That new animation is simply stunning. That felt like I was watching it live from the surface, it really did. The deployment and landing still makes me want to rush to the loo, it looks so insanely terrifying, but this is the first time I've watched that and not shaken my head in disbelief.

Fantastic job.

edit -- ah. Missed the Burns Cliff post. Nice work by the artists, Doug!

Those are balance weights. Some are jettisoned just before entry to make the aeroshell unbalanced in order to generate lift and make it steerable. This allows for a more precise landing, and was used on the Apollo Command Module. The rest of the weights are jettisoned just before parachute deploy so that the system is again balanced.

Regards,

Bob B

MSL spins during cruise- so the mass has to be ballanced.

However, for its guided entry, the centre of mass and centre of pressure need to be offset. Hence, just before hitting the atmosphere, two slabs of ballast are thrown overboard (CBM - Cruise balance mass - I'm guessing here, 2 x 75kg...HiRISE, crater? Hopefully!) )

But - before you deploy the parachute, you want to straighten up and fly right ( SUFR...no, really, they made it an acronym ) - and 6 x 25kg ballasts are thrown overboard (the bang..bang..bang..bang..bang..bang sfx)

Lots of info here : http://trs-new.jpl.nasa.gov/dspace/handle/2014/41708

If there were an excess of time and money ( something MSL doesn't have, sadly ) one could imagine a situation where those CBM's were infact DS2 like probes of some sort. Not this time, sadly.

I think I know the answer to this question before asking, but gonna ask it anyhow because it's cool: Is that attitude maneuver by the upper booster stage right after the injection burn intended to give MSL the proper angle of attack for Mars atmospheric entry? (I'm just amazed that they do it 8.5 months in advance!)

Nice.

Love the new video. 2012 can't come soon enough!

I see from http://msl-scicorner.jpl.nasa.gov/Instruments/ChemCam/ why ChemCam needs the "helmet"...

Really? Every time I watch what is planned for MSL/Killed the Cat I think,you have to be kidding. They intend this whole sequence to work without ever once trying it live from start to finish (which of course I guess they can't do given that whole pesky Earth gravity/thick atmosphere thing)? Fine, I admit it. I'm not just a glass half empty kind of guy, I figure all I'm going to get is a splash in the bottom and it will be putrid, to boot. Well, I hope they prove me wrong. I hope someone resurrects this and says, Hey Mr Pessimist, remember this post of yours from April 5, 2011? But my gut feeling is we will all be cheering on Oppy as the only Mars rover in operation for a long time to come. Oh wait, that would make me an optimist in a sense, wouldn't it? Right, forget that last part, I don't know what I was thinking.

Ask John Young and Robert Crippen about faith in extremely complex things going right the first time.

Just like Pathfinder. Just like Spirit. Just like Opportunity. Just like Viking.

I heard the MSL landing system described differently yesterday - and very well.

It's like MER...but instead of RAD solid rocket motors, it's liquid motors that can be throttled. It's a far more sensible way of putting something on the surface.

As you're convinced it's going to fail - I'd be interested to know what you think they need to do to succeed in landing an 850kg+ rover on the surface. Moreover, without falling foul of the appeal-to-authority logical fallacy - what it is that makes you think you (number of Mars landings engineered...0) know better than them ( number of Mars landings engineers - 3. PHX and MPL were LoMart, not JPL )

If you can't point at something and say 'THAT bit there, will fail'- and explain why - then you're just arm waving.

Further - yes - it might fail. That doesn't mean your pessimism without justification is in any way 'right'. If you think there's a reason why it will fail, and you understand that reason - then bring it forward.

Since the cruise stage has a propulsion system for trajectory correction, it must have some mechanism to adjust attitude for the burns. The cruise stage is spin-stabilized, and I don't recall or see how control gyros are used. So I'm guessing thrusters for attitude control. And if it has thrusters, then there is no need to orient for atmospheric entry 8.5 months early.

My guess is the orientation is to face the solar array on the back of the stage perpendicular to the Sun to maximize solar cell efficiency. Another consideration is to maximize antenna for Earth communications. The antennas are probably low-gain, omnidirectional, but even so, some directions work better than others.

That's...low. Besides, PHX worked. And I think MPL was due to FBC, it got F and C, but unfortunately, not B.

It's also accurate. The team responsible for the design, implimentation and testing of the MSL EDL system have a 3/3 record over the past 14 years.

Actually - the way TCM's are done with an MPF/MER/MSL spinner cruise stage is to not turn. You fire all four thrusters in one cluster in a pulse at some point during the rotation to adjust in that plane ( many tens of times. it's shown once in the animation) or, fire the after or fwd facing of each cluster constantly to adjust in the other 'axis'.

I wondered how on earth they did TCM's on spinning spacecraft until I met a guy from the Nav team who explained the whole process. It's very clever ( but very hard to explain with words )

At the end of cruise - they chuck the cruise stage - then use the thrusters on the descent stage ( that stick out the back of the backshell ) to despin from the 2rpm cruise spin rate and turn to entry attitude.

I may have asked this before (and if so I apologize) but does anyone know at what point (in terms of payload properties like mass & volume etc) the Pathfinder/MER approach stops being workable and an MSL skycrane becomes more suitable? Similarly, how much larger/more massive could MSL be while still using the EDL method it uses now?