A European mission to look for signs of life on Mars will reach its climax on Wednesday, 19 October, when it attempts to land a probe on the planet’s surface.
The lander, called Schiaparelli, is ESA’s first attempt to touch down on Mars since the UK’s ill-fated Beagle 2 mission which was lost on Christmas Day, 2003.
Schiaparelli, also known as the Entry, descent, and landing Demonstrator Module (EDM), is named after an historic Italian Mars observer.
It separated from a companion spacecraft called the Trace Gas Orbiter (TGO) on Sunday (16th). They had travelled together on a seven-month journey across the Solar System since launch in March.
The climax of the European Space Agency’s joint mission, dubbed ExoMars 2016, comes just three weeks after it brought its highly successful Rosetta mission to a comet to an end by landing on its surface.
A visualisation in real time of Schiaparelli’s landing. Credit: ESA
On Wednesday, Schiaparelli will enter Mars’ atmosphere at a speed of nearly 21,000 km (13,000 miles) per hour. It will descend taking photos as it goes, and then land, all in the space of six minutes. Its landing site is in a region, close to the equator, called Meridiani Planum. NASA’s long-running rover Opportunity is exploring the same region.
Schiaparelli’s parachute, with a 10-metre (30ft) wide canopy, will open while it is still travelling at supersonic speeds. The probe’s front shield will then detach allowing the probe’s radar to check its altitude and speed.
This will help Schiaparelli’s Guidance, Navigation and Control system to control the three clusters of three thrusters that will act as its brakes. The thrusters will control its descent until it is about 2 metres (6ft) above the surface when they will switch off and the probe will drop to a cushioned landing.
Schiaparelli is intended as a demonstrator for the second ExoMars lander, due to launch in 2020, which will run about on the Martian surface. For a few days it will operate as a weather station on the Martian surface, including a spare wind sensor from the Beagle 2 project.
While the landing is happening, TGO will fire its main engine for 139 minutes to slow down and be captured by the Martian gravity. That will put it into an initial orbit that carries it from a distance of 96,000 km (60,000 miles) to just 300 km (186 miles) every four days.
Eventually the spacecraft will settle in a circular orbit, 400 km (250 miles) high, to begin its mission looking for evidence of current or historic life on Mars. Other probes have detected hints of methane gas in the atmosphere. Scientists want to know whether it is being produced by living organisms beneath the Martian soil, or by geological activity.
TGO will try to sniff out the lesser gases in the Martian atmosphere. One of its key goals is to follow up on hints from previous space missions and ground-based observations that found small amounts of methane in the atmosphere of Mars.
On Earth, methane is mostly produced by biological processes, but it can also be produced by geological activity. By observing when and where it appears on Mars, TGO will hopefully pin down the likely cause and determine whether there might be life on Mars.
TGO will also map hydrogen to a depth of one metre beneath the surface, to help locate undergrund water ice, plus it will act as a data relay for the ExoMars 2020 rover and NASA’s rovers.
The Russian space agency Roscosmos stepped in to launch the ExoMars missions after the European Space Agency’s original partners NASA pulled out in 2012.