ALBERT

Description: Space vehicle staging and separation events require pyrotechnic devices. They are single-use mechanisms that cannot be tested, nor can failure-tolerant performance be demonstrated in actual flight articles prior to flight use. This necessitates the implementation of a robust design and test approach coupled with a fully redundant, failure-tolerant explosive mechanism to ensure that the system functions even in the event of a single failure. Historically, NASA has followed the single failure-tolerant (SFT) design philosophy for all human-rated spacecraft, including the Space Shuttle Program. Following the end of this program, aerospace companies proposed building the next generation human-rated vehicles with off-the-shelf, non-redundant, zero-failure-tolerant (ZFT) separation systems. Currently, spacecraft and launch vehicle providers for both the Orion and Commercial Crew Programs (CCPs) plan to deviate from the heritage safety approach and NASA's SFT human rating requirements. Both programs' partners have base-lined ZFT frangible joints for vehicle staging and fairing separation. These joints are commercially available from pyrotechnic vendors. Non-human-rated missions have flown them numerous times. The joints are relatively easy to integrate structurally within the spacecraft. In addition, the separation event is debris free, and the resultant pyro shock is lower than that of other design solutions. It is, however, a serious deficiency to lack failure tolerance. When used for critical applications on human-rated vehicles, a single failure could potentially lead to loss of crew (LOC) or loss of mission (LOM)). The Engineering and Safety & Mission Assurance directorates within the NASA Johnson Space Center took action to address this safety issue by initiating a project to develop a fully redundant, SFT frangible joint design, known as the Flat H. Critical to the ability to retrofit on launch vehicles being developed, the SFT mechanisms must fit within the same three-dimensional envelope as current designs as well as meet structural loads requirements. There is increased mass associated with the redundant design, and the goal is to minimize the weight impact as much as possible. These requirements presented significant challenges, both technically and financially; these challenges will be explored in this paper. Perhaps greater than the technical issues confronted during this design process, were the financial considerations. These were a significant part of the story of this design and development plan. Insufficient financial and labor resources were formidable barriers to completing this project. Nevertheless, JSC personnel successfully conducted several test series at JSC with very useful results. The many lessons learned drove design improvements, performance efficiency, and increased functional reliability. This paper examines the significant technical and financial challenges that these requirements posed to the project team. It discusses the evolution of the SFT frangible joint design, including optimization, testing, and successful partnering of the Johnson Space Center (JSC) engineering and JSC safety organizations, to enhance the flight safety margin for America's next generation of human-rated space vehicles.

Description: This paper reports results of an investigation into developing a single failure tolerant pyrotechnic linear separation system which features completely redundant explosive trains suitable for human spaceflight. It is a follow up to Flat-H Redundant Frangible Joint Design Evolution 2017 and Flat-H Redundant Frangible Joint Evolution. The paper chronicles the history of the redundant frangible joint development program including testing, analysis, and design improvements from 2014 to the present culminating in a successful proof-of-concept prototype. The paper describes work done to address debris control and containment of combustion products. A performance optimization strategy is presented along with optimization results. Additionally a novel containment manifold design is presented with test results.

Description: Orbital Communications Adaptor (OCA) Flight Controllers, in NASA's International Space Station Mission Control Center, use different computer systems to uplink, downlink, mirror, archive, and deliver files to and from the International Space Station (ISS) in real time. The OCA Mirroring System (OCAMS) is a multiagent software system (MAS) that is operational in NASA's Mission Control Center. This paper presents OCAMS and its workings in an operational setting where flight controllers rely on the system 24x7. We also discuss the return on investment, based on a simulation baseline, six months of 24x7 operations at NASA Johnson Space Center in Houston, Texas, and a projection of future capabilities. This paper ends with a discussion of the value of MAS and future planned functionality and capabilities.