Stargazing Why Aren't There Telescopes on the Moon?

[tom aaron]

I generally agree with that. Unless we stuff things up completely and destroy our basis for technological development, I see Homo sap as just a passing phase in the development of intelligent communities. All it takes to set it off is the radical development of teleological evolution by technological means. Who knows, we might be able to engineer people with no recurrent laryngeal nerve and who can calculate pi, or even e to the i pi, or their own tax returns, without a calculator... The list of exciting possibilities extends beyond most of our imaginations.

True.

This may be the eve of something big. The issue 'today' is that we just don't know. We make predictions based on what we know today yet at the same time understand that some game changer may happen next decade or next century.

Are we one of the last generations for which death is a certainty? The last generation to not know about some alien intelligences? The last generation not to be aware of some Theory that explains existence?

I think about my father who passed away in the early 1990's. He was very intelligent but never heard the words Internet, Yahoo, Cell phone, Text etc. One has to wonder what technologies are going to take off in the next couple of decades. Virtual something or another...Quantum computing. Things that may be game changers in understanding Cosmology and practical in use in Astronomy.

 

[Jon Richfield]

True.

This may be the eve of something big. The issue 'today' is that we just don't know. We make predictions based on what we know today yet at the same time understand that some game changer may happen next decade or next century.

Are we one of the last generations for which death is a certainty? The last generation to not know about some alien intelligences? The last generation not to be aware of some Theory that explains existence?

I think about my father who passed away in the early 1990's. He was very intelligent but never heard the words Internet, Yahoo, Cell phone, Text etc. One has to wonder what technologies are going to take off in the next couple of decades. Virtual something or another...Quantum computing. Things that may be game changers in understanding Cosmology and practical in use in Astronomy.

There are depths in what you say, Tom. For a long time I have agreed with aspects of John Wyndham's theme in "Trouble with Lichen"; we live lives in which we spend typically say 10% of our time learning and 30% pruning and applying what we have learned and refusing to modify the errors we have learned and 30% decaying (pick alternative thumb suck figures according to personal taste). Not many decades ago I would have said that we need larger, more efficient and more flexible brains and an indefinite lifespan. But I thought in terms of traditional Darwinian and Mendelian biology to attain anything of the type.
Nowadays I would be inclined to think rather in technological directions for achieving something of the kind, and less emphasis on the individual and more in terms of the group. Think of a whole community that could share at least some mental pathways directly. Something like termite colonies, but with the members of the community sharing mental facilities and consciousness rather than blind instincts.
Would politicians love it or hate it? I leave the scenarios open to you!
Good old swarming satellites say I, and down with moon mining! (To show that I am keeping on topic of course. )

 

[selvaarchi]

There is a telescope on the moon. China's lander Chang'e 3 has a 150 mm (5.9 in) Ritchey–Chrétien telescope that will be used to observe galaxies, active galactic nuclei, variable stars, binaries, novae, quasars and blazars in the near-UV band (245-340 nm), and is capable of detecting objects at a brightness as low as magnitude 13. The thin atmosphere and slow rotation of the Moon allow extremely long, uninterrupted observations of a target. The LUT will be the first long term lunar-based astronomical observatory, making continuous observations of important celestial bodies to study their light variation and better improve our current models.(information from Wikipedia)

 

[Jon Richfield]

That is very nice (no irony -- really!) They were doing an exploratory landing and getting their hands into establish a national capability, and why not supply a functional payload while they were at it? Cheaper and more useful than sending humans, for one thing.
I applaud. Genuinely.
But really, irrespective of how functional their 150mm shaving mirror plus comms might be, for the same money they could have flown a very functionally large telescope into LEO or a still respectable observatory into lunar orbit. And such a telescope would have had far more flexibility and longer life than the moon-based jobbie, and a higher probability of success too.
Let us not lose perspective. Putting workstations down on the moon commits us to far smaller and more limited functions than putting them into practical orbits.

 

[rootone]

A telescope on one of the moons of Pluto might be a good idea though.

 

[wabbit]

My favourite is still this one : http://science.nasa.gov/science-news/science-at-nasa/2008/09oct_liquidmirror/

A cryogenic liquid-mirror telescope on the moon to study the early universe

 

[Jon Richfield]

A telescope on one of the moons of Pluto might be a good idea though.

That certainly is true, but why on the moon? Why not in orbit?

Landers on the moons also certainly, but leave the telescopes in the orbits where they can do the most good for the cost.

IMO we should already have suitably purpose-designed observatories around all the major bodies in the solar system and a network of comms relay satellites to serve them.

Our current stone-axe approach not only is a reproach, but may lead to our destruction, and well-deserved too.

