Orbital Debris Quarterly News Volume 12, Issue 3 July 2008
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National Aeronautics and Space Administration Orbital Debris Quarterly News Volume 12, Issue 3 July 2008 Inside... The Multiple Fragmentations of Cosmos 2421 Late in the first quarter of 2008, the U.S. Space within a month of the cessation of normal orbit Surveillance Network (SSN) detected a significant maintenance. Bill Rochelle 2 fragmentation of Cosmos 2421 (International Each spacecraft is essentially cylindrical with two Designator 2006-026A, U.S. Satellite Number large solar arrays and a nadir-facing cross-antenna ISS Hand Rail and 29247), which produced approximately 300 (Figure 1). The mass of the vehicle is approximately Extravehicular detectable debris (see ODQN, Vol. 12, Issue 2). Two three metric tons, and the spacecraft recently have Activity Tool more fragmentation events of the same spacecraft demonstrated operational lifetimes of about two Impact Damage 3 during April-June added another 200 or more large years. Normally the debris are relatively short-lived, debris (greater than 5 cm) to the near-Earth space although during the 1980’s three spacecraft (Cosmos’ Haystack Radar environment, once again raising questions about the 1220, 1260, and 1461) were maneuvered into higher Observations of peculiar nature of this satellite class. orbits before undergoing fragmentations, leading to Debris from the Cosmos 2421 is the 50th member of a class of longer-lived debris. Fengyun-1C spacecraft which debuted in 1974 and which normally Some debris from the first fragmentation of Antisatellite Test 7 operate in nearly circular orbits between 400 and Cosmos 2421 on 14 March 2008 were thrown into 450 km at an inclination of 65 degrees. The vehicles orbits with apogees up to 300 km higher than the Abstracts from are often referred to as EORSATs for Electronic pre-event orbit of 400 km by 420 km and perigees as the NASA Orbital Intelligence Ocean Reconnaissance Satellites. Nearly low as 200 km. A little more than six weeks later on half (22 out of 50) of the spacecraft have fragmented 28 April, a new cloud of debris from Cosmos 2421 Debris Program at least once, typically within a few months of the was observed with some fragments now reaching Office 9 end of their primary missions. During the past ten above 900 km at apogee. By early June more than years, four of five E O R S ATs h a v e fragmented 50 cataloged debris from the two events had already Upcoming continued on page 2 Meetings 11 Space Missions and Orbital Box Score 12 A publication of The NASA Orbital Debris Program Office Figure 1. General configuration of Cosmos 2421-class spacecraft. Orbital Debris Quarterly News Cosmos 2421 1000 continued from page 1 900 fallen back to Earth, but more than 300 debris were still in orbit, being 800 Apogee tracked by the U.S. SSN (Figure 2). The third and thus far final 700 Perigee fragmentation event occurred on 9 June when the orbit of the main 600 element of the Cosmos 2421 had decayed slightly to 390 km by 500 415 km. Once again, more than 100 Altitude (km) new debris were observed by the SSN, 400 bringing to 500 or more the assessed total number of debris created as a result of the three fragmentation 300 events. The root cause of the many 200 EORSAT fragmentations remains unknown, and at this time Cosmos 100 2421 is the only member of its class 88 89 90 91 92 93 94 95 96 97 98 still in orbit. ♦ Period (min) Figure 2. More than 300 debris from the first two fragmentations of Cosmos 2421 were still in orbit when the third event occurred on 9 June 2008. William (Bill) C. Rochelle – (15 May 1937 - 7 May 2008) The orbital debris community to ORSAT, the standard NASA re-entry lost a valued colleague on 7 May when survivability analysis tool, and published several Dr. William C. Rochelle passed away conference papers. Bill’s team also collaborated after a year-long illness. with international partners to further enhance Bill, a Texas native, was in predictions for the re-entry survivability of the aerospace industry since the objects. His experience in the aerospace Apollo program. He received a BS industry, including orbital debris re-entry, was in Aerospace Engineering from the vast and irreplaceable. University of Texas at Austin and an Bill was recognized throughout his career MS in Mechanical Engineering from for outstanding service and received many the California Institute of Technology. awards. He recently received the JSC Center His career began as a captain in the Director’s Award for 40 years of exemplary U.S. Army stationed at the Marshall service to NASA. Bill also earned a Lifetime Space Flight Center working on Saturn Achievement Award from the Orbital rockets. During his long career, he Debris Program Office for his