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Sealing Schiaparelli

Sealing Schiaparelli

12 February 2016

The finishing touches are being made to the protective heat shield of Schiaparelli before it is joined to the Trace Gas Orbiter.

A team of specialists from Airbus Defence and Space (Aquitaine), who arrived in Baikonur last week, have been busy this week placing and sealing the last of the tiles on Schiaparelli's heat shield and rear cover.

Placing a tile on Schiaparelli. (See full sequence below.) Credit: ESA - B. Bethge

In October this year, as it plummets through the Martian atmosphere towards the surface, Schiaparelli – the ExoMars 2016 entry, descent and landing demonstrator module – will experience very high temperatures, possibly as high as 1850°C.

For most of the descent, a front heat shield and a rear cover will protect the module.

The front shield, which has a diameter of 2.4 m and weighs 80 kg, is a carbon sandwich structure covered with 90 insulating tiles. These tiles are made of Norcoat Liège, a thermal ablative material composed of resin and cork.

The rear cover, which contains the parachute that is deployed during the descent and some engineering sensors (in particular, COMARS+) to measure aerothermal parameters, is composed of 93 tiles (in 12 different shapes), attached to a carbon sandwich structure.

The rear cover tiles and the complete front shield were produced by Airbus Defence and Space and delivered to the prime contractor, Thales Alenia Space, in July 2014. To facilitate testing and integration some parts of the shield and cover remained free of tiles at that time.

This week, as the final launch preparation activities for Schiaparelli draw to a close, it was time to place most of the remaining tiles and bond them into position. The final three tiles will be placed after the installation of Schiaparelli on top of the Trace Gas Orbiter.

1: Cleaning & decontamination of the tiles. 2: Preparing, cleaning & decontaminating Schiaparelli's structure. 3: Putting the bonding agent on a tile.
4: Spreading the bonding agent on a tile with a custom-made tool. 5: Placing a tile on Schiaparelli's structure. 6: Adjusting a tile for a perfect fit.
7: Applying calibrated pressure to a tile. 8: Putting a tile under vacuum 9: A tile after installation of a vacuum bag.

Pictures 1,2,3,5,6,7,9 Credit: ESA-B. Bethge; Pictures 4,8 Credit: ESA-O. Bayle

This tile placement activity was performed by highly trained specialists, who needed to operate flawlessly while following a very tight schedule. Bonding the tiles is carried out by following a very accurate procedure in which the mass of the bonding agent is controlled with a precision of better than 1 g and the position of each tile is within less than 1 mm of where it must be.

As Schiaparelli has been fuelled, extra safety precautions have to be taken and the specialists carrying out the difficult tasks of placing, bonding and curing the tiles have to wear special protective suits.

This was the last task to be carried out on Schiaparelli before it is united with the Trace Gas Orbiter to form what is known as the Spacecraft Composite.

Last Update: 1 September 2019