MER-A status update/MER-B landing tonigh

Here's a link to the most up-to-date status:

http://www.spaceflightnow.com/mars/mera/status.html

Pretty much tells the story. Reading between the lines, they seem to have solved the most immediate problem, that is, getting it to sleep so that they end up with a positive power balance. It's supposed to sleep at night when it's not getting sun on the solar array, and the batteries run heaters to keep it going. What had been happening was that when it tried to shut down, it ran a shutdown routine, and that aborted. This is not like a desktop computer - it has to handle faults on it's own. Typically, purpose-built hardware or a simple external processor detects faults, and resets the whole comptuer to get it going again. The ability to diagnose faults and determine the appropriate action autonomously is a very, very difficult process that in many ways is far beyond the state of the art, so the logic is quite prone to not doing the ideal thing in every situation. This is true on all spacecraft that have this sort of protection, not just the MERs. In this case, on a shutdown fault, it appears to restart the machine. This is probably just what you don't want if there is a persistent hardware fault of some kind, or even worse, a software bug that show variable results depending on the conditions. The net result appears to be that the computer would try to sleep, get reset, run for a while, then try to shutdown, have another fault. on and on.

The most important thing to concern yourself with in a spacecraft anomaly is to put it into a power and thermal-safe condition. This reboot loop was preventing this, and since it didn't have enough power to run the computer all night, and still get the batteries charged the next day, the net effect being that the battery was cycling up and down in depth of discharge, with the low point getting lower and lower. At some point, the battery discharges completely at night, meaning that the heaters don't work, and everything gets cold. It may tunr on again the next day when the sun comes up, but now it's cycling up and donw in temperature - I don't know how cold it gets, but th environment is -100->-150C for 13 hours. Some parts probably stay warmer than that, but there's no doubt that the temerpature swings a lot. This fatigues the components, and eventually something will fail.

They managed to guess/determine (usually there isn't enough information to unequiviocally determine the cause of any failure, so there's an art to making good theories and guesses) that a likely cause was in the interaction with the non-volatile memory. It has regular RAM, and flash RAM to save information while the computer is off at night. That's how is stores the data overnight until it can send it back to Earth either directly or through one of the two relay satellites. It also probably is used under normal circumstances to store restart information so that it doesn't wake up like every time is the first time

What they have done is disable the use of the flash memory, and just boot up off it's EEPROM for the code/database and use the regular RAM for live storage. Now, it appears to working as expected in this "cripple" mode, and they have managed to get it to go to sleep. This is allowing the batteries to charge up and the rover now has a positive power balance. This will keep it alive. Now, the trick will be to determine how where the problem in the flash RAM process might be. It could be almost anything (to the extent I can understand it from afar just from reading the press release, and knowing a bit about the computer), from a single bad memory location, to broken interface hardware, to a bug in the software that drives the I/O.

This seems very positive. The guys working on the problem are not the cretins normally encountered on consumer tech support lines - these are experts that know the guts of the thing on a bit-by-bit and resistor-by-resistor basis. If it can be fixed, it will be fixed, and if there is any possible workaround it will be found. Keeping it alive long enough to do so was the big problem, and this seems to be well in hand.

Hate to tell ya Brett, but Richard Hoagland says that there is an upper level group sending constant 'Reboot' signals to the Rover because they have landed in a catch basic full of broken 'Relics' of a lost civilization.

Okay, I don't believe that either, just thought ya'd like to know.

For others who don't regularly listen to the Coast to Coast show, you can go to Richards website at www.enterprisemission.com

It's usually worth a laugh or three, perhaps some valium.

>Hate to tell ya Brett, but Richard Hoagland says that there
>is an upper level group sending constant 'Reboot' signals to
>the Rover because they have landed in a catch basic full of
>broken 'Relics' of a lost civilization.
>
>Okay, I don't believe that either, just thought ya'd like to
>know.
>
>For others who don't regularly listen to the Coast to Coast
>show, you can go to Richards website at
>www.enterprisemission.com
>
>It's usually worth a laugh or three, perhaps some valium.

Yes, Hoagland is a genius of the highest order. Better deadpan delivery than Bob Newhart.

But, he's far from the biggest space-related net.kook, not by a long shot. Archimedes Plutonium (who beleives that the entire universe is contained inside a single plutonium atom) is the reigning King of the Kooks, but whowever put up this site, despite being a Johnny-come-lately is definitely a worthy contender:

http://www.user.dccnet.com/vtrade/HomePage.html

I assume we are limiting ourselves to space-related kooks, because there is a whole world of kooks of other stripes - type 'Carol Paliwoda' into Google, and you'll be pleasantly surprised. OK, maybe not pleasantly.

