch sowie mit Blick auf die dafür erforderlichen Infrastrukturen besonders herausfordernd. Dies gilt vor allem für die Frage woher die hohen benötigten Mengen an grüner Energie - insbesondere Strom und Wasserstoff - zu wettbewerbsfähigen Preisen kommen sollen. Analysen zeigen, dass trotz erheblicher Kosten bei der Prozessumstellung die Kosten der Transformation der Grundstoffindustrie für die Gesellschaft insgesamt tragbar sind. Denn bezogen auf die Endprodukte betragen die Mehrkosten meist nur wenige Prozentpunkte; die Preise von Rohstahl oder Zement dagegen würden sich zwischen einem Drittel und 100 Prozent verteuern. Da fast alle Grundstoffhersteller in starker Weltmarktkonkurrenz stehen, können sie die Investitionen in eine klimaneutrale Produktion und die benötigten Energieinfrastrukturen aber nicht ohne Unterstützung tragen. Das vorliegende Papier skizziert ein integriertes Klima-Industriepolitikpaket, das der EU ermöglichen kann, die bestehende technologische Führung in vielen dieser Industrien zielgerichtet zum Aufbau einer treibhausgasneutralen Grundstoffindustrie zu nutzen.

Description: Through the Surveyor 3 and 7, and Apollo 11-17 missions a knowledge of the mechanical properties of Lunar regolith were gained. These properties, including material cohesion, friction, in-situ density, grain-size distribution and shape, and porosity, were determined by indirect means of trenching, penetration, and vane shear testing. Several of these properties were shown to be significantly different from those of terrestrial soils, such as an interlocking cohesion and tensile strength formed in the absence of moisture and particle cementation. To characterize the strength and deformation properties of Lunar regolith experiments have been conducted on a lunar soil simulant at various initial densities, fabric arrangements, and composition. These experiments included conventional triaxial compression and extension, direct tension, and combined tension-shear. Experiments have been conducted at low levels of effective confining stress. External conditions such as membrane induced confining stresses, end platten friction and material self weight have been shown to have a dramatic effect on the strength properties at low levels of confining stress. The solution has been to treat these external conditions and the specimen as a full-fledged boundary value problem rather than the idealized elemental cube of mechanics. Centrifuge modeling allows for the study of Lunar soil-structure interaction problems. In recent years centrifuge modeling has become an important tool for modeling processes that are dominated by gravity and for verifying analysis procedures and studying deformation and failure modes. Centrifuge modeling is well established for terrestrial enginering and applies equally as well to Lunar engineering. A brief review of the experiments is presented in graphic and outline form.

Description: Nonthermal radio emissions from earth, Jupiter, Saturn, and Uranus are reviewed. The dominant source of emission at each planet appears to be AKR-like auroral emission in the X-mode. O-mode emissions are substantially responsible. There is a remarkably constant scaling factor relating the total solar wind input power into each planetary system and the AKR-like auroral emissions.

Description: This article presents the results of a fit of a model of the Martian satellite orbits to earthbased and spacecraft-based observations. An assessment of the orbit accuracies is given and the orbits are compared with those obtained by previous investigators.

Description: The petrology and chronology of early lunar crust is examined using the least equivocal of the available petrographic and age data on lunar rock samples, and the possible processes which produced the lunar crust are discussed. The results suggest that the lunar anorthositic crust was formed by about 120 Ma after the primary accretion of the moon at 4.56 Ga. At least some members of the diverse Mg-suites of rocks, such as norites, troctolites, and dunites, crystallized within a very few 100s of Ma after 4.56 Ga. A trace-element-rich material (KREEP) was formed by about 4.3 Ga ago, and this residue was subsequently reworked in melting and impact processes such that most samples which contain it have ages around 3.9-4.0 Ga. The findings also suggest that the onset of ferrous mare basalt volcanism began about 4.33 Ga, much earlier than was once assumed, and was still in process before the end of the most intense period of bombardment (3.9-4.0 Ga ago).

Description: The findings made by the Voyager 2 Neptune encounter are reviewed. Data on the bowshock, magnetic field, magnetosphere, rings, plasma sheet, aurora, moons, and dust of Neptune are discussed. Findings made concerning Triton are summarized.

Description: The composition of lunar regolith and its attendant properties are discussed. Tables are provided listing lunar minerals, the abundance of plagioclase feldspar, pyroxene, olivine, and ilmenite in lunar materials, typical compositions of common lunar minerals, and cumulative grain-size distribution for a large number of lunar soils. Also provided are charts on the chemistry of breccias, the chemistry of lunar glass, and the comparative chemistry of surface soils for the Apollo sites. Lunar agglutinates, constructional particles made of lithic, mineral, and glass fragments welded together by a glassy matrix containing extremely fine-grained metallic iron and formed by micrometeoric impacts at the lunar surface, are discussed. Crystalline, igneous rock fragments, breccias, and lunar glass are examined. Volatiles implanted in lunar materials and regolith maturity are also addressed.

Description: Theoretical models of planetary-ring dynamics are discussed in a detailed analytical review and illustrated with graphs and diagrams. The streamline concept is introduced, and the phenomena associated with the transport of angular momentum are described. Particular attention is then given to (1) broad rings like those of Saturn (shepherding, density-wave excitation, gaps, bending-wave excitation, multiringlet structures, inner-edge shepherding, and the possibility of polar rings around Neptune), (2) narrow rings like those of Uranus (shepherding, ring shapes, and a self-gravity model of rigid precession), and (3) ring arcs like those seen in stellar-occultation observations of Neptune.

Description: Images of Neptune obtained by the narrow-angle camera of the Voyager 2 spacecraft reveal large-scale cloud features that persist for several months or longer. The features' periods of rotation about the planetary axis range from 15.8 to 18.4 hours. The atmosphere equatorward of -53 deg rotates with periods longer than the 16.05-hour period deduced from Voyager's planetary radio astronomy experiment (presumably the planet's internal rotation period). The wind speeds computed with respect to this radio period range from 20 meters per second eastward to 325 meters per second westward. Thus, the cloud-top wind speeds are roughly the same for all the planets ranging from Venus to Neptune, even though the solar energy inputs to the atmospheres vary by a factor of 1000.

