Will manned space exploration die with the space station?

[Ranchoth]

I think practicality is going to have very little to do with further manned space travel, knowing human nature…it’s not exactly practical to pile up five and a half million tons of limestone to hold one dead man, but they still did it.

I think it’ll really depend on whoever has enough money, the hunger for their share of glory and/or a big-ass distraction, and very little obligation to secure wide support for any of it.

Thus, the next person to walk on the moon, I predict, will be working either for super rich nerds, or the PLAAF.

When we get some super-rich nerds from China, of course, things are going to get really interesting…

[pancakes3]

to piggyback off what “Lust4Life” said, an old philosophy professor of mine used to say quite often “you can tell a lot about a civilization based on where the jobs are” meaning high-paying jobs. currently in america? doctors, lawyers, and finance. engineers are an afterthought and it shows in our undergraduates. china and india are churning out way more engineers than we are, even per capita. you cut government funding to research institutions like NASA (or the NIH, or other national labs) and you’re doing the nation a great disservice. the funding is a drop in the bucket compared to what we spend on defense (makes me vomit in my mouth every time i think of the defense budget) and yet people question the practicality of NASA all the time with nary a word about the trillions of dollars of rusting military wares we’ve got sitting around.

[Lumpy]

My Sunday paper had an article that NASA is considering having the next phase of manned exploration be an asteroid rendevous. Makes a certain kind of sense; without the need for braking into orbit around a massive body or a lander, the mission requirements are smaller, and it would be a good dry run for a Mars mission.

[Hyperelastic]

@pancakes3

to piggyback off what “Lust4Life” said, an old philosophy professor of mine used to say quite often “you can tell a lot about a civilization based on where the jobs are” meaning high-paying jobs. currently in america? doctors, lawyers, and finance. engineers are an afterthought and it shows in our undergraduates. china and india are churning out way more engineers than we are, even per capita. you cut government funding to research institutions like NASA (or the NIH, or other national labs) and you’re doing the nation a great disservice. the funding is a drop in the bucket compared to what we spend on defense (makes me vomit in my mouth every time i think of the defense budget) and yet people question the practicality of NASA all the time with nary a word about the trillions of dollars of rusting military wares we’ve got sitting around.

Your professor made an astute observation, but you must realize that the “defense” budget isn’t just bullets and combat boots. There’s all kinds of stuff in there, from medicine to biofuels to computer networking. DOD-funded research was the main impetus for the development of both microprocessors and the internet.

DOD supports a larger space program and more fundamental research than NASA. In fact, Apollo probably would not have made it to the moon by 1969 if DOD hadn’t started funding the F-1 engine in 1955.

DOD provides a convenient vehicle for Congress to fund pet projects both worthy and idiotic, while all the time appearing to be pro-military.

Re the OP, human spaceflight is on its knees and will not happen again in the US for at least 20 years.

[HopDavid]

@Stranger_On_A_Train

This uses predominately space-extracted resources for the basic structure (water, silicon, and air from near Earth asteroids, terrestrial carbon fiber),

Why do you believe such resources from near Earth asteroids are more accessible than the same resources from the moon?

[Lumpy]

@HopDavid

Why do you believe such resources from near Earth asteroids are more accessible than the same resources from the moon?

Asteroids are more likely to consist of either iron-nickel that can be used with minimal refinement, or carbonaceous chondrites that have a lot more carbon, hydrogen and nitrogen than what we expect the lunar surface can provide. When the “High Frontier” concept of cislunar space colonies was in vogue, the step beyond establishing the colony-powersat system was expected to be reducing dependence on volitiles exported from Earth by obtaining them from near-Earth asteroids.

[billfish678]

@HopDavid

Why do you believe such resources from near Earth asteroids are more accessible than the same resources from the moon?

Two things.

IIRC there are literally a hundred (or was it a thousand?) asteroids currently known that are easier energy wise to reach than the moon/moons surface.

Also, various asteroids are likely to be quite rich in various materials. One will be quite rich in one thing, one in yet another and so on and so on. Given how the moon formed and evolved, I doubt the moon is rich in much of anything. Or in other words you’ll have to process a butt load of random moon material to get what you want.

