The www.orbitaldebris.jsc.nasa.gov

Volume 8, Issue 1 January 2004

A publication of New NASA Policy for Limiting Orbital Debris

The NASA Orbital Generation Debris Program Office On 27 January 2003, NASA Administrator Sean (5) maintaining a list of predicted reentry dates for O’Keefe signed NASA Policy Directive (PD) NASA spacecraft and upper stages, at 8710.3A, the latest revision in NASA’s 10-year-old (6) providing technical and policy assistance to all policy designed to curtail the growth of the orbital NASA headquarters offices and centers, and Johnson Space Center debris population. The new policy recognizes the (7) promoting the adoption and use of international Houston, TX, USA growing importance of orbital debris mitigation, both orbital debris mitigation guidelines.” nationally and internationally, and a need to expand For the first time, NASA orbital debris policy the responsibilities of various organizations within addresses the issue of U.S. Government coordination NASA. Ten organizations or positions within NASA prior to the reentry, controlled or uncontrolled, of are now assigned explicit orbital debris mitigation spacecraft and upper stages employed on NASA mis- duties, in contrast to only four organizations or posi- sions. A copy of NPD 8710.3A can be obtained via INSIDE… tions cited in the previous policy. the Orbital Debris Program Office website at www. The Orbital Debris Program Office, in support of orbitaldebris.jsc.nasa.gov. the Director of the Lyndon B. Johnson Space Center, Orbital Debris Work is now underway on a related revision to is responsible for Website Update ....2 NASA Safety Standard 1740.14, Guidelines and As- “(1) developing, maintaining, and updating orbital sessment Procedures for Limiting Orbital Debris, first Reentry Survivability debris environment models, issued in 1995. The new standard will reflect im- (2) assisting space program/project managers in tech- provements in both the technical foundation of the Analysis of the nical debris assessments, standard and the assessment process. Where appro- TRMM Spacecraft ..4 (3) providing technical reviews of orbital debris as- priate, minor changes will also be incorporated to en- sessment reports, sure that the standard is consistent with the latest na- (4) reviewing end-of-mission plans for NASA space- tional and international orbital debris mitigation Growth in the craft, guidelines. Number of SSN Tracked Orbital Satellite Fragmentations in 2003 Objects ...... 7 In a further indication that world-wide before passivation measures were adopted in the passivation measures are apparently having a positive 1990’s. effect, satellite breakup activity in 2003 was minor The first event occurred on 21 February and Results from the and limited to two pre-reentry events, three small involved an ullage motor from the Cosmos 2109-2111 GEO Debris Survey Soviet propulsion units launched during 1987-1990, mission (1990-110G, U.S. Satellite Number 21012). and a low altitude intentional breakup. Meanwhile, Only a few debris were detected with this breakup. with MODEST ...... 8 the Hubble Space Telescope and non-operational The second event, which was associated with the French and American satellites each released an Cosmos 1883-1885 mission (1987-079H, U.S. Space Missions unexpected piece of debris in classical anomalous Satellite Number 18375), occurred on 23 April and and Orbital events. produced about three dozen, short-lived debris. In January 2003, the Molniya 1-66 rocket body Finally, an ullage motor from the Cosmos 1970-1972 Box Score ...... 14 (1985-103D, U.S. Satellite Number 16223) and mission (1988-085F, U.S. Satellite Number 19535) Cosmos 1849 (1987-048A, U.S. Satellite Number apparently broke-up twice between 4 and 6 August. 18083) both experienced minor breakups during the The first event again produced only a few dozen final stages of catastrophic orbital decay from highly debris, but the second event generated up to 200 new elliptical orbits with perigees less than 120 km. In debris. Visit the NASA both events all debris created apparently decayed On 9 December the Russian Cosmos 2399 Orbital Debris Program within only a few days. spacecraft was intentionally destroyed at an altitude of Between February and August 2003, only 190 km. Only 21 debris were identified by the Office Website fragmentations of three Proton Block DM SOZ ullage SSN, and these were short-lived. Cosmos 2399 was at motors, all from former Soviet navigation satellite the seventh of a series of spacecraft which began missions, were detected by the U.S. Space flights in 1989 and which are disposed of destructively www.orbitaldebris. Surveillance Network (SSN). All objects were in at very low altitudes at the end of mission. jsc.nasa.gov elliptical orbits with perigees of 645-755 km and In August two anomalous events, i.e., small apogees near 18,500-18,800 km and were launched Continued on page 2 1

