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MER-B Webcast - Launch Director & Mars Rover
 
Question and Answer Board

Stephanie from Edmonton, Canada
Since the only cameras are on the rover itself, will you have any way of showing what the rover looks like roaming on Mars? (i.e., will you be using digital animation to give the public a feel for what the rovers look like on the surface?)
Steve Squyres:
Well, there are a couple ways we can do that. One thing, of course, is that the rover can actually take pictures of itself. Those cameras are mounted high on the mast and if they look down or around they can get a very good view of the solar arrays. We've also got some nice cameras out in front that will actually show the arm nicely as it deploys. So we will actually be able to do a fairly good job of photographing the rover ourselves. We probably will try to do some digital animations as well. We have made some animations already of what we think the rover is going to look like as it drives around Mars, and I anticipate once we get real Mars data we will continue with that.
Stephanie from Edmonton, Canada
When Opportunity lands at Meridiani Planum, what will you do if it lands far away from the hematite? If you find olivine at either of the two rover sites, would that change the scientists' theories about the sites?
Steve Squyres:
Well, with respect to what we would do if we found we weren't near hematite, that's the reason why we have wheels. There is definitely a possibility that there will be no hematite bearing rocks that are within easy and immediate reach, but we have got a lot of ability to drive this rover. We can drive for hundreds of meters across the surface if we need to, and so we can look off into the distance using our instruments, find where we think hematite bearing minerals are and then actually drive over to them. With respect to olivine, actually I don't think that will change things too much. Olivine is a mineral that is found in a lot of very common rocks. Basalt, which is a common igneous rock, has olivine in it. And we expect a lot of that stuff to be there. The question is not what are the main rocks, the volcanic rocks and so forth; the question is what are the trace minerals, the minerals that are present in lower abundances, and how much of those there are, because those are the ones that are more likely to tell us about water.
Stephanie from Edmonton, Canada
What is the difference between Terra Meridiani and Meridiani Planum? What is the correct name of the landing site?
Steve Squyres:
The correct name of the landing site is Meridiani Planum. Terra Meridiani is an old name; it's one that's been around since very early in the days of Mars exploration and it refers to the whole broad Meridiani region. Meridiani got its name from the fact that the zero degree line of longitude, the meridian on Mars, runs right through that location. So that big area near the equator is called Terra Meridiani - the specific plateau or plane, which Latin for plane is planum, that we're landing on - is called Meridiani Planum. So that is the right name for the landing site.
Stephanie from Edmonton, Canada
During the launch of MER-A, at about T+15 through to T+30 seconds, there appeared to be a splattering of a liquid onto the onboard camera. Was that bychance the rocket going through the clouds?
Omar Baez:
No, Stephanie. What we have is, if you notice the Delta II rocket before we tank it, it is actually a nice teal blue color. When we tank it, it turns a nice white frosty color, and there's a reason for that. We load the first stage up with liquid oxygen, which is at minus 300 degrees Fahrenheit, and we form a frost coating over the first stage, or ice actually. If you look at the tape when it rolls initially, right at launch, you will notice a lot of ice coming off. What's going on in that first couple of seconds is, as we're rising, some of that frost on the launch tank is melting off and that is the precipitation you see forming on the lens of the camera as it came over the fairing on the first stage camera.
Richard from Arcadia, Florida
Will using the RAT cause any problem with dust on camera lens or instruments?
Steve Squyres:
We're pretty confident that it won't. This was something that we thought about a lot as we were designing this payload. In fact, the first version of the RAT actually had what we called a dust skirt. There was a fabric skirt all the way around the outside of it, and the idea of that was to prevent pieces of dust and particles from getting thrown off by the RAT. What we found out, though, was that when we actually tested it, what that did was it kept so much of the dust inside that the dust would fall back into the hole and we couldn't see what we were looking at. So what we did was, we did a bunch of tests where we actually took a rock abrasion tool, the real instrument itself, put it into a vacuum chamber, pumped most of the air out of it, and took it down to the kind of atmospheric pressure we'll have on Mars, and ran it. What we found was the cuttings, as we call them, flew in directions that would not impact the camera and so we really feel pretty safe that we will be able to use that. So we took the skirt off and we're going to let the particles fly.
Peter from Leipzig
Is this a hope for a future manned crew to Mars? I hope that and I think it's the next step into space for mankind.
Omar Baez:
Peter, absolutely this is a future hope for a manned crew to Mars, although I don't think it's the next step. For me to stay in business, we've got to launch a couple more of these robotic missions, but it sure is one of the steps in getting there, to make sure that we are going for the right reasons, and it's one of the many steps. There are other things we want to do out there past this geological mission and this is one of those steps in getting there.
Rich from Elk Grove, Illinois
What steps are in place to handle a rover that does not respond correctly to the commands it is given? Is there a possibility of the rover doing its 'own thing'?
Steve Squyres:
Well, certainly we do have situations where the rover does not respond in the way that we expect it to when we send it a command. The rover is basically run by a computer. One thing you learn about computers is they don't always do what you expect them to; they do exactly what you ask them to, even if what you asked them to do is wrong. What we have done, though, is we've put into the rover at very fundamental level in the software, what we call fault protection. There are circumstances where we can accidentally ask the rover to do something that would hurt itself and the rover will reject that command. The rover is, we found in some instances during the testing, a bit smarter than we are. So what we have done is set it up so that if there is an invalid command that is accidentally sent, despite many checks and balances that we have along the way, it will be rejected by the rover and that is something that we have tested very extensively. So I feel pretty confident that if we tell it to do something bad it won't do that. As far as doing its own thing, the software really isn't set up to allow it to do that, fortunately, so that is not something we worry about.

