AIAA 98-4574 Numerical Roll Reversal Predictor-Corrector Aerocapture and Precision Landing Guidance Algorithms for the Mars Surveyor Program 2001 Missions

This paper describes guidance algorithms that use numerical predictor-corrector techniques to guide the spacecraft to the proper objectives. The precision landing objective is to deploy a parachute within 10 km of the target, and the aerocapture objective is to use a single atmospheric pass instead of an orbit insertion burn, with the requirement of being within 0.1° of the desired inclination and needing less than 130 m/sec velocity increment (∆V) to achieve the final orbit. For the precision landing mission, this paper will describe the algorithm, discuss the performance for the nominal mission and describe trade studies designed to evaluate the robust-ness of the algorithm. For the aerocapture mission, only results for the nominal mission are discussed. Overview The specific objectives defined by the MSP project office for the guidance algorithms depend on the spacecraft and mission. The MSP '01 Lander must meet the parachute deployment conditions (Mach number between 1.6 and 2.3 and dynamic pressure between 400 and 1175 N/m 2) while arriving within 10 km of its target point. For the MSP '01 Orbiter, a final inclination of 92.92° ± 0.10°, an orbital periapsis altitude (above a reference sphere) higher than –150 km, and a total ∆V less than 130 m/s for circularization into a 400 km orbit are required. Abstract This paper describes the development and evaluation of a numerical roll reversal predictor-corrector guidance algorithm for the atmospheric flight portion of the Mars Surveyor Program 2001 Orbiter and Lander missions. The Lander mission utilizes direct entry and has a demanding requirement to deploy its parachute within 10 km of the target deployment point. The Orbiter mission utilizes aerocapture to achieve a precise captured orbit with a single atmospheric pass. Detailed descriptions of these predictor-corrector algorithms are given. Also, results of three and six degree-of-freedom Monte Carlo simulations which include navigation, aerodynamics , mass properties and atmospheric density uncertainties are presented.