The ExoMars Entry, Descent and Landing Demonstrator Module (EDM)

Entry, Descent and Landing on Mars, the European Perspective

  The Orbiter and the Entry, Descent and Landing Demonstrator Module in cruise configuration. Credit:ESA  

One of the core scientific goals of any mission to Mars is the search for evidence of life. The best approach is to investigate the surface where the evidence may lie.

The key element for accessing the surface of Mars and one of the greatest challenges in space exploration is the successful execution of the entry, descent and landing sequence on the surface of the planet.

This is one of the reasons why since the late 1960s there have been so many missions attempting to land on the surface of Mars, some being successful, many others ill-fated.

The EDM - a technology demonstration vehicle carried by the ExoMars Trace Gas Orbiter - will be launched in 2016 to demonstrate the capability of the European industry to perform a controlled landing on the surface of Mars. The preparation for this mission enhances Europe’s expertise and enables the testing of key technologies which could be used in subsequent missions to Mars.

Although designed to demonstrate entry, descent and landing technologies, the EDM also offers limited, but useful, science capabilities. The EDM will deliver a science package that will operate on the surface of Mars for a short duration after landing, planned to last approximately 2-8 days.

 

Arriving at Mars

The EDM will start its journey to Mars in January 2016 attached to the Trace Gas Orbiter. They will be launched on a Proton rocket and will arrive approximately 9 months later at Mars.

Coast

  • Three days before reaching the atmosphere of Mars, the EDM will separate from the Orbiter.

  • The module will then coast to Mars during which phase it will remain in hibernation mode in order to reduce its power consumption.

  • The EDM will be activated a few hours before entering the atmosphere of Mars at a velocity of approximately 5.8 km/s.


Entry

The ExoMars Entry, Descent and Landing Demonstrator Module in the 'entry phase'.
Credit: ESA

  • The EDM enters the atmosphere of Mars at an altitude of 120 km.

  • The heat shield will protect the EDM from the severe heat flux and deceleration from Mach 35 to Mach 5 (Mach 5 is motion 5 times greater than the speed of sound. Rockets and the space shuttle reach this speed as they go into orbit).


Descent 

The ExoMars Entry, Descent and Landing Demonstrator Module in the 'descent phase'.
Credit: ESA

  • As soon as the EDM has slowed down to Mach 2 (for example, the speed of a military fighter aircraft), the parachute will be deployed to further decelerate to subsonic speed (velocity less than Mach 1. This is the speed of most commercial airplanes).

  • The module will first release the front heat shield and then the rear heat shield will also be jettisoned.

  • The EDM will activate its Doppler radar altimeter and velocimeter to locate its position with respect to the Martian surface.


Landing 

The ExoMars Entry, Descent and Landing Demonstrator Module in the 'landing phase'.
Credit: ESA

  • At the optimum distance from the ground, the liquid propulsion system will be activated to reduce the speed to close to zero and to allow a controlled landing on the surface of Mars.

  • The primary landing site has been identified: it is a plain known as Meridiani Planum. This area interests scientists because it contains an ancient layer of hematite, an iron oxide that, on Earth, almost always forms in an environment containing liquid water.

A communication link between the EDM and the Orbiter will facilitate the real-time transmission of the most important data measured by the EDM. The complete set of data acquired will be transmitted to the Orbiter within 8 sols after the landing (a solar day on Mars, or sol, is 24 hours and 39 minutes). The EDM mission then comes to an end and the Orbiter sweeps through the atmosphere to reach its final science orbit.

  

Quick Facts
The EDM spacecraft will hit the atmosphere of Mars at 21,000 km per hour.
The parachute is deployed when the EDM is moving more than twice the speed of sound.
At landing, the velocity will be less than 15 km per hour.
 
The deceleration will complete in less than 8 minutes over a distance of approximately 700 km.
The EDM will arrive at Mars during the global dust storm season, which means that it may encounter a highly dust-loaded atmosphere.
The heat shield surface temperature during entry reaches approximately 1500oC.
The EDM will be designed to land on a terrain with rocks as high as 40 cm and slopes as steep as 12.5o.

 

The ExoMars EDM Design

 

ExoMars EDM exploded view. Credit: TAS-I

The EDM is building on a heritage of designs that have been evaluated and tested by ESA during earlier ExoMars studies. The spacecraft accommodates a series of sensors that will monitor the behaviour of all key technologies during the mission. These technologies include a special material for thermal protection, a parachute system, a radar Doppler altimeter system, and a braking system controlled by liquid propulsion. The data will be sent back to Earth for post-flight reconstruction in support of future European missions to Mars.

The main characteristics of the EDM are provided in the table below:

 

Main technical characteristics of the ExoMars
Entry, Descent and Landing Demonstrator Module
Diameter 2400 mm
Mass 600 kg
Heat shield material Norcoat Liege
Structure Aluminium sandwich with Carbon Fiber Reinforced Polymer skins
Parachute Disk-Gap-Band canopy, 12 m diameter
Propulsion 3 clusters of 3 hydrazine engines (400 N each), operated in pulse-modulation
Power Primary batteries
Communications UHF link with the ExoMars Orbiter (with 2 antennas)

 

The design activities are performed by European industry, led by Thales Alenia Space – Italy under the close supervision of ESA.

 

For further information, please contact:
Giacinto Gianfiglio, ExoMars System Engineering Manager
Email: giacinto.gianfiglioesa.int


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Last Update: 03 Apr 2013