ODQN 9-1 95Pt for PDF.Pub

The www.orbitaldebris.jsc.nasa.gov Volume 9, Issue 1 January 2005 A publication of Modeling and Monitoring the Decay The NASA Orbital of NASA Satellites Debris Program Office D. WHITLOCK predictions are made by the SSN and distributed by at In February 2002, NASA Headquarters directed the NASA Orbital Debris Program Office to relevant that greater attention be given to the reentry of orbit- NASA offices. Johnson Space Center ing NASA spacecraft and rocket bodies. NASA PROP3D uses an initial element set and ballistic Houston, TX, USA Policy Directive 8710.3B1 charges the Orbital Debris coefficient as primary inputs and then propagates Program Office, in support of the Director of the these orbital elements forward (in one-day steps) until NASA Johnson Space Center, to maintain a list of object reentry (perigee altitude less than 95 km). The predicted reentry dates for all NASA spacecraft and object’s area-to-mass ratio (A/M) directly affects the their associated orbital stages and to advise appropri- ballistic coefficient and may either be defined by the INSIDE… ate NASA personnel during the final stages of orbital user or estimated using software developed specifi- decay. A process, which begins before launch and cally for this task by NASA. This software uses a Haystack Orbital which includes cooperation with the U.S. Space curve-fit of the semi-major axis history (using a least Debris Radar Surveillance Network (SSN), has been developed to squares filter) to derive an observed A/M for any model and to monitor the orbital decay of NASA Earth-orbiting object. Measurements space objects. NASA’s PROP3D orbit propagator is The assessment of object decay begins during the Update ...................... 3 the principal tool used to predict orbital lifetimes in design phase for each NASA sponsored project. NSS the period prior to 60 days before reentry. PROP3D 1740.142 requires every project to provide a prelimi- Varying Solar Flux accounts for complex factors such as the Sun and nary Orbital Debris Assessment report at the time of Models and their Moon’s gravitational effects, solar activity, J2/J4 the preliminary design review, with a final report Effect on the Future effects, atmospheric drag, and solar radiation pressure. submitted no later than 45 days prior to the critical One of the most difficult and often most important design review. It is during this assessment that the Debris Environment parameters to estimate accurately is an object’s project is required to demonstrate that the spacecraft, Projection ................. 4 ballistic coefficient. In the final 60 days before rocket body, and any mission-related debris stay in reentry, emphasis is placed on the more accurate orbit no longer than 25 years after completion of ST9 Solar Sail—A numerical tools of the SSN. During a satellite’s final mission. Each project also provides an A/M for each Potential Meteoroid four days in space, specific reentry time and location object for the purpose of determining its lifetime. A/M = 9.29E-3 m^2/kg NASA provides 3500 and Orbital Debris Debris Assess- Sensor........................ 6 3300 Actual ment Software to the project for Space Missions and 3100 Curve Fit assistance in Orbital Box Score .... 9 lifetime calcula- 2900 tion. After launch, Meeting Report........ 9 2700 a reentry date 2500 can be estimated Satellite using the latest Population..............10 2300 available ephemeris from the 2100 SSN with Semimajor Axis (in km altitude) km Axis (in Semimajor PROP3D and an Visit the NASA 1900 A/M taken from Orbital Debris Program 1700 the assessment Office Website report or from an 1500 internal database. at Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 Dec-03 Jan-04 Feb-04 Once multiple element sets are www.orbitaldebris. Epoch available after Figure 1. Least squares curve-fit of semi-major axis for the MER-B, Delta 2 rocket body (27851, 2 launch, the A/M jsc.nasa.gov estimated A/M = 9.29E-3 m /kg). Continued on page 2 1 The Orbital Debris Quarterly News Decay of NASA Satellites Actual Reentry: 7/26/2004 Continued from page 1 3500 (and consequently the ballistic coefficient) can be better estimated. Twice per year, the Orbital Debris Program Office estimates 3000 reentry for all of the near 200 NASA space Actual objects. Figure 1 displays a semi-major axis Propagation curve-fit for a Delta 2 rocket body associated 2500 with the Mars Exploration Rover (B) launched in July 2003. For this example, the 2000 curve-fit included ephemeris data through 30 January 2003. The curve-fit estimates an A/ M of 0.00929 m2/kg. Propagating the last 1500 ephemeredes forward (using this A/M) a reentry prediction of 28 July 2004 is shown 1000 in Figure 2. Actual reentry was 26 July 2004. For some mission profiles, the rocket Semimajor Axis (in km altitude) body may reenter within 60 days of launch. 