Dr. Zubrin on Musk Plans

tahanson43206 · 2020-02-22 17:09:51

For SpaceNut ... please move this to the best topic.

https://www.yahoo.com/news/elon-musk-pl … 02155.html

Article by Dr. Zubrin about Elon Musk.

(th)

SpaceNut · 2020-02-22 18:01:58

Rah, Rah not
Comparison of tonnage 40 to 100, crew count 5 tp 100 and nothing else....

Calliban · 2020-02-22 18:22:48

Very impressive. To solve the landing problem, Musk needs to find a site where the Martian winds have stripped away the regolith leaving bed rock. It would be advantageous if this were also close to a source of ice.

I think life on early Mars will be basic and extremely tough. But I begin to get the sense that I may see colonisation actually happen in my lifetime. I am 40 now, so if it happens by 2050, I have a good chance of watching it and maybe even working on the program. I get the sense that as soon as the first colony is set up, it will change everything. All of a sudden, most people and governments around the world will want a stake in the new world. The amount of resources devoted to Mars colonisation will increase geometrically once the majority of the human race realise that it is possible and has already started. An exciting time to be alive!

louis · 2020-02-22 18:32:22

Oh dear. Zubrin is not very convincing.

“In 2001, I was among those who helped convince him to make Mars his calling. His plan is based to a significant degree on my own work, which is generally known as the Mars Direct plan.”

Really? I don’t think so.

Musk’s plan bears little relation to Zubrin’s apart from propellant production on Mars.

Zubrin claims the Starship can deliver as much as 200 tons to the Mars surface! That’s news to me. I thought 100 tons was the upper limit and the likelihood is that design constrictions may pull that figure down.

Zubrin’s obviously wrong in claiming you have to set up your 10 football fields of PV array before you can land humans on Mars. That’s nonsense. Most of the PV array can be set up after humans arrive.

Zubrin claims that : “An extraterrestrial settlement is unlikely to be able to produce a profit by export of any material commodity to Earth. The transport costs are simply too great, and so the numbers in business plans based on such concepts just don’t add up. “

This is absurd. Meteorites, regolith, gold, jewellery, luxury goods (e.g. Rolex watches finished on Mars) and Mars ephemera (collectible items - basically any material artefact associated with the early pioneering effort) will all cover the cost of transportation. There would be a market even for Mars water ("purest in the solar system").

Zubrin’s article ends sadly with his pathetic attempt to get Musk to adopt a "Mini Starship" approach ie something close to Zubrin's proposal.

Last edited by louis (2020-02-22 18:33:07)

Calliban · 2020-02-22 19:14:08

louis wrote:

Oh dear. Zubrin is not very convincing.
Zubrin claims that : “An extraterrestrial settlement is unlikely to be able to produce a profit by export of any material commodity to Earth. The transport costs are simply too great, and so the numbers in business plans based on such concepts just don’t add up. “
This is absurd. Meteorites, regolith, gold, jewellery, luxury goods (e.g. Rolex watches finished on Mars) and Mars ephemera (collectible items - basically any material artefact associated with the early pioneering effort) will all cover the cost of transportation. There would be a market even for Mars water ("purest in the solar system").

Is it really so absurd? All the items you are talking about are quite niche and they would lose their novelty value quite quickly. Bulk commodities require mining. There is no reason to expect mining to be any easier on Mars than it is on Earth. And to do it, you need to ship the requisite equipment from Earth and then operate it in Antarctic temperatures under vacuum conditions. Then you need to ship the commodities back to Earth orbit and somehow get them back down through Earth atmosphere safely. It is possible, but is it really going to be cheaper than mining the material on Earth?

