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Recommendations on 

Trust and Interoperability in Space Situational Awareness Data

National Space Council Users’ Advisory Group 

Technology and Innovation Subcommittee

September 2, 2020

The content of this paper reflects the thoughts and opinions of the subcommittee’s 

authors, and should not be construed as a recommendation of the full National Space 

Council Users’ Advisory Group or the official policy of the United States Government, 

the National Space Council, or the National Aeronautics and Space Administration
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Purpose

Space Policy Directive-3 (SPD-3), National Space Traffic Management Policy, was issued by the 

White House on June 18, 2018. The first goal in SPD-3 is to advance Space Situational Awareness 

(SSA)1 and Space Traffic Management (STM) Science and Technology. SPD-3 states, “The 

United States should continue to engage in and enable S&T (Science and Technology) research 

and development to support the practical applications of SSA and STM. These activities include

... advancing the S&T of critical SSA inputs such as observational data, algorithms, and models 

necessary to improve SSA capabilities, and developing new hardware and software to support data 

processing and observations.” In response to SPD-3, the National Space Council’s User Advisory 

Group (UAG) Technology and Innovation Subcommittee has been studying technical issues 

around SSA data by consulting a number of experts in government and industry. There are many 

U.S. Government (USG) stakeholders in SSA data, including the Department of Defense (DoD), 

Intelligence Community (IC), National Aeronautics and Space Administration (NASA), 

Department of Commerce (DOC), Department of Transportation, and Department of State. The 

ability to continuously observe and track space object locations (referred to as SSA) is absolutely 

fundamental to critical capabilities such as orbital debris tracking and/or removal, monitoring safe 

operations in space for domestic regulatory purposes, and international security and transparency

in the space domain. A whole-of-government approach is needed to address these challenges. 

This document summarizes two key recommendations from the UAG, and several observations.

Background

The United States Space Command (USSPACECOM) mission is to deter aggression and conflict, 

defend U.S. and allied freedom of action, deliver space combat power for the Joint/Combined 

force, and develop joint warfighters to advance U.S. and allied interests in, from, and through the 

space domain. As such, it plans, integrates, conducts, and assesses global space operations, and 

tracks all space objects using DoD -certified space and Earth-based optical and radar systems,

providing missile warning capabilities and space object orbital location information for the 

protection of space assets. These certified sensors make up the Space Surveillance Network 

(SSN). Currently USSPACECOM also has responsibility for notifications of potential impending 

near misses or collisions of space objects to commercial, government, domestic and international 

spacecraft operators. This includes maintaining a “catalog” of known positions of space objects 

available to operators and researchers via a global public service (https://www.space-track.org), 

although some information may be redacted for national security reasons. This catalog has a wide 

variety of domestic and international users to include industry, government(s), and academia.

Currently the orbital catalog only incorporates data from sensors certified by DoD, although 

USSPACECOM does have access to other sensor data. The DoD also has more than two dozen 

government-to-government agreements under which enhanced space object location data is 

provided beyond the publicly-available catalog.

1 The DoD uses the term “Space Domain Awareness (SDA)” but this is not yet in broad use.
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SPD-3 acknowledges the need for the DoD to focus on maintaining access to and freedom of action 

in space, and states that the DOC should be the focal point for administering an open data 

architecture repository and providing space collision avoidance support services. As the DoD has 

already found, the technical challenges to providing this type of service have been increasing to 

the extent that the approach must also change to meet them.

There has been rapid growth in the number of space objects such as large commercial 

constellations. Adding large numbers of satellites noticeably increases the likelihood of collisions2

and increases computational complexity for collision calculations. Additionally, there are

proliferating dynamic capabilities such as rendezvous, satellite servicing, and more frequent relocation of satellites. Natural and human-made space threats have been growing. Continuous, 

persistent tracking and custody of space objects is not possible today with the widely-spread SSN.

Very small orbital debris that are nonetheless still a danger cannot be tracked (much less removed), 

and satellite maneuvers are confirmed hours or even days after they occur. This is further 

complicated by launches with hundreds or more spacecraft deployments from a single mission.

This is increasingly becoming routine for U.S., Indian, Russian, and Chinese launches. In order 

to provide meaningful and timely situational awareness, the DoD and DOC will need to 

incorporate more multi-sourced information, data science, and analytics in their data repositories, 

and allocate or request budget to support.

