Mars Rovers On Final Approach

leapis writes "In the wake of the possible loss of the Beagle 2 Mars probe, let us not forget that the Mars Rovers are scheduled for arrival in orbit this weekend. As noted in this article at Space.com, the fourth and final course correction has been made, and Spirit, the first of two spacecraft, will touch down around 22:34 on 3 Jan 2004. More information and a countdown to the landing can be found here."

Comments

Question

[Sklivvz]

The article says the rover's trajectory has been updated. Is it because they were afraid it would land in a crater like beagle2?

I do hope at least one probe lands right. It is one of the advantages of having NASA, ESA and other space agencies competing, when did it happen before this that we had so many probes heading on the same planet?

Does anyone know the different purposes they have?

Re:Question

[Aggrajag]

RTFA. It appears that updating trajectory is a normal procedure when a probe approaches a planet.

"It was the fourth and possibly last time the course has been adjusted for the six-wheeled robot. Such adjustments become necessary as the craft gets closer to its destination."

And they actually trying to land it in a crater.

"Spirit is being sent to Gusev Crater, a depression the size of Connecticut that scientists believe once held a lake. It is set to land Saturday."

Re:Question

[SegFault]

Beagle2 landed at Isidis. MER-A Spirit is landing at Gusev crater. So we did a trajectory corection maneuver in order to land in a crater :)

Seriously, this is the fourth trajectory correction maneuver. We planned for up to six, but we had a pretty good initial insertion from the Delta rocket. The trajectory correction maneuvers are neccessary due to the precise angle at which we must enter the atmosphere of Mars. Too shallow and we bounce off, too steep and we make our own crater. Its like throwing a dart from Earth and having it hit a bullseye on Mars. We can't throw a dart that accurately so we control the dart on the way.

The Beagle2 and MER rovers have similar science instruments and goals. Both have several spectrometers, a mechanical arm, a rock grinder (to grind a fresh surface on the rock) and stereoscopic cameras amongst other things. Their goals are the same: Look for life or evidence that life once existed. They're also looking for evidence that liquid water was once present on the surface of Mars. The main difference is that the US built craft are mobile on the surface.

BTW, the first time 3 probes were sent to Mars (MER-A, MER-B, and Mars Express. Nozomi doesn't count since it was launched in 98) was in 1964 when the Russians sent Zond 2 and NASA sent Mariner 3 and 4. Only Mariner 4 returned useful data. Zond2 suffered a failed radio and Mariner 3 suffered a mechanical failure. (In 1962 the Russians sent 3 probes but 2 failed to reach space and the last died en route). The first successful lander was Russian, but if I remember correctly it landed in a sand storm and died before useful data could be returned.

Well, I've got to get some sleep. Got to get back to work early tomorrow to monitor the spacecraft.

--
I speak for myself. JPL and NASA can speak for themselves.

Re:Question

[SegFault]

In 1971 five different Mars-bound spacecraft were launched by the US and the USSR. Of the five, only Mariner 9 returned much useful data, to the tune of 7,329 pictures. The USSR "Mars 3" returned a few pictures and some data before it died. The other three craft failed.

Re:What gives us the right?

[sopuli]

Just wondering... Suppose there *is* life on Mars, what gives us the right to drop all sorts of space junk on their planet?

We'll just say they have weapons of mass destruction.

Celestia add-on?

[Anonymous Coward]

Does anyone know if it's possible to get accurate data from these recent Mars Probes into the Celestia 3d space simulator?

I would love to watch with my son as these craft approach and land on Mars in real time! Currently, we enjoy doing fly-bys between Mars' and moons, the ISS and Hubble, and the stars, but this would be more memorable than watching videobites after the fact on CNN. TIA.

Names

[EuroChild]

Now see, I can tell simply by the names of these probes that they will fail. By giving them these "uplifting" or "inspirational" (eg: spirit) names they are jinxing themselves. Therefore I suggest that the next probes are named things like: "dismal faliure" or "flaming wreck"...

Re:A couple of comments

[SegFault]

Mars Scorecard:

USA: 8/14 (so far, not counting MER-A and MER-B)

USSR/Russia: 4/16 (two of the four returned very little data)

Japan: 0/1

Europe .5/1 (so far, maybe the Beagle will bark)

Source: http://mars.jpl.nasa.gov/missions/log/

Better chances

[Naomi_the_butterfly]

The two mars rovers probably have a better chance of success than the (possibly) failed Beagle 2. Let's consider why:
Beagle 2 was built on a shoestring budget. Many aspects weren't tested to the extent the NASA rovers were. Example: the Beagle 2 parachute was designed in 8 weeks (as I recall; I may be a bit off here) after the original was revealed to be seriously flawed in the late planning stages. because of time constraints, the parachute was not extensively tested. It was similar with the protective balloons. On the other hand, the NASA rovers (which are virtually identical) were tested for years, every aspect tested again and again, as you can see by listening to the wonderful project scientist interviews at http://www.planetary.org/radio/ (a great group of space related radio shows.... gooooooood good stuff). The extensive testing in the NASA Mars Rover missions wasn't cheap, but there is no major flaw that engineers are 'hoping won't screw us up', unlike (possibly) Beagle 2. With enough luck (we need it, because let's face it, Mars is far away), thse 2 missions will do great. And hey, even if one fails, that's why we've got two!