The workshop was opened by the chair of the Committee for the Assessment of NASA’s Orbital Debris Programs, Donald Kessler, who welcomed the guests, provided a synopsis of the overall study underway and the objectives of the workshop, and described the panels that were formed prior to the workshop.
The panels presented at the workshop in the following order:
1. Panel on NASA Meteoroid and Orbital Debris Programs,
2. Panel on NASA Mission Operators,
3. Panel on the Role of NASA’s MMOD Programs and Their Relationship to Other Federal Agencies,
4. Panel on MMOD and the Commercial Industry Perspective, and
5. Panel on Orbital Debris Retrieval and Removal.
The leads for NASA’s meteoroid and orbital debris (MMOD) programs, as noted in the Preface, described their organizations, objectives, obstacles to achieving those objectives, and opportunities for advancing the state of the art. The MMOD programs provide a service function, which gives them the capability to go across missions, centers, and agencies in the areas of design assistance, pre-launch review/assessment, launch and on-orbit conjunction assessment, and pre-decommissioning/disposal assistance. The MMOD programs interface with other NASA divisions, U.S. agencies, commercial entities, and international organizations, but there does not appear to be a consolidated research budget for the programs, and NASA does not have the capability to remove existing debris from orbit.
Workshop participants described obstacles to designing spacecraft with reduced risk of damage from MMOD. While extensive research on MMOD effects, mitigation, and elimination has been underway for more than 30 years, and debris can be tracked reliably down to sizes of 10 cm and sometimes less, an issue that has been pervasive since the beginning of the program is that considerable damage to space objects can be caused by particles that are an order of magnitude smaller than 10 cm, which can be more numerous and difficult to eliminate from orbit (Figure 1). This obstacle to fully characterizing the environment sometimes puts NASA in a difficult situation, it was explained, because the agency currently has a gap between detection capabilities and risks inherent to operating in the space environment for many spacecraft systems.
FIGURE 1 Meteoroid and orbital debris detection platforms and capabilities. SOURCE: John Lyver, NASA, presentation at the Workshop to Identify Gaps and Possible Directions for NASA’s MMOD Programs, March 9, 2011.
Another obstacle facing NASA is that even for particles that are centimeters in size, the agency lacks a process for determining how particle shape plays a role in the damage that can be caused by an impact. Methods to incorporate particle shape into impact models have not been validated, and hence the application of a safety factor in spacecraft design techniques may result in uncertainty to both weight and physical dimensions of a spacecraft designed to operate in the MMOD environment.
A third obstacle cited by panelists as adding uncertainties in design is that experimental facilities for testing spacecraft damage, including via hypervelocity testing, generally employ spheres or simple shapes made from aluminum. Moreover, typical impact speeds at these test facilities do not exceed speeds of 7-8 km/s, whereas the average relative impact velocity of orbital debris particles in low Earth orbit (LEO) is around 9 km/s, and orbital debris and meteoroids can reach relative impact velocities of up to 15 km/s and 70 km/s, respectively.1 Although ultra-high-velocity testing facilities exist, they are more expensive than facilities with conventional high-velocity-testing techniques, and they employ particles on the average of several microns in size. Thus extrapolation from such experiments, which do not duplicate debris shape or material properties, introduces even more uncertainties due to a mismatch of collision velocity.
Panelists did point out that the space shuttle and some spacecraft parts returned from orbit, for example solar panels from the Hubble Space Telescope (HST), have exhibited debris damage that can be analyzed, although the conditions of impact (debris shape, size, and impact velocity) are seldom known with precision.
1 Eric Christiansen, “Hypervelocity Impact Technology (HVIT) Group,” presented at the NRC Workshop to Identify Gaps and Possible Directions for NASA’s MMOD Programs, March 9, 2011.
Research by NASA’s Orbital Debris Program Office (ODPO) has demonstrated that even if additional spacecraft are not placed in LEO and if the 25-year rule2 for the maximum lifetime of a satellite is reduced significantly and followed by all agencies, the amount of debris in orbit has already reached the point that a continued increase in debris is likely due to collisions between objects already in orbit, which produce increasing numbers of collision products as time passes. This reality has impressed on policymakers the need to carry out R&D on the retrieval/removal of objects, particularly large objects, from orbit, and attention to this subject is now increasing as a result of its inclusion in the 2010 National Space Policy. Apart from preparing for the future of orbital debris prevention and mitigation, NASA and the U.S. government already have tools to address this issue to some degree.
