This thread started as a conversation about a Lockheed-Martin proposal for a manned trip to Mars that does not land. Looking back at post #1 with the picture in it, I see a rather large vehicle, that if reconfigured, could be spun for artificial gravity. I do question why it needs two Orion CSM's. It looks to me like somebody just threw them in for symmetry and balance. That's no way to design a spacecraft.
I really do have to question why anyone would propose a manned mission to Mars without landing, as difficult as it is to send people all that way and return them home, at this time in history. To me, that notion seems as ridiculous as Columbus sailing to the new world, looking over the rail at it, and then sailing back to Spain without ever setting foot on a single beach.
I don't think I'd view the L-M vehicle proposal as anything but a device to spark a conversation.
GW
One possibility is they need the full crew complement of two Orion capsule to fully staff this mobile Mars station. I seem to recall that each Orion can carry 4 people to interplanetary space, so maybe the crew complement is 8 and they need two Orion capsules to return them all to Earth/ You think that is the reason?
]]>I really do have to question why anyone would propose a manned mission to Mars without landing, as difficult as it is to send people all that way and return them home, at this time in history. To me, that notion seems as ridiculous as Columbus sailing to the new world, looking over the rail at it, and then sailing back to Spain without ever setting foot on a single beach.
I don't think I'd view the L-M vehicle proposal as anything but a device to spark a conversation.
GW
]]>As for Mars, a single stage to orbit vehicle would be harder to build, but the advantage here is refueling can be done on Mars instead of in space, the need for a Mars orbiting space station is less obvious. A Venus orbiting space station would be the easiest place to send humans in the Venus system, it would be harder to send humans down into the atmosphere and bring them up again.
]]>I took advantage of imperfect life support technology by reducing hab mass during the mission as some waste is jettisoned. That reduced the tonnages significantly.
Send the unmanned portions by SEP slowboat saved an enormous amount of launched mass to be assembled in orbit. I sent 4 such packages, one the Earth return propellant, the other three were large reusable landers and some propellant for repeat trips with them. It is but a size scale-up of the solar power and electric thruster stuff we are already doing. Nothing new to develop, just re-size/re-shape/prove-in-test.
The habitat / orbit transport vehicle has nothing "new" in it, just more re-shape/re-size/prove-in-test work. That portion is dominated by launch costs, which I assumed to be today's $6M/ton, without reducing them for Falcon-Heavy's lower unit price. I use an LH2-LOX stage to depart Earth orbit, all the rest is NTO-hydrazine blend.
The lander is real vehicle development and prove-out work, so hardware costs dominate that portion, even though I send 3 of these, and have to launch their large masses, and assemble them in orbit. There is no new technology in them to develop, though. It's just the same storable propellant, a heat shield robust enough to fly through Mars orbit entry multiple times, the same supersonic retropropulsion that Spacex and Blue Origin are currently demonstrating in flight, and a willingness to scale up what we have done before to larger sizes.
Think 6 people to Mars, time spent 3 at a time on the surface in alternating crews, at up to 8 different sites, for up to 30 days at each site, with an option to install some sort of automated permanent facility at the "best" of those sites. Think spin gravity at 1 full gee or Mars gravity nearly the entire mission, just weightless during burn maneuvers. Think recovering the manned transport in Earth orbit for refit and re-use for other missions. Think crew return capsule capable of a free-return "bailout", if disaster happens, just a normal orbit entry if things go well.
I took my shot at costs, and got a number just under $50 billion. Timeline is paced by the intense test prove-out of the lander. If it proceeds like the Apollo LM did (just bigger), think 6-8 years.
Think men on Mars by about 2025.
Now compare that to the 90 day report and design reference mission stuff, and that half-a-trillion dollar price tag, to put 2-4 men on Mars closer to 2040, and get nothing but the Earth return capsule back. And nobody yet agrees on how to land all that stuff on Mars.
GW
]]>I like your example even better. I guess I should have said "best widely known", not best, for my two.
GW
]]>The model of half a millennium ago was a government-private partnership. The two best examples were the Dutch and British East India companies.
