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Redstone
Back from a non-internet-connected holiday, I was surfing around and found JPL has launched the MSL website.

Here it is:http://marsprogram.jpl.nasa.gov/msl/index.html

This is a big improvement over the one page we have had for some time. Naturally, some parts need fleshing out, but there is a page for every instrument, along with summaries of the mission goals and objectives. I have not read through all of it yet, but look forward to discussion of what we can uncover here. smile.gif

And I love this picture. MSL is gonna be BIG cool.gif
Click to view attachment
deglr6328
I wonder why they're still using solid metal for the wheels instead of tires. I think in Mishkin's "sojourner" book he talks about how they were contemplating using tires even back then.
dot.dk
QUOTE (deglr6328 @ Jan 13 2006, 08:27 AM)
I wonder why they're still using solid metal for the wheels instead of tires. I think in Mishkin's "sojourner" book he talks about how they were contemplating using tires even back then.
*


You wouldn't want to get a puncture on Mars would you? huh.gif

And how would you handle the lower pressure?
Bob Shaw
QUOTE (dot.dk @ Jan 13 2006, 09:30 AM)
You wouldn't want to get a puncture on Mars would you?  huh.gif

And how would you handle the lower pressure?
*


The lower pressure issue was dealt with on Apollo 14, when the MET tyres were *deflated* relative to normal atmospheric pressure prior to launch, and once in space they 'reinflated' back to a tyre shape.

As for punctures, that's surely more of a problem - the temperatures on Mars would make many flexible materials brittle and prone to leaks, and I imagine that a nicely designed solid metal wheel could also be rather light, too.

Bob Shaw
djellison
And, to be honest, I think you could make an all metal wheel lighter than a pneumatic one. You've got to make a metal hub for the pneumatic wheel anyway, might as well make it a bit bigger and forego the risk of puncture, deflation etc.

Doug
MahFL
The in wheel suspension looks very complex, hope they can withstand the shock of landing, if this is indeed the final wheel design.
exobioquest
Ok some questions here:

WHAT! they still have not settled on a power source? Solar is still a option! that is a dam sham!

and

Does anyone want to help update: Wiki MSL

that it for now.
nprev
QUOTE (Redstone @ Jan 12 2006, 10:29 PM)
And I love this picture. MSL is gonna be BIG  cool.gif
Click to view attachment
*



Yes it is! Also from the new MSL site:

dvandorn
Yes, MSL is a good amount larger than MER. But MER, to me, is more aesthetically pleasing -- like a Lambourghini set up next to a Volvo.

-the other Doug
exobioquest
QUOTE (dvandorn @ Jan 14 2006, 10:57 PM)
Yes, MSL is a good amount larger than MER.  But MER, to me, is more aesthetically pleasing -- like a Lambourghini set up next to a Volvo.

-the other Doug
*


Or maybe it just because in this image MER is graphically illustrated with far more detail and color then MSL. tongue.gif

I think MSL will be beautiful (even if it has a MMRTG instead of a SRG) but I donít want to imagine what it would look like with solar panels, probably like a 6 wheeled volkswagen beetle with lawn chairs hanging all over its top, fing fugly!
nprev
QUOTE (dvandorn @ Jan 14 2006, 09:57 PM)
Yes, MSL is a good amount larger than MER.† But MER, to me, is more aesthetically pleasing -- like a Lambourghini set up next to a Volvo.

-the other Doug
*



Well, if they end up selecting solar power then MSL might ultimately look a lot more like a big MER...but I'll take self-contained, reliable long-term power over esthetics any day! tongue.gif

The top deck of MSL sure looks empty, though, doesn't it? This has to be an early concept drawing; all that surface real estate will surely be utilized for something!
djellison
QUOTE (nprev @ Jan 15 2006, 08:29 AM)
all that surface real estate will surely be utilized for something!
*


Take away the solar arrays, and MER's deck has the Pancam Mast, HGA, LGA, UHF, Calib Target, Mini-TES calib target and a load of hold-down-bolts. The only thing the MSL deck is missing in the drawings is UHF, LGA and Calibration targets really. It's not out of the question that the UHF might end up on top of the pancam assembly, and the LGA be forgoed alltogether. Just because there is some space there doesnt mean it has to be used for something.

I've not seen anything, anywhere, that suggests MSL WON'T be using RTG-type power and I've seen nothing anywhere that suggests is WILL be using solar power.

