I heard on the news a few weeks ago that NASA lost contact with an unmanned probe they had sent to Mars. Does NASA take the ‘shotgun’ approach with probes like this? I understand so many things can go wrong (its a pretty long trip from what I hear) but it also seems really frustrating that all those years spend working on this project and billions of dollars spent amount to some little piece of electronics being lost/burned up/exploded/etc. 
Nitpick: It was an ESA (European Space Agency) lander which has apparently failed. The first of two NASA landers landed successfully a couple of hours ago :). Also, the ESA’s project wasn’t a total failure; the spacecraft itself, which carries most of the scientific instruments, successfully entered Mars orbit. It’s the small lander deployed by this spacecraft that failed.
As for why so many probes fail, I stand by the comments I made in this GD thread:
http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=231580
In addition to the things mentioned in scr4’s thread, a lot of things - especially the landing sequence - have to be pre-programmed, and don’t allow for human input. From http://www.space.com/spacewatch/mars_progress_030808.html:
When the craft is trying to land on Mars, there is - at best - a six-minute delay in communications, so there’s no room for human corrections if something unexpected pops up. The craft could be utterly destroyed by Martian death rays, and we wouldn’t even know it until at least three minutes after the fact.
Here’s my take on it. It’s simply a matter of Martian AA gunners
doing their job. I can see one crew adding a small spacecraft emblem on the side of their gun as they hi-five each other.
Of course, they’re Martians, so they’d high-seven each other.
Achernar you know we’re not supposed to tell earthlings such things!
(Truth be known I got quite a good laugh from your reply! I LOVE great humor!)
The main reason landers fail so much is simply because it’s freaking hard to do. The Mars Spirit rover that successfully landed yesterday had to:
[ul]
[li]Ride a rocket off of the earth[/li][li]Travel for many months, cold-soaked to very, very cold temperatures[/li][li]Survive bombardment by cosmic rays from a huge solar flare[/li][li]Successfully be navigated by computer to hit a planet millions of miles away, at an angle accurate to something like 3 degrees, and a relatively small landing zone[/li][li]Fire some 37 pyrotechnic devices in a precise sequence to do things like pop parachutes, drop heat shields, inflate airbags, fire retro-rockets that have been stored for months and cold soaked, cut away the parachutes, etc.[/li][li]Fly through completely unknown weather conditions which couldn’t be predicted months in advance.[/li][li]After airbags are inflated, survive a violent impact with the initial impulse being over 40 g’s, and bouncing dozens of times.[/li][li]Avoid large rocks, crevasses, pointy things that might puncture the airbags, and rock overhangs that would block the antenna.[/li][li]After stopping, successfully roll itself upright and deploy its communication antennas.[/li][/ul]
This is a very, very difficult thing to pull off. Something as simple as coming to rest wedged between two rocks would scuttle the mission.
The fact that we can make this work at all is a tremendous achievement. We should never throw up our hands and declare the whole enterprise a failure when one of these probes doesn’t make it. We should recognize right from the get-go that these missions are very risky even when pulled off perfectly, and plan accordingly.
Incidentally, that’s exactly what NASA did with the successful Viking landers and with the current mission. Sending two identical landers to two different locations improves the chances that one will land safely and save the overall mission. The twin of yesterday’s Spirit rover, named ‘Opportunity’, arrives at Mars on Jan 24.
Aw, crap. I hate switching back and forth between vBcode and HTML. Sorry for the screwed up formatting. Maybe a mod will fix it.
Screwed up formatting fixed.
This link expands on some of the items Sam mentioned.
As he says, it is complicated stuff and everything has to happen at a very precise time.
BTW, I watched today’s NASA press conference and everything is going perfectly so far.
The Conspiracy-Buff in me says that all Mars probes have made it and are churning back clears pics of the ancient Cydonian ruins & the sophisticated technology which destroyed the habitat & sent our Martian ancestors here L
Here, FriarTed, let me just, um, fix the coding in that post…
I’d like to know why is it about this mission that is such a big deal since probes have alreay landed there and taken pictures…is it the “life on Mars” issue?? Secondly why is that such an expensive spacecraft sending back black and white pictures not color?