Last edited by Calliban (2020-02-22 19:14:38)

SpaceNut · 2020-02-22 20:11:26

https://www.nationalreview.com/2020/02/ … ed-planet/

We have run the solar panel numbers and they are not fitting into a single starship bound for mars and in fact it took multiple just to be able to produce the insitu fuels to return home....The mass for batteries took in the fin power sources but left many tons of those still in an unknown status to solve for.

https://www.tesmanian.com/blogs/tesmani … ert-zubrin

Building a smaller mini starship is the way to leverage for fuel production needs of the larger starship as it leaves behind the equipment from each of those smaller successes in order to not fill a starship full of stuff that we already have in place for its arrival.

https://www.space.com/crewed-mars-direc … -2019.html
Mars Society Founder Makes Case for 'Mars Direct' Path to the Red Planet By Elizabeth Howell November 06, 2019
The 30-year-old plan has stood the test of time, Robert Zubrin stressed.

https://www.econotimes.com/NASA-Elon-Mu … in-1575534

SpaceNut · 2020-02-22 20:42:22

louis wrote:

Hmmm, not sure I entirely misunderstood!
My point was that while in the past creative discussion about different mission architectures had been relevant (and I was an enthusiastic contributor) we are entering a different era now. If my analysis is correct, then there is only one organisation that is going to land the first humans on Mars and that is Space X... and they have already effectively made their choice about mission architecture (a series of single rockets from LEO to Mars surface and back to the Earth's surface, with refuelling in LEO and on Mars, using solar power on Mars). That makes discussion of other mission architectures redundant. If the Starship is successful, it will dominate Earth-Mars transport for the foreseeable future because it has no other short term competitors.
In that context, I think any mission statement should focus on how best to take forward human colonisation of Mars using the Space X-Starship architecture as a given. Of course that doesn't preclude someone saying "I have a better architecture than Space X that can realistically be put in place within the next 20 years" - but I very much doubt anyone can do that.
It seems to be there are huge areas to discuss, where we need to work out the best approaches: space medicine (keeping humans healthy on Mars), energy and energy storage systems, the likely pattern of settlement development and transport systems on Mars, terraformation, para-terraformation, how to organise settlement, should a state be formed on Mars and if so how should it be organised etc etc.
But alternative rocketry is likely to be pretty irrelevant I feel.
tahanson43206 wrote:
Thanks to Louis and kbd512 for your contributions to this topic.
Louis, you appear to have misunderstood what this topic is about, and I am most interested in enlisting your substantial capability to help.
The purpose of this topic is NOT to talk about a particular person's "mission" to Mars.
The purpose of this topic ** IS ** to work out a statement that would appear at the top of the main page for the forum. It would contain text that covers the collective objective (whatever that may turn out to be) AND the rules by which this little collection of human beings will try to conduct themselves in the course of the journey.
kbd512, I liked your post, because it seems (to my eye) to catch a bit of the flavor of what this topic is about.
For anyone and everyone with an interest in the future of this forum ... please go scouting for mission statements of various organizations, and post a summary in this topic, so we can collectively begin to get a sense of what might match this particular group at this point in its (by now) long history.
The mission statement needs to (somehow) encapsulate the entire range of personality types on view in the NewMars archive.
It's easy enough of me to say those words. It will be exceedingly difficult for the group to arrive at anything like a consensus one what we can all live with.
However (the ultimate point I'm trying to make) whatever we come up with will provide a good indication of what can be expected at Mars.
The chauvinism of some who participate here is on display, and that set of attitudes must be somehow blended into the attitudes of others who are more inclusive. This is pretty much the problem the American society is facing, and (I gather) is facing almost every society on Earth today.
(th)

SpaceNut · 2020-02-22 20:43:07

kbd512 wrote:

