Orbital Debris Quarterly News 23-3
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National Aeronautics and Space Administration Orbital Debris Quarterly News Volume 23, Issue 3 August 2019 Inside... NASA Technical Standard Process for Limiting Orbital Debris Revision Ratified 2 Testing and Modeling the Demisability of Fiber-Reinforced Plastics 3 The First International Orbital Debris Conference (IOC) is scheduled for December 9–12, An Extended Parametric 2019 at the Sugar Land Marriott Town Square in Sugar Land (greater Houston area), Texas. Study of the Effects of Visit the conference website for registration and logistics information. Large Constellations on the Future Debris https://www.hou.usra.edu/meetings/orbitaldebris2019/ Environment 5 The program and abstracts are available on this website. Register by November 10 for the best Meeting Reports 7 conference rates and by November 21 for hotel reservations at the group rate. Abstracts from the ODQN readers are referred to the conference website for the roster of keynote speakers. NASA HVIT 8 Abstracts from the NASA ODPO 10 ODQN Vol. 23, Two Breakup Events Reported Issue 1&2 Errata 12 The Indian spacecraft Microsat-R (International concomitant rapid orbital decay. A Gabbard plot of this Orbital Debris Designator 2019-006A, U.S. Strategic Command debris cloud is presented in the figure on page 2. Analyst 12 [USSTRATCOM] Space Surveillance Network [SSN] A Centaur V Single-Engine Centaur (SEC) Space Missions/Satellite catalog number 43947), launched on 24 January 2019, rocket variant (International Designator 2018-079B, Box Score 14 was intentionally destroyed in a test of a ground-based, SSN number 43652) fragmented in early April 2019. At direct-ascent Anti-Satellite (ASAT) weapon system at the time of the event the stage was in an approximately 0640 GMT on 27 March 2019. At the time of breakup 35,092 x 8526 km altitude, 12.2° orbit. This Centaur the 740 kg spacecraft was in an approximately 294 x V upper stage is associated with the launch of the 265 km altitude, 96.63° orbit. A total of 101 debris USA 288, or Advanced Extremely High Frequency 4 have entered the public satellite catalog (through object (AEHF 4), spacecraft from the (U.S.) Air Force Eastern 2019-006DF), of which 49 fragments remain on-orbit Test Range on 17 October 2018. The cause of the event as of 15 July 2019. However, over 400 fragments is unknown. No debris have entered the catalog at this A publication of were initially tracked by SSN sensors and cataloging is time, but the ODQN will provide updates should they the NASA Orbital complicated by the low altitude of the event and the become publicly available. ♦ Debris Program Office (ODPO) continued on page 2 Orbital Debris Quarterly News Breakup Events continued from page 1 2500 parent apogee alt. 2000 parent perigee alt. apogee alt. 1500 perigee alt. [km] 1000 altitude 500 0 85 90 95 100 105 110 period [min] The Microsat-R fragments Gabbard plot. Epoch is approximately 5 June 2019. Maximum change in period is on the order of 19 minutes. Maximum change in inclination is on the order of 2°. NASA Technical Standard Process for Limiting Orbital Debris Revision Ratified This revision of the NASA Technical takes steps to limit the quantity and orbital in part, and concurrence has been obtained Standard (NS) 8719.14 is mandated by the formal lifetime of swarms of satellites smaller than from the authors of all suggestions that were NASA acceptance of the revised governing policy 1U CubeSats. not incorporated. document NPR 8715.6 (to revision B) in February 2017 (Procedural Requirements for Limiting Orbital 2. The revised NPR 8715.6 simplifies The Orbital Debris Program Office has Debris and Evaluating the Meteoroid and Orbital the documentation content and delivery prepared the supporting Debris Assessment Debris Environments). Revision NS 8719.14B schedule and the required signatures Software version 3.0 (DAS 3.0) for public release. addresses three key areas: at different stages of certain document DAS 3.0 incorporates the updated requirements deliveries. Such changes have been and reporting details to support compliance 1. Changes bring NS 8719.14 revision incorporated into the revised NS 8719.14B, with the updated standard. The software will be B into full compliance with the current and the required forms have been simplified. released in the near future. U.S. Government (USG) Orbital Debris NS 8719.14 revision B is expected to have a Mitigation Standard Practices (ODMSP). 