There has been significant growth in global commercial and government entities using their own 

sensors to observe orbiting space objects. National security sensors will of course continue to 

support the DoD, but can feed into a DOC SSA system which also incorporates international 

partner and commercial data. The DoD is interested as well in using international partner and 

commercial data to supplement the SSN for greater space domain awareness. There are two 

challenges highlighted in this paper. First, a major obstacle to incorporating data from commercial 

and international sensors that are not certified by the DoD is trust in the reliability and accuracy of 

the data. Second, with so many stakeholders and a transition of certain responsibilities between 

the DoD and DOC, major inefficiencies in STM may occur from uncoordinated, inconsistent, and 

incompatible approaches to SSA data.

Trust and Interoperability

The United States Space Force (USSF) has undertaken a number of activities to evolve its own 

command and control system and learn how best to build trust and incorporate commercial SSA 

data. The DoD has created a Unified Data Library along with an SSA data storefront where data 

are made available to “any partner organization.”3 The models and algorithms used to propagate 

this data and determine orbit prediction from past observations are contained within the 

Standardized Astrodynamics Algorithm Library. The USSF recently announced it would share

this data with the United Kingdom’s Ministry of Defence4. USSPACECOM is currently providing 

2 NASA Large Constellation Study, Orbital Debris Quarterly News, Volume 22, Issue 3, September 2018 3 https://breakingdefense.com/2019/10/air-force-hires-startup-to-build-up-mdos-unified-data-library/ 4 https://www.c4isrnet.com/battlefield-tech/space/2020/08/18/space-force-to-begin-sharing-technical-space-datawith-uk/
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non-traditional sensor (i.e., not from sensors in the SSN) data inside the Combined Space 

Operations Center (CSpOC) and the National Space Defense Center (NSDC). While these nontraditional data are not integrated with data generated from the SSN, they provide additional insight 

and information which is being referred to during daily operations. There are active efforts to 

perform operational and engineering exercises supporting evolution to the next level of situational 

awareness and command and control. The DOC, Air Force Research Lab (AFRL), and 

USSPACECOM Joint Task Force recently conducted a global space traffic management exercise 

which successfully demonstrated the benefits of 24-hour global combined operations and shared 

data from commercial, foreign, military and civilian participants. Efforts are also underway by the

USSF to develop the capability to ingest allies’ space data more quickly5.

The Defense Advanced Research Projects Agency (DARPA) has also made technology 

investments to facilitate non-traditional SSA data incorporation. In 2016, DARPA‘s 

OrbitOutlook (O2) program demonstrated the ability to validate the quality of non-traditional 

sensor sourced SSA data in real time.

6 However, according to briefings from experts, the 

demonstration software was not optimized for larger scale multi-source data uptake, and the 

software was not immediately ready to transition to operational use. Some of the algorithms and 

methods have been published and incorporated into other efforts7,8

. An interesting lesson was 

learned from a subsequent DARPA program started in 2018 called Hallmark, which demonstrated

sophisticated SSA tools and command and control capabilities9

. Hallmark illustrated an approach 

to rapid software acquisition which, according to program experts, has been welcomed by key 

partners in the national security SDA/SSA enterprise. During the program, it became clear that 

software-as-a-service10 is having a substantial impact on how software services are being acquired. 

Private industry is driving this revolution; it’s not clear how the changing business model will 

affect data and software architecture compatibility for USG programs, or the ability to shift to a 

new provider.

There appear to be few major technical barriers to the incorporation of commercial and 

international data. However, the USG must understand how to continuously evolve capabilities to 

keep up with changes in space operations (such as the expansion to cis-lunar space) and also 

provide best-in-class government services that are distinct from commercial offerings. The risk is

that if the DOC and USSF choose incompatible data architecture approaches, data sharing and 

coordination (such as exists today between the DoD and Federal Aviation Administration [FAA]

air traffic management) will be greatly hampered. The DOC should actively seek lessons learned 

from both the air traffic management paradigm and understand the DoD’s rapidly evolving 

approach to data modeling, engineering, management, software acquisition, and curation 

architectures.

5 Conversation with SMC Special Programs Directorate Space Domain Awareness Division 6 http://www.amostech.com/TechnicalPapers/2016/SSA-Algorithms/Raley.pdf 7 https://doi.org/10.1016/j.actaastro.2018.12.043 8 http://arc.aiaa.org/doi/abs/10.2514/1.G002230

9 https://www.darpa.mil/news-events/2020-03-27 10 https://en.wikipedia.org/wiki/Software_as_a_service
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Presently, commercial SSA capabilities are primarily sustained by USG purchases and going 

forward the DoD and DOC will continue to be significant customers of the industry. They must 

work together to avoid incompatible approaches so industry can organize around the products that 

will be needed by both organizations. American taxpayers should not be paying twice for 

substantively the same data in different forms due to a lack of coordination inside the USG.