Panelists discussed the use of tools such as conjunction assessment risk analysis (CARA) to forecast possible collisions between cataloged objects and operational spacecraft. CARA takes information from the Department of Defense’s (DOD’s) Joint Space Operations Center (JSpOC) and converts it into collision probabilities, which are then sent to the appropriate mission directors, who are ultimately responsible for making decisions on whether to initiate an orbit change for a satellite in potential danger. It was stated that, although this tool works efficiently, it can only be as good as the information entered, since particles smaller than what JSpOC can track can still cause significant damage. A panelist suggested that improving the quality and detail of the data received for CARA was a goal that could be met in part by improvements in how JSpOC screens and cross-checks its ephemeris3 data before sending it to NASA, as well as by having NASA join the Space Data Association, a non-profit organization of commercial satellite operators established to provide this type of support to industry users.
In addition to tracking and collision analysis efforts, it was noted that greater attention is being given to designing spacecraft for “passivation”4 so that spacecraft are less likely to create more debris from explosions or if struck by an object. Space systems can also be designed and constructed so that they are less likely to survive to the ground when they enter the atmosphere, thus posing less risk to people on the ground.
Nevertheless, technology and engineering solutions are still subject to administrative pressures. Such issues were brought up by a number of the NASA speakers, but one administrative issue was repeatedly mentioned: budgets are presently set on a year-by-year basis instead of a 2-year basis as in the past. This makes planning very difficult. For example, it was stated that there will likely be cost-overruns on the Meter Class Autonomous Telescope, which may occur late in this fiscal year. This would present the project manager with a challenge: Should they save a reserve and risk losing it on October 1? Or should they spend it all now and risk running out too early? The funding cycle is absolute; after the fiscal year, any remaining funds from what were provided that year disappear.
Another issue brought forward by the NASA leads is that the workforce in this area is not extensive enough to ensure continuity of expertise, nor are there sufficient resources to train new people or hire young engineers. This, too, is essentially a budgetary problem.
Research in the area of meteoroids is prone to many of the same problems as elucidated above, a point emphasized by one speaker who mentioned that approximately 40 percent of MMOD impacts on the space shuttle’s surface are from meteoroids. The task for the Meteoroid Environment Office is to identify the “background” meteoroid environment and the occasional meteoroid showers and their
2 The “25-year rule” is a guideline adopted by the international organization, the Inter-Agency Space Debris Coordination Committee (IADC) in its “IADC Space Debris Mitigation Guidelines” released in 2002 and revised in 2007. The “rule” encourages entities with objects in low-Earth orbit to ensure that their spacecraft and/or launch hardware are in an orbit that will decay and cause said object to reenter Earth’s atmosphere within 25 years to mitigate the creation of more orbital debris. See http://www.iadc-online.org/Documents/Docu/IADC_Mitigation_Guidelines_Rev1_Sep07.pdf.
3 Data that provides the positions of spacecraft and other astronomical objects at a given time.
4 Passivation is the disabling of a satellite or object in space to prevent that object from creating more orbital debris, such as by exploding in orbit or colliding with another spacecraft. This can be accomplished in many ways, including draining onboard batteries, expending excess propellant, and/or positioning the object for atmospheric reentry.
characteristics and then provide forecasts of possibly damaging effects in the regions of space outside LEO, where orbital debris does not dominate the hazard.
The NASA speakers expressed the need for research to develop a model of meteoroids in the outer solar system (Jupiter and beyond), improve instrumentation calibration for measuring meteoroid properties and trajectories, and resolve the question of whether spacecraft instrument failures are due to inherent component degradation or to electrical effects caused by impact of meteoroids traveling at velocities up to 70 km/s. The latter subject raised a good deal of commentary, because, until recently, electrical failures were assumed to be caused by either internal effects or space weather and were simply labeled as anomalies. However, one of the panelists described working with hypervelocity and plasma physics experts to investigate electrical anomalies caused by high-velocity meteoroid strikes so as to provide data that will better inform people dealing with this issue.
Recent advances in low-mass and low-power sensors, it was explained, open the possibility of covering large areas of a spacecraft with MMOD impact detection and location systems, which could also provide data for anomalies and failure analysis and perhaps even alerts on debris streams. Moreover, calibrated sensors could provide data on the size and flux of MMOD particles, and multifunctional shielding (combining thermal, radiation, self-healing and MMOD protection functions) could reduce MMOD risk and shielding mass.
