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Space Debris Prevention for Small Spacecraft

Description:

Scope Title:

Onboard Devices for Deorbit and/or Disposal of Single Spacecraft

Scope Description:

Objective: Develop low size, weight, power, and cost (SWaP-C) active and/or passive onboard devices for deorbit and/or disposal of single spacecraft while also efficiently and effectively minimizing the probability of new orbital debris creation during the deorbit or disposal mission phase.

While the challenges posed by space debris and the management of large constellations within that environment are a multidimensional problem with multifaceted solutions, this subtopic scope focuses on technical solutions for the deorbit and/or disposal aspects that relate to the safe end-of-life operations of SmallSat swarms and constellations. The lifetime requirement for any spacecraft in LEO is 25 years post mission, or 30 years after launch if unable to be stored in a graveyard orbit [Ref. 7]. With increased use of higher orbital regimes by small spacecraft and regulatory attention on long-term debris concerns, it is critical that the small spacecraft community responsibly manage deorbiting and disposal in a way that preserves both the orbital environment and efficiency of small missions. Development and demonstration of low size, weight, power, and cost (SWaP-C) deorbit capabilities that are compatible with common small spacecraft form factors is required to maintain the agility of Earth-orbiting small spacecraft missions while complying with regulatory activity. These low SWaP-C deorbit or disposal technologies are being solicited in this scope. Furthermore, the active deorbit and/or disposal device technologies based upon fueled propulsion systems that make use of nontoxic fuels, "green propellants," are desirable technologies to reduce complexity in the spacecraft vehicle integration process, to maximize launch opportunities, and to encourage a “greener” space domain. In particular, deorbit/disposal technologies that enable even higher orbits than currently possible are desired. Further, technologies that actively or passively enable deorbit or disposal are desired, with consideration of potential risk for creation of new additional debris—that is, technologies that provide active or passive management throughout the disposal process to further protect against collisions and interferences with both active and inactive spacecraft and debris. 

Clear key performance parameters should be given as a part of the offeror's solution. These performance parameters (e.g., SWaP-C) should be quantified, compared to state of the art (SOA), and put into context of a planned, proposed, or otherwise hypothetical mission to highlight the advantages of the offered technology over SOA and other proposed solutions.

Expected TRL or TRL Range at completion of the Project: 2 to 5

Primary Technology Taxonomy:

  • Level 1 09 Entry, Descent, and Landing
  • Level 2 09.X Other Entry, Descent, and Landing

Desired Deliverables of Phase I and Phase II:

  • Research
  • Analysis
  • Prototype
  • Hardware
  • Software

Desired Deliverables Description:

In Phase I, a contextual study to further understand the feasibility of the proposed solution is desired. Ideally, Phase I would conclude with a basic proof-of-concept prototype (hardware or software as appropriate). Critical requirements and interfaces should be defined alongside refinements of the proposed key performance parameters in Phase I. The Phase I effort should provide evidence of the feasibility of key elements such as cost, assembly, integration, and operations. The concept should reach sufficient maturity to show strong feasibility for the defined mission environments and performance requirements. The prototype system design should reach sufficient maturity to define test objectives and map key performance parameters (mass, power, cost, etc.) from the prototype to the flight design. Hardware development during the Phase I effort should provide confidence in the design maturity and execution of the Phase II effort. Last, the Phase I effort should identify potential opportunities for mission infusion and initiate partnerships or cooperative agreements necessary for mission execution.

In Phase II, further development and technology maturation is desired. Ideally, Phase II would culminate with Technology Readiness Level (TRL) 5+ demonstration of the proposed solution. Both Phase I and Phase II should be approached with focus on infusion, ensuring solutions are being developed with the proper requirements, interfaces, performance parameters, partnerships, etc., such that they, through a Phase III award or otherwise, could be directly applied to real spacecraft and real missions.

