Mars Exploration Entry, Descent, and Landing Challenges

The United States has successfully landed five robotic systems on the surface of Mars. These systems all had landed mass below 0.6 metric tons (t), had landed footprints on the order of hundreds of km and landed at sites below-1.4 km MOLA elevation due the need to perform entry, descent and landing operations in an environment with sufficient atmospheric density. At present, robotic exploration systems engineers are struggling with the challenges of increasing landed mass capability to 0.8 t while improving landed accuracy to tens of km and landing at a site as high as +2 km MOLA elevation for the Mars Science Laboratory project. Meanwhile, current plans for human exploration of Mars call for the landing of 40-80 t surface elements at scientifically interesting locations within close proximity (tens of m) of pre-positioned robotic assets. This paper summarizes past successful entry, descent and landing systems and approaches being developed by the robotic Mars exploration program to increased landed performance (mass, accuracy and surface elevation). In addition, the entry, descent and landing sequence for a human exploration system will be reviewed, highlighting the technology and systems advances required. Nomenclature A = aerodynamic reference area, m2 CD = aerodynamic drag coefficient CD = aerodynamic lift coefficient g = 1 Earth deceleration unit, 9.806 m/s2 Isp = specific impulse, s L/D = lift-to-drag ratio m = mass, kg α = angle of attack, deg β = ballistic coefficient, kg/m2 ΔV = propulsive velocity change, m/s τ = atmospheric opacity I