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NASA Contacts Spirit Again
The US Spirit Mars rover communicated with Earth for 10 minutes overnight, one day after suffering a serious breakdown that cut off reception, NASA said Friday. Data sent by the rover was captured by one of the antennas of the international Deep Space Network near Madrid, Spain at 1234 GMT, NASA said. The communications came about 90 minutes after the start of the Martian day at a transmission speed of 10 bits per second, which is considered very weak. NASA engineers were to send Spirit several commands in the coming hours hoping to get some information about its condition and determine the source of its communication trouble. Specialists first noticed trouble with the rover when communications were interrupted on Wednesday, the rover's 19th day on the surface of the red planet.
Spirit Beeps It's Alive And "Commandable": NASA The command was tailored to the assumption that the rover's onboard computer is currently in a "fault mode", and the beep confirms that it has detected a serious fault, either in the hardware or the software. The fact that the rover responded at all, however, is encouraging. It suggests that the most serious potential cause of the malfunction -- a power failure -- has not occurred, although on the basis of what this reporter knows up to now it is still possible that the rover has suffered a partial power failure and is currently in a power-saving mode. The timing of the problem suggests that it may have been caused by a software error triggered by the rover's incomplete reception of the set of commands transmitted to it yesterday morning to set its planned sequence of actions for the day. A serious thunderstorm over the Canberra tracking station in Australia during the uplink prevented the full set of commands from being received by the rover. At this morning's press conference, JPL spokesmen stated their belief that the rover's computer was adequately programmed to recognize such an incomplete command set, and would deal with it by simply rejecting the entire set of new radioed orders and instead following a simpler set of preprogrammed instructions for the day. But on the basis of what we know at this point, it is probably not coincidence that Spirit's silence is due to a separate problem totally unrelated to that flawed command sequence. If so, the problem now facing JPL's engineers is to try to unsnarl the precise nature of whatever errors may have been produced in the rover's software by such an incomplete command set -- or by some other cause, such as a possible physical "upset" produced in one part of the computer's memory by a cosmic ray or solar radiation. This could be an extremely involved process, and it will certainly require extreme caution on the part of JPL's engineers, and extensive ground testing to confirm the appropriateness of every corrective command before it is actually radioed to Spirit. The Venus radar-mapping orbiter Magellan was almost destroyed twice during the first few days in which it orbited Venus -- thanks to an incredibly subtle software error which was only triggered by a set of circumstances which occurred about one one-millionth of the time, and which took four months to be tracked down and corrected. One additional hopeful fact, however, is that -- while spacecraft have frequently been lost before as a result of software errors -- in almost every case this has been because the software error caused the spacecraft to lose its attitude lock on the Sun, so that its solar arrays could no longer recharge its batteries and it ran out of power. Since Spirit is simply sitting on the surface of Mars with a set of rigid solar arrays fastened to its back, there is at least no danger of that happening in this case. The next regularly scheduled press conference regarding Spirit's status is not set until 10:00 AM Pacific time Friday morning. It is possible, however, that if new important developments occur, JPL will hold an unscheduled press briefing later today to report them -- something which has occurred many times in the past.
JPL Status Report However, the team is still trying to diagnose the cause of earlier communications difficulties that have prevented any data being returned from Spirit since early Wednesday. "We have a very serious situation," said Pete Theisinger of NASA's Jet Propulsion Laboratory, project manager for Spirit and its twin, Opportunity. Spirit did send a radio signal via NASA's Mars Global Surveyor orbiter Wednesday evening, but the transmission did not carry any data. Spirit did not make radio contact with NASA's Mars Odyssey during a scheduled session two hours later or during another one Thursday morning. It also did not respond to the first two attempts Thursday to elicit an acknowledgment signal with direct communications between Earth and the rover, and it did not send a signal at a time pre-set for doing so when its computer recognizes certain communication problems. The successful attempt to get a response signal came shortly before 9 a.m. Pacific Standard Time. No single explanation considered so far fits all of the events observed, Theisinger said. When the team tried to replicate the situation in its testing facility at JPL, the testbed rover did not have any trouble communicating. Two of the possibilities under consideration are a corruption of flight software or corruption of computer memory, either of which could leave Spirit's power supply healthy and allow adequate time for recovering control of the rover. Engineers will continue efforts to understand the situation in preparation for scheduled communication relay sessions using Mars Global Surveyor at 7:10 p.m. PST and Mars Odyssey at 10:35 PST. Efforts to resume direct communications between Spirit and antennas of NASA's Deep Space Network will resume after the rover's expected wake-up at about 3 a.m. PST Friday. Meanwhile, mission leaders decided to skip an optional trajectory correction maneuver today for Opportunity, the other Mars Exploration Rover. Opportunity is on course to land halfway around Mars from Spirit, in a region called Meridiani Planum, on Jan. 25 (Universal Time and EST; Jan. 24 at 9:05 p.m. PST).
