Mars Exploration Entry, Descent, and Landing Challenges

On the use of a range trigger for the Mars Science Laboratory Entry, Descent, and Landing

“…This is because at Mars, due to the planet's thin atmosphere, only entry systems with ballistic coefficients below about 50 kg/m 2 have the ability to deliver payloads to subsonic terminal velocities [1]. For MSL, a blunt aeroshell, with a ballistic coefficient of approximately 140 kg/m 2 , is first used to slow the vehicle from hypersonic entry velocities as high as 6 km/s down to low super-sonic speeds, near 400 m/s.…”

“…The Viking parachute system was qualified to deploy between Mach 1.4 and 2.1, and a dynamic pressure between 250 and 700 P a [1]. However, Mach 2.1 is not a hard limit for successfully operating DBG parachutes at Mars and there is very little flight test data above Mach 2.1 with which to quantify the amount of increased EDL system risk.…”

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

“…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.…”

Multiple Model Adaptive Rank Estimation for Integrated Navigation During Mars Entry

“…There are many key scientific goals for Mars explorations in order to deepen the understanding of the solar system formation process and the origin of life, such as the search for water and characterisation of aqueous processes on Mars, the study of mineralogy and weathering of the Martian surface, and the search for preserved biosignatures in Martian rocks (Burkhart et al, 2005;Li et al, 2014). However, most of the preselected target sites for the key scientific goals are located at high elevations on the surface of Mars at close proximity to scientifically interesting terrain (Braun and Manning, 2007). If these sites are surrounded by hazards, the lander needs to be precisely delivered from the Mars entry point (defined as a radius of 3,522 km from the centre of Mars, and an altitude of 125 km over the surface) to the preselected target site with a 100 m level through the general Mars Entry, Descent, and Landing (EDL) phase of the mission.…”

“…So the Mars entry phase is the most important and dangerous period during the EDL phase. In order to address the first two significant sources of error, Mars entry navigation technologies play an important role during the whole of a precise landing mission (Li et al, 2014;Braun and Manning, 2007). However, there are three prerequisites affecting Mars entry navigation accuracy: firstly, an accurate Mars entry dynamic model; secondly, sufficient measurement data from the high precision sensors and thirdly, robust state estimation methods.…”