Culmination of PSA Microgravity Design Challenge
Hear from NASA engineers. See what NASA is now doing to test the PSA on
Earth to determine how it will behave on the International Space Station
and find out what they have to say about your designs.
information on this event is available
Read bio of expert Daniel Andrews
>> Explore space, explore Earth, talk to the people
who work at NASA and see what you can really do with science.
Students, teachers and everyone else interested can go online with NASA.
It's easy on the Internet at quest.org.NASA.gov.
>> Hello and welcome to the webcast for the PSA microgravity challenge.
I'm Alicia and I would like to welcome all the students and teachers who
worked so hard on designing their system for testing the Personal Satellite
Assistant or NASA robotic helper.
I would like to start by reminding you we'll be answering your questions
during this webcast in the quest program online chatroom.
Get your questions in early and we'll try to answer as many as we can.
Joining me today is P.S.A.'s lead engineer Dan Andrews.
Welcome, Dan and thank you for sharing your time with us at NASA Quest.
>> You bet.
>> Now before we get started I want to give you an overview of what
we'll be talking about during today's webcast.
First we'll talk about the challenge.
Why is it necessary to simulate microgravity here on Earth?
Then we're going to talk about something called the six degrees of freedom
and why they're important to PSA.
Dan will take a look at each of your final designs submitted by you, the
We'll then look at other test beds or places NASA uses to simulate microgravity
and we'll learn about what the PSA engineers came up with for their robotic
We'll finish the webcast answering your questions through the online chatroom
so get those questions in.
Let's get started.
The first thing we need to think about is microgravity.
PSA is a robot designed to operate on the International Space Station.
In the International Space Station there is a very unique environment.
They're in a State of free fall or microgravity.
What do we mean when we say microgravity?
Those astronauts take a trip around the planet once every 90 minutes.
You couldn't go around the world that fast in a car.
A car can only travel 65 to 70 miles-per-hour legally.
The Space Station travels at five miles per second.
That just so happens to be the perfect speed for Earth's gravity is pulling
down on the Space Station all the time.
The speed of the Space Station keeps it from crashing into the Earth.
It gets orbiting and curving around the shape of the Earth and it keeps
And so that orbit, it's fall, the Space Station is falling all the time,
it just never hits, it just keeps curving around and around and around.
That's the State of free fall or what we like to refer to as microgravity.
We'll take a look at some footage of what that actually looks like inside
the International Space Station.
The effects of living in a free fall environment.
We'll look at astronauts sitting down to a meal and you can see they are
passing around food.
The astronaut is crawling along the top pulling himself.
Things are floating.
Those astronauts are sort of having to put their legs or situate themselves
so they don't float away.
Watch here as they sort of pass some food along.
It will float by.
You can see it on your screen.
So this environment is very unique and the PSA needs to work and operate
in this environment.
Now that you have a feel for that environment we'll talk to Dan and talk
about why this is important when it's time to test something like the
>> Hello, the thing that we have to get addressed here is the issue
of why you need a microgravity environment.
The whole purpose for this exercise that you guys have been participating
When you're up on Space Station or in any spacecraft that is up in orbit,
everything has to work, ideally, because people down here on Earth can't
go repair it.
You have to wait to bring it back down and that's a problem.
What we need to do is come up with a test bed that allows us to be pretty
confident that the robot or whatever the device is that you're working
with is going to work once it is up there.
And so that's why we create a microgravity environment.
What's important to note is there is no such thing as a perfect microgravity
You are also trading off the performance of one part of a test bed versus
another part of a test bed.
We'll get into that a little bit as we go through the student designs
and even what we ended up doing.
The thing I wanted to cover first, though, is the notion of degrees of
This is an important thing to understand because it tells you all the
different ways in which something can move.
And so in the case of the PSA on Space Station, we need to be able to
So we have some slides here of an aircraft that is illustrating a couple
of the different ways, six different ways in which you can move.
In this case we have an aircraft that is moving going forward and backward.
This is what we call the X degree of freedom, all right?
Moving forward and backward.
On the next slide you see side to side movement.
We call this the Y degree of freedom.
Moving side to side.
You aren't turning, you're sliding back and forth.
We sometimes even call it side slit.
This is the Z axis, the up and down motion.
The three axis which you can move along a line, X, Y, Z, forward, left/right
and up and down.
I told you there were six degrees of freedom.
The remaining three are rotational degrees of freedom.
In the next slide you'll see the first primary rotational degree of freedom.
This is roll.
This is where the aircraft can tilt about its wings left or right.
The next slide is pitch.
This is where the nose of the aircraft actually tilts up or tilts down.
So that's the pitch axis.
Then the final one is yaw where the nose of the aircraft can turn to the
left or turn to the right.
Some of these you might be familiar with just in your everyday life.
For example when you're riding a bicycle you can move forward and backwards.
That's the X axis.
You could also turn as this diagram has, turn to the left and turn to
That would be yaw.
There is two degrees of freedom.
Can you move up and down in the Z axis?
So with a bicycle you don't have the Z axis degree of freedom.
