Diane Davis: "The Great Gateway Escape: Dynamics of Jettisons from the Lunar Gateway"

Bio: Dr. Diane Davis is an astrodynamicist whose career has included navigating spacecraft to Mars at the Jet Propulsion Laboratory, working on mission control ground system development for the ISS, and leading the Gateway mission design team at Johnson Space Center. She has a BS in Physics from Texas A&M University, an MS in Astrodynamics from the University of Texas at Austin, and a PhD in multibody Astrodynamics from Purdue University. Her research focuses on orbit maintenance and dynamics of departing flow in cislunar orbits. Diane is a fellow of the American Astronautical Society, an associate fellow of the American Institute of Aeronautics and Astronautics, and a member of the International Astronautical Federation Astrodynamics Committee.

Abstract: The Gateway at the Moon will be the next human outpost in space: a proving ground for deep space technologies and a staging location for missions to the lunar surface and beyond. With crew visits every year, the Gateway will be constructed over time as various components arrive with Orion or are sent independently without crew presence. Naturally, spacecraft and objects of various descriptions will also depart the Gateway for other destinations. Examples include Orion carrying the crew back to Earth, cubesats deployed to locations in cislunar space, discarded logistics modules or lunar landers headed to heliocentric space, and the Gateway itself when its lifetime is complete. Each departing object must leave the vicinity of the Moon without risking collision with the Gateway or other spacecraft in the vicinity, and it must be delivered safely to its selected destination despite unavoidable operational errors and uncertainties. Each departure is governed by the dynamics of the Gateway orbit and the cislunar environment.

The Gateway orbit is a southern 9:2 Near Rectilinear Halo Orbit (NRHO) near the Moon. This NRHO is nearly stable, but over time, any unmaintained object in this orbit departs due to small instabilities. A jettison maneuver speeds the departure from the NRHO, but the effects of the maneuver on the spacecraft behavior depend on the location, magnitude, and direction of the burn. The chaotic nature of the dynamics in cislunar space complicates the selection of a jettison maneuver to achieve a desired final destination. In this presentation, the challenges associated with deployment from the Gateway are discussed, and visual methods are used to overcome these difficulties and successfully design safe, effective departure trajectories from the Gateway halo orbit.