The Orbital Debris Quarterly News NEWS Orbital Debris Satellite Fragmentations in 2003 Website Update Continued from page 1 the 5-meter-long antennas extending from The NASA Orbital Debris Program number of debris released at low velocities, SARA. One hypothesis is that one of the Office website, www.orbitaldebris.jsc.nasa. were detected by the SSN. A piece of debris, antennas was severed by the impact of a gov, has been redesigned with a stylish estimated to be about 5 cm in diameter, was small meteoroid or orbital debris. Long, thin layout and new navigation structure. All apparently liberated from the Hubble Space antennas on other spacecraft have suffered pages now contain a “flyover” menu system Telescope (HST) (1990-037B, U.S. Satellite similar fates. The mean altitude of SARA at for easy traversal. The pages contain Number 20580) on 5 August at an altitude of the time of the event was 730 km. Like the graphical indicators of where you are and about 575 km. The nature of the debris HST debris, the SARA debris is decaying at a quick links to related pages within the sub- remains unknown, but it was initially faster rate than its parent. section. Beside the new look and feel, the decaying at a faster rate than HST. Finally, on 25 November a small piece original content has been updated and new The French satellite SARA (1991-051E, came off the NOAA 7 spacecraft (1981- content has been added. U.S. Satellite Number 21578) was the subject 059A, U.S. Satellite Number 12553) at an One of the new additions to the website of the second anomalous event in August. altitude of about 835 km. The spacecraft has is the Photo Gallery. Many photos relating The object, later cataloged as 1991-050H (U. previously released unexpected small debris, to orbital debris have been collected and S. Satellite Number 28065), is larger than the the first time in July 1993. made available. Another component added piece from HST and might be part of one of to the site is the Important Reference Docu- ments section, which contains publicly 2003 NASA Orbital Debris Colloquium available documents related to orbital debris On 4 and 5 November 2003, the third 1740.14, Guidelines and Assessment and its research. Also check out the new annual NASA Orbital Debris Colloquium, Procedures for Limiting Orbital Debris. The Reentry section for information on the cur- hosted this year by the Orbital Debris latter was reviewed in detail to permit agency rent orbital debris work going on in this Program Office, was held near the Lyndon B. personnel an opportunity to ask questions area. Johnson Space Center in Houston to address about proposed changes and to offer other The Orbital Debris Quarterly News has a wide variety of issues related to orbital improvements to the Standard. Reports on also been given a new design layout and is debris. Attendees included representatives orbital debris mitigation efforts at GSFC, incorporated in this January 2004 issue. from NASA Headquarters, the Goddard KSC, and JPL were also presented, as was a Going to the Orbital Debris Quarterly News Space Flight Center (GSFC), the Marshall special summary of the Columbia Accident page of the website will give you access to Space Flight Center (MSFC), the Kennedy Investigation Board’s final report with this issue as well as all other Orbital Debris Space Center (KSC), and the Jet Propulsion particular emphasis on reentry risk assess- Quarterly News issues that have been pub- Laboratory (JPL), as well as JSC. ment. Finally, plans for the development and lished. All issues are available for viewing Two of the primary topics discussed release of NASA’s Debris Assessment or downloading in Abode PDF format. Also were the new NASA policy directive on Software (DAS), Version 2.0, were de- provided for user friendliness are issue orbital debris limitation (NPD 8710.3A) and scribed. highlights that are displayed as the user the draft revision of NASA Safety Standard positions their mouse over the specific issue. If you would like to be notified when the Chandra Observatory Possibly Hit by next issue is available, please go to the Orbital Debris Quarterly News section of the Small Particle website and fill out the subscription form. The Chandra X-Ray Observatory (CXO) bance was automatically corrected, and no was probably a meteoroid, possibly a Leonid was apparently hit by a small particle on 15 residual effects have been detected. CXO meteoroid, rather than orbital debris. CXO November at approximately 1554 UTC. A orbits the Earth in a highly elliptical orbit of was launched inside Space Shuttle Columbia minor disturbance in the spacecraft’s point- about 25,000 km by 125,000 km. At the time (STS-93) on 23 July 1999. ing stability was recorded during a period of the event, the spacecraft was at an altitude between scientific observations. The distur- of ~52,000 km, suggesting that the particle John R. Gabbard The orbital debris community lost one of The U.S. Space Surveillance Network still to curtail the growth of the orbital debris its most venerable and well-respected uses another of John’s innovations: the environment during the past twenty years members in October with the passing of John Gabbard system of orbit type classification. than any other action. R. Gabbard at the age of 82. While working John also made many noteworthy After a distinguished career as a U.S. for the Analysis Directorate of the former discoveries during his long aerospace career. civil servant, John continued his work for NORAD/ADCOM in Colorado Springs, One of the most important involved the post- several years with Teledyne Brown Engi- Colorado, in the 1970’s, John developed the mission explosions of Delta launch vehicle neering, helping to educate a new generation now-famous Gabbard diagram which depicts second stages. His identification of a series of space analysts. John will long be remem- the apogee, perigee, and period of debris of major fragmentations associated with bered by his many friends not only for his from a satellite fragmentation. Such dia- these launch vehicles led to the adoption, first ability to interpret data and to see patterns grams are extremely useful tools in identify- in the U.S. and later around the world, of a where others saw none, but also for his ing objects from an explosive event and in passivation policy for all spacecraft and genuine good nature and willingness to help understanding characteristics of the event. launch vehicles. This policy has done more all. 2 www.orbitaldebris.jsc.nasa.gov PROJECT REVIEWS Hypervelocity Impact Survey of the Multi-Purpose Logistics Module (MPLM) J. HYDE, R. BERNHARD, & damage to the Meteoroid and Debris Protec- near the pressure shell. Figure 1 depicts the E. CHRISTIANSEN tion System (MDPS) of the MPLM through typical layout of an MDPS panel in the cylin- The International Space Station (ISS) observations, data collection and analysis. der region. program has manifested a Multi-Purpose Lo- Through five missions, there have been The orientation of the MPLM when at- gistics Module (MPLM) on five launch pack- two perforations (i.e., complete penetrations) tached to ISS Node 1 is shown in Figure 2. ages since 2001, with another flight sched- of the aluminum outer “bumper” wall of the The MPLM keel trunnion is oriented in the uled for the STS-114 mission. The MPLM MDPS and twenty-four HVI craters. The risk ISS starboard direction, while the port trun- has been deployed each time on the nadir of bumper perforation for a typical MPLM nions face in the forward (velocity) direction docking port of Node 1 by the Space Shuttle. mission was estimated to be 55% by the in the ISS frame of reference. The keel trun- Flight module 1 (Leonardo) and flight mod- BUMPER risk assessment code (more infor- nion will face the bottom of the Orbiter pay- ule 2 (Raffaello) have accumulated about 700 mation on BUMPER code can be found in load bay (PLB) when the MPLM is carried as hours of low Earth orbit (LEO) exposure ODQN Vol. 4, Iss. 3). Observed damage to cargo in the PLB. time on the ISS. This article documents the MPLM (i.e., 1 outer wall perforation every The images in Figure 3 show the front results of an on-going post-flight campaign 2.5 flights) and the distribution of crater dam- and back side views of the bumper perfora- that identifies hypervelocity impact (HVI) age match the BUMPER code predictions. tion that occurred during the initial flight of Forty MDPS panels protect the cylinder the MPLM. The maximum diameter of the region of the MPLM. Each MDPS panel crater lip was 2.45 mm and the diameter of consists of a 0.8 mm thick aluminum alloy, the hole was 1.44 mm. The MDPS panel was also called an external “bumper”, that is removed and the MLI blanket below the im- mounted 127.6 mm away from the 3.0 mm pact point was inspected, but no damage or thick aluminum alloy pressure shell. A blan- debris was found on the blanket itself. Sam- ket of multi-layer insulation (MLI) is located See MPLM on page 13

Figure 1. The typical layout of an MDPS panel in the cylinder region.

Figure 3. The front and back side views of the bumper perforation that occurred during the initial flight of the MPLM.

Port Trunnions

MDPS Panels (2 of 40)

Keel Trunnion

Figure 2. The orientation of the MPLM when attached to ISS Node 1. Figure 4. SEM output images and EDX spectra for samples collected from the bumper perforation. 3 The Orbital Debris Quarterly News Reentry Survivability Analysis of the Tropical Rainfall Measuring Mission (TRMM) Spacecraft R. SMITH, J. DOBARCO-OTERO, J. MARICHALAR, & W. ROCHELLE The joint NASA/Japanese National Space Development Agency (NASDA) spacecraft was launched in November 1997 from Tanegashima, Japan. The United States is responsible for the satellite bus, four instrument sensors, and satellite operation through NASA Goddard Space Flight Center (GSFC), Greenbelt, MD. Japan is responsible for the largest instrument (Precipitation Radar) and was responsible for the launch with a Japanese H-II launch vehicle. A sketch of the TRMM with the solar array deployed is shown in Figure 1, showing location of the five instruments: Precipitation Radar (PR), TRMM Microwave Imager (TMI), Visible and Infrared Scanner (VIRS), Clouds and Earth’s Radiant Energy System (CERES), and Lightning Imaging Sensor (LIS). The objective of the TRMM Figure 1. TRMM Spacecraft with solar arrays deployed. spacecraft is to measure the amount and distribution of rainfall in tropical and near- 90 tropical areas of the Earth, using the data to predict climatic changes on a global scale. 80 The TRMM was launched in a 350 km 70 altitude, 35º inclination circular orbit; however, nearly three years later, it was 60 boosted to a 402.5 km altitude as a means of extending the mission life. Eventually, the 50 orbital decay of the TRMM spacecraft will cause it to reenter the Earth’s atmosphere, 40 resulting in break-up and demise of most of the spacecraft components. However, due to 30 the size, mass and material properties of Demise Altitude (km) some of the components, there is a possibility 20 that some of these objects will survive the atmospheric reentry and pose a safety risk to 10 the ground population. In order to assess compliance with the 0 NASA Safety Standard 1740.14 Guideline 7- 0 200 400 600 800 1000 1200 1, several reentry survivability analyses were Downrange from Breakup (km) performed for the TRMM. The initial analysis was performed in early 1999 using Figure 2. Demise altitude vs. downrange for all TRMM components. the Miniature Object Reentry Survival The basic assumptions of this final = 3.7 m, and height = 3.0 m. Other Analysis Tool (MORSAT), with only 8 TRMM analysis include an orbital decay assumptions included an initial surface TRMM components. This analysis was entry (uncontrolled), starting at an entry temperature of 300 K for all components, an updated in early 2001 using the ORSAT code interface altitude of 122 km. The initial average oxidation efficiency of 0.5, and a with 35 TRMM components. The final and breakup of the spacecraft was assumed to surface emissivity of most materials of 0.3. most complete analysis was performed in late occur at 78 km. Below this break-up altitude, In some cases in which a component demised 2002 using the ORSAT code with over 200 the primary components were assumed to at lower altitude (below about 60 km) or TRMM components, representing over 91% split from the parent body and enter survived with a high demise factor (absorbed of the total mass of the spacecraft. This last separately. In a number of cases, further heat divided by heat of ablation) of over reentry survivability analysis considered all fragmentation of subcomponents occurred. 90%, a parametric analysis was considered in five instruments and included all components The parent body of the TRMM was which the initial temperature, oxidation of the structural subsystem, electrical assumed to have a mass of 2620 kg, with subsystem, and high-gain antenna. box-like dimensions of length = 5.1 m, width Continued on page 5

