Author Topic: Flying a third MER to Mars on Red Dragon  (Read 34149 times)

Offline Oersted

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Flying a third MER to Mars on Red Dragon
« on: 05/28/2016 11:34 pm »
Sorry if this has already been suggested, but I was thinking - when it was announced that a Dragon capsule would fly to Mars in two years time - that two years was actually more or less the time it took to build the two MER rovers.

The MERs have given us unrivalled science since arriving on Mars, and Opportunity is still chugging along on the Red Planet. A MER-C going to Mars with Red Dragon would surely be the best science payload one could possibly envision.

Being such a well tried and rugged design, built to take terrific g-loads during landing, should ensure that it could stand up to whatever a Red Dragon powered descent and landing could throw at it.

The know-how and perhaps even a lot of actual parts should be available at JPL for building a third rover. There is also a well-trained team for surface ops after landing.

With the actual rover design and specs well-known entities, a new package of science instruments should be less complicated to build than would be the case for a whole new rover.

I don't quite know if the folded-up MER would fit through the hatch. If that is the case only a simple deployment crane would be a necessary new-build. If not, a redesigned solar panel and/or wheel deployment design would be required. Still not nearly as complicated as making a rover from scratch, and with the creative origami skillz of JPL engineers I am sure they would be able to come up with something workable.

I think a MER-C would be the best shot at putting a really useful science payload on Mars within the super-short lead time available. Even if there isn't time to test it as thoroughly as one could wish, it would still be a very good bet for getting a tried-and-tested low-risk design to Mars on Red Dragon. I hope SpaceX and JPL can get together and explore the possibility.

Is this realistic or merely a daydream? I'd love to hear people chime in.

Offline Lar

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Re: Flying a third MER to Mars on Red Dragon
« Reply #1 on: 05/29/2016 01:33 am »
probably a daydream as it's not clear exactly how it would get out.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline biosehnsucht

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Re: Flying a third MER to Mars on Red Dragon
« Reply #2 on: 05/29/2016 05:03 am »
Will it even fit through the door, assuming you had some kind of ramp ? Or would they have to modify the capsule outer mold line just to get it through the door?

Offline Dalhousie

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Re: Flying a third MER to Mars on Red Dragon
« Reply #3 on: 05/29/2016 05:21 am »
I asked Steve Squyres about this some years ago, and he said that it has been extensively used for ground tests and is no longer in a fit state for flight.

Also keep in mind with would probably not be able to be deployed from Red Dragon without extensive mods to the later.

IMHO ;)
Apologies in advance for any lack of civility - it's unintended

Offline Oersted

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Re: Flying a third MER to Mars on Red Dragon
« Reply #4 on: 05/29/2016 09:23 am »
I am trying to find the hatch dimensions and the size of the unstowed MER.

This link (www.spacex.com/sites/spacex/files/pdf/DragonLabFactSheet.pdf) gives the size of the top and side hatches of the proposed DragonLab as:
Top hatch: 1.3 x 1.3 meters.
Side hatch: Height 0.66 m, top width 0.66 m, bottom width 0.73 m, for a diagonal of 0.91 m.
I am guessing that the Dragon 2 hatch sizes will be more or less similar.

Still haven't found the folded MER rover dimensions. However pictures such as this one makes me think that the rover might just be able to fit through either hatch:


Some things to notice:
- The front wheels are attached to a bogey which turns them from a stowed position *in front* of the instrument box and down. So the front wheels do not contribute to the overall width and height, just the length.
- The masts and solar panels on top of the box also fold down to a size not extending much beyond the sides of the rover.

As for deployment: I imagine that a telescopic pole extending and simultaneously pulling out the MER should do the trick. Guide rails inside the capsule would ensure a controlled egress. The rover is pretty hardy (remember, it was designed for multiple bounces on the martian surface). I imagine it would deal well with being lowered down the side of the capsule to the ground. Possible even from the large top hatch.

If the rover lander tetrahedron fits through the top hatch even easier: just eject it with a large spring, inflate airbags in mid-air and bounce to a stop on the surface just like MER-A and -B! :-)     
« Last Edit: 05/29/2016 09:40 am by Oersted »

Offline Oersted

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Re: Flying a third MER to Mars on Red Dragon
« Reply #5 on: 05/29/2016 09:52 am »
I asked Steve Squyres about this some years ago, and he said that it has been extensively used for ground tests and is no longer in a fit state for flight.

Also keep in mind with would probably not be able to be deployed from Red Dragon without extensive mods to the later.

IMHO ;)

Cool that you talked to Steve Squyres. He is my hero and I loved his book on the rovers!

Even though the engineering model rover has been beat up pretty much in the JPL sandbox over the years, I am guessing that the main hardware elements: the instrument box, the rocker bogey legs, maybe even the wheels, shouldn't be in a state that would make them unflyable. Even though the wheels may have some dings in them they would be perfectly serviceable: just look at the many kilometers their counterparts have rolled on Mars.