3. The revision cleans up confusing or retirement date of 25 April 2024 in keeping with With revision B of the standard, NASA now obsolete wording (especially related to active the required periodic update of NPR 8715.6. It disallows long-term disposal options that flight of the shuttle). The revision has included is possible that with the release of updated USG cross through the semi-synchronous MEO the support and contributions of spacecraft ODMSP in the near future, there may be impetus band occupied by the Global Positioning developers across all NASA centers since the to update both the policy and standard earlier System. The revised standard also brings policy itself was in formation. In the final than currently specified. ♦ requirement 4.3-2 into alignment with the draft over 85% of the comments from these USG ODMSP for sizes of allowed debris, and developers have been accepted in whole or 2 https://orbitaldebris.jsc.nasa.gov PROJECT REVIEW Testing and Modeling the Demisability of Fiber-Reinforced Plastics B. GREENE, C. SANCHEZ, AND C. OSTROM samples used and the shape and fiber weave, if fibers, which is consistent with the assumptions A key component of orbital debris mitigation applicable. Each material was exposed to both an made in ORSAT. is the disposal of spacecraft at end of mission. argon plasma with a heat flux of 30 W/cm2 and an CFRP, on the other hand, displayed a high The best post-mission plan from an orbital debris air plasma with a heat flux of 60 - 80 W/cm2 at resistance to thermal demise in this series of mitigation standpoint removes the spacecraft from both the midpoint and the end of the tube. tests, with samples exposed to oxidizing plasma orbit entirely within a reasonable period after the taking up to 4 minutes to fully demise and samples Table 1. Test Sample Descriptions and Quantities end of the spacecraft’s useful life, and atmospheric exposed to non-oxidizing plasma never reaching reentry, whether targeted or through gradual Material Shape Weave Quantity the demise condition within the allotted test orbital decay, is often an inexpensive and effective Aluminum Rod N/A 7 period. means to do this. However, accurate modeling of Different CFRP samples were exposed for Fiberglass Rod Unidirectional (axial) 9 the thermal demise of the spacecraft is required for various amounts of time to measure the mass assessing the casualty risk to people on the ground Kevlar Tube Bi-directional cross-weave 10 loss rate over the course of the demise process. due to randomly falling debris from spacecraft Carbon Fiber Tube Spiral wound 17 The results for the non-oxidizing argon plasma disposed of in such a manner. Carbon Fiber Tube Bi-directional cross-weave 19 condition are shown in Fig. 3. The mass loss rate is As previously reported (ODQN, vol. 22, Carbon Fiber Tube Planar, unwoven 18 initially high and asymptotically approaches zero as issue 3, September 2018, p. 3), the NASA Orbital Carbon Fiber Rod Unidirectional (axial) 10 the polymer matrix is pyrolyzed. Because graphite Debris Program Office (ODPO), in association G10 Plate N/A 3 sublimation will not occur below a surface with the Johnson Space Center’s Structural temperature of 3000 K, without an oxidizer to CFRP-Al Plate Bi-directional cross-weave 2 Engineering Division and the University of Texas honeycomb ablate the carbon fibers they remain indefinitely. (UT) at Austin, tested the demisability of several In an oxidizing atmosphere, the mass loss fiber-reinforced polymer (FRP) materials that have Small objects, such as spacecraft fragments shows a different trend, a bilinear curve, shown become common in modern spacecraft, but whose entering the atmosphere from a ~120 km circular in Fig. 4, as the matrix is first removed through reentry behavior is not currently well-modeled. decay orbit, typically experience a peak heat flux pyrolysis, and then the slower process of graphite For classical aerospace materials like aluminum between 10 and 80 W/cm2 and a dynamic pressure and titanium, the primary mode of demise is of between 0.1 and 10 kPa, depending on the continued on page 4 melting of the material. However, polymer-based shape and ballistic coefficient of the object. materials like FRPs tend to char and chemically The tests focused on CFRP since spacecraft decompose through the process of pyrolysis rather fragments made from these materials have been than melting, invalidating certain assumptions of shown to survive to the ground, contrary to this classical demise model. demise predictions [2]. However, glass fiber- The Phase I test results have prompted reinforced polymer (GFRP) and Kevlar-reinforced development of a new material model for the polymer were also studied. Object Reentry Survival Analysis Tool (ORSAT) Figure 1. Kevlar sample exposed until demise. Test Results that more accurately models the behavior of carbon fiber-reinforced polymer (CFRP) during Of the three classes of FRP tested, Kevlar reentry. demonstrated the highest demisability. The samples demised within 35 seconds of exposure to Experimental Facility and Setup the completely non-oxidizing plasma environment, The materials were tested at the Inductively quickly pyrolyzing both the polymer matrix and Coupled Plasma torch facility at UT Austin. The the Kevlar fibers, as shown in Fig. 1. facility uses a 50 kW induction coil to superheat The fiberglass rods displayed very different up to 1.5 g/s of test gas to approximately 6000 K behavior from that of the Kevlar samples.