What I want to be able to do is illustrate those same concepts from the
standpoint of the PSA.
What this is is a model of the PSA it.
it doesn't work but it illustrates what we're working on.
The front of the PSA is the LCD screen, the X axis motion we were talking
about is moving in and out like this.
The Y axis, which is the side to side motion would be this motion.
You'll notice I'm not turning it while I go.
This is pure Y axis motion side to side.
Finally the Z axis would be when you're moving up and when you're moving
Again, no turning.
So those again are your three translational or movements that you can
make along a line.
The three orientational or rotation degrees of freedom are roll, which
is when you can tilt to the left and tilt to the right, pitch, which is
when you tilt it up and down and yeah when you twist to the left and right.
These are the six degrees of freedom.
If you came up with the perfect microgravity environment you would have
all six of those possible movements to the PSA.
That's hard to do.
Really hard to do.
We've found that out ourselves.
And so part of the challenge for you was to try to come up with environments
that had some degrees of freedom like this, and you did.
So now what I wanted to go ahead and talk about was the design.
Now, the first one we have up here is the new market middle school.
This is the group of 8th graders John, David, Holly, Kate and Macy.
You can make out this structure here.
A rectangular structure.
And they have a mechanism up here which is a chain device that can rotate
like a motor and move the PSA.
In this case the tennis ball, back and forth.
I would consider that the X axis degree of freedom because it can move
back and forth along the length of this device.
I would say this is a two degree of freedom system.
It can yaw, which is where you twist to the left and right.
The tennis ball is down here somewhere hanging by a string from this gantry
system and can twist left and right.
I see two degrees of freedom.
I appreciated a comment from this group that said they wished to include
the Z axis as well, the up/down degree of freedom but their enrichment
funds ran out.
It's something we have to deal with, too.
We're continually trying to balance what we think we can achieve and make
happen, against how much money and time that we have available.
So when I read this, you're right on the money.
That's a real world issue.
The next student submission for final review was also the new market middle
This is a different 8th grade group.
In this case the basic structure to me appears to be very similar.
You have a gantry-type structure along the top that is motorized.
I see an X axis degree of freedom here.
You see the PSA ball represented by a tennis ball here.
And so it also, because it's a string, has a limited amount of yaw degree
It couldn't spin around and around or it would wind up the string but
it could turn 90 degrees each direction.
The system would allow it.
They did have enough enrichment funds and got a Z axis motor installed
here which allows the ball to actually move up and down.
So I'm seeing three degrees of freedom in this system.
The next submission was Caroline Robbins community school in Canada, the
fourth and fifth grade group.
In this case I'm seeing a two degree of freedom system.
The way I've come to understand this work is this is a remote control
Dark on the bottom but it can be driven.
The PSA is represented by the tennis ball.
They've got these cardboard structures here.
There is a string that goes through the tennis ball and up the other side.
The two degrees of freedom I'm seeing here are X again, because this thing
can move back and forth along this axis and I'm seeing roll which is the
one you can turn left and right roll.
Because the string is going through the ball.
Now, in order for that work you would want the string to go perfectly
through the center of the ball otherwise it would wobble as it turned
and be difficult for the PSA to move.
In principal that's what this is getting, two degrees of freedom.
They also provided a string that came down from the bottom of the tennis
ball so that you could pull it down and release it and that did give a
Z axis motion.
In that case, though, I don't see that as a way for the PSA to actually
drive in the Z axis.
It appears it's more of a control thing.
I wouldn't consider that a working degree of freedom.
I see two degrees of freedom here.
The final one we have is the new market middle school 6th grade group
Jordan, Chris, Michael, Michael and Al.
And this to me looks like a four degree of freedom system.
The clever parts of this design is they used a whole bunch of Valentine's
Day helium balloons to neutralize the weight of the tennis ball, the PSA,
some sand, platform and looks like some electronics that probably run
By putting sufficient balloons up here they've cancelled gravity from
the standpoint of the Z axis.
So what that means is if that were a real PSA hanging there, if it wished
to move up and thrust upward, the balloons would just move up and same
for going down.
They basically would cancel the gravity part for the Z axis.
If the PSA wished to move in X, in Y, balloons would also allow for that.
All three linear degrees of freedom.
I believe there is a fourth one, and that is the yaw axis.
If they were to tie them to a single string and have the PSA hanging from
that you could get a limited range of yaw motion.
I thought this was a very good approach and I'll be talking more about
this with respect to some of the things we had entertained in our own
So now I'll turn it back to Alicia who will be talking about some of the
NASA microgravity system that we have available.
>> So part of your job was to try to find a test bed that was appropriate
for a PSA and you're aware there are already ways that NASA uses to test
things in microgravity.
We'll talk about three of those ways and have you comment on why you chose
or didn't choose those particular test beds for PSA.
A lot of people out there walking around thinking that NASA has this special
microgravity room where you can go in, turn a switch and turn off gravity
and things will start floating up and you can test your equipment and
astronauts can be trained and that's how we do all of that.
Well, we don't.
It's not a big secret.