State of the Art and Critical Gaps:

The 2020 NASA State of the Art of Small Spacecraft Technology report [8], Section 14.0, Deorbit Systems, gives a comprehensive overview of the SOA for both passive and active deorbit systems. The report details drag systems, including tethers, the Exo-Brake, and others. Drag sails have been the primary deorbit technology to date and have been developed, demonstrated, and even commercialized/sold for mission use. However, capability needs to continue to grow, especially for higher orbital applications with considerations to minimize the risk of new debris creation during the disposal phase of mission, as well as for more controlled deorbit and disposal. This subtopic, in the context of SmallSats, is of high importance to the Small Spacecraft Technology (SST) Program, the Agency, and the Nation in helping avoid a world that lives under the threat of the Kessler syndrome (i.e., exponential, catastrophic production of debris in orbit). Previous instances of this subtopic were focused on drag sails, but more investment is needed to help build and expand the ecosystem to include other onboard deorbit and disposal devices, as well as swarm/constellation management technologies, to help mitigate the risks (including considerations minimizing the probability of new space debris creation during the disposal phase of the mission) raised by the anticipated launch of many thousands more satellites in the years to come, most of which will be SmallSats.

Relevance / Science Traceability:

With increased use of higher orbital regimes by small spacecraft and regulatory attention on short- and long-term debris concerns, it is critical that the small spacecraft community responsibly manage deorbiting and disposal in a way that preserves both the orbital environment and the efficiency of small missions. Solutions are relevant to commercial space, national defense, and Earth science missions. 

References:

  1. Orbital Debris Mitigation and Challenges to the Space Community, J.-C. Liou, Chief Scientist for Orbital Debris, NASA, 58th Session of the Scientific and Technical Subcommittee, Committee on the Peaceful Uses of Outer Space, United Nations, 19-30 April 2021.
  2. U.S. National Space Policy, 1988.
  3. U.S. National Space Policy, 2020.
  4. Aerospace Corps, Space Traffic Management in the Age of New Space, 2018.
  5. State of Space Environment, H. Krag, Head of ESA’s Space Debris Office, 25 June 2019.
  6. Space Traffic Management in the New Space Era, T. Muelhaupt, Principal Director, Center for Orbital and Reentry Debris Studies, Center for Space Policy and Strategy, The Aerospace Corporation, Journal of Space Safety Engineering, Volume 6, Issue 2, June 2019.
  7. NASA. Process for Limiting Orbital Debris. 2012. https://standards.nasa.gov/standard/nasa/nasa-std-871914
  8. NASA State of the Art of Small Spacecraft Technology. 2020. https://www.nasa.gov/smallsat-institute/sst-soa-2020

Scope Title:

Autonomous Space Traffic Management Technologies for Small Spacecraft Swarms and Constellations

Scope Description:

Objective: Develop technological solutions for enhanced autonomous space traffic management that relate to the safe operations of SmallSat swarms and constellations, with the aim of reducing the strain on current space traffic management architectures.

While the challenges posed by space debris and the management of large constellations within that environment is a multidimensional problem with multifaceted solutions, this subtopic scope focuses on technical solutions for autonomous space traffic management aspects that relate to the safe operations of SmallSat swarms and constellations, with the aim of reducing the strain on current space traffic management architectures, particularly by removing the “human in the loop” and replacing it with faster decision-making autonomous systems; improving the accuracy of conjunction alerts, particularly reducing the number of “false alarms”; and ultimately reducing the risk of collision and the generation of orbital debris as a result of collisions with other spacecraft or debris.

As part of this scope, the following technologies are being solicited:

  • Low size, weight, power, and cost (SWaP-C) small spacecraft systems for cooperative identification and tracking: Development and demonstration of low SWaP-C and low-complexity identification and tracking aids for small spacecraft that can be scaled, produced, and readily standardized under the paradigm of small spacecraft ecosystems. With increased demands on existing space situational awareness capabilities, and with regulatory attention on the threat of spacecraft that are unidentified, misidentified, or too small to track, the small spacecraft community needs such technologies to allow the community to operate with lower risk to all spacecraft in orbit—without negatively impacting the efficiency of small missions—and to minimize the risk of space debris generation.
  • Low SWaP-C spacecraft systems for autonomous reactive operations of small spacecraft swarms and constellations: Development and demonstration of low SWaP-C small spacecraft technologies, such as sensors and coupled maneuvering systems, that enable small spacecraft swarms and constellations to operate in formation, in close proximity to other objects (cooperative or uncooperative), or beyond where the capacity of human-in-the-loop control will be required to process input onboard and execute correct responses autonomously, ensuring the safety of both spacecraft and object.
  • Supporting software modules that enable the above: Development and demonstration of software to be hosted aboard single spacecraft, across the spacecraft swarm/constellation, or on the ground, that enable the cooperative identification and tracking and/or autonomous reactive operations, and whose primary functions can be developed and demonstrated within the budget of standard NASA Phase I and II SBIR awards. This includes artificial intelligence/machine learning (AI/ML) techniques and applications that can enable autonomous orbit adjustment and other actions to mitigate the potential for in-orbit collisions. Also included are software applications and/or network applications that enable:
    1. Efficient information exchange between individual spacecraft.
    2. Minimal reliance on ground commanding.
    3. Efficient use of space-qualified computing architectures.
    4. High-precision swarm navigation and control.
  • Supporting ground systems that enable the above: Development and demonstration of ground systems that enable the cooperative identification and tracking and/or autonomous reactive operations, and whose primary functions can be developed and demonstrated within the budget of standard NASA Phase I and II SBIR awards.