Description: The theory of turbulent plumes maintained above steady line sources of buoyancy is worked out in detail within the limitations of Taylor's entrainment assumption. It is applied to the structure of a pure plume injected into a stably stratified atmosphere. Volcanic basalt eruptions that develop from long, narrow vents create line source plumes, which rise well above the magmatic fire fountains playing near the ground level. The eruption of Laki in 1783 may provide an example of this style of eruption. Flood basalts are more ancient examples. Evidence of enormous fissure eruptions that occurred in the past on Mars and Venus also exists. Owing to the different properties of the atmospheres on these two planets from those on the earth, heights of line source plumes are expected to vary in the ratios 1:6:0.6 (earth:Mars:Venus). It is very unlikely that the observed increase of sulfur dioxide above the Venusian cloud deck in 1978 could have been due to a line source volcanic eruption, even if it had been a flood basalt eruption.

Description: An analytical and numerical study of the stability of polar rings around Neptune is presented. The stability proofs are based on various methods used to study gas disks in galaxies. It is shown that stable polar rings can exist despite energy dissipation by collisions between particles. Also, four equilibrium orientations which pass nearly over the pole of Neptune are found, two of which are stable in the presence of dissipation.

Description: Issues related to the establishment of lunar observatories are briefly addressed. The advantages of placing an observatory in a crater at one of the poles, where permanent darkness exists, are pointed out, and the methods required to emplace and operate such an observatory are considered. Planning for the installation of the first set of observatory instruments is discussed.

Description: The phenomena of the Saturn system discovered by the Voyager missions are addressed. The characteristics of the rings, including grooves, spikes, and warps, are described, and the discovery of bombarded rings and young rings is discussed. The unique and unexplained properties of Enceladus are summarized, and the possibility that some moons of Saturn have been reassembled is addressed. The interaction of moons with the rings is examined, and the possibility that Titan's atmosphere may contain complex molecules that are the precursors of life is considered.

Description: Spectral data from earth observations have indicated the presence of N2 and CH4 on Triton. This paper outlines the use of the 1-D radiative-convective model developed for Titan to calculate the current pressure of N2 and CH4 on Triton. The production of haze material is obtained by scaling down from the Titan value. Results and predictions for the Voyager Triton encounter are as follows: A N2-CH4 atmosphere on Triton is thermodynamically self consistent and would have a surface pressure of approximately 50 millibar; due to the chemically produced haze, Triton has a hot atmosphere with a temperature of approximately 130 K; Triton's troposphere is a region of saturation of the major constituent of the atmosphere, N2.

Description: The process by which ambient gases can be implanted into silicates by shocks was investigated by analyzing the noble-gas content of several experimentally and naturally shocked silicate samples. The retentivity of shock-implanted gas during stepwise heating in the laboratory was defined in terms of two parameters, namely, the activation energy for diffusion and the extraction temperature at which 50 percent of the gas is released, both of which correlate with the shock pressure. The experiments indicate that, with increasing shock pressure, gas implantation occurs through an increasing production of microcracks/defects in the silicate lattice. The degree of annealing of these defects control the degree of diffusive loss of implanted gas.

Description: The long-term modulation of Saturn's nonthermal radio emission in the kilometric wavelength range has been studied based upon data obtained by Voyagers 1 and 2. A comparison of the ballistic and hydrodynamic propagation of solar wind features from the spacecraft to Saturn allows the uncertainty inherent in the projection to be determined. The results confirm the previous suggestion that momentum, ram pressure, and kinetic energy flux are the primary solar wind parameters that drive the nonthermal radio emission. It is suggested that, under certain conditions and for limited periods of time, the magnetic properties and time derivatives of the solar wind have increased importance.

Description: It has been observed from the plasma experiments on the Pioneer Venus Orbiter that the altitude of the upper boundary of the ionosphere decreases in response to increasing solar wind dynamic pressure. However, at pressures above about 2.5 x 10 to the -8th dynes/sq cm, the further decrease in the ionopause height is rather small. Following the model of Cloutier et al. (1969), it is suggested that during high solar wind conditions, when the ionopause is formed at lower altitudes, the solar wind induces vertical and horizontal flows which sweep away the ionospheric plasma that is produced locally by photoionization. As a result, a disturbed photodynamical ionosphere is formed which has the scale height of the ionizable neutral constituent. It is shown that such a photodynamical ionosphere is observed at the subsolar ionopause under these conditions. As a consequence of this interaction, the ionopause altitude is observed to follow the small-scale height of the ionizable species, atomic oxygen, showing only small changes with solar wind pressure.

Description: Asteroids appear in light of telescopic and meteority studies to be the most accessible repositories of early solar system history available. In the cooler regions of the outer asteroid belt, apparently unaffected by severe heating, the C, P, and D populations appear to harbor significant inventories of volatiles; the larger primordial belt population may have had an even greater percentage of volatile-rich, low-albedo asteroids, constituting a potent asteroid for veneering early terrestrial planet atmospheres. The volatile-rich asteroids contain carbon, structurally bound and adsorbed water, as well as remnants of interstellar material predating the solar system.

Description: The development and implementation of the Voyager missions are reviewed. The interplanetary missions preceding Voyager are discussed, focusing on the technological development leading up to the Voyager spacecraft. The main results from Voyager observations of Jupiter, Saturn, and Uranus are outlined. Also, consideration is given to the prospects for observations of Neptune.

Description: Isotopic analysis of nesquehonite recovered from the surface of the LEW 85320 H5 ordinary chondrite shows that the delta C-13 and delta O-18 values of the two generations of bicarbonate (Antarctic and Texas) are different: delta C-13 = + 7.9 per mil and + 4.2 per mil; delta O-18 = + 17.9 per mil and + 12.1 per mil, respectively. Carbon isotopic compositions are consistent with equilibrium formation from atmospheric carbon dioxide at - 2 + or - 4 C (Antarctic) and + 16 + or - 4 C (Texas). Oxygen isotopic data imply that the water required for nesquehonite precipitation was derived from atmospheric water vapor or glacial meltwater which had locally exchanged with silicates, either in the meteorite or in underlying bedrock. Although carbonates with similar delta C-13 values have been identified in the SNC meteorites EETA 79001 and Nakhla, petrographic and temperature constraints argue against their simply being terrestrial weathering products.

