Regular readers of “Road to Endeavour” will already know what a great friend Mars rover driver Scott Maxwell is to this blog. I was priviliged to be shown around parts of JPL by Scott a couple of years ago, including a very memorable visit to the heart of MER operations, and several times since then he has been kind enough to answer questions I’ve sent him, for this blog, about Oppy’s ongoing adventure. I thought that now Oppy has left Santa Maria far behind, and is steaming towards Endeavour, it might be a good time to catch up with Scott again and check how he thinks things are going. And, typically, Scott was good enough to take some time out of his busy schedule to submit to my latest email grilling!
So, let’s hear from one of Opportunity’s drivers how things are going with her great Meridiani trek…
1.So… Oppy’s on the road again… how does it feel?
What’s even better is the fact that the terrain we’re on now is just a parking lot — not a parking lot with speed bumps in it, as we mostly had on the way to Santa Maria, but a parking lot, period. This means we can do longer blind drives, and longer drives per sol. We’ve pushed 140m/sol, and we’re going to do better than that as solar energy and friendly driving terrain combine to push us even higher.
That’s not to say Santa Maria wasn’t entertaining — it was, and it gave us a chance to bust out tricks we haven’t used for a while. But nothing beats putting the pedal to the metal.
2.I know that as a rover driver you’re probably very restless, fidgety and impatient whenever Oppy parks up to allow the rock hounds and science guys to study something, but didn’t you think that Santa Maria was pretty amazing? It looked fairly uninspiring from HiRISE images before we got there, but what a place…
Santa Maria was definitely a nifty place, with its dramatically steep cliffs and fun platy outcrops we could put the IDD down on. But the best part is what it looks like in the rear-view mirror.
3.HiRISE is helping you guide Oppy towards Endeavour. Can you describe what it’s like having the wonderful HiRISE images to help guide your drives now, compared to Ye Olde Days?
It’s a terrible irony that we could have *really* used HiRISE for
getting through the etched terrain between Endurance and Victoria. Back then, all we had was MOC images, with resolutions of — I don’t remember, maybe 1m/pixel or even larger? It was still very valuable, and of course we managed to make it through, but it was a terribly muddy view compared to what HiRISE could have done for us. Now, thanks to HiRISE, we have something like 20-25cm/pixel — a tremendous improvement. At the moment, of course, we’re on flat terrain that MOC could resolve plenty well for driving purposes. *sigh*
Even if HiRISE isn’t as useful as it might be for pure driving,
however, that’s not to say it’s useless! The higher-resolution views help Dr. Tim Parker localize the rover every sol, so we know right where we’re starting, usually to within 50cm or so. I don’t think MOC would have given him a good enough picture to do that, and that has been incredibly valuable for us.
4.We’re now less than 5km away from Cape York, and Oppy is really driving hard. Can you tell us just how you’re making such great progress across Meridiani now? I know that the flat terrain is a godsend, but what special “drivers tricks” are being employed now?
The flat terrain works for us in two ways. First, it helps us extend the blind drives — this is the part of the drive where we just say to Opportunity, “go *there* and trust me!” The blind portion is much faster, since Opportunity doesn’t have to do a lot of thinking with her poor slow 20MHz brain. The fact that the terrain is so flat means we’re limited mainly by the resolving power of the MER (PANCAM) optics, which can detect a rover-hazard obstacle out to maybe 100m or so under ideal conditions like these. When we had ripples to deal with, we had to worry that the ripples might be hiding an obstacle, and our blind segments were consequently limited to maybe 70m.
Second, we’re getting more value out of our neat little drive-extension trick, where we use autonomous navigation to proceed
past the 100m line. This is where we stop every 1.2m, turn, and have Opportunity image the terrain she’s about to drive into. She then turns back on course and proceeds into it if she can see that it’s safe. This part goes more slowly because Opportunity has to think so much, but it lets us pick up 20-40m/sol that otherwise we wouldn’t get at all — a free drive every 3-5 sols, essentially. Back when we had ripples, Opportunity would occasionally see the ripples as hazards and stop the drive early. (The ripples weren’t really hazards, but Opportunity is very conservative.) Now she just plows ahead until time runs out.
This still isn’t as good as the days when we could drive forward.
When it’s going forward, the autonomous hazard-avoidance driving could be more flexible — in several ways, but in particular, it could autonomously decide to skip some imaging steps when that was safe — so we could drive 200m/sol or even a little better. Still, we’re getting a pretty good fraction of Opportunity’s potential — we’ll get it up to about 160m/sol, a pretty decent fraction of the 200m/sol we’re capable of — and that’s not bad for a 7-year-old 90-day mission!
