More space news!

[Old Man]

Re: More space news!

 

Then most space scientes you are aquainted with have a very narrow view of humanities future

 

No, I think they'd love to see a manned space program. They're just realistic given the political climate and the current NASA budget, or lack thereof. If we could pay for the manned program out of the defense budget* I think you'd find few scientists who would oppose it.

 

 

* While somehow keeping the military out of it, of course.

[Tom Carman]

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No Buck Rogers, no bucks.

[Christopher]

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Lovejoy, the sun gazing comet, holds a lot more mysteries than thought at first:

[DusterBoy]

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Lovejoy, the sun gazing comet, holds a lot more mysteries than thought at first:

 

That was no comet, that was Rama, refueling.

[SteveZilla]

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Or the Destiny...

[Gnaskar]

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NASA doesn't have unlimited money, which is sad. So it has to make tough choices about which experiments it is going to do. The argument is that the ISS has been insanely expensive because it's done a very good job demonstrating just how much harder it is to live and work in orbit than the handwave school thinks it really must be.

 

And that's the thing. NASA and its partner agencies keep saying that this is hard stuff to do, and we need to spend lots of money to get these things right, and the experiments and trials can't come together instantly, so it will take time, too. And the critics keep saying, in effect, "Neener neener no noes." Maybe there's a grand conspiracy to stop space exploration by ...spending lots of money on it. And maybe, just conceivably maybe, NASA actually has a point.

 

The ISS has to date cost tax payers about 150 billion. Mir, built using many of the same technologies, but using a heavy disposable booster rather than a space shuttle, cost 4.7 billion. The cost of a Saturn V launch (in modern currency), is 1.1 billion dollars. The cost of a shuttle launch is 1.5 billion. The Saturn V has seven times the payload capacity. It took 27 shuttle missions to put ISS together; about a third of the final cost of the station. And that's before we start with the fact that orbital assembly is extremely difficult and thus expensive, so the rational thing to do is to do it as little as possible. The ISS is made of 16 pressurized modules, each weighing less than 20 tons (because that's all the shuttle could carry). Had the mission been designed for a Saturn V launch, it would have taken two launches to provide the equivalent living space (one orbital mating of pressurized modules*) and a third to bring up the solar panels and other utility modules. Factor in maybe five to ten shuttle launches for EVAs related to initial assembly (unless you really want to be efficient, and use a pair of Soyuz's for the same task, at a tenth of the cost). Even if we assume no reduction of cost for reducing the number of connections from 15 to 1 (unlikely to the extreme) we've still saved 30 billion dollars (not counting what could have been saved by not using the shuttle for resupply missions [lets launch 120 tons into orbit to move 5 tons of cargo to our destination]) .

 

* Typical counter argument one: They wanted to practice orbital mating. But if that was the objective, why not then launch two 10 ton modules (where half of the weight is fuel) and repeatedly put them together and take them apart, rather than making what is largely a zero gee lab hugely more complex, and far less stable?

 

The problem with NASA is seen in the number of ex-NASA employees that have stories of good ideas being ignored because the efficient solution doesn't provide jobs to the people who voted for senators A through X, or contracts for the corporations that paid for their elections. Robert C. Truax (Sea Dragon, and the lighter variants), Robert Zubrin (Mars Direct), and Michael D. Griffin (who made the above arguments while serving as the Administrator of NASA).

 

I know it is expensive. 100 billion is a massive amount of money. It's just a lot less than 150 billion.

[Lawnmower Boy]

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The ISS has to date cost tax payers about 150 billion. Mir' date=' built using many of the same technologies, but using a heavy disposable booster rather than a space shuttle, cost 4.7 billion. The cost of a Saturn V launch (in modern currency), is 1.1 billion dollars. The cost of a shuttle launch is 1.5 billion. The Saturn V has seven times the payload capacity. It took 27 shuttle missions to put ISS together; about a third of the final cost of the station. And that's before we start with the fact that orbital assembly is extremely difficult and thus expensive, so the rational thing to do is to do it as little as possible. The ISS is made of 16 pressurized modules, each weighing less than 20 tons (because that's all the shuttle could carry). Had the mission been designed for a Saturn V launch, it would have taken two launches to provide the equivalent living space (one orbital mating of pressurized modules*) and a third to bring up the solar panels and other utility modules. Factor in maybe five to ten shuttle launches for EVAs related to initial assembly (unless you really want to be efficient, and use a pair of Soyuz's for the same task, at a tenth of the cost). Even if we assume no reduction of cost for reducing the number of connections from 15 to 1 (unlikely to the extreme) we've still saved 30 billion dollars (not counting what could have been saved by not using the shuttle for resupply missions [lets launch 120 tons into orbit to move 5 tons of cargo to our destination']) .