earlier report "We have a very serious anomaly on the vehicle," said Pete Theisinger, project manager for the Mars Exploration Rover mission. The emergency came as the National Aeronautics and Space Administration prepared for the arrival on Mars this weekend of the second exploration rover, Opportunity. NASA said Wednesday that thunder and lightning storms over Australia had prevented scientists from sending Spirit its daily instructions. But experts now think a more serious problem caused the blackout. Theisinger said NASA experts had sent a command to Spirit on Thursday but are not sure if they got an acknowledgement. "I'm told that they think they got it, that would mean that the spacecraft thinks it is on the fault side of the tree for some reason, that would mean we've got positive power, some elements of the software are working. So that would be good news, but again, we need to confirm that." And Theisinger admitted that NASA was "very concerned". Spirit arrived on Mars January 3 and started searching for signs of past life on the red planet last week. Its twin rover, Opportunity, is due to touch down this weekend. The 820 million dollar mission expects each solar powered robot to keep working for about three months. NASA stopped receiving data from Spirit at about 1440 GMT on Wednesday, Theisinger said. Engineers first noticed the problem when they tried to send instructions to Spirit on Wednesday. They had attributed the lack of response to storms around the Deep Space Network antenna in Australia. Spirit is in the Gusev Crater, a rock-strewn, dusty terrain that NASA experts believe might have once been a lake and so could have supported life if there was water. NASA usually sends daily instructions to the rover and Spirit sends back information several times a day using two US satellites orbitting Mars. After troubles with the Mars Pathfinder mission in 1997 NASA had warned before Spirit left Earth in June that the latest attempt to find signs of life on Mars would be risky. The six-wheeled Mars Exploration Rovers are 1.6 metres (5.2 feet) long and have a 1.5 metres (4.9 feet) high camera mast. Each rover is packed with sensitive equipment to search for signs that their may have been water on Mars in the past that could have sustained life. Since it landed on Mars, Spirit's 360-degree camera has sent back spectacular colour and infra-red panoramic images of the surface. But problems with the airbags that cushioned the January 3 landing held up the start of the exploration on the surface. The second, Opportunity, is due to land on another part of the planet at about 0500 GMT Sunday. Each rover was intended to work for at least 90 martian days, which would have taken the Spirit mission until late April. The expeditions were intended to overcome the disappointment of the Orbiter, which left Earth in December 1998 but disappeared on arrival, as well as the Polar Lander rocket, which crashed into the planet in 1999 when its landing system broke down. A US Pathfinder rocket was the first vehicle to land on Mars in 1997. A small robot was put on the surface to gather information. President George W. Bush last week announced a new space initiative aiming to set up a manned base on the moon from about 2015 and which would eventually send human missions to Mars and beyond.
Spaceflightnow - NASA Briefing transcript report
Thursday, Jan 22, 2004 Spaceflightnow.com has reported the following transcript notes. Check SFN's mission status page for ongoing updates. Space.TV will have the morning's briefing shortly or can be picked up on regular replay via NASA TV Here is project manager Pete Theisinger's briefing to reporters in the last hour, describing what has happened: "At yesterday's press conference, we reported to you that we had had some communications issues with the rover, which we thought at the time was due to weather at the Canberra station and (Deep Space Network) configuration issues. "We now know we have had a very serious anomaly on the vehicle, and our ability to determine exactly what has happened has been limited by our inability to receive telemetry from the vehicle, basically the last 12 hours or so. "Let me kind of describe what the sequence of events have been. "Yesterday afternoon, local solar time on Mars, actually about 1 o'clock, we sent to the vehicle at a command rate of 31.25 bits per second a sequence. We activated that sequence by command and we received a beacon response that indicated that we vehicle had received that sequence and that it was activating that sequence. "After that time, a scheduled high-gain antenna pass at 2 o'clock in the afternoon, roughly, local solar time on Mars, did not occur. "The 4:30 p.m. afternoon Mars Odyssey afternoon pass did not occur in the sense there was no indication by Odyssey that they received a UHF transmission. "Last night, we had about a 1:30-2 a.m. Mars Global Surveyor pass and it was anomalous in the sense that Mars Global Surveyor believes it saw UHF transmission in its receiver telemetry but there was no data in the packets and the period of time that it believed it saw UHF telemetry was very, very short -- about two-and-a-half minutes compared to 12- or 13-minute overflight. "The 4 a.m. Odyssey pass received no data, and this morning we did not have a direct-to-Earth link session -- we did not receive data on the normal direct-to-Earth session, nor did we receive data on what would have been a fault session at 11 a.m., which is where the spacecraft has entered fault mode, knows that, and chooses to communicate with us at a different time. "The team has been meeting this morning and through the night working on a set of postulated fault scenarios. There is no one single fault that explains all the observables -- that we know of at the present time that we can conceive. "We have been working on fault scenarios, we have been developing to-do lists. We have run yesterday's sequences through the test-bed (on Earth) with no anomalous results. So that is kind of our current state of knowledge." At the end of the news conference, mission manager Jennifer Trosper came into the room and delivered an update to deputy project manager Richard Cook sitting at the briefing desk. "If the spacecraft believes it's in a fault mode, its command rate should be 7.8 bits per second. We sent a beep today, this morning, about the time that we came down here to talk to you at 7.8. We sent a command that says if you get this send us a beep. And I'm told from Richard that Jennifer came down here to tell us that they think they got it," Theisinger said. "That would tell us that the spacecraft thinks it's in the fault side of the tree some how for some reason. That would mean that we've got positive power, some elements of the software is working, once again the X-band system is working, the SSPA, the multi-space transponder, all that stuff is working so that would be more information -- good news. We need to confirm that. Data off the DSN sometimes needs double-checking. We'll let you know if that's for sure." AFP wire reports were partly used to file this report Related Links Mars Rovers at JPL Mars Rovers at Cornell SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express 
Martian Science Season Gets Off To A Rocky Start
Pasadena - Jan 20, 2004NASA's Spirit rover has successfully driven to its first target on Mars, a football-sized rock that scientists have dubbed Adirondack. The Mars Exploration Rover flight team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., plans to send commands to Spirit early Tuesday to examine Adirondack with a microscope and two instruments that reveal the composition of rocks, said JPL's Dr. Mark Adler, Spirit mission manager. The instruments are the M�ssbauer spectrometer and the alpha particle X-ray spectrometer.
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