HUBBLE SPACE TELESCOPE SERVICING: A CASE STUDY IN ANALYSIS AND PRESENTATION OF SPACE PROGRAM RISK INFORMATION

摘要

NASA requested that The Aerospace Corporation perform a nonadvocate assessment of Hubble Space Telescope (HST) robotic servicing alternatives. These alternatives encompassed a broad range of options in the following families: ground life extension, disposal, rehosting instrumentation on other platforms, robotic servicing, and the baseline Shuttle Servicing Mission 4 (SM4) previously planned for 2005. In developing this analyses of alternatives (AoA), Aerospace assessed each alternative against a set of measures of effectiveness (MOEs), which included cost, schedule, risk, and the resulting capability of the alternative to perform science relative to the planned post-SM4 baseline. The key findings of this AoA are: 1. Ground-based life extension does not replace instruments and does not address the risk associated with uncontrolled HST reentry. 2. Disposal-only alternatives have relatively low cost, but provide no HST life extension or added science capability comparable to the current configuration. 3. Rehost alternatives provide higher value at equivalent cost to the robotic servicing missions, but may result in a two- to sevenyear science gap. This higher value results from the lower development and mission risks. 4. Robotic servicing alternatives, based on estimated development schedules, are susceptible to arriving too late. HST may no longer be in a serviceable state. Furthermore, they are subject to an aging observatory that may fail for some other reason during the three years following servicing. 5. SM4 has costs in the same range as the rehost and robotic servicing alternatives, has higher probability of mission success than the robotic servicing missions, and does not suffer from the gap in science associated with rehost alternatives.1 Other means to perform SM4 with reduced risk by launching a safe habitat or relocating HST to the vicinity of the International Space Station (ISS) were examined, but would require more development time and be more costly.