>> Hello, and welcome to the closing webcast of the NASA Quest "Exploration Through Navigation: Voyages Acrss Sea and Space" webcast.

Today marks the end of our most recent task of charting a course to the Moon.

My name is Rebecca Green.

I am here with three other key individuals at the NASA Ames Research Center in northern California.

First we have Linda Conrad, the challenge coordinator and she'll be fielding your questions today.

Be sure and submit your questions right away so we have time to answer as many as possible at the end of the webcast.

We also have Brian Day with us.

He's an astronomer and expert on the LCROSS mission.

Today Brian will be giving us updates on that mission as well as pointers related to the navigation plans that you've submitted.

We also have Mr. Andrew Chaikin with us.

He's an author, science journalist and space enthusiast and been the mastermind behind the weekly challenge questions and the problem situation that you were given in early April.

So today Andy is going to give comments on all of the navigation plans that we've received and offer some feedback on the work that you've done.

I want to welcome Brian and Andy and Linda off to the side.

Before we get into the navigation plan review let's look at this challenge and see what it's been all about.

Some of you may have participated with us in the fall of 2008 where we did part I of our challenge.

This was charting the course at sea.

During this part you had to navigate a ship across the Pacific ocean from Hawaii to Rapa Nui.

Nearly a 5,000 mile journey.

You learned about different navigation skills such as looking at the stars, the motions of the Sun and Moon and landmarks, sea marks, weather patterns, etc.

Then we progressed on to the second part of our challenge, charting the course to the Moon.

And in this particular challenge we learned about several things such as gravity, Newton's laws of motion, rockets, orbits.

If we could -- we're looking at our next slide now.

We have several different images here representing some of the things you've been exploring over the past several months.

And then what we want to do briefly is take a look at how these two parts of the challenge connect.

So we have a brief compare and contrast that we want to do.

If we look at Earth navigation we had weather, clouds, animals.

In space we've learned that gravity, orbital trajectory have helped us navigate in space.

One thing they have in common is celestial navigation.

The movement of the Moon and the Sun and the stars can help us whether we're in space or on Earth.

We can navigate our way.

Let's talk about that for a minute.

Brian and Andy do you have any thoughts about you have navigating on Earth versus outer space are similar and different?

>> Good point.

One of the things that we've grown very used to when we do our navigating around just in general daily life is having something like a GPS or maybe a compass.

But in the case of the Polynesia navigators long ago they had neither of those.

In the case of our space travelers today, when you go out into space and leave the Earth behind your compass no longer works, you leave the Earth behind your GPS no longer works.

So in a lot of ways our adventures into space today have some very important parallels with the types of navigation that happened when the Polynesians spread out across the Pacific basin.

>> That's right.

And I think it's neat to think about the fact that even though we live on the Earth and we don't think of ourselves as being space travelers while we're here on Earth, we are space travelers and the Earth is a planet.

It is a celestial object just like the Moon and the stars, and so even though the Polynesians were using the stars on Earth and space travelers use the stars for navigation while they're in space, they're the same methods.

They're the same fixed celestial bodies that give us our reference points and allow us to get from one part of the Earth to another or one planet to another.

>> Exactly.

So let's go ahead and take a look at some of the navigation plans that we've received.

We received 17 navigation plans that represent 400 students across the world.

So let's take a look at them.

Let's start here with our first navigation plan and give some comments.

>> Right.

We've got the workman orbiters from miss Jamison's sixth grade class.

I want to say everybody did a great job, everybody put in a lot of effort and the creativity and thought that went into these plans really comes through.

With the workman orbiters I'll say as I go to each one I'll say something that I really liked in each case.

I thought the name lunar eclipse was a great name for the spacecraft and also a very nice chart showing that they are going to aim for not where the Moon is now when they leave Earth but where the Moon will be when they arrive there.

I thought that was very nicely thought out.

Next we have Allen's full throttle flyers from miss Purell and miss Allen's group.

They had some very nice graphics in their presentation and intrigued by the name of their spacecraft, the 14th source.

I'm going to suggest they send an email explaining how they got that name because that intrigued me.

Next we have the nerdy Moon missioners from Ms. Purell and Ms. -- I like the design they have for the unmanned rocket they have to send their spacecraft to the Moon.

Nice job.

Next we have Purell's water seekers from Ms. Purell's sixth grade silence.

I like the reference to Apollo in their name.

I'm a big Apollo fan and I liked that they were tagging up with Apollo and calling it Apollo, 2009.

We have the homeschool, guess what they chose for their spacecraft name?

I think it was the most unusual of any of the names.

A name that makes me hungry because it's I believe it's a spinach pie in Greek cuisine.