 

[Jon Richfield]

My favourite is still this one : http://science.nasa.gov/science-news/science-at-nasa/2008/09oct_liquidmirror/

A cryogenic liquid-mirror telescope on the moon to study the early universe

That undoubtedly is a charming idea, and though I am familiar with the idea of liquid-mirror telescopes, this version certainly is new to me.

But don't ask me to hold my breath for completion of its construction. I still suspect that we could do better with membrane-based telescopes in orbit than trying to create the observatory on the moon.

The least charming aspect of projects like that however, is their all-or-nothing approach: get anything wrong and the whole thing is useless.

Personally I think that we could do far better by exploring the options for telescopes in the L2 regions of various orbiting bodies. All those that I can think of that would be of interest would shelter the observatory from the sun, and observatories that would need sun (perhaps half of them?) could be at L1 points.

Now, I note that the proposed mirror might be as much as 100m diameter. (After all why think small?) It might be a bit challenging to cart up a 100m disk from Earth, so I suppose that the idea is to dig it out of the moon surface and construct the necessary kit in situ. This is not an option in orbit , though we could of course work out a similar concept with film and corrective optics, but I reckon that we could do a lot better by building multi-mirror orbiting telescope arrays with all the tricks of aperture synthesis and possibly adaptive optics etc. (not easy with a rotating fluid mirror!)

And if an entire single telescope died, we still would have a working observatory.

For some purposes we could make 100m look pretty miserly.

And old-fashioned before the moon dish even got made.

And start tomorrow...

 

[selvaarchi]

That is very nice (no irony -- really!) They were doing an exploratory landing and getting their hands into establish a national capability, and why not supply a functional payload while they were at it? Cheaper and more useful than sending humans, for one thing.
I applaud. Genuinely.
But really, irrespective of how functional their 150mm shaving mirror plus comms might be, for the same money they could have flown a very functionally large telescope into LEO or a still respectable observatory into lunar orbit. And such a telescope would have had far more flexibility and longer life than the moon-based jobbie, and a higher probability of success too.
Let us not lose perspective. Putting workstations down on the moon commits us to far smaller and more limited functions than putting them into practical orbits.

What you say is true but in China's case they were going to the moon anyway so this was a bonus. Both China and India already have firm plans to launch space based telescopes separately..

 

[wabbit]

don't ask me to hold my breath for completion of its construction.

Given that it's neither budgeted nor planned as far as I know, this might be wise : )
It's an interesting idea though, with a science case and one for which the moon seems rather uniquely suited. Plus liquid mirrors cost far less than solid ones so the whole thing might even be realistic in terms of cost. I haven't seen more recent publications about this however, so it might indeed remain a nice idea for a long time.

I still suspect that we could do better with membrane-based telescopes in orbit than trying to create the observatory on the moon.

I'm not familiar with these, what are the projects in this area and what kind of specs do they have ?

their all-or-nothing approach: get anything wrong and the whole thing is useless.

How is that different from other space based telescopes or from planetary missions ?

Personally I think that we could do far better by exploring the options for telescopes in the L2 regions of various orbiting bodies. All those that I can think of that would be of interest would shelter the observatory from the sun, and observatories that would need sun (perhaps half of them?) could be at L1 points.

Exploring one option does not preclude others. This one, should it prove workable, may provide a very large mirror more easily than it could be done elsewhere (large in surface area that is - resolution wise, presumably a fleet of spacecraft flying in formation can do a lot better than 100m)

I reckon that we could do a lot better by building multi-mirror orbiting telescope arrays with all the tricks of aperture synthesis

For resolution I completely agree. For collecting area, not so sure.

 

[Jon Richfield]

Given that it's neither budgeted nor planned as far as I know, this might be wise : )
It's an interesting idea though, with a science case and one for which the moon seems rather uniquely suited. Plus liquid mirrors cost far less than solid ones so the whole thing might even be realistic in terms of cost. I haven't seen more recent publications about this however, so it might indeed remain a nice idea for a long time.

Generally agreed. However, in space I suspect that certain classes of telescope could be constructed to be cheaper than liquid.

I'm not familiar with these, what are the projects in this area and what kind of specs do they have ?

None yet. It is my own idea, not yet half-baked. I am still uncertain what the best materials would be, and the best way to shape them. I have ideas on those points, but those are not yet half-baked either. I really mentioned the idea to knock it down mainly, because I have a feeling that to make ANY sort of 100m mirror in space, whether in orbit or on the moon, is a flat invitation to disaster because you will inevitably pick up collisions that would not destroy a crude machine, but would surely mean a short life for a delicate and exposed device like an astronomic mirror. That is why I suggested a modular mirror device instead. More below.

How is that different from other space based telescopes or from planetary missions ?