At the end of the session, attendees from non-NASA organizations praised the efforts and accomplishments of the NASA MMOD programs, particularly when taking into account the small budgets under which the various entities operate.
Five NASA project and mission managers described specific missions from an operations standpoint, emphasizing the design tools they use to meet MMOD requirements and their experiences with actual MMOD encounters or anomalous effects that may be attributed to such encounters. The missions represented on this panel were the Global Precipitation Measurement (GPM) mission; the ARTEMIS mission, which studies the Earth-Moon environment; the Hubble Space Telescope; the Earth observation missions Jason-1 and Ocean Surface Temperature Mission/Jason-2; and NASA Goddard Space Flight Center’s Space Science Mission Operations project, which is responsible for the management of space science missions from conceptual development through end of operations.
Committee members were interested in learning what MMOD-related problems missions encounter throughout the lifetime of a spacecraft, how NASA’s MMOD programs meet mission planners’ and operators’ needs, and what information mission managers are using to make decisions related to the operations of a spacecraft—in particular, those decisions related to MMOD.
The speakers said that Debris Assessment Software (DAS), which is a single modeling tool, is used for determining compliance with MMOD-related design requirements,5 but a number of speakers indicated that, although the software was easy to use and provided free to the public, it was essentially a “black box.” Users do not know how DAS arrives at its outcomes, so the user is unsure whether the results are conservative or not. The Object Reentry Survival Analysis Tool (ORSAT), which is used to predict the reentry survivability of satellite and launch vehicle upper-stage components that are entering due to orbital decay or from controlled entry, was stated to be more accurate than the reentry survivability predictor in DAS. Nevertheless, DAS was given a favorable opinion by panelists when used for its intended purpose.
5 All NASA missions are required to comply with the NASA Technical Standard 8719.14, “Process for Limiting Orbital Debris,” which provides “uniform engineering and technical requirements for processes, procedures, practices, and methods” for NASA projects and programs; available at http://www.hq.nasa.gov/office/codeq/doctree/871914.pdf.
In addition to demonstrating compliance with MMOD-related design requirements laid out in NASA Technical Standard 8719.14, the GPM program manager highlighted that the GPM mission used DAS to determine the shielding design for the satellite as well, which is not the software’s primary purpose. Some panelists expressed a desire for better verified software to assist with shielding design, and one speaker explained that the project team would have liked to have verified the design by using the BUMPER model but could not, primarily because of factors out of the project team’s control, namely funding.
Some of the speakers discussed the question of anomalous behavior and whether it could be traced to MMOD effects. Examples were given to illustrate the analysis that must be carried out to explain why a given effect that was initially noted as an instrument response might, for example, lead to conjecture that it could have been due to a meteoroid or orbital debris collision. When the Artemis spacecraft lost functionality of an instrument, the designers concluded that the support structure most likely broke due to fatigue, but the speaker highlighted the difficulty in arriving at a clear reason for the loss of data when first presented with a spacecraft anomaly.
The Hubble Space Telescope presented an interesting case because its development in the 1970-1980 time frame meant that it was not designed to perform any collision avoidance and was constructed with no significant shielding against MMOD impact strikes. As the risk of orbital debris damage increased, the HST team developed an orbit debris conjunction mitigation contingency procedure to handle predicted possible collisions with an object in the tracking catalog. The procedure uses a combination of real-time commanding and flight software macros for configuring HST in the event of a possible conjunction, and myriad contingency actions have been developed as a result. However, no conjunction assessment to date has caused an interruption to HST science operations. In case of a predicted close encounter with orbital debris, HST cannot change orbit but can only orient itself in such a way as to reduce the probability of a collision. The degree of risk involved in such a maneuver, however, needs to be weighed against the potential collision risk. To date, HST has never conducted this type of procedure. HST has furnished a great deal of photographic evidence of meteoroid collisions taken during space shuttle servicing missions, which have helped to build up a catalog of information useful to designers in the future.
The question was asked as to whether there has been any loss of science data or loss of engineering and vehicle performance on HST due to any type of debris. The reply was that most or all of the impacts on HST have been from meteoroids, not orbital debris, and they have not degraded or affected HST operations.
