Author Topic: Mars Exploration Rovers Update  (Read 194904 times)

Offline John44

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Re: Mars Exploration Rovers Update
« Reply #40 on: 01/16/2009 11:41 AM »

Online jacqmans

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Re: Mars Exploration Rovers Update
« Reply #41 on: 01/29/2009 03:10 AM »
Mars Exploration Rover Mission Status Report

Mars Rover Team Diagnosing Unexpected Behavior


CORRECTION: In paragraph 3--Early Tuesday, Spirit reported that it had followed the commands, and in fact had located the sun, but not in its expected location.

PASADENA, Calif. - The team operating NASA's Mars Exploration Rover Spirit plans diagnostic tests this week after Spirit did not report some of its weekend activities, including a request to determine its orientation after an incomplete drive.

On Sunday, during the 1,800th Martian day, or sol, of what was initially planned as a 90-sol mission on Mars, information radioed from Spirit indicated the rover had received its driving commands for the day but had not moved. That can happen for many reasons, including the rover properly sensing that it is not ready to drive. However, other behavior on Sol 1800 was even more unusual: Spirit apparently did not record the day's main activities into the non-volatile memory, the part of its memory that persists even when power is off.

On Monday, Spirit's controllers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., chose to command the rover on Tuesday, Sol 1802, to find the sun with its camera in order to precisely determine its orientation. Not knowing its orientation could have been one possible explanation for Spirit not doing its weekend drive. Early Tuesday, Spirit reported that it had followed the commands, and in fact had located the sun, but not in its expected location.

"We don't have a good explanation yet for the way Spirit has been acting for the past few days," said JPL's Sharon Laubach, chief of the team that writes and checks commands for the rovers. "Our next steps will be diagnostic activities."

Among other possible causes, the team is considering a hypothesis of transitory effects from cosmic rays hitting electronics. On Tuesday, Spirit apparently used its non-volatile memory properly.

Despite the rover's unexplained behavior, Mars Exploration Rovers' Project Manager John Callas of JPL said Wednesday, "Right now, Spirit is under normal sequence control, reporting good health and responsive to commands from the ground."

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Exploration Rover project for the NASA Science Mission Directorate, Washington. Spirit and its twin, Opportunity, landed on Mars in January 2004 and have operated 20 times longer than their original prime missions.

                                                     -end-

Offline ChrisGebhardt

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Re: Mars Exploration Rovers Update
« Reply #42 on: 01/29/2009 03:59 AM »
Hope Spirit is all right. But what a journey that little rover and it's companion Opportunity have had.

Offline I14R10

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Re: Mars Exploration Rovers Update
« Reply #43 on: 01/29/2009 02:26 PM »
Hope Spirit is all right. But what a journey that little rover and it's companion Opportunity have had.

I can only imagine how long MSL will work.  :)
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Offline stockman

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Re: Mars Exploration Rovers Update
« Reply #44 on: 01/29/2009 02:28 PM »
Hope Spirit is all right. But what a journey that little rover and it's companion Opportunity have had.

I can only imagine how long MSL will work.  :)

Actually it better... the one down side to having both of the MER rovers work for so long is that it sets the bar very high for the followon MSL... The bigger, badder more expensive machine will be deemed a partial failure if it does not at least equal the time on Mars that the rovers accomplish...

but --- no pressure.. ;)
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Offline Nick L.

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Re: Mars Exploration Rovers Update
« Reply #45 on: 01/29/2009 05:13 PM »
These two sure are amazing. It's just awesome how long they have lasted.

Hope Spirit gets better! :D
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Offline mjcrsmith

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Re: Mars Exploration Rovers Update
« Reply #46 on: 01/29/2009 05:48 PM »
One of the greatest benefits of MER is that we now have data on the systems that have been able to operate in the Martian environment for 5 years.  The data gathered will be very useful by the engineers that will design future systems and vehicles.  As good as simulations are, there is nothing like the real thing.

I know we need to progress towards precise landings of larger vehicles like MSL so ultimately we can get humans to do the exploration.  However, in a perfect world, it would be cool to have a 10 more Spirit's and Opportunities doing some basic recon work.