 

* Typical counter argument one: They wanted to practice orbital mating. But if that was the objective, why not then launch two 10 ton modules (where half of the weight is fuel) and repeatedly put them together and take them apart, rather than making what is largely a zero gee lab hugely more complex, and far less stable?

 

The problem with NASA is seen in the number of ex-NASA employees that have stories of good ideas being ignored because the efficient solution doesn't provide jobs to the people who voted for senators A through X, or contracts for the corporations that paid for their elections. Robert C. Truax (Sea Dragon, and the lighter variants), Robert Zubrin (Mars Direct), and Michael D. Griffin (who made the above arguments while serving as the Administrator of NASA).

 

I know it is expensive. 100 billion is a massive amount of money. It's just a lot less than 150 billion.

 

So the sum of the argument is that if NASA had extended the Saturn V, the most expensive launch system per shot of all time, and built the space shuttle programme that, whatever its flaws, reduced cost-per-mission to the point where orbital assembly was actually possible, and if you could actually pack an entire space station into three Saturn V payloads in the first place (problematic because you're ignoring the problem that you're launching volumes as well as weights) then NASA could have shaved $50 billion off the $150 billion cost of the space station. The fact that they didn't do this is then proof that it isn't really serious about space, but rather wanted to bankrupt the Soviet Union and provide more space industry work for congressional constituents? Which, by this theory, it is done by running fewer procurement contracts and supporting the Russian space programme?

 

Have I got that right?

 

 

Look, snark aside, I don't think that anyone is arguing that the human community couldn't have made more rapid progress in space by spending more resources on it. I think the sense is just that we're talking an asymptotic curve here --a lot more resources for a little more progress. That's the story of the Saturn V in a nutshell --crazy big, crazy dangerous, but worth it to get to the Moon in 1969.

 

Okay, we've done that. Fantasies aside, we found out that we couldn't stay on the Moon. Staying meant getting to the lunar poles (look, me repeat myself!) or taking lots of luggage. Blah blah orbital assembly pattycakes.

 

That's why, again, patience is the watchword. Build the ISS. Get used to working and living in space. One step, two steps, then run. We don't have unlimited resources, and, with patience and time, the fruits will fall into our laps --at least relative to the effort involved in running multiple simultaneous heavy lift programmes and throwing half-cocked expeditions all over near space. Maybe, heck, surely, we've taken suboptimal decisions along the way. Would we do the Space Shuttle over? Probably not. But at the time that the shuttle programme was launched, all the space enthusiasts thought that it was going to work, in just the same way that we'd be manufacturing incredibly valuable, awesome stuff on the ISS by now. The fact that we thought these things before we actually had experience of how it works in practice goes to show just how important incremental learning-by-doing is. That's why technological development is incremental, and takes time.

[Christopher]

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The ISS has to date cost tax payers about 150 billion.

For wich country is this figure? USA? Europe? Russia? All of them or some of them?

It's called "International Space Station" for a reason and a large part is that it is not a all American or all Russian Work (like SkyLab or MIR).

 

Also keep in mind that your costs are 100 Billion over a short time. They didn't have 100 Billion in that short time, so they spend 150 Billion over a longer time.

It's the same concept as with a one week or one month ticket for the bus: If you can actually make your 7/30 rides in that week/month, it's a bargain. If not, looks like you have to spend the money on 7 or 30 single ride tickets...

[Gnaskar]

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So the sum of the argument is that if NASA had extended the Saturn V' date=' the most expensive launch system per shot of all time,[/quote']

Second most. The Shuttle was worse.

 

built the space shuttle programme that' date=' whatever its flaws, reduced cost-per-mission to the point where orbital assembly was actually possible,[/quote']

The Shuttle costs 50% MORE per launch than the Saturn V! The already existing Titan could have taken the shuttle's cargo role at one tenth the cost, and Soyuz modules could handle the crew duties of the shuttle, again at one tenth the cost.

