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Mariner9
QUOTE (djellison @ Jan 30 2008, 04:10 AM) *
Skycrane AND Airbags AND an orbiter that gets thrown away AND a year long wait on orbit.


I don't think there is a Skycrane in the most recent ExoMars design. That word was used in the article, but I don't think it was an accurate term. The description given was of a rocket motor firing and stopping the lander 30 meters above the ground, then releasing the lander and having it drop the last 30 meters.

That is almost exactly how Pathfinder and MER landed. The Skycrane of MSL hovers over the ground and lowers the lander (gently, so they claim) to the surface.

But as for the rest of it.... I think you hit the proverbial nail on the head.

A long, long time ago a lot of us were saying that this mission was too big a jump for ESA to make from Mars Express, and that 600 million Euros was a fantasy budget. They've since wised up about the budget, but that still leaves me wondering about the wisdom of trying to jump from "orbiter derived from Rosseta" to "a mission far grander than MER".

So far the mission has slipped from 2011 - 2013. I've gotta wonder if it will slip furthur. If it does, I hope it also gets a bit more modest in scope, but I'm not holding my breath on that one.
djellison
" The last stage of the descent is performed with throttable liquid rocket engines which will compensate the horizontal wind component and stop the Descent Module in mid air, about 10 m from the ground. The Lander will then be dropped and the Descent Module backshell will fly away."

That's a liquid fueled, actively guided decent stage. Maybe it doesn't hover like the MSL decent stage (although 'stop in mid air' is a pretty accurate description of MSL) , but it's a lot more like MSL than the RAD's of the MER design.

Doug
centsworth_II
I'm confused. Are we for or against the notion that Skycrane is a name for the decent
stage as opposed to just being the name of a maneuver performed by the decent stage.
edstrick
Part of the "Skycrane" idea is lowering the lander to touchdown on a cable from the hovering crane.
The described system is more like a smart, capable, liquid fueled, horizontal velocity nulling MER backshell system than a true skycrane.
djellison
As described, it's the MSL decent stage, without a winch. It will have to tick almost all the same engineering boxes required for the skycrane manouver. It's much much closer to MSL than MER. One could argue that MSL is just a smart, capable, liquid fueled, horizontal velocity nulling MER backshell system....with a winch. The moment you decide to come to a standstill, and intelligently throttle out the cross-terrain speed, you're basically building Viking/MPL/Phoenix etc

(the hardware is decent stage, the maneuver is skycrane, although even I say skycrane in error half the time biggrin.gif )
monitorlizard
ExoMars is going through the same kind of teething pains that MSL did. Early in the planning stages, MSL was going to travel hundreds of kilometers across Mars, operating 24 hours a day, with a high degree of autonomy. It reminds me of that famous phrase "A man's reach should exceed his grasp, else, what's a Heaven for?"
djellison
QUOTE (monitorlizard @ Jan 31 2008, 01:06 PM) *
Early in the planning stages, MSL was going to travel hundreds of kilometers across Mars, operating 24 hours a day


Really? Where did you read that? I've never seen MSL described as driving at night, or driving hundreds of KM.
monitorlizard
I didn't say MSL would drive at night, I said it would operate 24 hours a day. With the RTG, the analytical instruments would have operated as well at night as during the day. However, that was in the early planning stages, I'm not sure what the current plans are.
djellison
Even at UMSF, we've had explanations as to the likely operating schedule for MSL, and it's surprising similarity to MER ( do stuff, then charge )

People may have presumed ( as I did at first ) that an RTG means it's a 24 hour science party - but it isn't - and I don't think MSL was ever actually expected to be.

Doug
ustrax
Oh Doug...You're gonna love this... rolleyes.gif


You guys are all invited, I expect heavy artillery from this side... laugh.gif
Prepare your ammunitions!

EDITED: btw, I have posted today a graphic showing the instruments to be part of the Rover, for now...
Mariner9

I had been unable to read the linked article (damn that small font and leaving my reading glasses at home) yesterday. I did not realize just how complex their proposed braking system is.

It still is not quite the MSL skycrane design, but it is a lot closer than I had imagined.

I'll concede the point, and call it a 'skycranette'.
djellison
Damn - I'm traveling at that time. I'l email you smile.gif

Thanks to Jorge for spending some weekend answering questions!!

Doug
ustrax
QUOTE (djellison @ Jan 31 2008, 07:21 PM) *
Damn - I'm traveling at that time. I'l email you smile.gif

Thanks to Jorge for spending some weekend answering questions!!

Doug


Don't confound the hours...It's from 5PM to 6PM GMT, this time... smile.gif

Mail me your questions, I'll deliver them to the man, and yes, cool of him to accept the challenge, quite a pleasant man...
ustrax
Guys...The stage is yours! smile.gif

EDITED: the man has entered with a great mood...not to waiste...
Jorge is asking for more questions..are u guys sleeping?! blink.gif

Those who haven't been there...you don't know what you have missed...

I'm converted...I'll be now an ExoMars chevalier... wink.gif
ustrax
Silly, just silly the boycott...
ExoMars will be there, that's my new Ultreya...
djellison
I just didn't have the time to get questions in before hand, and was stuck away from the 'net at the time.

