I hope it starts transmitting data again soon. I'd hate to lose the rover this early in its mission.
I have a question about the winds on Mars. I asked this on the Oribiter forum, but I'll ask it here too.
This is probably a silly theory, but is it possible that a dust devil knocked the rover on its side? The rover looks top heavy, and those solar panels look like the perfect place for a strong wind to get a grip. The satellite photos of the area show that dust devils are constantly criss-crossing the region and with the number of them visible, it seems more likely than not that the rover will be in the path of several of these things during its 3-month lifespan.
But I'm not sure how powerful those things are or what the velocity of their winds are. I know that Mars's atmosphere is less than 1% as thick as Earth's. But does that mean that a 100 km/h wind on Mars has the same energy as a 1 km/h wind on Earth? Such a wind would not even be noticable here, let alone powerful enough to kick up a dust devil. I drove my car through a dust devil once in Southern California. It was barely visible as it crossed the freeway, but when the car went through it, you could feel it shake the car, and our ears popped like we drove up a steep hill. I'm guessing that the winds exceeded 100 km/s.
So if the winds on Mars only have 1% the energy of the same velocity winds on Earth, then maybe the dust devils on Mars are in the 1000s km/s. But that seems rather fast. I wish I knew the answer.
And if my silly theory is correct, can we just wait until another dust devel levels the rover?
Spirit has stopped transmitting data
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Topic authortony873004
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granthutchison
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Tony:
The difference is that Martian dust is much finer than terrestrial sand, so it is picked up by winds you would barely be aware of if you were standing on the Martian surface.
The force you feel from a wind is proportional to the density of the atmosphere and to the square of the wind velocity. So on Mars, with an atmospheric pressure 0.007 of Earth's, the wind has only sqrt(0.007)=0.084 the force of an equivalent windspeed on Earth. A 100km/hr Martian dust devil would feel like an 8km/hr wind on Earth - a "light breeze" on the Beaufort Scale. Even the 400km/hr of a global duststorm would measure up to only 34km/hr on Earth: a "fresh breeze".
Grant
PS: Your units have jumped the rails somewhere. If your Californian dust devil was blowing at 100km/s, it was hitting Mach 300 - I'm not surprised it shook the car!
The difference is that Martian dust is much finer than terrestrial sand, so it is picked up by winds you would barely be aware of if you were standing on the Martian surface.
The force you feel from a wind is proportional to the density of the atmosphere and to the square of the wind velocity. So on Mars, with an atmospheric pressure 0.007 of Earth's, the wind has only sqrt(0.007)=0.084 the force of an equivalent windspeed on Earth. A 100km/hr Martian dust devil would feel like an 8km/hr wind on Earth - a "light breeze" on the Beaufort Scale. Even the 400km/hr of a global duststorm would measure up to only 34km/hr on Earth: a "fresh breeze".
Grant
PS: Your units have jumped the rails somewhere. If your Californian dust devil was blowing at 100km/s, it was hitting Mach 300 - I'm not surprised it shook the car!
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Topic authortony873004
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Sorry, I meant km / hours, not seconds. That would have blown my car to Mexico. It still shook the car though. About as hard as if the car were parked and someone was pushing down on the bumper with their hands. Thanks for the math behind my question. I can rest easier knowing that the rover is not flat on its back. 
But it would only take a little bit of wind to dump a pile of dust on the solar panels.
I have to say, given that the lifespan of the rover is determined by how much time it takes for dust to collect on the solar panels, I'm surprised they didn't include a mechanism to clear it of dust. It seems like a simple blower would have done the trick.
I'm sure I'm missing something.
Tim
I have to say, given that the lifespan of the rover is determined by how much time it takes for dust to collect on the solar panels, I'm surprised they didn't include a mechanism to clear it of dust. It seems like a simple blower would have done the trick.
I'm sure I'm missing something.
Tim
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JackHiggins
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I'm watching the press conference right now on RealPlayer of NASA TV.
At the moment, they think it might be a hardware problem that has caused Spirit to go into safe mode. One item mentioned was the motor for the high gain antenna- it's thought it could be pointing in the wrong direction. Also Spirit hasn't been going to sleep at night like it should do- and it has rebooted its software over 60 times since the initial problem, in an attempt to fix itself.