 

and if you could actually pack an entire space station into three Saturn V payloads in the first place (problematic because you're ignoring the problem that you're launching volumes as well as weights)

One word: Skylab. A space station launched by a Saturn V.

 

then NASA could have shaved $50 billion off the $150 billion cost of the space station.

Or more. Under the assumption that orbital assembly is difficult, and it is, one would think it would be cheaper to produce two berthing ports rather than THIRTY. NASA would have saved at least 50 billion.

 

The fact that they didn't do this is then proof that it isn't really serious about space' date=' but rather wanted to bankrupt the Soviet Union and provide more space industry work for congressional constituents?[/quote']

No, the fact that they didn't cancel the shuttle program once its only actual purpose had been automated in 1985 is a good indicator, though. The ISS evolved from the Space Station Freedom concept (coincidentally announced in 1984) which was directly designed to give the shuttle something to do.

[Lawnmower Boy]

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Second most. The Shuttle was worse.

 

 

The Shuttle costs 50% MORE per launch than the Saturn V! The already existing Titan could have taken the shuttle's cargo role at one tenth the cost, and Soyuz modules could handle the crew duties of the shuttle, again at one tenth the cost.

 

 

One word: Skylab. A space station launched by a Saturn V.

 

 

Or more. Under the assumption that orbital assembly is difficult, and it is, one would think it would be cheaper to produce two berthing ports rather than THIRTY. NASA would have saved at least 50 billion.

 

 

No, the fact that they didn't cancel the shuttle program once its only actual purpose had been automated in 1985 is a good indicator, though. The ISS evolved from the Space Station Freedom concept (coincidentally announced in 1984) which was directly designed to give the shuttle something to do.

 

From the top: the space shuttle was approved (i) because it had lower payload recurring costs than existing and proposed expendable launch vehicles; and, (ii) because it relaxed volume constraints on payloads. Per Wikipedia: "The crucial factor in the size and shape of the Shuttle Orbiter was the requirement that it be able to accommodate the largest planned commercial and military satellites, and have the cross-range recovery range to meet the requirement for classified USAF missions for a once-around abort from a launch to a polar orbit." I note, too, that the specification saw it as comparing favourably to existing systems on payload-by-weight as well. This obviously discounts a follow-on production order for Saturn Vs, but nicely underlines the fact that while the Saturn V was an impressively big weight lifter, it was also a somewhat crazy technological system.*

 

Using payload recurring costs foregrounds the issues of payload design and of achieving economies of scale. The first puts in the realm of satellite engineering, ignored by your post. Many of the hoped-for gains here were not actually achieved, but, as far as I'm aware, some were. I'm sure that you have a vast literature to draw on in refuting NASA's belief that larger payload bays reduce costs for satellite designers, and would welcome hearing it. Economies of scale arise from the lower fleet operating costs of a reusable vehicle. The more the space shuttle is used, the lower will be the sunk costs of R&D and manufacture. Thus, the space shuttle failed to deliver the full measure of anticipated economies, as there weren't as many launches as hoped. From this we get Roger Pielke's famous global estimate of $1.5 2008 dollars per space shuttle launch, comparing unfavourably to the oft-cited $1.1 billion 2012 dollars, obtained by applying an inflation multiplier to the 1970 estimate in the NASA study already linked. This, however, puts us in the land of accounting, where it is perfectly possible to assess the cost per launch of a space shuttle as low as $100 million (1990) dollars, or split the difference at $300 1990 millions, as this source does.

 

Is the Space Shuttle cheaper than the Saturn V? You say "no," but some people are prepared to say "yes," and, given their different roles, it is not a straightforward argument. That being said, it doesn't matter. NASA went to the space shuttle believing that it would be cheaper than the Saturn, and do things that Titan couldn't. It ended up being committed to the Space Shuttle for the long haul. That's history. You're free to second guess it. That will lead to better outcomes next time. It's the conspiracy talk, according to which the Space Shuttle was a sinister plot to throttle the space programme by throwing money away on the space programme that's the issue here.

 

Moving on, I'll take this occasion to point out that you can't compare Skylab to the International Space Station. Or claim that that the "only purpose" of the Space Shuttle was "automated" in 1985 without explaining what you're talking about. We put humanoid androids in space in 1985? Why wasn't I told?