I have raised an historical example before. After Columbus came back with news of the "New World", an English explorer named John Cabot set out. In 1494 he hired two Icelandic guides, sailed a route across the north Atlantic. He discovered Newfoundland. He found a bay that formed a natural harbour, discovered on 24 June 1494 "feast day of Saint John the Baptist", so named the harbour Saint John's Harbour. He also discovered the richest fishery in the world: Grand Banks. He was a government funded explorer, documented all this in detail, that knowledge was made public as soon as he got back. The summer of 1495, English fishermen set out to fish the Grand Banks. They set up a camp on the beach of Saint John's Harbour. Government paid for the explorer, and at that time navigation was a military technology that was recently developed by the navy to allow combat ships to operate in deep ocean. Large multi-sail ships were also military technology. So fishermen (commercial business) used military technology to cross an ocean to reach newly discovered resources, used detailed data from their government funded exploration agency, but commercial business paid their own expense to utilize this resource. They sailed their own ships to the Grand Banks and set up a fishing camp to process the fish for storage. The first permanent European house was built in the summer of 1496 for a caretaker to over-winter at Saint John's, stayed the winter of 1496-1497. That fishing camp was not built by any government program, and didn't receive any government funding, it was strictly private enterprise. That fishing camp grew to become the city of Saint John's, today the capital of the Canadian province of Newfoundland.
In fact, the first street ever built in the Americas was Waterfront Street, built by town of Saint John's at a time before any government had any control. Because the street was built by businessmen, we don't know exactly when it was built, who built it, or how much it cost. All we know is one visitor wrote a letter describing the town, the street was not there. Another visitor wrote a letter describing the street. So the street must have been built between the dates of those two letters. This shows private enterprise is extremely good at building profitable business, but really sucks at documentation. Roanoke Colony, Cuttyhunk Island, and Popham Colony were government funded colonies, abject failures. Jamestown was another government funded colony, initially a failure, but government threw more money at it and re-colonized the same site. Meanwhile the colony established by private enterprise (Saint John's) merrily continued and earned gobs of profit. The economy of England had lots of cod fish from that colony. Actually, there were fishermen from England, France, Spain, Normandy, and Basque, as well as Basque whalers.
]]>GW Johnson wrote:The sulfuric acid would destroy just about all known materials that we have, on time scales from hours to a couple of weeks, even up high where it is not hot. On the surface, it is so hostile that equipment lifetimes are minutes to hours, almost no matter what you build. There is nothing available from which to fashion solid state electronics which could survive above 95 C.
This may be true when using silicon-based semi-conductors, but diamond-based semi-conductors can survive far higher operating temperatures and diamond-based semi-conductors are by no means science fiction technology.
The sulfuric acid is a real problem, but I think the extreme surface pressures are a far greater problem than heat or corrosive substances in the atmosphere. Jet engines manage to survive more extreme operating environments than Venus for many thousands of hours, although not without maintenance.
A conventional jet engine would work on Venus, you just need to bring the oxygen. The oxygen burns the jet fuel, to heat the carbon-dioxide that comes through the jet intake, this will still be more efficient than a pure rocket engine, as the Venus atmosphere serves as reaction mass to push against.
]]>What other than the mass of push stages and comsumables would there be different for a venus versus a mars mission that only orbits or does a flyby. I know that this is not a mission that can be done multiple times and that we would need to design it for the least cost possible....
Radiational shielding mass...
Is there anything else?
I think Solar flares are easy to shield against, they are charged particles after all, its the cosmic rays that are the problem, and those are no more intense around Venus than they are around Mars. I think the benefit of a Venus mission is it would last 2/3rds as long as a Mars Mission, thereby astronauts would accumulate only 2/3rds as much unavoidable radiation as those on a Mars mission would. A Venus Mission would require only 2/3rds as much food for the same number of people, this could mean that we might send nine people to Venus with the same supply of food that we'd need for six people going to Mars. This would mean operating more drones simultaneously. Now if we want to collect rocks from the surface of Venus, using forseeable technology. we would have to collect those rocks fast, put them in a basket, and then send another drone down to the surface to quickly retrieve that basket of rocks, ascend to a more hospitable layer of atmosphere, and transfer that basket of rocks to an launcher that we drop down from orbit, that can deliver those rocks the rest of the way to orbit, to be picked up by the orbiting spacecraft. Problem is, the crew might want something to do for the rest of their 412 day stay. Maybe we can make the Venus stay shorter with a Mars flyby. You have to remember than Venus over takes Mars in its orbit much more quickly than it does Earth. So we can have an outbound trip to Mars from Venus, and then have the Martian gravity bend the path towards Earth, or we could use a Mars flyby to bend the path towards Venus. One might try a Mercury flyby as well, though I understand it is harder to get to Mercury than to Jupiter.
]]>The model of half a millennium ago was a government-private partnership. The two best examples were the Dutch and British East India companies. The comparisons are not perfect, but basically the "exploration" (go and find out what is there and exactly where it is) was mostly a government-funded thing. The private concerns were the ones who planted the colonies, mostly by private funding, based on what the government explorations found.
