A publication of The Orbital Debris Program Office NASA Johnson Space Center Houston, Texas 77058 July 1999 Volume 4, Issue 3. Project Reviews The Fate of Upper Stages Placed in Earth Orbit in 1998 N. Johnson years. Of the 89 upper stages, two (believed to near 2,000 km). The orbits of the remaining 86 be in GTO) could not be analyzed due to lack of upper stages were studied to determine their Since orbital debris mitigation guidelines sufficient orbital information and another was longevity. in the U.S. and several other space-faring inserted into an orbit with an uncertain Due to a combination of normal natural nations recommend limiting the orbital lifetime evolution (apogee near 600,000 km and perigee decay and deliberate orbital lifetime reduction of most upper stages, maneuvers, 34 upper an analysis was stages (40%) were no recently performed at Lifetime projections for 1998 upper stages longer in orbit by the NASA JSC to end of 1998. An determine how well additional ten stages operators are Unknown are expected to decay Lifetimes > 25 years complying with the lifetimes (3) during 1999, for a guidelines. During (28) total of 44 (51%). the past ten years For example, 10 (1989-1998), upper Iridium missions in stage mass has been 1998 placed 14 increasing in Earth upper stages in LEO, orbit at the rate of 73 all of which decayed metric tons per year. within one year of A total of 77 launch. This record space missions were was achieved by conducted world- intentionally wide in 1998, reducing the perigees placing 89 upper Decayed during of 11 of the upper stages in Earth orbit, 1998 (34) stages following and approximately Additional decays within spacecraft one out of every three 25 years (24) deployment. will remain in space for more than 25 (Continued on page 2) Inside... Post-Flight Examination ofof thethe STS-95 OrbiterOrbiter................................................................ 4 New and Proposed Orbital Debris Mitigation RegulationsRegulations .................................. 5 Underwater Testing of Space StationStation ImpactImpact Repair Kit BeginsBegins.................. 7 Results from the CoBeam Experiment............................................................................................ 8 1 The Orbital Debris Quarterly News Project Reviews The Fate of Upper Stages Placed in Earth Orbit in 1998, Continued (Continued from page 1) the century mark. Of the higher altitude upper than 25 years. GEO missions, which may leave An estimated two-thirds of the 1998 upper stages stages, 9 with perigees in LEO reside in orbits of upper stages in LEO and/or GTO, represent the will have decayed within 25 years of launch. The more than 25 years lifetime. largest category of long-lived upper stages. remaining 28 upper stages will be evenly divided The study has demonstrated that most Many GEO mission flight profiles could be between LEO and higher altitude orbits. In LEO launch vehicles are being flown in accordance brought into compliance with the 25-year 11 of 14 upper stages will likely remain in orbit with the recommended orbital debris mitigation rule with only modest payload capacity longer than 100 years, while 10 of the 14 higher guidelines. However, one in three upper stages impacts. v altitude upper stages will also probably exceed were found to be in orbits with lifetimes greater New Safety Standard Tracking System R. O’Hara and to facilitate the submission of the required Option. The last section only exists in the orbital debris assessment reports. assessment report if atmospheric reentry is the In an effort to control and minimize future The debris assessments will be evaluated chosen option for spacecraft and upper stage development of orbital debris resulting from using two checklists, one for the Preliminary disposal. These checklists ensure that the assess- space operations, each NASA program or project Design Review (PDR) and one for the Critical ments made by each program are thorough and is required to perform orbital debris assessments Design Review (CDR). Both checklists directly compliant with each standard specfied in NSS in accordance with NASA Safety Standard follow, in outline form, the NSS 1740.14 guide- 1740.14. 