So, the "skeleton" could probably be salvaged. How many other parts and pieces would be lying in boxes around JPL? - They have a superb inventory system, as they proved when they needed to double-check some explosive bolts (I seem to remember) on Opportunity just before launch.

Could a JPL/SpaceX "tiger team" perhaps put together a MER? - Since it would just be riding along "for free" on what is basically an engineering test mission of Red Dragon it would'nt need to be tested and double-checked to the exacting stadards of the original, dedicated MER missions.

In the early days of the Falklands War RAF teams were scrounging for refuelling probes to fit onto mothballed Vulcan bombers suddenly pressed into service again. They found them on a couple of museum-piece Vulcans! - What I am imagining is just a similar shoestring budget operation. If it works, fantastic, if not, no big deal... 
« Last Edit: 05/29/2016 10:45 am by Oersted »

Offline the_other_Doug

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Re: Flying a third MER to Mars on Red Dragon
« Reply #6 on: 05/29/2016 01:13 pm »
...pictures such as this one makes me think that the rover might just be able to fit through either hatch...

That appears to be a scale model.  I once stood next to a full-sized model of a MER spacecraft (deployed).  I'm 6'1" tall, and the Pancam atop the mast was nearly exactly at my eye level.  I believe the Pancam height was designed to approximate, as closely as possible, the view a human about six feet tall would see.  The Pancam lenses are also set apart roughly the same distance as human eyes are set, again to provide stereo imaging at a human-scale depth of scene.

The model in your picture would appear to be roughly two-third to three-quarter scale.  Also, I can't see the entire model in that picture, but the part of the WEB you can see doesn't look to be the right shape.  Maybe the rover deck just isn't on there properly, I can't tell from that view.  It just looks the wrong shape...
-Doug  (With my shield, not yet upon it)

Offline Jimmy Murdok

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Re: Flying a third MER to Mars on Red Dragon
« Reply #7 on: 05/29/2016 01:44 pm »
From Wikipedia. https://en.m.wikipedia.org/wiki/Mars_Exploration_Rover
Quote
The rovers are six-wheeled, solar-powered robots that stand 1.5 m (4.9 ft) high, 2.3 m (7.5 ft) wide and 1.6 m (5.2 ft) long. They weigh 180 kg (400 lb), 35 kg (80 lb) of which is the wheel and suspension system.

They are too big.

If they know where they want the first settlement i expect them to focus on 2 small rovers working to facilite next landings

 I expect 4 wheeled crawler systems doing tasks around the spaceship: deploying panels, sensors and a big blanket with optic signs and beacons to guide next landings. Front attachment to flatten ground and remove stones...

Offline guckyfan

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Re: Flying a third MER to Mars on Red Dragon
« Reply #8 on: 05/29/2016 02:45 pm »
I would bet on a rover with a ground penetrating radar. Similar to what the chinese YUTU had. It can determine how thick the regolith cover over a glacier is. A very important information on designing water retrieval ISRU.

Offline Nascent Ascent

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Re: Flying a third MER to Mars on Red Dragon
« Reply #9 on: 05/29/2016 03:13 pm »
There's always Sojourner.  Perhaps an updated version?

Offline Oersted

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Re: Flying a third MER to Mars on Red Dragon
« Reply #10 on: 05/29/2016 04:14 pm »
They are too big.

Those are the unfolded dimensions. The rovers were much smaller inside the lander before unfolding the wheels, solar panels and masts.

The crawlers you talk about would be very cool but with only two years until lift-off it would be well-nigh impossible to construct new rovers from the ground up. That's why I am talking about using the MER architecture and all the useful hardware they would happen to have at the JPL.
« Last Edit: 05/29/2016 04:18 pm by Oersted »

Offline Oersted

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Re: Flying a third MER to Mars on Red Dragon
« Reply #11 on: 05/29/2016 04:20 pm »
I would bet on a rover with a ground penetrating radar. Similar to what the chinese YUTU had. It can determine how thick the regolith cover over a glacier is. A very important information on designing water retrieval ISRU.

That would absolutely be a great science instrument to put on a rover going to Mars!

Offline Bob Shaw

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Re: Flying a third MER to Mars on Red Dragon
« Reply #12 on: 05/29/2016 05:01 pm »
...pictures such as this one makes me think that the rover might just be able to fit through either hatch...

That appears to be a scale model.


Or a very tall man, Dougal. Seriously, though, it is a not particularly accurate model.

Perhaps the way forward would be to invite University teams to design and build a mini-MER, with similar bogie construction.

Offline guckyfan

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Re: Flying a third MER to Mars on Red Dragon
« Reply #13 on: 05/29/2016 05:10 pm »
Perhaps the way forward would be to invite University teams to design and build a mini-MER, with similar bogie construction.

I doubt anything as complex as a rover can be designed and built from scratch in that timeframe. I somewhat like the idea to invite a Lunar X-price participant to send their rover to Mars. But I expect SpaceX to have something designed and in the process of building that was not talked about yet. Maybe in September we hear more.