Louis,
The great thing about freedom of speech and freedom of thought is that you're completely free to continue your myopic "single-solution, no other solutions even possible" focus on what SpaceX is doing and some of the rest of us are equally free to come up with potential alternatives that would be truly sustainable now and into the foreseeable future. My thought process is that SpaceX's proposed mission architecture is the exact opposite of what would realistically be required for colonization of Mars. Launching 6 super heavy lift rockets to deliver a 100t of payload to Mars is a tacit admission that nobody presently has a good plan for colonization.
19,800t of propellant per 100t of payload delivered is an unsustainably bad energy trade, plain and simple. It's significantly worse than SLS, even though it has the benefit of being reusable if it actually works. We'll only know that after on-orbit bulk cryogen transfer is attempted for the first time. Each 100t of delivered payload is consuming the equivalent tonnage of propellant, in terms of mass, of a small aircraft carrier or amphibious ship. We don't fly too often here on Earth, even with vastly cheaper fuel bills associated with vastly lower dV / speed requirements, because it still costs too much, yet somehow we're going to send the population of a small city to another planet with exponentially higher fuel bills and life support requirements when compared to airliners. I'm guessing we won't. At best, we might end up with a mind-blowingly expensive deep space version of our Antarctic research station with perhaps 100 to 1,000 people. The idea that the average Joe will ever live there is just plain silly, seeing as how nobody who isn't sponsored by a government or corporation or is independently wealthy ever winters over in Antarctica.
SpaceX isn't going to send a 100t payload to Mars in 3 months because their rocket doesn't have the dV to do that. That means they're going out on the minimum energy free return trajectory, so a minimum of 6 months in space. At 6 months, humans do a lot better in artificial gravity than they do in microgravity. Unfortunately, Starship isn't capable of providing that. It's not a big deal for astronauts, but again, the average Joe will never fair well in that kind of environment and more proof that a colony of ordinary people is a pipe dream using chemical rockets, as if more was actually required. We're also not going to train a million astronauts when training is several million dollars per astronaut, unless we discover several trillion more dollars we're not doing anything with, like paying fuel bills or maintaining a fleet of a thousand Starships.
After Starship gets there, it basically has to land somewhere that's flat as a pancake and as hard as concrete. Anyone who's simply carried something in their arms can look up at that thing's payload bay and know that it's the worst possible design for rough field stability. Unless you can guarantee a landing on a concrete pad, it remains an unsolved problem. You'll suddenly "discover" this the first time they try to land Starship on sand. Many places on Mars the ground is basically fine sand 10+ feet deep, so no matter where it lands it may not be all that stable. It's solvable, as GW pointed out, but their design doesn't illustrate any such thinking in its design. I think a few of their engineers need to take a ride on a C-130 that's landing on beach for the point to be driven home.
So, rather than pointing out all the painfully obvious problems, at least to people who are engineers, what are my proposed solutions?
1. The most intractable problem to space colonization is not having somewhere to go or even knowing how to design a ship to go there- because we did that before CAD and CFD ever existed, it's figuring out how to obtain a reasonable payload fraction for a given propellant consumption. So, how do we do that?
A. We use an electromagnetic launch system, not to achieve orbital velocity before we leave the track, but merely to eliminate the requirement for that gargantuan booster by replacing the dV increment provided by the booster with substantially more efficient electromagnetic acceleration. After that booster disappears, roughly 2/3rds of propellant mass, vehicle mass, and associated development / maintenance costs are offloaded to a ground-based system that doesn't have any real mass or power constraints.
Even if we just stick with conventional LOX/LH2 or LOX/LCH4 or LOX/RP-1 propellant from there, we've arrived at a fuel burn not significantly worse than a passenger airliner flying half way across the world. Lo and behold, at least a billion passengers can afford air travel each year because the cost associated with that kind of fuel burn is entirely within the realm of economic feasibility for at least 1/7th of the world's population, a number growing by the day as we use more efficient energy technology to beat the living crap out of systemic poverty associated with energy-poor pre-industrialized societies. Since most of us living in industrialized societies can afford that once per year, that considerably expands the pool of economically qualified space colonization applicants. Recall that we do have to actually procure our Mars colonists and there may not be an infinite supply of wealthy and highly educated applicants who want to sell everything they own to move to Mars.