We aren't hiding this room behind a curtain here.
It is not possible to escape gravity.
We're on this big rock and we have to deal with it.
We can do some things that can give us apparent weightlessness.
A lot of those have to do with falling.
One is through a drop tower.
It works on the same principle that an elevator might work.
You might have had the experience of standing in an elevator and the elevator
starts going down and you feel the tickle in your stomach.
Your stomach is telling you that you're going down.
The body is sensing the movement.
In an elevator it is controlled and it will stop you and you can get off.
A drop tower.
Imagine if you can put the person at the top of the elevator and cut the
cord allowing the experiment to drop down eight stories.
We have a picture of the drop tower from Glenn Research Center in Cleveland,
They load the experiment into this container, they put inside cameras,
computers, monitoring equipment.
It wouldn't be very safe or big enough for a person to ride inside this
They send it up to the 8th floor, release it and down it goes in 2.2 seconds
it travels eight stories.
We have some video of that actually happening so you can take a look at
what that looks like from the top as it falls down.
See if we can pull that video up and you can see how quickly it takes
to get to the bottom.
Down it goes in 2.2 seconds it's at the bottom.
While it's falling, you have that sensation everything inside that container
is all falling at the same rate of speed in free fall.
During that 2.2 seconds you have microgravity and free fall.
Things will appear to float and you'll have the same situation that you
would have in space on the Space Station.
If we want to show that video a second time.
It happened quickly.
So if we can queue it up for time number two you can watch it roll again.
See how quickly it happens?
We'll press the button and down she goes.
So, Dan, you didn't choose the drop tower for PSA.
>> There is a few problems with it.
First of all the 2.2 second business.
If you're going to be testing out a microgravity arrangement to test the
It has a lot of functionality.
The first is that it be able to move around, take sensor readings, avoid
2.2 seconds isn't enough time to get a read on how well the PSA is doing
so it's not very practical as a means for testing.
Furthermore, despite the fact that the object that is being dropped does
land in a box of foam and cushions and so forth.
That would be a pretty hard environment.
I would be worried about the electronics and survivability of the robot.
>> No drop towers.
Maybe you could test that in the NBL.
It stands for the neutral buoyancy lab toefrment -- laboratory.
It is located at Johnson Space Center in Houston.
They have astronauts training on huge mock-ups of the International Space
They're able to put full-sized pieces of the Space Station that looks
and acts like the Space Station in microgravity.
They can put the astronauts in the full space suits and they can practice
space walks and practice working with the tools they would have to work
with on an actual space walk.
So the name of the laboratory is neutral buoyancy.
Even though they're in a 300 pound suit we have video.
This suit is so heavy the astronaut can't walk around in it on Earth.
They use a crane to lower the astronaut down into the pool where they
can practice and hopefully we can bring some video so you can actually
It is airtight.
They have oxygen tanks that they can breathe and he is being lowered into
the water there.
What they'll do is they'll either add floats or weights to that astronaut's
body to his or her suit so that she doesn't think and she doesn't float.
It's neutrally buoyant, neutral.
It simulates microgravity so the pushes and pulls don't send you floating
or sinking because of the water but because of the forces you're actually
creating by moving around.
So PSA, is it a good idea to test it in a facility like the NBL?
>> It does provide full six degree of freedom capability.
You can move in X, Y and Z and turn in roll, pitch and yaw.
That makes it a great candidate.
It is also very big.
That means that you can do a lot of functional checks of a robot.
You can steer over here and take a pretend reading of a sensor, steer
over here to avoid objects.
Everything you describe makes it an excellent place to test.
The problems come in when you look at the fact we have water.
The PSA is an electronic device and it is very porous.
That means there are holes all over it on purpose for air to be drawn
in and hot air to be able to be expelled for cameras to poke through to
see what is going on.
All of this will be filled with water.
Even the propulsion is by sucking in air and pushing it out in a different
Now it would be sucking in and pushing out water.
Not a good environment.
Even if you were to take the time to waterproof the PSA and make all the
internal components waterproof and all that, there is a problem in the
neutral buoyancy lab in that you're in water and as you know when you
guys are in a swimming pool or at the ocean or whatever, if you walk through
the water it is not so bad.
You can walk through it.
Have you ever tried running through the water?
It's a lot of work because all that water, as you're moving quickly, has
to move out of the way of your legs.
In the case of the PSA it would be a much harder job for it to move around
in water than for it to move in air.
Since it will eventually be in air within the Space Station, it doesn't
make for a very good test.
>> The NBL is out for now.
One of the other test beds that is a lot of fun, actually, is the KC135.
It's a research aircraft that flies out of Houston, Texas and the other
name that is often referred to as the vomit comet.
And if you take a look at this illustration of the flight path of the
vomit comet you can probably figure out why they call it that.
Flies up to 25,000 feet and then it starts doing these rollercoaster maneuvers.
It goes up and down 30 to 40 times in a two-hour period and while it takes
about 20 seconds to get up to the top of its curve and then it falls over
that peak just like if you were in a rollercoaster car and you fall over
the top of that and you get that tickle in your tummy, that feeling of
falling and that is really what they're doing in this aircraft is they're
throwing it over a curb and letting it fall down to the Earth in a controlled
When they get to the bottom they start over again.