Description: A primary concern in the formation of a multinational Mars-exploration program is that of technology transfer, which would be most acute in the U.S./U.S.S.R. case but would exist in lesser degree among other nations. Another concern is that of management-complexity, which could inflate total costs and substantially counteract the anticipated benefits of spreading program costs among a number of nations. It is presently suggested that these problems can be substantially reduced by having each nation become responsible for one (or more) complete flight system. Each nation's role in mission operations must be clear, and the cleanliness of interfaces among flight systems must carry over into mission operations.

Description: Observations of the stratospheric IR emission structure on Saturn are presented. The high-spatial-resolution global images show a variety of new features, including a narrow equatorial belt of enhanced emission at 7.8 micron, a prominent symmetrical north polar hotspot at all three wavelengths, and a midlatitude structure which is asymmetrically brightened at the east limb. The results confirm the polar brightening and reversal in position predicted by recent models for seasonal thermal variations of Saturn's stratosphere.

Description: An overview of the Voyager 2 encounter with Neptune is presented, including a brief discussion of the trajectory, the planned observations, and highlights of the results described in the 11 companion papers. Neptune's blue atmosphere has storm systems reminiscent of those in Jupiter's atmosphere. An optically thin methane ice cloud exists near the 1.5-bar pressure level, and an optically thick cloud exists below 3 bars. Neptune's magnetic field is highly tilted and offset from the planet's center; it rotates with a period of 16.11 hours. Two narrow and two broad rings circle the planet; the outermost of these rings has three optically thicker arc segments. Six new moons were discovered in circular prograde orbits, all well inside Triton's retrograde orbit. Triton has a highly reflective and geologically young surface, a thin nitrogen atmosphere, and at least two active geyser-like plumes.

Description: Recent models of the internal structure of Pluto and Charon, made possible by analysis of the Pluto/Charon mutual events are reviewed. At a mean density of just over 2 g/cu cm and a predicted rock mass fraction of roughly 0.7, the Pluto/Charon system is significantly rockier than the icy satellites of the giant planets, a contrast which may reflect its formation in a CO-rich outer solar nebula rather than a circumplanetary nebula. Pluto and Charon may in fact be so rocky that they lost volatiles early in their history (possibly during a Charon-forming impact event), although this is still an open issue.

Description: Preliminary results from electric field measurements in the environment of Mars using the plasma-wave system on board Phobos 2 are reported. Electron-plasma oscillations observed upstream of the bow shock correspond to a solar-wind density of 2/cu cm. The shock-foot boundary was crossed up to three times on each orbit. The shock ramp was detected at altitudes between 0.45 and 0.75 Mars radii R(M) above the planetary surface. The density increased by about a factor of two at the ramp. The shock position, although variable, seems to be consistent with previous measurements. The downstream magnetosheath contained broadband electric-field noise below the plasma frequency. The boundary of th obstacle, or plasmapause, was crossed at altitudes of the order of 0.28 R(M); the cold plasma density was highly variable within the planetopause and reached the unexpected value of 700/cu cm on the third orbit, at 0.25 R(M) altitude. Bursts of waves with frequencies below the electron cyclotron frequency occur within the planetopause.

Description: The magnetic fields of Mars have been measured from Phobos 2 with high temporal resolution in the tail and down to an 850-km altitude. During four successive highly elliptical orbits, the position of the bow shock as well as that of a transition layer, the 'planetopause', were identified. Subsequent circular orbits at 6000-km altitude provided the first high-resolution data in the planetary tail and indicate that the interplanetary magnetic field mainly controls the magnetic tail. Magnetic turbulence was also detected when the spacecraft crossed the orbit of Phobos, indicating the possible existence of a torus near the orbit of this moon.

Description: The formation of the ice-rock cores of the giant planets by density wave-assisted accretion is outlined. The process could be rapid (100,000-1,000,000 yr) and completed within the probable lifetime of the solar nebula. The mechanism works for both Jupiter and Saturn and does not require a large excess of mass over that believed present in their cores.

Description: This paper identifies and documents several well-preserved examples of Martian strike-slip faults and examines their relationships to wrinkle-ridges. The strike-slip faulting predates or overlaps periods of wrinkle-ridge growth southeast of Valles Marineris, and some wrinkle ridges may have nucleated and grown as a result of strike-slip displacements along the echelon fault arrays. Lateral displacements of several km inferred along these arrays may be related to tectonism in Tharsis.

Description: Results are presented on the long-term behavior of the main peak electron density in the Venus ionosphere during the solar cycle 21, based on 104 radio occultation measurements of the vertical electron density profile in the dayside ionosphere of Venus carried out aboard the Pioneer Venus Orbiter spacecraft (along with published data on 11 Venera 9-10 measurements). The equation representing the electron temperature at h = 140 km is presented. The results imply that the electron temperature at h = 140 km decreased by about 25 percent from solar maximum to solar minimum, compared to a decrease of 50-75 percent above 200 km found by Kliore and Mullen (1989).

Description: Theoretical models of early Martian atmospheric evolution describe the maintenance of a dense CO2 atmosphere and a warm, wet climate until the end of the heavy-bombardment phase of impacting. However, the presence of very young, earthlike fluvial valleys on the northern flank of Alba Patera conflicts with this scenario. Whereas the widespread ancient Martian valleys generally have morphologies indicative of sapping erosion by the slow outflow of subsurface water, the local Alba valleys were probably formed by surface-runoff processes. Because subsurface water flow might be maintained by hydrothermal energy inputs and because surface-runoff valleys developed late in Martian history, it is not necessary to invoke drastically different planet-wide climatic conditions to explain valley development on Mars. The Alba fluvial valleys can be explained by hydrothermal activity or outflow-channel discharges that locally modified the atmosphere, including precipitation and local overland flow on low-permeability volcanic ash.

