TOPICS > Science

Rovers on Mars

January 26, 2004 at 12:00 AM EDT


RAY SUAREZ: One day after landing on Mars, NASA’s newest probe, known as Opportunity, sent back what scientists described as a beautiful postcard from the red planet.

JIM BELL: We’re looking back out across a pretty spectacular landscape. It’s going to be a wonderful area for geologists to explore with our rover. We’ve started collecting what we call the mission success panorama with pan cam. This is a full 25 images all the way around, three images high, five colors, including the far infrared for pan cam. We started collecting that yesterday. We collected half of it — 180 degrees centered on that beautiful outcrop, so we’ll have even more of that spectacular geologic landscape in front of us.

RAY SUAREZ: The latest images capped a promising weekend for NASA. At 12:06 Sunday morning, scientists and engineers celebrated the rover’s on-time arrival after a trip of more than 280 million miles. Opportunity is the second American probe to land on Mars in less than three weeks, part of an $800 million-plus project.

The first probe, called Spirit, landed Jan. 3. Like Opportunity, it plunged into the Martian atmosphere at breakneck speed, 12,000 miles per hour. Protected by air bags, Opportunity landed in a crater on a plain called Meridiani, believed to be the smoothest and flattest spot on the planet. Scientists think there may have been water there once. Spirit landed halfway around the planet from Opportunity, more than 6,000 miles away.

At first, Spirit performed perfectly, sending back data and images. But last Wednesday, communication was interrupted. Today, scientists said they expected to repair Spirit’s software problems and hope it can resume exploring soon.

Here to tell us more about both rovers is Orlando Figueroa, director of NASA’s Mars exploration program. Well, after that initial exhilaration and realizing that the craft is landed safely and your communications channels are open and working, what do you do now?

ORLANDO FIGUEROA: Well, we certainly want to make sure we heal Spirit completely and continue to explore Gusev as we had started to do before the unfortunate situation of a few days ago, and then also get Opportunity ready to move off the lander and start exploring this magnificent place where we’ve landed at.

RAY SUAREZ: There’s been a lot of excitement in the scientific community, and especially on the Opportunity mission, about what you’re seeing in those initial photographs. Explain to someone who doesn’t understand exactly what they’re looking at why those surfaces and those substances that you’re seeing are such a revelation.

ORLANDO FIGUEROA: Well, we picked Meridiani as a landing site based on orbital observations that told us there perhaps was a great deal of hematite on the surface, and hematite is a mineral that only on Earth, though not the only way, can form under the presence of persistent water activity.

Now, we had the good fortune of having landed inside a small crater, where we … all the dust that we see around us, the darker color, is totally different from any other place we visited on Mars, unlike the Viking or Pathfinder or even Spirit’s surroundings. This looks completely different. We also see in the distance close to the rim of a crater bedrock, and these are the rocks that … the base rock actually that comes closest to the crust on the planet.

So we can tell a great deal about the history and evolution of the planet by looking at those rocks. We should be able to also rove off this crater over time after we’ve explored inside of it, and move onto other places, which promise to be as interesting as the place we landed at.

RAY SUAREZ: Well, once you roll Opportunity off the airbags that cushioned its landing, can it move very far in a day or do you have to be very careful about how quickly you move it around?

ORLANDO FIGUEROA: Well, usually the first few days are so much slower until the engineering team gets to become comfortable with the rover, get to understand exactly the soil they are moving in, and … but in a matter of a few … several days or a week, they’ll be ready to move on to a different site, and they can cover about 40 meters or so in a Martian day.

RAY SUAREZ: How long is a Martian day compared to an Earth day?

ORLANDO FIGUEROA: The Martian day is about 40 minutes longer than an Earth day, but, of course, a lot of the moving activity you want to do during the daylight when there is solar energy falling upon the solar array.

RAY SUAREZ: Is there a clock ticking on Opportunity? Is there only so many days of productive work that you know that you have?

ORLANDO FIGUEROA: Well, both missions were designed for a minimum of 90 days. That’s what we felt was the time necessary to do a significant exploration as a baseline mission. The predictions today based on the kind of environment that we observed, the temperature cycling on the batteries, and the dust that may be accumulating on the solar arrays, it appears it could go significantly longer — 100, 150, maybe even longer than that, days on the surface.

RAY SUAREZ: And when it’s ranging around … people have seen on Earth the beautiful photos that it’s taking. What can it … how far can it dig into the surface to see what’s under there?

ORLANDO FIGUEROA: Well, we could in essence start spinning the wheels in one location and dig as deep down as six inches or so, allowing us to expose some fresher material underneath, and bring some of the instruments much closer, including microscope and some of the other instruments to whatever we dig this hole.

RAY SUAREZ: And if you start to see things that are consistent with water once having been on Mars, will it just be a question of knowing that there was water, or will you some day be able to know how long ago that was?

ORLANDO FIGUEROA: Well, we would be able to tell whether the minerals or the layers that we observed were formed under the presence of persistent water activity. Now, for example, if a hematite we find is found to have been developed under the presence of water, we could tell, well, certainly water was there for a long period of time; how long would remain an open question for a while. We would need more data to do that and whether it was long enough for life to have evolved. These are the follow-up questions that will go after the MER missions.

RAY SUAREZ: And the prognosis for the other rover, Spirit? Is it much better now?

ORLANDO FIGUEROA: Indeed. I think over the last couple of days it was upgraded from critical to serious, and now it’s close to being declared stable, if not there already, now that we have a better understanding of what the problem is.

RAY SUAREZ: Well, it’s been called software problems, and I think anybody who’s tried to work their computer at home can identify with what a software problem is, but you can’t just pop in another CD and load a new program. How do you fix it from so far away?

ORLANDO FIGUEROA: Well, at the moment, we’re focusing on trying to understand precisely where the software problem may be. We think that the root cause has to do with the moving of large data files, and organization and coordination of data files within the flash memory.

Now, this is the memory where we tend to keep information for long periods of time. And so if … and if it proves for that to be the case, we can come up with fairly simple, relatively speaking, solutions and command new software or software patches, like you would do in a computer on the ground, except 100 million miles away, and update it. We would do that in Spirit and if need be in Opportunity as well to avoid ever getting into this situation.

RAY SUAREZ: Good luck with that, Orlando Figueroa, thanks for joining us.