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January 22, 2004

NASA scientists have not received any transmissions from their Martian rover Spirit in over 24 hours. Jeffrey Brown discusses this setback with Charles Elachi, director of the NASA Jet Propulsion Laboratory in Pasadena, Calif.

 

Online NewsHour Special Reports: Mars Exploration Rovers Jan. 22, 2004: Update: Mars Rover Stops Transmitting Data Jan. 15, 2004: The robotic rover Spirit rolled off its landing platform Thursday to start searching for signs that water once existed on Mars. Jan. 14, 2004: President Bush unveils Moon-Mars program. Jan. 5, 2004: The NASA rover Spirit landed on Mars and started sending detailed images of the planet's surface. May 29, 2003: Jeffrey Kaye of KCET Los Angeles reports on the latest Mars lander program. Browse the NewsHour's coverage of science.   News for Students: Lesson Plan: Planets in Proportion     Jet Propulsion Laboratory's Mars Exploration Rover Mission Web site	JEFFREY BROWN: It's been more than 24 hours since NASA scientists have received data from the rover called Spirit, which sits in a large crater on Mars. Up to this point, Spirit has functioned nearly flawlessly. But today, one of the leaders of the Mars project acknowledged what he called a "serious problem." Joining us now is the director of the Jet Propulsion Laboratory in Pasadena, Charles Elachi. Dr. Elachi, welcome back to our program. The phrase used by one of the scientists at today's briefing was, "an extremely serious anomaly has occurred." What does that mean? CHARLES ELACHI: What has happened is starting 24 hours ago, we have been seeing anomalous behavior. At certain times, when we communicate with the spacecraft, we do get a signal back; at certain times we don't get a signal back. And we have not received any data when it was scheduled to give data. However, the latest event, which occurred few hours ago: On a certain channel, we inquired the spacecraft to tell us if it's there, and we got the expected response: "Yes, I'm here," for five minutes. That tells us that the spacecraft is in a certain safe mode that we are going to start exercising tomorrow. JEFFREY BROWN: They've been referring to these as beeps that you're getting back. Is that what you're talking about? What are those beeps? CHARLES ELACHI: That is correct. What we usually do is first we send a signal to the spacecraft saying, "Are you there? Tell us if you are there" on a certain channel. And then we get back a signal. And remember, that takes ten minutes for the signal to get to Mars and ten minutes to come back. Basically the spacecraft said, "Yes, I'm here," and transmitted the signal. And what that will allow us to verify that we do have a communication link, a capable communication link with that spacecraft. JEFFREY BROWN: So it may mean that Spirit is saying, "Yes, I'm here," but it's not doing what you're telling it to do? CHARLES ELACHI: That could be a possibility. That's why we are puzzled a little bit and we're trying to understand these anomalies, why aren't we getting the normal behavior. So one of the key things we need to do tomorrow is to communicate to it on this specific channel where we got the response, and have it transmit to us some of its engineering data -- if you want, some of its memory -- so we can do a diagnostic and understand what has happened, what are the corrective actions that need to be done, and how do we bring it carefully and thoughtfully to its normal operation mode.
	Possible causes of the problem
	JEFFREY BROWN: Well, I know that scientists right now are running through various scenarios. Give us some of the possible problems that you're looking at. CHARLES ELACHI: I mean, there could be that for some reason, there was some corruption in the memory of the spacecraft. It's similar to what happens at your computer at home. You know, sometimes some error comes in, or some bugs that comes in, or it could have been some rays which have hit the spacecraft and disturbed some part of the memory so it's behaving abnormally. And the way we set these spacecraft is that if there is something abnormal, it goes into a certain safe mode, and the indication when we linked and it responded positively is that it's most likely into a certain safe mode, that that will allow us then to bring it out of that safe mode. JEFFREY BROWN: Scientists today talked about problems potentially in the software or hardware. Tell us what that means. What do they mean by the software, first? CHARLES ELACHI: Well, the software is all the programs that we have on the spacecraft, which are operating the spacecraft -- again, similar to your computer at home. So if there is a software problem, what they need is to get the diagnostics coming down to us. Now, remember, we are doing this at 100 million miles away, so it is like you are doing a diagnostic of your car, but the car is 100 million miles away and linked to you by a data link. Once we get those diagnostics down, then we have a number of actions: One, we can correct the specific problem, or ultimately if it's needed, we can reboot the whole spacecraft like you reboot your computer. But that's something we have to do it carefully and thoughtfully because we have a very valuable asset up there that we did a lot of hard work to get it safely there; the public is all excited about it; so we need to do things methodically or carefully. There is nothing which is rushing us to actually go and do something immediately. The spacecraft has power; the temperature seems to be appropriate; so nothing is rushing us to go and do any rush job on this one. JEFFREY BROWN: So if it's a software problem, you're saying that likely is fixable? CHARLES ELACHI: Yes. I mean, you can update the software, and even if sometimes it's a hardware problem, you can work your way around it. JEFFREY BROWN: Well, explain to us ... I'm sorry. Could you explain to us what you mean by hardware? CHARLES ELACHI: I mean hardware could be some sensors which are not working right, some memory which has failed, and things of that nature. And there are ways sometimes to work around the hardware, you know, problem -- again, like if part of your computer fail, you can be able to work around it.
	Next steps, and next lander
	JEFFREY BROWN: So what happens next? CHARLES ELACHI: OK, the plan next, now, we had the team to go home and rest, and then at 5 tonight, they'll come back and work the plan for the next communication opportunity, which occurs at 3 a.m. Pacific Time tomorrow morning. We will be using the same channel that we used earlier this morning and we got the positive response. And the reason we want to do that carefully and thoughtfully is we have Opportunity which is coming to land, so we have two spacecraft here. And as I said, there is nothing rushing us to do the fix immediately, other than people being anxious. But one of the key things we learn is the best thing is to stay calm and thoughtful and methodical, and not to rush to judgment and try to do things too quickly. This is the same ... similar situation happened on Voyager and on Magellan and on previous missions, and our disciplined engineers calmly and quietly were able to bring the spacecraft back up, instead of rushing and doing immediate action. JEFFREY BROWN: As you said, Opportunity -- the other rover -- is scheduled to land Saturday night. Do the problems with Spirit pose any potential problems to that? CHARLES ELACHI: No, we don't think so because we are doing the same process that we did on Spirit for the entry, descent and landing. All the software is onboard. We have verified all the software, so it's basically autonomous now, and ... unless we need to intervene. But it looks ... all indication is that it's working nominally the same way that Spirit worked nominally. JEFFREY BROWN: I know you've talked about everyone remaining calm at this point. This mission has been so successful up to this point; has the mood changed at all at the Jet Propulsion Lab? CHARLES ELACHI: No. I mean, in a sense, you get always concerned when you have an anomaly. On the positive side, you know, we are pleasantly impressed by how much the public is interested, you know, in this mission. And as you know, we have had so far three billion -- that's billion with a B -- hits on our Web page to see what are the exciting results. Already we have done a lot of science by having the mosaics, the images, and already has improved our understanding about Mars. But clearly, when you have an anomaly, and we still have a long mission, you know, to conduct for another two, three months, we are concerned. And that's the appropriate thing. We are concerned, but we are approaching it in a calm, methodical way. JEFFREY BROWN: All right, Dr. Charles Elachi, thank you very much again. CHARLES ELACHI: Thank you.