Hoping Spirit and Opportunity keep on truckin'!
« Last Edit: 01/29/2009 05:51 PM by mjcrsmith »

Online jacqmans

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Re: Mars Exploration Rovers Update
« Reply #47 on: 03/05/2009 07:20 PM »
NEWS RELEASE: 2009-041                                                                                    March 5, 2009

NASA's Mars Rover Spirit Faces Circuitous Route

PASADENA, Calif. -- Loose soil piled against the northern edge of a low plateau called "Home Plate" has blocked NASA's Mars Exploration Rover Spirit from taking the shortest route toward its southward destinations for the upcoming Martian summer and following winter.

The rover has begun a trek skirting at least partway around the plateau instead of directly over it.

However, Spirit has also gotten a jump start on its summer science plans, examining a silica-rich outcrop that adds information about a long-gone environment that had hot water or steam. And even a circuitous route to the destinations chosen for Spirit would be much shorter than the overland expedition Spirit's twin, Opportunity, is making on the opposite side of Mars.

Both rovers landed on Mars in 2004 for what were originally planned as three-month missions there.

Spirit spent 2008 on the northern edge of Home Plate, a flat-topped deposit about the size of a baseball field, composed of hardened ash and rising about 1.5 meters (5 feet) above the ground around it. There, the north-facing tilt positioned Spirit's solar arrays to catch enough sunshine for the rover to survive the six-month-long Martian winter.

The scientists and engineers who operate the rovers chose as 2009 destinations a steep mound called "Von Braun" and an irregular, 45-meter-wide (150-foot-wide) bowl called "Goddard." These side-by-side features offer a promising area to examine while energy is adequate during the Martian summer and also to provide the next north-facing winter haven beginning in late 2009. Von Braun and Goddard intrigue scientists as sites where Spirit may find more evidence about an explosive mix of water and volcanism in the area's distant past. They are side-by-side, about 200 meters, or yards, south of where Spirit is now.

It's mid-spring now in the southern hemisphere of Mars. The sun has climbed higher in the sky over Spirit in recent weeks.

The rover team tried to drive Spirit onto Home Plate, heading south toward Von Braun and Goddard. They tried this first from partway up the slope where the rover had spent the winter. Only five of the six wheels on Spirit have been able to rotate since the right-front wheel stopped working in 2006. With five-wheel drive, Spirit couldn't climb the slope. In January and February, Spirit descended from Home Plate and drove eastward about 15 meters (about 50 feet) toward a less steep on-ramp. Spinning wheels in loose soil led the rover team to choose another of its options.

"Spirit could not make progress in the last two attempts to get up onto Home Plate," said John Callas of NASA's Jet Propulsion Laboratory, Pasadena, Calif., project manager for both rovers. "Alternatively, we are driving Spirit around Home Plate to the east. Spirit will have to go around a couple of small ridges that extend to the northeast, and then see whether a route east of Home Plate looks traversable. If that route proves not to be traversable, a route around the west side of Home Plate is still an option."

During the drive eastward just north of Home Plate in January, Spirit stopped to use tools on its robotic arm to examine a nodular, heavily eroded outcrop dubbed "Stapledon," which had caught the eye of rover-team scientist Steve Ruff when he looked at images and infrared spectra Spirit took from its winter position.

"It looked like the material east of Home Plate that we found to be rich in silica," said Ruff, of Arizona State University, Tempe. "The silica story around Home Plate is the most important finding of the Spirit mission so far with regard to habitability. Silica this concentrated forms around hot springs or steam vents, and both of those are favorable environments for life on Earth."

Sure enough, Spirit's alpha particle X-ray spectrometer found Stapledon to be rich in silica, too.

"Now we have found silica on a second side of Home Plate, expanding the size of the environment we know was affected by hot springs or steam vents," Ruff said. "The bigger this system, the more water was involved, the more habitable this system may have been."

The contact measurement with the X-ray spectrometer also gave the team confidence in its ability to identify silica-rich outcrops from a distance with the rover's thermal emission spectrometer, despite some dust that has accumulated on a periscope mirror of that instrument. Researchers plan to use Spirit's thermal emission spectrometer and panoramic camera to check for more silica-rich outcrops on the route to Von Braun and Goddard. However, the team has set a priority to make good progress toward those destinations. Winds cleaned some dust off Spirit's solar panels on Feb. 6 and Feb. 14, resulting in a combined increase of about 20 percent in the amount of power available to the rover.