A lot of up and down motion and your stomach certainly knows about it.
And I had the opportunity to fly on the KC135 about a month ago and luckily
I didn't feel any of the ill effects but I can't say as much for some
of my research team.
Vomit comet is definitely an appropriate name for some of my pals who
flew with me.
Here we have about 25 to 30 seconds of microgravity.
You do get a little bit of a feel more than the 2.2 seconds of the drop
tower for example where things are apparently weightless.
Why or why not might this be appropriate for PSA?
>> In the case of the PSA, this KC135 might be a good choice.
It's in air, not water, I like that.
It's reasonably big inside so I have room to move around the robot.
And so that's good.
And it has all six degrees of freedom available.
Another thing that is good.
So far it sounds like a perfect match.
The only hesitation that I would have is that with the 20 or so seconds
that you have available to test, you still are somewhat limited in what
you can do.
When you think about it in some video you'll see soon, you have to just
at the right point in the curve of the aircraft's flight you have to get
this initialized and set it up in just the right position and release
it in a favorable way.
In a way in which it is just floating there.
Then you have a few seconds, a couple dozen seconds to be able to go about
and conduct a move or something before gravity starts to reappear as the
aircraft is coming back down and heading up for the next cycle.
It's a valid environment, a good environment.
My only concern would be it's still rather short.
There is a lot of work to do to get these things working.
It is not very practical to be spending years in an aircraft going up
>> It would be very expensive as well.
What you're talking about is true, the time before you go into the free
fall and as you're coming out is hard to get -- you can't know exactly
when it is going to happen even though you have somebody in the aircraft
telling you they're getting ready to go in.
Getting it right where you need it to be is difficult.
Once it's on his path the flight director will call out coming out.
That's the point you better make sure your feet of at the bottom of the
You'll hit hard.
You'll experiencing two times the gravity you would sitting here like
we are now.
So you really need to have a lot of control.
You want to make sure PSA is under excellent control so when that -- when
you do enter that 1.8G's it's not out of control and goes crashing down
to the bottom of the aircraft.
That would be bad.
>> I don't like that, either.
>> Not good.
So those are the three different test beds that NASA had available but
those obviously, as you pointed out, aren't a great test bed at this point
in the PSA's development.
What are some of the things you did think about when you had to develop
a test bed for PSA?
>> In the case of the PSA we had everything available to us.
What I mean by that is we didn't have any pre-conceived notions about
what we wanted to do, we just knew we wanted to create something that
lets us get as smart as we can with the design of the robot while here
on Earth and something we could use day in and day out.
So we came up with a bunch of different ideas.
We have a slide here of one of the--
>> Did we show the video of the KC135?
Let's take a look at that before we talk about your engineering ideas.
We have some video of using something that looks similar to PSA.
>> He lets go and there a ball goes up and look what happens as
it comes back down?
Why is it coming back down?
Here he lets go, goes up, didn't have to catch it here.
What is happening there is you're witnessing the aircraft go through its
When he releases the robot and it sits there, that is when you're in a
perfect microgravity environment.
-- no reason for it to go anywhere.
If you see it start to go up and what is happening is you're seeing gravity
starting to be reintroduced into the equation up or down.
You can see how limiting that would be if I was trying to test how good
the PSA was going to be working.
That would be a tough environment.
What you would use that for is when you think your object is working fine
and wanted to validate it where it's floating, this would be a good way
to do it.
NASA treats it that way.
The KC135 is seen as the last checkpoint prior to going into an actual
>> So in terms of the things you looked at when you first started
thinking about ways to test PSA, what are the kinds of things you thought
>> First we thought very simply.
We like simple if it will work.
The first notion that we had considered is that of a mobile.
Some of you may know what a mobile is.
In effect, they are sometimes seen as toys or decorations in baby's rooms
It's basically a construction of two different sticks that are hung from
a ceiling or beam or something above and the sticks are free to rotate
by way of the strings in which they're hung.
If we were to take the PSA and attach it to one of those sticks, and then
have the PSA try to drive and fly like it's in microgravity the sticks
would all start rotating and swinging to accommodate in in its motion.
That would be pretty inexpensive, wouldn't cost much.
It would be very big.
In order to hold a big PSA it would have to be able to handle the weight.
We did a study.
What we did was a computer simulation in order to better understand the
physics of what is happening in a mobile.
We have a quick video clip that involves a PSA undergoing tests.
You'll notice it doesn't look like a red ball.
In this case it's the cube on the end of one of the sticks.
A quick little clip.
Let's go ahead and show that.
Do you see it moving here?
See the cube flying through?
As it's moving it's actually drawing out an arc.
What I mean by an arc is it's not moving in a straight line but kind of
moving like maybe my fist is moving around my elbow.
And so that's a problem if we wish the PSA to move in a straight line.
And so we thought well, nice idea but it is kind of limiting.
