Engineering topics

Kathleen C Howell

Publications and source records attributed to Kathleen C Howell.

4 records

NASA NTRSDate not supplied

Recovery Traejctories for Inadvertent Departures from an NRHO

The current Gateway baseline orbit, a Near Rectilinear Halo Orbit (NRHO), is a nearly stable orbit that requires regular orbit maintenance (OM) maneuvers for long-term retention of a spacecraft. With missed OM maneuvers, particularly over extended intervals, spacecraft naturally depart from the baseline orbit. In response, a strategy to recover inadvertent departure trajectories and return a spacecraft to the NRHO is developed. A Monte Carlo-based approach is used to analyze departures that are recoverable using a standard OM approach. Dynamical structures in the vicinity of the NRHO are leveraged to design recovery trajectories for spacecraft that have departed further from the baseline.

Emily M Zimovan-Spreen↗

NASA NTRSDate not supplied

Cubesat Deployment from a Near Rectilinear Halo Orbit

Satellites deployed from the Gateway in a Near Rectilinear Halo Orbit (NRHO) must be safely delivered their desired destinations in cislunar space and beyond. The presence of simultaneously significant gravitational forces from the Moon, the Earth, and the Sun, along with the absence of atmospheric drag, complicates the mission design problem for cubesats deployed from the Gateway. The current investigation defines candidate green zones for safe satellite deployment, allowing a passive departing spacecraft to avoid recontact with the Gateway as it departs the NRHO vicinity.

NRHO↗

NASA NTRSDate not supplied

Debris Avoidance and Phase Change Maneuvers in Near Rectilinear Halo Orbits

Over the course of its lifetime, Ga teway may execute excursions from itsba seline NRHO that include short-lead maneuvers to avoid other spacecraft or debris objects or long-lea d rephasing within the NRHO to support rendezvous or other mission objectives. The dynamical cha racteristics of the NRHO a re distinct from those of low Ea rth a nd low luna r orbits due to the simulta neous gra vitational influences of the Ea rth a nd Moon. Thus, new a pproaches for executing debris a voidance ma neuvers a nd repha sing ma neuversa re necessary. The current investiga tion proposesmethods for designing low-cost DAMs with short-lead pla nning time a s well a s rephasing maneuvers with many months of advance notice.

Diane C Davis↗

NASA NTRSDate not supplied

Evolution of Astrodynamics for Multibody Environments, Numerical Precision and Dynamical Understanding

The innovative nature of dynamical systems theory and its applications in trajectory design enabled many recent missions by opening up new transfer and capture opportunities to meet mission requirements, reduce fuel costs, and address various launch constraints and contingencies. With a combination of proven numerical methods and an advanced understanding of the dynamics, an ‘experienced’ user can rapidly design multibody and cislunar missions such as Lunar IceCube and Artemis/Themis and relatively quickly conceive trajectory concepts for Sun-Earth mission orbits, such as the Space Weather Follow On-L1 Lissajous orbit—one that can be achieved and maintained.

David C Folta↗