PARIS, Dec. 19 (UPI) -- The ExoMars Trace Gas Orbiter is preparing to dip into the Martian atmosphere and transform its orbital path. The European Space Agency's latest Mars orbiter is tasked with mapping Mars' atmosphere, but it can't begin its scientific mission until it assumes a new path -- a transformation that will take 13 months.
ExoMars TGO began orbiting Mars in late October, after a seven-month journey from Earth. Currently, the probe's highly elliptical orbit sends it as far away as 60,000 miles from the Red Planet. Twice during its four-day orbit, the Trace Gas Orbiter dips into the Martian atmosphere and comes within 155 miles of the Martian surface.
Its current orbit isn't ideal for atmospheric analysis, the probe's central scientific mission. Over the next 13 months, the ExoMars craft will continue to slow itself and transform its trajectory, trading its elongated path for a more circular orbit at an altitude of 248 miles -- a height that will allow the probe to constantly sample and observe the atmosphere.
The probe will uses friction to transform its orbital shape -- a technique called "aerobraking." Mars' outer atmosphere will slow the probe's speed while the Red Planet's gravity will slowly pull the craft into a closer orbit. The Trace Gas Orbiter will only need to use its engines a few times.
The ExoMars TGO will begin aerobraking on March 15. Its orbital transformation won't be complete until early 2018.
"This will be our first time to use aerobraking to achieve an operational orbit, so we're taking the extra time available now to ensure our plans are robust and cater for any contingencies," flight director Michel Denis said in a news release.
Once the circular orbit is achieved, scientific observations will begin.