4 www.orbitaldebris.jsc.nasa.gov

Reentry Survivability Analysis of TRMM Continued from page 4 high demise factor were evaluated in a Figure 2 shows the demise altitude efficiency, and emissivity were varied from parametric analysis in which initial plotted vs. downrange for all the TRMM the nominal values. temperature, surface oxidation, and/or components modeled by ORSAT. There is a Ten nodes were used in the 1-D heat surface emissivity were allowed to vary near linear variation of demise altitude vs. conduction analysis for spheres and cylinders slightly from the nominal values. This downrange until about 60 km, when some for nearly all TRMM components. A lumped analysis resulted in four out of these five scatter occurs as some of the components mass model was used for all boxes and flat objects demising. As a result, the final begin to survive. The seven surviving plates. The 1976 U. S. Standard Atmosphere results showed seven components (all made components at impact (altitude = zero) are model was used for all components. Fifteen of titanium with a high melt temperature of also shown on this figure, with a range different materials were used in the analysis 1943 K) survived, or 12 components, between 534 km and 1010 km (or footprint for the approximately 210 components counting multiple components of the same length of 476 km) for the surviving evaluated. The point of object demise is type, survived. This resulted in a total debris components. A total mass of 112 kg was assumed to occur in ORSAT once the total casualty area of 11.3 m2. Using the 35º-orbit obtained for all surviving components, or a heat absorbed (net heating rate integrated inclination with this debris casualty area and 4.3% surviving mass compared to the over time, multiplied by its surface area) a year of reentry for the orbital decay of original mass of 2620 kg for the TRMM becomes greater than the heat of ablation of 2009, a risk of 1:4530 was obtained. If the spacecraft. The results of this analysis were the object. TRMM spacecraft were to reenter from submitted to NASA GSFC to aid in assessing Five TRMM components that either orbital decay in 2006, the risk would be compliance with the NASA Safety Standard demised at a low altitude or survived with a slightly lower at 1:4600. for orbital debris. Cube – The LEGEND Collision Probabilities Evaluation Model J.-C. LIOU objects. This is a statistical approach based lated based on their orbital elements at that LEGEND, a LEO-to-GEO Environment on random sampling in the physical space instance. The cube inside which each object Debris model, is a new three-dimensional where collision is possible. It has been ap- is located is identified. When there are two orbital debris evolutionary model developed plied to estimate collisions between asteroids objects within the same cube, the collision by the NASA Orbital Debris Program Office and comets [2, 4, 5, 6], collisions between rate is determined by the same spatial density at the Johnson Space Center. Since collisions Jovian satellites [3], and collisions between approach developed by Kessler [3]. On a mi- are likely to dominate the future debris envi- artificial satellites [7]. However, there are croscopic scale, this is identical to the kinetic ronment, it is critical for LEGEND to have a some systems that violate one or both of the theory of gas approach. On a macroscopic good model to evaluate collision probabilities assumptions. Examples include asteroids scale, the orbital elements of objects are de- among objects from LEO to GEO. The re- near mean motion resonances (non-random termined from the orbital evolution simula- quirements for such a model include: (1) a Ω, ω, and λ; fast changing eccentricity and/or tions. No assumptions regarding either con- three-dimensional model capable of captur- inclination), comets (non-random Ω and/or stant (a, e, i) or uniform (Ω, ω, λ) are needed. ing collision characteristics among objects ω), and objects under strong dissipative Note that the only objects selected for colli- with uniform and non-uniform distributions forces (fast changing a and e). sion evaluation are those within the same in orbital element and in precessing rate, (2) With the help of modern computers, it is cube. For those identified as the only object a model capable of handling a system of sev- now possible to perform numerical simula- in a cube, they are not processed any further. eral hundred thousand objects, and (3) a tions on the orbital evolution of an N-body This is a fast and efficient way of performing model with manageable computer speed and system. Therefore, there is a need for a colli- pair-wise comparisons. The computation space. sion model that can work with an orbital evo- time of this approach increases with N, rather 2 The classical way to evaluate collision lution simulation to utilize the updated infor- than N , for an N-body system. This ap- probabilities between two orbiting objects mation (new objects, decayed objects, orbital proach can be coupled with any numerical was pioneered by Öpik [1]. This method was elements) as the system evolves in time. The simulations of the orbital evolution of objects later generalized by Wetherill [2], Kessler Cube approach is designed to accomplish this (orbital debris, asteroids, comets, Kuiper Belt [3], and Greenberg [4] to allow for non- objective. The basic assumption of the ap- objects, planetesimals, etc.) to evaluate the circular orbits for the objects involved and to proach is that the long-term collision charac- long-term collision probability as the system handle singularity problems associated with teristics of a system can be represented by evolves. At every integration time step, one certain close encounter geometries. The fun- evaluating the collision probabilities among needs to identify multi-object cubes and de- damental assumptions of this approach are objects at numerous instances (snapshots) termine the collision rate of each pair of ob- (1) the semimajor axis, eccentricity, and in- during the simulation. Instead of the classical jects. A random number is then drawn to clination (a, e, i, respectively) of each object uniform sampling in space approach, this is a compare with the probability to determine remain constant, and (2) the right ascension uniform sampling in time approach. whether or not a collision would occur. As a of the ascending node, argument of perigee, The procedure to evaluate collision standard statistical sampling technique, more and mean longitude (Ω, ω, λ, respectively) of probabilities among objects at each instance snapshots, or smaller time step between snap- each object are distributed randomly between in time is straightforward. At each snapshot shots, are preferred. The identification of ob- 0 and 2π. Based on these assumptions, all the three-dimensional space is divided into jects with non-zero collision rate and the possible close encounter geometries between many elements (cubes). The cube dimension computation time of collision probability any two orbiting objects can be sampled ran- is characterized by the short-period perturba- should be small compared with the orbital domly or uniformly to obtain the long-term tions on the positions of the objects. The po- average collision probability between the two sition and velocity of each object are calcu- Continued on page 6 5 The Orbital Debris Quarterly News Cube – The LEGEND Collision Probabilities Evaluation Model Continued from page 5 all, the Cube predictions are consistent with “uniform sampling in time” approach agrees integration time of an N-body system. There- asteroids/comets/satellites collision probabili- with the classical “uniform sampling in fore, the integration time step should be used ties calculated by various authors using space” approach. The Cube approach is also to evaluate collision probabilities. In addi- Öpik’s approach [8]. For LEO debris com- capable of predicting the long-term collision tion, the cubes have to be small enough to parison, the Cube predictions agree well with probabilities among orbiting objects in a gen- capture the characteristics of the true colli- results using Kessler’s method for objects eral (non- Öpik) system. This fast and reli- sion nature of the system. In general, a di- with regular orbits (no singularities). The able model is a critical component in LEG- mension of 1% or less of the average semi- Cube model has no problems dealing with END to predict the future orbital debris envi- major axis of objects in the system is suffi- LEO objects with irregular orbits ronment. cient. A time step of 5 days and 10 × 10 × 10 (overlapping at perigee or apogee) that can- Reference: km3 cubes are the default setup in LEGEND. not be calculated using Kessler’s method. In [1] Öpik E.J. (1951) Proc. Royal Irsh Acad., In the extreme case where the cube is as big addition, we have applied the Cube model to 54A, 164-199. [2] Wetherill G.W. (1967) as the whole system, the Cube approach two objects in mean motion resonance (a JGR, 72, 2429-2444. [3] Kessler D.J. (1981) mimics a simple particle-in-a-box collision non-Öpik system) and showed that the model Icarus, 48, 39-48. [4] Greenberg R. (1982) model. predicted the outcome correctly. Astron. J., 87, 184-195. [5] Namiki N. and To validate and verify the Cube model, Based on all the comparison results, we Binzel R.P. (1991) Geophys. Res. Letters, 18, we have applied it to various systems and conclude that the Cube approach provides a 1155-1158. [6] Bottke W.F. and Greenberg compared its predictions with previously good statistical estimate of the long-term col- R. (1993) Geophys. Res. Letters, 20, 879- published collision probabilities between as- lision probabilities among orbiting objects. 881. [7] Kessler D.J. and Cour-Palais B.G. teroids and comets, between Jovian satellites, When applied to an Öpik system – a system (1978) JGR, 83, 2637-2646. [8] Liou J.-C. et and among LEO debris – assuming all sys- where all objects have fixed (a, e, i)’s and al. (2003) LPSC XXXIV, 1828. tems obey the two Öpik’s assumptions. Over- randomly distributed (Ω, ω, λ)’s, this NASA’s Sodium Potassium Generation and Propagation Model P. KRISKO mechanism of core ejection and total NaK population, displays the orbital decay of Sodium potassium (NaK), used as the mass available for release. Even so, models droplets over time, and leads to a cursory coolant for the nuclear reactors of the former have been developed to account for the popu- observation of the sublimation rate of drop- Soviet RORSAT (Radar Ocean Reconnais- lation (i.e., ESA’s MASTER model and lets (no noticeable sublimation over the 8 sance Satellite) spacecraft, is believed to NASA’s EVOLVE NAKDEP subroutine). year time period). have been accidentally released during nu- NASA has recently developed its next The Haystack NaK selection require- clear core ejection events of many of the later generation NaK simulation model, ments were derived by J. L. Foster. They in- RORSATs. Objects identified as NaK drop- NaKModule. This model is designed for clude objects by radar polarization (> 0.92), lets have been observed over the last decade compatibility with the NASA 3-D debris en- Doppler inclination (> 62o and < 68o), and by several NASA radars (i.e., Haystack, vironment simulation model LEGEND. It altitude (< 1200 km). The total inferred popu- HAX, Goldstone) and through impacted ma- makes use of two main advances in recent lation as of January 1, 2003 consists of about terial recovery (LDEF). This population years, the NASA orbital propagator PROP3D 110,000 droplets ranging in size from 5 mm represents an orbital debris hazard to space- and the newly processed and fitted Haystack to 5.6 cm with a total mass of about 165 kg craft in low Earth orbit. Modeling efforts radar data from 1994 through 2002. Though +15 kg. Foster developed a linear regressive have been hampered in the past by lack of Haystack data has been used in the past for fit to the radar-cross-section data. This fitted data and lack of knowledge as to the precise NaK identification and modeling, the routine function is applied to droplet diameter and processing of that modified for use in NaKModule to account data assigns diame- for previously decayed droplets. ters based on the Though specific information on the NASA Size Estima- RORSAT reactor design and ejection method tion Model (SEM). is still wanting, the NaK ejection process is The current effort modeled in NaKModule by analogy with the makes full allow- reactor core ejection. Of 29 RORSAT upper ance of the fact that stages boosted into collection orbits and NaK droplets are listed in the US Satellite Catalog, 16 have spheres, and recasts performed a reactor core ejection after that the data droplets as end-of-life maneuver. It is believed that these spherical conduc- 16 ejection events resulted in a concurrent tors. This results in release of NaK reactor coolant. By back- reliable identifica- tracking the first ejected core 2-Line Element tion and size assign- set (TLE) to the most recent TLE of the re- 06 ment. The wealth of orbited RORSAT upper stage for all 16 NaK data over 8 events it is possible to estimate the core ejec- Figure 1. Cumulative number distribution with respect to diameter for years also increases tion direction and relative velocity. The cores the 75E Haystack dataset 2002 and the NaK model (NaKModule) at the statistical accuracy end of 2002. of the calculated Continued on page 7