Two other missions represented at the workshop—Jason-1 and Jason-2—are collaborations between NASA, the National Oceanic and Atmospheric Administration (NOAA), and Centre National d’Etudes Spatiales, the French space agency, measuring sea levels, water vapor in the troposphere, and ocean surface temperature, among other scientific measurements. The international partnership necessitates the sharing between the two agencies of information that is protected both by International Traffic in Arms Regulations6 and a similar set of French export regulations. While the results of calculations on such matters as conjunction assessment numbers could be shared, the methods behind the calculations typically could not be shared, so no critical comparisons between the underlying assumptions in the calculations could be made.
The unintended consequences of compliance with debris regulations were illustrated in the case of the next satellite in this series, tentatively referred to as Jason-3 and/or Jason-CS, which is being designed to carry additional propellant that could be used to decommission or passivate the mission. However, carrying extra propellant would result in an increase in the collision cross section of the satellite, leading to a greater probability of collision and a greater debris risk if the propellant tank ruptures. If the mission fails and cannot be fully decommissioned, a drifting spacecraft with a much larger explosive potential would remain in orbit. Most spacecraft used for science missions, in particular those
6 International Traffic in Arms Regulations, available at http://www.pmddtc.state.gov/regulations_laws/itar_official.html.
designed and launched prior to implementation of NASA’s current engineering design standards for mitigating creation of orbital debris, typically do not maneuver during their lifetime and lack propulsion systems that would allow them to deorbit for atmospheric reentry or avoid a collision.
Representatives from the DOD, Federal Aviation Administration (FAA), NOAA, Department of State, and the Federal Communications Commission (FCC) involved in space policy, space and Earth science, and MMOD issues discussed challenges they face from the space environment, interagency issues and opportunities for collaboration, and how and to what extent they engage NASA’s MMOD programs.
One of the panelists noted that at the beginning of 2010, the Space Protection Program, a joint U.S. Air Force Space Command and National Reconnaissance Office program that advises the intelligence and military community on how to protect their critical space assets, conducted a study on orbital debris and concluded that orbital debris was a very significant problem requiring immediate action. The United States, the study concluded, could not wait to develop removal technologies, and an implementation plan was discussed. That plan was never implemented for the following reasons:
• Most of the proposals had a weapons-like character about them;
• No agreement could be reached on who would be responsible within the United States or internationally;
• The cost did not justify moving forward; and
• There was a lack of agreement on policy.
When it came to the point of including a statement in the text of the 2010 National Space Policy on actively removing debris from space, a panelist recalled, that phraseology was removed from the final version and the text now reads only that studies related to removal should be carried out.
One of the panelists made the observation that, in his opinion, if there is going to be any active debris removal in our lifetime, it will be done by commercial organizations. He cited an announcement that Intelsat is having informal talks with NASA about refueling satellites in geosynchronous or geostationary Earth orbit (GEO) for removal, and noted that ViviSat and DLR Germany are also working on this approach. He went on to say that U.S. policy for debris removal will not be developed, written, or changed in our lifetimes unless there is a catastrophic event in space. In the interim, NASA could fund commercial activities that would lead to debris removal, and it could also continue to fund research in this area.
A spokesman for the FAA said his agency is a regulatory agency, and its authority is more limited, in a sense, than NASA’s authority. The FAA has the authority to license launches and reentries that are purposeful and designed to survive substantially intact. The only MMOD-related requirement the FAA has is for passivation of upper stages by depleting propellants and drawing down energy sources. He said that his organization receives excellent support from NASA’s ODPO. The FCC is also a regulatory agency and derived the baseline for its guidelines for the mitigation of orbital debris from the Inter-Agency Space Debris Coordination Committee (IADC). However, the FCC representative did say that the FCC often sends people seeking commercial licenses from the FCC to NASA’s ODPO Web site to conduct their own preliminary assessment there before filing for a license. The FCC representative further bolstered NASA’s reputation in the MMOD community by saying that the FCC looks forward to NASA’s continued work, because “it’s where the FCC goes to.”
While NASA has a criterion of a 1 x 10-4 probability of risk for casualties on reentry, the FAA has a requirement of a 30 x 10-6 probability of ground damage from debris for just a launch, or for launch and controlled reentry combined, thereby underscoring differences in handling MMOD across agencies.