Nice to see some good questions asked - I want to see the PDR before I really stake my claim. The top level questions ( MER size vehicle with MSL size payload - no relay capacity - the year long wait on orbit ) didn't get covered - but some good stuff did. I still don't think it's the right mission for ESA to be doing at the moment - I think it could spend that much money better elsewhere.

I don't think anyone's boycotting, don't be offended, I just think people still don't think of ExoMars as a real mission yet - I find it hard to - and until the minsters meeting later in the year - it is just a proposal and a study. That it will progress to a real mission is by no means certain.

Massive thanks to Jorge for answering questions!

Doug
ustrax
Offended?! blink.gif
Man, you got me wrong, I wasn't saying people were boycotting here, man...almost all the guest came from here... ;-)
I was making reference to the fact of Jorge Vago, asked us for, please, telling our governments that there is this one really cool mission at ESA that requires their support and attention at the 2008 ESA Ministerial Conference.
This sounds to me me like these governments haven't been giving a special attention to this mission...That's the boycott I was referring to, knowing from other sources that some instruments are having hard times trying to reach somewhere...

In the meanwhile...here's a spacEurope (EDITED...) pseudo-exclusive... tongue.gif
ExoMars rover has you have never, sort of, seen it! smile.gif
djellison
Carefull of using the word 'exclusive'
http://www.esa.int/esa-mmg/mmg.pl?mission=...on&subm3=GO

smile.gif

Doug
ustrax
Exclusive? Who used the word exclusive?... tongue.gif
I hadn't seen that yet...

EDITED: But mine as something exclusive regarding that one Doug...the drill was operating... wink.gif
Tom Tamlyn
Apparently ExoMars needs a new name.

TTT
ngunn
QUOTE (Tom Tamlyn @ Feb 10 2008, 04:31 AM) *
Apparently ExoMars needs a new name.

TTT


Sounds like 'ExtraMars' might fit.

Good news in that article about increased British commitment to ESA. Not before time.
Stu
QUOTE (ngunn @ Feb 10 2008, 09:00 PM) *
Good news in that article about increased British commitment to ESA. Not before time.


Funding problems for UK ExoMars science

Here we go... (sigh)...
spdf
I hope noone did ask this question before. Since it would be probably too late for MSL, would it be possible for ExoMars to carry the DS 2 penetrators to Mars? With as little as possible extra work and money. Or would be 12 extra kilos too much?
djellison
12 kilos probably wouldn't be a cruise stage problem. HOWEVER - if Exomars enters orbit before deploying, then you've also got to de-orbit the DS2's, and err..

you've got to fund, design, test, build two DS2's....without any money.

Doug
Marz
I wonder if sampling problems from Phoenix are going to necessitate a redesign of how the Pasteur drill on Exo must deliver samples? Could the Mole also encounter problems depending on the soil characteristics; it seems like dunes in Meridiani can be fluffy and fluid, while the soil at the poles is clumpy and cohesive?
Stu
French propose downsizing ExoMars...

http://www.space.com/news/090130-sn-france...s-concerns.html

Surprised? Moi? sad.gif
tedstryk
QUOTE (Stu @ Feb 1 2009, 03:00 PM) *
French propose downsizing ExoMars...

http://www.space.com/news/090130-sn-france...s-concerns.html

Surprised? Moi? sad.gif


I don't think it is a bad idea if it means it will actually get built instead of always staying 7 or 8 years in the future.
Stu
QUOTE (tedstryk @ Feb 1 2009, 02:33 PM) *
I don't think it is a bad idea if it means it will actually get built instead of always staying 7 or 8 years in the future.


Me neither, and it might well be the reality check the mission needs, but I just can't shake this gut feeling that it's never going to reach Mars. I don't like the feeling, and I desperately hope I'm wrong, but with this project rapidly taking on the shape of a political hot potato - or croissant wink.gif - and with the current financial situation, I fear ExoMars is already feeling the downdraught of circling vultures' wings on its solar panels.

djellison
MER sized vehicle with an MSL sized payload in an untested landing system. I never have, and doubt I ever will like the concept of ExoMars unless it gets a significant architecture change.
ngunn
That opens up an interesting question. How would knowledgeable members here go about that mission re-design? I'm sure a number of individual members will have good suggestions - maybe there could even be a collective effort leading to a UMSF shadow-proposal? (Or maybe ustrax will dust off his trusty crystal ball and just tell us how it's going to be? smile.gif )
djellison
EU lead exobiological payload, US remote sensing instruments, using a deep-drill on a pallet lander delivered by an MSL derived descent stage launched on an Ariane 5.

OR

Scrap the whole thing and do netlander / metnet with a European orbiter.




helvick
I'd go with Doug's second option - it has a higher likelihood of success, has some redundancy, builds capabilities not planned elsewhere and provides a practical stepping stone for ESA to consolidate actual lander experience for an extended period of time while working on developing more advanced capabilities like deep drilling, sample return, ballons\micro gliders or whatever your chosen next gen rocket science tech might be.