However, the long-term viability of a commercial marketplace for SSA data is still uncertain and 

could be at risk if the DoD and DOC do not define their needs in a timely manner. The DoD and 

DOC must define how much data is needed and develop a long-term strategy about the commercial 

SSA industry to clearly scope the government market limits, and/or help increase the commercial 

customer base.

Recommendation #1: The Departments of Defense and Commerce should work to create an 

interoperable approach on multi-sourced space data modeling, data sharing, and curation 

architectures. Both departments should study lessons learned and fund studies and research around 

technical solutions and processes that allow incorporation of properly vetted international and 

commercial data into the space object catalog for military, civil and commercial uses. We further 

recommend that the Departments should report to the National Space Council regularly on their 

progress.

Standards to Accelerate and Simplify Interoperability and Trust Approaches

The advent and growth of commercial earth remote sensing entities (many international) has 

required the issue of trust to be addressed by the National Geospatial-Intelligence Agency (NGA) 

and others in the IC. Mr. Dave Gauthier, Director of NGA’s Commercial & Business Operations, 

explained to the subcommittee that the USG, as a regulator, requires basic data protection 

standards on commercial remote sensing operators licensed by the DOC. This is documented in a 

data protection plan, and periodically the USG checks the data submitted and the commercial 

physical infrastructure to validate adherence to the plan - similar to an audit of a manufacturing 

“supply chain.” This regulatory requirement is largely in place to ensure that commercial 

spacecraft operating under a “U.S. flag” are able to maintain safe operations on-orbit and will not 

bring undue harm to national security. 

In addition, the USG, as a data customer, holds commercial data providers to even higher standards 

through contractual language. This is documented in a security plan for each contract which 

documents the supply chain for the digital information sold to the USG. The security plan includes

what networks transfer data, whether it is encrypted vs. unencrypted, who owns the network used 

(especially foreign owned or with foreign investors), how the data are protected in storage, and 

who applies analytics to the data. Mr. Gauthier identified two key challenges NGA has 

encountered with this approach. First, in some cases the slow pace of building up to full 

compliance can delay government access to critical data. Second, there is a need to broadly 

communicate the best practices in data supply chains to industry much earlier in their business 

development and design phases. This is because retroactively applying proper data security 
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measures to commercial infrastructure is at a minimum more costly and at a maximum may not 

even be possible. 

The National Institute of Standards and Technology (NIST) has done work around data protection 

standards that may be applicable. The IC’s Commercial Remote Sensing Working Group 

(CRSWG), currently chaired by Mr. Gauthier, recently proposed Enhanced Data Protection 

Requirements to establish guidelines and measures to protect and defend commercial imagery, 

data, and products by establishing standards for trust. These requirements would use USG

standards from NIST and preserve the DOC licensing decisions while protecting the U.S. national 

security interests. This initiative builds off the NIST SP 800-17111, with pre-tailored security 

controls, and avoids generating a new security standard document. It allows for reciprocal 

community risk assessment and authorization (A&A), resulting in creation of a commercial 

“trusted environment” protecting USG data that has the capability of obtaining a third-party 

certification. This will leverage the commercial providers’ profit driven, diverse environment (i.e. 

non-U.S. personnel, overseas ground stations, foreign partners, foreign code, outsourced support), 

while balancing performance, cost, and security. 

Experts have also commented on the need for a standard method for quantifying SSA sensor

uncertainty. SSA data are provided with a covariance matrix that describes the uncertainty in the 

orbital position of the space object, but does not describe the quality of, or uncertainty in, the 

sensor data used to calculate that position. A standard method of expressing and comparing sensor 

uncertainty would assist all entities in characterizing the quality of their data - essential for trust. 

There has been relevant research in the community regarding improved methods of uncertainty 

quantification and representation12. Clarity on all aspects of data vetting must be agreed to by the

DoD and DOC to establish thresholds for accepting the data for inclusion into the space object 

catalog. Establishing standards for sensor uncertainty also provides clarity for SSA businesses 

and international partners alike and potentially could greatly speed up the data quality vetting 

process.

The Consultative Committee for Space Data Standards (CCSDS) is a multi-national forum for the 

development of communications and data systems standards for spaceflight. It was founded in 

1982 by the major space agencies of the world. NASA is very involved with CCSDS and also in 

the area of orbital debris tracing and monitoring, and offers substantial technical expertise and 

international perspectives on data standards. The DOC and DoD should leverage NASA’s long 

history of expertise with standards and experience with the international community to avoid 

duplication and enable the harmonization of the DOC and DoD emerging standards with existing 

global standards. 

Recommendation #2: The Department of Defense, Department of Commerce, and NASA should 

work to jointly develop standards for space data protection and security plans, space data 

verification, and space data uncertainty quantification.