B. Assuming that in the next couple of decades or so that we really want to "go for the gold" when it comes to ultimate fuel efficiency, then we can also employ high-powered microwave transmitters to act upon heat exchangers to provide nuclear thermal rocket specific impulse levels for the final push to orbital velocity. At this point, the fuel burn associated with attaining orbital velocity is no worse than running current bleeding edge technology high-bypass turbofan engines for several hours. As a bonus, no onboard explosive mixture of oxidizer and fuel is required. The fuel is pure H2.
After we get there at the cost of an international flight ticket, we're half-way to anywhere else we want to go.
2. Once we're in orbit, we no longer have to use horribly inefficient chemical rockets to go other places. High-powered electric propulsion is the way to go. Since there's full Sun 24/7/365, if we have artificial gravity and electromagnetic shielding, there's really no great rush to land somewhere else. A leisurely orbital transfer followed by another leisurely orbital transfer at the destination planet is far preferable to a screaming interplanetary reentry with the thinnest of margins between a successful landing and becoming a man-made impact crater.
3. We design purpose-built interplanetary transports and purpose-built landers. Starship does look like the beginning of a decent reusable purpose-built lander, but it can either be good at landing on things in rough terrain or it can be a good upper stage for an orbital class super heavy lift rocket, but not both. It certainly won't be everything else that Elon Musk says it will be.
A. A purpose-built interplanetary transport needs artificial gravity, electromagnetic space radiation shielding, space debris shielding, and electric propulsion. It need not ever reenter a planetary atmosphere and it's much better from a design optimization standpoint if it doesn't.
B. A purpose-built lander needs to be designed with a low-CG, low-BC, and enough mass to be truly reusable. It needs to cope with significant periods of disuse, have reliable engines and propellant handling systems with minimal complexity, and be easy to maintain in the field. This is pretty much the exact opposite of an optimal upper stage designed for a rocket.
C. It must be understood that cost ultimately wins when it comes to the shipping business, which at least appears to be the business that we really want to be engaged in. Our routes are a little longer than your average milk run, but the basic concept remains the same. An interplanetary cargo transport system that costs many thousands of dollars per pound is not a feasible proposition for any other long-term user apart from the government of a very wealthy nation. That's the current status quo, so nothing much will change by introducing another heavy lift rocket that has to refuel half a dozen times to go anywhere else. The bulk of the cost therefore appears to be associated with merely achieving orbital velocity. That's the "real engineering" problem that needs to be solved. Trying to create a "single solution" to every problem associated with space activities from satellite launch to transport to reentry is precisely the same sort of issue that made the Space Shuttle unaffordable to operate. The design requirements for all of those activities is so wildly different that there can't and won't be any practical / economically feasible solution for all of them rolled into a single design.
As far as relevancy is concerned, I have a feeling that the first company that builds an orbital class transport that can transport a ton of whatever at present air freight rates is likely to make SpaceX's entire line of rockets irrelevant. Nobody will pay more money to ship something to orbit when they can simply re-schedule their cargo for the next outbound flight. A vertical launch rocket is unlikely to ever achieve that kind of launch rate and nothing of the sort has been demonstrated to date by SpaceX or anyone else because they persist with this outmoded "main event" kind of space launch service that requires months of careful planning versus two pilots and an air traffic controller. All passenger airline services can and often do change their flight plans by the hour without so much as a hiccup in the overall air transport operation. Eliminating the booster and simply flying off of a runway or electromagnetic launch track (a land-based catapult system) makes it possible to depart every couple of minutes.
So, no, nothing I've seen thus far makes SpaceX's plan look any more realistic than any other plan. They're building another heavy lift rocket, which is kinda funny since they already have one. All of the technologies they say they need to get working for their Mars colonization plan to work, or at least the transportation phases of it, should've been tested using their smaller and less expensive rocket that, at least in theory, requires no additional development just to fly and test the concepts required to make Starship work. If they couldn't make reusability work as well as they need it to with a smaller and cheaper rocket, then I fail to see how the economics will improve when they "super size it".