There won't be any need for air blowers in future missions, because all future rovers, and landers designed to last any serious timespan, will be nuclear powered. (By RTG's) The 2009 rover will be the first to use this, after the phoenix lander in 2007/8
At the moment, they think it might be a hardware problem that has caused Spirit to go into safe mode. One item mentioned was the motor for the high gain antenna- it's thought it could be pointing in the wrong direction. Also Spirit hasn't been going to sleep at night like it should do- and it has rebooted its software over 60 times since the initial problem, in an attempt to fix itself.
There won't be any need for air blowers in future missions, because all future rovers, and landers designed to last any serious timespan, will be nuclear powered. (By RTG's) The 2009 rover will be the first to use this, after the phoenix lander in 2007/8
Not necessarily just RTGs. They're also studying the feasability of using real nuclear reactors on long deep-space missions. For example, see the Jupiter Icy Moons Orbiter program at http://www.jpl.nasa.gov/jimo/
Selden
To follow on Jack's report ...
NASA *is* receiving minor engineering information at a very slow transmission rate. This information has so far told them that power is okay, thermal is okay, and the last command in a sequence of commands to use the motor on the infra red imager mirror did not complete.
Attempts to put the Spirit "to sleep" are not working, but if the batteries get too low, it automatically goes into a "low power mode". It was stated that the batteries can be drained to dead and still be fully recharged.
Yes, there are high gain antenna problems, but of an unknown nature.
Attempts to reset the software system (computer) are not working. The Spirit has attempted 60 times on it's own. It will only go into "engineering mode" where it sends engineering data and will not load the Flight Software system.
They currently believe the problem is engineering-related (hardware, mechanical, a part, etc.) that is outside the realm of the Flight Software, thus is keeping the software from "booting".
-Don G.
NASA *is* receiving minor engineering information at a very slow transmission rate. This information has so far told them that power is okay, thermal is okay, and the last command in a sequence of commands to use the motor on the infra red imager mirror did not complete.
Attempts to put the Spirit "to sleep" are not working, but if the batteries get too low, it automatically goes into a "low power mode". It was stated that the batteries can be drained to dead and still be fully recharged.
Yes, there are high gain antenna problems, but of an unknown nature.
Attempts to reset the software system (computer) are not working. The Spirit has attempted 60 times on it's own. It will only go into "engineering mode" where it sends engineering data and will not load the Flight Software system.
They currently believe the problem is engineering-related (hardware, mechanical, a part, etc.) that is outside the realm of the Flight Software, thus is keeping the software from "booting".
-Don G.
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JackHiggins
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selden
I've read a good bit about JIMO- if it ever comes about, it'll be a fantastic mission. A fission reactor will provide FAR more power than has ever been available for deep-space missions before- letting us do radar mapping and more...
don
Good news this morning- 73mbits of data returned (all engineering, no science). While most of it was "fill" (garbage) data- they got back some data that'll help them with fault analysis too.
We know a couple more things now- it's not a HGA problem. The 73mbits was sent through the HGA, during a Mars Odyssey pass this morning. Command of the spacecraft has been regained- and engineers were able to turn it off for the night. They didn't go into low power mode last night, which is a good thing.
It could take up to 2 weeks to get back to driving the rover, and Opportunity's egress from the lander will progress more slowly, to ensure that the same problem doesn't happen again.
Guest
HGA's are the most economical way of sending back large data volumes to the NASA DSN. Am I right in thinking that laser communication isn't yet possible with spacecraft...? It's certainly on the way...
I've read a good bit about JIMO- if it ever comes about, it'll be a fantastic mission. A fission reactor will provide FAR more power than has ever been available for deep-space missions before- letting us do radar mapping and more...
don
Good news this morning- 73mbits of data returned (all engineering, no science). While most of it was "fill" (garbage) data- they got back some data that'll help them with fault analysis too.
We know a couple more things now- it's not a HGA problem. The 73mbits was sent through the HGA, during a Mars Odyssey pass this morning. Command of the spacecraft has been regained- and engineers were able to turn it off for the night. They didn't go into low power mode last night, which is a good thing.
It could take up to 2 weeks to get back to driving the rover, and Opportunity's egress from the lander will progress more slowly, to ensure that the same problem doesn't happen again.
Guest
HGA's are the most economical way of sending back large data volumes to the NASA DSN. Am I right in thinking that laser communication isn't yet possible with spacecraft...? It's certainly on the way...