Exploration of Near-Earth Objects via the Orion Crew Exploration Vehicle: A Planetary Defence Rationale.
Abell, P. A.¹; Korsmeyer, D. J.²; Landis, R. R.³; Jones, T. D.⁴; Adamo, D.⁵; Morrison, D.⁶; Lemke, L.⁶; Gonzales, A.⁶; Gershman, B.⁷; Sweetser, T.⁷; Johnson, L.^8
1NASA Johnson Space Center / Planetary Science Institute; ²Intelligent Systems Division, NASA Ames Research Center; ³Mission Operations Directorate, NASA Johnson Space Center; ⁴Association of Space Explorers; ⁵Trajectory Consultant; ⁶NASA Ames Research Center; ⁷Jet Propulsion Laboratory; ⁸NASA Headquarters

Introduction: The concept of a crewed mission to a Near-Earth Object (NEO) has been considered since the early stages of the Apollo program and has been analyzed in depth as part of the Space Exploration Initiative. Several other studies have also investigated the possibility of sending similar missions to NEOs. A more recent study has been sponsored by the Advanced Projects Office within NASA's Constellation Program to examine the feasibility of sending a Crew Exploration Vehicle (CEV) to a NEO. The ideal mission profile would involve 2 or 3 astronauts on a 90 to 180 day flight, which would include a 7 to 14 day stay for proximity operations at the target NEO. This mission would be the first human expedition to an interplanetary body beyond cislunar space and would prove useful for testing technologies required for deflecting potentially hazardous objects.

Scientific and Practical Implications: Piloted missions using the CEV to NEOs would not only provide a great deal of technical and engineering data on spacecraft operations for future human space exploration, but would also provide the capability to conduct an in-depth scientific investigation of these objects. From a scientific perspective missions to NEOs are vital to understanding the evolution and thermal histories of these bodies during formation of the early solar system, and to identifying potential source regions from which NEOs originate. NEO exploration missions would also have practical applications for resource utilization and planetary defense, two issues that will be relevant in the not-too-distant future as humanity begins to explore, understand, and utilize the solar system. A significant portion of the NEO population may contain water, an invaluable source of life support and propellant for future deep space missions. The subject of planetary defence from impacting asteroids has garnered much public and Congressional interest recently because of the increasing discovery rate of asteroids with a small but non-zero probability of striking Earth. Many proposed deflection schemes depend critically on asteroid characteristics such as density, internal structure, and material properties - precisely the parameters a crewed mission to a NEO could measure.

CEV Capabilities: A CEV mission would have a much greater capability for NEO science and exploration than would robotic spacecraft. The main advantage of having piloted missions to a NEO is the flexibility of the crew to perform tasks and to adapt to situations in real time. A human crew is able to perform tasks and react more quickly in a micro-gravity environment than any robotic spacecraft could (rapid yet delicate maneuvering has been a hallmark of Gemini, Apollo, Skylab, and Shuttle operations). In addition, a crewed vehicle would be able to test several different sample collection techniques and target specific areas of interest via extra-vehicular activities (EVAs) much more capably than a robotic spacecraft. Such capabilities would greatly enhance any scientific return from missions to NEOs, and would enable a better understanding of these objects physical characteristics, which is necessary for developing future NEO hazard mitigation techniques.