[Show abstract][Hide abstract] ABSTRACT: This trade study was conducted as a part of the Orion landing system advanced development project to determine possible terminal descent sensor (TDS) architectures that could be used for a rocket assisted landing system. Several technologies were considered for the Orion TDS including radar, lidar, GPS applications, mechanical sensors, and gamma ray altimetry. A preliminary down selection occurred by comparing each sensor's ability to meet the requirements. The driving requirements included the range of operation, accuracy, and sensor development to a technology readiness level of 6 (TRL-6) by the Orion PDR in June 2008. Additionally, Orion is very mass and volume constrained, so these parameters were weighted heavily. Radar, lidar, and GPS applications all had potential to meet the requirements and were carried on for further analysis. Investigation into GPS led to concerns over potential loss of signal and required ground infrastructure, so GPS was taken out of the trade space. Remaining technologies included a pulse-Doppler radar, FMCW radar, and a hybrid lidar ranger and velocimeter (termed the hybrid lidar). The trade boils down to the maturity and weather robustness of the radar options versus the mass, volume, power, and heat shield blowout port size advantage of the lidar. This trade study did not result in a recommended TDS. The trade of the mass and volume impact versus the development time and cost should be made at a higher level than this particular trade study.
[Show abstract][Hide abstract] ABSTRACT: In 2010, the Mars science laboratory (MSL) mission will pioneer the next generation of robotic entry, descent, and landing (EDL) systems by delivering the largest and most capable rover to date to the surface of Mars. In addition to landing more mass than prior missions to Mars, MSL will offer access to regions of Mars that have been previously unreachable. The MSL EDL sequence is a result of a more stringent requirement set than any of its predecessors. Notable among these requirements is landing a 900 kg rover in a landing ellipse much smaller than that of any previous Mars lander. In meeting these requirements, MSL is extending the limits of the EDL technologies qualified by the Mars viking, Mars pathfinder, and Mars exploration rover missions. Thus, there are many design challenges that must be solved for the mission to be successful. Several pieces of the EDL design are technological firsts, such as guided entry and precision landing on another planet, as well as the entire sky crane maneuver. This paper discusses the MSL EDL architecture and discusses some of the challenges faced in delivering an unprecedented rover payload to the surface of Mars.