[HopDavid]

@Lumpy

Asteroids are more likely to consist of either iron-nickel that can be used with minimal refinement,

Takes about 10 km/sec to get to Low Earth Orbit. Another 4 km/sec or so to reach an NEO. Tsiolvovsky’s rocket equation plus a 14 km/sec delta V budget mandates a multi-stage expendable rocket. “Expendable” is another word for “disposable”.

I don’t care if an asteroid’s solid platinum or solid crack cocaine. Bringing the resource back to an earth market would lose money.

Further, of the many craters on the moon’s surface, it is likely many of these were from iron nickel meteorites.

@Lumpy

or carbonaceous chondrites that have a lot more carbon, hydrogen and nitrogen than what we expect the lunar surface can provide.

The elevated CPR from Chandrayaan 1’s radar seems to indicate sheets of relatively pure ice two or more meters thick.

The LCROSS ejecta was about 20% volatiles. Much of the volatiles were carbon and nitrogen compounds as well as water.

It is likely there is abundant carbon, hydrogen and nitrogen at the lunar poles.

[HopDavid]

@billfish678

Two things.

IIRC there are literally a hundred (or was it a thousand?) asteroids currently known that are easier energy wise to reach than the moon/moons surface.

Delta V is an important metric, but not the only one. Frequency of launch windows is important. Also trip time.

Unfortunately, low delta V asteroids generally mean rare launch windows.

Launch windows generally occur each synodic periodic.
Synodic period = | (period 1 * period 2) / (period 1 - period 2) |

The nicest delta V asteroids have the most earthlike orbits. Those having a semi-major axis close to one astronomical unit will also have a period close to one year.

Let’s say our NEO had a period of 1.1 years. (1.1 * 1) / (1.1 - 1) is 11 years.

In contrast, from a given low earth orbit, launch windows to the moon open each two weeks.

Trip time to an NEO are generally 6 or more months. Trip time to the moon is 3 days.

@billfish678

Given how the moon formed and evolved, I doubt the moon is rich in much of anything.

A questionable assumption. Please see my reply to Lumpy.

[billfish678]

@HopDavid

Takes about 10 km/sec to get to Low Earth Orbit. Another 4 km/sec or so to reach an NEO. Tsiolvovsky’s rocket equation plus a 14 km/sec delta V budget mandates a multi-stage expendable rocket. “Expendable” is another word for “disposable”.

I don’t care if an asteroid’s solid platinum or solid crack cocaine. Bringing the resource back to an earth market would lose money.

Further, of the many craters on the moon’s surface, it is likely many of these were from iron nickel meteorites.

The elevated CPR from Chandrayaan 1’s radar seems to indicate sheets of relatively pure ice two or more meters thick.

The LCROSS ejecta was about 20% volatiles. Much of the volatiles were carbon and nitrogen compounds as well as water.

It is likely there is abundant carbon, hydrogen and nitrogen at the lunar poles.

Point one. Whats your point? Besides throwing out the number 10 and 14?

There’s two things here. Value to return to Earth or value of use in space.

Did those nickle iron fellows soft land on the moon’ surface to make the pickings easy?

That lunar ice layer, carbon, hydrogen, and nitrogen may be there and may be nice. But ,then again an asteroid thats easier to get to may have the same stuff means the moon is still/mabe a second rate resource wise.

[billfish678]

While you may disagree with me, HopDavid, you haven’t told me anything I didnt already know. So, its obvious to me that you are weighing the importance of various things differently or are making different assumptions about what is or isnt or important.

[HopDavid]

@billfish678

Point one. Whats your point? Besides throwing out the number 10 and 14?

Given propellant at EML1 and LEO, it may be possible to reach asteroids in reusable space ships. From EML1 an asteroid might be reached with as little as 1 km/sec delta V.

But unless there’s propellant at these locations, they’re not reachable with anything but costly disposable rockets.

Here is a delta V map of our neighborhood:

http://clowder.net/hop/TMI/CislunarFuelDepot.jpg

You will notice that lunar propellant is much closer to EML1 and LEO than earth’s surface.

@billfish678

There’s two things here. Value to return to Earth or value of use in space.

Without propellant at various locations in earth’s gravity well, transportation beyond Low Earth Orbit remains very difficult and cost prohibitive for any business ventures hoping to realize a return on investment.

@billfish678

Did those nickle iron fellows soft land on the moon’ surface to make the pickings easy?