I like the fact they mentioned the DeLaval nozzle which is a very important part of any rocket.

The pinched nozzle that causes the exhaust gases to accelerate as they leave the engine.

Very cool stuff.

Next up we've got a fifth grade class in Savannah heights, intermediate.

They had a nice diagram with their navigation and all the stars that they were going to site on as their navigation references going from the Earth to the Moon.

Next up we've got Ms. Roger's seventh grade class and Julian team astronaut.

Very nice graphic of their orbits that they're going to use on their flight path to the Moon.

Next we have the fifth grade from or liens elementary, miss courier's class.

They mentioned the home and transfer orbit, a minimum energy tab used to go from the Earth to the Moon on many missions.

That was a good thought.

And they had great artwork of their rocket.

I really liked the work that they did on that, too.

Okay.

Now we go to the seventh grade class in Romania, the silver stars.

They even had a flash animation of their rocket going from the Earth to the Moon.

I thought that was a lot of fun.

After that we have the ninth grade I class.

They had a detailed mission design, a lot of thought went into the design of their mission.

I like the fact that they mention several of -- several of you mentioned that it is a good idea to launch from the Earth's equator because that is where the rotation speed of the Earth is highest and you get the biggest boost from the Earth's rotation itself.

So nice job there.

Now we have the ninth F class and they had a nice name.

They called their spacecraft TARAGINA which is latin meaning created out of the Earth.

It was a nice choice and good idea on the mission plan.

Next we have an eighth grade from St. Joseph school and nice detail there on the navigation instrument.

Really a lot of thought and naming all the different instruments that be used to help navigate from the Earth to the Moon.

Okay, now we have the Moon dusters.

That's a fifth grade at sunrise elementary.

They had some great artwork showing their rocket and their spacecraft, really nicely done.

Okay.

Now we have the fifth grade from commodore elementary school, Ms. shock's class.

I like the fact that they were going to have a super computer on the spacecraft to help track the position.

I think that's a good thing to carry along if you can manage it.

Now we have Ms. Bell's eighth grade science, Kristin and Tyson and they an interesting spacecraft name, the NUM2 K-9.

I like that one.

Another one from Ms. bell's eighth grade science with Emily, very use of the orbit and you see it there in the diagram.

The EL GALROW is the course the LCROSS is going the take when it goes to the Moon.

And finally we have Ms. Dunbar's class at SEIGERT elementary.

I thought they had a very nice NASA type of name.

In NASA it's common to name a project or spacecraft using several words and then you take the first letter of each of those word and it makes the name, called an acronym.

They have an acronym.

Their name is impacting Moon positioning adventure crater trajectory.

It spells impact.

They're thinking like NASA does when they name their spacecraft.

Everybody, I want to say great work and thanks for all of your thought and your effort and we'll look forward to talking with you more.

We're going to have some more detailed feedback up on the website in the next couple of weeks and also many of you did answer the mid-challenge question that we had, the problem that we called off course.

And your teachers actually have the solution to that problem in their teacher's guide, so check with them and they have the answer.

>> One of the things that was really very interesting to see in looking through these designs was that there were some -- certainly some differences in the navigational paths that you chose to get to the Moon.

That was very much the case, too, when we did the first navigation challenge and people had different routes to get from Hawaii to Rapa Nui and that was again the case here with the Moon.

And going through your designs they fell into basically three groups.

We had some missions that would go from the Earth and go to the Moon, some of you specified using a transfer orbit and then getting to the Moon going into lunar orbit before descending to the surface of the Moon.

We had another group of missions that did what we call direct to the Moon.

So going directly from the Earth to the Moon, not going into orbit around the Moon.

Just once you get there you have your impact, ka boom.

Then we have the third group that took what we call the LGARO apreach.

Lunar gravity assist and lunar return orbit.

Three different methods.

That's very good to see because, quite frankly, we have, with NASA missions, used all three methods and we certainly looked at all three of these methods when we were planning the LCROSS mission.

Now, with LCROSS we decided on the LGALRO approach.

Why is that?

Let's look at what happens when we would go into lunar orbit before descending to the surface.

So if you have a spacecraft that is in lunar orbit, it is going in a circle around the Moon and it is essentially moving, as you can see, parallel to the surface of the Moon as it goes around.

Now, it turns out when you fire the engines on your rocket to descend toward the surface of the Moon, what happens is that means that instead of just dropping right down to the surface of the Moon, what happens is you just make your orbit into a smaller circle and the more you fire your engines to lower yourself, what happens is you just get a lower and lower circle around the Moon.

>> But the direction of your motion is still parallel to the surface.

>> That's right.

