EXOMARS DESCENT MODULE A MARTIAN STATIONARY SCIENTIFIC STATION ON THE LANDER

摘要

ExoMars is the first mission of the ESA Exploration Programme - Aurora. It will demonstrate flight and in-situ verification of key exploration enabling technologies to support the European ambitions for future human exploration missions, such as Entry, Descent and Landing (EDL) of a large payload (1200 Kg) on the surface of Mars, surface mobility via a Rover having several kilometres of mobility range and access to sub-surface via a Drill to acquire samples down to 2 meters. In parallel, important scientific objectives will be accomplished through a state-of-the art scientific payload, such as to establish whether life ever existed or still exists on Mars. ExoMars will search for traces of past and present life, characterize the Mars geochemistry and water distribution, improve the knowledge of the Mars environment and geophysics, and identify possible surface hazards to future human exploration missions.The mission configuration chosen by the Participating States, after a round of studies that included options for an ESA Orbiter, is the Enhanced Baseline Mission. This Enhanced ExoMars foresees the launch of a Spacecraft (SC) Composite by means of an Ariane 5 launcher lifting from Kourou (Proton-M from Baikonur as back-up) with two possible launch windows: Nov-Dec 2013 (baseline) and Jan 2016 (backup). The SC Composite is formed by a Carrier Module and a Descent Module Composite, consisting of the Descent Module (DM) housing the Rover Module with its Pasteur PayLoad (PPL). The ExoMars project is presently undergoing its Phase B2 with Thales Alenia Space-Italia (Turin site) as Industrial Prime Contractor. Additionally, the architecture of the Lander (a DM sub module) is under study in TAS-I (Thales Alenia Space-Italia), as Descent Module responsible, to operate as a stationary scientific station capable to provide basic services such as power, data handling, thermal control and communications for a set of Geophysical and Environmental instruments called the Humboldt Payload (HPL) to be developed by National Space Agencies and delivered to TAS-I by the ESA. The HPL includes instruments to perform atmospheric investigations (humidity and dust, radiation, electric and magnetic fields measurement) and surface/subsurface investigations (seismic waves, soil heat flow measurement, radio science for geodesy and ionosphere).The Descent Module will enter the atmosphere at a predetermined angle to match the heat shield performance capabilities in order to slow it down from the planetary approach velocity to a speed at which parachutes may deploy in the Martian atmosphere. Once the parachutes are deployed the protective heat shield is jettisoned. The remaining part of the Descent Module then further decelerates with the parachutes until it approaches the surface. At the right moment control rockets are fired to stabilise the Lander, for the final fall to the surface just prior to separation from the parachutes. The Lander final falls to the surface is cushioned by vented airbags which are inflated to protect the Lander when it impacts the surface. The vented airbags will deflate on impact, thereby absorbing the energy of the final descent. Once on the Martian surface, the Lander will open its walls to expose the solar cells mounted on them to the Sun light and permits the Rover to egress. After the Rover has performed its egress manoeuvres, the Mars science surface operations of the Humboldt Payload will start and will last until 180-sol (6 months) from Lander touch-down.