Live Forum with Ashley Stroupe

[TariqJMalik]

Hello Ashley,

Thanks so much for taking time to answer questions on SPACE.com from our readers. One question I have always wondered about is if Spirit and Opportunity handle differently when you command them from Earth. Or is it more like once you've driven one rover, you've driven them all. Does each have their own unique personality?

And do you have a favorite?

Thanks,

Tariq

[silylene]

Thanks, as you know, many of us are following Spirit, and hoping it can continue its travels again soon. From the ground testing, are you hinting of positive news for methods freeing a rover stuck in a similar manner?

[AshleyStroupe]

Crab driving is when we steer all the steerable wheels (front and back) to the same angle and then drive, hoping to get some sideways motion. This is one of our standard driving approaches. Conventional approaches are those tools we typically use to drive Spirit: driving forward or backward, arcs, turns in place, and crabbing. We're going to probably start with driving forward, probably crabbing uphill to try to move away from the white fluffy soil.

[AshleyStroupe]

Do you know roughly what percentage of the data returned from the rovers is relayed through Mars Odyssey and MRO and what percentage is sent directly to Earth? I would think the latency of using an orbiter as a relay would be very substantial since you have to wait until it happens to pass overhead. I seem to remember this being a topic of discussion in the early missions press conferences.

Almost all of the data comes through Mars Odyssey. I don't know the actual percentage. The latency is slight (the orbits are fairly fast, about 2 hours), but the orbiters have much larger antennas and can send back data at a much higher bandwidth. Without that it would be very hard to get pictures dow.

[tofu702]

From the technical perspective, what lessons has the team learned from MER? If you could change something about the design of the rovers what would it be? Will this influence the design of future planetary rovers like Mars Science Laboratory?

[AshleyStroupe]

Hello Ashley,

Thanks so much for taking time to answer questions on SPACE.com from our readers. One question I have always wondered about is if Spirit and Opportunity handle differently when you command them from Earth. Or is it more like once you've driven one rover, you've driven them all. Does each have their own unique personality?

And do you have a favorite?

Thanks,

Tariq

Actually the rovers do behave differently! Spirit and Opportunity are first in very different terrains, and so you have to drive them differently. Also, they have aged differently and have driven us to use very different strategies. We have to drive Spirit mostly backward to drag the broken right front wheel, and we have to drive Opportunity with the robotic arm out in front since one of the joints broke and we can't stow it anymore. So, it's definitely not "drive one, drive them all".
I do have a favorite - Spirit is my favorite, but I love Opportunity too!

[TariqJMalik]

Hi Ashley,

Just today, scientists announced finding signs of water ice at the bottom of young craters on Mars at lower latitudes than expected. Would it be possible, given Opportunity's experience with exploring inside craters, that the rover could hunt - and study - ice at the bottom of an enormous crater like Endeavor, when it arrives? Does it have the right tools for that kind of job?

Thanks!

Tariq Malik

[AshleyStroupe]

Thanks, as you know, many of us are following Spirit, and hoping it can continue its travels again soon. From the ground testing, are you hinting of positive news for methods freeing a rover stuck in a similar manner?

The ground testing is very difficult because we can't model things exactly as they are on Mars. Our testing is promising, and gives a lot of hope. But, Mars is a tough place and there are no guarantees.

[AshleyStroupe]

From the technical perspective, what lessons has the team learned from MER? If you could change something about the design of the rovers what would it be? Will this influence the design of future planetary rovers like Mars Science Laboratory?

That is a very tough question to answer because we have learned a lot. We have really learned much more about the challenges of driving, and what works well on different types of terrain. We have also learned how to drive aging rovers that don't have full capabilities anymore - this is really an entirely new field of robotics because here on Earth we just fix them when they break.

Unfortunately most of these lessons are too late to incorporate into our next rover, which is already well into production. But these will help us operate MSL and will be factored into future mission designs.

[Astrochimp]

On the other side of Mars from Spirit, Opportunity is making its way toward its next main goal, Endeavour Crater. The last estimate of time of transit to that crater I read was two years. How far has Opportunity progressed toward that goal since leaving Victoria Crater?

Also, what has the visit to Victoria Crater revealed to us so far?

