Refueling Orbital Navigator for Active Debris Removal, and Asset Relocation, Recovery and Repair

There are two critical issues for in-space operations that would be addressed and potentially solved by the concept proposed here. These are: Active Debris Removal (ADR) and in-space maneuverability, e.g. providing mobility options to space assets, as well as in-space repair and reconstruction of disabled assets. There are many challenges associated with in-space maneuverability. Due to the high delta-V requirements, conventional chemical or propellant based systems are implausible, and only a reusable system is capable of keeping costs reasonable. It demands a specialized spacecraft that can maneuver between many target objects, rendezvousing, capturing and transferring assets into new orbits, or deorbiting unwanted space debris. Such an Orbital Transfer Vehicle (OTV) requires the ability to perform hundreds of km/s in delta-V over its mission lifetime. An OTV that can utilize in-situ upper atmospheric resources would enable a host of NASA and DoD missions that require extremely high delta-V in a fast, responsive, and repeatable manner. The Refueling Orbital Navigator (RON) spacecraft accomplishes this in the following way: first it employs a highly elliptical orbit to obtain fuel by scooping up and storing the molecular nitrogen and atomic oxygen encountered during the low altitude perigee periods of its orbit. As RON can thrust at apogee, it can achieve the extensive orbit lowering needed for ADR. Additionally, RON can thrust at perigee to provide drag compensation for low perigee refueling, stable non-Keplerian orbits, or rapid phase changes. In a recent effort at MSNW, funded by NASA's NIAC program, the design and the initial testing of the RON concept was successfully performed. It was determined that such a revolutionary system involved three key elements. The first was the adoption of Elliptic Collection Orbits (ECOs). In this way the collection of ambient atmospheric gases for propellant could be decoupled from the constant need for drag make-up that has effectively doomed prior efforts at air-breathing propulsion which typically employed circular orbits. The ECO limits the atmospheric drag to a brief period of time at perigee, but allows for solar energy accumulation and storage over the entire orbital period. This, combined with modern lightweight solar panel technology, make up the second critical element by creating a unique opportunity for lightweight, efficient, and high-power electric propulsion (EP) such as the Hall thruster to be employed. Finally, a highly efficient propellant collection system demanded by a refueling OTV can be achieved by a properly designed low-drag scoop geometry coupled to an active collection and storage system that employs turbo-molecular pumping. Such a collection and storage system has been devised and several key elements have been fabricated and successfully tested. Initial orbital dynamics calculations are presented as well as a sample mission analysis for the removal of a metric ton satellite from orbit.