As I said - the mast would still be stowed, thus ChemCam would be hard bolted to the rover deck.

Remember - the descent stage doesn't land with the rover - it's coming down at 0.75m/sec and when the rover hits the deck it sees that off-loading as a drop in throttle level. It then cuts the cables, throttles up and flys away.

A cables-don't-cut scenario? The descent stage would, after commanding the cable cuts - work under the assumption they had cut - throttle up, pitch over 45 degrees and be out of there. I presume it would drag the rover with it and we would have a bad day.

I can't imagine a scenario where the descent stage is somehow still attached, but we have a healthy rover on the deck. If that situation were to occur (and I don't think it's actually possible) I don't think the drill or DRT could do much regarding the three ropes and the data cable. Imagine trying to cut a rope with a slow power drill. It would be near impossible on this planet - let alone on another, robotically. Plus - I'm not sure the arm could actually reach all four connection points. And - if the tethers are still on the deck in some way, trapped by the descent stage - then you couldn't deploy the mast to map the scenario and plan to use the robotic arm.

In short - a failure case I don't even think is possible, and I don't see a way out of it.

I could list probably a thousand tiny things that could go not-quite-right and cause a bad day on Mars. EDL is much like a rocket launch. When a rocket takes off, one of a thousand things could occur...and only ONE of them is good.

The Sundial base is 8cm across, and about 215 pixels across at its nearest side. Roughly 0.37mm/pixel - but at this range it's out of focus - the PSF is probably a couple of pixels across.

Aluminium's thermal expansion is about .023mm/meter per degree K. So 0.00184 mm / degree.

Given a 100 degree change - you might see something like 0.2mm change

I would doubt, very much, that it would be visible.

HiRISE will have...

Rover
Crashed Descent Stage
Backshell & Chute
Heatshield impact and debris
6 ballast mass impacts.

...to look at. It's going to be amazing

There will already be craters made by the heatshield, and the ballast masses ejected just before parachute deployment - they'll all be worth looking at and would, I'd have thought, be downrange ( east ) of the landing site by a km or 2.

The descent stage can't be aimed specifcially. It takes 4 engines to 100% and flies away at 45 degrees for 4 seconds of thrust and then falls ballistically, probably landing a very long way away. This was discussed, in length, in another MSL thread. Because it contains much organic chemistry and could potentially be and explosion risk - they will not be driving towards it for close study.

It shouldn't be too bad - they're 120 degrees apart, so passes are not close together for MERB and MSL leaving plenty of time for downlinking one vehicle before the next relay.

There's also another difference. UMSF is like the notice board in a pub. It's random, disorganized and transient.

This project at TPS is a proper catalogue.

There are more reasons that just longevity when it comes to having an MMRTG on Curiosity. Reliability for one ( 2400Whrs/sol rather than 900, then 700, then 300, then camp for winter at 200 etc etc etc ) An MMRTG also produces a lot of spare heat to keep the rover itself warm.

I call the testbed rover George - but I'm still getting used to Curiosity for the rover - and vessels of exploration are always she's - that's something Scott and I just have to disagree on

And we have 30+ years of improvements in radar, IMU's, software etc etc.

Moreover - it's not like 1.26m/sec will result in complete and utter devastation - a dinged wheel, a slightly bent suspension strut etc etc - the rover would still be able to carry on.

I'l wager the actual touchdown vertical velocity will be < 0.8m/sec

I've had a look downrange for Opportunity in whatever MOC and HiRISE images I could - but found nothing.

Most would burn up - a few small components might make it thru - but I doubt a thorough analysis has been done.

As for touchdown rates - this is interesting reading
http://trs-new.jpl.nasa.gov/dspace/bitstre...7/1/06-1785.pdf

I'm hoping we'll have a live real time feed from the live EDL visualization ( that runs of MODY bent pipe telem at about a 1hz refresh rate, + dropouts ) possibly on Ustream. I'm going to ask, anyway.

And Eyes on the Solar System should have one as a predicted simulation of events - like EPOXI and Stardust NExT.