This is one of many differences that illustrates the varied MMOD governmental policies in place that are not always coordinated across agencies, a fact that did not go unnoticed at the workshop. The FAA does not follow the 25-year rule, because it has not done a cost-benefit analysis to support its implementation. In order for the FAA to justify new policies or regulations, the agency representative explained, any new policies or regulations would have to decrease the cost of a casualty 10-fold based on the FAA’s current reentry damage/casualty probability threshold. The FCC, on the other hand, does follow the 25-year rule end-of-life guideline, but the FCC representative also noted that the issue of debris mitigation is not at the forefront of the organization’s planning apparatus.
A representative of the State Department discussed international efforts to mitigate the effects of orbital debris. The most prominent international body for information exchange on space debris is the 11-nation IADC. Since 1993, the IADC has conducted annual meetings to discuss research results in the areas of measurements, modeling, protection, and mitigation. The IADC is internationally recognized as a space debris center of competence and influences space debris mitigation activities through the United Nations (UN) Committee on the Peaceful Uses of Outer Space–Scientific and Technical Subcommittee.
As the State Department looks over the horizon, it sees an increasing number of governmental and non-governmental actors operating in space. The State Department is compelled to ensure that all groups conduct themselves responsibly in space, but the optimal approach remains elusive for now. The State Department is looking at what are some minimal actions nations can take to mitigate the creation of orbital debris, as well as reduce the risk to space assets from natural and manmade debris already in orbit. International avenues for addressing MMOD issues are adequate up to a point, but international guidelines are non-binding, and there is no supranational adjudicative body tasked specifically with international space law. The prime challenge in the future will be translating international consensus and standards into action on the national stage for individual countries. Although the majority of the world’s nations are signatories to treaties like the UN Outer Space Treaty and UN Liability Convention, there remain some that have yet to sign. This problem is compounded by countries, including treaty signatories like Brazil and India, that acknowledge the need for a sustainable space environment but do not want their space programs impeded by guidelines developed by the nations that created the problem of space debris in the first place—namely Russia (and former Soviet Union) and the United States.
The panel speakers all asserted that they derive tremendous value from NASA’s ODPO, which also allows their agencies to speak knowledgeably about MMOD issues in international and interagency forums. In the case of NOAA, NASA builds the spacecraft and treats them as they would a NASA mission. Nonetheless, the relationships between these agencies and NASA’s MMOD programs vary from agency to agency, and it was revealed at the workshop that there were varying degrees of coordination on the matter within the agencies themselves. When asked who the technical lead is within DOD on MMOD issues, the DOD panelist said that there was no such position at DOD, an agency with an even larger space portfolio than all of the U.S. government’s civil space programs combined. When this question was asked for the entire U.S. government, the panelists said that there is no true lead for MMOD in the U.S. government as a whole either.
Responding to a question about data sharing and spacecraft anomaly analysis and cataloging, panelists explained how interagency data either are not shared or are heavily edited before going from classified to non-classified status, and that the commercial industry is not a particularly helpful or reliable source of anomaly information.
Representatives of the satellite communications firm Iridium Satellite Communications, aerospace manufacturer Lockheed Martin, and insurance firm XL Insurance talked about how MMOD affects business operations, from the manufacturing of spacecraft to making on-orbit decisions about possible collisions. Among many other topics, this panel discussed the tools industry uses to make
decisions affecting their space assets, what their relationship is with NASA’s MMOD programs, and what opportunities for collaboration there might be between industry and NASA.
After hearing from various NASA employees and other federal agency representatives, the panel provided a different perspective on the MMOD issue, starting with a description of the Iridium firm and the 2009 collision event between Iridium 33 and the Russian satellite Cosmos 2251. In the past, explained the Iridium representative, there was never any information on orbital characteristics that could be relied on for actionable decisions by program/mission managers, including two-line elements.7 Up until 2009, in fact, Iridium had never adjusted a satellite’s orbit, and the predominant attitude toward spacecraft and orbital slots was the “Big Sky”8 viewpoint. A review of predicted conjunctions for February 10, 2009, showed a possible collision between the Iridium 33 and Cosmos 2251 satellites, but that conflict was 16th on a list of possible conjunctions, so no action was taken.