Description: On the Mars rover sample-return mission, the rover vehicle will collect and select samples from different locations on the Martian surface to be brought back to earth for laboratory studies. It is anticipated that an in situ energy-dispersive X-ray fluorescence (XRF) spectrometer will be on board the rover. On such a mission, sample selection is of higher priority than in situ quantitative chemical anlaysis. With this in mind, a pattern recognition technique is proposed as a simple, direct, and speedy alternative to detailed chemical analysis of the XRF spectra. The validity and efficacy of the pattern recognition technique are demonstrated by the analyses of laboratory XRF spectra obtained from a series of geological samples, in the form both of standardized pressed pellets and as unprepared rocks. It is found that pattern recognition techniques applied to the raw XRF spectra can provide for the same discrimination among samples as a knowledge of their actual chemical composition.

Description: The present photoelectric lightcurve observations of 44 Nysa at one aspect, and 64 Angelina at both polar aspects, indicate the presence of an opposition spike or brightening of approximately 0.25 mag within several deg of zero-phase angle. Since the three curves are identical within the bounds of observational scatter, the opposition spike cannot be judged anomalous within the asteroid taxonomic class E. The general similarity of the observed phase curves to those of the Uranian satellites and the rings of Saturn supports the status of the spike as an ordinary property of moderate-to-high albedo atmosphereless surfaces.

Description: In order to ascertain the features of organic compound-production in planetary atmospheres under the effects of plasmas and shocks, various mixtures of N2, CH4, and H2 modeling the atmosphere of Titan were subjected to discrete sparks, laser-induced plasmas, and UV radiation. The experimental results obtained suggest that UV photolysis from the plasma is an important organic compound synthesis process, as confirmed by the photolysis of gas samples that were exposed to the light but not to the shock waves emitted by the sparks. The thermodynamic equilibrium theory is therefore incomplete in the absence of photolysis.

Description: An account is given of the results of photometric light curve observations in the V band for asteroids, yielding estimates of the mean and maximum reduced magnitudes for each object. On the basis of fits of the H-G magnitude relation for 33 objects, the mean values of the slope parameter are examined for different taxonomic classes; these values are then applied to the analysis of less complete data sets. While in the case of the moderate albedo S and M class asteroids the H-G relation appears to fit the available data, the relation for dark asteroids appears to predict more of an opposition than is characteristically present.

Description: Voyager imaging, radio occultation, and stellar occultation data for the regular structure of Saturn's inner Cassini Division are presently analyzed. The regular optical depth variation observed by the radio occultation experiment scan and the feature noted in Voyager images is the same structure, namely the gravitational wakes of two 10-km radius satellites orbiting within the division. The structure is azimuthally symmetric, and is judged to rule out the possibility that large moonlets may be responsible for the observed structure.

Description: TEM and IR spectroscopy investigations of the interplanetary dust particles (IDPs) collected in the stratosphere have shown the majority of IDPs in the layer-lattice silicate and pyroxene classes to not have been heated to temperatures above 600 C during atmospheric entry. This implies that they arrive at the upper atmosphere with low geocentric encounter velocities, and limits the possible encounter trajectories for these particles to relatively circular prograde orbits. On this basis, it is judged unlikely that these IDPs are from earth-crossing comets or asteroids; collected IDPs dominated by olivine include a larger portion of above-600 C-heated particles, suggesting their capture from more eccentric orbits.

Description: The present examination of the west Deuteronilus Mensae region of Mars notes the changes in fretted terrain across the gradational boundary from uplands to lowlands to include a reduction of canyon wall slopes and depths, so that the fretted terrain north of the gradational boundary appears matted, but not obscured. The two process-classes that may account for the lateral overlap are the erosion of stratified upland terrain, and the deposition of plains materials onto the sloping upland margin and fretted terrain. A variety of plains-emplacement mechanisms is considered.

Description: The compositional contrast between the giant-planet satellites and the significantly rockier Pluto/Charon system is indicative of different formation mechanisms; cosmic abundance calculations, in conjunction with an assumption of the Pluto/Charon system's direct formation from solar nebula condensates, strongly suggest that most of the carbon in the outer solar nebula was in CO form, in keeping with both the inheritance from the dense molecular clouds in the interstellar medium, and/or the Lewis and Prinn (1980) kinetic-inhibition model of solar nebula chemistry. Laboratory studies of carbonaceous chondrites and Comet Halley flyby studies suggest that condensed organic material, rather than elemental carbon, is the most likely candidate for the small percentage of the carbon-bearing solid in the outer solar nebula.

Description: An attempt is made to provide a constraint on the combined mass of Janus and Epimetheus from an analysis of Voyager I and Voyager 2 data and ground-based observations obtained during the 1966 and 1980 ring plane crossings. The results of the analysis presented here suggest that the total mass is 2.59 + or - 0.26 x 10 to the 21st g, the mass ratio is 3.61 + or - 0.01, and Janus' density is 0.67 + or - 0.10 g/cu cm. The low density of Janus is attributed to its porosity rather than composition.

Description: A coordinated multinational Mars Surveyor Program involving a series of robotic missions is proposed in order to select worthwhile human landing sites for discoveries, for safe operations, and for testing and proving technologies for making human flight to Mars possible. Some characteristics motivating exploration of the planet are briefly discussed, including the possibility of life, geological features, and meteorological conditions. The necessity for preliminary exploration of Mars by robots prior to human exploration is discussed, and the rationale behind a multinational approach for a Mars Surveyor Program is presented.

Description: Arecibo high-resolution (1.5 to 2 km) radar data of Venus for the area extending from Beta Regio to western Eisila Regio provide strong evidence that the mountains in Beta and Eisila Regiones and plains in and adjacent to Guinevere Planitia are of volcanic origin. Recognized styles of volcanism include large volcanic edifices on the Beta and Eisila rises related to regional structural trends, plains with multiple source vents and a mottled appearance due to the ponding of volcanic flows, and plains with bright features surrounded by extensive quasi-circular radar-dark halos. The high density of volcanic vents in the plains suggests that heat loss by abundant and widely distributed plains volcanism may be more significant than previously recognized. The low density of impact craters greater than 15 km in diameter in this region compared to the average density for the higher northern latitudes suggests that the plains have a younger age.

