Issues arising from the NASA safety standard to control orbital debris

Abstract

In 1992 NASA adopted a policy to limit the generation of orbital debris. This policy is stated in NASA Management Instruction (NMI) 1700.8, and provides a general statement of policy to take action to limit orbital debris generation if this action is cost effective and consistent with achieving mission objectives. The only specific requirement in the policy is to perform debris assessments during development of NASA programs. To implement this policy, the NASA Office of Safety and Mission Assurance, the sponsor of NMI 1700.8, tasked NASA Johnson Space Center (JSC) with developing guidelines to implement the policy. This tasking resulted in the development of NASA Safety Standard 1740.14: Guidelines and Assessment Procedures for Limiting Orbital Debris . The Safety Standard has been reviewed and approved by all NASA organizations and NASA programs are now required to perform two debris evaluations, one at Preliminary Design Review (PDR) and a second 45 days prior to Critical Design Review, once the final space system design has been approved. The purpose of the first report is to identify potential problems that a program may encounter in meeting the guidelines, and the second report is to document efforts by the program to resolve those problems. At this point in time, a primary concern by NASA managers has been the issue of postmission disposal of low Earth orbit systems and upper stages left in high eccentricity orbits. These systems in general wish to deorbit using atmospheric drag to limit the remaining orbit lifetime to 25 years, as stated by the guidelines. To address this issue, JSC has started a series of studies to investigate the most efficient options for reducing orbit lifetime. In this paper we will review issues raised by the NASA community and the responses that have been made to resolve concerns. Two studies that were designed to minimize costs for postmission disposal will also be discussed in this paper. The first investigates options for disposal maneuvers of upper stages that minimize the cost impact on upper stage development. The second investigates options for high altitude low Earth orbit satellites (e.g. Sun-synchronous spacecraft) that have no significant on-board propulsion.