If you look up on a clear night, you might just see one.
We know they're up there cruising around our planet, listening, watching, gathering information.
These man-made systems, these satellites, make our lives better.
We use satellites basically all over the place now.
The GPS system is based on satellites.
The ability to figure out where you are on the map on your cell phone is based on satellites.
They're used in most of our communications in one form or another.
Many of your telephone calls get routed through a satellite.
Almost all of your television at some point passes through a satellite.
We use them to predict the weather, to figure out where hurricanes and figure out if its
going to be hot or cold tomorrow.
And we use them for science as well.
Satellites are also critical to the defense and security of our country.
Satellites are very important for military forces, especially for the Navy and Marine
Corps, because we operate in such remote parts of the Earth.
Satellites in orbit around the earth provide the best vantage point to provide global communications,
sensors on orbit to monitor shipping and also to monitor weather and oceanographic conditions,
and also provide global positioning system navigation and precise timing.
But satellites have their limitations.
If they break down in orbit they can't be fixed.
We build them, we launch them, and we can never too close to them.
Satellite servicing would help the defense capability because right now satellites are
the only components that I can think of that the U.S. fields that is never serviced, never
touched, never even close-inspected.
But why is that?
Why can astronauts go on space walks to fix the Hubble Space Telescope but not other satellites.
Well, Hubble is only about 350 miles above the surface of the Earth and geosynchronous
satellites are much higher - over 20,000 miles higher - where the protective magnetic field
is nonexistent
Every time it goes from light to dark it's very extreme temperature variations because
you’re outside the atmosphere and you're in this vacuum of space.
Extra radiation because of no protection from the atmosphere and there's always the danger
of some type of micrometeoroid or space debris that could actually hit the spacecraft.
It's a harsh environment.
If we send astronauts up with the today’s space suit technology, they would use their
career limit in radiation exposure in one hour of doing a spacewalk.
We're not ready to send humans there now.
W may be at some point.
Robotic technology is ready to go there today.
Here at the Space Robotics Lab at NRL, scientists are developing and testing robots that can
fix broken satellites.
I can see a number of types of servicing.
The simplest would be a tow truck service.
Come up and dock with a satellite and help it get where it needs to be.
The next type of service would be helping with stuck deployables.
Satellites are launched folded up inside a rocket.
Sometimes a solar panel or antenna or other component fails to deploy.
Robotics systems can easily help that deploy.
The next service I would see is doing external upgrades.
We might be able to add a new thruster package or new communications package or something
that attaches to the outside of the satellite.
Rocket surgery will come later.
But how do you get a rigid robot to do the subtle work of human hands?
We're focused on computer-controlled docking because there’s a time delay from ground
to space.
Going to geosynchronous earth orbit it can be as much as three seconds once you factor
in time of flight through space and all the real world concerns.
Imagine you were driving on the beltway and your car turned three seconds after you turned
the steering wheel.
You’d come up with a new way of operating.
That’s what we want to do in space.
We want the computers to do what the computers do best and do the close approach docking
when you having two satellites flying near each other in a relatively risky environment.
We want to get to the point where the computers can bring the docking in autonomously and
then bring in computer assisted and human controlled servicing so we can really get
into the detailed work.
Let the computers do what they do best and the humans do what we do best.
The robot is this arm, which was developed for NRL here on Earth, where there's gravity.
The arm though needs to function out in space where there's no gravity.
So how do we test it here?
The answer: this table.
What is this?
We called it the air bearing table.
The reason for that is each of the mass targets has these green pucks - those are called air
bearings.
They have micropores on the bottom.
We feed pressurized air to them and when we do the entire thing floats on very small cushion
of air like an upside down air hockey table.
Right now this weighs…
what, 200, 180 pounds?
If I try to move it, it's not going anywhere.
But if you were to turn on the air…
So if I turn on the air – and we’ll give it second.
Now it's floating on air.
You’ll notice that it hasn't moved because the table has been grounded to be flat within
2/1000ths of an inch over its entire surface.
But if we push on it…
How much force did you apply there?
Not very much at all.
I used one finger.
Why do you have a giant air hockey table?
This is how we simulate what happens when you use a robot arm to reach out and touch
a satellite that is floating in space.
The air-bearing table basically removes friction from the equation.
The difficult part of being able to just reach out and grab a satellite that is floating
in space is that even though they're very large, if we push on them the wrong way, they'll
float away from us, they’ll start to tumble, and they have really wide solar panels, 50
meters wide in some cases.
If they start to tumble, the solar panel can rotate around and hit us in the back, and
that’s a bad day.
So what you have to do instead is make the robot arm so that it goes where you tell it
to go, but it also senses and responds to forces the way that a human hand does.
So what we’ve done here is we’ve modified the way that we control the robot, so it can
feel forces that are exerted on it by its environment and it responds to those forces
similar to the way a human hand would.
So if we reach out to grapple a satellite and its not exactly where we thought it was,
the robot will hit the satellite, sense the forces, and instead of pushing to where we
told it to go, it’ll stop pushing.
When I'm moving this…
Actually I'm not really moving it.
It's just sensing where I wanted to go and responding to me.
Exactly, it's moving itself.
That is so cool
We launch billion dollar satellites into orbit 20,000 miles above the surface of our planet.
And if they break down or drift away there is nothing we can do about it.
But the experts at NRL are using all their scientific and engineering know-how to create
space robots that function almost autonomously.
If their efforts are successful, this country will soon have its very own tow truck and
repair service in space.