It was a nail-biting evening for NASA scientists, but after a tense 30 minutes of brake slamming, the MAVEN spacecraft finally arrived in orbit above the Red Planet late last night. Having spent 10 months zooming across our solar system, covering a whopping 442 million kilometers (274 million miles), MAVEN will now embark on its one Earth year mission to study changes in the Martian atmosphere.
To slip into orbit, the craft fired its six thruster engines as it approached the planet to first ensure proper orientation. As it passed over Mars’ north pole, clocking an incredible 16,000 kph (10,000 mph), the engines began a half-hour slow burn to reduce velocity so that the planet’s gravity field could capture the craft into a highly-elliptical orbit. That costly 33 minute maneuver wiped out half of MAVEN’s onboard propellant, but thankfully it was a success.
Now in capture orbit, the craft will enter a six week commissioning phase that will reduce MAVEN’s orbital period from 35 hours to just 4.5 hours for the next science collection phase. MAVEN will then spend at least one Earth year (half a Martian year) collecting atmospheric data, dipping between 150 km (93 miles) and 6,200 km (3,852 miles) from Mars’ surface.
MAVEN—Mars Atmosphere and Volatile Evolution mission—aims to understand how Mars’ atmosphere has changed over time. In particular, they hope to find out what caused the atmosphere to be gradually stripped of water and other volatile compounds such as CO2. Over the last few million years, almost 99% of the planet’s atmosphere has been swept into space by solar winds, which is probably due to the loss of its protective magnetic field. By collecting detailed measurements of the upper atmosphere using eight different instruments, scientists hope to calculate the current rate at which the atmosphere is escaping. From this, researchers should be able to backtrack and determine the history of habitability on the planet.
The craft will also have a rare and exciting opportunity to catch a glimpse of comet Sliding Spring that will whizz by Mars next month. The risk of damage to the craft is minimal, but the comet will more than double the amount of hydrogen present in the atmosphere for a couple of days which will increase drag.
MAVEN won’t be lonely on its Red Planet mission as it is joining three other crafts already in orbit, alongside several land-based robots. A fourth spacecraft—India’s Mangalyaan—is also due to join the crowd in just two days. Mangalyaan is India’s first satellite to Mars and while it has different objectives, it will also collect atmospheric data that will be shared with MAVEN observations.
“MAVEN will complement NASA’s other Martian robotic explorers—and those of our partners around the globe—to answer some fundamental questions about Mars and life beyond Earth," NASA astronaut John Grunsfeld said in a news release.