The European Space Agency (ESA) reveals that its ExoMars mission team is prepping the spacecraft for an entry into Mars’ atmosphere and into its final orbit from where it will be studying tiny amounts of methane and other gases to determine their source and evidence for possible biological activity on the Red Planet.
Currently ExoMars is a highly elliptical orbit with an altitude varying between about 250 km and 98,000 km; however, for its final orbit the ExoMars has to be in a near-circular orbit at just 400 km altitude and for that purpose the spacecraft needs to be slowed down through ‘aerobraking’ commanding the craft to skim the wispy top of the atmosphere for the faint drag to steadily pull it down.
During aerobraking, the team at ESA’s mission control in Darmstadt, Germany, will be carefully monitoring the craft during each orbit to ensure it is not exposed to too much friction heating or pressure. The aerobraking campaign is set to begin on 15 March, when Mars will be just over 300 million km from Earth, and will run until early 2018.
Currently ExoMars is being prepped for the final orbit. As part of the preparation on January 19 the mission team will adjust the angle of the orbit with respect to the Mars equator to 74º so that science observations can cover most of the planet. Subsequent to that on February 3 and 9 the spacecraft’s high point will be reduced leaving it in a 200 x 33 475 km orbit.
Aerobraking proper will begin on 15 March with a series of seven thruster firings, about one every three days, that will steadily lower the craft’s altitude at closest approach – from 200 km to about 114 km. Subsequent to this Mars’ atmosphere will start doing its work says ESA pulling the spacecraft down. In early the aerobraking will end thereby placing the spacecraft in a circular 400 km orbit.
No date has been set, but science observations can begin once the final orbit is achieved. In addition, the path will provide two to three overflights of each rover every day to relay signals.