Not all are different, but large, let alone super-large items like single-mirror telescopes are an extreme example. That is why I dropped the idea of a huge membrane-mirror reflector unbaked. I still remember what happened to Echo,our first successful inflated satellite; it lasted only days or weeks before crumpling. Well, it was just a prototype proof-of-concept device, so that was OK at the time.

Modular devices are not infallible, but they are likely to offer residual function even if say, one mirror survives, or if one telescope in an array gets knocked out, and in fact, could produce useful results from when the first device becomes operational till when the whole array gets retired.

Exploring one option does not preclude others. This one, should it prove workable, may provide a very large mirror more easily than it could be done elsewhere (large in surface area that is - resolution wise, presumably a fleet of spacecraft flying in formation can do a lot better than 100m)

Oh gosh yes! But I am unconvinced that the Lunar giant would be viable at all, though I would not vote against a proof-of-concept toy device of the type; say 1-2 m diameter. After that works properly and satisfactorily, we could explore other toys like 10m jobs. The moon is big enough to support a few I reckon.
Note however that adaptive optic arrays can be made indefinitely large and in space can be pretty light.
In fact, the membrane lens might bake into a good medium for assembling modest-sized components into 100m or even1000m devices. If so, then certain other devices might become practical, such as large-scale 3He collectors, as I hinted earlier in this exchange.
But maybe a membrane lens would prove inferior to a sponge lens. I still am musing about that.
And I still am thinking in terms of modular devices for preference.

For resolution I completely agree. For collecting area, not so sure.

I take your point. In fact I had come to similar thoughts in compiling my previous reply. However, given the ability to assemble anything subtending a sufficient diameter, there is no simple limit to how big an area we could achieve. Even square kilometres, if we let the manufacture and delivery continue long enough; a million1-sq m segments would do it. It would take a long time even with 10-sq m mirrors, but collecting usable data all the time, getting better and better.

 

[mfb]

For that 1 km² project, the secondary mirror should be in the 100 m-range. A few 10 m x 10 m elements won't make a good primary mirror, and you lose even more light at the unfinished secondary mirror.

You probably want to avoid the shadow of Earth due to thermal considerations. Such a thing would experience tidal gravity close to Earth which could make sun-synchronous orbits problematic. In L1 you have the Earth as disturbing bright object, in L2 you have to move the mirror around sometimes to avoid the shadow (Gaia has a limited lifetime due to this). A high Earth orbit could work, or something far away from earth. Certainly a solvable challenge, but scaling things up is not trivial.

 

[Chronos]

Lets not overlook the prospect of erecting a moon based space elevator. That could be a big time game changer.

 

[Jon Richfield]

For that 1 km² project, the secondary mirror should be in the 100 m-range. A few 10 m x 10 m elements won't make a good primary mirror, and you lose even more light at the unfinished secondary mirror.

Thanks, I appreciate these remarks, but would be grateful for a few elaborations (not necessarily detailed, a few hints should be helpful). I accept that a few small elements won't gather as much light as a large mirror, and it might be hellishly hard to control the flock, though it seems to me that they should gather about as much light as the sum of their scattered elements. Also, they should have some advantages over a single mirror with the same area.
However, did you have any other fundamental reason why a few 10 m x 10 m elements won't make a good primary mirror? (I am no expert on astronomic optics!)

You also spoke of "the unfinished secondary mirror"? "secondary mirror" I understand, but "unfinished secondary mirror"? Is that a technical term, or are you referring to its being unfinished in some sense that I missed?

You probably want to avoid the shadow of Earth due to thermal considerations. Such a thing would experience tidal gravity close to Earth which could make sun-synchronous orbits problematic. In L1 you have the Earth as disturbing bright object, in L2 you have to move the mirror around sometimes to avoid the shadow (Gaia has a limited lifetime due to this). A high Earth orbit could work, or something far away from earth. Certainly a solvable challenge, but scaling things up is not trivial.

I was in fact thinking of staying inside the shadow. I realize that working at a few K might be problematic, but I would expect that the constant cold would reduce the thermal cycling problem. For power we then either could use a nearby solar power craft that beams the necessary MW power to the observatory, or we could power the observatory with a few kg of Pu238. Probably the latter would be more practical and less noisy. A worse problem IMO might be the moon barging by every few weeks and causing gravitational disturbances.

I am undismayed by the Earth as a bright object; what you say is true, but the planet would only subtend a degree or two. For most purposes it would be avoidable. The sun though, for an L1 orbit could be a problem, hard to overlook. Of course if we had solar observatories at the L1 points of Earth, Venus, and Mercury (this one would involve some chasing! :) ) they could be immensely valuable and they would present no fuel problems -- ever!