There was a sort of transition period between these phases, where one learns to live off the land using the identified resources. That transition was improperly managed in a lot of cases, which is why as many colonies ailed as happened, and why so many others survived only "by the skin of their teeth" (Jamestown, for example).
Nothing I have seen, not in all these decades, takes that model into account. And yet it was usually successful, if done right. We've been hung up on government programs that morph into giant-corporate welfare for about 60 years now, as far as space is concerned. 70+ years if you include defense spending.
GW
Government-Private ownership is what sparked the American Revolution. The Tea tax was a marketing mechanism to guarantee a monopoly of the in favor companies at the expense of other companies. What we need are rules that allow companies to compete and exploit space with no favoritism shown towards certain companies at the expense of others. We want the companies with the best ideas and procedures to be the most successful in capturing profits, not the ones that have cozy deals with the government. The government should be a referee, not a player. As for defense spending, if we do not defend our colonies, we will lose them, as the Dutch had discovered when they lost New Amsterdam to the British.
]]>The sulfuric acid would destroy just about all known materials that we have, on time scales from hours to a couple of weeks, even up high where it is not hot. On the surface, it is so hostile that equipment lifetimes are minutes to hours, almost no matter what you build. There is nothing available from which to fashion solid state electronics which could survive above 95 C.
This may be true when using silicon-based semi-conductors, but diamond-based semi-conductors can survive far higher operating temperatures and diamond-based semi-conductors are by no means science fiction technology.
The sulfuric acid is a real problem, but I think the extreme surface pressures are a far greater problem than heat or corrosive substances in the atmosphere. Jet engines manage to survive more extreme operating environments than Venus for many thousands of hours, although not without maintenance.
]]>Radiational shielding mass...
Is there anything else?
]]>There was a sort of transition period between these phases, where one learns to live off the land using the identified resources. That transition was improperly managed in a lot of cases, which is why as many colonies ailed as happened, and why so many others survived only "by the skin of their teeth" (Jamestown, for example).
Nothing I have seen, not in all these decades, takes that model into account. And yet it was usually successful, if done right. We've been hung up on government programs that morph into giant-corporate welfare for about 60 years now, as far as space is concerned. 70+ years if you include defense spending.
GW
]]>Hang your Mars arrival tanks alongside this baton-shaped cluster. Put your Earth departure tanks and their engines at one end, and your other engines on the other end. You can use LH2-LOX for Earth departure, but I recommend years-capable storables for all the rest (likely MMH-NTO).
After departure burn and stage-off of departure tanks, you spin up the balanced baton, for artificial gravity until you reach Mars. Rendezvous with your Earth return propellant and dock it up the same way: Earth arrival tanks fatten the baton, Mars departure tanks on one end. Artificial gravity makes possible real cooking with real food, easier water/wastewater life support designs, and (get this) real laundry!!!!! And real bathing!!!
You also send ahead by nuke or solar electric propulsion your landers and your other equipment, and you send ahead your Earth return propellants that same way. Its all just rendezvous in LMO, just like Apollo did at the moon, just more stuff. The more landers and lander propellant you send ahead, the more landings at more different sites you can make while you are there. It's only how much you think you can afford. Talk about bang for the buck!
Two modified B-330's at 25, not 20, tons each, plus a ton of engines and 15 tons of center module, plus 50 tons of supplies and a crew of 6 totals about 125 tons deadhead, to which I attach all the propulsion items. It's also about 700 cubic meters of interior volume available. That's over 100 cubic meters for each of 6 crew, which is better than even Skylab, and certainly way better than anything since.
I'm showing 1050 tons at departure from LEO, including the departure and arrival propulsion, but not including the sent-ahead stuff, among which is 1614 tons of return propellant tankage. I haven't done the landers yet. I'm showing 1739 tons at departure from LMO, even including the full 50 tons of supplies, which is far too conservative. The craft decelerates into LEO for refit and reuse, many times.
I know Bigelow signed a deal to start launching B330's on Atlas-5's by about 2020. If Musk is as smart as we all think, Spacex should be getting with Bigelow to start on this Mars ship. Every bit of this is launchable by Falcon-Heavy. But even at Atlas-5 prices, it's well under $100B to launch this thing. And launch costs are the biggest estimates I have right now.
The hardest thing about the whole deal is developing a lander. Putting ordinary tankage into the shapes you need is no big development program. Nor would be modifying the B330 with fold-out internal decks and enough strength to take the spin loads.
There's no need for the 90-Day Report concepts, nor its half-a-trillion dollar price tag. What you're seeing is giant corporate welfare. Give this mission to ULA, and that's all you will EVER see.
GW
]]>