6 www.orbitaldebris.jsc.nasa.gov NASA’s Sodium Potassium Generation and Propagation Model Continued from page 6 116,151. The num- appear to be ejected in the upper stage ram ber of identified direction at relative velocities ranging from NaK droplets in the about 6 m/s to 13 m/s. Since the observed Haystack dataset is NaK droplets do not appear to have been de- 417 for the year posited with a significant ∆v, this ejection 2002. This is a criterion is applied to the droplets as well. It function of the radar must be noted that the above result is in gen- beam geometry and eral agreement with that of previous models latitude, the altitude (i.e., MASTER and NAKDEP). of the detections, NaKModule generates individual drop- and the sensitivity lets at the time of each of the 16 RORSAT of the radar. The re-orbits. Each event is unique in diameter estimated true popu- distribution, initial ∆v distribution, and initial lation of the NaK orbital elements. Diameters and ∆v’s of each droplets based on droplet are randomly selected within con- the 417 Haystack straints noted in the previous paragraphs. detections is about Since about 110,000 droplets are calculated 115,800 for diame- ters down to 5 mm. to exist in orbit presently, the droplets in the Figure 2. NaKModule vs. 75E Haystack data at end of 2002 shows the code are generated one at a time (i.e., no Second, as noted atmospheric decay of NaK droplets over time. The smallest droplets grouping is needed or used for the smaller above, Haystack (those with the largest A/m values) decay fastest. droplets). Orbital and physical parameters of data diameter values each droplet are saved in arrays, which serve are routinely processed with the NASA SEM. ciency. This has been demonstrated by com- as inputs to the orbital propagator. All objects The NaKModule diameters are derived from parisons between the Haystack datasets and are propagated from time of generation to the the Foster fit, which is based on the spherical the ORDEM2000 populations. So it has been chosen time of completion. The output of the conductor theory. Generally speaking, then decided to restrict NaKModule to diameters model, the physical and orbital characteristics the Haystack data diameters are misidentified larger than 5 mm for the time being. Exten- of each droplet at a given time, represents a using the SEM. Finally, the smallest diame- sion of NaKModule to smaller sizes will be population that can be input to the NASA ters in the Haystack data (~3 mm) are not investigated in the future. model, LEGEND. matched in the model which has a deliberate The comparative populations are listed The area-to-mass ratio of each modeled diameter floor of 5 mm. The population at below. Differences between the two Hay- droplet is simply calculated, A/m = πr2/ NaK altitudes that is smaller than 5 mm in stack columns are due to statistical variation ρ(4πr3/3), where the density of the eutectic diameter is generally incomplete by reason of in viewing opportunities. NaK alloy (Na – 22 wt.%, K- 78 wt.%) is, ρ a Haystack radar ‘roll off’ in detection effi- = 0.9 gm/cm3. The natural decay of droplets leads to a modeled population that closely Parameter Haystack Data Fit Haystack Data Fit NaK Model (1994-2002) (2002) matches that of the Haystack dataset at the end of 2002 (Figure 1). Total Number of NaK The model and data diameter vs. altitude Droplets in Orbit 110,000 115,785 116,151 at the end of 2002 are shown in Figure 2. Total Mass [kg] of Several important points must be made about NaK Droplets in Orbit 165 ± 15 158 ± ~15 164 this figure. First, the model points number the total predicted in-orbit population of Table 1. Comparative values at the end of 2002. Growth in the Number of SSN Tracked Orbital Objects G. STANSBERY the AN/FPS-108 Cobra Dane radar located debris (see ODQN Vol. 4, Iss. 4). These tests The number of objects in Earth orbit on Shemya Island, AK (Figure 1). Cobra confirmed that the radar was capable of de- tracked by the US Space Surveillance Net- Dane is an L-band (23 cm wavelength) tecting and maintaining orbits on objects as work (SSN) has experienced unprecedented phased array radar which first became opera- small as 5 cm diameter. Subsequently, Cobra growth since the first of last year. On Janu- tional in 1977. The radar generates approxi- Dane was reconnected to the SSN and re- ary 1, 2003, the SSN was routinely tracking mately 15.4 MW of peak RF power (0.92 sumed full power/full time space surveillance ~10,870 objects in Earth orbit – ~8,860 in the MW average) from 96 Traveling Wave Tube operations on March 4, 2003. regular “catalog” and ~2,020 analyst satel- (TWT) amplifiers arranged in 12 groups of 8. The drop in the number of tracked ob- lites. The number peaked in mid September This power is radiated through 15,360 active jects from September to November does not with ~13,690 total objects (~9,030 catalog array elements. Cobra Dane was a correspond necessarily to a drop in the envi- and ~4,650 analyst) and as of November 21, “Collateral Sensor” in the SSN until 1994 ronment. More likely it is due to more Cobra 2003 stood at ~13,120 total objects (~9,100 when its communication link with the Space Dane resources (time and transmit power) catalog and ~4,020 analyst). Control Center (SCC) was closed. NASA being used to maintain orbits of objects as This growth is primarily due to the re- and the Air Force conducted tests in 1999 sumption of full power/full time operation of using Cobra Dane to detect and track small Continued on page 8 7 The Orbital Debris Quarterly News Growth in the Number of SSN Tracked Orbital Objects Continued from page 7 two catalogs is an increase in the population on about 100 of these objects. opposed to searching for new objects. Of the near 65° at mean altitudes near 9000 km. A The location (52.7 N, 174.1 E) and ori- ~2000 objects added to the analyst satellite Gabbard diagram (Figure 2) of these objects entation of Cobra Dane preclude it from de- list, about 1300 have been tracked by other shows perigees near 300-500 km altitude tection of low inclination orbits. Its sensitiv- sensors in addition to Cobra Dane. The re- with apogees in the 15,000-20,000 km range. ity and large collection area, however, have maining 700 objects are only being tracked A number of known breakups of Proton- allowed it to quickly add 2000 objects to the by Cobra Dane, according to Taft DeVere of Block DM Ullage motors have occurred with low Earth orbit tracked debris population. the Air Force Space Command Space Analy- these orbital parameters. However, very few sis Center. objects were cataloged from these breakups. One area noted in examination of the Cobra Dane is currently maintaining orbits