You're still going to be going parallel.

Now, our first adventure at impacting the south pole of the Moon which happened with the lunar prospector did exactly this.

What some of you proposed is what happened with the lunar prospecting mission.

As we got lower and lower we were going parallel with the surface.

When we got low enough instead of coming in straight like this we came skitering along the surface.

>> The speed of the impact, the downward part of the speed was not that big.

>> That meant that we didn't have probably the most efficient means of excavating.

Those of you who participated in our very first challenge remember that we looked at that whole idea of angle of entrance.

How steep you come in and how effective that is.

Now, another option is the what we call direct to the Moon.

So if Rebecca is the Earth and we're coming from the Earth to the Moon and want an impact near the equator that works well.

You come in straight and hit at a nice straight angle.

If you're coming from the Earth toward the pole of the Moon look what happens.

You end up coming in almost parallel to the surface.

Again, that's probably not the best way to do excavation.

So with the LGALRO what we ended up doing is you do a fly-by of the Moon and use the Moon's gravity to sling you into a very steep orbit up out of the plane of the Moon's orbit and it goes around.

We'll take a look at this.

We have good pictures of this later on.

But the result is that when the spacecraft meets up with the Moon again, it is going to be coming in at a very steep angle relative to the Moon's pole.

That's why we chose that for the LCROSS mission.

It is important to keep in mind that isn't the only way to get to the Moon.

That isn't the only right answer.

The LRO mission, the launching along with LCROSS is going to be going into lunar orbit.

The critical thing to keep in mind here is that the two missions are studying the Moon in a different way.

LCROSS is going to be impacting the pole of the Moon whereas LRO will go into orbit around the Moon and map it.

And so because they have different tasks, because they're doing their science in different ways, their paths in getting to the Moon are different.

And if there is one real key learning to come out of this whole study that you've just done it's just that, as you design a mission and you look at how you are going to be studying it, the Moon, or Mars, what you are doing, the task that you are doing is very, very, very closely tied to the path that you take to get there.

As you design the mission, the path that you design is very, very, very much a part of what you are doing when you get there.

>> Brian, why don't you mention just a few of the instruments that LCROSS will actually have in helping it follow that path for staying on its course.

>> We talked about celestial navigation earlier.

We talked about the deep space network earlier.

The deep space network is going to be a very critical part of our navigation and making sure that we are on course and moving the right direction.

A very exciting part of that is that we have students in grade school through high school who will actually be using one of the big deep space network dishes to help monitor the health and status of our spacecraft as it is in flight.

But also on board the spacecraft to help with attitude control, we have a number of instruments that go back to what we had talked about earlier and let's see, I don't think we can quite see it here but there is -- you can see sticking right off the edge, maybe there is a little bit of a thing sticking down here, this is a star tracker.

We also have Sun sensors located around various parts of the spacecraft.

And these are used to make sure that we are keeping our attitudinal control correct so that we're pointing in the right direction.

That's a key factor as you're traveling.

It is not just where you are, the direction you're going, but also making sure that the antennas are pointing to the Earth to maintain communication, making sure this big solar power unit here is pointed at the Sun because while we need that in order to keep the spacecraft alive.

So attitude control is very important.

We're using the positions of the stars and Sun to help us do that.

>> Very nice.

It might be an interesting point to show our audience that on this model, the LCROSS spacecraft itself is actually a pretty ingenious design.

Brian, would you like to give the short explanation of what the LCROSS is made of and how that came to be?

>> Real quick here.

We're launching again with the lunar reconnaissance orbiter, it came along first.

But because we are going to be flying on an Atlas V rocket, it turns out we had some extra carrying capacity.

And so that was the Genesis of the LCROSS mission.

So the LRO would actually sit on top.

So here is the center upper stage of our Moon rocket.

Here is the LCROSS probe itself and then you have LRO that sits on top.

And LCROSS is occupying a place that is commonly called a payload adapter ring.

That payload adapter ring sits between the upper stage and your main payload that you're taking into space.

That's been something that has been on a number of these space crafts and instead of designing something completely brand-new for a spacecraft, the engineers at Northrup Grumman came up with an idea of using the payload adapter ring as the center of our spacecraft.

It is already going up there.

We've already got that made.

It's been certified to fly.

Let's use that payload adapter ring as the central piece of our spacecraft.

Then we put a fuel tank in the center.

You mount your instrumentation around the edge, put some thrusters and you're ready to go.

>> You have a spacecraft.

>> A very neat design.

>> LRO, when it goes into space on top of that, won't it?

>> Exactly.

>> Very nice.