Opportunity, meanwhile, shows signs of increased friction in its right-front wheel. The team is driving the rover backwards for a few sols, a technique that has helped in similar situations in the past, apparently by redistributing lubricant in the wheel. Opportunity's major destination is Endeavour Crater, about 22 kilometers (14 miles) in diameter and still about 12 kilometers (7 miles) away to the southeast. Opportunity has been driving south instead of directly toward Endurance, to swing around an area where loose soil appears deep enough to potentially entrap the rover.

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Exploration Rovers for the NASA Science Mission Directorate, Washington. More information about the rovers is at http://www.nasa.gov/rovers .


Online jacqmans

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Re: Mars Exploration Rovers Update
« Reply #48 on: 03/18/2009 08:49 PM »
NEWS RELEASE: 2009  053     
                                                                           
March 18, 2009


One Mars Rover Sees a Distant Goal; The Other Takes a New Route

PASADENA, Calif. -- On a plain that stretches for miles in every direction, the panoramic camera on NASA's Mars rover Opportunity has caught a first glimpse on the horizon of the uplifted rim of the big crater that has been Opportunity's long-term destination for six months.

Opportunity's twin, Spirit, also has a challenging destination, and last week switched to a different route for making progress.

Endeavour Crater, 22 kilometers (14 miles) in diameter, is still 12 kilometers (7 miles) away from Opportunity as the crow flies, and at least 30 percent farther away on routes mapped for evading hazards on the plain. Opportunity has already driven about 3.2 kilometers (2 miles) since it climbed out of Victoria Crater last August after two years of studying Victoria, which is less than one-twentieth the size of Endeavour.

"It's exciting to see our destination, even if we can't be certain whether we'll ever get all the way there," said John Callas of NASA's Jet Propulsion Laboratory, Pasadena, Calif., project manager for the twin Mars rovers, Opportunity and Spirit. "At the pace we've made since leaving Victoria, the rest of the trek will take more than a Martian year." A Martian year lasts about 23 months.

The image with portions of Endeavour's rim faintly visible can be seen online at http://www.nasa.gov/mission_pages/mer/images/mer20090318.html .

Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' science instruments, said, "We can now see our landfall on the horizon. It's far away, but we can anticipate seeing it gradually look larger and larger as we get closer to Endeavour. We had a similar experience during the early months of the mission watching the Columbia Hills get bigger in the images from Spirit as Spirit drove toward them."

Both rovers landed on Mars in January 2004 to begin missions designed to last for three months. Both are still active after more than five years.

For the next several days, the rover team plans to have Opportunity use the tools on its robotic arm to examine soil and rock at an outcrop along the route the rover is taking toward Endeavour.

"We're stopping to taste the terrain at intervals along our route so that we can watch for trends in the composition of the soil and bedrock," Squyres said. "It's part of systematic exploration."

The pause for using the tools on the arm also provides two other benefits. Opportunity's right-front wheel has been drawing more electric current than usual, an indication of friction within the wheel. Resting the wheel for a few days is one strategy that has in the past helped reduce the amount of current drawn by the motor. Also, on March 7, the rover did not complete the backwards-driving portion of its commanded drive due to unanticipated interaction between the day's driving commands and onboard testing of capabilities for a future drive. The team is analyzing that interaction before it will resume use of Opportunity's autonomous-driving capabilities.

Meanwhile, on March 10, the rover team decided to end efforts to drive Spirit around the northeastern corner of a low plateau called "Home Plate" in the inner basin of the Columbia Hills, on the other side of Mars from Opportunity. Spirit has had the use of only five wheels since its right-front wheel stopped working in 2006. Consequently, it usually drives backwards, dragging that wheel, so it can no longer climb steep slopes.

Callas said, "After several attempts to drive up-slope in loose material to get around the northeast corner of Home Plate, the team judged that route to be impassable."

The new route to get toward science targets south of Home Plate is to go around the west side of the plateau.

Squyres said, "The western route is by no means a slam dunk. It is unexplored territory. There are no rover tracks on that side of Home Plate like there are on the eastern side. But that also makes it an appealing place to explore. Every time we've gone someplace new with Spirit since we got into the hills, we've found surprises."