 

Finally, is there any reason outside of tinfoil hat country to think that the ISS was some sneaky attempt to "bankrupt the Russians?" I need this explained to me very, very clearly, because I'm still not getting it. I do get that some people are aggrieved that Space Station Freedom was cancelled in favour of the ISS. Some of them are the same people that are aggrieved that the United States didn't put x-ray lasers in orbit in 1988. The fact that crazy people agree with you doesn't make your argument stronger. Other people think that ...what, building a space station was a makework project for the space shuttle? This is a long and open-ended process of research and development. We don't have a "purpose" for manned space flight yet. We're doing it anyway, because we expect that it will be useful in the end. Manned spaceflight with Saturn V follow-ons would have "needed a purpose," too. Again, not to call back other recent controversies around here, there wasn't much that manned space flight could do after Apollo than a space station. I'm sorry that the space station disappointed you. Remember that there was a time....

 

Let's drop the wrangle over cost-benefit analysis. This is a bog-standard argument in technology policy. We have the government doing one thing, and critics lining up on the sidelines to proclaim that their ideas are better, and thus that the government is motivated by an evil conspiracy, or that they're a bunch of technological reactionaries who, because of their incomprehensible ebilness, hate steam engines/difference engines/small tube boilers/zeppelins/flying wings/what have you. Not helpful.

 

 

 

 

*Remember that the Saturn V catastrophic failure case is equivalent to blowing up a low-level nuclear bomb in the middle of Cape Canaveral, and that there were two partial failures (Apollo 6 and 13) out of 15 Saturn V launches. Smaller rockets, smaller payloads, also smaller booms.

[megaplayboy]

Re: More space news!

 

One way to think about it is in terms of incremental permanence:

1) a semi-permanent presence in LEO

2) a permanent presence in LEO, or a semi-permanent one in GEO

3) a permanent presence in GEO(this would actually be a huge breakthrough, imo)

4) a semi-permanent presence on the Moon, or at a Lagrange point

5) a permanent presence on the Moon/Lagrange point

6) a semi-permanent presence on Mars

7) a permanent presence on Mars

8) semi-permanent: Titan, Europa(maybe)

9) permanent: Titan, Europa

10) semi-permanent: Pluto, outer perimeter of Solar System

11) permanent: Pluto/outer perimeter

12) S-P: Oort

13) P: Oort

14) S-P: Any nearby star system

15) S-P: Any nearby star system with a remotely habitable planet

16) P: Any nearby star system with a remotely habitable planet

 

The problem is in thinking we can just go 1. Moon Colony, 2. Mars landing, 3. Mars colony, 4. Planet X colonization, and thinking this can all be done in a matter of a few decades. We should be thinking and planning in terms of centuries. Having a permanent presence in GEO would take 20-50 years. A lunar colony might take 30-60 years. One on Mars might take 100 years. It could take 2-400 years to put a permanent space station on the outer perimeter of our Solar System, or in the Oort Cloud. And it might take 1000 years to actually get to the penultimate goal, a permanent presence on a habitable planet in another star system(the ultimate goal, one assumes, would be peaceful contact with sapient alien life).

 

It's not like humanity's inclined to just give up on the idea of space travel any time soon.

[McCoy]

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Telescopes Team Up to Give Us Our First Real Look at a Black Holehttp://www.pcworld.com/article/248286/telescopes_team_up_to_give_us_our_first_real_look_at_a_black_hole.html

In the coming months, astronomers and radio telescopes around the world will unite to look into and take the first-ever photo of a black hole.

 

The Event Horizon Telescope Project hopes to be the first to truly observe a black hole, which was impossible until now. Scientists say that the latest developments of (sub)mm Very Long Baseline Interferometry (VLBI) make it actually possible to generate an image of a black hole. The VLBI technique uses multiple telescopes to observe the same body in space to emulate the power of much larger telescope.

 

So far, we’ve only been able to imagine what a black hole looks like through artist renderings and CGI. In order for us to see anything in space, it needs to emit light, and black holes actually absorb light. What little, faint radio emissions we can see from black holes also ends up getting distorted and reflected by the debris swirling around the event horizon.

