NIAC Award: Crosscutting High Apogee Refueling Orbital Navigator for Active Debris Removal

Crosscutting High Apogee Refueling Orbital Navigator (CHARON) for active debris removal. (Credit: John Slough)

NASA Innovative Advanced Concepts (NIAC) Program
Phase I Award: Up to $125,000 for 9 Months

Crosscutting High Apogee Refueling Orbital Navigator (CHARON) for Active Debris Removal
John Slough

As of January 2018 an estimated 8,100 tons of space debris has accumulated in low Earth orbit consisting of spent rocket bodies, mission-related debris, and collision fragments. The vast majority of these objects are too small to detect with radar systems, but there are over 29,000 known objects larger than 10 cm. Impacts between these objects and operating missions have damaged costly equipment, required expensive collision avoidance maneuvers, and endangered the lives of astronauts on the international space station.

In 1979 the NASA Orbital Debris Program Office, in conjunction with Donald J. Kessler, released research on the “Kessler Syndrome” which predicted that collisions would continue to increase. This would lead to an exponential growth in debris that would render access to space impossible within several generations.

A partial solution to stabilizing the debris population was also proposed which required new missions to incorporate post mission disposal measures, as well as missions dedicated to Active Debris Removal (ADR) by placing the largest objects into decaying orbits of less than 25 years. This proposal addresses how one might succeed in achieving this latter objective.

Successful realization of the CHARON concept would have a major impact on several NASA mission objectives. An orbital vehicle that could utilize in-situ upper atmospheric resources would enable a host of missions, and in particular ADR, that require extremely high delta-V in a fast, responsive, and repeatable manner.

The concept proposed here, the Crosscutting, High Apogee, Refueling Orbital Navigator (CHARON) will provide such capability. CHARON accomplishes this in the following manner: first it obtains fuel by scooping up and storing the low density N2 and O encountered during the low altitude perigee periods of the highly elliptical orbits.

Incorporation of the ultra-lightweight, high thrust-to-power Electrodeless Lorentz Force thruster developed at MSNW enables CHARON to operate efficiently on stored gas in a variety of configurations depending upon mission requirements. As CHARON can thrust at apogee, it can achieve the extensive orbit lowering needed for ADR.

Additionally, CHARON can thrust at perigee to provide drag compensation for very low perigee refueling, stable non-Keplerian orbits, or rapid phase changes. CHARON requires only 5 kW of on-board solar power as energy collected during the higher altitude portions of its elliptical orbit can be stored for higher power operation later.

Functioning in this manner CHARON can generate 1.2 N of thrust at 2500 sec of Isp for ADR. During a 10 year mission life, CHARON will process 5500 kg of propellant to ferry 80 spacecraft, perform 850 degrees of plane change, with over 100km/s of delta-V, all with a single spacecraft launch, and requiring no additional onboard propellant.

As the largest concentrations of high mass debris are in the inclination band of 81 to 83 degrees and in the altitude range of 800 to 1300 km, it is removal of debris from these regions of space that will first be analyzed. Therefore, the phase I effort proposed here will focus on the mission analysis and orbit calculations for the retrieval of the more massive objects at a range of altitudes centered about 950km and 82 degrees inclination.

In addition, plans to experimentally determine the properties and behavior of various scoop designs for CHARON will be made. The more promising designs from the analysis will be fabricated and characterized in phase II. This is made quite doable by utilizing the large vacuum chamber and thrust stand at MSNW along with the newly constructed large aperture, LEO neutral flow generator.

Both drag coefficients as well as neutral compression ratios can be accurately determined in subscale testing which will allow for the design of the prototype CHARON that would be deployed for further space-based operation and development.

2019 Phase 1 and Phase II Selections
2011-2019 Consolidated List

  • duheagle

    Interesting. If I understand this proposal correctly, the idea is to use, bi-directionally, the same kind of orbital mechanics Beresheet recently used to raise its initial GTO orbit all the way out to the Moon. Using a ramscoop to incrementally accumulate needed reaction mass between rendezvous, grapple and de-orbit sorties is the key to economical long-term operation with no external logistics requirement beyond initial placement in orbit, radically lowering the cost per sortie.

    There are obviously some key details missing here, such as how these proposed “raptorsats” would physically grapple their prey, especially prey that is tumbling about one or more axes. But perhaps that is to be the subject of additional follow-on proposals.

    It would seem this technology, once matured, would be of use only for trackable debris objects, but it’s not like there is any shortage of such. Trackable debris also accounts, in sum, for the majority of the estimated total debris mass now whizzing about overhead, a percentage likely to only increase as “infant mortality” and “old age” cases from the many large LEO constellation projects now in the works deploy and either die young or live out their life cycles then fail to respond to de-orbit commands. Perhaps “hyenasats” would be a better name for the objects of this proposal as most of their future work might well eventually amount to circling large “herds” and cutting out and “consuming” the sick and the dead.

    With something like this new proposal accounting for trackable debris, sub-trackable debris could then be dealt with via laser sweepers – a number of proposals for which are now extant. Laser sweeping, at a given radiated beam flux, is most promptly effective on the smallest debris objects, taking progressively longer to de-orbit objects as they approach the mass of typical minimal trackable objects.

    This proposed technology, in combination with laser sweepers, could constitute components of an integrated high-low approach to dealing effectively and economically with the entire spectrum of debris objects. The existing population of debris objects would be taken down, then operations would transition to dealing with freshly generated debris on an on-going maintenance basis.

  • redneck

    Debris that is untrackable now may be trackable in the future as capabilities to use better tracking emerges. Some detection that is difficult from the ground may end up easy from 50km on a debris removal system.

  • Jeff2Space

    Interesting propulsion technology.

  • duheagle

    Agree. The new Space Fence is supposed to be able to track a lot of formerly untrackable stuff. But there will be optimal size and mass envelopes for any particular debris remediation technology. Laser sweepers will do best against small stuff. The technology described in this post will do best against trackable stuff, but there may be some lower bound where laser sweeping would be both faster and cheaper.

    This new technology requires a moderately lengthy sortie cycle per piece of debris removed. It will probably be best deployed against the largest pieces and/or the trackable pieces with the most problematic tracks. A laser sweeper would take a long time to de-orbit, say, a spent 2nd stage. But it could effectively de-orbit a very large number of dust-and-up sized debris objects very quickly via raster scans through particular volumes of space where the beam won’t impinge any active spacecraft.