5.Every sol now the faraway hills of Endeavour’s rim are a little
closer, a little taller. What does it feel like, as a driver, to see
those images for the first when they come in – and how confident is
the team that Oppy will reach Endeavour’s rim now?
Oh, we’re definitely getting there. Frank and I were just talking
about this the other day: it’s exciting to see those hills rising on
the horizon! Driving across this flat stuff is awesome, but it’s
gonna be fun to go hill-climbing again, too. We haven’t done that
since the early(ish) days of Spirit.
6.Obviously I have to ask about Spirit. Although she’s been silent for over a year now, the MER team is obviously still determined to try absolutely everything they possibly can to regain contact, if that’s possible…
I still have my fingers crossed. They may be aching, but they’re
crossed. Spirit has done a lot for us, and we’re gonna give her every chance to reach out to us. If we don’t hear from her — well, I’ll drive Opportunity wearing a black armband for a while.
It would be just like her, though, to wait until everyone’s given up and NASA has issued the press release declaring her dead — and *then* pipe up. And that’ll be OK with me. I just want to hear that my girl’s alive.
7.Back to Oppy. As Oppy steams towards Endeavour it’s clear that
there’s still a lot of public interest in the rovers, and the
“armchair explorers” out here are very excited by the prospect of Oppy making landfall at Cape York; it almost feels like a new mission to many of us. Do you feel that way? Has this sprint to Endeavour re-energised you and the team?
That’s something else Frank and I have talked about a lot, actually — how every new destination feels like a new mission. Eagle was one, and Endurance was one, and the heat shield, and Victoria … heck, they just keep coming, don’t they?
As far as re-energizing me personally, I don’t think I work that way. I have something wrong with me where the coolness of things doesn’t wear off with time. Driving a robot around Mars is every bit as mind-blowing for me now as it was when we started seven years ago — I’m a lot more confident in it now, but the awesome factor hasn’t worn off yet, and I don’t think it’s going to. (I just gave a tour to fellow Twitteratum Heather “@Pillownaut” Archuletta and her mom and her friend today, and I found myself just as excited as I would have been on Sol 1.)
8.Since the rovers arrived on Mars, have your feelings about Mars
itself changed? Do you now see the landscape differently, after all
this time driving across it? Does it seem less or more beautiful? Less or more dangerous? Have any particular views been particularly moving for you personally?
When we landed, I used to feel terrible about scuffing up the surface. Like, it’s been sitting there pristine and undisturbed for a few billion years, until *I* came along and messed everything up, you know?
I see the landscape differently now in a sort of technical sense –
I’m better and faster at picking out terrain features of interest, for instance, just from long years of practice, and overall it seems less dangerous in that I feel like I know what to look for. (Bearing in mind, of course, that there’s such a thing as perfectly camouflaged rover traps such as the one that got Spirit. But I don’t worry too much about those because it’s impractical: if Mars really wants to eat you, it’s just going to.) But in an aesthetic sense, not so much has changed. It’s still this weirdly alien frozen desert, beckoning us on.
There are more moving views than I can count, but I’d call out two that stand out above the others in my mind. First, of course, is the “Everest Panorama,” Spirit’s view from the top of Husband Hill. I know what it took for both her and us to get there, and — admitting that I see all of that, not just the image itself, when I look at it — I think it ranks among the very finest images in all of space exploration.
Second is the first view of Earth from Mars. I have that one printed out and posted up near my development workstation. I cannot say in a few words what that image means to me, but among many other things, it gives me perspective. That tiny, fragile little dot in a sea of black, that’s our house as seen from the front porch steps of our neighbor’s house. In a vast, vast neighborhood.
9.Finally, after seven years on Mars, in the quiet moments, does it
ever hit you that you’re actually making history with this mission?
Does it ever scare or spook you to think that in centuries to come the rovers you drive will be seen as important as “Eagle”, “Challenger” , “Viking”, and the other famous spacecraft from the history of space exploration?
Funny enough, I never really thought about that until I went to the eye doctor a couple of years ago. He started asking me questions about it, from the perspective of someone looking back at this mission from a hundred years in the future, and only then did I think — holy crap, people are actually going to *do* that! I’m going to exist for them only as the most minor of footnotes, a name in some uplink reports, but Spirit and Opportunity are going to be as real for them as Armstrong’s Eagle is for me. (Of course, I’d *hope* that they’ll be visiting the rovers in person — born on Mars, and going to see the rovers on class field trips, as you’ve so eloquently written about.)
For me, it’s yet another reason to try to do my job as professionally and as well as I can — I have a responsibility to those generations now in school, or in diapers, or yet unborn, to use these rovers in a way they’d be proud of.
And, what the hell, to have some fun along the way.
Thanks again to Scott Maxwell for taking the time to talk to RtE!