Impact velocities could range from 70 km/sec to just over lunar escape (2.4 km/sec). I believe it’s quite possible for some of the slower moving monolithic iron nickel meteorites to have left minable deposits in the craters.

@billfish678

That lunar ice layer, carbon, hydrogen, and nitrogen may be there and may be nice. But ,then again an asteroid thats easier to get to

Are you insisting that delta V is the only metric?

Since you seemed to have missed it earlier, I repeat some other metrics and elaborate on them.

RARITY OF LAUNCH WINDOWS
Establishing mining infrastructure will take repeated trips. Having a launch window each decade or so would slow development past many election cycles and past the life span of potential investors.

TRIP TIME
To the moon is 3 days. On the rare occasions a launch window opens, it will take half a year or so to get to an NEO.

Have you heard of GCR and SPE? During the trip out there, the space ship will not enjoy frequent supply and maintenance trips as the I.S.S. does. Given our present state of the art, a 6 month trip is very likely to kill the astronauts.

@billfish678

may have the same stuff means the moon is still/mabe a second rate resource wise.

May is the operative word here. Carbonaceous chondrites likely have water in the form of hydrated clays. They’re water rich in the same fashion the concrete in a sidewalk is water rich. There are likely extinct comet NEOs that have water ices in their interior. But so far we haven’t discovered them.

On the other hand, we know exactly where the lunar craters with the anomalous CPR are.

[Stranger_On_A_Train]

@HopDavid

I don’t care if an asteroid’s solid platinum or solid crack cocaine. Bringing the resource back to an earth market would lose money.

Further, of the many craters on the moon’s surface, it is likely many of these were from iron nickel meteorites.
…
It is likely there is abundant carbon, hydrogen and nitrogen at the lunar poles.

You seem to be talking across yourself; if the amount of impulse required to reach and extract resources from a Near Earth Asteroid is cost- and technology-prohibitive, then mining resources on the surface of the Moon, extracting chemical propellants from the Lunar poles (which are the most difficult areas of the Moon to land upon), and returning said resources to the Earth’s surface is even more prohibitive, even without consideration for the difficulties in operating equipment in the Lunar dust. (See The Effects of Lunar Dust on EVA Systems for a summary of different issues, not withstanding astronaut health.)

You also seem to be missing the essential point that aside from a few scarce materials (such as copper or the rare earths) the value of extracting space resources in situ is not cheaper than terrestrial mining, but that it does less environmental damage, and that it may make it cost effective to develop a sustainable human presence in space, i.e. not having to ship materials and manufactured goods from Earth to orbit. The chicken-and-egg problem is that you will have to first develop the kind of infrastructure to support the resource extraction. By using resources that are readily available and require little in the way of refining and fabrication. The “Easter Egg” habitat I outline above doesn’t require the fabrication of sheet metal, float glass, fasteners, and other process-intensive products; it allows for the use of resources in an essentially elemental state, and thus reduces both the manufacturing cost and the threshold of infrastructure (either launch or in situ manufacturing) needed to support habitat construction.

As for propulsion, while chemical combustion will likely remain the standard means of going from surface to orbit for the foreseeable future (short of controlled thermal fusion or some kind of space elevator, both of which are far enough distant from existing capability that we cannot project when or if they may be feasible), spacecraft propulsion should move to higher propellant efficiency technology, such as the various forms of ion engines, nuclear thermal engines, or fission salt/fragment rockets. The mass, tankage, handling problems, and limited scalability of chemical propulsion is inadequate for moving large masses around in space. Cheaper access from ground to space is feasible using a combination of practical reusability and cheap expendable systems; Robert Truax’s Sea Dragon concept (which was actually demonstrated as a proof of concept in the See Bee and Sea Horse vehicles) offered a workable Big Dumb Booster that had the genuine potential of reducing launch costs by more than an order of magnitude and increasing the predicted reliability for superheavy lift (by reducing system complexity and increasing structural and thermal margins).

Stranger

[aceplace57]

I’m too lazy to look it up. But, there’s a long list of consumer products that benefited from the space program. The space program has always pushed technology to the absolute limits.

We’re disbanding an incredible pool of workers that can never be replaced. You don’t find people with these skills & education anywhere else.

I doubt the U.S. will ever return to any significant space program. A shame because the rest of the world will pass us by. Not just in space but in science and technology. We won’t be at the forefront any longer.