It also doesn't have a good Z axis capability and the pitch, yaw not so
We got rid of that idea and went to the next one.
Someone came up with the idea of a blimp or giant helium balloon.
In this case one of the student groups had come up with the same idea.
Basically cancel gravity for the PSA so that it's not an issue and then
when the PSA tries to move up and down it can and in X and Y, everything
It isn't a bad idea.
The hesitation we had here was if you carried a large balloon outside
and walking or there is a breeze you'll notice the balloon gets tugged
on because it's this big thing and the wind loves to pull on it.
It doesn't have much weight.
What that means is that the PSA, when it tried to move underneath this
balloon, it would probably feel the drag of the balloons.
It would actually feel the fact that it's not actually in a microgravity
That one wasn't thought to be such a good idea.
It would be very limiting.
So then we went over to the idea of a granite table.
And what a granite table arrangement is is like an air hockey table in
Instead of air coming out of a table and a disk scooting across the surface
with almost no friction it's a very flat, hard table and we put air within
the fixture to hold the PSA and blow down.
We have video of this actually working.
This is an early version of PSA.
It looks nothing like our red ball PSA.
It's the electronics we had to later shrink and fit within it.
It is floating on this granite surface here and can move in three degrees
It can move in X and Y, I think you can see that.
It can also spin in place.
That would be yaw.
Two translational degrees of freedom and one rotational.
That ends up being a very effective means to start out testing the controller.
We have another video coming up and this is showing a later version of
the PSA and in this case you'll see that we are starting to package the
electronics within a shell, within the sphere.
Here it is here.
It's on a very similar platform or plate that you saw in the previous
Here we're testing one degree of freedom, yaw.
It's spinning in place.
And I could tell you, you can't hear it.
As it's spinning here it is only pushing through part of that and then
The PSA was trying to slow down and thrusting in the opposite direction
to stop it in its position.
This is a very good test and illustrates the potential microgravity test
We have another video after that that shows a translational degree of
The X degree of freedom.
In this case we have the same rig.
Here the PSA is not trying to spin, but it is actually trying to move
across the table.
So you see we set it up and now it's driving across the table.
The guy on the other end to make sure it doesn't fall off onto the floor.
And he set it up and off it goes again in the other direction.
This has been very useful for us to test our early degrees of freedom.
Do you get all six degrees of freedom all of that?
No, you can't go up and down.
You can't leave the table.
You can't pitch and you can't roll.
You can just yaw.
And so does that mean it's a bad idea?
It allowed us to get smart with what we need to know first before we got
what we eventually came to.
A full microgravity test facilities that has six degrees of freedom.
Very complicated and an evolutionary things.
As we try things out they sometimes don't work and we try other things.
We have video now of a guy on our team named Mike who is showing its yaw
In this case there is no motor driving that.
Mike gave it a spin and it's spinning on its own.
It is not slowing down.
That's exactly what we want.
We want this thing to spin forever if it could.
It won't, but it spins a very long time.
The red disk you see in there is the -- what we call the dummy weight.
It weighs the same amount as the PSA and allows us to test what is going
on without having the ball in there.
Someone else is working with the robot off camera.
He's testing translation.
This is a Y axis move.
He pushes it and then it takes off.
And then he lets go and it keeps moving.
He introduced a little bit of a spin at the same time.
That's what we're looking for in all six degrees of freedom.
>> You don't want the PSA to sense it is attached to anything.
It's to give it full freedom and the feel that it's really in microgravity.
>> That's right.
In fact, we don't have any software in here or anything in the robot that
helps it cheat.
There is nothing in here that lets it know it is in the crane so you need
to push harder here or do that.
It really believes that it is operating in the microgravity environment.
Our job in designing the microgravity test facility is to make that as
true as possible.
As I said in the beginning, there is no such thing as a perfect arrangement
good enough and make your design work well you have the problem nailed.
The final step I believe we have some video here of the PSA moving in
multiple degrees of freedom.
So here the PSA is not actually powered at this point but we're pushing
You notice the person behind there is not touching it anymore.
It is just coasting towards the camera.
In fact, it would possibly hit the camera or rail if he hadn't stopped
That's what we want.
It should just keep going.
You can see in the backdrop there, that's the mock-up we have of the Space
Station so the vision system on the PSA gets a little bit of a sense of
what it might look like on station.
We don't have all the black disks there but, you know, it is our first
step in getting the vision system working.
>> What is the size of the room they're in right now?
>> The room is matched to the size of the Space Station.
One of the U.S. labs on the Space Station.
So roughly speaking it's about 9 feet tall.
9 feet wide and then it's as much as 33 feet long.
So you have a nice long area in which we can test.
Remember I was talking before about some of the other test beds.
We need room to test.
We need room to see if the PSA is actually able to accomplish what it
needs to accomplish.
So I think that's the end of those videos.
What I would like to show now is some video of actual movement on the
Give you a sense of how things really move.
You've probably seen stuff like this on television and it will help you
get a feel for how things really need to move in our microgravity test
You can roll those.
>> Hopefully you should try to look for similarities in the way
these objects move to what you just saw in the test bed.