Description: In February and March 1989 the Phobos 2 spacecraft took 37 television images of Phobos from a distance of 190-1100 km. The data are being used to update the three-dimensional model of Phobos, to provide improved determinations of its density and orbital dynamics, and to study its surface color, composition, and texture. Preliminary findings are presented here which include different integrated photometric behavior in visible and near-infrared bands, observation of a region immediately west of Stickney which is relatively free of large grooves, the prevalence of bright rims on grooves and younger craters, and low bulk density.

Description: The nearly ubiquitous presence of a negative Eu anomaly in the mare basalts has been suggested to indicate prior separation and flotation of plagioclase from the basalt source region during its crystallization from a lunar magma ocean (LMO). Are there any mare basalts derived from a mantle source which did not experience prior plagioclase separation? Crystal chemical rationale for REE substitution in pyroxene suggests that the combination of REE size and charge, M2 site characteristics of pyroxene, fO2, magma chemistry, and temperature may account for the negative Eu anomaly in the source region of some types of primitive, low TiO2 mare basalts. This origin for the negative Eu anomaly does not preclude the possibility of the LMO as many mare basalts still require prior plagioclase crystallization and separation and/or hybridization involving a KREEP component.

Description: Pioneer Venus ion composition measurements are used to study the Venus ionosphere during solar minimum. It is suggested that the topside electron density profile at Venus during solar minimum has two distinct regimes. One beween 140 and 180 km is dominated by O2(+) ions which are in photochemical equilibrium. The other regime is above 180 km and is dominated by O(+) ions which are disturbed by the solar wind induced plasma transport. For Pioneer Venus, Mariner 10, and Venera 9 and 10 data, it is found that Venus exhibits a photodynamical type of ionopause during solar minimum.

Description: Voyager 2's IR observations of Neptune encompass thermal emissions and broadband radiometer measurements of reflected solar radiation. Temperature maps were obtained for the planet between 80 deg S and 30 deg N for two atmospheric layers, one in the lower stratosphere and the other in the troposphere. The relatively warm pole and equator, with cooler midlatitudes, are qualitatively similar to Uranus, despite the two planets' very different obliquities and internal heat fluxes. Powerful wavelike longitudinal thermal structure is noted, of which some appears to be associated with the Great Dark Spot; a localized cold region uncorrelated with any visible feature is found in the lower stratosphere.

Description: Detection of very intense short radio bursts from Neptune was possible as early as 30 days before closest approach and at least 22 days after closest approach. The bursts lay at frequencies in the range 100 to 1300 kilohertz, were narrowband and strongly polarized, and presumably originated in southern polar regions of the planet. Episodes of smooth emissions in the frequency range from 20 to 865 kilohertz were detected during an interval of at least 10 days around closest approach. The bursts and the smooth emissions can be described in terms of rotation in a period of 16.11 + or - 0.05 hours. The bursts came at regular intervals throughout the encounter, including episodes both before and after closest approach. The smooth emissions showed a half-cycle phase shift between the five episodes before and after closest approach. This experiment detected the foreshock of Neptune's magnetosphere and the impacts of dust at the times of ring-plane crossings and also near the time of closest approach. Finally, there is no evidence for Neptunian electrostatic discharges.

Description: Based on the success of several two-dimensional (latitude, longitude) linear barotropic instability models at matching some of the observed characteristics of the cloud level, polar region of the Venus atmosphere, a more realistic, linear, three-dimensional (height, latitude and longitude) model has been developed to further test the hypothesis that the observed features can be described by linear instability theory. The approach taken is to vary the model input parameters to see whether it is possible to produce modes that resemble the observations of wave activity and to compare those input parameters with other observations of the mean state. Sensitivity studies show that in addition to a well-documented dependence on the mean zonal wind, the growth and propagation of unstable modes depends on the latitude variation of the mean temperature (and hence static stability). These studies have led to the specification of a model basic state wind and temperature field that produces modes which are matched to observations of spatial structure, preferred wavenumber and phase speed of the polar disturbances. Wavenumber 2 is found to have the shortest growth time and unlike the two-dimensional results, wavenumbers 1-3 share a nearly common period of about 3 days. The derived basic state has a temperature field that is quite similar to Pioneer Venus observations; however, in some regions the model basic state wind field departs from cyclostrophic values based on temperature observations.

Description: Particles in the mass range from 10 to the minus 7th power to 10 to the minus 3rd power grams contribute 80 percent of the total mass influx of meteoritic material in the 10 to the minus 13th power to 10 to the 6th power gram mass range at Earth (Hughes, 1978). On Earth atmospheric entry, all but the smallest particles in the 10 to the minus 7th power to 10 to the minus 3rd power gram mass range, about 60 to 1200 micrometers in diameter, are heated sufficiently to melt and vaporize. Mars, because of its lower escape velocity and larger atmospheric scale height, is a much more favorable site for unmelted survival of micrometeorites on atmospheric deceleration. Researchers calculate that a significant fraction of particles throughout the 60 to 1200 micrometer diameter range will survive atmospheric entry unmelted. Thus returned Mars soils may offer a resource for sampling micrometeorites in a size range uncollectable in unaltered form at Earth. The addition of meteoritic material to the Mars soils should perturb their chemical composition, as has been detected using the soils on the Moon (Anders, et al., 1973). Using measured mass influx at Earth and estimates of the Mars/Earth flux ratio, researchers estimate a mass influx at Mars of between 2,700 and 202,000 metric tons per year.