Host:
I have heard you mention in another presentation I saw that it basically tells you, OK; I'm here, now what?

Steve Squyres:
Right, and in fact, it also has built into it the ability to know when it gets into trouble. The rover, you don't want it to tip over for example, so one of things it's got is its got the ability to tell which way is up and which way is down. If the rover ever got tilted more than about 45 to 50 degrees it actually could flip over which obviously would be a bad thing. So what we've done is we've built into the capability that if it gets to a rock and it ever senses that it's tipped as much as 30 degrees, which is still far short of the danger zone, at 30 degrees it will just freeze. It will just absolutely stop, take a set of pictures, and send the pictures back and say help me, I'm in trouble and what do I do. So it knows when to quit.
David from Winter Springs
What is your spaceship's name going to be?
Omar Baez
The spaceship's name is going to be Opportunity, and this was one of the names that a little girl came up with. The first one being Spirit, the second one being Opportunity.
Russ from Yuba City, California
Will JPL/NASA labs be monitoring both rovers at the same time? Will the public be able to see both rovers working at the same time? Split screen stuff?
Steve Squyres:
Well, we will certainly monitor both rovers at every chance that we get. But the thing you have to realize is that the two landing sites that we have chosen are on opposite sides of Mars from one another, they are 180 degrees apart on the planet. And so when one of them is visible from the earth, the other one is out of sight on the other side of the planet. When one of them is in sunshine and the rover is active, the other one is in darkness and the rover is asleep. So even though they will both be on Mars simultaneously, they're never both active at the same time, just because they are on different parts of the planet.
Peter from Basel, Switzerland
When Spirit and Opportunity land on Mars, how long will we need to wait for the first photo?
Steve Squyres:
It takes a little while, because when the rover first touches down, there are a bunch of things that have to happen. The lander has to open up, the petals have to open out on the solar array, and it takes a period of time before the spacecraft is really to the point where it's able to start even doing any picture taking. So it's going to be at least, I think, 24 hours or so after we touch down before we are actually going to see pictures.
Mirtha from Manahawkin
Do you think there are people up there?
Omar Baez:
Mirtha from Manahawkin, no, I don't think that there are people up there. What we are looking for is really, are there signs of water, and what has the water done to that planet, and in what quantities and so forth. And maybe looking back in retrospect, is there something we can do to support our planet a little bit longer. What went wrong on Mars? There's evidence of water there and it happened a long, long time ago. There's an atmosphere there, it's a colder climate, but has similar days to us and it has an atmosphere. So what we are looking for is how long was the water there, how much of it was there, and maybe take some of that information and apply it here and hopefully the earth will sustain much more than Mars did.
George from Concord
How long till the units arrive on Mars? And how long can the robots run on Mars? How long did the last robot stay active?
Steve Squyres:
Okay, it's going to take us about seven months to get to Mars. One rover is on the way right now and the second one is about to be launched. They will arrive at Mars the 4th and 25th of January of next year. As for how long they are going to last, it's a good question. The design lifetime, as we call it, is 90 Martian days or 90 sols, which is about three months. That doesn't mean that the wheels are going to fall off when the sun comes up on the morning of the 91st sol. What it means is, basically, that's when the warranty expires. We have designed these vehicles to last at least that long. How long they will actually survive depends on a bunch of factors. It depends on the Martian weather. It depends on how much dust falls on the solar arrays, that's one of the things that will limit the lifetime of the vehicle. But we think it will be at least three months and maybe a good deal more.

Host:
Now when you mention warranty is that similar to, or are you talking about the battery?

