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Moving the Space Sustainability Needle? Assessing the new NASA Orbital Debris Mitigation Standard Practices
By Charity Weeden, VP of Global Space Policy
In December 2019, after months of interagency deliberation, NASA released an updated version of the U.S Government Orbital Debris Mitigation Standard Practices (ODMSP). The last version had been promulgated in 2001, in an era before the 2007 Chinese ASAT test or the 2009 collision of Iridium 33 and Cosmos 2251. It was a time where commercial utilization of space was predominately in the geosynchronous region, save for the newly revived Iridium business that leveraged its constellations of 66 satellites or a small number of geospatial platforms prior to the 2003 U.S. remote sensing policy that would open the “aperture” to new space-based remote sensing businesses. It was also a time where only about 40 countries had experience operating satellites, half as many as today.
ODMSP are meant for U.S. Government satellite operators – NASA, NOAA, USGS, DoD, and Intelligence Community – and the standard practices will be embedded into regulations of commercial operators as well, making the rules effective for all spacecraft which fall under U.S. jurisdiction. However, a standard practice loses its global effectiveness if only adhered to by one country and these practices still need to be embedded through world-wide operational best practices. Now, the U.S. has the complicated task of convincing the international community to adopt its updated practices through IADC, UN COPUOS, bilateral and multilateral dialogue. Per the 2019 ODMSP, it “provides a reference to promote efficient and effective space safety practices for other domestic and international operators.”
Why did the ODMSP need to be updated?
The drastic increases in activity and congestion throughout all orbits over the past 20 years has necessitated policy measures first in 2010 through the National Space Policy and now through Space Policy Directive – 3 (SPD-3), enacted in the National Space Traffic Management Policy of the United States in 2018. SPD-3 clearly addresses the concern with current guidelines, stating that the ODMSP were “inadequate to control the growth of orbital debris” and that, “The United States should develop a new protocol of standard practices to set broader expectations of safe space operations in the 21st century” that includes “operating practices for large constellations, rendezvous and proximity operations, small satellites, and other classes of space operations.”
With the goal of developing a new protocol of standard practices, what exactly was updated in the ODMSP? Here are some significant items:
- It’s more empirically oriented. The updated version includes quantitative, probabilistic, and reliability limits to many elements of the document thus creating clearer lines with which to assess compliance.
- It introduces the concept of 100 object-years. At first glance, this calculation may seem confusing. However, it is spelled out in NASA Standard 8719.14B (updated in 2019), section 4.3.4.3 which clarifies how it is expected to be used. Specific to LEO, it is the product of the number of pieces of debris released and the length of time expected to naturally deorbit into the atmosphere, which is based on perigee of the debris. In the new ODMSP, this concept of 100 object-years is applied to planned debris creation and for objects smaller than a 1U cubesat. If an operator plans to eject four pieces of debris, they should do this at a perigee that takes less than 25 years to re-enter earth’s atmosphere. If an operator plans to send up 100 picosatellites, they must deorbit all of those objects within one year from the appropriate altitude (in this case, much lower than the ISS).
- It expands and re-arranges the types of options for post-mission disposal. The 2001 ODMSP had three main options to consider when disposing of a space object after the end of mission: direct re-entry into the atmosphere, maneuver to a storage orbit, or direct retrieval. Now, direct re-entry and jettisoning the object into a heliocentric or Earth-scape orbit is mentioned first, with atmospheric reentry, storage between LEO and GEO, storage above GEO, and direct retrieval within five years of end of mission. A reliability minimum of disposal is set at 90%, with a goal of 99% or higher.
- It introduces practices for classes of space operations. Large constellations, small satellites, rendezvous, proximity operations and servicing, and active debris removal are all newly mentioned. Practices for these classes include minimizing accidental collision, explosion, or fragmentation. However, there are some more detailed items identified such as the direct entry disposal method being preferred for large constellations (100 or more). This would need to be completed with a minimum reliability of 90%.
How does the 2019 ODMSP compare to the 2001 version?
It mentions new orbital activities, applying the same key practices as for traditional satellites. Additionally, it provides numerical limits on items that were difficult to assess and encourages operators to go above the minimums outlined. A key final condition is that the USG will update and refine these practices as necessary.
It is good that the door is left open for additional revisions as there are items that the next version should consider. First, the ODMSP are intended for nominal operations only. If a satellite has a design flaw, that is if it experiences an anomaly of any sort and is unable to fulfil its disposal requirement, the ODMSP would not apply. This is a gap that must be addressed to ensure operators consider the consequences of leaving defunct spacecraft (both rocket bodies and satellites) in orbit. These are the type of debris that have the potential to do the most damage and therefore, backup disposal practices should be strongly encouraged.
Additionally, the time to de-orbit guidance did not change and remains at a maximum of 25-years. The commercial space community is starting to take up the practice of five years or as-soon-as-possible. Clearly, more discussion is required on this element. Given the focus on better empirical assessment, there should be studies conducted that include external experts to help more precisely evaluate the impact of deorbit timeframes.
Finally, NASA should track compliance with these practices within the USG, and regulators should do the same for commercial entities, providing that data to the public. Such transparency will show leadership in the global community on adherence to best practices and can be seen as an implementation of the recently adopted UN COPUOS long-term sustainability guidelines. Without compliance, these standard practices do not achieve the effect they were designed to achieve.
ODMSP and other current practices such as those that stem from IADC and UN COPUOS represent the minimum necessary to maintain space sustainability, based on current knowledge. What we are still unsure of is precisely how greater numbers of space objects will impact the space environment. Will they be maneuverable? Will they break in orbit? Will they have adequate space situational awareness or robust traffic management to better avoid collisions? Will they even follow best practices?
Additionally, debris on debris collisions will have a greater impact in a more congested environment. This may be a lower probability event, but it comes with large consequences. Today’s state of the art technologies predict these collision possibilities with inadequate accuracy a maximum of seven days out. That’s not a lot of time to rally up a solution to mitigate an impending collision. Remediation of the space environment – that is, removing large, impactful objects – is a complementary and necessary element of this discussion and SPD-3 takes this into consideration directly after discussing an ODMSP update: “The United States should pursue active debris removal as a necessary long-term approach to ensure the safety of flight operations in key orbital regimes. This effort should not detract from continuing to advance international protocols for debris mitigation associated with current programs.”
What is now needed is a culture of safety and compliance throughout the global space community and there are many opportunities available to achieve this. Efforts such as the Space Safety Coalition Best Practices for Sustainability of Space Operations and the World Economic Forum’s Space Sustainability Rating underscore the trend to go above and beyond minimums for spaceflight safety as do other practices such as designing spacecraft for post-mission disposal in the event of anomalies.
The space environment is in the midst of a step function in congestion and orbital risk. All operators must play a positive role in ensuring we leave no trace by complying with – no – by exceeding standard practices.