 

But with a large array of telescopes, the scientists can pull a few tricks to increase the system’s resolution and observe finer details in the emissions. The system of telescopes will be looking at the black holes with two polarizations to see more of the energy spectrum. The telescopes can also combine their sensitivities to radio signals to effectively increase the system’s aperture and imitate a larger telescope.

 

The project will use over 50 radio telescopes around the world to get a closer look at the nearest massive black hole, Sagittarius A, which is only (relatively speaking) 25,000 light years away and situated near the center of our galaxy. The scientist’s other target is M87, a black hole 53 million light years away that is 6 billion times the size of our sun.

 

The Event Horizon Telescope Project will begin tomorrow, January 18, with a meeting in Tucson, Arizona to discuss the project. The first observational run of the project is scheduled for March 14-22 with four collaborating telescopes: Arizona Radio Observatory/Submillimeter-wave Astronomy near Safford, Airzona; the Combined Array for Research in Millimeter-wave Astronomy in the Inyo Mountains, California; the James Clerk Maxwell Telescope in Hawaii; and The Submillimeter Array in Hawaii.

Now Imagine if we had a radio telescope, even an uncrewed remote controled one, on the Lunar surface for an even longer baseline array.

[Gnaskar]

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From the top: the space shuttle was approved (i) because it had lower payload recurring costs than existing and proposed expendable launch vehicles; and' date=' (ii) because it relaxed [i']volume [/i]constraints on payloads. Per Wikipedia: "The crucial factor in the size and shape of the Shuttle Orbiter was the requirement that it be able to accommodate the largest planned commercial and military satellites, and have the cross-range recovery range to meet the requirement for classified USAF missions for a once-around abort from a launch to a polar orbit." I note, too, that the specification saw it as comparing favourably to existing systems on payload-by-weight as well.

 

Of course, by '85 (when the early plans for ISS were proposed), each and every one of those points had gone out the window. The lower payload recurring costs were for the fully reusable "B" shuttle, which was never developed (Funding for it was cut). The idea of widening the fairing past the radius of the rocket meant that rockets could launch near arbitrary volumes. The era of 25 ton satellites was long gone. And the shuttle never did manage to launch the required USAF payloads to polar orbit. Neither did it ever live up to the '60s specifications.

 

*Remember that the Saturn V catastrophic failure case is equivalent to blowing up a low-level nuclear bomb in the middle of Cape Canaveral' date=' and that there were two partial failures (Apollo 6 and 13) out of 15 Saturn V launches. Smaller rockets, smaller payloads, also smaller booms.[/quote']

 

The shuttle weighs over 2 kilotons on the pad, compared to the Saturn V's 3 kilotons. The shuttle solid boosters (1.18 ktons) are so volatile that they cannot be stopped once they're active, making them far worse than the propane used by the Saturn V's first stage. If one of those boosters were to trigger early, the whole damn thing would tip over and be dragged across the country at ground level.

 

But all this is arguing over a "and one more thing", while ignoring my main point:

I hate to be Mr. Wet Blanket here' date=' but saying that something that is actually very hard and very expensive would be easy doesn't make it so. The reason that we're not on the Moon right now is that it is precisely a very expensive and complicated place to live. You know, the lack of water? We need to colonise the poles, and that's a hugely expensive rocketry project, leading to the conclusion that we should master orbital refuelling first; leading to the conclusion that we should master living in orbit first; leading to the prioritisation of the ISS.

 

So, by this the plan should be:

step one: Build orbital research facility.

step two: Master living in space.

step three: Master orbital refueling.

step four: colonize lunar poles.

 

so my question is this: Where is step three? For that matter, rather than complaining about the effects of zero gee on the human body, why aren't we testing artificial gravity by rotation? NASA has spent the last forty years listing the technology they would need for the next great mission when explaining why we haven't done it yet, and doing everything in their power to block projects that aim to acquire those technologies. And that, to bring the whole thing back to the beginning, is why China is going to leave you in the dust.

[McCoy]

Re: More space news!

