Image caption The Trace Gas Orbiter is about to undergo some mechanical, thermal and vacuum tests

The satellite Europe will be sending to Mars early next year is about to undergo its final test programme.

The Trace Gas Orbiter (TGO) will study the planet's atmosphere, and drop a demonstration lander on to the surface to gain knowhow for a rover mission touchdown in 2019.

Engineers at Thales Alenia Space (TAS) in Cannes, France, have led the construction of the spacecraft.

Russia, Europe's partner on the project, will handle the launch.

This will be done on a Proton rocket from Baikonur in Kazakhstan in January. The transit to Mars will take about nine months.

The TAS engineers are in the process of joining the descent module, known as Schiaparelli, to the TGO.

Vincenzo Giorgio, the company's director of science programmes, explained: "They'll then go for shaking - some mechanical tests - and then into the thermal-vacuum chamber. After that, there will be some additional end-to-end testing, before we ship out this summer."

TAS originally intended to do some of the final check-out at its site in Turin, Italy, but conducting all the work in Cannes will shave a couple of weeks off the timeline.

The European Space Agency's (Esa) TGO will examine the Martian atmosphere in detail, characterising the gases of low concentration. These include methane, which could hint at biological activity on the planet.

Image caption The 600kg Schiaparelli demonstration module will prove key landing technologies

The satellite's first task, however, will be to deliver Schiaparelli. It will release the 600kg module three days before arrival, putting the demonstrator on a ballistic path towards the flat equatorial plain of Meridiani.

Entering the atmosphere at 5.8km/s, Schiaparelli will use parachutes and thrusters to slow its descent before dumping down on to the ground at just 1m/s. It will have a crushable floor to soften the impact.

Although Schiaparelli will do some weather observations once on the ground, its main purpose is to prove key technologies required to land the ExoMars rover three years later.

Elements of the guidance, navigation and control system, the radar doppler altimeter and the inertial measurement units will all be used again in the rover's landing mechanism.

Most of this mechanism is being built by the Russian Lavochkin company. The rover itself is being assembled by Airbus Defence and Space in the UK.

The TGO and the rover are considered a joint programme by Esa. The Russian space agency came into the project when the Americans scaled back their involvement.

The US still has technical contributions to both the TGO and the rover. A major US role is in supplying the Electra communications package on the orbiter. This will allow surface robots to relay their data to Earth.

Image caption The Trace Gas Orbiter will return its information to Earth via a large high-gain antenna

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos