On Wednesday, April 27th, SpaceX announced that they plan to launch a Mars mission in
2018.
Now that makes a lot of sense: May 2018 is the next good time to launch spaceships to
Mars, in terms of the way the Red Planet is positioned relative to Earth.
But, before then, SpaceX has a lot of work to do, because they haven’t finished developing
the rocket that would launch the spaceship -- or the spaceship itself.
Elon Musk founded SpaceX partially because he wanted to colonize Mars, so we’ve known
about the company’s plans for a while.
But until now, we didn’t know when they were going to launch that first mission.
Turns out, it’s very soon.
SpaceX plans to get to Mars using its Falcon Heavy rocket, which would propel a Red Dragon
capsule.
The Falcon Heavy is basically a bigger, heavier version of the Falcon 9 rockets that SpaceX
uses now. So, it’ll be able to carry more stuff, and generate enough thrust to get that
stuff to Mars.
Except, the Falcon Heavy hasn’t been tested yet, and it won’t be until at least the
fall of this year.
And even though it’ll be plenty challenging, making sure the Falcon Heavy is ready to launch
a spacecraft to Mars is the easy part.
/Landing/ the Red Dragon capsule on Mars will be much harder.
Essentially, they want to use rockets to slow it to a gentle touchdown from a speed faster
than sound -- a technique called supersonic retropropulsion.
See, Red Dragon is really just a different name for Dragon 2, the capsule SpaceX plans
to use to ferry crew members to the International Space Station.
And Dragon 2 already needs these rockets for its abort system -- they make the capsule
maneuverable enough to find a safe place to land.
Which means that Red Dragon will already have its propulsion system built-in.
Plus, since Mars’s atmosphere is much thinner than Earth’s, parachutes wouldn’t be able
to slow the capsule down to a safe landing speed.
So rockets it is.
The idea might sound familiar, because that’s how the Falcon 9 Reusable rockets slow down
for their landings here on Earth.
But it’ll be hard to test the way supersonic retropropulsion would work in Mars’s thin
atmosphere.
SpaceX is researching it though -- for example, they’ve launched Falcon 9 rockets up to
parts of Earth’s upper atmosphere that are about as thin as the atmosphere on Mars.
That gives them more information on how rockets perform in Mars-like conditions in general
-- which they can use while planning Dragon tests and missions.
But, still, they have a lot of work to do in the next two years.
We don’t have too many details on the upcoming mission -- Musk has said that he plans to
reveal more during the International Astronautical Conference at the end of September.
But no matter what those plans are, a successful Mars landing would be a huge deal, and the
first time a private company has ever landed a spacecraft on another world.
Speaking of other worlds:
Earlier this week, an international team of astronomers announced that they’d discovered
three new potentially-habitable exoplanets only 40 light-years from Earth!
The researchers described the planets -- and how they found them -- in a paper published
in the journal Nature.
These three planets are probably Earth-like, meaning they’re the right size to be made
of rock.
They’re also within the so-called Goldilocks Zone -- close enough to their parent star
to be warm enough for life, but not so close that life would burn to death.
The two inner planets do receive a lot more radiation than Earth does, so the outermost
planet would be the best spot for potential life.
But, the /parent/ star is part of what makes this discovery so exciting -- it’s called
Trappist-1, and it’s a type of star known as an ultracool dwarf.
Trappist-1 is a dim, cool red star that’s barely larger than Jupiter.
And even though it’s relatively nearby, you’d have a hard time finding it in the
night sky, even with a really powerful amateur telescope.
As stars go, ultracool dwarfs are pretty common.
But this is the first time we’ve ever found exoplanets around one of them.
And the star’s dimness is a huge advantage when it comes to studying these exoplanets.
See, astronomers can study an exoplanet’s atmosphere by monitoring how the atmosphere
slightly affects the light from the star before it reaches us.
Most stars are so bright that it’s hard to see this tiny effect at all, but Trappist-1
is dim enough for our telescopes to detect it.
So, the astronomers are using the Hubble and Spitzer space telescopes to look for water
and methane in the planets’ atmospheres -- both of which could be signs of life.
And the team plans to use the James Webb space telescope, once it launches in 2018, to search
their atmospheres for ozone. This would be strong evidence -- though not definite proof
-- of some kind of biological production of oxygen, which then forms the ozone.
For now, all we know is that these planets could potentially support life. But hopefully
soon, we’ll have evidence to predict if they /do/.
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