The Iridium 33-Cosmos 2251 conjunction was the first payload-to-payload collision in the history of spaceflight. Following the collision, Iridium initiated an anomaly recovery process, coordinating with JSpOC throughout this process. As a result, the company has a more robust relationship with JSpOC, but the Iridium representative did not mention involvement from NASA’s ODPO. When asked if a more careful analysis of conjunction using all of the data available would have predicted the collision, the Iridium representative said that the company is in the midst of conducting an analysis, and a report will be published with those results.
Today, Iridium receives daily conjunction assessment updates from JSpOC, which are assessed to gauge the level of risk for each reported conjunction. Since the 2009 conjunction event, Iridium has made 41 maneuvers, whereas before 2009 it had made none.
Although Iridium has not interfaced a great deal with NASA or NASA’s ODPO, the representative from Lockheed Martin explained how that company incorporated NASA’s work in MMOD into the design and construction of NASA’s Orion crew vehicle capsule. Orion is the first human-rated reentry spacecraft designed to stringent MMOD-related design requirements for a variety of missions, including to LEO, the Moon, and Mars. Engineers make difficult decisions when designing spacecraft shields, since there are always tradeoffs to increasing shielding, such as increased cost, volume, and mass to the spacecraft (for mechanical, not electrical, shielding). The increase of orbital debris in the space environment only makes this task harder. The speaker identified two levels of concern in designing Orion: (1) loss of crew, which includes damage to the Orion vehicle either in orbit or during reentry, and (2) loss of mission, which includes damage that prompts a mission abort or an unsafe vehicle reentry. The project team used the BUMPER II code to analyze more than 500 shield configurations, which will allow Orion to stay in orbit for roughly 6 months. In addition, NASA’s Orbital Debris Environment Model (ORDEM) and Meteoroid Environment Model (MEM) were combined with Orion attitudes and trajectories for calculating a variety of design-related needs based on mission scenarios. Finally, the design team performed shield tests at facilities such as the University of Dayton Research Institute and White Sands Test Facility. These facilities can launch particles at between approximately 6.5 km/s and 10 km/s, but, as some committee members pointed out, these speeds are still below the maximum relative impact velocities for debris in LEO and lower by a factor of 2 to 10 than the speed of all meteoroid populations. The result of these tests and analyses is an MMOD shielding mass that is a little more than 0.5 percent of the total vehicle mass.
The representative of Lockheed Martin also discussed launch vehicles, saying that there are no requirements for launch vehicle de-orbiting of spent stages. However, in the case of a transfer orbit GEO, a launch company can decay the orbit of the spent stage so that atmospheric drag will eventually cause
7 A two-line element is a set of two 69-character lines of data used to describe the orbit and perturbations of a satellite around Earth. New two-line element sets are generated by the Air Force Space Command on an as-needed basis and not according to a previously established timetable.
8 According to “Big Sky” proponents, the number of spacecraft in Earth orbit is negligible, given the overall scale of the environment being considered.
reentry of the rocket. In addition, efforts are made to ensure that propellant tanks are emptied and depressurized after launch.
The potential for further debris creation, perhaps by a spent rocket stage that has not de-orbited yet, relates directly to another area covered by this panel: space insurance. The XL Insurance representative described the state of the space insurance industry as having events that are low in frequency but very high in severity. This issue is compounded by the fact that the space insurance industry does not have a very large funding reservoir. Space insurance covers first-party losses (e.g., loss of asset, loss of revenue) and third-party losses (e.g., liability for damage to third parties) of satellite operators, launch providers, satellite and launch vehicle manufacturers, and others. There are currently 195 insured satellites in orbit for a total insured value of $19.8 billion. Over the past decade, the probability of satellite failure after completion of orbit raising and initial testing, as assumed by the insurance industry, oscillated between 1.5 and 2.0 percent per year. The speaker also noted that MMOD damage is covered by typical space insurance packages.
Third-party insurance claims for objects in space can be complicated by the vagaries of international space law. Determining the cause of an incident and subsequent liability can be very difficult. According to the UN Liability Convention of 1972,9 the launching state is liable for objects in space that were launched from within its borders. Determining the cause of an incident and subsequent liability, however, can be very difficult. According to the UN Liability Convention of 1972, a launching state can be liable for its own launches or launches it procures that occur from its own territory or facilities. Fault is the standard that applies to damage that occurs in space. Determining fault requires proving that the launching state’s conduct violated an applicable standard of care. The treaty regime also makes it illegal for a nation to unilaterally remove an object or derelict spacecraft from orbit if it is not also the launching state. In the case of the Iridium-Cosmos collision, there was no clear onus of responsibility for maneuvering either satellite.
