Without Global Positioning Satellites, how will I know where the nearest off-license
is?
Oh, don’t worry, you can just use your A to Zed!
Hey there DNews navigators, Amy here flying you through this episode of DNews, with my
co-pilot Trace.
GPS is basically a science-created miracle.
In brief and without satisfying detail, GPS relies on network of satellites in orbit above
the Earth that can determine your exact position on the globe.
The thing is, and this is going to blow your mind, there’s more than one GPS system!
Russia’s is called GLONASS, and Europe’s is Galileo, ours is Navstar (weird); and China
and India’s regional systems (they only work there) are called Beidou and NAVIC, respectively.
Europe is building Galileo right now, and is hoping to finish in 2020, but there’s
a problem.
The clocks on board the satellites keep breaking…
Of the 18 sats currently in orbit, nine clocks are broken.
This is serious.
GPS only works with sat signals, plus mathematics, and nanosecond-precise timekeeping.
So the ESA put atomic clocks on the satellites to keep things perfectly in sync.
They even have to update them because of the rules of relativity, but you can watch other
videos for that…
The question they’re left with is, can they fix these satellites?
Or nah?
It really depends on the satellite.
I mean, we’ve repaired satellites before!
Like Hubble!
The hubble space telescope was launched in 1990, and filled the cargo bay of the space
shuttle.
After being placed in orbit, they opened the lens cover and saw…
well crap.
Blurry images.
There was a flaw in the Hubble mirror rendering it crippled!I It was a huge embarrassment
for NASA.
It took five more shuttle missions to repair the space-based scientific instrument -- fixing
the mirror, replacing and repairing some mechanical parts, and two scientific instruments.
It was repaired again in 2009.
And of course, it was worth it.
Completely.
But would have been impossible had the telescope not been designed to be repaired!
We can’t just fly up to any old sat and tinker, they don’t work that way.
Sometimes we have to get creative.
Like with the Kepler satellite.
Kepler was launched in 2009.
It’s designed to spot planets in other solar systems… which requires tracking stars for
long periods of time to try and spot planets passing in front of them.
To move a satellite in space for tracking, thrusters are out, you can’t exactly get
out and push… instead, they use what are called reaction wheels.
Reaction wheels are a kind of orientation system.
Basically, they spin super fast -- think thousands of revolutions per minute -- and the sheer
force of that spinning motion transfers energy to the spacecraft to slightly adjust its orientation.
Spacecraft typically have four wheels each offset from one another.
Three are the primary wheels and one’s a backup.
But at the end of the day, it’s hardware.
Unfortunately, after years of successful planet-hunting, the reaction wheels on Kepler broke -- meaning
it couldn’t spin and point at stars.
They now use pressure from the solar wind to hold the satellite in place, plus the remaining
two reaction wheels to keep Kepler stable!
Now it’s on to a new mission called K2!
Planet hunting, Ho!
Aside from hardware issues, satellites are running computer programs too, and sometimes
even those can cause problems!
On July 4 of 2015, NASA lost contact with the New Horizons spacecraft.
They got a message at Mission Control saying it was in “safe mode.”
It’s like your laptop, so it’s just a super basic boot-up… obviously not ideal
when you’re 10 days away from Pluto.
But unlike your laptop, the team couldn’t exactly pop up there and hold down the power
button to reboot it.
It was 3 billion miles from Earth, meaning signals took four hours to go just one way!
After a lot of frantic troubleshooting, mission scientists were able to reset the primary
computer with a set of commands, and after waiting hours to get confirmation from the
spacecraft -- they were thrilled to see it was up and running.
Pluto encounter saved!
So back to Europe’s broken GPS.
It’s not a software issue, it’s a hardware issue… short circuits -- or so they think.
Regardless, the clocks have failed.
Even though we flew up to fix Hubble, we can’t do that here.
Hubble orbits really close to the Earth, while GPS is really far away.
Impossible to reach even with a space shuttle.
So we can’t fix these.
But, luckily, there are four redundant clocks on each Galileo satellite, just in case.
So a single failure -- or even many -- won’t necessarily kill the 14 billion-dollar system,
but the breaking clocks might cause delays.
So we stop launching satellites and find the problem?
Or do we keep launching them and cross our fingers there won’t be more failures?
Administrators are thinking about this.
If the clocks keep failing, the satellites might have to be replaced sooner than their
10 to 20 year lifespan.
The system isn't even fully operational, it's set to be so in 2020.
But, by then who knows what GPS is going to look like!?
It could be like an implant in my brain.
Oh that would be awesome!
For more on GPS and how it works… literally everything you ever would want to know about
atomic clocks, relativity, and how you can use your phone to find things.
Watch this video.
Have you ever tried to live without GPS?
Seriously.
Try it.
Tell us your thoughts in the comments.
Make sure you subscribe for more DNews and thanks for watching.