I can't wait to see the higher definition videos. Also - there was quite a bit of dust being blown around there.
It will be interesting to see if there is any followup as to whether the SkyCrane maneuver is really required, or, whether in the future, we can land directly on rocket engines. Particularly with the Plutonium power supply - no need to be concerned about solar cells getting covered in dust.
Also - I seem to recall that there can be fairly significant dust storms on mars anyways - so it's not as though landing without rocket engines means that the Rover will be immune from getting struck by pebbles/rockets/dust.
A couple of people from the JPL team talked about why they used the sky crane rather than other methods and they mentioned that the amount of dust caused by using rockets all the way down would cause issues for the rover. So it seems like some dust is ok but too much would cause enough problems that the sky crane is worth it.
Might they want to minimise interference with the layers of dust/dirt on the ground, where possible? Probably not - maybe that's akin to explorers worrying about longboats pushing into the sand when they reached a beach...
They plan on driving a significant distance, so I don't think they're too worried about contamination of the landing site. I think the real issue is that they have many sensitive instruments and protecting against very small high velocity particles is difficult.
"These dust covers were one of the last things added to the rover. The MSL HazCams are build-to-print copies of the MER HazCams. On MER, the cameras were protected inside the lander, and in over 10 rover-years on the ground they haven't seen dust building up enough to be worrysome. The Skycrane system was supposed to reduce the plume ground pressure during landing to the point where dust wouldn't be an issue for MSL."
"But after Phoenix landed and everyone saw the pictures of pebbles ON TOP OF the pads on the bottom of the lander legs, and the legs themselves coated with a sticky looking layer of dust, some concerned folks looked at the issue more closely. It turned out there is a core flow in the Mars Lander Engines on the descent stage that stays strong all the way to the surface, even hanging at the end of the skycrane. And that can kick up a lot of dust+reaction products during the skycrane maneuver, some of which would go back towards the rover. There was a review of hardware in danger of being coated with "sticky" dust; everything was determined to be dust tolerant EXCEPT the HazCams."
I think it's mostly that they wanted to minimize any clouds from causing it to think it's closer to the ground than it is, and to keep the instruments from getting covered/clogged on landing.
But then the Viking landers had a full-up launch mass of 657 kg including full propellant tanks for the landing rockets.
Curiosity is 900kg just for the rover. If you added in landing rockets and their fuel as well it would be well over double the mass of a Viking lander, so the force of the landing rockets and therefore dust agitation would be commensurately greater.
Another advantage of a skycrane is that the rockets need to angled away from the payload anyway, and so the point where the plumes hit the surface is some distance from the payload, whereas rockets in the payload itself would hit the ground immediately below or to the side of it. Much closer.
It is my understanding that it is more about reducing the area that was affected by the rocket exhaust. The more area you mess up, the further you have to drive to find pristine surface. Yes, dust was stirred up over a small area, but if you took the rockets all the way down, you would disturb a much larger area, and probably change the surface chemistry around the landing site.
It does seem like there was a lot of dust kicking around. Was there anything said yet about if that was more or less dust than they expected? Maybe they don't even know how much dust is on the rover yet?
they seemed to be expecting dust on the hazcams, which i think i remember them saying (it was very early..) still had covers on them for the first shots.
Clear covers though, in case they didn't pop off as expected. Clever!
Somewhat related, and perhaps my favorite facepalm moment in space probe history: "...the titanium lens cap on Venera 14 landed precisely on the area which was targeted by the soil compression probe." (http://en.wikipedia.org/wiki/Venera#Venera_camera_failures_a...)
It will be interesting to see if there is any followup as to whether the SkyCrane maneuver is really required, or, whether in the future, we can land directly on rocket engines. Particularly with the Plutonium power supply - no need to be concerned about solar cells getting covered in dust.
Also - I seem to recall that there can be fairly significant dust storms on mars anyways - so it's not as though landing without rocket engines means that the Rover will be immune from getting struck by pebbles/rockets/dust.