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0 250 300 350 400 Period (min) Figure 1. AN/FPS-108 Cobra Dane L-band Figure 2. Gabbard diagram of “analyst” satellites with orbital inclinations between 60° - 70° and phased array radar. with mean altitudes between 8,000 – 11,000 km. Results from the GEO Debris Survey with MODEST P. SEITZER, K. JORGENSEN, J. AFRI- serving is sent to the NASA Orbital Debris to a 20 cm diameter sphere) is due to system CANO, T. PARR-THUMM, M. MATNEY, Program Office at the Johnson Space Center limitations, and does not reflect the true de- K. JARVIS, & G. STANSBERY in Houston, Texas along with positions, an- bris population. In fact, the debris population Since early 2001, the University of gular motions and brightness estimates for all could be increasing to fainter magnitudes! Michigan's 0.6/0.9-m Curtis Schmidt tele- objects detected. What is most interesting is the analysis scope at Cerro Tololo Inter-American Obser- In this article we will highlight some of the observed motions of these 510 objects. vatory, Chile, has been used in a continuing results from the MODEST survey. There is a remarkable difference in the mo- optical survey of space debris at geosynchro- Figure 1 shows the magnitude distribu- tions of the bright versus faint debris. Figure nous orbit (GEO). This project is called tion of a sub-sample of objects detected in 4 2 shows the observed angular motions of MODEST, for Michigan Orbital DEbris observing runs starting in November 2002 these objects in the East-West (hour angle) Survey Telescope. The goal is to study the and ending in April 2003. We only include and North-South (declination) directions. A distribution of space debris in the geosyn- 510 objects which are not station-keeping in true station-keeping satellite which is con- chronous region. both East-West and North-South directions trolled would be at the center of these plots From its location in the foothills of the near the station-keeping ring. This excludes (0,0). Chilean Andes, the telescope can cover most most active satellites, and only includes ob- The bright objects show a very corre- of the orbital slots over the continental US. jects which are uncontrolled near GEO. This lated motion, which is to be expected if most Each night of observing, the telescope uses a is a dynamical definition of orbital debris at of them are on near-circular orbits at the scanning CCD to cover a strip of sky 1.3 GEO. same geocentric orbital radius. If everything degrees high by over 100 degrees long. A The figure shows a bimodal distribution was precisely at GEO in circular orbits, but GEO object can be detected up to a maxi- of debris. Bright debris at the left side is with different orbital inclinations, then the mum of 8 times as it drifts across the tele- mostly intact spacecraft and rocket bodies. plot would be a straight line at 0 arc-seconds/ scope field of view. A typical 14 night ob- Faint debris on the right side of the histogram sec in HA. But the observed curvature re- serving run covers over 1400 square degrees is too faint to be in the existing catalogs of sults from the drift velocity of uncontrolled of sky, centered on the station-keeping ring space objects, and the physical characteristics orbits, due to perturbations from the Earth’s of active satellites. Each morning a summary of this faint population is unknown. The of the results from the previous night’s ob- cutoff at R = 18th magnitude (corresponding Continued on page 9 8 www.orbitaldebris.jsc.nasa.gov Results from the GEO Debris Survey with MODEST Continued from page 8 bulge, and the Sun and Moon. It is expected that this correlated motion translates into the well known relationship between RAAN (Right Ascension of the Ascending Node) and orbital inclination for GEO objects. Faint objects show no such correlation. Physical explanations include eccentric orbits at GEO or circular orbits at a range of geo- centric orbital distances, or a combination of these. The current observations (taken over a 5.2 minute time span) do not have enough information to do a full orbital solution to resolve the uncertainty. Follow-up observa- tions over a longer time span are essential to solve this problem. Where did all this debris come from? There are only a few explosive fragmenta- Figure 1. The brightness histogram of 510 uncontrolled objects observed from November 2002 tions known at GEO. In an effort to monitor through April 2003. Bright objects are on the left, faint on the right. The cutoff at R = 18th mag- one source of GEO debris, we regularly nitude reflects system limitations, and not a limit to the true population of debris. (once per month) observe the station-keeping ring of active satellites. The goal is to look for pieces which have very recently fallen off active satellites and thus are moving very slowly. Figure 3 shows the brightness histogram for all observed objects within +/- 0.5 de- grees of geocentric orbital latitude = 0 de- grees, and with a total angular motion less than 0.1 arc-seconds/sec. This angular mo- tion cutoff is imposed to exclude faster mov- ing objects which are in the field of view of the system but which are on inclined orbits (and hence older). This figure shows only bright objects which are intact, operating spacecraft. The cutoff at the bright end is due to the fact that many operating satellites are too bright for the system to observe, and they saturate the detector. Figure 2. The observed angular motions of the 510 uncontrolled objects in Figure 1. Note the We see no population of faint, slowly very different distributions for bright versus faint debris. moving debris, which could have been re- cently released at zero velocity from larger spacecraft. Such debris might be solar pan- els, covers, insulation blankets, etc. We conclude that at least during this time span there was no significant source of debris in the station-keeping ring. MODEST observations will continue into 2004. Improvements under way should result in being able to reach R = 19th magni- tude, one magnitude fainter than the above results. We will continue to survey the GEO regime in an effort to determine the total population of objects at GEO above our sensitivity limits, and to regularly monitor for releases of debris. The orbital debris program at the De- partment of Astronomy, University of Michi- Figure 3. Brightness distribution of objects at or close to the station-keeping ring, and with a gan, is supported through grants from total angular motion less than 0.1 arc-seconds/second. Only bright objects are seen, nothing NASA’s Orbital Debris Program Office at fainter than R = 13. These are all intact, operating spacecraft. Compare this with Figure 1, the Johnson Space Center, Houston, Texas. which shows a large population of debris fainter than R = 14. 9 The Orbital Debris Quarterly News ABSTRACTS FROM THE NASA ORBITAL DEBRIS PROGRAM OFFICE 54th International Astronautical Congress 29 September—3 October 2003, Bremen, Germany Revisions to Nasa Policy Directive and Safety Standard for Orbital Debris Mitigation N. JOHNSON botic satellite missions, and this experience elements will remain largely unchanged, NASA Policy Directive (NPD) 8710.3, indicated that more explicit guidance to some guidelines will be improved, and the NASA Policy for Limiting Orbital Debris NASA enterprises and centers was necessary document will be more consistent with the U. Generation, was revised as NPD 8710.3A in to ensure that orbital debris mitigation issues S. Government Orbital Debris Mitigation January 2003, reflecting the growing impor- were handled in an efficient and comprehen- Standard Practices and other national and tance of orbital debris mitigation and a need sive manner. Work is now underway to re- international guidelines. An important lesson to identify and to expand the responsibilities vise the 1995 NASA Safety Standard (NSS) in the management of orbital debris learned of various organizations within NASA. The 1740.14, Guidelines and Assessment Proce- by NASA during the past eight years is that agency has acquired considerable experience dures for Limiting Orbital Debris, to update an effective orbital debris mitigation program in assessing orbital debris potential for a the document and to correct deficiencies and requires a detailed, formal process which is large number of human space flight and ro- areas of ambiguity. Although the technical supported by all agency organizations. Space Traffic Management Concepts and Practices N. JOHNSON management and its objectives. In the sim- in near-Earth orbit against the potential bene- Concepts of space traffic management plest terms, space traffic management should fits of a new regulatory regime. Most space- have been discussed for many years with lit- promote physical and electromagnetic non- faring nations do not yet exert control over tle progress to date due both to the complex- interference among the multitude of opera- the selection of orbital parameters for new ity of the issue and to a perceived lack of ur- tional space systems. However, contrary to space systems within their own countries, gency. Although a renewed interest in the popular belief, air and ground traffic control much less in an international context. The subject has arisen in some corners of the concepts and techniques offer few analogies prospects for such intrusive space traffic aerospace community, the challenges of applicable to the space environment. The management in the foreseeable future are not space traffic management remain unchanged. value of a space traffic management system bright. Perhaps the greatest challenge is reaching a must weigh the historical and legally en- consensus on the definition of space traffic trenched concept of the freedom of operation Changes Seen In Three Years of Photometry for GEO Objects K. JARVIS, J. AFRICANO, range, eccentricity and, in some cases, known Boxes and cylinders present different light T. PARR-THUMM, M. MATNEY, dimensions at time of launch. Many objects curves and different dependence on solar & G. STANSBERY that are correlated with known SSN numbers declination. Average absolute magnitudes of The CCD Debris Telescope has col- are seen on multiple nights throughout 1998, cylinders are found to be about two magni- lected several years worth of data of GEO 1999, and 2000 data. More than seventy ob- tudes dimmer than those of boxes. A general objects. The database built from these obser- jects have sufficient data points to study ab- darkening with increasing age of satellite is vations include such information as absolute solute magnitude variations. Brightening of also seen. magnitude, solar declination, phase angle, objects is seen to relate to solar declination. NAK Droplet Source Modeling J. FOSTER, JR., P. KRISKO, M. MATNEY, from the RORSAT satellites. Observations This produces a size ambiguity for a given & G. STANSBERY of the droplets from 1990 through 2002 have radar cross-section because of diffraction As part of the NASA orbital debris mod- shown slow orbital decay. Data from the effects. Previous work, used the NASA or- eling effort, a quantitative model is devel- Lincoln Laboratory Haystack and HAX ra- bital debris size estimation model that is oped for the large population of spherical dars have been examined for the time period based upon radar measurements of randomly electrically conducting objects in 65° inclina- from 1994 to 2002. Electrically conducting shaped objects with the radar wavelength tion circular orbits at the disposal altitude of spheres produce a distinctive polarization comparable to the object size. Here, the size the Russian Radar Ocean Reconnaissance signature allowing their identification, with distribution is estimated using the radar cross Satellite (RORSAT) spacecraft. These are high probability, among the other objects section of a conducting sphere, permitting an believed to be droplets of liquid sodium- detected by the radars. The droplets are com- accurate population size distribution determi- potassium (NaK) reactor coolant released parable in diameter to the radar wavelengths. nation. Upgrades to Object Reentry Survival Analysis Tool (ORSAT) for Spacecraft and Launch Vehicle Upper Stage Applications J. DOBARCO-OTERO, R. SMITH, cles is necessary to determine the risk to hu- The objectives of this study are to present J. MARICHALAR, J. OPIELA, mans upon ground impact. NASA Johnson updates and applications from the latest ver- W. ROCHELLE, & N. JOHNSON Space Center has been developing a com- sion of this code, Object Reentry Survival Prediction of reentry survivability of puter program that will predict survivability Analysis Tool (ORSAT) 5.8. Recent up- spacecraft and upper stages of launch vehi- of objects reentering the Earth’s atmosphere. Continued on page 11 10 www.orbitaldebris.jsc.nasa.gov