HiRISE will be trying again to get MSL during EDL. As with PHX - it will require good planning..AND good fortune to actually get it.

I especially love the color scale used - very nice - it retains that blue 'Oh..was this an ocean??' of the low altitude, but is clearly martian above it. LOVELY work.

D

That's just a thin foam jacket around the tanks - wrapped in kapton tape. Before launch, they also got silver MLI blankets as well.

Good photo in a more finished config - here - http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA15020

The MSL descent stage MLE's are infact derived from Viking engines, but with a monolithic single large nozzle rather than a cluster of many smaller nozzles.

The Phoenix descent engines were derived from large RCS thrusters I believe (hence the pulse, not throttle) and were stolen from the '01 lander to be the orbit insertion engines for MRO and had to be replaced on PHX.

Nope - that would invoke a bunch of engineering requirements on the vehicle it just doesn't need. All we actually care about is the rover. The redundent UHF radios are in the rover itself, and the three UHF antennae used during EDL ( Parachute cone, Descent Stage and Rover ) are all driven by the rover UHF radios. The descent stage doesn't have UHF transmitters of its own

This is the MSL telecom bible - it's amazing! http://descanso.jpl.nasa.gov/DPSummary/Des...MSL_Telecom.pdf

Block diagram on Pg 44. Timeline on Pg 25

The descent stage does have X-Band transmitters - but that's simply to transmit the tones we're used to seing a-la MPF/MER. It's transmitter is 100 watts to try and hammer thru the plasma and it does so via two LGAs on the backshell (one at 17.5 degrees to account for the pitch of the capsule during entry) and the LGA on the descent stage. The rover can pick up and transmit as well, but its X-Band is only 15 watts

Several hundred meters. It depends exactly how much fuel is left at that moment, how it tumbles at burnout etc etc. There's a fairly large dispersion to it I'd expect.

With no rover to carry, and almost all its fuel exhausted - even just using 4 of its 8 engines, that descent stage is going to haul out of there.

VERY crude approximation....4 x 3060N of thrust on about 800kg of descent stage with maybe 100kg of fuel remaining.... 13.6m/s/s - so after 4 seconds it'll be at about 54.4 m/sec.

http://www.calctool.org/CALC/phys/newtonian/projectile

45 degrees, 54m/sec, gravity of 3.711. Max height is 343m, distance is 785m and it'll take 20.6 seconds ( that's assuming no drag etc)

I'd put error bars of 50% on that..but it'll be something like that.

Only change to that I know of is that the flyaway has been changed from until-depletion, to a 4 second burn. There is sufficient fuel margin to allow that to happen, and it's preferable to get that burn in, than a potential explosion in a depletion event after a burn that might be even longer.

It's not just dust. MiniTES is actually broken - it doesn't work anymore.

Someone was asking about the actual mechanism that lowers the rover under the descent stage...

http://photojournal.jpl.nasa.gov/catalog/PIA11428
http://photojournal.jpl.nasa.gov/catalog/PIA11426

On the second image the S/N001

I love the optimism that there might be cause to make as many as 999 of them

Not as optimistic as MSSS who use S/N00001
http://www.msss.com/images/science/MAHLI_PP0121_wb_cb.jpg

The sky crane phase is also very brief, just a few seconds. We intentionally made it longer in the project animation to give editors etc plenty of B-roll to use at a later date.

Just like Pathfinder, Spirit and Opportunity. Actually - they were hanging by a single thread...Curiosity will be hanging by three.

For those wondering - yes - there were tests of that deployment for MSL - here's a video of just one of them : http://www.youtube.com/watch?v=YasCQRAWRwU

A bit more video of other tests here - http://www.youtube.com/watch?feature=playe...Z-6snF0Q#t=147s

Yup - I was the technical director, the interface between JPL and the animation team. We didn't quite nail everything, but given the schedule and budget, we got pretty damn close.

Really?

Put it this way....think of MER.

Now take off the solid rocket RAD motors over which there is no control authority once ignited. Replace them with throttlable liquid engines. How different are they, really?