 

One way to think about it is in terms of incremental permanence:

1) a semi-permanent presence in LEO

2) a permanent presence in LEO, or a semi-permanent one in GEO

3) a permanent presence in GEO(this would actually be a huge breakthrough, imo)

4) a semi-permanent presence on the Moon, or at a Lagrange point

5) a permanent presence on the Moon/Lagrange point

6) a semi-permanent presence on Mars

7) a permanent presence on Mars

8) semi-permanent: Titan, Europa(maybe)

9) permanent: Titan, Europa

10) semi-permanent: Pluto, outer perimeter of Solar System

11) permanent: Pluto/outer perimeter

12) S-P: Oort

13) P: Oort

14) S-P: Any nearby star system

15) S-P: Any nearby star system with a remotely habitable planet

16) P: Any nearby star system with a remotely habitable planet

Make 5) a permanent presence on the Moon & Lagrange point(s), O'Neil habitats

 

Add 7.5) O'Neil habitats in the belt

[tkdguy]

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More Lunar Ice Found

[Old Man]

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So, by this the plan should be:

step one: Build orbital research facility.

step two: Master living in space.

step three: Master orbital refueling.

step four: colonize lunar poles.

 

I wonder if it wouldn't be easier to replace step four with a Mars colony. It's much further, but it also seems easier to set up a colony on a body that has some atmosphere as well as greater quantities of water ice. Eventual terraforming of Mars also seems like a feasible, if very long-term, goal--more so than trying to terraform the moon at least.

[McCoy]

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I wonder if it wouldn't be easier to replace step four with a Mars colony. It's much further' date=' but it also seems easier to set up a colony on a body that has [i']some[/i] atmosphere as well as greater quantities of water ice. Eventual terraforming of Mars also seems like a feasible, if very long-term, goal--more so than trying to terraform the moon at least.

Can we define colonize/colony in this context? Permanent infrastructure with rotating personnel? People intentionally making a one way trip? People going with the intent of having/raising kids there?

[Cancer]

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Actually, I think the real stepping stone to greater access to anywhere off-Earth is to establish and maintain the ability to assemble (with full reliability) spacecraft in a facility in Earth orbit. Right now literally everything is assembled in toto on the ground, then lifted up. That imposes absolute upper limits to the mass of anything you send anywhere, because the energy price to Earth orbit is unavoidable, and that price corresponds to the payload limit of the launch vehicle. ISS is not that facility now, and no one that I have heard of has addressed what it takes to make that facility. But that's what it's going to take to build the ship that would carry humans to Mars, or an asteroid, and it's probably what it would take to establish a semi-permanent base on the Moon. But I don't see any willingness to pay for such a facility at this time.

[SteveZilla]

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Actually' date=' I think the real stepping stone to greater access to anywhere off-Earth is to establish and maintain the ability to assemble (with full reliability) spacecraft in a facility in Earth orbit. Right now literally everything is assembled in toto on the ground, then lifted up. That imposes absolute upper limits to the mass of anything you send anywhere, because the energy price to Earth orbit is unavoidable, and that price corresponds to the payload limit of the launch vehicle. ISS is not that facility now, and no one that I have heard of has addressed what it takes to make that facility. But that's what it's going to take to build the ship that would carry humans to Mars, or an asteroid, and it's probably what it would take to establish a semi-permanent base on the Moon. But I don't see any willingness to pay for such a facility at this time.[/quote']

 

But even if it is assembled in orbit, any parts that are boosted up from Earth still have to pay that energy price to Earth orbit. Would it make more sense to have the spaceyard in Lunar orbit, using parts boosted up against the much weaker lunar gravity?

[Cancer]

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Yes, you still have to boost parts to orbit. But if you can assemble in orbit, then to get a spacecraft that can carry and support 50 people in interplanetary space for three years with adequate radiation shielding, you don't have to have a booster big enough to lift the assembled ship off Earth (or Moon, though the energy price to lift off from the Moon is obviously less). And, frankly, that 50 people for three years is roughly what I think a viable humans-to-Mars-and-back mission ought to look like.

[megaplayboy]

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Well, without orbital assembly, even a there-and-back Mars Mission would likely require the equivalent of 3 Saturn Vs per mission(one to send the facility, one to send the men, and one for the return flight). If you could build in orbit, maybe you could do it in one flight. I'm guessing even with orbital assembly and refueling, a manned flight to the outer periphery of the solar system would involve a multi-kiloton vehicle, and going outside the solar system to colonize another world would involve a multi-megaton (or more) vehicle, something well beyond our current capacities.

