China’s space agency has a penchant for secrecy around its missions. It has shown more openness in the past year, providing a live video on state media of its Chang’e-4 mission’s launch to the moon. Should it announce a more precise arrival time, we will provide it here.
What will the spacecraft do on Wednesday?
Tianwen-1 launched from China last July, taking advantage of a period when Mars and Earth were closest to each other during their journeys around the sun. This allows a relatively short transit between the two worlds.
To catch up with Mars, the spacecraft has fired its engines on several occasions, correcting its course so it can approach the red planet at the correct angle. The most recent engine firing occurred on Feb. 5, and the probe sent back pictures of the red planet from a distance of about 1.3 million miles.
On Wednesday, the engine will light up again, expending much of the spacecraft’s remaining fuel in a braking maneuver. That should slow it considerably, and allow the probe to be captured by Martian gravity. There it will circle at a safe distance, joining the other cast of robotic explorers in Martian orbit and preparing for that later surface landing attempt.
Could anything go wrong?
The history of spaceflight is littered with failed voyages to Mars, including a Chinese mission in 2011 that never got out of Earth’s orbit after the Russian rocket it was traveling on failed. And a few spacecraft have stumbled during this final step of preparing to enter Martian orbit.
For instance, in 1999, NASA’s Mars Climate Orbiter suffered a navigation error — English units were not converted to metric — and the spacecraft burned in the Martian atmosphere. In 1992, NASA lost contact with its Mars Observer spacecraft days before it was to arrive at Mars, perhaps because of a fuel line rupture. After a Soviet mission in 1974, Mars 4, failed to fire its retro rockets, the spacecraft sailed away from Mars.
Still, the challenge of orbiting Mars is nothing compared with landing there.
When will China land on Mars?
The orbiter carries a lander and a rover which will make the difficult transit to the surface. China says it will attempt to land on Mars in May, but it has not specified a date.
Its destination is Utopia Planitia, a large basin in the northern hemisphere that most likely was once impacted by a meteor, and which was visited by NASA’s Viking 2 lander in 1976. One goal of the Tianwen-1 mission is to better understand the distribution of ice in this region, which future human colonists on Mars could use to sustain themselves.
Landing on the red planet is perilous. Spacecraft descend at a high speed and the thin atmosphere does little to help slow the trip to the ground. Air friction still generates extreme heat that must be absorbed or dissipated. A number of Soviet, NASA and European missions have crashed. Only NASA has landed intact more than once.
The Chinese spacecraft will spend months orbiting Mars to check systems and pick a landing spot that will not be too treacherous.
Should it land in one piece, the rover will need a name. After nominations from people in China, a panel of experts selected 10 semifinalists. Among…
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