11 https://csrc.nist.gov/publications/detail/sp/800-171/rev-2/final 12 Bever, M., Delande, E., Jah, M. (2019). “Outer Probability Measures for First and Second Order Uncertainty in

the Space Domain” IAA-AAS SciTech-040, Moscow, Russia June.
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Observations on Additional Areas of Study to Consider

In addition to these recommendations, there are several points that have been raised by the many 

technical experts we have consulted, including Mr. David Gauthier (NGA), Prof. Moriba Jah 

(University of Texas at Austin), Dr. Jeff Kommers (Ball Aerospace), and Dr. Jerry Krassner 

(independent consultant). The T&I Subcommittee makes the following observations:

1. The sensitivity of SSA data to specific types of errors depends on complex, 

multidimensional mathematical and physical relationships. A study to understand which 

parameters are most/least important to the quality and precision of the data, especially 

related to information needed for different use cases (see item d below), would be 

beneficial.

2. A frequent re-visit rate for observing space objects will also reduce risk, as new data 

sources can correct errors or more rapidly highlight spoofing. A study to understand the 

quantity, quality, type, and modality of sensors needed for persistent custody of objects 

would be helpful to the USG. Rules for the continuous validation of less-trusted data 

sources via coincident collection with trusted sources can mitigate risk.

3. In other domains, fusion of dissimilar data can create synergy, greatly increasing the 

precision of the combined information and reducing the risk of accepting any single source 

of data. A study to evaluate the best mix of optical, radar, laser, and other data may provide 

insight into how much of which data is optimal.

4. There are a variety of uses for SSA data, such as collision avoidance, identification, and 

behavior prediction. Some uses require timeliness over accuracy, and other uses may 

reverse the priorities. Some data may be acceptable even if not of the highest quality or 

vetted to the highest standards because of timeliness. Defining those use cases, and 

deciding ahead of time what data from what source will be accepted would be beneficial 

to both industry and government

5. As identified in SPD-3, there is a critical need for SSA research, to establish capabilities 

for developing trust in multi-sourced information, including unstructured data such as 

human-based semantic (non-numeric, text-based) information.

6. The long-term viability of the business model for commercial SSA data is not yet clear. 

The USG should scope its needs and communicate what is needed clearly to industry to 

ensure entrepreneurs and investors understand the size of the USG market. The USG must 

also provide clarity around its standards of service going forward to enable commercial 

product differentiation.

7. Currently, international space data are being aggregated and shared in a variety of ways. 

The Minor Planet Center of the International Astronomical Union (IAU) has aggregated 

optical and radar tracking measurements of asteroids and comets for over 70 years, from 

professional and amateur observatories. Techniques developed there for managing 

uncertainty and trust in data from diverse sources can be applied to the SSA effort. Orbital 

position computations require fundamental earth positional data that are aggregated by the 

International Earth Rotation Service (IERS) located in Paris, France using data from 
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observatories around the world. A study could look at these successful models for insight 

into an approach to international SSA data pooling.

Closing Thoughts on U.S. National Interest

Despite the very high quality of individual sensors in the SSN, the U.S. is unable to maintain 

persistent custody of all space objects. This affects the quality of the current space object catalog, 

resulting in risks to government and commercial space operators. This is one reason other 

countries are pursuing development of their own catalog capability.13

The U.S. is currently the world leader in SSA, but a lack of coordinated effort may soon cause us 

to fall behind. We have learned from the space-based synthetic aperture radar (SAR) commercial 

experience that operational limitations put on industry will only lead to other countries taking 

leadership in these capabilities. If we lose leadership in this critical arena, we will have less 

influence in overall domestic and International space operations, which will impact our ability to 

be the leader in spaceflight development.

Increased trust and collaboration across the SSA enterprise enables closer collaboration and trust 

amongst allies and presents new options for diplomatic engagement with other participants. A 

whole-of-government approach with clarity on roles and responsibilities is needed to enable a host 

of urgent needs in secure and sustainable operations in space for the United States, our industry,

and our allies.

13 Lal, B., Balakrishnan, A., Caldwell, B.M., Buenconsejo, R.S., Carioscia, S.A. Global Trends in Space Situational 

Awareness (SSA) and Space Traffic Management (STM), Institute for Defense Analyses Science and Technology 

Policy Institute Document D-9074, April 2018.

The content of this paper reflects the thoughts and opinions of the subcommittee’s 

authors, and should not be construed as a recommendation of the full National Space 

Council Users’ Advisory Group or the official policy of the United States Government, 

the National Space Council, or the National Aeronautics and Space Administration