Upgrades to Object Reentry Survival Analysis Tool (ORSAT) Continued from page 10 of these new features include the ability to heating, and survival risk calculations out to dates to ORSAT include addition of para- input a range of values for a specific pa- the year 2050. This paper will present re- metric features, heat conduction through rameter, more accurate predictions for flat cent predictions of reentry survivability to boxes and flat plates, radiation to internal plate and box-shaped objects, higher initial sample spacecraft and launch vehicle upper components, improved material database, temperatures for internal components, im- stages using these updated features of OR- drag coefficients at low speeds, higher- proved velocity and kinetic energy predic- SAT. fidelity aeroheating algorithm, and improve- tions at impact, emissivity variations with ment of global population database. Results wall temperature, real gas effects on aero- Comparison of Photometric and Spectral Data from NASA’S CCD Debris Telescope (CDT) and the NASA AMOS Spectral Study (NASS) Observations K. JORGENSEN, K. JARVIS, comparing the changing magnitudes of the similar size and three box satellites with K. HAMADA, T. PARR-THUMM, overlapping CDT and NASS data, one can varying solar panel lengths are examined and J. AFRICANO, & G. STANSBERY explain aspects of the spectral signature in- the results are discussed herein. In addition A comparison study was conducted be- cluding orientation of the object, location of to the spectral signature, NASS converts the tween the CCD Debris Telescope (CDT) and the main body and solar panels, and possibly spectrum into photometric data, which can be NASA AMOS Spectral Study (NASS) obser- anomalies seen in the spectra. Initial investi- compared directly to the CDT data in an ef- vations. Photometric data was collected us- gation shows that the shape of the satellite fort to validate the NASS measurements. ing the CDT during the 1998-2000 observing (with and without solar panels) plays a large The same set of satellites observed spectrally sessions on various GEO satellites. From role in the magnitudes of the object. Also, will be discussed. 2001-2003, spectral observations were col- the spectral signatures show a change in loca- lected during NASS; several of these same tion of features dependent upon shape. For objects had been observed with the CDT. By this analysis, three cylindrical objects of NASA Long-Term Orbital Debris Modeling Comparison: LEGEND and EVOLVE P. KRISKO & J. -C. LIOU the one-dimensional LEO-only EVOLVE in scenario leads to a collisionally dominated This paper presents examples of the 2004. The β version of LEGEND is com- environment in LEO, as has been reported in long-term low Earth orbit (LEO) orbital de- pleted and is undergoing an extensive valida- past studies with EVOLVE. But with the ad- bris environments generated by the NASA tion and verification process. The historical ditional capabilities that LEGEND provides, simulation models LEGEND and EVOLVE. and projection test environments compared more details of the environments are now LEGEND (LEO-to-GEO Environment De- for this paper are part of this process. They available, such as the dominance of the LEO- bris model) is a three-dimensional debris show a great deal of similarity in the 10-cm LEO collision pairs, and the inclination clus- evolutionary model that is slated to replace and larger populations. The business-as-usual tering of collision pairs. Toward A Comprehensive GEO Debris Measurement Strategy M. MATNEY countries are now systematically making paper will outline the broad questions that In recent years there has been increasing observations of this region specifically to GEO observations should be designed to interest in the effects of orbital debris on the understand the debris population. We are answer. I will discuss how observations so Geosynchronous Earth Orbit (GEO) environ- now at a stage where we can begin to answer far have begun to answer those questions and ment. This region has great economic impor- specific questions about orbital debris in where they need to concentrate in the future. tance that is only expected to grow stronger these orbits, but what are these questions? This will include discussions of the benefits in the foreseeable future. The lifetime of any Are we asking the right questions? Are the and limitations of the statistical sampling debris created is very long, so that there is no observations we are pursuing answering the methodology versus the cataloguing method- effective sink to remove the debris in a most important questions? Are there changes ology. I hope to provide a framework for timely manner. Considerable resources have needed in the observation techniques to better future observations that will be of benefit to been brought to bear to understand the address the most important issues? Are there all GEO users. current debris environment at GEO. A changes needed in the types of instruments to number of optical telescopes in different answer the most important questions? This Improvements to NASA’s Estimation of Ground Casualties from Reentering Space Objects J. OPIELA & M. MATNEY The new predicted global population is based the debris shape. The new method uses a Recent improvements to NASA’s long- on a fixed distribution and variable total simple procedure based on numerical calcu- term estimation of ground casualties from population for each country or area. All ar- lations to include the geometry of the debris reentering space debris include refinements eas are then combined into the total global shape intersecting the human body. We use to the human population distribution and to population as a function of latitude. This the perimeter of the debris area to arrive at a the risk probability calculation. The previous creates a more accurate population estimation more accurate representation of the risk. human population distribution was based on based on non-uniform growth at the country/ These results have been tested for accuracy a global total, with a simple scaling factor for area level. The previous risk probability cal- against Monte Carlo models that simulate future years. This constrained the world’s culations were based on simplifying assump- how different shapes of debris could hit a population to change at the same fixed rate. tions for debris that did not take into account person on the ground.