500 While PROP3D can assist in determining whether or not this is the case, other numerical tools from the SSN are used to determine 0 the most accurate reentry epoch for all Jun-03 Aug-03 Oct-03 Dec-03 Feb-04 Apr-04 Jun-04 Aug-04 objects within 60 days of reentry. These Epoch tools are also used during the final four days, Figure 2. Propagation of semi-major axis for MER-B, Delta 2 rocket body (27851). Predicted when the SSN provides NASA a predicted reentry: 7/28/2004, Actual reentry: 7/26/2004. reentry epoch and location based upon the latest observations. These predictions are 1.Policy to Limit Orbital Debris Generation, 2. Guidelines and Assessment Procedures for continuously updated until final atmospheric NASA Program Directive 8710.3B, 29 May Limiting Orbital Debris, NASA Safety reentry. 1997, revised 28 April 2004. Standard 1740.14, 1 August 1995. ♦ Recent Satellite Breakups Another Proton Block DM auxiliary namic event occurred in early October, when Finally, on 11 December an Atlas V R/B motor experienced a fragmentation on 29 the Molniya 1-82 (1991-53A, U.S. Satellite (2003-20B, U.S. Satellite Number 27812) October 2004. The auxiliary motor was one Number 21630) spacecraft experienced a experienced an aerodynamic breakup during of two used for the Cosmos 2392 mission similar fragmentation. At the time of the final atmospheric reentry. Perigee at the which was launched in 2002. The event, the perigee of the satellite was time of the event was near 90 km with a very International Designator of the parent object approximately 80 km. The parent and all high apogee, over 10,000 km. Although no is 2002-37F, with corresponding U.S. debris decayed within days, and there were piece count was available, any debris would Satellite Number 27475. This is the 31st no cataloged debris as a result of this event. have been very short lived. ♦ event for this class, and the second such event in 2004. The 55 kg motor was in an orbit of approximately 235 km by 840 km, NASA Orbital Debris Program Office with an inclination of 63.6º. No debris were officially cataloged from the breakup, Hosting IADC Website although more than 60 fragments were The NASA Orbital Debris Program search activities between member space detected by the U.S. Space Surveillance Office became the host sponsor of the Inter- agencies, to facilitate opportunities for coop- Network. This was the first auxiliary motor Agency Space Debris Coordination Commit- eration in space debris research, to review launched after 1996 to have experienced a tee (IADC) website, www.iadc-online.org, in the progress of ongoing cooperative activi- fragmentation. December 2004. ties and to identify debris mitigation options. There have been three recent The IADC is an international govern- The IADC comprises a Steering Group fragmentation events during the final stages ment-level forum for the worldwide coordi- and four specified Working Groups. Topics of atmospheric decay from highly elliptical nation of activities related to the issues of addressed by these four groups include orbits. In mid-August, the Cosmos 1030 man-made and natural debris in space. The measurements (WG1), environment and da- spacecraft (1978-83A, U.S. Satellite members of IADC are the space agencies tabase (WG2), protection (WG3) and mitiga- Number 11015) experienced a breakup from 10 countries (China, France, Germany, tion (WG4). when its perigee decayed below 100 km. India, Italy, Japan, Russian Federation, This site provides information to the There was one piece of cataloged debris Ukraine, United Kingdom, and the United public about the IADC, its member agencies (U.S. Satellite Number 28401) from this States), as well as the European Space and past and current debris related activities. event. Both the parent object and the Agency. Furthermore, it provides links for communi- cataloged debris object decayed within a The primary purpose of the IADC is to cation between the IADC member agencies week of the breakup. A second aerody- exchange information on space debris re- and the associated organizations. ♦ 2 www.orbitaldebris.jsc.nasa.gov Haystack Orbital Debris Radar Measurements Update E. STANSBERY, J. FOSTER, & C. STOKELY Haystack Process Improvements The Haystack radar began collecting orbital debris data for NASA in August 1990. Haystack and the Haystack Auxiliary (HAX) radar (which became operational in 1994) have been NASA’s primary source of statistical data on the orbital debris population as small as a few millimeters in diame- ter. The radar and the associated data processing have evolved during the 14 years that NASA has been collecting debris data. NASA’s ambitious plan in 1990 called for collecting more than 1000 hours of data per year for at least a complete solar cycle.

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