Flight Mechanics Feasibility Assessment for Co-Delivery of Direct-Entry Probe and Aerocapture Orbiter

Motivated by a need for lower-cost planetary science missions to Mars, this study considers the problem of co-delivering a network of small rough landers to the Martian surface such that the probes are placed on different entry trajectories by a single carrier spacecraft without requiring translational maneuvers between probe deployments. The Small High Impact Energy Landing Device is used as a reference design, and a flight-mechanics analysis is performed to ensure requirements are met under the influence of relevant uncertainties. A linearized targeting method is developed and applied to design probe jettison velocities for a regional probe network. Monte Carlo analysis shows that a regional network approximately 100 km in scale could be passively co-delivered with limited deformation of the network shape despite the influence of relevant uncertainties, and linearized targeting errors are quantified. Nonlinear numerical optimization is applied and enables the design of probe jettisons for co-delivery of larger-scale networks. Additional Monte Carlo analyses quantify the rate at which delivery error increases with network scale.

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Relative Motion in the Velocity Frame for Atmospheric Entry Trajectories

Albert

Schaub

2023

Journal of Spacecraft and Rockets

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Relative motion models provide a method of directly describing the position and velocity of a deputy spacecraft with respect to a chief spacecraft. Common approaches such as the Clohessy–Wiltshire equations describe relative motion in a rotating orbit frame aligned with the radial position vector of the chief, and intuitive solutions exist in this frame for circular or near-circular chief orbits. However, as eccentricity of the chief orbit increases, the along-track and velocity directions become less aligned and the orbit frame becomes less intuitive. This work revisits several key relative motion descriptions in the orbit frame and reformulates them to describe motion in the velocity frame, which provides an intuitive description of motion with respect to the flight path. Highly elliptic and hyperbolic chief motions are considered, which are common for atmospheric entry trajectory scenarios. These models are combined with the extended Allen–Eggers equations into a procedure for analytically estimating the offset in landing location for formation flying on an atmospheric entry trajectory. Three representative examples are given and compared with simulation, and range offset predictions are within 6% of total chief range in all cases.

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Flight Mechanics Feasibility Assessment for Co-Delivery of Direct-Entry Probe and Aerocapture Orbiter

Cited by 5 publications

References 29 publications

Mars orbit injection via aerocapture and low-thrust nonlinear orbit control

Mars orbit injection via aerocapture and low-thrust nonlinear orbit control

Co-Delivery of a Martian Probe Network

Relative Motion in the Velocity Frame for Atmospheric Entry Trajectories

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