Offline eeergo

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Re: Mars Exploration Rovers Update
« Reply #49 on: 03/19/2009 12:19 PM »
Amazing, it seems just yesterday that Opportunity was getting out of Victoria, and it has already surpassed 3 km... built to last :D
-DaviD-

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Re: Mars Exploration Rovers Update
« Reply #50 on: 04/14/2009 08:39 AM »
NEWS RELEASE: 2009-066                                                                             April 13, 2009


Spirit Healthy but Computer Reboots Raise Concerns

Mars Exploration Rover Mission Status Report

The team operating NASA's Mars Exploration Rover Spirit is examining data received from Spirit in recent days to diagnose why the rover apparently rebooted its computer at least twice over the April 11-12 weekend.

"While we don't have an explanation yet, we do know that Spirit's batteries are charged, the solar arrays are producing energy and temperatures are well within allowable ranges. We have time to respond carefully and investigate this thoroughly," said John Callas of NASA's Jet Propulsion Laboratory, Pasadena, Calif., project manager for Spirit and twin-rover Opportunity. "The rover is in a stable operations state called automode and taking care of itself. It could stay in this stable mode for some time if necessary while we diagnose the problem."

Spirit communicated with controllers Friday, Saturday and Sunday, but some of the communication sessions were irregular. One of the computer resets apparently coincided in timing with operation of the rover's high-gain dish antenna.

The rover team has the advantage of multiple communication options. Spirit can communicate directly with Earth via either the pointable high-gain antenna or, at a slower data rate, through a low-gain antenna that does not move. Additionally, communications can be relayed by Mars orbiters, using the UHF (ultra-high frequency) transceiver, a separate radio system on the rover.

"To avoid potential problems using the pointable antenna, we might consider for the time being just communicating by UHF relay or using the low-gain antenna," Callas said.

Spirit finished its three-month prime mission on Mars five years ago and has kept operating through multiple mission extensions.

The rover's onboard software has been updated several times to add new capabilities for the mission, most recently last month. The team is investigating whether the unexpected behavior in recent days could be related to the new software, but the same software is operating on Opportunity without incident.

"We are aware of the reality that we have an aging rover, and there may be age-related effects here," Callas said.

In the past five weeks, Spirit has made 119 meters (390 feet) of progress going counterclockwise around a low plateau called "Home Plate" to get from the place where it spent the past Martian winter on the northern edge of Home Plate toward destinations of scientific interest south of the plateau. On March 10, after several attempts to get past obstacles at the northeastern corner of Home Plate, the rover team decided to switch from a clockwise route to the counterclockwise one. Subsequent events have included Spirit's longest one-day drive since the rover lost use of one of its wheels three years ago, plus detailed inspection of light-toned soil exposed by the dragging of the inoperable wheel.

Halfway around Mars, meanwhile, Opportunity has continued progress on a long-term trek toward Endeavour Crater, a bowl 22 kilometers (14 miles) in diameter and still about 12 kilometers (12 miles) away. Last week, a beneficial wind removed some dust from Opportunity's solar array, resulting in an increase by about 40 percent in the amount of electrical output from the rover's solar panels.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Science Mission Directorate, Washington.


- end -

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Re: Mars Exploration Rovers Update
« Reply #51 on: 04/16/2009 07:19 AM »
News release: 2009-067                                               April 15, 2009

Mars Spacecraft Teams on Alert for Dust-Storm Season

PASADENA, Calif. -- Heading into a period of the Martian year prone to major dust storms, the team operating NASA's twin Mars rovers is taking advantage of eye-in-the-sky weather reports.

On April 21, Mars will be at the closest point to the sun in the planet's 23-month, elliptical orbit. One month later, the planet's equinox will mark the start of summer in Mars' southern hemisphere. This atmospheric-warming combination makes the coming weeks the most likely time of the Martian year for dust storms severe enough to minimize activities of the rovers.

"Since the rovers are solar powered, the dust in the atmosphere is extremely important to us," said Bill Nelson of NASA's Jet Propulsion Laboratory, Pasadena, Calif., chief of the engineering team for Spirit and Opportunity.

Unexplained computer reboots by Spirit in the past week are not related to dust's effects on the rover's power supply, but the dust-storm season remains a concern. Spirit received commands Tuesday to transmit more engineering data in coming days to aid in diagnosis of the reboots.

