5 Things You Need to Know About Rosetta, the Comet Chaser — The Countdown #40

On January 20th,
the Rosetta spacecraft came to life after a two-and-a-half year nap. Prepare to be amazed by what it does next! Rosetta will be the first spacecraft
to orbit a comet, and then hitch a ride around the sun. Here are 5 things you need to know
about this landmark mission. I’m Sophie and welcome to The Countdown. In 2004, the European Space Agency
launched Rosetta. At first, the spacecraft stayed
relatively close to the sun, flying by Earth, Mars
and even two asteroids. This helped Rosetta pick up energy
and align itself with Comet 67P/Churyumov–Gerasimenko. Reaching the comet, however,
meant traveling out past Jupiter, 800 million kilometers away
from the heat of the sun. To conserve energy
during this leg of the voyage, Rosetta entered
a state of hibernation in June 2011. By January of this year, it had returned
close enough to use its solar panels. Now that it could power up,
Rosetta was ready to wake up. On the morning of January 20,
Rosetta’s internal alarm clock went off. It fired its thrusters
to slow its rotation and orient its solar panels
towards the sun. Then it looked at the surrounding stars
to check its position before rotating towards Earth
and pointing its antenna at us. Finally, it fired off a signal
saying it was awake. The signal reached Earth loud and clear. You can see it in this picture
where it looks like a green spike. Now Rosetta was ready
to chase down its target. Why do we want to visit
Comet 67P/Churyumov–Gerasimenko? Well, this comet
is in just the right place. It’s still out in the cold depths
of the solar system but on its way towards the heat of the sun. As it warms up and its ice melts, the comet will spew dust and gas
into space, creating tails and Rosetta will track
this transformation as it occurs. Comets give us a glimpse
of the solar system’s youth and may have helped seed Earth
with water and organic molecules. An up-close-and-personal look can help us
learn much more about these objects. Because it’s still millions of kilometers
from its destination, Rosetta won’t enter into orbit
until August. As the craft circles, it will map
the surface of the comet in detail. Previous missions,
such as Giotto and Stardust, have flown near comets. The closest we got was the Deep Impact
space probe in 2005. But Deep Impact just shot
a hunk of metal at its comet, gathered samples and then went on its way. Rosetta will stay in orbit
for an entire year, so it will be able to track how the comet
changes as it moves closer to the sun. Rosetta will do more than just orbit. In November, it will release
its Philae lander onto the surface. Three spider-like legs will help
Philae hit the ground safely and maintain an upright position. Because the gravity of the comet
is relatively weak, Philae will anchor itself by sticking
a harpoon in the ground. The lander and its suite of instruments will give us an even better look
at the nucleus of Comet 67P. I’m Sophie Bushwick,
and that’s your Countdown. For more episodes of our show
and other spacey stuff, visit the Spacelab Channel on YouTube or follow us on Twitter @sa_spacelab And if you’ve got any topics
you’d like to see in the future, let us know in the comments.