NASA Research and Technology Studies (RATS) 2012: Virtual Simulation and Evaluation of Human and Robotic Systems for Exploration of Near-Earth Asteroids

Abstract

The NASA Research and Technology Studies (RATS) 2012 test focused on optimizing utilization of a four-person crew, deep space habitat (DSH), multi-mission space exploration vehicle (MMSEV), extravehicular activity (EVA) jetpacks, and Mission Control Center operating with 50-seconds each-way communication latency during exploration within an immersive virtual-reality simulation of the near-Earth asteroid (NEA) Itokawa. Test subjects operated the MMSEV and interacted with the simulation environment from inside an MMSEV prototype while viewing the simulation on video walls through the MMSEV windows. Head-mounted displays, instrumented gloves, and an EVA jetpack control module were used during simulated free-flying EVAs while a gravity offloading system was used during simulated anchored EVAs. Simulation telemetry and consensus subjective ratings were used to assess, evaluate, and compare exploration traverses incorporating different combinations of extravehicular and intravehicular crewmembers; anchored versus freeflying operations; EVA jetpacks versus astronaut positioning system (APS) attached to the MMSEV; and NEA size and spin rates. Human factors of the Generation 2A MMSEV prototype were evaluated by two separate two-person crews, each inhabiting the MMSEV for 3 days and 2 nights. For the operations tested, the recommended distribution of crewmembers is two in the DSH, one in the MMSEV, and one EVA. Crewmembers rated this condition as “Acceptable” and experienced lower workload and greater situational awareness versus conditions involving two EVA crewmembers. Free-flying modes were preferred versus anchoring the MMSEV to the NEA because of decreased overhead and increased situational awareness, although propellant savings of 31% were estimated with anchoring. Alternating between APS and jetpack (versus APS only) did not improve acceptability but may reduce propellant usage. MMSEV Delta-V usage during manual station-keeping  ω 2 x r, where ω = NEA angular velocity and r = distance from spin axis. Human factors of the Generation 2A MMSEV were rated “Acceptable” overall.