After months of relatively clear air, increased haze in March reduced Spirit's daily energy supply by about 20 percent and Opportunity's by about 30 percent. Widespread haze resulted from a regional storm that made skies far south of the rovers very dusty. Conditions at the rovers' sites remained much milder than the worst they have endured. In July 2007, nearly one Martian year ago, airborne dust blocked more than 99 percent of the direct sunlight at each rover's site.

The rovers point cameras toward the sun to check the clarity of the atmosphere virtually every day. These measurements let the planning team estimate how much energy the rovers will have available on the following day. Observations of changes in the Martian atmosphere by NASA's Mars Reconnaissance Orbiter, which reached Mars in 2006, and NASA's Mars Odyssey, which reached Mars in 2001, are available to supplement the rover's own skywatch.

The Mars Color Imager camera on Mars Reconnaissance Orbiter sees the entire planet every day at resolution comparable to weather satellites around Earth.

"We can identify where dust is rising into the atmosphere and where it is moving from day to day," said Michael Malin of Malin Space Science Systems, San Diego, principal investigator for Mars Color Imager. "Our historical baseline of observing Martian weather, including data from the Mars Global Surveyor mission from 1998 to 2007, helps us know what to expect. Weather on Mars is more repetitive from year to year than weather on Earth. Global dust events do not occur every Mars year, but if they do occur, they are at this time of year."

Two other instruments -- the Thermal Emission Imaging System on Mars Odyssey and the Mars Climate Sounder on Mars Reconnaissance Orbiter -- monitor changes in airborne dust or dust-related temperatures in Mars' upper atmosphere. Orbiters also aid surface missions with radio relays, imaging to aid drive plans, and studies of possible future landing sites.

When orbital observations indicate a dust-raising storm is approaching a rover, the rover team can take steps to conserve energy. For example, the team can reduce the length of time the rover will be active or can shorten or delete some communication events.

In recent weeks, frequent weather reports from Bruce Cantor of Malin's Mars Color Imager team let the rover team know that the March increase in haziness was not the front edge of a bad storm. "Bruce's weather reports have let us be more aggressive about using the rovers," said Mark Lemmon, a rover-team atmospheric scientist at Texas A&M University, College Station. "There have been fewer false alarms. Earlier in the mission, we backed off a lot on operations whenever we saw a small increase in dust. Now, we have enough information to know whether there's really a significant dust storm headed our way."

At other times, the weather reports prompt quick precautionary actions. On Saturday, Nov. 8, 2008, the rover team received word from Cantor of a dust storm nearing Spirit. The team deleted a communication session that Sunday and sent a minimal-activity set of commands that Monday. Without those responses, Spirit would likely have depleted its batteries to a dangerous level.

Winds that can lift dust into the air can also blow dust off the rovers' solar panels. The five-year-old rover missions, originally planned to last for three months, would have ended long ago if beneficial winds didn't occasionally remove some of the dust that accumulates on the panels. A cleaning event in early April aided Opportunity's power output, and Spirit got two minor cleanings in February, but the last major cleaning for Spirit was nearly a full Martian year ago.

Nelson said, "We're all hoping we'll get another good cleaning."

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Exploration Rovers, Mars Odyssey and Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. More information about the rovers is at http://www.nasa.gov/rovers . Dust reports from the Thermal Emission Imaging System, operated by Arizona State University, Tempe, are at http://themis.asu.edu/dustmaps/. Weather reports from the Mars Color Imager team are at http://www.msss.com/msss_images/latest_weather.html.


Online jacqmans

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Re: Mars Exploration Rovers Update
« Reply #52 on: 04/21/2009 04:50 AM »
Team Continues Analyzing Spirit Computer Reboots and Amnesia Events



Mars Exploration Rover Mission Status Report

After three days of completing Earth-commanded activities without incident last week, NASA's Mars Exploration Rover Spirit had a bout of temporary amnesia Friday, April 17, and rebooted its computer Saturday, April 18, behavior similar to events about a week earlier.


Engineers operating Spirit are investigating the reboots and the possibly unrelated amnesia events, in which Spirit unexpectedly fails to record data into the type of memory, called flash, where information is preserved even when power is off. Spirit has had three of these amnesia events in the past 10 days, plus one on Jan. 25. No causal link has been determined between the amnesia events and the reboots.