Offline Oersted

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Re: Flying a third MER to Mars on Red Dragon
« Reply #14 on: 05/29/2016 05:41 pm »
...pictures such as this one makes me think that the rover might just be able to fit through either hatch...

That appears to be a scale model.


Or a very tall man, Dougal. Seriously, though, it is a not particularly accurate model.

Perhaps the way forward would be to invite University teams to design and build a mini-MER, with similar bogie construction.

That's rover driver Scott Maxwell (http://www.universetoday.com/85936/in-memoriam-spirit-rover-2004-2010/) who kept a great blog about rover driving until 2012: http://marsandme.blogspot.be/

The unfolded dimensions of the MER are not too important. What would be relevant are the folded dimensions before deployment. Haven't been able to find them anywhere, which is a bit weird, given all that has been written about them.

A simple deployment device would be a telescopic mast extending out of the top Dragon hatch (which is 1.3 x 1.3 m). The mast could even be slightly curved to bring the rover out over the side of the capsule. As the mast deploys telescopically it could lift the folded rover out. When fully extended it could then lower the rover to the ground on a bridle and the rover unfolding could take place. I don't see any conceptual show stoppers... 

Offline Oersted

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Re: Flying a third MER to Mars on Red Dragon
« Reply #15 on: 05/29/2016 05:43 pm »
There's always Sojourner.  Perhaps an updated version?

Not terribly capable that one. I'd say it wouldn't even be worth the bother to bring it along. Sojourner was a technology demonstrator. The MERs were (and are) highly capable science rovers in their own right.

Offline Jimmy Murdok

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Re: Flying a third MER to Mars on Red Dragon
« Reply #16 on: 05/29/2016 06:25 pm »
They are too big.

Those are the unfolded dimensions. The rovers were much smaller inside the lander before unfolding the wheels, solar panels and masts.

The crawlers you talk about would be very cool but with only two years until lift-off it would be well-nigh impossible to construct new rovers from the ground up. That's why I am talking about using the MER architecture and all the useful hardware they would happen to have at the JPL.
Just wanted to provide some more info linked to your pic. Of course folded are small but still not enough for the hatch. I don't think would be that complex for SpaceX to make a pair of 60cm wide simple rovers designed to stay near the surroundings of the capsule. Another MER would be fantastic though.

Offline stoker5432

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Re: Flying a third MER to Mars on Red Dragon
« Reply #17 on: 05/29/2016 06:40 pm »
From what I could find, the stowed configuration width would be 48 inches (front wheel width deployed) so you would be good there. Knowing that the web height is only 14.4 inches and looking at the stowed pictures, one would presume the height would work also (the PMA folds down against the web). The length shouldn't be a problem because it could come out of the hatch face first. Of course this is all dependent on that 1.3 meter square top hatch opening being available on Dragon 2. Another big hiccup is JPL itself. Jim has already pointed out that they would see this mission as competition and would be unlikely to help much less provide a rover for it.

Offline redliox

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Re: Flying a third MER to Mars on Red Dragon
« Reply #18 on: 05/29/2016 06:54 pm »
Nice idea, but there wouldn't be time to shove it into the current Red Dragon.  And as people are saying, the hatch door isn't the correct size even for MER.  However, especially if a future Red Dragon mission is recruited to do sample return, a slightly smaller-derivative of MER could be cobbled together to make a fetch rover that could be stowed and exit through a modified hatch.

Again, nice idea but it the rover would have to be signifigantly tweaked.

An alternative comes to mind though: what if you were to instead deploy something small and aerial out of the hatch?  Such as either a balloon or helicopter drone.  Compared to either MER or MSL, those would be smaller and likely compact enough to handle the hatch, or even shot out through a device akin to a potato gun.  If you want to impress, something small that flies could be an even better idea, especially given how the helicopter idea is still viable for the current Mars 2020 rover.
"Let the trails lead where they may, I will follow."
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Offline Oersted

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Re: Flying a third MER to Mars on Red Dragon
« Reply #19 on: 05/29/2016 07:12 pm »
From what I could find, the stowed configuration width would be 48 inches (front wheel width deployed) so you would be good there. Knowing that the web height is only 14.4 inches and looking at the stowed pictures, one would presume the height would work also (the PMA folds down against the web). The length shouldn't be a problem because it could come out of the hatch face first. Of course this is all dependent on that 1.3 meter square top hatch opening being available on Dragon 2. Another big hiccup is JPL itself. Jim has already pointed out that they would see this mission as competition and would be unlikely to help much less provide a rover for it.

OK - Sounds doable then! 3 centimeters elbow room on either side through the top hatch!

I think the JPL people, engineers and scientists, would be extremely keen to use the science capability offered by a Red Dragon on the surface of Mars.

With my leet photoshop skillz I put together a little sketch of my idea:

Blue: two parallel curved telescopic mast(s), pulling out the MER while extending. (similar to lower image)
Pink: MER payload.
Red and green: Bridles.
« Last Edit: 05/29/2016 11:06 pm by Oersted »

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