{
  "patent_number": "US 9919813",
  "country": "US",
  "title": "How Spacecraft Calculate Maneuvers to Change Orbits Near Another Satellite",
  "original_title": "Control system and method for a plane change for satellite operations",
  "summary": "A mathematical method for onboard computers to calculate the precise engine burns needed for one satellite to change its orbital plane while moving relative to another satellite.",
  "what_it_does": "This patent describes a computational method for a secondary spacecraft to adjust its orbital path relative to a primary spacecraft. It uses a specific mathematical framework called the apocentral coordinate system to simplify the complex geometry of relative motion. By calculating the difference between a pre-maneuver velocity vector and a desired post-maneuver velocity vector, the system determines the exact impulsive velocity change (delta-V) required. This allows an onboard computer to automatically calculate the necessary engine burns to shift either the slant or the colatitude of the orbit without needing ground-based mission control.",
  "what_it_does_not_cover": [
    "Does not cover maneuvers that change both slant and colatitude simultaneously.",
    "Does not cover orbital changes for spacecraft that are not in a relative orbit around a primary spacecraft.",
    "Does not cover non-impulsive propulsion systems like continuous low-thrust electric ion drives.",
    "Does not cover maneuvers where the primary spacecraft is in an elliptical rather than circular orbit."
  ],
  "filed": "2016-04-15",
  "granted": "2018-03-20",
  "expires": null,
  "status": "active",
  "holder": "US Department of Navy",
  "holder_url": "https://patentbrief.org/company/us-department-of-navy",
  "inventors": [
    {
      "name": "Liam M. Healy",
      "url": "https://patentbrief.org/inventor/liam-m-healy"
    }
  ],
  "times_cited": 1,
  "tags": [
    "aerospace",
    "software"
  ],
  "abstract": "A spacecraft control system and method for determining the necessary delta-V and timing for impulsive maneuvers to change the plane of an orbit or the size of the orbit of a secondary spacecraft that is in an orbit around a primary spacecraft. The system and method uses an apocentral coordinate system for the relative orbital motion and geometric relative orbital elements to determine the required impulsive velocity change and time to maneuver, for relative orbital changes in which only one of slant or colatitude of the sinilaterating node changes.",
  "url": "https://patentbrief.org/patent/us/9919813/fairing-recovery-system",
  "markdown_url": "https://patentbrief.org/patent/us/9919813/fairing-recovery-system/md",
  "google_patents_url": "https://patents.google.com/patent/US9919813",
  "relatedPatents": []
}