>> As you see here nobody is touching that.
It's just floating and it has multiple degrees of freedom.
Twisting two different ways and moving away from its hand.
There is some candy just released out of the hand.
It will stay there forever or it will keep moving forever.
Unless someone eats it.
And then here is just a multiple degree of freedom little toy and no one
is touching it and yet it keeps going.
That's the whole point of this.
If the PSA wished to do something, wished to move like this droplet of
water is moving the test facility we would want to allow it to do so.
That's our goal to look like that.
And so now I think we have video of the PSA actually driving in our microgravity
I'm sorry, so now what I'll talk about is the facility itself.
What we have here if we can pause it with Mike's hand there, what we have
there is a structure, the actual system that we've created to make the
And we're going to be able to talk to that specifically in a little bit.
What you have there is some sensors where Mike is putting his hand in
there to show a red dot on the back of his hand.
That's actually a laser beam.
There is a red dot on the back of his hand.
The laser up above monitoring what the PSA is doing.
So the laser is not hurting his hand.
It's like a laser pointer.
But when the PSA tries to move, that laser actually is tracking the PSA
and the crane tries to follow it again trying to preserve the microgravity
What I would like to do now is actually talk about our MGTF as we call
Microgravity test facility.
We have some stills I would like to show you of what it is.
This is a diagram, not a photo, of the whole facility.
You can see that it has sort of a tunnel look to it.
Remember those images we're addressing it's kind of a long tunnel, 9 feet
by 9 feet by 30 feet or so.
>> What we're looking at is the skeleton shape of the room we just
There are no racks shown here.
This is what is behind all the racks and what is behind the scenes.
I would characterize this degree of freedom as the X degree of freedom.
And the Y degree of freedom would be moving across X.
Back and forth on this little trolley here.
Then the Z degree of freedom would be moving up and down.
You remember those from my initial description degrees of freedom.
So there is your three sort of linear or motion along the line degrees
Then you have the rotational ones within a gimbal structure that you'll
We've already seen in some of the video.
So next slide.
This is the same facility, a little different angle.
What you can see now is the racks are in place.
It gives you a little better feel for what you are looking at in the video
before that you saw all those racks with this funny black disks and everything.
It is actually built into this structure here to make it realistic, as
I said before.
So this is a zoom in on the Y axis part.
The X axis is still along this axis.
Here is the Y motion that you can do.
There is a little trolley that rides on it.
Here is a gantry that move up and down.
Y can happen back and forth at the same time.
How do you get Z axis, up and down?
In place of that little trolley I showed you in the previous slide, this
is a very complicated mechanism that we have that allows us to get the
Z axis degree of freedom.
A series of pulleys and motors and so forth.
What it's doing is taking this PSA robot down here and enabling it to
move up and down, Z axis, while the carriage is moving back and forth,
Y axis, and then the whole gantry is moving up and down, X axis, all three
at the same time.
As you see in the video, we need to have that in order to really represent
a microgravity arrangement.
I think we have one more slide here which shows sort of a detail of the
Pretty complicated thing.
This is an example of a design where we thought we knew how it would work
at first and it worked pretty much that way but not quite as well as we
We had to modify the design, go back, try some things, eliminate some
It's been an evolutionary process there.
So that's it for how our facility actually works.
I think we have one more video which shows the PSA actually driving around
inside of it.
Here we go.
So in this case the PSA is actually powered.
It had a tumble at first and it's powering through it.
It's no longer rotating.
It is straightening up and driving toward the back of the mock-up, the
This is the PSA really believing that it is in a microgravity world.
It is doing its thing.
And the crane's whole job is to make sure that it is faking out the robot,
So the degree to which we can do that is what we're after.
Well, thank you, Dan, for sharing with us.
It sounds like it was a pretty involved process that took a lot of problem
solving and a little bit of frustration but looks like you have got something
working pretty well for you.
At this point we're ready to answer your questions.
We have Linda over here who is running our chatroom and she has some questions
to ask of Dan.
Yes, we're just starting to get the questions in.
A lot of people were a little confused about where the final designs were
Please notice I put the URL into the chatroom and you can take a look
at them there.
I have a question here that says how does the granite table idea work
Or how does it differ from a hover craft?
>> Actually the granite table works a lot like a hover craft.
If the hover craft you're referring to is the type you might see hovering
over water like a boat-type vehicle that schools along the top of the
water it's exactly like how that works.
The water is relatively hard compared to a fast-moving boat and so the
PSA -- so the boat basically hovers across and scoots along the surface.
In the case of the PSA, the PSA is sitting on that plate.
Remember that big silver plate there?
We have a little pump sitting on that plate and that pump is continuing
to push out air underneath the plate.
Sounds a lot like your hover craft idea.
Because the granite table is one, very flat, and two, very hard, the air
is forced to distribute all over underneath the plate and that means the
plate is no longer rubbing the graint.
When the PSA says go it doesn't have anything to slow it down.
It scoots right along.
Our analogy to a hover craft is right on.