[HopDavid]

@Stranger_On_A_Train

You seem to be talking across yourself;

When I say delta V is not the only metric, I seem to be talking into thin air.

Please reread what I’ve written.

[Stranger_On_A_Train]

@HopDavid

When I say delta V is not the only metric, I seem to be talking into thin air.

Please reread what I’ve written.

Yes, I have read your claims. I am familiar with the processes involved in mission planning and trajectory trade studies for ballistic, orbital, and trans-orbital missions. I understand your claim that resources on the Moon are more accessible on a frequency basis than many Near Earth Objects. Underlying that assumption is that the mode of operation for such resource extraction would be to launch a mission, land on the Moon, frantically extract the necessary resources, turn around, and fly back, using conventional chemical propulsion technology, and of course ignoring the difficulties of operating on the Lunar environment experienced by the Apollo lunar surface missions as described in the earlier link.

What you are missing is that the essential thrust of this thread is in regard to long term sustainable habitation. In the case of extracting resources and constructing a large space habitat, I don’t care if the trajectory window only allows a yearly transit; I’m not intending to send astronauts back to Earth every couple of weeks to freshen up, and the ultimate goal is to extract resources and perform refining and manufacturing in situ, delivering whatever mineral or manufactured item payloads back to Earth on low energy transfers, or use the capability to provide further inhabitable real estate in space. I would agree that the ability to do so is beyond the current state of the art in qualified or demonstrated propulsion and habitation technology. This applies equally to orbital habitats or a manned presence on the surface of the Moon (or any other planet).

However, I have presented a concept for providing a habitat that uses readily available resources to provide terrestrial-like conditions, including atmospheric pressure, simulated gravity via inertial forces, controlled sunlight and hydrological cycles, protection from radiation (including ionized solar and cosmic gamma radiation) comparable to that of Earth, robustness against ballistic hazards, and sufficient space for agriculture or aquaculture. Although the construction of such an artifact would be an enormous engineering challenge, it doesn’t require any fundamental breakthrough in materials or resource extraction technology, and in fact doesn’t require any material capabilities that don’t already exist.

There would be no way to create comparable conditions on the surface of the Moon (particularly gravity) for the same amount of effort and cost, and regardless of what kind of trajectory you select, you have the cost of lifting material up from the lunar surface, which requires not only a fixed amount of impulse per payload, but also high thrust to combat gravity losses before achieving orbit, while material extracted from space resources can be moved into an Earth-intercept trajectory by the application of gentle constant thrust provided by ion propulsion powered by solar or nuclear fission, and using charged waste material as propellant, all at the leisure of orbital mechanics.

Stranger

[HopDavid]

@Stranger_On_A_Train

Yes, I have read your claims.

Again, here are my “claims”:

Launch windows to the moon open each two weeks.
Trip time to the moon is less than a week.

Low delta V launch windows to an NEO open once each several years.
Trip time to an NEO is months.

Do you dispute these “claims”?

@Stranger_On_A_Train

and of course ignoring the difficulties of operating on the Lunar environment experienced by the Apollo lunar surface missions as described in the earlier link.

One of your chief objections is the abrasive lunar dust. Earthly grains of dust are jostled around by the wind and rain. Being constantly bumped against one another, the sharp edges are rounded off.

Having no atmosphere or liquid bodies of water, lunar dust keeps it’s sharp edges.

However asteroids also don’t have wind or water currents to round off their dust grains. But you seem to know that NEO dust is non-abrasive. How, exactly?

@Stranger_On_A_Train

What you are missing is that the essential thrust of this thread is in regard to long term sustainable habitation.

Contrary to your wishful thinking, converting an asteroid into a massive spinning balloon hab would require massive infra structure.

Just the water alone is a large problem. Most “water rich” carbonaceous chondrites are hydrated clays. They’re “water rich” in much the same way sidewalk concrete is “water rich”.

Extracting the needed resources for this massive structure would require major hard rock mining infrastructure.

How are you going to move all this material around? Conventional earth moving equipment and shovels would be completely useless. This type of microgravity civil engineering will require acquisition of (costly) experience.

@Stranger_On_A_Train

In the case of extracting resources and constructing a large space habitat, I don’t care if the trajectory window only allows a yearly

“Yearly”?

Yearly NEO launch windows are optimistic. Please reread what I wrote.

