Author Topic: How many Opportunity Rovers could Falcon Heavy fly to Mars?  (Read 4969 times)

Offline whitelancer64

How do you get rid of the expensive plutonium heaters in a fully electric design? ???

No plutonium in the MERs. That is Curiosity.

The MER rovers have 8 Radioisotope Heater Units with about 3 grams of Plutonium 238 each.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
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Offline Oersted

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #21 on: 05/10/2017 04:30 PM »
SpaceX is not focused on Mars to satisfy the science community. They are in it for colonization. Obviously, down the road, Mars colonization will hugely benefit the science community. Specifically there will be huge amounts of sample return.

If MERs were to fly to Mars on a Falcon Heavy they would go with instruments to characterise soil, rock and water.

Do anyone see a better, cheaper and faster way to surface-reconnoiter colony candidate sites?

Yes. Build a clean-sheet, customized design for the purpose, rather than make a kludge with obsolete parts and designs.

"Clean-sheet" and "customised" certainly sounds better, but not cheaper and certainly not faster.

SpaceX has a huge amount of work on their plate. I think it won't hurt them to outsource some of it, and then why not outsource to the undisputed leaders in the field of Mars exploration, the JPL?

A cooperation with the JPL around MER-based reconnaissance rovers will also be a huge boon for SpaceX as regards knowledge-transfer about Mars.

"We offer the delivery to Mars and together we cooperate on site-selection and the construction of rovers".. - Would JPL turn down such a deal?

Offline Oersted

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #22 on: 05/10/2017 04:34 PM »
How do you get rid of the expensive plutonium heaters in a fully electric design? ???

No plutonium in the MERs. That is Curiosity.

The MER rovers have 8 Radioisotope Heater Units with about 3 grams of Plutonium 238 each.

Ah yes, I stand corrected, I had forgotten about those small heaters.

Online rakaydos

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #23 on: 05/10/2017 05:16 PM »
Is there anything fundamental keeping a rover from being designed with low temperature stable electronics? It would certiantly complicate testing, launch and transit if it has to be shipped to mars in a refrigerator, but a rover that doesnt need to warm itself up at night might have certian benifits.

Offline Phil Stooke

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #24 on: 05/10/2017 05:23 PM »
The batteries are at least as needy as the electronics when it comes to keeping warm.  Are there now any low temperature batteries which could replace the MER battery design?

Offline whitelancer64

If the temperature were stable, that would be no problem. There are plenty of low-temperature rated parts out there. The issue is thermal variance. It's roughly a 100 degree C swing between day and night temperatures on Mars, that will cause expansion and contraction, leading to broken parts.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Online Dao Angkan

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #26 on: 05/10/2017 05:46 PM »
SpaceX is not focused on Mars to satisfy the science community. They are in it for colonization. Obviously, down the road, Mars colonization will hugely benefit the science community. Specifically there will be huge amounts of sample return.

If MERs were to fly to Mars on a Falcon Heavy they would go with instruments to characterise soil, rock and water.

Do anyone see a better, cheaper and faster way to surface-reconnoiter colony candidate sites?

Yes. Build a clean-sheet, customized design for the purpose, rather than make a kludge with obsolete parts and designs.

"Clean-sheet" and "customised" certainly sounds better, but not cheaper and certainly not faster.

SpaceX has a huge amount of work on their plate. I think it won't hurt them to outsource some of it, and then why not outsource to the undisputed leaders in the field of Mars exploration, the JPL?

A cooperation with the JPL around MER-based reconnaissance rovers will also be a huge boon for SpaceX as regards knowledge-transfer about Mars.

"We offer the delivery to Mars and together we cooperate on site-selection and the construction of rovers".. - Would JPL turn down such a deal?

Or cooperate with ESA to make a duplicate ExoMars rover bus. They'd still run into the RHU issue though, even more so as Russia is supplying it. A 2-metre drill might be handy for regolith ice collection if they want to perform some ISRU experiments.
« Last Edit: 05/10/2017 05:49 PM by Dao Angkan »

Offline Kaputnik

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #27 on: 05/10/2017 07:29 PM »
I'd imagine an in-house SpaceX Mars rover would throw mass at the problem, and just have larger solar arrays with electric heaters
They would probably also use a Dragon as the starting point for the landing vehicle, rather than try to duplicate NASA's design, which relies on some very specialsed technology.

(Note- NASA developed a Mars EDL architecture in the 70s for Viking and has reused it every time since then. Same cone/sphere heatshield shape, same disk-gap-band supersonic parachute. Only the terminal landing sequence has been altered, to suit each mission).
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Offline whitelancer64

I'd imagine an in-house SpaceX Mars rover would throw mass at the problem, and just have larger solar arrays with electric heaters
They would probably also use a Dragon as the starting point for the landing vehicle, rather than try to duplicate NASA's design, which relies on some very specialsed technology.

(Note- NASA developed a Mars EDL architecture in the 70s for Viking and has reused it every time since then. Same cone/sphere heatshield shape, same disk-gap-band supersonic parachute. Only the terminal landing sequence has been altered, to suit each mission).

Not so, the EDL hardware designs were similar, but not the same.

The MER heat shield was a different size and the backshell had a different geometry than the Viking landers, for example. Also the parachutes for the MER program were smaller and had to be extensively redesigned - early testing had squidding and tearing problems, with one parachute shredded completely.

Curiosity was heavier than the Viking landers and so had a larger parachute, backshell, and heat shield (which was made of PICA).
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline synchrotron

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #29 on: 05/10/2017 08:13 PM »
I'd imagine an in-house SpaceX Mars rover would throw mass at the problem, and just have larger solar arrays with electric heaters
They would probably also use a Dragon as the starting point for the landing vehicle, rather than try to duplicate NASA's design, which relies on some very specialsed technology.