I think we've had a moment of aha with something we were talking about
New market middle school students want to know, was the machine we created
supposed to be used on the ISS itself for just for testing here on Earth?
>> When I was reviewing some of your proposals and having a dialogue
with you it did become apparent to me that some of you thought this whole
thing you were creating was going to go on station.
And that as I think you've learned, is not what we were trying to do.
What we were trying to do is create an environment here on Earth that
would make the robot think it is on station.
Think that it is in space.
So the idea of moving this whole thing up there given what we're after
and doesn't make sense in that way.
What we're trying to do is fake out the robot here on Earth so we don't
have to do things like spend all day going up and down in an aircraft
or inside a pool and doing all that.
Do it all here, work out all the bugs and bring it up on station.
This person wants to know when do you project the PSA will make it into
>> This is something we are struggling with right now.
You know how your work that you did in this was based on the requirements
that were put on the webpage, right?
You looked at the requirements and said OK, I see what they have to do
and so forth.
I have to do the same thing and our team has to do the same thing.
How do we wish it to be used what are the requirements and who is our
Who is deciding what it should be?
That right now is being visited in light of the president's new agenda
for going to the moon and to Mars.
And so we are assessing that right now.
We're probably a few years out for actual deployment on something like
a Space Station or the like but we're hoping sooner than that to be able
to actually do some of these tests beyond our microgravity test facility,
such as going onto the KC135 and eventually a quick shuttle trip or something
like that that allows us to more accurately see if the PSA is performing
the way we thought it would be.
You're going to get me trying to answer a question in the chatroom.
Jerry wants to know, does the crane move the PSA around or does the PSA
have its own way to move?
This is a very good question.
The PSA has its own way to move.
That ball that you saw in the video was a real PSA.
Its our latest prototype that works and it has fans that you probably
couldn't see very well.
The fans are turning and are actually driving, OK?
So the PSA is really moving.
But the thing is that the PSA can't drag the crane along with it.
The PSA isn't designed to drag a big heavy metal structure around.
So the crane carries its own weight, the PSA carries its own weight and
the idea is if you get that just perfect or close to perfect, then the
PSA really thinks that it is just driving itself around and that's what
The crane takes care of itself, the robot takes care of itself and everyone
Again from new market middle school students.
How long have you planning for the PSA to be in space?
>> If the PSA works properly, there is no reason it couldn't continuously
be up in space.
There are maintenance issues with your car, you have to change the oil.
We don't have oil in here but there are issues you have to address.
As long as the batteries are holding up.
You can recharge the batteries.
I didn't talk about that.
The batteries are a rechargeable thing.
So when the PSA is out and about doing its business, it's sensing and
taking video and doing all that.
When the batteries are detected to be getting low, it has to go home.
By home I mean back to its docking place within the station park and at
that point, through tabs on the back of the PSA, it's actually getting
So the internal battery is getting recharged.
When it's done charging it can go ahead and deploy and go about business.
We've always thought it might make sense to have more than one of these
so one is always available while one or two are charging back in their
I'm just going to answer one logistical question because I'm getting --
I think there is a classroom on who hasn't identified themselves yet who
thinks they're supposed to be a winner here.
And I just want to mention that this is a design challenge.
There is no right answer.
And we are not judging one up against the other.
As you noticed from Dan's description at the beginning of the broadcast
or 15 minutes into the broadcast each design has its pluses.
Each design, as is the real design that Dan and his group are working
with, even has its flaws.
Or where it can still build to become better.
So this is a process.
This is a design process and it is not a competition.
>> I would like to say something as well along those lines.
You may notice when I describe the four final submissions that were given.
There were little aspects in each of them that were what we ended up doing,
at least that we had considered.
The helium balloon idea was something we directly considered and for reasons
we chose not to do that but it's a great way to knock off microgravity.
In the first two I talked about that gantry idea of a crane system being
able to carry it back and forth.
That's how our crane ended up working, so that's a good part of that.
There are lots of ideas.
The roll mechanism of the third one we talked about.
We created a gimbal system that in effect grabs the ball in the center.
I made the point about grabbing it in the center and allowed it to roll.
That team used a string going through the ball.
You accomplished the same thing.
There is no one right microgravity including ours.
I wouldn't say ours is the answer but one we've gotten to work and therefore
we're happy with it.
There really isn't a winner.
That's the nature of design.
The question is, does it work.
I have a question here from from Carolyn Robbins in Canada.
What precautions does NASA take if there is a power failure of the PSA
>> That works two ways.
Let's say the station were to lose a critical power, you know, capability.
All the lights were to go out or some sort of sensor array would die because
it would lose power.
The PSA is separately powered.
It has its own batteries.
It can go out and explore things when the rest of the station is potentially
unpowered or in a bad way.
So that's a great example of the PSA saving the day potentially.
The other way around, which might have been your question, though, is
if the station is fine but the PSA itself either loses power or something
maybe goes wrong and it goes crazy and takes off.
That is an issue that we are going to have to address when we get closer
to a flight model.
By a flight model I mean one going up on station.