outstanding worked in various areas such as arc- contributions to the development of reentry jet testing, Space Shuttle re-entry, physics and risk assessment and for the living and plume impingement for the legacy he leaves in the next generation of International Space Station. Since scientists and engineers he had nurtured and the late 1990s, he had led the Orbital trained. Debris Re-Entry Survivability Team at Both his work and work ethic were of the Lockheed Martin and later at ESCG/ highest standard. He was often the first person Jacobs Technology in support of the in the office and one of the last to go home at NASA Orbital Debris Program Office. night. Outside of being a superb engineer, Bill Under his leadership, the team was also an excellent teacher. His mentoring analyzed re-entries of low Earth orbit benefited many individuals (young and now old) satellites, space telescopes, rocket who work with NASA in a variety of different bodies, Space Shuttle Columbia fields. fragments, and Martian meteorites. Bill will be greatly missed by the Orbital His team completed various updates Debris community. ♦ www.orbitaldebris.jsc.nasa.gov PROJECT REVIEWS International Space Station Hand Rail and Extravehicular Activity Tool Impact Damage J. HYDE, A. DAVIS, AND mm. The approximate crater depth was 1.27 ± mission. At the end of EVA-1, the tool was E. CHRISTIANSEN 0.76 mm and the crater lip height was estimated brought back inside the ISS to be inspected Hypervelocity impact damage sites were to be 0.25 ± 0.13 mm. Since the density of and photographed (Figure 4). A procedure observed on an International Space Station the impacting micrometeoroid (MM) or orbital was developed during the mission to repair (ISS) handrail and an extravehicular activity debris (OD) particle is not known, a diameter the damaged area and the tool was returned to (EVA) tool during the first two shuttle missions of approximately 0.7 mm was calculated service. As with the airlock hand rail mentioned of 2008 (STS-122 and 123). assuming the impactor was aluminum. The above, the EVA D-handle tool is composed During the first spacewalk on damage site has been flagged so that future EVA of 7075-T7351 aluminum material and has the STS-122 (1E), a crater was observed by traffic will not contact the area; avoiding the same cross-sectional dimensions as a hand rail an EVA crewmember on airlock hand rail potential for cuts to EVA crewmember gloves. at the location of the impact. Analysis of the 0506 (Figure 1). The rail material in this The initial spacewalk of STS-123 (1J/A) images provided by the crew indicates that the location is composed of 7075-T7351 aluminum. also resulted in a report of an MMOD crater crater produced by the impact has a diameter of During a subsequent spacewalk on the same on an EVA tool that was exposed to MMOD about 5 mm. In addition to the crater produced mission, high resolution images of the site particle flux in the area of a work site. The by the initial entry of the projectile into the were acquired (Figure 2) for photogrammetric EVA D-handle tool, stored in the Z1 port aluminum D-handle, the impact also produced analysis by the NASA/JSC Image Science and tool caddy (Figure 3), was needed for the backside spall damage on the opposite surface Analysis Group. Results of the analysis provided assembly of the Canadian Special Purpose (Figure 4). Since the density of the impacting an estimated crater diameter of 1.78 ±0.25 Dexterous Manipulator (Dextre) later in the continued on page 4 Impact on airlock HR 0506 Node 1 nadir Airlock Lab stbd fwd Figure 1. Location of MMOD impact on airlock hand rail. Orbital Debris Quarterly News Impact Damage continued from page 3 1.8 mm (0.07 in) diameter crater Figure 2. Detail of MMOD impact on airlock hand rail. continued on page 5 Impact on EVA D-Handle zenith stbd S0 truss segment Z1 port toolbox Service Module Soyuz Figure 3. Location of MMOD impact on EVA D-Handle. www.orbitaldebris.jsc.nasa.gov Impact Damage continued from page 4 particle is not known, a diameter of approx- high occurring to the backside of the handrail. imately 1.1 mm was calculated assuming an The frontside crater was 2.3 mm deep and had aluminum OD particle caused the damage. a raised lip that was 0.9 mm long. The damage A hypervelocity impact test program in Figure 5 is slightly smaller than the impact has been undertaken at the NASA/JSC damage observed on the D-handle EVA tool. Hypervelocity Impact Technology Facility Another result, from test number HITF-8091, (HITF) in Houston, supported by the White is shown in Figure 6. The projectile was a Sands Test Facility in Las Cruces, in an effort 0.7 mm-diameter aluminum sphere impacting to gain understanding of the cratering effects at 6.86 km/s at an impact angle normal to the of small particles.