Freejack00, the previous Rover was a small “toy” model. These two are more like the size of golf carts and can travel in one day the distance the earlier rover traveled in its entire mission. They are truly robotic geologists.
As for the photos what you are seeing now is just initial low resolutions “snap shots” because the low gain UHF antenna is being used. You will soon see full color stereoscopic pictures with 40 times the resolution of what you are seeing now.
Be patient, the rover will not even move for 9 days.
The images from the pancam on the Spirit rover will have four times the resolution of the images we got from Pathfinder. It’s going to be glorious.
The data rate from the mission is higher as well, so we’ll get more data than we got from Pathfinder.
This rover also has a lot of scientific equipment that the Sojourner rover never had. Things like the RAT (rock abrasion tool) will allow us to grind off the old surface of a rock and peer inside. Plus, there are microscopes, mass spectrometers, and other instruments that will tell us a whole lot about the geology of the area.
There’s nothing on the rover to specifically look for life, but just knowing whether there are sedimentary rocks created by water will be a big, big deal.
Plus, we gain more knowledge about how to land on other planets through these missions which will pay for themselves when we try to do it on much more expensive missions of the future, when we drop landers on Jovian moons like Europa.
Add to all of this the success of the Stardust mission so far, and the successful arrival of the ESA Mars Express orbiter (although the Beagle lander is still MIA), and this last month has been one of the best months in the history of space science. It’ll be a capper if the Opportunity rover lands successfully in 20 more days.
I speak from experience from this one…
I’ve worked on at least nine different LEO* satellites (cheapsats as we called it then). These machines were a bear to work on, because each one had to be customized to some extent. I can tell you that the most time consuming part of satellite manufacturing is the testing. The testing started at the board level and continues all the way to the launch pad. This included not only satellite functions but environmental: shake, bake, vacuum, continuity of the wire harness, along with gobs of caffine. This is done because the AAA has chosen not to establish service above 70 miles. This is true of interplanetary propes too. Extensive testing is the only way you can be comfortable with the risks. However, not every scenario can be anticipated (witness the mars probe a few years back which was the result of one organization using the metric systems while the other used english; sounds stupid, but that’s the human nature aspect of engineering; mistakes happen.)
Being that every satellite we built was the prototype, it was amazing how many times we find a “killer” bug that could potentially cripple the satellite’s operation in orbit. As an example, a communications board we used had two problems that cancelled each other out except for a very special case that occured infrequently. Unfortunately, once that happened, you could’nt talk to the satellite anymore (once the board hung, there was no way of resetting it–this was the only board on the satellite not to have this feature. I happened to find the bug by accident, and was able to fix it pretty easily. It was a good thing too, because we used this particular board on four satellites. We had seen this bug for at least nine months and reasoned it away as a “grounding” problem (and also eliminated at least 15% of our “problem reports”).
Of the nine I worked on, five were lost because of the launch vehicle. Another one was lost when the solar panels failed to deploy (despite redundant explosive bolts) and it “starved” to death electrically. The rest continued to operate and literally run for years (exceeding their est. lifespan for 200 or 300%)
Mind you, these LEO sats were using off the shelf components and were essentially PCs placed in orbit around the earth. They didn’t do anything as complicated as the Mars Sats.
*LEO–Low Earth Orbit
My Mom asked this question (of the CNN coverage of the landing) -
What are all those people doing in the control room?
I said half of them were project managers who were there for the show, and since they are engineers there have twice as many people as needed.
Wasn’t that the Hubble Telescope? Or did it happen again?
:smack: Now why didn’t I know that??? Thanks RSA and Sam!!
Sam (or anyone else).
Thanks for the list. Your first 4 items apply to any space probe, which typically have a lower failure rate than Mars missions, AFAIK.
Elements 5-9 apply to missions that return to Earth except of course that we are using “cold-stored” materials and everything has to be automated: mission control cannot help in “real time”. Oh yeah, then there’s the unknown Martian weather.
I guess my question is a) Is there a main item that makes Martian expeditions more failure prone than others? (Is it simply that we have attempted to land on Mars while other missions only involve flybys?)