Okay, well, before we get an update on the LCROSS mission are there any other final comments or suggestions that we should offer to our groups regarding their navigation plans?

>> You know, everybody thought carefully about it and there were a couple of places where, you know, they had some ideas that maybe don't quite work with the real world constraints that we all have to deal with in the space business.

We'll give a little bit more detail on that as we put a bit more detailed feedback on the website but this is meant to be a learning experience.

It is meant to get you guys to all be creative and put your ideas out there and it's not the end of the world if you have an idea that isn't 100% right.

The idea is that you take part in it and you have fun doing it and everybody did that.

We're very happy about that.

>> That's a very good point because that's not just something that happens in your classroom.

That happens in real life.

If you take a look at the original proposed design of pretty much any space mission and then you end up looking at what it ends up looking like at the very end, you'll see that there oftentimes are some fairly significant changes.

As you go along you realize that wow, what we initially thought maybe isn't really the best way to do it.

And so it really is just like it has been for you and it is for the scientists and engineers here, it is a learning process.

>> Excellent, yeah, I think you've hit the right word.

It is definitely a process, not just a single, straight forward answer.

So let's hear a little bit about where the LCROSS mission is and how the students in our audience can continue to participate.

>> Very good, thank you.

We're at a very exciting time.

We're talking to you now in May.

And just next month we are expecting to have something very interesting happening down at the Cape.

We're planning to launch, finally, this is great.

This is exciting.

That's one of the more fun parts of a mission, that launch is pretty neat to watch.

And we'll make sure you get the chance to do so.

Let's talk about what is happening.

The next slide, please.

So how are we going to launch?

We're going to use an Atlas V rocket.

The Atlas family of rockets have been around for a long time as you may get by the name, this is the fifth generation of the Atlas rockets.

Early Atlas rockets were used back in the mercury days when astronauts like John Glenn went into orbit.

The NASA uses of the Atlas have continued since then and with the Atlas V rocket we've sent spacecraft such as the Mars Reconnaissance Orbiter to Mars and the new horizons mission to Pluto and beyond to the KYPER belt.

This is a rocket with a fair amount of history.

Where are we launching from?

We are launching from space launch complex 41 at Cape Canaveral in Florida.

And this again is a fairly historic place.

A lot of exploration has gone from this launch pad, the Helios probes to the Sun were launched from there.

The Viking probes to Mars.

>> First landings on Mars, very exciting.

>> Neat stuff.

Of course, the Voyager planetary fly by and deep space probes and the Mars Reconnaissance Orbiter as well as the new horizons spacecraft to Pluto and the KYPER belt.

A lot has happened at this launch complex and we're looking forward to another exciting launch.

>> I like the fact we're taking off from a launch pad that has had so much exploration associated with it.

This mission is a very important milestone in the exploration of the Moon.

>> So what's happening down there?

Well, the Atlas V first stage has arrived.

It comes in on a large cargo aircraft and so that has already happened.

Next.

And it has been taken to a big tall building right next to the launch complex.

This building is called the vertical integration facility.

And here you see a picture of an Atlas V first stage booster arrived at the vertical integration facility.

>> It comes in on its side.

It comes in on a kind of a truck on its side and then later they will turn it vertical.

>> In fact, let's see a picture of that.

Here it is being lifted up into the vertical position inside this vertical integration facility is where the different components of the spacecraft get stacked.

They get stacked in a vertical position.

So the first thing is we're lifting this first stage into the vertical position.

Go ahead.

There you can see it in the upright position.

Next.

Next comes the center upper stage.

>> I want to point out, look at the size of the rocket compared to the people.

It really gives you an idea of how big these rockets are.

>> You can see the walkways around the rocket in the background there and so now the upper stage gets lifted up on top of the first stage.

That has now happened.

Go ahead.

Then what's going to happen, hasn't happened yet, will be that the top payload, that's LCROSS and LRO, will then get stacked on top of the centaur.

That is going to be happening very soon.

Once all that is done and everything is hooked up and fueled and ready to go, then the whole stack rolls out on a train track from the vertical integration facility out to the launch pad.

And it is surrounded by a series of vans and trailers that provide electricity and communications and all the necessary things that the spacecraft needs to stay alive as it rolls out to the launch pad.

>> That's a beautiful thing to look at, isn't it?

>> We're looking forward to this.

So next month in June we are going to have a launch.

That means that we are looking forward to an October impact.

And we will be targeting the south pole of the Moon.

And again, the route we're taking to get there is called LGALRO.

Lunar gravity assist, we do the Moon's gravity to swing us into the series of large looping orbits around the Moon's system.

38 days just to make one of those loops.

We'll make several of them.

