Europe and Russia will send a test lander Sunday on a one-way trip to the Martian surface, a key step in their joint ExoMars project to search for life on the Red Planet.
Some facts about the mission:
What's in a name?
ExoMars gets its name from "exobiology" -- the science of analysing the odds and likely nature of life on other planets.
Schiaparelli, the lander, was named after a 19th century Italian astronomer who had observed lines on Mars through a telescope which he called "canali".
This was mistranslated into English as canal (instead of channel), which cause many to imagine vast irrigation networks built by intelligent creatures.
Better telescopes in the 20th century killed that legend.
The ExoMars Trace Gas Orbiter (TGO) spacecraft, which will analyse our neighbour's atmosphere, measures 3.5 metres by two metres by two metres (11.5 feet by 6.5 feet by 6.5 feet).
It has solar wings spanning 17.5 metres, tip to tip.
With the Schiaparelli lander on board, it travelled 496 million kilometres (308 million miles) to get to Mars.
On Sunday, it will release Schiaparelli from a distance of a million kilometres.
The paddling pool-sized lander, 1.6 metres wide, will test entry and landing gear for a subsequent rover to be launched in 2020.
Scientists believe Mars once hosted liquid water -- a key ingredient for life as we know it.
While the Martian surface is too dry, cold and radiation-blasted to sustain life today, this may have been a different story 3.5 billion years ago when the Red Planet's climate was warmer and wetter.
Science has long abandoned the hunt for little green men, though.
Life, if any exists, is likely underground -- away from harmful ultraviolet and cosmic rays -- and in the form of single-celled microbes.
Primitive or not, it would be the first time humans ever observe life on a planet other than Earth.
The mission will also seek to learn more about geological process on Mars, and about the sand storms that change the face of the planet with their seasonal violence.
TGO will taste Martian gases, looking specifically for methane.
Methane is important because it may be a portender of life -- on Earth it is mostly produced by biological processes.
Previous missions had already picked up traces of methane in Mars' atmosphere, but the TGO has much more sophisticated tools which scientists hope to tell whether it is biological or geological in origin.
Methane can, theoretically, also be created by underground volcanoes.
The rover will drill into Mars to look for evidence of buried, extinct life, or even live microbic activity.
While diplomatic ties between Europe and Russia may be under strain, they collaborate closely on ExoMars -- a shared project of Roscosmos and the European Space Agency (ESA).
Europe has budgeted 1.3 billion euros ($1.4 billion) for the mission
America's NASA, which was due to contribute $1.4 billion, pulled out due to budget cuts in 2012, pushing Europe to turn to Russia.
Moscow agreed to provide launcher rockets in exchange for space for science instruments onboard the craft.
The lander, Schiaparelli, is European, and the rover will be too. The platform housing the rover and its science lab will be Russian.
"We need to demonstrate our ability to do things on our own," ESA senior scientist Mark McCaughrean told AFP of the European quest.
"Its partly about proving that Europe has the capability and the will and the power to pull these projects together."...