Challenge on the Red Planet: ESA's ExoMars Trace Gas Orbiter to Skim Alien Atmosphere on Mars
Mission controllers from the European Space Agency are now preparing ExoMars Trace Gas Orbiter (TGO) for its mission finale: dipping into the Red Planet's atmosphere to reach its final orbit.
The ExoMars Trace Gas Orbiter was designed by ESA, while Roscosmos provided its launch vehicle, a Proton rocket. It is on a multilayer mission to explore the minute amounts of methane and other gases found in the Martian atmosphere. All of which would be used as evidence to investigate any possibility of biological or geological activity in the planet.
According to a press release by ESA, the orbiter fired its main engine on 19 October to brake sufficiently for capture by the planet's gravity, after its long arduous journey from the Earth. It entered a highly elliptical orbit where its altitude varies between about 250 kilometer and 98 000 kilometer, with each circuit taking about four Earth days.
In order to accomplish its science goals and role as a data relay for surface rovers, the ExoMars Trace Gas Orbiter must lower itself into a near-circular orbit at 400 kilometer altitude, with each orbit taking about two hours.
To do this, ESA mission controllers will use "aerobreaking," an innovative technique in which the craft will be tasked to skim the wispy tops of the Martian atmosphere, producing a little drag that will slow TGO and steadily lower it onto the required two-hour, 400-kilometer orbit, Space Daily reported.
"The amount of drag is very tiny," spacecraft operations manager Peter Schmitz stated, "but after about 13 months this will be enough to reach the planned 400 kilometer altitude while firing the engine only a few times, saving on fuel."
In the aerobraking process, the ESA's mission control team headquartered in Darmstadt, Germany, will closely monitor the craft during each orbit to make sure it does not get damaged from to too much friction heating or pressure.
The aerobraking campaign is scheduled on 15 March 2017, when Mars is over 300 million kilometer from Earth, and will continue until early 2018, Mars Daily wrote.
Prior to the ExoMars mission, ESA's previous aerobraking experience was using the Venus Express launched in 2005. However, that was done only as a demonstration at the end of the mission. NASA, on the other hand, also performed the aerobraking technique in taking their Mars Reconnaissance Orbiter and other spacecraft into low orbits at Mars.