Getting to space is hard. Successfully landing a rover/lander on Mars? If your space agency isn’t named NASA, it’s been impossible. But a joint mission by the European Space Agency and Roscosmos is hoping to change that next week.
On March 14, the ExoMars mission began its seven-month journey. ExoMars is a two-part mission. This first part is made up of two components – the Trace Gas Orbiter and a test lander called Schiaparelli.
On October 16 (three days before ExoMars reaches Mars), Schiaparelli will break away from the orbiter. 15 minutes after separation, the test lander will enter hibernation as it cruises towards its October 19 meeting with the red planet. Six hours before Schiaparelli reaches Mars’ atmosphere, it will exit hibernation to warm up critical systems onboard. Just one hour before atmospheric entry, it will exit hibernation for the last time and begin executing the commands uploaded by the ExoMars team last week.
Schiaparelli will slam into Mars’ thin atmosphere at an altitude of about 121 kilometers and traveling at nearly 21,000 kilometers. The heat shield will bear the brunt of the entry. With the test lander at an altitude of 11 kilometers, a supersonic parachute will deploy. 40 seconds later, the front shield of the aeroshell will be released. The supersonic parachute will slow the Schiaparelli from a breakneck 1,700 km/h to a much more manageable 250 km/h.
At just 1.2 kilometers above Meridiani Planum, the back half of the aeroshell along with the supersonic parachute will be jettisoned. One second later, nine hydrazine-powered thrusters will fire. A radar system onboard Schiaparelli will constantly ping the surface to measure the height. The thrusters will slow the lander as it approaches the surface. At two meters, the lander will hover briefly before the engines cut out and it falls to the surface.
Two meters might seem high, but the test lander is equipped with a “crushable structure” on its underside according to the European Space Agency. Touchdown speed will be a few meters per second.
Schiaparelli will do all of this on its own. The team back on Earth won’t be able to help the lander once entry begins. It will take nearly ten minutes for signals to reach Earth from Mars. The landing sequence won’t take longer than six. Schiaparelli will already be on the surface of Mars by the time officials know it’s entering the planet’s atmosphere.
Schiaparelli is the test run for the ExoMars 2020 surface platform. Next week’s landing will demonstrate the landing technology that will be used in a few years from now. If something goes wrong, the ExoMars team can study the problem and fix it. Of course, the team wants next week’s landing to go without a hitch. But problems aren’t failures. If something goes wrong, the engineers want it to happen next week so they can address it before the ‘real’ lander heads to Mars in 2020.
The ESA will be live streaming an event next week. Confirmations for orbital insertion of the Trace Gas Orbiter and Schiaparelli’s landing are expected during it. I’ll update this post once we have a specific link. For now, keep ESA’s official website bookmarked.
The Trace Gas Orbiter (TGO)
While Schiaparelli takes most of the headlines, the second component of the mission is just as important.
The Trace Gas Orbiter will be inserted into a highly elliptical orbit and map the gases in Mars’ atmosphere. Specifically, methane. But it’ll also monitor for other trace gases.
Understanding where Mars’ methane is coming from and the concentrations of it within the planet’s atmosphere are TGO’s main goal.
TGO’s initial elliptical orbit will take it from 300 kilometers above Mars’ surface to 96,000 kilometers away. In January 2017, the spacecraft will begin a process to make its orbit more circular and drop it to a 400-kilometer orbit. ESA will use aerobraking to bring its orbit lower. TGO’s solar arrays will generate drag as the spacecraft flies through the red planet’s atmosphere at high altitudes. This slows the spacecraft and lowers its orbit. Aerobraking takes longer, but the advantage is it doesn’t use much fuel.
TGO will also act as a relay satellite and will assist in communications with NASA Curiosity and Opportunity rovers and future lander/rovers.
TGO’s mission will conduct science observations and assist with communications until late 2022.