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

[snake_dad]

Does anyone know the different purposes they have?

Quick list, by no means meant to be complete, just to give an impression of the differences between the missions:

Beagle 2: Lander, search for signs of past or present life on the planet surface
Mars Express: Orbiter, study atmosphere and surface with radar and spectrometers
Mars Rovers: 2 Landers, search for signs of past or present water (NASA's Follow The Water strategy)
Nozomi: Orbiter, study atmoshpere and interaction with solar wind. Mission failed.

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:Question

[Glock27]

You could ask him why the landing area for the Beagle has a crater right in the middle of it.

IANANS (I Am Not A NASA Scientist), but it seemed pretty clear from the article I read. To quote:

" Scientists picked the site -- a flat, low-lying basin that's 700 square kilometres (270 square miles) in area -- to minimise natural hazards.

But, not surprisingly for a pockmarked planet, the area has a crater one kilometer (1,100 yards) wide at its center, and possibly hundreds of meters (feet) deep.

It was only revealed by close-up pictures of the site taken by another NASA orbiter, Mars Global Surveyor, minutes after the British probe was supposed to have landed last Thursday."

It does seem that they would have been better off waiting for the MGS imagery before actually landing... ;-)

Sometimes even the most obvious things are only clear with hindsight.

Re:Question

[thanasakis]

I was under the impression that there are so many probes this time because Earth and Mars came very very close last summer. Their relative position was probably favorable for plotting an easy trajectory to mars.

I could be wrong though. Could someone plz verufy this?

Re:Question

[MyHair]

I agree, but it's somewhat disturbing that the person's name is "Segfault". :-)

Re:Question

[Aglassis]

You said "It does seem that they would have been better off waiting for the MGS imagery before actually landing... ;-)

Sometimes even the most obvious things are only clear with hindsight."

This may not have been possible. Three points:
1) Mars Express was designed before the Beagle 2 was agreed to be attached. Since it had to do a correction after entering orbit to make its orbit a polar orbit, it probably wouldn't have had enough fuel to do so with the Beagle 2 still attached.
2) Since the landing area is an ellipse with the major axis parallel to the direction the craft is moving, a polar insertion would probably be unacceptable for the landing area.
3) Additional fuel would be required to decelerate the Beagle 2 out of polar orbit

Obviously since the Beagle was a late 100 kg addition, the idea of adding additional fuel is impossible due to the weight constraints. You can always wait for additional information before you attempt to land your spacecraft, but by then it might be year 3000 and the argument would be over whether the new 1 mm resolution camera is accurate enough to land a spacecraft.

I propose...

[Scoria]

... that, instead of quarreling about the legitimacy of robotic space exploration, we dedicate this thread to the inevitable development of a Mars probe drinking game!

Gallons, not liters, please...

What gives us the right?

[scsirob]

Just wondering... Suppose there *is* life on Mars, what gives us the right to drop all sorts of space junk on their planet? Let's face it, if alien probes were to crash on Earth, everyone would be up in arms...

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.

Re:What gives us the right?

[Deraj DeZine]

I would have personally brought up the whole Roswell incident as evidence of just how crazy people get over crashed alien craft.

I mean, the whole incident was probably just some teenage alien coming back from one of those underage Martian drinking parties you hear about so much and crashing his space ship. I never really saw the point in destroying the poor alien's reputation over that one little mistake. I mean, we've had him locked away in the Area 51 supermax prison for how long? It's ridiculous.

Perhaps the Martians are just holding Beagle 2 until we return that poor kid? It's about time those aliens stood up for their rights.

I for one..

[Channard]

.. am deeply disappointed by the lack of dog puns.. 'Beagle 2 fails to bark'... 'Down, Rover'.. 'Beagle 2 Space Probe has Ruff Landing'.. so much potential unfulfilled.

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:As with other airlines...

[SegFault]

04:35 Jan. 4, 2004, Universal Time
8:35 p.m. Jan. 3, Pacific Standard Time

Updated graphics

[Rxke]

Every 10 minutes another picture of the forthcoming landing:

http://mars1.jpl.nasa.gov/mgs/realtime/mera1.jpg

and http://mars1.jpl.nasa.gov/mgs/realtime/mera3.jpg

Re:Updated graphics

[Naomi_the_butterfly]

Note that's simulated, not an actual transmitted image.

When Rover lands

[maroberts]

Maybe it could sidle up to Beagle 2 and give it a push out of whatever ditch it has managed to land in!

Does Rover carry any jump leads?

One of them's BOUND to make it!

[Greyfox]

The Martians are going to run out of missiles sooner or later!

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!

They won't be in ORBIT at all.

[An Ominous Cow Erred]

...let us not forget that the Mars Rovers are scheduled for arrival in orbit this weekend.

Erm, they aren't going to arrive in ORBIT at all. They're simply going to smash straight into Mars's atmosphere without trying to orbit first. Why spend the energy (and thus propellant mass) firing engines to orbit the planet when you actually just want to GET ON THE PLANET? Mars has a thin-but-functional atmosphere that you can use to slow yourself down so you drop for a nice landing. ^_^