@Stranger_On_A_Train

transit; I’m not intending to send astronauts back to Earth every couple of weeks to freshen up, and the ultimate goal is to extract resources and perform refining and manufacturing in situ,

Not only will you have to send astronauts and their life support, but you will also have to send mining and manufacturing equipment, as yet undeveloped micro gravity earth moving equipment, power sources, etc.

Over how many launch windows will you send all this?

A single launch window? To pull this off you’d need to take along some Van Neumann replicating machines with Harry Potter wands. More realistically you would need to send multiple missions over multiple launch windows.

Multiple launch windows requires government support through many election cycles and/or investor support past the life span of an investor.

@Stranger_On_A_Train

delivering whatever mineral or manufactured item payloads back to Earth on low energy transfers,

What sort of fleet of transportation vehicles do you have? What’s the capacity of these “trucks”? Unless you invoke Harry Potter wand waving, you won’t have many and they won’t be large.

If you’re constrained to delivering a two or three “truckloads” each launch window, this vastly constrains possible delivery rates. If rate of delivery is a few truckloads per decade, this will postpone achieving a return on investment.

Not only do rare launch windows slow rate of infrastructure development, they also slow rate of commodity delivery.

@Stranger_On_A_Train

I would agree that the ability to do so is beyond the current state of the art in qualified or demonstrated propulsion and habitation technology.

Many decades, perhaps centuries away.

@Stranger_On_A_Train

This applies equally to orbital habitats or a manned presence on the surface of the Moon (or any other planet).

Wrong.

Some differences between the moon and NEOs.

Trip time: 5 days (vs months)

Launch windows: each two weeks (vs years).

We have good data indicating locations of minable lunar volatiles (vs, as yet, no prospecting data for NEOs).

And another difference I haven’t mentioned yet: The round trip light lag is 3 seconds. The 384,000 km distance also allows higher bandwidth.

Teleoperated mining equipment and earth moving equipment is far more doable on the moon than any other non-earth body. This eliminates the initial need to send up canned meat. (Canned meat is Charlie Stross’ euphemism for humans in habs).

@Stranger_On_A_Train

There would be no way to create comparable conditions on the surface of the Moon (particularly gravity)

So far we have no data on the effects of 1/6 gravity. Your assumption that humans can’t live in it are premature.

Other than that, the lunar CHON resources needed to make habs are much better characterized than any NEO CHON. And the possibility of extracting and manipulating these resources with telerobots makes building lunar habs far more doable.

[Stranger_On_A_Train]

@HopDavid

Contrary to your wishful thinking, converting an asteroid into a massive spinning balloon hab would require massive infra structure.

What “wishful thinking” is that? My statement with regard to the difficulty was

@Stranger_On_A_Train

Although the construction of such an artifact would be an enormous engineering challenge, it doesn’t require any fundamental breakthrough in materials or resource extraction technology,

Please refrain from cherry-picking and attempting to reframe my statements to suit your strawman arguments.

Stranger

[HopDavid]

@Stranger_On_A_Train

What “wishful thinking” is that? My statement with regard to the difficulty was Please refrain from cherry-picking and attempting to reframe my statements to suit your strawman arguments.

Stranger

Then there’s this:

@Stranger_On_A_Train

This uses predominately space-extracted resources for the basic structure (water, silicon, and air from near Earth asteroids, terrestrial carbon fiber), assembled by largely automated processes with minimal manual labor.

So how many missions do you think it’d take? 1, 2, 3? 10?

We have zero experience with resource extraction in zero gravity.

Contrary to your beliefs, unprecedented largely automated equipment for microgravity resource extraction would require many break throughs. And likely many missions before the operation runs smoothly.

If it takes 1 mission, rarity of launch windows is not an issue. Not likely.

More likely it will take 10 missions or more. Once-a-decade launch windows would slow development to a century.

Are rare launch windows an issue or not?

[HopDavid]

@billfish678

While you may disagree with me, HopDavid, you haven’t told me anything I didnt already know. So, its obvious to me that you are weighing the importance of various things differently or are making different assumptions about what is or isnt or important.

If you assign little weight to rare launch windows and long trip times, it is quite obvious we’re weighing things differently.

On your scales, does it matter little that astronauts suffer prolonged exposure to GCR over a journey lasting months?