Doug
exobioquest
Well I'm sure the top is not going to be bare metal like that, in some of the design picture I see suspension structure and anchoring/loading points. So there going to be some bolts and texture at least.
nprev
QUOTE (djellison @ Jan 15 2006, 02:05 AM)
Take away the solar arrays, and MER's deck has the Pancam Mast, HGA, LGA, UHF, Calib Target, Mini-TES calib target and a load of hold-down-bolts.  The only thing the MSL deck is missing in the drawings is UHF, LGA and Calibration targets really.  It's not out of the question that the UHF might end up on top of the pancam assembly, and the LGA be forgoed alltogether. Just because there is some space there doesnt mean it has to be used for something.

I've not seen anything, anywhere, that suggests MSL WON'T be using RTG-type power and I've seen nothing anywhere that suggests is WILL be using solar power.

Doug
*



Glad to hear about the power source selection, Doug; there's a whole other thread running wild with speculation on that, so it's hard to separate rumor from fact.

With respect to the RTGs, then, are they perhaps slated for installation on the top deck? I can see some possible design reasons for that with respect to heat management and minimizing the use of structurally vulnerable booms, but the tradeoff would be elevating the vehicle CG...
djellison
All the design stuff I've seen has the RTG sticking out the back

Doug
RNeuhaus
Tire comparision sizes:

Click to view attachment

MSL is expected to weigh over 600 kg (1,320 lb) including 65 kg (143 lb) of scientific instruments, compared to the MERs which weigh 185 kg (408 lb) including 5 kg (11 lb) of scientific instruments. At present, MSL's mass is estimated at 775 kg (1,708 lbs).

The MSL tire is about 2.3 times wider than ones of MER and the MSL weigth is between 3.24 (600 kg) and 4.18 (775 kg) bigger than MER.

That leads to me to think that MSL will be less off-road capable than MER since the tire contact surface versus weight has been reduced for MSL in comparision to MER. I don't understand about this design. I see MER has experienced difficulties to overcome some ripples, hill and dunes and the tire design is that the tire width versus weigth must be improved.

Rodolfo
djellison
2.3 times wider, and about twice the radius - thus a 'contact patch' 4.6 times larger.

MER 185 / 6 = 30.83kg per 'unit of contact patch'

MSL (600 / 6 ) / 4.6 = 21.7kg per 'unit of contact patch'

When you mean improved - do you mean this number should go up, or down? There's arguments both ways smile.gif Up would give better traction on slopes. Down would give better driving-over-soft-stuff driveability.

DOug
RNeuhaus
Doug, Good correction. I didn't take account the tire's radius. The more surface contact is better for rocks (climb and go down) and dunes (surf) and less contact surface is better for wet lands (muds).

Now I see the improvement the off-road capability of MSL with less kg/cm^2.

Rodolfo
dvandorn
Also, MSL's wider wheel base will help its off-road driving. The further apart the wheels are, and the greater the distance between the front set and the back set of wheels, the larger a given obstacle has to be to block your path.

-the other Doug
RNeuhaus
In spite of the fact of good attack, escape and ventral angle, the height from the surface is another important matter for off-road.

The heck that I am surprised of its great weight comparing to MER. In Earth MSL weights like a Formula - 1. But, at Mars, it would weigth around (200-250 kg) along with its low speed, I seems that its off-road versability would be somewhat about the same as to the MER in spite of the fact that its wheel surface contact has improved around 30%. The reason is the greater weight.

According to my experience, the versatility of vehicle does not improve in the same proportion between the weight and wheel surface contact. In the other words, as an example, an vehicle has 100 kg and it has 4 cms^2 of wheel surface contact. The other vehicle has 200 kg and it has 8 cms^2 of wheel surface contact. Which of them is more off-road capable. I, very easy, the lighter ones will win.

I think that the heavier will need to have at least 12 cms^2 of wheel surface contact to compensate of the poor traction due to the physical land properties. It is specially most affected for sandy lands or pending slope. For a firm land, there is no matter.

Rodolfo
exobioquest
It would be nice to have some 1-2 meter wide inflatable wheels... don't think fabric science is up to it though, anybody have any info on research on inflatable wheeled rovers, I remember the tumble weed thing, but was the inflatable wheel concept rejected, disregard or forgotten?
Toma B
Nice article on Space.com:
Mars Science Laboratory

Click to view attachment
RNeuhaus
Thanks Toma for posting.

The initial targed date:

The primary MSL launch/arrival period is scheduled to extend from September 15 through October 4, 2009. That equates to a rover arrival period at Mars starting on July 10, 2010 and lasting until September 22, 2010.

While the cruise to Mars, as well as descent onto the planet mirrors past missions, the landing part of MSL is new.