The most recent reboot put Spirit back into an autonomous operations mode in which the rover keeps itself healthy. Spirit experienced no problems in this autonomous mode on Sunday. The rover team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., revised plans today for regaining Earth control of Spirit's operations and resuming diagnostic and recovery activities by the rover.


"We are proceeding cautiously, but we are encouraged by knowing that Spirit is stable in terms of power and thermal conditions and has been responding to all communication sessions for more than a week now," said JPL's Sharon Laubach, chief of the rover sequencing team, which develops and checks each day's set of commands.


During the past week of diagnostic activities, the rover has successfully moved its high-gain dish antenna and its camera mast, part of checking whether any mechanical issues with those components may be related to the reboots, the amnesia events, or the failure to wake up for three consecutive communication sessions two weeks ago.


Spirit and its twin rover, Opportunity, completed their original three-month prime missions on Mars in April 2004 and have continued their scientific investigations on opposite sides of the planet through multiple mission extensions. Engineers have found ways to cope with various symptoms of aging on both rovers.

The current diagnostic efforts with Spirit are aimed at either recovering undiminished use of the rover or, if some capabilities have been diminished, to determine the best way to keep using the rover.


Laubach said, "For example, if we do determine that we can no longer use the flash memory reliably, we could design operations around using the random-access memory." Spirit has 128 megabytes of random-access memory, or RAM, which can store data as long as the rover is kept awake before its next downlink communications session.


Offline Ben the Space Brit

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Re: Mars Exploration Rovers Update
« Reply #53 on: 04/23/2009 12:10 PM »
I know that the radiation environment on Mars' surface is harsher than on Earth because the planet doesn't have a magnetic field.  Could solar radiation eventually mess around with the chemical composition of the flash chips so that it is no longer possible to burn data onto them?

Considering that the MERs were only planned to last six months, they have managed, what, twelve times their paper lifespan? I would say that we couldn't complain if Spirit finally succumbs now.

And I still don't get, after these two were so successful, why more were not sent to Mars.
« Last Edit: 04/23/2009 12:12 PM by Ben the Space Brit »
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Offline Jim

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Re: Mars Exploration Rovers Update
« Reply #54 on: 04/23/2009 01:08 PM »

And I still don't get, after these two were so successful, why more were not sent to Mars.

Because they are limited in the instruments that they can carry.    No need to send the same instruments to other places on Mars

Offline Ben the Space Brit

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Re: Mars Exploration Rovers Update
« Reply #55 on: 04/23/2009 01:39 PM »
Because they are limited in the instruments that they can carry.    No need to send the same instruments to other places on Mars

Well, that is based on the assumption that Mars is, broadly, homogenous on a global scale and that there is thus nothing new to see (and scan) in different areas.  Has that been determined?

I accept that the MERs are small, light and limited (especially compared to monsters like MSL).  However, there is something to be said about using a lot of lighter, cheaper (in spacecraft terms) probes with which you have a degree of confidence than a single super-expensive heavyweight that you could all-too-easily shoot into the wrong place due to lack of prior data.
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Offline robertross

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Re: Mars Exploration Rovers Update
« Reply #56 on: 04/23/2009 10:21 PM »
Because they are limited in the instruments that they can carry.    No need to send the same instruments to other places on Mars

Well, that is based on the assumption that Mars is, broadly, homogenous on a global scale and that there is thus nothing new to see (and scan) in different areas.  Has that been determined?

I accept that the MERs are small, light and limited (especially compared to monsters like MSL).  However, there is something to be said about using a lot of lighter, cheaper (in spacecraft terms) probes with which you have a degree of confidence than a single super-expensive heavyweight that you could all-too-easily shoot into the wrong place due to lack of prior data.

I'd be 40-50% on that argument ben, but I'd rather see core drillers, like those planned, to get 'to the bottom' of things.  ;)

Nothing wrong having a rover slowly move around for months and years, limited to the same place +/- a few kilometers, eating up personnel time and $$ as they drove for all that time only collecting images. But Phoenix, despite its issues, provide LOTS of added science, and it was fixed. I'd rather send 2 of those again (with sample containers that worked) in different spots, too see how far the ice goes. That way you can plan for ISRU using the ice one day, although as pointed out in another thread, the use of atmospheric CO2 is more beneficial. Come to think of it, I need to respond to that thread...lol.
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Online jacqmans

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Re: Mars Exploration Rovers Update
« Reply #57 on: 04/24/2009 07:38 PM »
April 24, 2009

Spirit Resumes Driving While Analysis of Problem Behaviors Continues


Mars Exploration Rover Mission Status Report

PASADENA, Calif. -- NASA's Mars Exploration Rover Spirit drove on Thursday for the first time since April 8, acting on commands from engineers who are still investigating bouts of amnesia and other unusual behavior exhibited by Spirit in the past two weeks.

