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Beagle 2 Failure Theories
Dan East writes "New Scientist has an article discussing the failure of ESA's Beagle 2 Lander. Theories as to why the landing failed include thinner than expected upper atmosphere, extreme atmospheric temperature fluctuations, and possible physical damage to Beagle 2 seen in an image acquired immediately after it separated from Mars Express. Recent data acquired by Mars Express, as well as NASA's Mars Rovers, are helping direct investigations into the failure. So far only around half of Beagle 2's landing ellipse has been imaged in an attempt to locate remnants of the lander. USA Today is also running an AP story on these latest theories."
My friends and I went to the NASA Ames Research Center Mars museum at Moffett Field yesterday and it was pretty cool, in a museum-for-kids kind of way. But there was one fact on display that I simply could not understand, and that the curator on duty could not help me with. I told my friend that I would ask Slashdot, where someone was sure to know, and was only joking, but now that this story has been posted (and although it's only loosely related), what the heck ...
The description of the rover module that is going to be deployed on one of the upcoming Mars missions states that it is designed to last for 3 months or until its solar panels become covered in Mars dust and it can no longer get the solar power that it needs. The question is, if they are going to send up a multi-multi-million dollar craft, why not put some simple wipers on the solar panels so that they can wipe off the dust and get some more use out of the thing?
The curator said that "five hundred people" before me had asked the same question, and that he had never been able to figure out the answer. And of course there MUST be a good reason for this; my closest guess is that the robot wouldn't last for more than 3 months anyway and so they don't bother to include the extra expense and complexity of a motorized wiper system just to keep its solar panels clean for longer than it is expected to live. But there must be a better reason than that, no?
It appears that dust covering the solar panels is only one of a number of factors which will end up rendering the mars rover a paperweight.
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The dust on the solar panels appears to be complicated by the fact that the batteries "lose capactity" and (probably most importantly) the sun moves past the latitude where the rover is located. Just like days get shorter in the winter...
I guess it doesn't matter if your solar panels are clean if they aren't being exposed to the sun for an appreciable length of time.
All of this was grossly overinterpreted from an article lean on details... http://marsrovers.jpl.nasa.gov/mission/tl_surface
The most likely candidate as an explaination of failure is simply human error. There are rarely errors in electronics that are not caused by humans that could cause such a massive loss. Usually, errors in hardware do not exist, as the hardware is top of the line and checked and re-checked for defects. (Granted, however, that sometimes faulty hardware may slip through the cracks) It is most likely something simpler than "it landed in a crater full of quicksand and sank." However entertaining it may be to picture a multi-million dollar rover sinking into the martian soil, it simply is impossible. To create quicksand one needs water. Even though the Spirit and Opportunity rovers found evidence of water on Mars, it was a long time ago, not today, that Mars was wet. So that simply is not feasible. Space debris, while a popular theory, is so unlikely (the chances of a meteor hitting something in the middle of space are *chuckle* ASTRONOMICAL) So this leaves us with simple human error. Something as simple as a single line of code can destroy an entire project (programmers know what I'm talking about). If you will remember, a few years back NASA lost a multi-million dollar spacecraft because of an error converting from the English system to the Metric system, so it is usually something tiny like that. If you asked me, it's most likely that someone typed an extra "0" somewhere in the code for orbital data and/or surface descent for the capsule. Even though it is just one "0", over that long of a distance it would make a huge difference. Remember that each decimal place is a factor of 10! Telling a spacecraft to orbit at "100,000" miles above the surface is a whole lot different than telling the spacecraft to orbit at "1,000,000" miles above the surface. Such an error would just send the poor Beagle 2 hurtling into the vast reaches of space or crashing to the surface. So it is most likely something like this that has caused all the trouble with the Beagle 2 and given those poor Brits such a hard time.
Surface pressure: 6.36 mb at mean radius (variable from 4.0 to 8.7 mb depending on season)
[6.9 mb to 9 mb (Viking 1 Lander site)]
Surface density: ~0.020 kg/m3
Scale height: 11.1 km
Total mass of atmosphere: ~2.5 x 1016 kg
Average temperature: ~210 K (-63 C)
Diurnal temperature range: 184 K to 242 K (-89 to -31 C) (Viking 1 Lander site)
Wind speeds: 2-7 m/s (summer), 5-10 m/s (fall), 17-30 m/s (dust storm) (Viking Lander sites)
Mean molecular weight: 43.34 g/mole
Atmospheric composition (by volume):
Major : Carbon Dioxide (CO2) - 95.32% ; Nitrogen (N2) - 2.7%
Argon (Ar) - 1.6%; Oxygen (O2) - 0.13%; Carbon Monoxide (CO) - 0.08%
Minor (ppm): Water (H2O) - 210; Nitrogen Oxide (NO) - 100; Neon (Ne) - 2.5;
Hydrogen-Deuterium-Oxygen (HDO) - 0.85; Krypton (Kr) - 0.3;
Xenon (Xe) - 0.08
now- from pathfinder Meteorology
It was mid-summer in the northern hemisphere of Mars when Pathfinder landed. The Pathfinder Lander is at 19.33 N, 33.55 W. The Viking 1 Lander touched down at 22 N, 50 W, 2 km below datum elevation on 20 July 1976, and is used for many of the comparisons below.
The pressures measured over the first three days average about 6.75 mb, 10% to 20% smaller than those recorded by the Viking 1 Lander during the same season 21 years ago (note that this result is consistent with the elevation difference of about 100 meters between the Mars Pathfinder and Viking 1 landing sites). The pressure showed a slight decline over the first few weeks but is now starting to rise slowly. This rise should continue through December, 1997. The pressure rise is concurrent with the slow shrinking of the southern polar cap, now at its maximum extent, as the southern winter ends.
Temperatures measured from the top of the 1 meter mast on Mars Pathfinder varied from daily highs of about 260 K (+8 F) to lows of 196 K (-107 F). This is about 10 K degrees (18 F degrees) warmer than Viking 1 Lander measurements made at 1.6 meters. The sol-to-sol temperatures have been very repeatable over the first 30 sols, and should continue until about 60 sols after landing, after which they will start to show more variation.
Preliminary wind speed estimates give late evening and early morning prevailing winds from the SSE, which shifted in the early afternoon to be from the N to NE. This is very similar to what Viking 1 found at this time of year. During the day, winds were light at only a few km or miles per hour. At night the wind speed increased to about 10 to 20 mph (16 - 32 kph) from the south.
The repeatable weather patterns of northern summer found by Viking 1 have been verified by Pathfinder so far. These include diurnal (day-night) pressure changes and semi-diurnal changes by as much as 4.5% due to atmospheric thermal tides.
Interruptions in the normal pattern of temperature drops observed on a few nights may indicate water in the atmosphere is condensing as fog. Humidity measurements are planned later in the mission.
On sol 25, temperature sampling was done at 4-second intervals for the whole day. Temperature fluctuations by 15 to 20 K (30 to 40 degrees F) were observed over minutes or seconds at some periods, suggesting turbulent boundary-layer mixing between the warmer near-surface region and cooler layers above that. A "dust devil" was also detected passing by the lander on sol 25, and later high resolution sampling has detected more dust devil signatures.
More detailed information and historical weather reports are available at the Mars Pathfinder project weather page. Raw and reduced data are available online at http://atmos.nmsu.edu/PDS/data/mpam_0001/aareadme. htm
Pathfinder used a parachute... didn't anyon notice how hard it hit? the fact that pressure and temperatures change so mu
every day http://en.wikipedia.org/wiki/Special:Random