The idea being when we meet up with the Moon again, we'll do so at that nice, steep angle relatively to the pole.

Continue.

So what else is going to be happening during this time?

Well, some really exciting stuff.

Again as we mentioned students are going to actually be helping us with this mission.

They are going to be using one of the giant 34-meter dishes, DSS13 dish at gold stone.

This is through our partnership with the Goldstone Apple Valley radio telescope program run by the Lewis center for educational research.

These students are going to be monitoring our spacecraft in flight.

Very exciting opportunity.

But then toward the end of the mission, we have that impact.

And that is going to be an especially exciting time.

One of the things that we think is that that impact may well be visible in amateur telescopes.

So we're encouraging people with backyard telescopes and tools with telescopes to get out there and participate.

To observe the impact.

If you're capable of taking pictures through your telescope, please take pictures of the south pole of the Moon when we do our impact.

If you can get images of the impact cloud, we would love to see them.

The more data we have, the better our understanding will be.

So this is an opportunity to actually participate in the science of the mission.

>> Of course, not everybody in the country will have a view of the Moon at the time of the impact, so you'll need to -- where will they find out about whether they can actually see the impact from their location?

>> That's a very good point.

The exact timing of the impact is going to be critical.

Will it be in the sky, will it be during the night for your particular area?

And go to www.NASA.gov/LCROSS to find out.

After we've launched we'll be able to keep you posted on some exact times.

Now, even if the impact is not visible in your sky, that don't mean you're going to miss it.

Because as is the case with the launch and will be the case of the impact, you can watch it either on TV if you have NASA TV, tune in there, and if you don't, go to www.NASA.gov and you can see what is an NASA TV streamed to your computer.

>> In fact, we'll be having a little sort of web event of our own that you can tune into to kind of help you get prepared and all excited about the impact and then we'll be standing by as the impact takes place.

>> So please keep your eyes open.

This is going to be fun.

>> For the exciting things going on this summer we certainly have the LCROSS mission that we'll be launching Andy, what else do we have happening this summer?

>> This summer is the 40th anniversary of the very first Moon landing with people, Apollo 11.

It will be a time when we're looking back at the really amazing and momentous explorations that took place when we first sent humans to the Moon back in the late 60s, early 70s and was a tremendous achievement for the technology of space exploration, a tremendous human adventure for the people who got to go to the Moon and tell us what that experience was like and also for all the people that worked on the project to be part of that was tremendously exciting.

It told us so much about the Moon that we never knew before.

In fact, from the Apollo missions we've been able to piece together the idea of how the Moon was actually created.

We think there was a gigantic impact that struck the Earth and blasted stuff out of the young Earth very shortly after it was formed and that that debris went into space and eventually came together to form the Moon.

So all of this is part of the detective work of science that we were able to do because of the information and the rock samples and the other data that was brought back from the Apollo missions.

So we're looking back on a historic time for lunar exploration, even as we look ahead and we take part in this new example of lunar exploration.

>> For those of you who happen to be in the northern California area on Sunday, July 19th, we'll be having our MoonFest event here at NASA Ames.

And what we will be doing is we will be celebrating the 40th anniversary of the Apollo mission, first landing on the Moon, as well as the upcoming LCROSS impact and then future exploration of the Moon.

We're doing this in conjunction with the NASA lunar science institute.

So the LCROSS mission and NASA lunar science institute are getting together to bring you a day of exploring NASA lunar exploration here at NASA Ames.

You're welcome to join us.

>> I might just insert here, Brian, if they want to see the invitation they can go to quest.nasa.gov and there is a full-sized invitation there for them.

>> Very good.

Thank you, Linda.

>> So in speaking of the Moon, in case you're not aware we have an exciting drawing associated with this space navigation challenge.

For those of you whose teacher filled out our preand post surveys.

We'll talk about them before we sign off today.

For those in the classes who also submitted a navigation plan we'll enter your class's name into a drawing for an actual slice of a Moon rock.

Let's take a look at that slice of Moon rock.

Brian, can you tell us a little bit about this sample?

>> Yes.

So this is a piece of actual rock from the Moon.

It is basically a kind of lava rock.

But it comes to us in the form of a meteorite.

This was not brought back to us by the Apollo astronauts.

The Moon is covered with crater and has gotten battered for millions of years.

A number of those impacts blow pieces of the Moon off the surface and out into space.

And some of those pieces of the Moon make their way to the Earth and actually land here on the Earth in the form of lunar meteorites.

This is an example of just such a thing.

This is actually what is called the NWA4734 lunar meteorite.

How is that for an exciting name?

NWA means northwest Africa.

That's where it was recovered.

It was recovered in the deserts of Morocco and found in October of 2006.