Since you can't ever guarantee that something bad won't happen, you never
really can guarantee it, what you do is you try to take precautions.
And so you've seen this hard plastic shell that we've talked about here.
That's fine and it works for our needs but on the PSA that is deployed
we may very well at least on the first one or two actually have a foam
cover around it.
And we can design a foam cover where it is built the same way the shell
is that has perfect openings for each of these different elements, an
opening for the screen and we could maybe snap it on like a glove and
maybe it has a half inch of foam on it so that if it were to hit something,
a wall, a cabinet, a tool, probably wouldn't cause any harm.
Good questions and I think we've only started to scratch the surface on
what we'll have to do to address this.
Students want to know how many PSA's will NASA send out into space at
>> Can't answer that one yet.
Right now we're still trying to prove that the PSA is a working, useful
We're a little bit earlier than what you're asking.
As far as what I could envision.
Let's say it does everything we're trying to make it do.
That it can take video, that it can monitor sensors.
It could be a safety device, it could be a laptop.
A PDA, all these functions.
If it successfully does that, why wouldn't you put one of these on every
Why wouldn't you put it on the spacecraft that goes to Mars or the next
In fact, on a very far away mission to go to Jupiter or something where
it's not really reasonable that humans get on because it takes so long.
Why wouldn't you have a few of these basically doing maintenance on the
There is a wide range of possibilities where the robots could be running
the mission or doing housekeeping for the spacecraft relieving the need
to have humans go.
I think we're just at the beginning of what all these types of robots
New market wants to know if they helped you any.
Are you any closer to a solution?
>> You know, when I read these submissions, including the ones that
didn't go all the way to final, I was actually pretty pleased to see them.
This is going to sound kind of strange because we're NASA and we're supposed
to know everything.
When I saw that the ideas that you came to were some of the similar ones
that we had it actually was reinforcing to me because it would have been
terrible if you came up with a really great idea that we missed.
What I was glad to see is you were thinking just like this us.
You don't have some of the same tools we have, computer capabilities,
the money, all that stuff.
So we can do more than you can do.
But the basic ideas of how you do it is what really matters.
That's the germ of the idea.
And almost all the submissions were right on the money.
>> I have a question as to whether or not I was Linda Conrad.
Yes, I am.
Question from bill.
Will we ever be able to use the PSA at home?
>> You know, ever since we've been testing the PSA at home, meaning
in the crane here at NASA Ames Research Center, whenever people come and
visit that's one of the first questions they ask.
Well, you have this crane thing and it works great and I see how it would
be helpful on a spacecraft but what about a home?
And we ourselves, our team, are not presently working on that because
we're focused on the goal that I've already stated about creating a robotic
assistant for space.
There are other people who are very interested in having something like
The military is interested in creating something like this so it would
work on Earth and I know there is plenty of consumer product companies
out there who would love to have as I heard discussed before today's special
a kitchen helper, right?
Something that buzzes around the kitchen.
Stays out of your way, not annoying but has everything from recipes to
where this is located.
Go find the wrench, that spatula.
Can I check email while I'm stirring this?
You have to open up your mind and consider all the possibilities.
That isn't our job right now but I think that is a natural evolution of
this type of thinking.
>> We're getting very close to the end time of the webcast and so
I want to just close with a question from -- let's see -- I guess this
is the NMMS.
How can we become more involved in building a PSA?
>> Well, with respect to building the real PSA, go to school, go
to college, get good grades and all that stuff.
With respect to building your own which is actually more interesting to
me, when you look at people who do what our team does on the PSA effort,
they started at ages like most of you and maybe even younger tinkering
and playing around with stuff.
Sometimes taking apart stuff they shouldn't have but learning how things
work and all the rest.
That's the best thing you can do to prepare yourself as you do go on in
school and learn more tools and mathematics and science and physics and
all this stuff.
That's the best preparation you can get into to eventually doing a job
like what we do.
Or maybe something slightly different.
Maybe even more interesting than the PSA.
Just stick to it and keep playing.
Because that's what tickles your mind.
>> Good advice, Dan.
And so with that, I would like to thank all of you, all of the talented
students and teachers who participated in this challenge.
I would also like to thank NASA engineers Dan Andrews and PSA for sharing
your time and work with us.
Our final video today will be a look at how PSA might be used on Space
Station to solve a problem.
And so enjoy the video and thanks for joining us.
>> Copy that.
Stand by, payload.
We confirm a temperature increase of unknown origin in life science payload
one Oscar three.
Food schedules are set.
We recommend deploying PSA to investigate.
>> Roger that.
Command initialization sequence.
>> Payload, PSA confirmed deployment.
Performing 90 degree Y axis rotation and moving to life science pay road
one Oscar three.
>> Life science payload rack one Oscar three.
Initialized, beginning infrared sweep.
>> Copy that.
We've got a real good signal here.
Emanating from the adjacent payload rack.
>> Following up, ventilation fans to dissipate the excess heat.
>> Standing by.
Quest Home Page
Responsible NASA Official: Tom Clauson
NASA Ames Research Center, Moffett Field, California, USA