NASA Selects Landing Site for Phoenix Mars Lander

Earlier this week, NASA made a course adjustment for its Phoenix Mars Lander which puts it on a path to land in "Green Valley" on the Red Planet late next month. The site was chosen for being a broad, flat expanse that is relatively free of rocks capable of damaging the lander when it sets down. The location will be confirmed pending further reconnaissance from an orbiting satellite. The probe's mission, which we've previously discussed, is to investigate subsurface ice. "The landing area is an ellipse about 62 miles by about 12 miles (100 kilometers by 20 kilometers). Researchers have mapped more than five million rocks in and around that ellipse, each big enough to end the mission if hit by the spacecraft during landing. Knowing where to avoid the rockier areas, the team has selected a scientifically exciting target that also offers the best chances for the spacecraft to set itself down safely onto the Martian surface."

Comments

Ironic

[calebt3]

We land these things in rock-free regions so that they can look at rocks.
(Yes, I know this one is looking for ice)

Re-Name That Lander

[Anonymous Coward]

In other news today, NASA announced that the Phoenix Mars Lander will now be called the Firebird Mars Lander.

UPDATE: Make that Firefox Mars Lander.

Need to think of other ways of landing

[NorbrookC]

At some point, it might be useful to think of other methods of landing probes. Not all of the scientifically interesting areas are going to be near easy-to-land on sites, free of large rocks or unexpected features. In order to get to them, probes are going to have to land on rough terrain, or be able to move there. Which ought to pose some nice challenges for the engineers designing these probes.

Re:Need to think of other ways of landing

[Anonymous Coward]

Yeah, but rovers are more expensive. The Phoenix lander was one of NASA's throwaway missions (the Mars Scout missions). They didn't throw in all the bells and whistles nor did they expect a 100% chance of success. It was launched because it was cheap and there is a moderate chance of success. If it fails it won't be a big deal since it was cheap. At least that is the logic behind it.

I'm not sure I agree with this philosophy. It sounds good on paper but we need to remember what happened to the Mars Polar Lander, part of Dan Goldin's Better-Faster-Cheaper program. I think we all remember how that program worked. It seems to me that the Phoenix lander is just another Better-Faster-Cheaper probe. I hope it doesn't die like many of the others. I like the idea of getting science on the cheap, but the engineer in me is extremely skeptical.

Re:Need to think of other ways of landing

[ceroklis]

You should apply to the JPL, I'm sure they never thought of that.

• http://marsprogram.jpl.nasa.gov/msl/technology/tech_edl_mardi.html
• http://www-robotics.jpl.nasa.gov/applications/applicationArea.cfm?App=3
• http://www-robotics.jpl.nasa.gov/tasks/showTask.cfm?FuseAction=ShowTask&TaskID=84&tdaID=999986
• http://www-robotics.jpl.nasa.gov/publications/Andrew_Johnson/aejJGCD2002.pdf

Re:Need to think of other ways of landing

[SegFault]

Phoenix is a re-fly of MPL using flight-spare MPL hardware. The difference is that since the spacecraft and instruments were already on the shelf, there was relatively more budget for the kind of investigation, review, and rework that the original mission should have had. As a result, we've identified and fixed a sobering number of fatal errors in the original design.

The disposition of the team at this time is "cautiously optimistic", which is more confidence than we had on MER at the same time. That said, there is always residual risk and the chance of just having a bad day.

Let's hope this time...

[hyades1]

...they come up with a good answer to that single most important question: "Will that be metric or imperial?"

Re:Let's hope this time...

[SegFault]

Considering that Phoenix is a re-fly of the 1998 Mars Polar Lander mission, this was the subject of an intensive study of the command dictionary, flight software, and ground software.

Please remember that the 1998 MPL and MCO missions were part of NASA's "Better Faster Cheaper" movement. These were budget class missions that exchanged significantly increased risk, in the form of less internal and external oversight and review, for significantly lower cost. The problem is that landing on another planet is a very hard problem, especially Mars. This mission carried "flagship" mission difficulty (ala MER) but wasn't given the budget to address anywhere near all the higher order risks. Keep in mind the atmosphere on Mars is too thick to use retro rockets all the way to the ground, like on the Moon, and too thin to use parachutes all the way down, like we have done on Earth. Also keep in mind that MPL and Phoenix missions use a landing system which is closest to a system that we hadn't flown in over 20 years (Viking). And it was chosen primarily for budgetary not technical reasons. I'm not even going to get started with the landing radar...

The kinds of errors that killed MPL and MCO were exactly the kinds of risk that NASA bought by forcing the budget low. They purchased a mission with flagship risk on a budget that precluded mitigating those risks.

Phoenix is a three-quarter measure to fix the errors of MPL. It's a re-fly of the 1998 MPL mission with the kind of oversight and peer review that the original mission would have had if it were designated the kind of budget that it deserved. The results of these ongoing studies have led to numerous design changes in hardware, radar firmware and antenna design, flight software, and fault protection. The team at Lockheed and JPL is cautiously optimistic.

Breaking news...

[g0dsp33d]

An anonymous engineer at NASA stated that the landing site will be in the Arizona desert just outside of Phoenix, hence the lander's name.