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See detailLeveraging stretching directions for stationkeeping in Earth-Moon halo orbits
Muralidharan, Vivek UL; Howell, Kathleen C.

in Advances in Space Research (2022), 69(1), 620-646

Near Rectilinear Halo Orbits (NRHOs) are stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon ... [more ▼]

Near Rectilinear Halo Orbits (NRHOs) are stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon regime, the L1 and L2 NRHOs are proposed as long horizon trajectories for cislunar exploration missions, including NASA’s upcoming Gateway mission. The spacecraft, however, incurs continuous deviations due to unmodeled forces and orbit determination errors in this dynamically sensitive region. The current investigation focuses on an impulsive stationkeeping technique to maintain the spacecraft near a virtual reference orbit despite these uncertainties. The flow dynamics in the region are utilized to identify appropriate maneuver and target locations. The investigation reflects the impact of various factors on maneuver cost and efficacy. For orbits where position and velocity states are particularly sensitive to epoch time, an additional feedback control strategy is applied for phasing constraints. [less ▲]

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See detailDeparture and Trajectory Design Applications using Stretching Directions
Muralidharan, Vivek UL; Howell, Kathleen C.

Scientific Conference (2021, August)

Stable or nearly stable orbits do not always possess well-distinguished manifold structures that assist in departing from or arriving onto the orbit. Generally, for potential missions, the orbits of ... [more ▼]

Stable or nearly stable orbits do not always possess well-distinguished manifold structures that assist in departing from or arriving onto the orbit. Generally, for potential missions, the orbits of interest are nearly stable to reduce the possibility of rapid departure. The stable nature of these orbits also serves as a drawback for insertion or departure from the orbit. The Near Rectilinear Halo Orbits (NRHOs) and the Distant Retrograde Orbits (DROs) offer some potential long-horizon trajectories for exploration missions. The current investigation focuses on leveraging the stretching direction as a tool for departure and trajectory design applications. The magnitude of the state variations along the maximum stretching direction is expected to grow rapidly and, therefore, offers information for efficient departure from the orbit. Similarly, the maximum stretching in reverse time, enables arrival with a minimal maneuver magnitude. [less ▲]

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See detailOrbit Maintenance Strategy for Earth-Moon Halo Orbits
Muralidharan, Vivek UL; Howell, Kathleen C.

Scientific Conference (2021, February)

The L1 and L2 Near Rectilinear Halo Orbits (NRHOs) are proposed long horizon trajectories for cislunar exploration missions. Due to unmodeled forces as well as orbit determination errors in this ... [more ▼]

The L1 and L2 Near Rectilinear Halo Orbits (NRHOs) are proposed long horizon trajectories for cislunar exploration missions. Due to unmodeled forces as well as orbit determination errors in this dynamically sensitive region, the spacecraft deviates from the desired path. The current investigation focuses on an extended analysis of an impulsive stationkeeping technique to maintain the spacecraft near a long horizon virtual reference orbit. The dynamics in the halo orbit region are explored to identify suitable maneuver and target locations for stationkeeping. Furthermore, phasing constraints are incorporated to maintain spacecrafts on orbit where position and velocity states are sensitive to epoch time. [less ▲]

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See detailStationkeeping in Earth-Moon Near Rectilinear Halo Orbits
Muralidharan, Vivek UL; Howell, Kathleen C.

Scientific Conference (2020, August)

Near Rectilinear Halo Orbits (NRHOs) are stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon ... [more ▼]

Near Rectilinear Halo Orbits (NRHOs) are stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon regime, the L2 NRHOs offer candidate trajectories for the upcoming Gateway mission. The spacecraft, however, incurs continuous deviations due to unmodeled forces and orbit determination errors in this dynamically sensitive region. The current investigation focuses on a technique to maintain the spacecraft near a virtual reference orbit despite these uncertainties. For the stationkeeping scheme, flow dynamics in the region are utilized to categorically identify appropriate maneuver and target locations. The investigation reflects the impact of various factors on maneuver cost and efficacy. Additional feedback control is applied for phasing constraints. [less ▲]

Detailed reference viewed: 41 (3 UL)