This is again an actual piece of the Moon that those people who participate and whose teachers fill out our final evaluation will be able to become part of the drawing for this.

Now, in addition because the fact of the matter is we got some really great participation here.

And so we decided, you know, we need some additional prizes here.

So in addition to the Moon rock, we have two other samples that we are going to be entering into a drawing and these are tektites.

>> Tektites were a mystery for scientists for a long time and as we learn more about impacts and the violence that impacts produce, they create so much energy that they actually blast stuff off the ground and sometimes if it's a really big impact, it can actually blast material from the surface of a planet into space.

And we think that tektites are examples of that that happened by impact on the Earth long ago in geologic history when an asteroid struck the Earth with so much force that some of the material, some of the debris that was ejected, probably in molten form, in liquid form was heated so much and melted.

Went into space, may have gone around the Earth a couple of times or maybe not quite a full orbit but did go into space and re-entered the Earth's atmosphere and fell back on the Earth.

So we think that tektites are ejected material from huge impacts that happened on the Earth.

>> We have two of those that will be in our drawing, too.

Three lucky classrooms are going to come out with some pretty interesting material to have in their classroom.

>> Space rocks

>> Indeed.

>> Those will be great.

That will be a really neat asset to any classroom.

So we're going to move on to the Q and A portion of your webcast.

Your chance to ask questions about space travel, navigation, the Moon, what have you.

Let's begin.

Linda, what do we have so far in our chatroom?

>> We have quite a few, actually.

Andre from our romaineian school writes over the years is it possible to create artificial gravitation on the Moon?

If we can, what instruments do we have to improve and due to what theory are we able to do this?

And if not, on what things should we base our research?

>> Well, you know, it's not necessary to create artificial gravity on the Moon because the Moon already has gravity.

It is 1/6 of what the gravity is here, so -- but that's enough to keep things down on the surface.

And, in fact, it is actually a lot of fun to go to the Moon because the gravity is only 1/6 of what it is here and everything weighs 1/6 of what it would on Earth.

I don't see a need to create artificial gravity.

I don't know how you would do that short of adding more stuff to the Moon.

>> If you were going to do an experiment where you needed more than the 1/6 gravity on the Moon, then you would probably do something similar to what we've done on a number of our orbital missions is you would employ a centrifuge.

By spinning something around in a circle, you can create that force that will replicate the varying amount of gravity.

>> And actually there is a really interesting question that we're going to need to solve if we're going to have people living on other planets.

And that is, how much gravity is actually necessary to keep a person healthy?

We know that if a person is in weightlessness for very long periods of time that they lose minerals from their bones, they lose strength from their muscles and so forth that can harm the immune system on the body.

So we want to be able to expose astronauts to a certain amount of gravity either by spinning the spacecraft as it travels through space or something like that.

But we don't know how much gravity is required to allow the body to do the normal things that it does on Earth.

And one way that we might find that out is to go to a place like the Moon, study how people react to 1/6 gravity and then maybe as Brian is saying we could use a centrifuge to increase the gravity very slightly, maybe while they sleep and monitor their body functions while they're sleeping and what happens to their bones and their muscles, and so the Moon might end up being part of a laboratory that helps us figure that question out.

>> Okay.

A question from Christian.

What else besides water can be extracted from the lunar soil?

>> Great question.

There are quite a few things.

One thing that we would, of course, be very interested in is hydrogen.

Now, hydrogen, if we do find deposits of water ice on the Moon that is a great source of hydrogen right there but hydrogen also is probably enriching lunar soil in the form of the solar wind.

We think of it sounds funny a wind in space.

There is this wind of hydrogen particles and atoms coming off the Sun and embedding themselves into the soil of the Moon.

>> It is not a wind that is strong enough to help your rocket navigate.

I won't say who suggested that one but you have to rethink that because the solar wind is not a real wind that you could use to steer your rocket.

Just wanted to throw that in there.

>> People are looking aren't looking at solar sails.

>> You're using light, not the solar wind.

The solar wind -- the Sun does pour out these sub atomic particles from all its solar flares and those particles go racing through space.

Because the Moon has no atmosphere there is nothing to stop those particles from hitting the Moon where they get trapped in the dust of the Moon.

So we think that hydrogen and other things from the Sun, we would find them mixed in with the lunar dust.

>> We also know that in some of the minerals on the surface of the Moon there is oxygen.

So if you really needed to extract oxygen in some way other than from water, you can do that by heating the rocks on the surface of the Moon to about 700 degrees Celsius.

>> Which you could do by focusing if you wanted to, you could focus sunlight with a mirror, the sunlight on the Moon is very strong and you could use a mirror to make the temperature high enough to do that.

