Rosetta’s about to attempt its dramatic comet landing

The Rosetta spacecraft’s Philae lander is attempting to land on the awkwardly named comet, 67P/Churyumov–Gerasimenko. The slightly-above 100kg probe will fall for seven hours. If everything goes according to plan, it will land on a suitable patch of the 4km-long comet.

Stephan Ulamec, the head Rosetta lander, said that “The most critical point was and still is the landing itself, the touchdown on the surface. This is where we will need some portion of luck.”

Tiny margins, massive problems

Even the slightest landing error could blow the mission. If Philae overshoots and misses the comet or approaches at a bad angle, the mission will be a miss. Thanks to the comet’s gentle gravitation pull, the touchdown will occur at “walking speed”, according to the European Space Agency.

Philae will begin its landing procedure by shooting harpoon-like anchors into the comet. The probe is also equipped with thrusters that keep the probe upright, but these may not be operational.

Ulamec notes that there is an issue with the cold gas trusting system which pegs the craft to the comet’s surface. This could be a major issue, but we’ll only know just how much of an issue it really is in a few hours.

A decade in the making

The Rosetta orbiter’s dream began in 2004 and over the years had to orbit the Earth three times, using the planet’s gravitational force, to land on the comet. In the beginning of the development, Rosetta struggled to travel when it was not in direct sunlight. To counter this, Rosetta now hibernates in darkness with only the vital functions running.

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Considering that comets are mostly ice, the Rosetta orbiter’s hibernation feature will have to work properly.

“Comets have the beauty of having preserved the ingredients with which the solar system formed,” says Jean-Pierre Bibring, Philae’s lead scientist.

“Some of the complex molecules thought to be the first building blocks for life may be preserved in 67P’s ice.”

From the moment Philae lands, it will have roughly 60 hours at full power to run experiments by using its 10 on board instruments before its batteries drain. If the lander is fortunate enough to find sunlight on the frozen world, Philae’s solar panels will recharge the craft.

Separation of the lander happened earlier today while touch down should follow about seven hours later, at 16:02 GMT (17:02 CAT). Watch the livestream here.

Social media coverage

You can follow the landing on Philae or Rosetta‘s Twitter handle or through the hashtag #CometLanding.

Philae is quite a quirky character as well. Here’s a sample of the latest tweets thus far:

.@ESA_Rosetta I will send you hundreds of postcards from #67P 🙂 #CometLanding

— Philae Lander (@Philae2014) November 12, 2014

.@ESA_Rosetta WOW! I feel like I’m floating! And #67P is closer and closer… #CometLanding — Philae Lander (@Philae2014) November 12, 2014

Finally! I’m stretching my legs after more than 10 years. Landing gear deployed! #CometLanding

— Philae Lander (@Philae2014) November 12, 2014