11 The Orbital Debris Quarterly News Satellite Operations and Safety Workshop 22-23 October 2003, Westford, Massachusetts, USA Fundamentals of Debris Collision Avoidance J. FOSTER, JR. & G. STANSBERY debris collision avoidance maneuvering is The use of two line element sets for debris The statistical risk of a collision between required for a safe and effective process. avoidance is also discussed. a spacecraft and tracked (i.e. cataloged) space A formalism for quantifying risk and Before adapting any debris collision debris is generally small for a given conjunc- residual risk based on a maneuvering strategy avoidance strategy for any vehicle, the asso- tion. However, even this small risk may be and position and position uncertainty for the ciated risk and residual risk should be deter- unacceptable for a variety of reasons. In par- tracked conjuncting population is developed. mined. A debris avoidance process based on ticular the integrated risk over time may not Position and position uncertainty predictions collision probability offers the possibility of be so small. Collision avoidance maneuver- of the conjunction population need to be suf- identifying the infrequent high collision ing is one method of mitigating the risk and ficiently accurate so that the cost of maneu- probability conjunctions for which action can be quite economically effective for some vering a spacecraft is at least comparable to should be taken if at all possible. Such a vehicles. However, maneuvering also has the value of the mitigated risk. A process process has been adopted for both the Inter- associated costs and risks and should not be based on an exclusion volume is compared national Space Station and for the Space used in all cases. An holistic approach to with a process based on collision probability. Shuttle. AMOS Technical Conference 8-12 September 2003, Wailea, Maui, Hawaii, USA Obtaining Material Type of Orbiting Objects through Reflectance Spectroscopy Measurements K. JORGENSEN, J. OKADA, D. HALL, observed large orbiting objects spectrally and implications towards the determination of L. BRADFORD, J. AFRICANO, K. compared the overall shape of the reflectance material type of orbiting objects, spectro- HAMADA, G. STANSBERY, & P. spectra as well as the location of spectral ab- scopic Space Object Identification (SOI), and KERVIN sorption features in an effort to distinguish effects of space weathering. In addition to A collaborative effort between the Air material types. The Spica spectrometer, a the material type identification, an overall Force Maui Optical and Supercomputing sensor based on the commercial Acton Sp- increase in reflectance has been noted in vir- (AMOS) site and NASA Johnson Space Cen- 500 spectrograph, which is mounted on the tually all measurements of the orbiting object ter (JSC) began in September 2001 to study rear-blanchard of the AMOS 1.6 meter tele- and it has been found not to be dependent on the material type of orbiting objects using the scope, was the main instrument used in the altitude. Investigations of material type de- AMOS telescopes. This project, termed study. In this paper, we will discuss the re- pendence on this increase have been explored NASS for the NASA AMOS Spectral Study, sults of recent analysis of Spica data and its and the results will be discussed. Recent Results from NASA’s GEO Debris Optical Surveys M. MATNEY, G. STANSBERY, P. system. However, by using telescopes in a meter (1.3ox1.3o field of view) Curtis SEITZER, K. JORGENSEN, T. THUMM, staring mode to survey the environment, it Schmidt telescope in Chile. By removing K. JARVIS, & J. AFRICANO has proven very difficult to obtain orbital observation biases due to the observing For several years, we have been elements accurate enough to track an object geometry (i.e., where the telescope is pointed observing the geosynchronous orbit (GEO) and maintain an element set. Instead, for each frame), we show how the environment using optical telescopes for NASA’s goals have centered on populations of debris objects are distributed NASA’s Orbital Debris program. The goal characterizing the statistical distributions of in orbit distributions and in size. From this has been to try to understand the population objects in GEO and near-GEO orbits. In this information, it is possible to make general of debris objects too small to be easily study, we introduce calculations made with conclusions about the sources of debris in the tracked by the US Space Surveillance data from the University of Michigan 0.6/0.9 GEO environment. Meter-Class Autonomous Telescope for Space Debris Research G. STANSBERY, D. O’CONNELL, D. system, designated the Meter-Class search. Kwajalein Atoll was chosen as the NISHIMOTO, J. AFRICANO, & P. Autonomous Telescope (MCAT), will be location for MCAT because: 1) its low KERVIN deployed as part of the High Accuracy latitude location necessary for sampling low The National Aeronautics and Space Network Orbit Determination System inclination orbits, 2) its location allows it to Administration (NASA) and the Air Force (HANDS) and will use the Oceanit, Inc. K- measure a part of the GEO belt not covered Research Laboratory (AFRL) Maui Optical Star design. The telescope will operate in by other optical sensors, 3) it has a and Supercomputing (AMOS) Site are two different modes. During twilight hours it technically skilled workforce which can act cooperating to place a wide field of view, will sample low inclination orbits in a “track in a caretaker capacity. meter aperture telescope on Kwajalein Atoll before detect” mode. In the middle of the for space debris research. The telescope night it will perform a more standard GEO www.orbitaldebris.jsc.nasa.gov