(Note- NASA developed a Mars EDL architecture in the 70s for Viking and has reused it every time since then. Same cone/sphere heatshield shape, same disk-gap-band supersonic parachute. Only the terminal landing sequence has been altered, to suit each mission).

The disk-gap-band parachutes have undergone considerable redesign for the later missions. While the Viking data was and is invaluable, the dynamics of the EDL can vary considerably depending on the mission. In general, most re-use in exploration spaceflight is know-how rather than designs.

Offline Kaputnik

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #30 on: 05/10/2017 08:15 PM »
I'd imagine an in-house SpaceX Mars rover would throw mass at the problem, and just have larger solar arrays with electric heaters
They would probably also use a Dragon as the starting point for the landing vehicle, rather than try to duplicate NASA's design, which relies on some very specialsed technology.

(Note- NASA developed a Mars EDL architecture in the 70s for Viking and has reused it every time since then. Same cone/sphere heatshield shape, same disk-gap-band supersonic parachute. Only the terminal landing sequence has been altered, to suit each mission).

Not so, the EDL hardware designs were similar, but not the same.

The MER heat shield was a different size and the backshell had a different geometry than the Viking landers, for example. Also the parachutes for the MER program were smaller and had to be extensively redesigned - early testing had squidding and tearing problems, with one parachute shredded completely.

Curiosity was heavier than the Viking landers and so had a larger parachute, backshell, and heat shield (which was made of PICA).

Perhaps I overstated the similarity. They are pretty much the same idea, though, just at different scale. And Curiosity maxes out the parachute technology, still on decades old upper atmoshere testing done in support of Viking. IIRC some versions used a ballistic entry and others used offset CG lifting entry.

The key point is that this can really be considered a single design, just at different scales, when compared to Dragon, which is a completely different approach
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Offline whitelancer64

I'd imagine an in-house SpaceX Mars rover would throw mass at the problem, and just have larger solar arrays with electric heaters
They would probably also use a Dragon as the starting point for the landing vehicle, rather than try to duplicate NASA's design, which relies on some very specialsed technology.

(Note- NASA developed a Mars EDL architecture in the 70s for Viking and has reused it every time since then. Same cone/sphere heatshield shape, same disk-gap-band supersonic parachute. Only the terminal landing sequence has been altered, to suit each mission).

Not so, the EDL hardware designs were similar, but not the same.

The MER heat shield was a different size and the backshell had a different geometry than the Viking landers, for example. Also the parachutes for the MER program were smaller and had to be extensively redesigned - early testing had squidding and tearing problems, with one parachute shredded completely.

Curiosity was heavier than the Viking landers and so had a larger parachute, backshell, and heat shield (which was made of PICA).

Perhaps I overstated the similarity. They are pretty much the same idea, though, just at different scale. And Curiosity maxes out the parachute technology, still on decades old upper atmoshere testing done in support of Viking. IIRC some versions used a ballistic entry and others used offset CG lifting entry.

The key point is that this can really be considered a single design, just at different scales, when compared to Dragon, which is a completely different approach

A similar EDL method would be a better way to put it.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Oersted

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #32 on: 05/11/2017 07:57 AM »
I'd imagine an in-house SpaceX Mars rover would throw mass at the problem, and just have larger solar arrays with electric heaters
They would probably also use a Dragon as the starting point for the landing vehicle, rather than try to duplicate NASA's design, which relies on some very specialsed technology.

"landing vehicle" you say, but mobility will be crucial to reconnoiter a possible colony location. Building a rover from scratch and then modifying Red Dragon to deploy it sounds to me like a huge job, compared to the approach I am proposing.
« Last Edit: 05/11/2017 07:57 AM by Oersted »

Online philw1776

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #33 on: 05/13/2017 07:30 PM »
I ran engineering, developed new products and put them in production and supported them.  One major problem with old designs in production is the obsolescence of electronics parts which evolve rapidly.  In telecom we contractually signed up to provide more of a given product 10 years beyond initial purchase. Commercially we forecast a lifetime build # of units and then did a final stock buy of the many parts that our vendors were dropping during this 10 year period. 
JPL's design is ancient.  Worse yet they used proven parts that were old at the time.  Again worse they used many specialized low volume parts not kept in production for anyone else.  Unless (and the probability here approaches zero) they spent $ to create a stockroom able to build N future rovers, the parts are long gone.  The original manufacturers no longer have the capability to make any more.  Semiconductors have evolved so many generations since that the tools and the tools to make the tools may be gone.  Test fixtures are gone, discarded long ago.  Solutions like this proposed reflect zero experience designing and maintaining real electronics products.

The isotope heaters produce another complex series of problems.  Many political as well as expensive.
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Offline bunker9603

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #34 on: 05/13/2017 08:31 PM »
Quote
Not too big a manufacturing hurdle to handle. The CTO of the company that provide the FH have side businesses manufacturing electric car & comsats. So if you can persuade him that building new MER size rovers have merit, than he can conjoured up some mini rovers.
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I would like to see what engineers from Tesla, Solar City, SpaceX and JPL would come up with if they designed a new rover.

Also would it be possible to use drones on Mars?
« Last Edit: 05/13/2017 08:32 PM by bunker9603 »

Online guckyfan

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Re: How many Opportunity Rovers could Falcon Heavy fly to Mars?
« Reply #35 on: 05/13/2017 09:02 PM »
I will try another argument. Assume they find a forgotten store of 20 Opportunity rovers and they are all operational. SpaceX can have them for free. Would they accept them and use them? No way, they are just too far from what SpaceX needs.

Maybe they could disassemble them and use those nuclear heat sources.

Tags: drones?