[AshleyStroupe]

Hi Ashley,

Just today, scientists announced finding signs of water ice at the bottom of young craters on Mars at lower latitudes than expected. Would it be possible, given Opportunity's experience with exploring inside craters, that the rover could hunt - and study - ice at the bottom of an enormous crater like Endeavor, when it arrives? Does it have the right tools for that kind of job?

Thanks!

Tariq Malik

Anything is certainly possible, though I don't think Opportunity is quite at the latitudes where they're finding water. Given the thin Martian atmosphere, anything on the surface is long gone and Opportunity can't dig very deep. So it isn't very likely, but not impossible!

[AshleyStroupe]

On the other side of Mars from Spirit, Opportunity is making its way toward its next main goal, Endeavour Crater. The last estimate of time of transit to that crater I read was two years. How far has Opportunity progressed toward that goal since leaving Victoria Crater?

Also, what has the visit to Victoria Crater revealed to us so far?

We are about a quarter of the way there, and still have a ways to go. As to how long it will take, it will definitely depend o how many interesting things we find along the way! Like our recent stop at Block Island - the largest meteorite we have found on Mars which has taught us a lot about what Mars' atmosphere may have been like long ago.

[silylene]

Hello Ashley,

What was the single most exciting event that you participated in during your mars rovers project?

[AshleyStroupe]

Yes you can ask questions now.

Hello ashley,

Ok, If the robotic arm is used during the closest period that the robot has power to winter, the difference of the centre of gravity for the robot to weight ratio [because of temperature] might be enough to move the robot from the position it's stuck in that might aswell of changed it's manouverable dexterity potential, when will the power on the robot shut off? And potentially what sort of dust storm velosities offer chances?

The arm can't really shift the rover's center of gravity very much because it is small and low mass. Spirit also probably won't have to shut down this winter - based on our predictions she is clean enough that she can keep driving through the next Martian winter so we have plenty of time. I don't know the velocities of dust storms, but the winds are certainly enough to keep cleaning off the solar panels.

[AshleyStroupe]

Hello Ashley,

What was the single most exciting event that you participated in during your mars rovers project?

Wow this is a very tough question because there have been a lot! Personally, my first drive on Mars was very exciting for obvious reasons. Also, the day we discovered the first real evidence of wide-spread water at Spirit's landing site in Gusev crater changed the way we all think about Mars, which was very exciting.

[TariqJMalik]

Ashley, exactly who large is the team that drives Spirit and Opportunity? Do you have to train with the simulator on Earth in a sort of rover Driver's Ed, or is it something different?

Also, Spirit and Opportunity are the only active rovers on another planet right now. Can you give us an idea what if feels like - if you ever think about it - to actually be driving a car on Mars?

Thanks!

Tariq Malik

[AshleyStroupe]

Ashley, exactly who large is the team that drives Spirit and Opportunity? Do you have to train with the simulator on Earth in a sort of rover Driver's Ed, or is it something different?

Also, Spirit and Opportunity are the only active rovers on another planet right now. Can you give us an idea what if feels like - if you ever think about it - to actually be driving a car on Mars?

Thanks!

Tariq Malik

The team is still fairly large, we probably have about 20 people working on each rover each day that we plan. For driving, we do have very good simulators that we use to test our sequences before we send them to the rover, and we also use this for training. It takes a long time to be fully qualified and get your Mars driver's license.

As for what it feels like - it's really just awe inspiring. Probably the closest I'll ever get to being an astronaut. Going to new places and being the first human eyes to see them is profound and hard to describe. It's the best job I could imagine.

[FoxholeAthiest]

Hi Ashley,
Will you be involved with with the upcoming MSL mission too?

[AshleyStroupe]

Hi Ashley,
Will you be involved with with the upcoming MSL mission too?

I have already been involved with MSL to some extent. For the first time, we have images from orbiters (MRO) that gives us rover-scale details about the ground near the possible landing sites. I have been part of landing site selection team, looking at the data we have to try to predict how well the rover can drive at these places, and how long it will take to explore the major science targets.

I also of course hope to be doing driving when the time comes!

[High_Evolutionary]

Hello Ashley, Would it be not a possibility to have the second rover steer towards spirit in the attempts of dislodging it? Maybe a bump or a side swipe or would be to risky or time consuming to attempt this?