>> We're also finding on the surface of the Moon that there are metals such as titanium.

There are a number of interesting potential resources on the Moon.

>> Lunar dust may turn out to be a building material all in itself.

There are people who have studied how you might use Moon dust to make a form of concrete that you could then build structures out of.

>> Okay.

Mrs. Purell's water seekers want to know if you find water on the Moon, how long will it be until humans live there or go there?

>> That is an excellent question.

That's actually a question that a lot of people are trying to answer right now.

And we're doing this by these early robotic missions to the Moon.

What we're doing is we're trying to learn more about the Moon.

It is really kind of funny, the Moon is so much closer to us than Mars is, but we know much more about the surface of Mars than we do about our own Moon.

That clearly has to change.

And so now a series of robotic spacecraft, LCROSS is one of them but then you have the lunar reconnaissance orbiter and you have spacecraft from other countries, too.

This has actually become a very exciting and busy time at the Moon lately.

For a number of years the Moon got to be a pretty lonely place after Apollo but that's changed right now.

Japan has a mission orbiting the Moon right now.

India has a mission.

China recently had a mission.

The European space agency recently had a mission and we're about to have two missions here.

So we are going to try and answer some really fundamental questions about the Moon that will help us to try and figure out what our next steps are going to be in terms of lunar exploration.

In doing so, we're talking with a lot of these other countries that are launching missions to the Moon.

We're sharing information and we're going to work together to answer these critical questions because again, it's in our own backyard but there is so much about the Moon that we just don't know right now.

>> And the Moon is really kind of a museum for the earliest history of the stole -- solar system.

There is no other world in the solar system that can tell us what the Moon can tell us about the earliest part of the solar system's history.

>> The nerdy Moon missioners have sort of a progressive question here.

How long did it take to arrange the LCROSS mission all the way from planning to building to implementing?

What will happen to the mission if you don't find water on the Moon?

And what will happen to the rocket -- what will happen to the rocket on the LCROSS mission if it misses the Moon completely?

>> Wow, well, we certainly hope that doesn't happen.

So a three-part question.

Let's try to take this in order.

How long did all of this take?

That's a really interesting story.

Because the LCROSS mission was first proposed in early 2006.

And it had to be ready for launch by October 28th of 2008.

That's not a lot of time and then you had to be able to fly the entire mission.

Basically, you know, it was a really short period of time.

>> It sounds like what do you mean, that's over two years?

Two years to design a mission?

Think of all the work you've just put into putting together your designs.

And there was a whole lot of design work but then you had a bunch of engineers in southern California who broke is spacecraft, they had to design and build the spacecraft.

Designers and engineers at Ames who designed and built the instruments that will study the plume.

You have a lot of people at Goddard space flight center and JPL who are helping to design trajectories.

You know from your own experience that trajectory is a really important part of the mission.

And then you have a lot of people at Kennedy Space Center who are putting together this whole process of getting this thing to launch.

That's a lot of work.

In just a little, you know, two, three years' time, wow, that's a very short time for a Moon mission.

The second part of the question was what happens if we don't find water?

And we get asked that a lot.

Does that mean the mission is a failure?

Absolutely not.

Again, what we just talked about there is so much about the Moon that we don't know.

Now, we've had some previous missions, lunar prospector and Clementine that there may -- want to emphasize that -- may be deposits of water ice at the poles of the Moon.

But different people look at that data in different ways.

Some people look at the data and say look at that, it's water.

And other people look at that and they go, I don't think so.

And it is a fundamental question.

As long as we're using this what we call remote sensing technology.

Using neutron spectrometers to look from a far distance, there are kinds of different ways to interpret the data.

>> Uncertainties.

>> What we really need to do is essentially get our hands wet, if you will, and so--

>> Or at least dirty.

>> Basically go in there and take what is at the bottom of these permanently shadowed craters, get it into the sunlight where we can see it and study it and see what's really there.

So we will be happy either way.

We'll be happy to be able to help answer that question.

So from our point of view, there is no bad data.

Now again, one thing that would be really bad is what happens if you miss the Moon?

Well, again, fortunately we have a really, really talented group of incredibly smart people here who are doing everything they can to make sure that we have the best chance possible to actually impact the Moon.

Now, I would say that our chances are looking pretty good.

If you look at some of the past missions to Mars, there have been some instances where some of the times you miss.

But Mars is a lot further away.

It is a remarkably hard target to get to.

That's one of the advantages of exploring an object that is essentially, in terms of space, in our own backyard.

So we are optimistic that we'll see something hitting the Moon come this October.

>> Very nice.