Description: A central question for any planet is the age of its surface. Based on comparative planetological arguments, Venus should be as young and active as the Earth (Wood and Francis). The detection of probable impact craters in the Venera radar images provides a tool for estimating the age of the surface of Venus. Assuming somewhat different crater production rates, Bazilevskiy et al. derived an age of 1 + or - 0.5 billion years, and Schaber et al. and Wood and Francis estimated an age of 200 to 400 million years. The known impact craters are not randomly distributed, however, thus some area must be older and others younger than this average age. Ages were derived for major geologic units on Venus using the Soviet catalog of impact craters (Bazilevskiy et al.), and the most accessible geologic unit map (Bazilevskiy). The crater counts are presented for (diameters greater than 20 km), areas, and crater densities for the 7 terrain units and coronae. The procedure for examining the distribution of craters is superior to the purely statistical approaches of Bazilevskiy et al. and Plaut and Arvidson because the bins are larger (average size 16 x 10(6) sq km) and geologically significant. Crater densities define three distinct groups: relatively heavily cratered (Lakshmi, mountain belts), moderately cratered (smooth and rolling plains, ridge belts, and tesserae), and essentially uncratered (coronae and domed uplands). Following Schaber et al., Grieve's terrestrial cratering rate of 5.4 + or - 2.7 craters greater than 20 km/10(9) yrs/10(6) sq km was used to calculate ages for the geologic units on Venus. To improve statistics, the data was aggregated into the three crater density groups, deriving the ages. For convenience, the three similar age groups are given informal time stratigraphic unit names, from youngest to oldest: Ulfrunian, Sednaian, Lakshmian.

Description: The Tellus Regio area of Venus represents a subset of a narrow latitude band where Pioneer Venus Orbiter (PVO) altimetry data, line-of-sight (LOS) gravity data, and Venera 15/16 radar images have all been obtained with good resolution. Tellus Regio also has a wide variety of surface morphologic features, elevations ranging up to 2.5 km, and a relatively low LOS gravity anomaly. This area was therefore chosen in order to examine the theoretical stress distributions resulting from various models of compensation of the observed topography. These surface stress distributions are then compared with the surface morphology revealed in the Venera 15/16 radar images. Conclusions drawn from these comparisons will enable constraints to be put on various tectonic parameters relevant to Tellus Regio. The stress distribution is calculated as a function of the topography, the equipotential anomaly, and the assumed model parameters. The topography data is obtained from the PVO altimetry. The equipotential anomaly is estimated from the PVO LOS gravity data. The PVO LOS gravity represents the spacecraft accelerations due to mass anomalies within the planet. These accelerations are measured at various altitudes and angles to the local vertical and therefore do not lend themselves to a straightforward conversion. A minimum variance estimator of the LOS gravity data is calculated, taking into account the various spacecraft altitudes and LOS angles and using the measured PVO topography as an a priori constraint. This results in an estimated equivalent surface mass distribution, from which the equipotential anomaly is determined.

Description: Previous analyses have recognized several styles and orientations of compressional deformation, crustal convergence, and crustal thickening in Eastern Ishtar Terra. An east to west sense of crustal convergence through small scale folding, thrusting, and buckling is reflected in the high topography and ridge-and-valley morphology of Maxwell Montes and the adjacent portion of Fortuna Tessera. This east to west convergence was accompanied by up to 1000 km of lateral motion and large scale strike-slip faulting within two converging shear zones which has resulted in the present morphology of Maxwell Montes. A more northeast to southwest sense of convergence through large scale buckling and imbrication is reflected in large, northwest-trending scarps along the entire northern boundary of Ishtar Terra, with up to 2 km of relief present at many of the scarps. It was previously suggested that both styles of compression have occurred at the expense of pre-existing tessera regions which have then been overprinted by the latest convergence event. The difference in style is attributed mostly to differences in the properties of the crust converging with the tessera blocks. If one, presumably thick, tessera block converges with another tessera region, then the widespread, distributed style of deformation occurs, as observed in western Fortuna Tessera. However, if relatively thin crust (such as suggested for the North Polar Plains converges with thicker tessera regions, then localized deformation occurs, as reflected in the scarps along Northern Ishtar Terra. The purpose is to identify the types of features observed in Eastern Ishtar Terra. Their potential temporal and spatial relationships, is described, possible origins for them is suggested, and how the interpretation of some of these features has led to the multiple-style tectonic evolution model described is shown.

Description: The Venera 15/16 spacecraft revealed a number of features of unknown origin including coronae, elongate to circular structures with a complex interior surrounded by an annulus of concentric ridges. Eighteen coronae were identified in Venera 15/16 data of Venus; an additional thirteen possible coronae are found in Pioneer Venus and Arecibo data. Coronae, with maximum widths of 160 to over 650 km, are found primarily in two clusters in the Northern Hemisphere located to the east and west of Ishtar Terra. Another possible cluster is located in Themis Regio in the Southern Hemisphere. The majority of coronae are at least partially raised less than 1.5 km above the surrounding region, and over half are partially surrounded by a peripheral trough. A sequence of events for coronae has been determined through mapping. Prior to corona formation, regional compression or extension creates bands of lineaments along which coronae tend to later form. During the early stages of corona formation, relatively raised topography is produced by uplift and volcanic construction. The evolution of coronae and their general characteristics have been compared to two models of corona origin: hotspots and sinking mantle diapirs. In the hotspot or rising mantle diapir model, heating and melting at depth create uplift at the surface. Uplift is accompanied by central extension, facilitating volcanism. Gravitational relaxation of the uplifted region follows producing the compressional features within the annulus and the peripheral trough. Both models can predict the major characteristics and evolutionary sequence of coronae. The sinking diapir model does predict an early-time low and central compression as well as broadening and shallowing of the peripheral trough with time, all of which are not observed at current data resolution. In addition, the sinking mantle diapir mode predicts more simultaneous formation of the high topography, annulus and trough unlike the hotspot or rising mantle diapir mode. High resolution Magellan data will be used to distinguish between the two models of corona origin.

Description: The average surface age of a planet is a major indicator of the level of its geologic activity and thus of the dynamics of its interior. Radar images obtained by Venera 15/16 from the northern quarter of the Venus (lat 30 to 90 degs) reveal about 150 features that resemble impact craters, and they were so interpreted by Soviet investigators B. A. Ivanov, A. T. Basilevsky, and their colleagues. These features range in diameter from about 10 to 145 km. Their areal density is remarkably similar to the density of impact structures found on the American and European continental shields. The basic difference between the Soviet and American estimates of the average surface age of Venus's northern quarter is due to which crater-production rate is used for the Venusian environment. Cratering rates based on the lunar and terrestrial cratering records, as well as statistical calculations based on observed and predicted Venus-crossing asteroids and comets, have been used in both the Soviet and American calculations. The single largest uncertainty in estimating the actual cratering rates near Venus involves the shielding effect of the atmosphere.