In the above descriptions, the terms “SmallSat” and “small spacecraft” are to be interpreted as interchangeable and apply to Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA)-class spacecraft and below, including CubeSats, with masses of 180 kg and less. Where applicable, technologies that apply to CubeSats are highly desirable, as that would favor greater adoption of the technology.

In all of the above, clear key performance parameters should be given as a part of the offeror’s solution. These performance parameters (e.g., SWaP-C) should be quantified, compared to state of the art, and put into context of a planned, proposed, or otherwise hypothetical mission. Technologies that, in addition to performing the requirements outlined above, can also be ported from LEO to deep space environments—enabling new science and exploration SmallSat swarms/constellation-based missions—are highly desirable.

Expected TRL or TRL Range at completion of the Project: 2 to 5

Primary Technology Taxonomy:

  • Level 1 17 Guidance, Navigation, and Control (GN&C)
  • Level 2 17.2 Navigation Technologies

Desired Deliverables of Phase I and Phase II:

  • Research
  • Analysis
  • Prototype
  • Hardware
  • Software

Desired Deliverables Description:

In Phase I, a contextual study to further understand the feasibility of the proposed solution is desired. Ideally, Phase I would conclude with a basic proof-of-concept prototype (hardware or software as appropriate). Critical requirements and interfaces should be defined alongside refinements of the proposed key performance parameters in Phase I. The Phase I effort should provide evidence of the feasibility of key elements such as cost, assembly, integration, and operations. The concept should reach sufficient maturity to show strong feasibility for the defined mission environments and performance requirements. The prototype system design should reach sufficient maturity to define test objectives and map key performance parameters (mass, power, cost, etc.) from the prototype to the flight design. Hardware development during the Phase I effort should provide confidence in the design maturity and execution of the Phase II effort. Lastly, the Phase I effort should identify potential opportunities for mission infusion and initiate partnerships or cooperative agreements necessary for mission execution.

In Phase II, further development and technology maturation is desired. Ideally, Phase II would culminate with Technology Readiness Level (TRL) 5+ demonstration of the proposed solution. Both Phase I and Phase II should be approached with focus on infusion, ensuring solutions are being developed with the proper requirements, interfaces, performance parameters, partnerships, etc., such that they, through a Phase III award or otherwise, could be directly applied to real spacecraft and real missions.

State of the Art and Critical Gaps:

Current space traffic management architectures typically have a significant involvement of “humans in the loop” for the identification of conjunction threats, for making the decision on if and how to respond, and for implementation of the response. Currently the U.S. Air Force 18th Space Control Squadron provides conjunction advisories to virtually all space operators worldwide following measurements taken with its assets. The operators then assess and weigh the risks to their assets and the resources to be expended to mitigate those risks. This is a time-consuming process, typically on timescales that do not allow for rapid reaction to a rapidly evolving threat. It is further aggravated by the large uncertainties associated with the conjunctions, which can lead to many false alarms, resulting in an inability for operators to respond to all alerts, as it would consume too many resources, as well as “complacency that naturally occurs when the mission analysts are inundated with large numbers of alerts that turn out to be false alarms” [Ref. 4]. For instance, “under current tracking accuracies, the actual collision between Iridium-33 and Cosmos 2251 did not stand out from other conjunctions that week as being noticeably dangerous” [Ref. 4] and therefore was not acted upon, with the impact identified only after its occurrence.