[Lawnmower Boy]

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But even if it is assembled in orbit' date=' any parts that are boosted up from Earth still have to pay that energy price to Earth orbit. Would it make more sense to have the spaceyard in Lunar orbit, using parts boosted up against the much weaker lunar gravity?[/quote']

 

 

Manufacturing components of the kind required is a very complicated business that requires an integrated industrial complex. The way we do it right now just assumes the availability of air, water, and free life support, too. So parts pretty much have to come from Earth for the foreseeable future, I'd think. Reaction mass is entirely another matter. The crazy part of the big projects has always been the amount of rocket fuel we end up lifting into orbit. Unlike integrated circuits and titanium rods, there's plenty of oxygen and hydrogen up there.

 

Make no mistake about it. It's a hugely ambitious target going forward from where we are right now to turn space-sourced ice into liquid hydrogen and oxygen. But that, in my opinion, is an argument for this idea. We have a road ahead. We get the ice from asteroids, probably. They have much easier access energetics than either the lunar poles or Mars. We bring it back to Earth orbit, and process it at ISS3.0. At one generation for each iteration of the ISS, that puts our timeframe for a Mars exploration ship out to 2050.

 

I know that this sounds hugely unambitious compared with Moon colony 2020, Mars colony 2050, Alpha Centauri colony 2100. The thing is, it's doable. Every step along the way allows for fumbling, experiments, missteps, and technological disappointments. We can fiddle with tethers or spaceplanes or electromagnetic launchers or what have you along the way, and not worry if they're individually disappointing. Each step permanently expands humanity's capabilities in space. Each step also maintains a steady flow of spending on the Earth-based space exploration infrastructure, maintaining a viable political base for continuing exploration. Hopefully, we'll see spin-offs along the way that turn into viable space-based activities in their turn.

 

Or, you know, we'll be launching a Neutrino Drive FTL spaceship to seek out the Ancients by then.

[McCoy]

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Yes' date=' you still have to boost parts to orbit. But if you can assemble in orbit, then to get a spacecraft that can carry and support 50 people in interplanetary space for three years with adequate radiation shielding, you don't have to have a booster big enough to lift the assembled ship off Earth (or Moon, though the energy price to lift off from the Moon is obviously less). And, frankly, that 50 people for three years is roughly what I think a viable humans-to-Mars-and-back mission ought to look like.[/quote']

50 people? I'll never accuse you of thinking small!

 

While I am on record as saying the six-people-in-an-efficency-apartment-for-three-years model would more-likely-than-not end in homocide, think we might be able to do it with fewer than 50.

 

(My solution was send two ships, three people per ship. Once on Mars they find infrastructure ready, built by telepresence from parts sent on uncrewed missions. Everyone has their own room while on planet, and (especally for the first few months) works most closely with someone from the other ship.)

[Old Man]

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But even if it is assembled in orbit' date=' any parts that are boosted up from Earth still have to pay that energy price to Earth orbit. Would it make more sense to have the spaceyard in Lunar orbit, using parts boosted up against the much weaker lunar gravity?[/quote']

 

Only if those parts are constructed on the moon.

 

I sort of question the need for any kind of orbital "construction facility". Once you put something up in orbit it pretty much stays there. You wouldn't need a facility so much as a loose grouping of whatever assembly robots you need to stick the pieces together. The exception might be if a significant portion of the assembly requires human labor. Then you would need a habitat for the humans to operate out of long term.

[SteveZilla]

Re: More space news!

 

Only if those parts are constructed on the moon.

 

I would think that would have been a given -- otherwise, that would make it look like I was saying we should ship the parts from Earth Surface, to Moon Surface, then *back* to Moon Orbit.

 

I sort of question the need for any kind of orbital "construction facility". Once you put something up in orbit it pretty much stays there. You wouldn't need a facility so much as a loose grouping of whatever assembly robots you need to stick the pieces together. The exception might be if a significant portion of the assembly requires human labor. Then you would need a habitat for the humans to operate out of long term.

 

(Bolded for emphasis) Based upon what I have seen with the Hubble, ISS, Mir, and Skylab, IMO it would be pretty much a requirement to have at least a couple humans on location, with the rest of the "workforce" being automation/telepresence. Thus, some minimal habitation requirement. Not necessarily occupied full-time, just while there is a construction project going.