kbd512 · 2020-02-22 23:28:01

Louis,

Maybe we could have robots that are capable enough to setup the materials in the rough locations required and then humans could arrive and make all the electrical connections or final adjustments using hand tools. If that's what you meant by automation, then yeah, I could see that happening. That said, we're going to have to plan on EVA's. If the plan is to just sit back and watch robots work, then we can do that from the comfort of Earth where no lives are at risk.

Given how long it takes to set up a solar farm on Earth with unlimited manpower and equipment, we're going to need a well-rehearsed plan, lots of practice with setup of real solar arrays wearing real pressurized space suits, and maybe some kind of helper robots or machines that follow the crew around feeding rolls of PV or wiring to them so they can simply make electrical connections as fast as they can.

Calliban · 2020-02-23 05:27:42

Kbd, it would be interesting to investigate an electric propulsion vehicle that could use unprocessed regolith as propellant. If the vehicle has exhaust velocity of 10km/s or more, then it can refuel at Phobos or Deimos for the trip back to Earth and still have enough propellant to make the trip back to Mars again. No propellant would need to be shipped from Earth aside from that needed for the first flight.

A mass driver could function with a solid propellant, but it would appear to be a large, heavy and complex device. An Arcjet is another option. Dust could be converted into ions within an arc jet if it is present within a carrier gas. Small amounts of argon could be harvested from the Martian atmosphere. Alternatively, maybe a VASIMR type device could be used.

Last edited by Calliban (2020-02-23 06:17:59)

louis · 2020-02-23 07:41:46

Well it was Zubrin who put in the "any".

The global luxury watch market is worth nearly 7 billion dollars annually. Are you telling me the "boys who like toys" aren't going to be attracted to a Rolex incorporating say a Mars diamond or other gem in its face. Wouldn't that be a talking point? - and just knowing the watches have come all the way from Mars would add huge cachet.

The Rolex Submariner watch can cost maybe $40,000 and weighs in at 155 grams. So we could be talking about $260,000 per Kg value at a minimum. You could probably charge a lot more for a special edition Mars Astronaut watch. Let's say you can realise $400,000 per kg or $400 million per ton or $40 billion per 100 tons of cargo. Obviously you won't be able to find enough people to buy 100 tons of luxury watches, but it makes the point that the mass/value relation could create huge value.

You could import the parts to Mars and assemble the watches there using nearly all automated machinery.

What other luxury items might fit the bill? I would suggest jewellry and possible v. light clothing e.g. chiffon scarves. Sadly Mars is more associated with the male gender, so will be less appealing to women. Mars art works will also have intrinsic value back on Mars I would suggest, especially if you incorporate local materials.

You claim: "There is no reason to expect mining to be any easier on Mars than it is on Earth." I disagree. Unless there has been a previous civilisation on Mars that mined gold and other precious metals, we should find exposed concentrations at the surface on Mars, needing only to be drilled out. When it comes to processing the ore, you don't have to pay for land use, for licences, for taxes. Also, you don't have to worry about environmental pollution, in so far as it has no direct impact on the habs area.

Of course, if there has been life on Mars, or still is, that is another "gold mine" since fossils and living creatures will be of incalculable value.

Calliban wrote:

louis wrote:
Oh dear. Zubrin is not very convincing.
Zubrin claims that : “An extraterrestrial settlement is unlikely to be able to produce a profit by export of any material commodity to Earth. The transport costs are simply too great, and so the numbers in business plans based on such concepts just don’t add up. “
This is absurd. Meteorites, regolith, gold, jewellery, luxury goods (e.g. Rolex watches finished on Mars) and Mars ephemera (collectible items - basically any material artefact associated with the early pioneering effort) will all cover the cost of transportation. There would be a market even for Mars water ("purest in the solar system").
Is it really so absurd? All the items you are talking about are quite niche and they would lose their novelty value quite quickly. Bulk commodities require mining. There is no reason to expect mining to be any easier on Mars than it is on Earth. And to do it, you need to ship the requisite equipment from Earth and then operate it in Antarctic temperatures under vacuum conditions. Then you need to ship the commodities back to Earth orbit and somehow get them back down through Earth atmosphere safely. It is possible, but is it really going to be cheaper than mining the material on Earth?

louis · 2020-02-23 07:47:32

The reason solar farms on Earth have to be so robust is the weather on Earth: hurricanes, tornadoes, rain storms, hail storms etc etc The weather on Mars is benign with the wind force being something like 1/20th that on Earth, so even a 60 MPH wind (top recorded I think) has puny effects.