Steve Squyres:
I'm talking about every aspect of the vehicle. If you look at this rover, it's an incredibly complicated machine. It's got a lot of moving parts, it's got a computer, I'ts got batteries, it's got solar cells, it's got these wheels. Every one of those things can eventually wear out as a consequence of lots of use. And so you've got to make sure that every part of it is going to be able to withstand at least 90 days of operations.
Jennifer from Edmonton, Canada
Are there any specific geological interests about the landing sites chosen for the MER rovers? Is there anything that would make you suspect that these landing sites would contain more relative information than another site?
Steve Squyres:
Absolutely, we started off with 185 different possible landing sites for this mission, a whole bunch of them. All of those were landing sites that this vehicle was, in principle, capable of getting to. Even when we looked at them carefully and started throwing away the ones that for whatever reason looked too unsafe, like the vehicle couldn't go there, we still had many sites available to us that were safe enough and so we could pick the ones that had the best science. So what we have done is try to pick two sites that are not only safe enough to land at but also have a lot of scientific interest. Mars varies a lot from place to place and we have tried to pick two places that have a very good chance that there were once warmer and wetter conditions there.
Jennifer from Edmonton, Canada
How is the process by which the MER Rovers will be traveling to Mars (trajectory speed, etc.) unique between the two rovers? How is it different from the Mars Pathfinder rover?
Omar Baez:
Jennifer, there is not much difference between Pathfinder and the MER-A and the MER-B missions. But I will tell you the slight differences are the timing of events. As I told you earlier, we're using the Delta II Heavy vehicle for the MER-B mission. The later we wait, the more energy it takes to get into an Earth escape and a Mars impact type trajectory. So we are going a little bit later than MER-A, therefore it takes a little bit more energy. If I looked at the relative speeds between MER-A and MER-B, MER-A when we left it - or when we separated it from its third stage - was traveling at approximately 23,042 miles an hour. MER-B should be separated at 23,135 miles an hour, a difference of about 90 miles an hour. But these events take place at different times. For the MER-A mission, we achieved this escape velocity shortly after the second stage was done with its mission out over Africa and over into the Indian Ocean. This mission takes a little bit longer. As it leaves here from the Cape, we have approximately a 70-minute coast phase, and we do our escape out over the Pacific Islands of Kwajalein, the atolls out there in Hawaii, so we're taking a little bit longer and we're going a little bit faster to catch up with what MER-A is already doing.
Jennifer from Edmonton, Canada
If siginificant geological findings do occur (i.e. evidence that Mars could have supported life) will another rover be sent to investigate this and bring back rock samples for further analysis on Earth? What are the options if something like this is found?
Steve Squyres:
Well, that's a great question, and I really hope that's exactly that happens. Your question is dead on; what we are trying to do with MER is to determine whether or not these landing places were places that could once have supported life. If we find that Gustav Crater or Meridiani Planum is in fact the place that looks like it was warm, and wet - inhabitable - what I would love to see happen is to go back there with another vehicle, bring some rocks back and get them to the best laboratories on Earth and really check them out in detail. Whether or not that's going to happen certainly depends on what we find. It's a process of continual exploration and learning.
Richard from Melbourne, Florida
I have just recently read that the mission is being postponed for several more days because of an issue with a band of cork insulation on the Delta launch vehicle. This seems to be such an odd choice for an insulation material on the spacecraft. Why is cork being used on the outside of the launch vehicle in such a humid environment with such strong sunlight as well? Thank you.
Omar Baez:
This is a good question, Richard. I'll tell you, the simple thing is, we use cork all over this vehicle. It's a readily available natural material and it is easily shaped to round surfaces such as the Delta II or the cylindrical. And it is very forgiving. I talked earlier about the tank seeing temperatures from ambient - about 90 degrees - and when we load LOX onboard, it goes to minus 300 degrees. So things made of aluminum and such, which the tank is made of, shrinks. So what we need is an insulation barrier of some kind that can also take the shrinking and expansion and be flexible enough to lift through this. I think that cork is one of those materials that we fell in love with early in the space program and are using it ever since. It's a material that is very natural; you don't have to wear special equipment to apply it. It's very easy to cut and shape. And yes, it does have its drawbacks; one being, yes, it loves to absorb moisture and it doesn't do very well in sunlight. But, then again, we don't like to keep our rockets out in the rain and we don't like to keep it out in the sunshine. That's why we have a tower around it. The Delta II that we are going to use for the MER-B mission just stayed out there a little bit longer than we intended it to.
David from Berkeley
What improvements have been made in the rechargeable batteries (since Pathfinder) to insure that electrical power lasts longer?
Steve Squyres:
Well, there are two things that are different. One is that we are using lithium ion battery technology; it's the best battery technology that's available these days. It is the same stuff that is used in highly sophisticated applications, like laptop computers. So we are really up with the state of the art on the batteries. The other is that we have much, much more capable, much more powerful solar arrays to recharge the batteries every night. So each day, during the daytime we top off the batteries to a pretty substantial load, and so there is a lot of power to keep the vehicle alive overnight.
Klaus from Aabybro, Denmark
During this long trip to Mars, what is the top speed the craft will achieve? Thank you for your time!
Omar Baez:
At the point that we separate the third stage from the MER-B spacecraft, we're looking at about 333,932 feet per second. If I convert that to miles an hour, that's 23,135 miles an hour. There'll be some additions to that with the trajectory control maneuvers, TCMs, but those are very small, they're on the order of 4 to 12 feet per second.
 
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