|The Global Exploration Roadmap (GER) outlines a series of lunar vicinity missions that include the Space Launch System (SLS) and the Orion spacecraft. Orion is being prepared for an Exploration Flight Test (EFT)-1 on a Delta IV in December 2014, followed by Exploration Mission One (EM-1) on the SLS in 2017, the latter of which is an un-crewed flight to a distant retrograde orbit around the Moon. EM-2 follows in 2021 with a crewed lunar orbit-capable system. With that orbital capability, astronauts could interact with a robotic asset on the lunar surface to facilitate sample return. Indeed, the GER anticipates human-assisted sample return within the decade and humans to the lunar surface are scheduled about four years later.
A multi-year Global Lunar Landing Site Study to Provide the Scientific Context for Exploration of the Moon (Kring and Durda (eds.), 2012, LPI Contribution No. 1694) found that the Schrödinger and South Pole-Aitken basins are two high-priority targets. To adequately address both scientific and exploration objectives, sample return missions are required. The best results would be obtained by a trained crew on the lunar surface, but a productive iterative step would be to deploy a robotic asset to the lunar surface that is coordinated with an Orion flight. One of several potential landing sites within the Schrödinger basin would provide access to a pyroclastic deposit with ISRU potential and impact-generated lithologies that can help test the lunar cataclysm hypothesis and lunar magma ocean hypothesis.
In a human-assisted sample return mission, astronauts on NASA’s Orion vehicle and ESA’s service module could be sent to an orbit around the Earth-Moon L2 point ~60,000 km above the lunar far side surface or to a distant retrograde orbit (DRO) that also passes over the far side surface. Currently, the target DRO passes ~70,000 km above the lunar far side. In parallel, a robotic asset could land within the Schrödinger and/or South Pole-Aitken basins and collect samples for return to Earth. A lander and rover could maintain contact with Earth through Orion. Moreover, astronauts on Orion could teleoperate the rover to reduce mission risk, enhance scientific return, and test operational concepts for future missions, including those needed to execute a Mars exploration program. An ascent vehicle on the robotic asset could return samples to the Orion vehicle for return to Earth or, with the addition of a capsule, directly to Earth.
Our studies of mission operation time lines indicate Orion would have 20 and 10 days of communication with the surface asset from an L2 orbit or DRO orbit, respectively, while accommodating ascent vehicle rendezvous for sample transfer to Orion with a total mission duration of about a month.