1740.14. To better monitor compliance, the JSC lines for producing the PDR and CDR assess- The JSC Orbital Debris Program Office has Orbital Debris Program Office has developed a ments. The checklists are each split into 7 also produced debris assessment software (DAS) new tracking system and database of existing and sections: Brief Background on Program and to aid programs in completing their debris proposed NASA programs. The database cur- Program Management, Description of Design assessment. Both NSS 1740.14 and DAS can be rently consists of 82 programs, including some and Operations Factors, Assessment of Debris downloaded from the NASA orbital debris web- international projects in which NASA partici- Released During Normal Operations, Assess- site at www.orbitaldebris.jsc.nasa.gov. It is pates. Information, such as dates for the Prelimi- ment of Orbital Debris Generated by Explosions critical for every program to perform the assess- nary and Critical Design Reviews, the orbital and Intentional Breakups, Assessment of Debris ment and ensure compliance with NASA's safety debris assessment status for both, the launch Generated by On-Orbit Collisions, Description standards for the safety of that mission and date, and the spacecraft and upper stage disposal of Postmission Disposal Procedures and Sys- missions to come. v options, are included in the database. Each tems, and Assessment of Survival of Debris from program office is contacted to verify data entries the Postmission Disposal Atmospheric Reentry JSC Team Visits KSC for Exchange on Space Shuttle Post-Flight Inspections J. Theall wing, the flexible reusable surface insulation adverse effects during reentry from a small (FRSI) on the exterior of the payload bay doors, particle penetration in the RCC. In late April a team from the NASA Orbital and the radiators were demonstrated. In return, the JSC team made presentations Debris Program Office at JSC traveled to the Of particular interest was the tool designed to two different shifts of KSC personnel, provid- Kennedy Space Center (KSC) for a technical and developed at KSC to illuminate the window ing an overview of the NASA Orbital Debris exchange on the hazards of orbital debris to thermal panes for identification of even tiny Program, methods used to define and to monitor Space Shuttles and the benefit of Orbiter post- impact features. On average one of the thermal the orbital debris environment, and engineering flight inspections. The Orbiter Processing Facil- panes on the eight main windows in the crew and operational steps taken to reduce the threat ity (OPF) staff escorted the JSC team on a cabin must be replaced after each flight due to of orbital debris and meteoroids to the Space walk-around of a Space Shuttle being prepared impacts by tiny orbital debris and meteoroids. Shuttle. v for another flight. The techniques used when The JSC team also was able to view the process inspecting the windows, the reinforced carbon- for upgrading the insulation behind the leading carbon (RCC) coating of the leading edge of the edge of the wing to minimize the possible (Continued on page 3) Visit the New NASA Johnson Space Center Orbital Debris Website http://www.orbitaldebris.jsc.nasa.gov 2 The Orbital Debris Quarterly News Project Reviews JSC Team Visits KSC for Exchange on Space Shuttle Post-Flight Inspections, Continued (Continued from page 2) Figure 1. A probe and adhesive tape are used to retrieve residue inside a crater in the FRSI caused by an orbital debris or meteoroid impact. Figure 2. A magnifier with light source is used to examine small impact regions on a thermal pane of the Space Shuttle. 3 The Orbital Debris Quarterly News Project Reviews Post-Flight Examination of the STS-95 Orbiter J. Kerr minum, 43% were paint, and 14% were stainless Inspections of the FRSI found two new steel. impact sites greater than 1 mm in extent: one During October-November 1998, the Space Examination of the radiators led to the meteoroid (1.6 mm in diameter) and one orbital Shuttle Discovery spent nearly 9 days in a low discovery of three impact features with a mini- debris (1.8 mm diameter aluminum). No damage altitude (574 km), low inclination (28.5 deg) mum 1.0 mm damage diameter. All three sites was identified on the RCC surfaces. orbit for the research in life sciences and John yielded sufficient residue to determine the nature Post-flight inspections of Space Shuttle Glenn’s return to space. In April 1999 a report of the impactor. Two of the impactors were orbiters continue to produce valuable data on the sponsored by the NASA Orbital Debris Program orbital debris (0.1 mm diameter stainless steel natural and artificial particulate environment in Office summarized the orbital debris and mi- and a 0.4 mm diameter paint flake) and one low Earth orbit. A new, more comprehensive crometeoroid damage discovered during post- impactor was a 0.5 mm diameter meteorite. Two assessment of these mission data has been re- flight inspections (STS-95 Meteoroid/Orbital of the three impacts created face sheet perfora- cently initiated at JSC with preliminary results Debris Impact Damage Analysis, JSC-28497, tions including a rare perforation of the rear anticipated in 1999. v Justin Kerr and Ronald Bernhard). surface of a deployed radiator. The primary orbiter surface areas examined included the crew compartment windows (3.6 m2), the reinforced carbon-carbon (RCC) leading edge of the wings (41 m2), the flexible reusable surface insulation (FRSI) on the exterior of the payload bay doors (40m2), and the radiator panels (117 m2). In all, 45 impact sites were examined by tape pull, dental mold, or wooden probe extraction techniques.