I did want to reiterate what you were pointing out, Brian, in the first part of the question that it does take a lot of different types of people to make a mission happen.

So we have the engineers who are helping design the rocket and the spacecraft, mounting all the instruments.

We have spectrometers, cameras, all sorts of things on board.

We also have the scientists who are going to be collecting that data and analyzing it.

Then we have project managers, people that have to manage the budget.

We have education, public outreach.

All sorts of people who are involved in a mission so keep that in mind.

Think about your own personal interest and the things that you like to do and more likely than not there is probably some connection to the types of jobs that are connected to a NASA mission.

>> We have artists working on this to help us visualize what is going to be happening.

>> Okay.

We have quite a few more questions and very little time so Allen's full throttle flyers wants to know.

Some of it has been answered.

How did the idea of LCROSS mission come about.

What would happen if the spacecraft went off course and hit an asteroid, and what does a gravitational slingshot do?

>> Three good questions.

How did it come about?

He came about again because the LRO mission, which had been planned for quite some time, got its launch vehicle changed and upgraded to the Atlas V.

The Atlas V has additional carrying capacity.

So now here is this extra room and power on a launch vehicle that is going to the Moon and rather than just have that go to waste, NASA said here is this great opportunity.

If you can come up with a design for a mission that meets these certain specifications for weight limits and also specifications for budget limits, then you have the chance of going to the Moon.

So everybody went into mad proposal writing mode and NASA had a competition and LCROSS ended up winning the competition.

Second part of the question was what happens if we hit an asteroid?

Well, that would be pretty darn amazing.

Missing the Moon would be a really bad thing but if you're going to miss the Moon and end up hitting an asteroid we'll take that as a consolation prize.

>> We'd settle for that.

>> That really fortunately seems very unlikely.

Again, the Moon is bigger.

>> Closer

>> A bigger target than any of the asteroids anywhere near the Earth right now and as Andy says, it is closer.

>> Occasionally there are asteroids that come whizzing by closer to us than the Moon but hitting one, if you're trying to hit the Moon you won't hit an asteroid.

>> So we consider that to be a very unlikely scenario.

>> I'm looking at several different questions that ask how long did it take you to build the rocket or how long did it take you to put together the LCROSS mission and I think it's been addressed.

But you might want to talk about the -- they want to know whether or not it's been worth it.

>> Has it been worth it?

Absolutely.

First of all, from a number of points of view.

From one point of view in terms of the science that we expect to gain from the mission.

We will learn more about the Moon but also more about the neighborhood and the solar system in which we live.

The Earth's environment doesn't end with our atmosphere.

We live in a part of the solar system and the conditions in that part of the solar system can have a profound effect on the Earth.

And so we want to know more about what is happening here in the inner solar system and where can water form and continue to exist?

And where did that water come from?

Also the LCROSS mission has been very beneficial in terms of looking at a new way of designing and building spacecraft.

Doing something in a very, very short time frame.

This is kind of a new way of looking at it.

And we've learned a lot from doing so.

So yeah, it's been worth it from a number of points of view.

>> That's great.

We have more questions but I'll remind you that Andy said there will be more information on the website as we -- in the next couple of weeks.

I think we're going to have to wrap up now because we're coming to the end of the hour, Rebecca.

>> Okay.

Well, as Linda said, our webcast is going to draw to a close, so thank you, Linda, very much for fielding our questions and before we do sign off I do want to thank Brian and Andy for joining us today and give you a chance to offer any final comments or suggestions to our audience.

>> I hope we've got some future Moon explorers that will result from all of this participation in LCROSS.

>> Absolutely.

This has been a very, very exciting and encouraging thing seeing your designs.

I think that the future of human space exploration is looking pretty bright as long as we have bright, enthusiastic people like you leading our way into the future.

Thank you very much.

>> And thank you to those of you who have tuned in live with us today and for those of you who submitted the questions, it's been fun working with you and receiving your navigation plans and your ideas.

A special note to our teachers, we do look forward to getting feedback from you in regard to how this challenge worked in your classroom.

There is going to be a post challenge evaluation posted on the quest website.

Please do go to that link and fill out the post evaluation to us.

It's important to us and helps us plan future challenges and improve them.

Remember there is the bonus of getting your name entered into a drawing for the Moon samples.

So we hope that you'll take the five or ten minutes it takes to fill out the post evaluation survey.

That concludes our webcast.

Thank you again for joining us.

We hope that you will participate in another Quest Challenge.

So always stay tuned to the website and see what's coming up next.

And enjoy -- we hope that you will continue to follow along with the LCROSS mission and keep tabs on the progress of that as well.

So thanks again.