Mars Science Laboratory is to use precision landing techniques, steering itself toward the martian surface similar to the way the space shuttle controls its entry through the Earthís upper atmosphere. In this way, the spacecraft would fly to a desired location above the surface of Mars before deploying its parachute for the final landing.

The above phrase seems that it is referring to Sky Crane System? Or it might be referring to a new MSL Landing module will have some kind of wings alike to Space Shuttle to maneuver the entry throught the Mar's upper atmosphere?

At present, MSL project officials donít see any full-up and costly hover tests of the Sky Crane here on Earth. Pieces of the system, like the parachute and Viking-class retro-rocket engines on the Sky Crane framework can be individually tested. "We think we can do a pretty good job of piecing it together," Cook emphasized.

I seems better that JPL must fully test the functionality of Sky Crane. It says it is not going to take as a full test but as individual test of some pieces....

Rodolfo
MahFL
Cook says MSL may last for 10 years smile.gif.
djellison
Well - look at the Viking Landers. 2000+ sols.

smile.gif

Doug
lyford
Perhaps this has been explained elsewhere, but I am having difficulty understanding the optimistic "scaling up" of the mission timeline comparing MER's 90 days = 2 years to MSL's 2 years = 10 years.

IIRC, the biggest constraint on MER was power, with the reprieve coming from unexpected dust behavior cleaning events - baring any mechanical failure or catastrophic weather, the solar powered rovers could now conceivably run until they hit their battery charge cycle limits.

But MSL is designed with a finite power source with a known rate of discharge - there won't be any free lunch boost of energy during it's mission. Or do the RTGs have some sort of "throttle" of which I am unaware? I didn't think you could power manage the same way as with MER, once it's depleted, there won't be another sunrise tomorrow to power the Mossbauer integration that you put off today.

My point is that power is no longer a wild card and since that seems to have been the factor that has contributed the most to MERs life extension, in order for the MSL engineers to be making optimistic estimates based upon primary mission requirements, there surely must be some realistic estimates on RTG life backing those statements.

Or are they saying that the RTG will last for 10 years, and hoping the mechanics last as long as well?
RNeuhaus
The thing that has short live is the material which uses the APXS or Mossbauer that are dependent of some decay material. Will the MSL use alike to them. Will the new instrument scientific last longer?

Rodolfo
djellison
QUOTE (lyford @ Jan 18 2006, 04:18 PM)
Or are they saying that the RTG will last for 10 years, and hoping the mechanics last as long as well?
*


Just the first. They will have the power for many years, and it's predictable, unlike solar arrays ( i.e. so much power they had to have afternoon sleeps with Spirit 100 sols ago, and now down to amost half that power makes long term planning hard ) Being 'around' and being 'mobile' are not one and the same smile.gif But - given lessons learnt with MER, I'm sure that they could build MSL to be certain of lasting at least 2 earth years

It's the Mossbauer that has the short halflife material and MSL has an APXS, but no Mossbauer. APXS's sample half life is, ermm, it's in the Steve Q'n'A - can't remember, but it's years and year - 20something

Doug
exobioquest
QUOTE (lyford @ Jan 18 2006, 10:18 AM)
Or are they saying that the RTG will last for 10 years, and hoping the mechanics last as long as well?
*

Well considering the history of RTGs I really don't see what there is to worry about, voyager 1&2 may last 40 years on their RTGs!, the rate of decay on a RTG is very easily calculatable. Basically 0.787% power heat watt loss per year when using Pu238 (half-life of ~88 years) also when using thermocouplers the couplers decay to, which is roughly (depending on the type of thermocouple used) double the decay rate or 1.52% electricity production loss per year. Both the MMRTG and the SRG (competing RTGs for MSL) have 14 year warranties, that means they will produce 100 watts of electricity for 14 years, how so? Well the MMRTG will start at ~125 watts of electricity at production, A ~123 by the time it reaches mars, do the calculations with excel it wonít reach 100w until 15-16 years. The SRG wonít have the decay rate of the thermocouples, but will start at a lower wattage of ~110 watts making roughly ~100 by 14 years.

MSL will likely have a battery for peak power use, that could become the major lifetime limiter.
Chmee
Add a caption:

MER: "Hey, Get out of my way, your hogging my path!"
MSL: "Don't worry, you'll stop by sunset while I'll keep going..."
biggrin.gif


*

[/quote]
djellison
That's a good point - MSL could do DTE comms at any time of day smile.gif It will never need to 'deep sleep' so that will help keep the electronics at a steady temp etc.