My favoured solution is to have wires suspended between poles (probably just two parallel wires will suffice) and then hang the very lightweight PV film (off a roll) on to the wires (probably using hooks). How you secure the poles will need some attention.

kbd512 wrote:

Louis,
Maybe we could have robots that are capable enough to setup the materials in the rough locations required and then humans could arrive and make all the electrical connections or final adjustments using hand tools. If that's what you meant by automation, then yeah, I could see that happening. That said, we're going to have to plan on EVA's. If the plan is to just sit back and watch robots work, then we can do that from the comfort of Earth where no lives are at risk.
Given how long it takes to set up a solar farm on Earth with unlimited manpower and equipment, we're going to need a well-rehearsed plan, lots of practice with setup of real solar arrays wearing real pressurized space suits, and maybe some kind of helper robots or machines that follow the crew around feeding rolls of PV or wiring to them so they can simply make electrical connections as fast as they can.

SpaceNut · 2020-02-23 10:04:18

louis posts 11 12 replies

Mars branding of items made there is a means but we can do that now with nothing being brought from mars at all as fakes sell just as good as the real stuff would.

A rock is a Rock either here or mars as its only gravity that will be different for moving it as they are the same materials. Mining on mars will be more dangerous as we have no air to breath, that fragments could puncture the space suit, and that automated equipment will be slower and breakdown requiring more eva's to repair increasing risk.

Tension wires (steel cable) break when the mass is blown by wind and that will break the panels wires as well. That said louis calculate the size wire (steel cable) that you will bring for mass for tension and wiring of the panels from earth its total lengths to support all of the panels plus all of the poles needed to anchor it in place.
Rollout thin film plastic panels (12% - 15% eff.) are less efficient and require twice if even more panels than fixed glass (25% - 35% eff.) which will survive the mars weather where as the plastic type will not.

elderflower · 2020-02-23 14:32:46

It won't be steel cable. It will be Dyneema or equivalent. Very high MW polyethylene. As strong as steel and with similar stretchability (ie not a lot), but about 15% of the weight.

louis · 2020-02-23 15:44:10

Yes there's a trade off in efficiency but I would definitely go for ultra-lightweight flexible PV off a roll. The mass difference is v. significant compared with traditional PV.

As stated, the wind force on Mars is insignificant. IIRC, it's something like 1/20th that of the wind force on Earth for any given speed and I think 60MPH is in any case the top wind speed ever recorded on Mars. The wires and poles will not have to be very robust. Obviously whatever material they are made of will have to be Mars-proof, in particular in relation to the temperature swings. The poles might have have containers at their base which can be filled with regolith to weigh them down.

This is something that trained engineers need to look at. It might make more sense to hang the PV roll between two sturdier structures. The PV roll doesn't need to be under high tension. That might be a better approach. Whichever approach involves the least mass would be favoured as long as it is easy to assemble.

SpaceNut wrote:

louis posts 11 12 replies
Mars branding of items made there is a means but we can do that now with nothing being brought from mars at all as fakes sell just as good as the real stuff would.
A rock is a Rock either here or mars as its only gravity that will be different for moving it as they are the same materials. Mining on mars will be more dangerous as we have no air to breath, that fragments could puncture the space suit, and that automated equipment will be slower and breakdown requiring more eva's to repair increasing risk.
Tension wires (steel cable) break when the mass is blown by wind and that will break the panels wires as well. That said louis calculate the size wire (steel cable) that you will bring for mass for tension and wiring of the panels from earth its total lengths to support all of the panels plus all of the poles needed to anchor it in place.
Rollout thin film plastic panels (12% - 15% eff.) are less efficient and require twice if even more panels than fixed glass (25% - 35% eff.) which will survive the mars weather where as the plastic type will not.