Description: The surface characteristics and morphology of the equatorial region of Venus were first described by Masursky et al. who showed this part of the planet to be characterized by two topographic provinces, rolling plains and highlands, and more recently by Schaber who described and interpreted tectonic zones in the highlands. Using Pioneer Venus (PV) radar image data (15 deg S to 45 deg N), Senske and Head examined the distribution, characteristics, and deposits of individual volcanic features in the equatorial region, and in addition classified major equatorial physiographic and tectonic units on the basis of morphology, topographic signature, and radar properties derived from the PV data. Included in this classification are: plains (undivided), inter-highland tectonic zones, tectonically segmented linear highlands, upland rises, tectonic junctions, dark halo plains, and upland plateaus. In addition to the physiographic units, features interpreted as coronae and volcanic mountains have also been mapped. The latter four of the physiographic units along with features interpreted to be coronae.

Description: The outer layers of the Venusian lithosphere appear to dissipate heat from the interior through mantle-driven thermal anomalies (hot spots, swells). As a result, Venus exhibits diverse forms of thin-skin tectonism and magmatic transfer to and extrusion from countless numbers of volcanic centers (e.g., shields, paterae, domes) and volcano-tectonic complexes (e.g., coronae, arachnoids). What is known about the distribution and morphologies of major Venusian shields is summarized, and the evidence for possible structural control of major accumulations as long as 5000 km of small volcanic domes is described.

Description: A major component of the 1988 Mojave Field Experiment involved the simultaneous acquisition of quad-polarization multifrequency airborne Synthetic Aperture Radar (SAR) imaging radar data and ground measurements thought to be relevant to the radar scattering behavior of a variety of desert surfaces. In preparation for the Magellan mission to Venus, the experiment was designed to explore the ability of SAR to distinguish types of geological surfaces, and the effects of varying incidence angles on the appearance of such surfaces. The airborne SAR system acquired images at approx. 10 m resolution, at 3 incidence angles (30, 40, 50 degs) and at 3 wavelengths (P:68 cm, L:24 cm, C:5.6 cm). The polarimetric capabilities of the instrument allow the simulation of any combination of transmit and receive polarizations during data reduction. Calibrated trihedral corner reflectors were deployed within each scene to permit absolute radiometric calibration of the image data. Initial analyses of this comprehensive radar data set is reported, with emphasis on implications for interpretation of Magellan data.

Description: Lakshmi Planum, a broad smooth plain located in western Ishtar Terra and containing two large oval depressions (Colette and Sacajawea), has been interpreted as a highland plain of volcanic origin. Lakshmi is situated 3 to 5 km above the mean planetary radius and is surrounded on all sides by bands of mountains interpreted to be of compressional tectonic origin. Four primary characteristics distinguish Lakshmi from other volcanic regions known on the planet, such as Beta Regio: (1) high altitude, (2) plateau-like nature, (3) the presence of very large, low volcanic constructs with distinctive central calderas, and (4) its compressional tectonic surroundings. Building on the previous work of Pronin, the objective is to establish the detailed nature of the volcanic deposits on Lakshmi, interpret eruption styles and conditions, sketch out an eruption history, and determine the relationship between volcanism and the tectonic environment of the region.

Description: Clotho Tessera, adjacent to southeast Lakshmi Planum, may provide additional evidence for lateral crustal motions, and a model for the origin of small tessera fragments. Clotho Tessera and Lakshmi Planum are so noticeably different, and in such close proximity, it is difficult to derive a reasonable model of their formation in situ. Squeezing of material out from beneath Lakshmi has been suggested as an origin for Moira Tessera, which is also adjacent to Lakshmi and 1400 km west of Clotho. However, a logical model of juxtaposition of the two different terrains, originally from points once distant, can be made for Clotho and Lakshmi (and perhaps other small tesserae as well). It is suggested that Clotho Tessera was once part of Fortuna Tessera, but was cut off by a transcurrent fault zone (the DLZ) striking perpendicular to the Sigrun rift and carried westward where it collided with Lakshmi Planum (forming Danu Montes). A gravity anomaly along the southern border of Lakshmi, in the area of Danu Montes, was interpreted as indicating subduction there, providing additional supporting evidence for the collision hypothesis. Diffusion of the DLZ with proximity to Sigrun Fossae may be due to either higher ductility near the postulated Sigrun rift, or to burial by flows away from the rift nearer to Valkyrie Fossae. Other possible examples of migrating tesserae occur elsewhere: small pieces of Ananke Tessera can be fit back together as though they had rifted apart, and the spreading apart of Ananke and Virilis Tesserae has been suggested because of their symmetric locations about the axis of an inferred spreading zone. Other tessera fragments appear to have been isolated by rifting, with little, if any, significant lateral motion (e.g., Meni and Tellus Tesserae, and Thethus and Fortuna Tesserae). The migrating terrain model for Clotho Tessera supports Sukhanov's interpretation of tesseral fragments as rafts of lighter crustal material.

Description: Linear mountain belts in Ishtar Terra were recognized from Pioneer-Venus topography, and later Arecibo images showed banded terrain interpreted to represent folds. Subsequent analyses showed that the mountains represented orogenic belts, and that each had somewhat different features and characteristics. Orogenic belts are regions of focused shortening and compressional deformation and thus provide evidence for the nature of such deformation, processes of crustal thickening (brittle, ductile), and processes of crustal loss. Such information is important in understanding the nature of convergent zones on Venus (underthrusting, imbrication, subduction), the implications for rates of crustal recycling, and the nature of environments of melting and petrogenesis. The basic elements of four convergent zones and orogenic belts in western Ishtar Terra are identified and examined, and then assess the architecture of these zones (the manner in which the elements are arrayed), and their relationships. The basic nomenclature of the convergent zones is shown.

