ESA will provide live coverage here kicking off at 08:30 GMT, with the launch scheduled for 09:31 GMT.
Next stop Mars. Pic: ESA / B. Bethge
Suitably enclosed, the spacecraft were then mated with the Proton-M, as shown in this very fine snap:
Say cheese. Pic: KhSC
The trip to Mars will take seven months. Schiaparelli is scheduled to detach from the TGO on 16 October, three days before arrival. While the latter will manoeuvre into orbit at an altitude of 400km, the former will descend to the Martian surface, slowed sequentially by parachute, hydrazine thrusters, and a "crushable structure" designed to absorb the force of the final impact. ESA has a graphic of the descent sequence here.
Schiaparelli bids adios to the TGO. Pic: ESA/ D. Ducros
Aloft, meanwhile, the TGO's four instruments will help "gain a better understanding of methane and other atmospheric gases that are present in small concentrations (less than 1 per cent of the atmosphere) but nevertheless could be evidence for possible biological or geological activity". They'll also carry out surface imaging and map "shallow subsurface water ice" to a depth of one metre.
ESA is planing a second ExoMars mission in 2018, which "includes a rover that will carry a drill and a suite of instruments dedicated to exobiology and geochemistry research". ®