Mars Science Laboratory: Entry, Descent, and Landing System Performance

Abstract

Abstract-In 2010, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems, by delivering the largest and most capable rover to date to the surface of Mars. To do so, MSL will fly a guided lifting entry at a lift-to-drag ratio in excess of that ever flown at Mars, deploy the largest parachute ever at Mars, and perform a novel Sky Crane maneuver. Through improved altitude capability, increased latitude coverage, and more accurate payload delivery, MSL is allowing the science community to consider the exploration of previously inaccessible regions of the planet.The MSL EDL system is a new EDL architecture based on Viking heritage technologies and designed to meet the challenges of landing increasing massive payloads on Mars. In accordance with level-1 requirements, the MSL EDL system is being designed to land an 850 kg rover to altitudes as high as 1 km above the Mars Orbiter Laser Altimeter defined areoid within 10 km of the desired landing site. Accordingly, MSL will enter the largest entry mass, fly the largest 70 degree sphere-cone aeroshell, generate the largest hypersonic lift-to-drag ratio, and deploy the largest Disk-Gap-Band supersonic parachute of any previous mission to Mars. Major EDL events include a hypersonic guided entry, supersonic parachute deploy and inflation, subsonic heatshield jettison, terminal descent sensor acquisition, powered descent initiation, sky crane terminal descent, rover touchdown detection, and descent stage flyaway. Key performance metrics, derived from level-1 requirements and tracked by the EDL design team to indicate performance capability and timeline margins, include altitude and range at parachute deploy, time on radar, and propellant use.The MSL EDL system, which will continue to develop over the next three years, will enable a notable extension in the advancement of Mars surface science by delivering more science capability than ever before to the surface of Mars. This paper describes the current MSL EDL system performance as predicted by end-to-end EDL simulations, highlights the sensitivity of this baseline performance to several key

Analysis of predictive entry guidance for a Mars lander under high model uncertainties

“…The predictive guidance algorithms need to get complete information about the current state vector of the lander (i.e., velocity and position) both at the beginning of the entry phase and at each control corrections over the path. This task is accomplished by an onboard astro-inertial navigation system being analogous to that to be used in MSL [6], which includes a star scanner for determining the lander attitude during cruise, and a strapdown inertial measurement unit equipped with three accelerometers and three laser gyroscopes. Approach navigation is performed using radiometric tracking data provided by the Deep Space Network.…”

“…Such a choice was caused by the difficulties to satisfy soft landing conditions after the entry phase, since a re-entry vehicle has to be designed with a very large ballistic coefficient s=0.5C D S m À 1 in order to slow down properly in highly rarefied Martian atmosphere with large, hardly predictable variations. Research efforts in the last decade continue to be concentrated on solving the problem of maximizing the final altitude at entry phase [4,5] in view of the planned complex unmanned Mars missions like Mars Science Laboratory (MSL) [6] as well as eventual human explorations with new EDL challenges discussed in [7,8]. At the same period, some articles have appeared [1,2,[9][10][11], which are centred on the development of more precise closed-loop entry guidance systems with a target miss less than 10 km at the parachute deployment height.…”

Atmospheric risk assessment for the Mars Science Laboratory Entry, Descent, and Landing system

“…These simulations contain vehicle models, such as mass properties and thruster models, as well as environmental interaction models such as aerodynamics and radar/terrain models [10]. Clearly, the atmosphere is another necessary model to include.…”

Coupled Fluids-Radiation Analysis of a High-Mass Mars Entry Vehicle

“…The capsules for these missions were all based on 70-degree sphere cone geometries with diameters ranging from 2.65 to 3.5 m. The highest entry velocity was achieved by the Mars Pathfinder vehicle at 7.26 km/s. The proposed Mars Science Laboratory (MSL) mission, currently scheduled to land on Mars in 2012, is the largest unmanned Mars robotic vehicle currently planned and features a 4.5 m diameter 70-degree sphere cone capsule [2]. The MSL will have an entry velocity in the range of 6.0 km/s.…”

“…In recent years, a number of studies have been performed to determine the vehicle and mission requirements that would enable the human exploration of Mars [1][2][3][4][5][6][7][8]. The vehicle geometries of these proposed high-mass Mars vehicles were based on 70-degree sphere cones, Apollo-type capsules, or a slender, mid lift-over-drag ratio (L/D) vehicle referred to as an Ellipsled.…”