The drive took Spirit about 1.7 meters (5.6 feet) toward destinations about 150 meters (about 500 feet) away.  The rover has already operated more than 20 times longer than its original prime mission on Mars.

This week, rover engineers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., judged that it would be safe to send Spirit commands for Thursday's drive. They also anticipated that, if the rover did have another amnesia event, the day's outcome could be helpful in diagnosing those events.

Three times in the past two weeks, Spirit has failed to record data from a day's activity period into non-volatile flash memory. That is a type of computer memory where information is preserved even when power is off, such as when the rover naps to conserve power.

"We expect we will see more of the amnesia events, and we want to learn more about them when we do," said JPL's Sharon Laubach, chief of the rover sequencing team, which develops and checks each day's set of commands.

The team is also investigating two other types of problems Spirit has experienced recently: failing to wake up for three consecutive communication sessions about two weeks ago and rebooting its computer on April 11, 12 and 18. Engineers have not found any causal links among these three types of events. After checking last week whether moving the rover's high-gain antenna could trigger problems, routine communication via that dish antenna resumed Monday.

Spirit has maintained stable power and thermal conditions throughout the problem events this month, although power output by its solar panels has been significantly reduced since mid-2007 by dust covering the panels.

"We decided not to wait until finishing the investigations before trying to drive again," Laubach said. "Given Spirit's limited power and the desire to make progress toward destinations to the south, there would be risks associated with not driving."

The team has made a change in Spirit's daily routine in order to aid the diagnostic work if the rover experiences another failure to record data into flash memory.

To conserve energy, Spirit's daily schedule since 2004 has typically included a nap between the rover's main activities for the day and the day's main downlink transmission of data to Earth. Data stored only in the rover's random-access memory (RAM), instead of in flash memory, is lost during the nap, so when Spirit has a flash amnesia event on that schedule, the team gets no data from the activity period. The new schedule puts the nap before the activity period. This way, even if there is a flash amnesia event, data from the activity period would likely be available from RAM during the downlink.

Spirit and its twin, Opportunity, completed their original three-month prime missions on Mars in April 2004 and have continued their scientific investigations on opposite sides of the planet through multiple mission extensions. Engineers have found ways to cope with various symptoms of aging on both rovers.

This week, Opportunity completed drives of 96 meters (315 feet) Tuesday, 137 meters (449 feet) Wednesday and 95 meters (312 feet) Thursday in its long-term trek toward a crater more than 20 times larger than the biggest it has visited so far.

« Last Edit: 04/24/2009 07:41 PM by jacqmans »

Offline Apollo-phill

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Re: Mars Exploration Rovers Update
« Reply #58 on: 05/10/2009 12:56 PM »
The MER Spirit robot on Mars is in a precarious position currently that could ultimately hasten its end-of-mission.

It appears that it may well be 'grounded' on a number of martian pebbles with increased wheel slippage  being recorded at greater than 90% :-((

Images from Spirit show at least one wheel nearly buried by 'martian soil'.

Recent martian winds have cleared dust from solar panels leading to an increase in electrical energy available but , if it cannot be freed from its current predicament, then when the Martian winter re-appears , it could spell end of mission for this vehicle as solar panels could not be aligned to the best possible advantage positions ?


Offline Nomadd

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Re: Mars Exploration Rovers Update
« Reply #59 on: 05/10/2009 01:17 PM »
 Spirit is up to 652wh a day after the last cleaning event. That's over twice what it had at the beginning of last winter. It should be fine as long as another dust storm doesn't dump a bunch of junk on the panels before winter.
 Opportunity took six months to escape from Purgatory and her front wheels were buried pretty good for a while. Don't count Spirit out yet.
 On another note, Opportunity's front right wheel is getting worse, so the twins might be equally gimpy soon.


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