SpaceNut · 2020-02-23 15:55:18

The link for the roll of panel materials so that we can do just that
Which can tell us how tight of a roll, its width plus depth of the rolled panel, power levels, mass ect...
Statement of starship energy power levels for all insitu operations required to make the fuel, fuel rate for day count to make the fuel...

louis · 2020-02-23 17:38:22

Obviously this is designed for Earth but something like Renovagen's "Rapid Roll" PV system could be developed for Mars.

http://www.renovagen.com/technology/#rapidrollsolarpv

This one is deployed flat on the ground by a vehicle.

That's one approach that might work on Mars. Clearly on Mars a robot rover or human passenger rover could unpack the Rapid Roll on to the surface in a matter of minutes. Obviously dust is more of an issue on Mars. This is something that would have to be assessed. If it was felt a ground system was too vulnerable to dust we could have a second process where the roll was lifted of the ground at an appropriate angle and attached to supports at regular intervals.

SpaceNut wrote:

The link for the roll of panel materials so that we can do just that
Which can tell us how tight of a roll, its width plus depth of the rolled panel, power levels, mass ect...
Statement of starship energy power levels for all insitu operations required to make the fuel, fuel rate for day count to make the fuel...

Calliban · 2020-02-23 17:56:40

Ultra-lightweight thin film PV presumably does not include any cover glass for abrasion and UV resistance. Under those conditions, what would be the effective lifetime of panels on Mars? Would they last a year?

It is also noteworthy that very thin semiconductor layers will have very low breakdown voltage. That is a problem, as very low voltage would lead to high resistance losses in long rolls of PV panels. The panels would need inverters and transformers at regular intervals. That adds extra weight to the PV system.

Realistic space PV systems achieve about 1kg/m2. On Mars, that would mean realistic power density of about 10W/kg. How much power does the Starship need for its return propellant provisions? How much for other things?

SpaceNut · 2020-02-23 18:51:27

posted magical panels here in louis solar topic

louis · 2020-02-23 19:10:35

Of course they would last a year. We have experience of PV arrays in dusty deserts on Earth, so we know how they react. But bear in mind the wind force on Mars is about 1/20th of that on Earth, so dust particles are not being slammed against the surface with the same force as on Earth. In a dusty environment there will clearly be some abrasive degradation in the PV systems, but bear in mind we've had Rovers on Mars operating in those conditions for 12 years or more and they still functioned very well.

Also, remember that - as with the Apollo mission - for Mission One to Mars, cost is not a major consideration. If you have to spend $1 billion on your energy system, that's not a big issue in terms of the overall budget. So if that's what it costs to get a lightweight resistant surface on the PV array, so be it. Space X can afford $1 billion for the energy system.

How much power do we need to cover propellant production? I think the conservative (upper limit) figure is 1MW constant...probably translates into something like 8 MW solar capacity.

Calliban wrote:

Ultra-lightweight thin film PV presumably does not include any cover glass for abrasion and UV resistance. Under those conditions, what would be the effective lifetime of panels on Mars? Would they last a year?
It is also noteworthy that very thin semiconductor layers will have very low breakdown voltage. That is a problem, as very low voltage would lead to high resistance losses in long rolls of PV panels. The panels would need inverters and transformers at regular intervals. That adds extra weight to the PV system.
Realistic space PV systems achieve about 1kg/m2. On Mars, that would mean realistic power density of about 10W/kg. How much power does the Starship need for its return propellant provisions? How much for other things?

SpaceNut · 2020-02-23 19:25:32

SpaceNut wrote:

posted magical panels here in louis solar topic

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Dr. Zubrin on Musk Plans

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#20 2020-02-23 19:10:35

Re: Dr. Zubrin on Musk Plans

#21 2020-02-23 19:25:32

Re: Dr. Zubrin on Musk Plans

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