Do this right and they are in a strong position to get increased funding in future by having a proven track record, do it wrong and the distributed nature of ESA's funding and control will make it very hard to follow on with more advanced landers on Mars or elsewhere.
SFJCody
Both these ideas are sound. I always wondered why things swung away from deep drills and netlanders and towards more rovers. Surely not a bandwagon jumping response to the success of MER?
Mariner9
I have always assumed that ESA moved away from the netlander concept and went with a rover because the US had flown MER. (I suspect that was what you were getting at.)


And as we have discussed on this board for a long time now, the mission has always suffered from either an overly optimistic low-ball budget, or an over-ambituous architecture, frequently both.

I'm glad to see the French pushing for some down-sizing. Better a modest mission that suceeds, versus a kick-ass mission that either fails or never even leaves the launch pad.

It is especially welcome now that the US has announced that it is interested in collaborating on the 2016 mission. I was afraid that the US technical contribution (roughly in the 400 million dollar range) might encourage the mission planners to keep thinking big. Or worse, even expand the scope.


djellison
$400M. That's a nice big orbiter. EU provides a netlander like payload. Nice clean interfaces for ITAR. Brilliant. We need 400kg of paylod for 3x 100kg landers, 3 x Metnet landers, and the associated bolt-on-hardware.
Mariner9
I think that is a reasonable scenario. I would like to see something like that happen.

What worries me is that some people could see the $400 million and say "Great! Now we can do the big rover the way we wanted to all along, and add the telecommunications orbiter to it that we've been wanting."


Hopefully pressure from the French, and other sane heads, will prevail.

vjkane
QUOTE (djellison @ Feb 2 2009, 09:45 AM) *
$400M. That's a nice big orbiter. EU provides a netlander like payload. Nice clean interfaces for ITAR. Brilliant. We need 400kg of paylod for 3x 100kg landers, 3 x Metnet landers, and the associated bolt-on-hardware.

$400M is light for a Mars orbiter. MAVEN is ~$450M. Mars Science Orbiter is ~$1.1B. The estimated cost by NASA for a 4 node network mission is ~$1.2B (not including an orbiter). The capabilities of the landers wasn't specified, but the general idea is a seismic station, meteorology, heat flow, and high bandwidth (seismic data is voluminous). More cut rate versions of the stations could be done. The Finnish MetNet, for example, should be much cheaper (if they work), but they would lack the high bandwidth for high value seismometry.

The orbiter should have meteorology instruments and a wide angle camera for monitoring the atmosphere. It could be done for $400M, but I don't know if that would pay for an orbiter in a low orbit ideal for communications.
Paolo
There is a nice article on ExoMars on the May issue of AIAA's "Aerospace America"
Stu
BBC reports "Europe's Mars mission scaled back"...

http://news.bbc.co.uk/1/hi/sci/tech/8102086.stm

tedstryk
A U.S. launch vehicle? Didn't see that one coming.
Juramike
Bummer about the loss of seismic and meteorology package (Humboldt payload)

Joint NASA/ESA mission is a very good thing.

Drill, baby, drill!
tedstryk
Humbolt did seem an odd package for a rover.
helvick
I'm also disappointed by the descoping of Humboldt but I'm reading very positive things into this - I'm getting a much stronger impression that she's actually going to fly now.
djellison
When is ESA going to learn that the mission is should be doing is Netlander. Grrrrr.
hendric
Preaching to the choir, Doug. Maybe the Chinese or Indians will decide to do this. It's "relatively" easy with a great science return.
Juramike
Hopefully the development work done on the Humbolt science package could be multiplied for a network system.

N(Humbolt) = Science^N
AndyG
The future seismology side of things is covered in the BBC article.

QUOTE
"I'm absolutely confident we will see the elements of the Humboldt payload eventually deployed on Mars, but probably in a more dedicated circumstance," explained Professor Southwood. "For instance, instead of having one stationary station, is it not better if you are looking at an entire planet to have multiple stations?"


...bit of a no-brainer, but I suppose once the ESA have successfully proved a system that can deliver packages to the Martian surface, it will eventually follow.


jsheff
It looks like they're serious about NASA/ESA cooperation, and are thinking about a joint launch of ExoMars and the Mars Science Orbiter in early 2016 on an Atlas 5:

NASA poised to join Europe's Mars Rover Mission

- John Sheff
Cambridge, MA
monitorlizard
An interesting article, but I don't quite see how the arrangement they describe is possible. The U.S. Mars Science Orbiter's projected funding is already so tight that a HiRISE-class imager has been dropped from the baseline payload. Carrying ExoMars in the same launch means a larger, more expensive rocket. It's a nice idea, but this would cost the U.S. more money, not save money (by combining U.S. and European missions) as I have previously read.

BTW, the article got one thing wrong. U.S.-built nuclear heaters are not called radioisotope thermoelectric generators, they're known as radioisotope heater units (RHUs).
remcook
From what I remember, ESA is planning to pick up some of the orbiter's bill (some instruments I think) and NASA would pick up some of the bill for the launch window after it. But I could be wrong. Anyone else know more about this? I think launcher is Atlas 5...
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