When panelists were asked to suggest areas in which NASA could provide augmented or additional services, one panelist expressed a desire for more and “better” data on the outer solar system environment and more high-velocity shield testing. Another panelist wanted more effort made to enhance the ability to track satellites in orbit, including greater cooperation between NASA and JSpOC. The idea of using hosted payload slots to launch missions to characterize the MMOD environment was brought forward as well. Finally, a panelist said that ODPO’s quarterly newsletter is very useful, but that he would like to see the charts used in the newsletter updated more frequently, as well as for NASA to provide greater access to more regularly updated data elsewhere. After hearing this comment, a NASA employee told the gentleman to get in touch with him, and he would provide the panelist with whatever information he needed.
The 2010 National Space Policy calls for NASA and DOD to lead research and development efforts in orbital debris retrieval and removal. Representatives of NASA’s technology development programs, DOD, and the Office of Science and Technology Policy (OSTP)10 talked about these efforts and what it would take to help engineer a safer space environment.
Space policies convey themes and opportunities to external organizations, as well as provide guidance to government agencies. There have been national space policies in the United States since the
9 Convention on International Liability for Damage Caused by Space Objects, available at http://www.oosa.unvienna.org/oosa/SpaceLaw/liability.html.
10 The Office of Science and Technology Policy, an executive branch-level office, is the lead office for providing the president of the United States with scientific and technical advice, as well as coordinating presidential science and technology policy throughout the U.S. government.
Eisenhower Administration, and, according to the OSTP representative, the UN Outer Space Treaty will continue to be a foundation for U.S. space policies.
The 2010 National Space Policy places significant new emphasis on broad international cooperation with the goal of increasing stability and transparency in space. Preserving and ensuring a sustainable space environment is necessarily an international endeavor, and there will only be more national and non-governmental actors in space over the coming years and decades.
The new space policy, explained the OSTP representative, tries to address orbital debris in multiple ways to strengthen measures to minimize creation of debris; call for agencies to continue to lead in the development and adoption of standards; improve data sharing, both among agencies and internationally; and encourage agencies to utilize tools already in their arsenal to mitigate and possibly remove orbital debris. Some examples include finding synergies between U.S. Strategic Command and NASA models, data collection, and conjunction analyses. Emphasis is placed on research and development because the government does not yet know what technologies will ultimately be necessary or are feasible on the scale required for effective orbital debris retrieval and removal, as well as guaranteed prevention of collisions if such an event is predicted. Although the National Space Policy calls for research and development in this field, it does not specify a threshold or goal, but rather intends such research and development as a beginning to the entire process.
The recently created NASA Office of the Chief Technologist (OCT) plans to work on new “game-changing” technologies across many disciplines, including orbital debris retrieval and removal. Among the new division’s many goals, OCT will be the principal NASA advisor and advocate on matters concerning agency-wide technology policy and programs, direct management of OCT Space Technology Programs, and coordination of technology investments across the agency. OCT will work on technologies from technology readiness levels (TRLs) 1-7, divided into three groups: early-stage innovation (TRL 1-2), game-changing technology (TRL 3-4), and crosscutting capability demonstration (TRL 5-7).
Regarding orbital debris, OCT will participate in studies of the problem and partner with others to develop technologies that allow for orbital debris hazard mitigation and removal, including releasing solicitations for orbital debris-related technologies that have specific parameters. NASA’s ODPO will be the focal point for these activities and, among its other responsibilities, will remain in charge of environment characterization, while OCT focuses on the development of new technologies. In formulating its solicitations, OCT is using responses from requests for information and is conducting discussions with mission directorates, the Orbital Debris Program Office, and industry.
The OCT representative also considered the idea of a U.S. government interagency study to address the issue of orbital debris. None of NASA’s mission directorates have taken responsibility for addressing orbital debris, even though the 2010 National Space Policy tasks NASA with taking a lead. When asked how such a study might proceed, panelists replied that there are a variety of ways a study could be convened. The process could begin in a number of ways, including in the executive branch, at the agency level, or in an informal setting between government employees.