Doug
nprev
QUOTE (Toma B @ Jan 18 2006, 07:56 AM)


What's that linkage between the left & right suspensions that runs across the top of the deck for?

It appears as if it's meant to rotate in a plane parallel with the deck (which would explain why there's nothing mounted near it), but it doesn't look like a steering mechanism unless all the bogies can swivel in unison... huh.gif ???
djellison
Perhaps it is just part of the structure required to hang the thing from Skycrane?

Doug
mars_armer
QUOTE (nprev @ Jan 21 2006, 12:02 AM)
What's that linkage between the left & right suspensions that runs across the top of the deck for?
*

That's the differential mechanism for the rocker-bogie system. It ties the left and right rockers together so that if the left rocker pitches down the right rocker pitches up. On MER, the differential runs through the middle of the rover body and uses a gearbox. For MSL, there are no solar panels so it's simpler to have the external differential you see in the picture.
nprev
QUOTE (mars_armer @ Jan 21 2006, 09:04 AM)
That's the differential mechanism for the rocker-bogie system. It ties the left and right rockers together so that if the left rocker pitches down the right rocker pitches up. On MER, the differential runs through the middle of the rover body and uses a gearbox. For MSL, there are no solar panels so it's simpler to have the external differential you see in the picture.
*



Understood. Thanks! smile.gif

Not to sound like a critic, but isn't it a bit risky to expose this mechanism to the elements? I hope that dust doesn't accumulate in the pivot point & jam things up...or, worse, a pebble somehow gets lodged underneath... unsure.gif
PhilCo126
Items available to the General Public:
http://www.mslstore.com/

smile.gif
PhilHorzempa
Check out the MSL website to view assembly progress as the Rover enters ATLO.

http://mars.jpl.nasa.gov/msl

Now we enter a new stage in Mars exploration as a new Rover comes to life.

Another Phil





MahFL
So is that the actual MSL that will go to mars ?
dmg
[quote name='PhilCo126' date='Mar 8 2008, 11:49 AM' post='110615']
Items available to the General Public:
http://www.mslstore.com/

Does this merchandise use an official logo of the project, or is it just stuff that evokes the spirit of the mission but uses logos and artwork that is merely someone else's idea of cool?
mcaplinger
QUOTE (dmg @ Mar 28 2008, 12:55 PM) *
Does this merchandise use an official logo of the project...

I don't know if they're "official" but I see these shirts all over the place at MSL reviews.
mcaplinger
QUOTE (MahFL @ Mar 28 2008, 10:12 AM) *
So is that the actual MSL that will go to mars ?

Is what the actual MSL? The box on the right in the latest update is an actual Rover Compute Element, but I'm not sure if it's a flight unit or an engineering model. Certainly the "scarecrow" is not actual flight hardware.
djellison
There another animated gif (what the hell's with those!) which is of the flight wheels. I think they've dropped the JPL text from within the tred, but they're still 'woah - BIG' looking.

Doug
MahFL
QUOTE (mcaplinger @ Mar 28 2008, 08:38 PM) *
Is what the actual MSL? The box on the right in the latest update is an actual Rover Compute Element, but I'm not sure if it's a flight unit or an engineering model. Certainly the "scarecrow" is not actual flight hardware.


I meant is the electronic box thingy and that large aluminium looking plate part of the actual MSL that will be launched to Mars.
peter59
Mars Science Laboratory slowly materialise.
Click to view attachment
Nice view. smile.gif
ElkGroveDan
Is that a wheel or a beer keg?
peter59
QUOTE (ElkGroveDan @ Aug 27 2008, 09:03 PM) *
Is that a wheel or a beer keg?

Answer is simple.
http://mars.jpl.nasa.gov/msl/spotlight/20080307.html
ElkGroveDan
Thanks for clearing that up.
peter59
Hot off a special delivery truck from Lockheed Martin in Denver comes the aeroshell for the Mars Science Laboratory rover. Like two pieces of a giant clam, the aeroshellís backshell and the heatshield come together to protect the rover and the propulsion stage that safely delivers it to the surface of Mars. They need shelter from extreme heat caused by friction when it descends through the Martian atmosphere during landing.
Click to view attachment
Higher Res
Click to view attachment
Higher Res
I know, should be link no attachments, but I am so excited. Mea culpa.
Adam
Woah, that's big! blink.gif
peter59
Rover and descent stage stacked together (the first time and only for a moment).
Click to view attachment
Now Mars Science Laboratory site is updated once a week !
progression of 'stacking' the Mars Science Laboratory rover and its descent stage
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