To help address such situations, various stakeholders have been implementing solutions of their own, but these solutions are likely to run into limitations, particularly as more spacecraft are deployed and systems need to be scaled further and start interacting with each other:

  • For example, to help protect its nonhuman spaceflight assets, NASA established its Conjunction Assessment and Risk Analysis (CARA) program, with operational interfaces with the 18th Space Control Squadron to receive close-approach information in support of NASA mission teams. As a whole, however, the system still features humans in the loop, and if further investments are not made, it may run into combined scalability and time-responsiveness issues as more commercial and/or noncooperative foreign assets deploy and/or pass through the operational orbits of NASA spacecraft. While regulatory solutions are part of the mix to help resolve the issues encountered, such as the Space Act Agreement between NASA and SpaceX to identify how each party will respond [Ref. 7], those solutions are slow to implement and have legislative limitations. Technical solutions will inevitably be necessary to address gaps posed by regulatory means.
  • Deployers of SmallSat swarms and constellations are increasingly implementing software solutions for spacecraft to autonomously decide and implement collision-avoiding maneuvers. However, given the large capital and labor-intensive investment required to implement them, such systems may not be within the reach of all spacecraft operators, especially startup or single-spacecraft mission operators. Furthermore, with such technologies in their infancy, and with commercial operators racing to deploy and scale their spacecraft constellations to achieve market dominance, there is a very real risk that such systems may struggle to interface adequately with other autonomous and nonautonomous constellations, as was experienced by OneWeb and SpaceX [Ref. 8]. There may even be an enhanced collision risk as each autonomous system independently takes evasive action that, unbeknownst to the other, increases the risk of collision, much like two persons unsuccessfully trying to avoid each other in a corridor.

Relevance / Science Traceability:

  • Low-SWaP-C small spacecraft systems for cooperative identification and tracking: With increased demands on existing space situational awareness capabilities, and with regulatory attention on the threat of spacecraft that are unidentified, misidentified, or too small to track, the small spacecraft community needs low-SWaP-C identification and tracking aids. Employing such methods would allow the community to operate with lower risk to all spacecraft in orbit without negatively impacting the efficiency of small missions. There is a clear need to develop and demonstrate low-cost and low-complexity identification and tracking aids that can be scaled, produced, and readily standardized under the paradigm of small spacecraft ecosystems.
    • Technologies used for identification and tracking aids in LEO may also have extensibility to the growing number of cislunar missions.
  • Low-SWaP-C spacecraft systems for autonomous reactive operations of small spacecraft swarms and constellations: Small spacecraft operating in formation, in close proximity to other objects, or beyond the capacity of human-in-the-loop control will be required to process input onboard and execute correct responses autonomously.
    • These sensor-driven operations will be enabling for safe proximity operations with spacecraft or small bodies as well as the detection and reaction to transient events for observation, such as would be required for sampling a plume from Enceladus. Furthermore, enabling multiple small spacecraft operating in coordinated orbital geometries or performing relative stationkeeping can further expand human knowledge deeper into the universe by performing coordinated occultation, acting as virtual telescopes, and forming distributed apertures that would be prohibitively complex and expensive to launch into space as monolithic structures. Small spacecraft formation flight can also enable swarm gravimetry, synchronized observation of transient phenomena, and proximity operations for inspection of other assets.

References:

  1. Orbital Debris Mitigation and Challenges to the Space Community, J.-C. Liou, Chief Scientist for Orbital Debris, NASA, 58th Session of the Scientific and Technical Subcommittee, Committee on the Peaceful Uses of Outer Space, United Nations, 19-30 April 2021.
  2. U.S. National Space Policy, 1988.
  3. U.S. National Space Policy, 2020.
  4. Aerospace Corporation, Space Traffic Management in the Age of New Space, 2018.
  5. State of Space Environment, H. Krag, Head of ESA’s Space Debris Office, 25 June 2019.
  6. Space Traffic Management in the New Space Era, T. Muelhaupt, Principal Director, Center for Orbital and Reentry Debris Studies, Center for Space Policy and Strategy, The Aerospace Corporation, Journal of Space Safety Engineering, Volume 6, Issue 2, June 2019.
  7. https://www.nasa.gov/press-release/nasa-spacex-sign-joint-spaceflight-safety-agreement
  8. https://www.theverge.com/2021/4/9/22374262/oneweb-spacex-satellites-dodged-potential-collision-orbit-space-force

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