12 www.orbitaldebris.jsc.nasa.gov MEETING REPORTS 2003 AMOS Technical Conference 8-12 September 2003, Wailea, Maui, Hawaii, USA The AMOS Technical Conference was recent results from NASA’s GEO debris opti- working. The final talk of the session was held at the Marriott Outrigger Wailea Resort cal surveys, specifically the MODEST data. given by the ESA’s Walter Flury which de- in Wailea, Maui from 8 to 12 September, Following his talk, Thomas Schildknecht of tailed the activities of Europe in the area of 2003. Over 400 representatives from high- the University of Berne gave a presentation space debris research. tech industry, academia, and government at- on the search for small-size debris in GEO tended the five day technical conference and GTO optically. Gene Stansbery (NASA/ Sessions included: Lasers, Adaptive Op- JSC) presented a talk about meter-class tics, High Performance Supercomputing, As- autonomous telescope currently in develop- MITIGATION tronomy, Space Weather, Metrics, Orbital ment. Mark Ackermann from Sandia Na- Debris, and Space Object Identification. tional Laboratories spoke about a blind Within the orbital debris session, seven search for micro satellites in LEO, more spe- COLUMN papers were presented with speakers from cifically the optical signatures and search International Progress around the world. Michael Oswald strategies. The next talk was given by Chris- in Orbital Debris (Aerospace Systems, ILR) spoke on the Ger- tian Tournes of Davidson Technologies man space debris observation in GEO. Next, which was about the prediction of orbital de- Mitigation NASA/JSC’s Mark Matney discussed the bris and the hazard assessments his group is In October 2002 after a multi-year effort, the 11 members of the Inter-Agency Satellite Operations and Safety Workshop Space Debris Coordination Committee 22-23 October 2003, Westford, Massachusetts, USA (IADC) adopted by consensus the IADC The second annual workshop, address- sented, in detail, the issues involved. It was Space Debris Mitigation Guidelines. These ing Satellite Operations, Space Weather, claimed that all recent debris avoidance ma- guidelines, which are similar to those in the Close Encounter Analysis, Collision Avoid- neuvers have been combined with scheduled U.S. and other spacefaring nations, repre- ance Techniques, Spacecraft Innovations, orbit maintenance maneuvers. Drs. Carl sent the first comprehensive and interna- Orbit Determination, and Space Measure- Toews / Eric Phelps (MIT/LL) presented a tionally accepted guidance for preventing ments took place at the MIT Lincoln Labo- statistical analysis of close approach dis- the unnecessary creation of orbital debris ratory (MIT/LL) Haystack Observatory in tances at geosynchronous orbit. Dr. J. Lee and for limiting its presence in Earth orbit. Westford, Massachusetts. Foster (GB Tech, Inc.) / Gene Stansbery The four major areas covered by the October 22nd: Heather Schidge of the U. (NASA/JSC) discussed the analysis leading guidelines are limiting debris released S. State Department spoke on Space Law li- to the current International Space Station and during normal operations, minimizing the ability related to orbital debris. Steve Hunt Space Shuttle debris avoidance procedures potential for on-orbit breakups, postmission (MIT/LL) spoke on use of radar measure- and stressed the need for careful analysis to disposal of spacecraft and orbital stages, ments of meteor trails to determine their ve- determine the operational cost and effective- and prevention of on-orbit collisions. locity distribution. Bill Bouchas (MIT/LL) ness of any debris avoidance process before In February 2003 the IADC formally presented the evolution of the Millstone Hill it is implemented. AF Lt. Brian Poller , 3rd presented the space debris mitigation Radar from inception to present. Frank Space Operation Squadron, Shriver AFB, guidelines to the Scientific and Technical Picher (MIT/LL) discussed the Kwajalein ra- proposed a debris collision avoidance proce- Subcommittee (STSC) of the United dar assets. Angel Borja (Satellites Mexica- dure. Richard Hujsak (Analytic Graphics) Nations’ Committee on the Peaceful Uses nas) presented a study on the feasibility of spoke on progress toward a Turn-Key Colli- of Outer Space (COPUOS) at the latter’s using solar radiation pressure on solar panels sion Avoidance Solution using TK Solver. In annual meeting in Vienna, Austria. At the to assist in re-orbiting satellites. the last open talk of the workshop, AF Lt. February 2004 meeting of the STSC, October 23rd: Dr. Rick Abbot (MIT/LL) Richard Lyon (MIT/LL) made an excellent discussion of the guidelines will resume reviewed the geostationary encounter data presentation on geosynchronous orbit estima- with the expectation that the guidelines will for the Commercial Resource Debris Avoid- tion with SSN observations and improved ra- be endorsed in whole or in part by the ance (CRDA) partner satellites and pre- diative force modeling. STSC and will then be forwarded to the full COPUOS for approval in June. Beginning in 2005, members of the MPLM STSC are encouraged to report on their Continued from page 3 for samples collected from the bumper perfo- ples were taken from around the perforation ration are shown in Figure 4. The central ob- efforts to implement the IADC space debris in the bumper to identify the source of the ject in the SEM image is the wooden probe mitigation guidelines. Meanwhile, the impact damage. that was used to collect impactor residue. International Standards Organization (ISO) An examination of the crater residue EDX analysis output revealed evidence of is drafting potential space debris mitigation samples was performed with the Scanning spacecraft paint. Currently, there are 26 im- standards, based primarily on the IADC Electron Microscope (SEM) & Energy Dis- pacts in the HVI database for the MPLM that space debris mitigation guidelines. persive X-ray (EDX) system at JSC Building is maintained at the Hypervelocity Impact The IADC space debris mitigation 31. The primary output product of this analy- Technology Facility at JSC. All impact data guidelines can be obtained via the NASA sis is the EDX spectra, which can be used to from the 5 MPLM missions compared well Orbital Debris Program Office website at match the signatures of known aerospace ma- with the BUMPER predictions. www.orbitaldebris.jsc.nasa.gov. terials. SEM output images and EDX spectra 13 The Orbital Debris Quarterly News INTERNATIONAL SPACE MISSIONS ORBITAL BOX SCORE (as of 31 DEC 2003, as catalogued by October—December 2003 US STRATEGIC COMMAND)

International Payloads Country/ Perigee Apogee Inclination Earth Other Country/ Payloads Rocket Total Designator Organization (KM) (KM) (DEG) Orbital Cataloged Organization Bodies Rocket Debris & Debris Bodies CHINA 38 283 321 2003-044A HORIZONS 1 USA 35734 35745 0.0 1 0 CIS 1351 2606 3957 2003-045A SHENZHOU 5 CHINA 332 336 42.4 1 4 ESA 34 305 339 2003-045G SZ-5 MODULE CHINA 340 356 42.4 INDIA 27 113 140 2003-046A IRS P6 INDIA 819 821 98.7 1 0 JAPAN 82 48 130 2003-047A SOYUZ TMA 3 RUSSIA 366 374 51.6 1 0 US 986 2795 3781 2003-048A DMSP 5D-3 F16 USA 842 854 98.9 0 4 OTHER 357 32 389 2003-049A CBERS 2 CHINA/BRAZIL 773 775 98.5 1 0 2003-049B CHUONG XIN 1 CHINA 731 751 98.5 TOTAL 2875 6182 9057 2003-050A SERVIS-1 JAPAN 984 1016 99.5 1 0 2003-051A FSW-3 1 CHINA 195 325 63.0 1 2 Technical Editor J.-C. Liou 2003-052A ZHONGXING 20 CHINA 35777 35797 0.2 1 0 2003-053A YAMAL 201 RUSSIA EN ROUTE TO GEO 2 3 Managing Editor 2003-053F YAMAL 202 RUSSIA EN ROUTE TO GEO Sara Portman 2003-054A USA 173 USA NO ELEMS. AVAILABLE 1 1 Correspondence concerning 2003-055A GRUZOMAKET RUSSIA 454 460 67.1 1 0 the ODQN can be sent to: 2003-056A COSMOS 2402 RUSSIA 19018 19314 65.1 1 1 Sara Portman 2003-056B COSMOS 2403 RUSSIA 18963 19102 65.1 NASA Johnson Space Center 2003-056C COSMOS 2404 RUSSIA 18961 19104 65.1 Orbital Debris Program Office 2003-057A UFO 11 (USA 174) USA 35781 35798 4.2 1 0 Mail Code C104 2003-058A NAVSTAR 53 USA 19963 20328 55.1 2 0 Houston, Texas 77058 2003-059A AMOS-2 ISRAEL EN ROUTE TO GEO 1 0 [email protected] 2003-060A EXPRESS AM-22 RUSSIA EN ROUTE TO GEO 1 1 2003-061A DOUBLE STAR 1 CHINA/ESA 550 78955 28.2 1 0 UPCOMING MEETING 18 - 25 July 2004: 35th Scientific Assembly COSPAR 2004, Paris, France. Space Debris Sessions are planned for the Assembly. These will address the following issues: advanced techniques to measure debris populations, latest modeling results, hyperveloc- ity impact tests, debris shielding, mitigation guidelines, and other related topics. More information on the conference can be found at: http://www.copernicus.org/COSPAR/COSPAR. html. HOW TO SUBSCRIBE... To receive email notification when the latest Orbital Debris Quarterly News is available, please fill out the ODQN Subscription Request Form located on the NASA Orbital Debris Program Office website. This form can be accessed by Visit www.orbitaldebris.jsc.nasa.gov to see the updated NASA Orbital Debris Program Office website. For more information on updates to the website, see the article Orbital clicking on “Quarterly News” in the Quick Debris Website Update on page 2 of this issue. Links area of the website.

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