There was an umbilical cord between an the MER airbags and backshell. That had to be cut at the exact right moment or lander would have been dragged away by residual RAD motor thrust or have the backshell collapse ontop of the airbags.

Take the EDL timelines and put it side by side with previous ones...honestly - there are not any more phases to MSL.

Cruise stage sep. (same)
MSL has a phase here - ballast jettison.
Entry. (difference here - MSL's is guided using a lifting body design, but Vikings was 3-axis RCS as well, just without the nav algo)
MSL has another here - more ballast jettison.
Chute Deployment (same)
Heat shield sep (same)
Radar lock on the ground (same)
Backshell Sep (difference here - backshell sep on MSL is like PHX/Viking. MER's was more like the skycrane phase of MSL)
Powered decent (same as PHX and Viking. MER was very susceptible to cross winds at this phase. PHX, VIking, MSL are not. MSL, PHX and Viking can control this phase. MER's RAD motors, fired later in EDL, are solids with no adjustments once fired)
Constant velocity phase ( same as PHX and Viking)
At this moment - MER had to do DIMES imaging and airbag inflation. MSL doesn't.
Spacecraft separation ( like the MER rappelling down it's bridle from the back shell)
Mobility deploy (like deploying Viking of PHX's landing legs - at this moment in the MER timeline, it's firing the RAD motors and TIRS motors. Once fired, zero control authority on the spacecraft attitude etc)
Touchdown detection (far easier on MSL. Viking and PHX had touchdown sensors on the legs - potentially the cause of the failure of MPL. MSL just waits for the throttle to decrease on its engines to maintain constant velocity as the rover is offloaded onto the ground)
Bridle cut ( MER had this as well. It had to be timed perfectly. There is several seconds of margin for MSL here)

From this point on - VIking and PHX are safely on the ground and finished.

MER and MSL have more work to do.

MSL's Descent stage turns up the descent engines to full throttle for 4 seconds and it flys away at 45 degrees to get away from the rover.
MSL is now safely on the ground on its wheels, on the dirt. The only critical deployment left is the camera mast, probably done 2 days later which all these vehicles ( apart from Viking ) had to do.

MER however - has to conduct all of its bounces safely. Once the bounces have stopped...
Deflate the airbags
Retract the airbags
Identify which petal is face down, and begin to open the lander, righting itself if necessary.
Deploy the solar arrays.
Standup the rover using the lift mechanism.
Unfold the front wheels and lock in place. Drive the rear wheels out and lock in place.
Cut bridle to the lander
Drive off the lander (Spirit of course, had to turn around on the lander to do this)
NOW you've got the rover safely on the ground on its wheels in the dirt.

MSL has none of that to do.

Honestly - I look at the two side by side and I see MORE steps of complexity for MER. MER was far less robust, those spacecraft took massive impact G's on those bounces. A big nasty rock on any of them and it could have been game over. MSL will be the most gentle touchdown on any planetary surface in history - including Apollo. Once that touchdown is over, we're done. With MER, that just began another final phase to landing... impact to egress.

Moreover - the MSL landing ellipse has been entirely mapped, at 25cm/pixel, with 1m/pixel DTMs. MER was not. HiRISE and CRISM were not available when MER's landing sites were picked. Gale is the safest landing site we've sent a vehicle to.

I know that there's a gut reaction to the skycrane phase of MSL that make it look scary.

So was MER. We just forget how scary it was because it worked twice.

As for redundency....it's worth noting there is almost zero redundancy within each MER itself. The redundancy was two vehicles. MSL has two flight computers etc etc. There is system redundancy within it.

I worked on this : http://www.youtube.com/watch?v=P4boyXQuUIw...;feature=relmfu : as technical director for about a year. Lots of meetings with the MSL EDL team. The breadth and depth to the testing, the fidelity of simulations, the options and trade spaces they've looks at, the way they've gone about designing building and testing this system....it gives me far more confidence than I ever had for MER.

I really want to understand why people think MSL is worse than MER. So - after me saying all that - what is it that still stands out? Sorry if this comes across as bit agressively - but I really want to understand why people seem to be more scared by this than MER. It doesn't make sense to me at this point.