Minimum-Fuel Powered Descent for Mars Pinpoint Landing
نویسندگان
چکیده
Motivated by the requirement for pinpoint landing in futureMarsmissions, we consider the problemofminimumfuel powered terminal descent to a prescribed landing site. The first-order necessary conditions are derived and interpreted for a point-mass model with throttle and thrust angle control and for rigid-bodymodel with throttle and angular velocity control, clarifying the characteristics of the minimum-fuel solution in each case. The optimal thrust magnitude profile is bang–bang for bothmodels; for the point-mass, the most general thrust magnitude profile has a maximum–minimum–maximum structure. The optimal thrust direction law for the point-mass model (alignment with the primer vector) corresponds to a singular solution for the rigid-bodymodel.Whether the point-mass solution accurately approximates the rigid-body solution depends on the thrust direction boundary conditions imposed for the rigid-body model. Minimum-fuel solutions, obtained numerically, illustrate the optimal strategies.
منابع مشابه
Capabilities of Onboard, Convex Powered-Descent Guidance Algorithms for Pinpoint and Precision Landing
The PDG (Powered Descent Guidance) algorithm provides a numerical method for onboard generation of guidance profiles for use during the powered-descent phase of Mars pinpoint or precision landing. The algorithm incorporates both state and control constraints, including minimum and maximum thrust limits, glideslope constraints to avoid impacting the surface, and speed and attitude constraints. T...
متن کاملG-FOLD: A Real-Time Implementable Fuel Optimal Large Divert Guidance Algorithm for Planetary Pinpoint
Introduction: Spacecraft accumulate large position and velocity errors during the atmospheric entry phase of a planetary mission due to atmospheric uncertainties and limited control authority. The powered descent phase, which is the last phase of Entry, Descent, and Landing (EDL), is when the lander makes a controlled maneuver to correct for these errors. This maneuver must be computed onboard ...
متن کاملMinimum-Landing-Error Powered-Descent Guidance for Mars Landing Using Convex Optimization
To increase the science return of future missions toMars and to enable sample return missions, the accuracy with which a lander can be delivered to the Martian surface must be improved by orders of magnitude. The prior work developed a convex-optimization-based minimum-fuel powered-descent guidance algorithm. In this paper, this convex-optimization-based approach is extended to handle the casew...
متن کاملGuidance, Navigation, and Control Technology System Trades for Mars Pinpoint Landing
Landing site selection is a compromise between safety concerns associated with the site’s terrain and scientific interest. Therefore, technologies enabling pinpoint landing (sub-100 m accuracies) on the surface of Mars are of interest to increase the number of accessible sites for in-situ research as well as allow placement of vehicles nearby prepositioned assets. A survey of various guidance, ...
متن کاملA Landmark Based Pinpoint Landing Simulator
Real-time position estimation for a descent lander is a critical technological need for many planned NASA missions. In particular, it enables the ability to land precisely and safely in a scientifically promising but hazardous site and is a key technology to be demonstrated by NASA in the next decade. The primary question of pinpoint landing is how to localize the lander by recognizing landmark...
متن کامل