Description: This review assesses the potential aeolian regime on Venus as derived from spacecraft observations, laboratory simulations, and theoretical considerations. The two requirements for aeolian processes (a supply of small, loose particles and winds of sufficient strength to move them) appear to be met on Venus. Venera 9, 10, 13, and 14 images show particles considered to be sand and silt size on the surface. In addition, dust spurts (grains 5 to 50 microns in diameter) observed via lander images and inferred from the Pioneer-Venus nephalometer experiments suggest that the particles are loose and subject to movement. Although data on near surface winds are limited, measurements of 0.3 to 1.2 m/sec from the Venera lander and Pioneer-Venus probes appear to be well within the range required for sand and dust entrainment. Aeolian activity involves the interaction of the atmosphere, lithosphere, and loose particles. Thus, there is the potential for various physical and chemical weathering processes that can effect not only rates of erosion, but changes in the composition of all three components. The Venus Simulator is an apparatus used to simulate weathering under venusian conditions at full pressure (to 112 bars) and temperature (to 800 K). In one series of tests, the physical modifications of windblown particles and rock targets were assessed and it was shown that particles become abraded even when moved by gentle winds. However, little abrasion occurs on the target faces. Thus, compositional signatures for target rocks may be more indicative of the windblown particles than of the bedrock. From these and other considerations, aeolian modifications of the venusian surface may be expected to occur as weathering, erosion, transportation, and deposition of surficial materials. Depending upon global and local wind regimes, there may be distinctive sources and sinks of windblown materials. Radar imaging, especially as potentially supplied via the Magellan mission, may enable the identification of such areas on Venus.

Description: The geomorphic expression of Mid-Ocean-Ridge (MOR) volcanism in a subaerial setting occurs uniquely on Earth in Iceland, and the most recent MOR eruptive activity has been concentrated in the Northeastern Volcanic Zone in an area known as Krafla. Within the Krafla region are many of the key morphologic elements of MOR-related basaltic volcanism, as well as volcanic explosion craters, subglacial lava shields, tectonic fissure swarms known as gjar, and basaltic-andesite flows with well developed ogives (pressure-ridges). The objective was to quantify the degree to which the basic volcanic and structural features can be mapped from directional SAR imagery as a function of the look azimuth. To accomplish this, the current expression of volcanic and tectonic constructs was independently mapped within the Krafla region on the E, W, and N-looking SAR images, as well as from SPOT Panchromatic imagery acquired in 1987. The initial observations of the E, W, and N images indicates that fresh a'a lava surfaces are extremely radar bright (rough at 3 cm to meter scales) independent of look direction; this suggests that these flows do not have strong flow direction related structures at meter and cm scales, which is consistent with typical Icelandic a'a lava surfaces in general. The basic impression from a preliminary analysis of the effects of look azimuth biasing on interpretation of the geology of an active MOR volcanic zone is that up to 30 percent of the diagnostic features can be missed at any given look direction, but that having two orthogonal look direction images is probably sufficient to prevent gross misinterpretation.

Description: Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred larg/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas.

Description: The modes of lithospheric heat transfer and the tectonic styles may differ between Earth and Venus, depending on how the high surface temperature (700 K = 430 C), dense and opaque atmosphere (approx. 10 MPa = 100 bars), lack of water oceans, and the other known ways in which Venus differs from Earth, influence basic lithospheric processes, thermal gradient, upper mantle temperature, thermal and chemical evolution, and convection. A fundamental question is whether the lithosphere of Venus is horizontally stable, like the other terrestrial planets, or is mobile like that on Earth. The variety of characteristics, their integrated relationships, and their predictable behavior throughout Western Aphrodite Terra are similar to those features known to occur in association with the terrestrial seafloor at spreading centers and divergent plate boundaries. It is concluded that Western Aphrodite Terra represents the site of crustal spreading centers and divergent plate boundaries. The extent of similar characteristics and processes elsewhere on Venus outside of the 13,000 km long Western and Eastern Aphrodite Terra rise is unknown at the present, but their presence in other areas of the equatorial highlands, suggested from recent analysis, may be tested with forthcoming Magellan data.

Description: Ridge belts, first identified in the Venera 15/16 images are distinguished as linear regions of concentrated, parallel to anastomosing, ridges. They are tens to several hundreds of km wide, hundreds to over one thousand km long, and composed of individual ridges 5 to 20 km wide and up to 200 km long. The ridges appear symmetrical in the radar images and are either directly adjacent to each other or separated by mottled plains. Cross-strike lineaments, visible as dark or bright lines, are common within the ridge belts, and some truncate individual ridges. In places the ridge belt may be offset by these lineaments, but such offset is rarely consistent across the ridge belt. Once the mode of formation of these ridge belts is understood, their distribution and orientation will help to constrain the homogeneity and orientation of the stresses over the period of ridge belt formation. The look direction for the Venera system was to the west, so ridges appear as pairs of bright and dark lineaments, with the bright line to the east of the dark. The term ridge was used in a general sense to refer to a linear rise. The use of this term is restricted to rises which have a sharp transition from bright to dark at the crest, and are 5 to 15 km wide. These ridges are either continuous or discontinuous. The continuous ridges are over 30 km long and form coherent ridge belts, while the discontinuous ridges are less than 30 km long and do not form a coherent ridge belt. The continuous ridges were divided into 3 components: (1) Anastomosing ridges, in which the individual ridges are sinuous and often meet and cross at small angles, are the most common component; (2) The parallel ridge component also consists of well defined ridges, often with plains separating the individual ridges, but the ridges are more linear and rarely intersect one another; and (3) Parallel ridged plains are composed of indistinct ridges, some of which do not have a distinctive bright-dark pattern. The nature of deformation within the ridge belts is complex and not fully understood at present. Some belts show distinct signs of compression, while others have symmetrical patterns expected in extensional environments. Thus the ridge belts may have formed by more than one style of deformation; some may be extensional, while others are compressional. All the ridge belts are being systematically mapped, especially for symmetrical relationships.