Living down here on Earth it’s easy to forget that we have it pretty good, at least in terms
of our environment not doing everything it can to destroy us and everything we love.
But that’s not the case in space, and scientists have had to solve all sorts of challenges
to keep space stations, probes, and satellites functioning in such an extreme environment.
For example, they have to engineer their way around problems like temperature.
Space can be extremely cold; the background temperature of space is minus two hundred
seventy degrees celsius in the shade, just a few degrees above absolute zero.
But in direct sunlight radiation can warm a spacecraft hundreds of degrees, especially
when it’s closer to the sun.
Temperature extremes can damage or shatter delicate equipment, and depending on the mission,
engineers will have to either insulate their spacecraft from the cold or protect it from
the heat.
Sometimes they’ll have to do both!
The European Space Agency’s Rosetta mission had to chase down a comet.
To get there Rosetta had to do several planetary flybys before heading out towards the asteroid
belt.
On its ten year journey it went through wild temperature fluctuations, so to overcome this
engineers fitted Rosetta with metal slats or “louvres” that could open to let heat
radiate away or close to trap it and keep the probe warm.
Comets like the one rosetta caught leave a trail of dust in their wake, and are frequently
the cause of meteor showers we see on Earth.
Those little dust particles can also pose a threat to spacecraft because they’re traveling
at thousands of kilometers per hour.
These can have the effect of sandblasting solar arrays, harming optics, or damaging
the structure outright.
The best strategy is avoidance -- chart a course where you don’t think there’s going
to be a lot of debris, but if it’s unavoidable there’s still measures you can take.
When the Hubble telescope passes through a meteor shower, scientists will rotate it so
those big solar panels are edge-on to the incoming hazard, minimizing its surface area
like a fencer standing sideways.
But even if a spacecraft can keep itself at the right temperature and avoid physical impacts,
there’s another hazard that will always get them in the end.
Spacecraft are exposed to extreme radiation, mostly in the form of high-energy charged
particles.
These particles can come from the sun or just be zipping around the galaxy as cosmic rays.
They can also be trapped by the Earth’s magnetic field and form enormous bands of
protons and electrons called Van Allen belts.
Not only do these particles pose a threat to humans, but they can damage the electronics
of spacecraft as well.
They can cause a current to flow on the surface of the craft, or burn out chips.
They can even change the contents of memory cells, corrupting data the spacecraft’s
computers need to function.
If the computers fail or valuable data gets corrupted, the whole mission can be a bust,
so engineers have to come up with strategies to protect electronics from radiation in space,
what’s known as “space hardening.”
They can try and shield the electronics, but shielding is heavy and weight adds cost to
the launch.
Spacecraft can have redundant electronics, like three chips performing the same operation
simultaneously.
If radiation causes one to make an error, the other two can check its work and overrule
it.
This way they can just use commercial electronics, which are cheaper.
Interestingly, electronics today are more sensitive to space radiation than they were
in the 60s and 70s.
To make them more robust the chips themselves can be designed in such a way that makes them
resistant to radiation.
Designing hardened chips is difficult and expensive though, and one of the most popular
chips still in use has the processing power of a laptop from almost two decades ago.
Even with all these precautions, even the best space-born electronics will still fail
eventually.
For more epic stories of innovation that shaped our future, check out TheAgeOfAerospace.com
If you like this video don’t forget to subscribe.
Despite the challenges we have launched an absurd number of satellites up there.
Is there room for any more?
Amy covers that here.One cool thing about Rosetta’s louvres is they opened and closed
automatically.
The springs were temperature sensitive because of the metals they were made of and so they
used no power.
Thanks for watching and stay tuned to Seeker!