Brett

On sci.astro.amateur, for the last few years there
was Nancy Lieder and her "Planet-X" b***s***,
Planet-X was suppossed to pass by earth on
May 15, 2003 & cause a "pole-shift." She believes
she is an emissary receiving messages from
the "Zetans." Since last May, she's been
very AWOL which is a good thing.

http://www.zetatalk.com

For some good laughs in general,
take a look at http://www.crank.net

On a more positive note, the decision to
cancel the servicing mission to the
Hubble Space Telescope might be reconsidered:

http://skyandtelescope.com/news/article_1160_1.asp

>On sci.astro.amateur, for the last few years there
>was Nancy Lieder and her "Planet-X" b***s***,
>Planet-X was suppossed to pass by earth on
>May 15, 2003 & cause a "pole-shift." She believes
>she is an emissary receiving messages from
>the "Zetans." Since last May, she's been
>very AWOL which is a good thing.
>
>http://www.zetatalk.com
>
>For some good laughs in general,
>take a look at http://www.crank.net
>
>On a more positive note, the decision to
>cancel the servicing mission to the
>Hubble Space Telescope might be reconsidered:
>
>http://skyandtelescope.com/news/article_1160_1.asp

Hey, I'll put this little tidbit on the topic of Mars against any netkook that you can find:

" Any astronomer will tell you that Mars is about 50,000 times the size of Earth. A scientist can calculate the graviton with a complex calculation as follows.

A Scientist would say, “What is the issue?”
The issue is “How does graviton relate to volume and mass in space?”
We can use calculations from the Moon & Earth. Simply put, Mars has Graviton of 10.68 times that of Earth. Simply put, Humans would last only a few minutes at most on Mars. So why didn't the Mars probe crash into the surface? The Mars probe was given a break in that the Martian atmosphere is 81% Helium and 17% Nitrogen. The parachutes did little to slow the crafts decent, however, the craft was surrounded by balloons that inflated with Air from Earth. Air is much lighter than Helium. This created enough lift to slow the decent. The heavy graviton explains why those strong robots could not endure some of those 3-4” material rocks as seen on camera from the Mars Lander Station. "

So let's see - Mars is 50000 times the size of Earth. It has 10.68 times the "graviton". The atmosphere is 81% helium, and 17% nitrogen. Air is much lighter than helium, and the lander airbags, filled with air, acted as aerostatic lift devices.

And that's just one page and a mere 13 sentences! It would be hard to pack that much BS into that amount of space if you took it as a lifetimes task.

For the record, Mars is about 1/2 the diameter of Earth (1/8 the volume). The surface gravity is about 1/3 that of Earth. The atmosphere is 95% CO2 (gaseous helium wouldn't stick around on a dare). Air on Earth is much denser than helium in the same conditions. The airbags are filled with combustion products from the pyrotechnic gas generators that actuate them, not air carried from Earth. They are much much denser than the super-thin Mars atmosphere they displace.

The "There is life at Saturn" page on that website
is priceless.

Man I almost forgot about Nancy and 'Zeta-Talk', what a bunch of hooie.

They don't require a license to be a lunatic. Then again, if they did, how would you go about revoking them?

That's good news, Brett. As I said before, miracles have been worked in the past, I'm confident if it can be worked around it will be.

A co-worker (young one) asked me what was happening with the Rover, and I said I heard it was rebooting. She quickly asked, "you mean like the Blue Screen of Death?"

"Fortunately", I told her, "it's probably not THAT serious!"..

[photo not recovered: 3e69bb3870f12ad5.jpg]

"We can lick gravity, but sometimes the paperwork is overwhelming." -Wehrner von Braun

The second lander has bounced onto the surface and is in contact with home.

Just to follow up. When I wrote the above, things looked relatively dire. Now, they are on the way to getting it going again. According to the press releases, and the second-hand information from JPL (so bear that in mind), it appears that they found or triggered a bug in the file management system that writes to the flash RAM. I got some of the information through work channels, since we are using the same operating system (VxWorks) on my project, and naturally our S/W guys were keenly interested in the details. At least ours is 4 years away from launching!

At any rate, they finally got it to turn off the flash RAM servicing, and now it's sleeping, functioning normally except for non-volatile storage, talking through the fast data links, and looks for all the world like it's going to be back in action next week.

Of course MER-B also plunked down in a miraculously good spot. I am merely a dabbler in geology, but it landed in a crater that looks like it was punched through the bedrock. There's some layered white rocks that they think might be limestone - which might have been laid down in standing water. This is of course a primary goal of the mission.

It seems to be working OK, and there are some pretty cool pictures at the site:

http://marsrovers.jpl.nasa.gov/home/index.html

I think the spaceflightnow.com website tends to be the most up-to-date, if anyone wants to follow it.

There's also a few more crank sites - like the guy who thinks he sees tiny little people (like, fractions of an inch tiny) signalling to us from the surface with a mirror and a flare, in some of the pictures.

You have to love debugging long distance. I suppose that is the advantage of manned flight. At least you're there to fix the problem. Of course, if you can't fix it, you are a long, long way from the shop.

These teams are the ultimate high-tech R/C guys on the planet!

I had the opportunity to work with a couple of Galileo team engineers while I was with Hughes--an incredible gathering of talent. It is a humbling experience just watching the live control room stuff on NASA TV.

Always looking for the little green people,

Brett,
Thanks for the update. I want to know more about the website with the little Martians with mirrors and flares. Ingenious little guys, aren't they? Got a link?

Got this off the NASA website

For Spirit, part of the cure has been deleting thousands of files from the rover's flash memory -- a type of rewritable electronic memory that retains information even when power is off.

Looks like whoever was thinking it was a windows problem might have been right. Getting rid of temporary files was always a problem with WIN95 and 98, though the 2000 version I'm running at home now generally seems to handle it well.

Anyways, looks like they are both just about ready to be going full steam again.