Despite an acknowledgment from NASA and OSTP that MMOD is a major issue that needs to be addressed, an even more immediate concern voiced by a senior NASA official was the agency’s budget, echoing earlier statements made by the Session 1 panelists. Not only is the amount of funding available for the agency a source of anxiety, but so too is the uncertainty of that funding under a series of continuing resolutions instead of a true appropriations bill. One panelist said that he has not yet seen a credible amount of funding for implementation or research into characterizing or improving the space environment.
Nevertheless, NASA will continue to consider MMOD concerns for exploration technologies, and agency-level requirements to reduce crew risk is a driver for spacecraft design. Right now, the International Space Station is the benchmark for safety and protection from MMOD, but NASA wants to expand beyond it. Members of this panel noted that another area that needs improvement is information and data sharing across agencies and international lines.
When asked what some of the obstacles are to sharing MMOD-related data, an issue that was prevalent throughout the workshop, panelists suggested numerous reasons. One panelist explained how there is a tendency toward mission-specific solutions; a mission can be a driver for data sharing, but data sharing in and of itself is not necessarily useful. Another panelist said that figuring out the objective of data sharing is just as important as what is being shared, and who is involved is a challenge all of its own. Perhaps the greatest obstacle, though, is time. Gathering everyone involved to work out solutions is very time consuming, and there is no shortage of other pressing government challenges that all require serious attention. At the end of the session, some panelists noted that they were still not sure what are the greatest risks posed by debris, nor was it clear whether there has been a comprehensive risk assessment conducted about MMOD on a global scale.
The following observations were made by committee members following the workshop presentations in closed session and were then communicated to the audience and panelists within the hour, constituting the concluding portion of the workshop. As stated during the workshop, they should not be interpreted as findings or recommendations of the committee nor committee consensus, but rather, as the title suggests, observations from individual committee members following the workshop presentations and the subsequent discussions with the panelists and members of the audience.
• The committee heard that one of the NASA MMOD programs’ goals, if not the overriding goal, is to protect the space environment.
• The NASA MMOD programs have well characterized the threat posed by orbital debris and have influenced the space community and industry to take MMOD considerations into greater account in spacecraft designs and human spaceflight operations.
• There is uncertainty surrounding how to move forward with active removal of debris, and there does not appear to be an economic basis for orbital debris retrieval or removal. There seems to be a gap between policy and the capability to implement the policy.
• It remains unclear if a probabilistic risk assessment has been conducted that would help provide overall guidance for the programs, but such an assessment might be a useful activity.
• There are still some areas in which agencies working on MMOD issues are trying to structure a stronger regulatory framework, and this ongoing process should bear some fruit in coming years.
• U.S. foreign policy likes to set examples for other nations as a way of encouraging them to adopt procedures or guidelines that the United States believes are good and appropriate. There seems to be a fractured understanding across U.S. agencies as to their adoption, use, and clarifications of the MMOD guidelines, which became clearer throughout the workshop. If this improved understanding is further refined, the United States could provide a clearer example for other countries of how to structure similar governmental MMOD programs.
• The number and the variety of users of NASA MMOD programs, data, models, and services are impressive, with most of these interactions being carried out without formal contracts, compensation, or acknowledgment.
• If NASA moves forward with actual orbital debris retrieval, it will be a tremendous, time-intensive project.
• A lot of research needs to be done to improve the quality of conjunction assessment models.
• Conjunction analysis has gained greater prominence in the space community, and its use has increased over recent years. Nevertheless, despite U.S. Air Force efforts to provide more data to government agencies and industry on this matter, release of data appears inconsistent and infrequent, according to what was heard at the workshop.
• Engineering models like ORDEM2000 and BUMPER continue to be improved. If NASA could update publicly available models more frequently, the space community would benefit greatly in designing its own spacecraft with the most up-to-date information.
• The large differences between rules among the different agencies to satisfy MMOD guidelines are surprising.
• The fact that the 2010 National Space Policy focuses on the issues associated with orbital debris and is on target is impressive, despite the paucity of technical input in the policy formulation phase.
• Funding and personnel issues pose great challenges to NASA’s MMOD activities.
• Numerous national, international, and commercial entities have extensive spacecraft anomaly databases, yet, based on what was heard at the workshop, efforts to consolidate or summarize the data have been ineffective.
• Not having a single point of contact within NASA with authority over all MMOD program elements, modeling, and tool development appears to undermine ensuring the flexibility, consistency, quality, and relevance of priorities set across NASA.
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