What you say about scaling things up I support heartfeltly!

 

[Jon Richfield]

Lets not overlook the prospect of erecting a moon based space elevator. That could be a big time game changer.

Well, I grant that it would render the problems of establishing a moon-based major observatory negligable, but the only game it would change would be by making any other space-related advances irrelevant forever, because we never could afford them. As destructive social influences go, it would dwarf the Great Pyramid and the tower of babel combined.

 

[mfb]

However, did you have any other fundamental reason why a few 10 m x 10 m elements won't make a good primary mirror? (I am no expert on astronomic optics!)

No fundamental reason, just not much light. If you plan for 10000 segments for the primary mirror and 100 segments for the secondary mirror, 50 segments (~0.5% of the total project) won't give you 0.5 % of the light, but only 25/10000 * 25/100 = 0.0625 % (using 25 for the primary mirror and 25 for the secondary one, let's neglect the others). You get the same amount of light with 7 segments and a smaller design. Aperture synthesis works much better with more segments as well.

Those issues disappear once you have hundreds of segments assembled.

I was in fact thinking of staying inside the shadow.

There is no place of constant shadow* (apart from some valleys on the moon - scnr). All you get at L2 is a partial shadow.

* Sun/Jupiter L2 would be such a point, but that is far away. Not sure about Sun/Mars as the eccentricity of the orbit becomes important there. For circular orbits, the condition is (diameter of sun)/(diameter of planet)*(mass of planet/(3*mass of sun))^(1/3) < 1 which means the planet has to be less dense than 4200 kg/m³ independent of its orbital radius.

 

[wabbit]

Regarding the shadowing, wouldn't it be best to use a separate screen to protect the system from solar radiation and keep it both cool (for cameras etc) and at a constant temperature ? This seems to be the design for the JWST if my understanding is correct.

 

[Jon Richfield]

No fundamental reason, just not much light. If you plan for 10000 segments for the primary mirror and 100 segments for the secondary mirror, 50 segments (~0.5% of the total project) won't give you 0.5 % of the light, but only 25/10000 * 25/100 = 0.0625 % (using 25 for the primary mirror and 25 for the secondary one, let's neglect the others). You get the same amount of light with 7 segments and a smaller design. Aperture synthesis works much better with more segments as well.

Those issues disappear once you have hundreds of segments assembled.

Thanks mfb, that sounds comprehensible and reasonable. Of course, the idea is that the big telescope would be teeeerrriffic when complete and partly useful once the basic structure got past a certain point, even if it would have to advance for a long time before offering better bang for the buck than a few independent baby telescopes. But of course my 1km^2 idea is just an illustrative figure; it is the principle that I was discussing, and your reply did indeed address that principle.
And that principle was in response to the liquid mirror at the lunar pole, which I suspect would cost more than any realistic space rival or group of rivals, and would hardly if ever work at all if it didn't work completely.

There is no place of constant shadow* (apart from some valleys on the moon - scnr). All you get at L2 is a partial shadow.

Mmmm... yes. I hadn't stopped to figure the various penumbral effects. But I reckon that in a lot of cases the penumbra might be desirable, raising the ambient equilibrium temperature from say 3K to say 200K or 250K, far more convenient from the engineering point of view (figures pure thumbsucks of course!) Also of course, I had been far too vague in speaking of L2 points. Generally what I meant was the Earth-moon L2 and the various sun-planet L2 points. The penumbral effects would be drastically different.

But in any case, there are several places where craft could be maintained so as to perform special functions that for the most part would be more expensive or less effective on gravitationally non-negligible bodies. The debacle with the Philae lander was a good example of an unexpected effect that could have turned out a lot worse, but where a non-zero but too-small field caused some serious bother.

 

[jkn]

We need in this order:

1: Cheaper access to orbit. Not much can be be done before this.

2: Permanently manned space station with:
- Radiation protection.
- Energy, air, water and food production.
- Production of basic construction materials: metals, glass, ...

Moon is best place for first station, because of fast escape to Earth and because most work can be done remote controlled from Earth.

After this moon telescopes become reasonable. Heavy parts can be made on the Moon and service is available when something breaks. Again most work can be done by remote control from Earth.

When moon base is well tested, it can be copied to martian moon and to asteroids. Mercury perhaps. Venus no.

 

[tom aaron]

We need in this order:

1: Cheaper access to orbit. Not much can be be done before this.

2: Permanently manned space station with:
- Radiation protection.
- Energy, air, water and food production.
- Production of basic construction materials: metals, glass, ...

Moon is best place for first station, because of fast escape to Earth and because most work can be done remote controlled from Earth.

After this moon telescopes become reasonable. Heavy parts can be made on the Moon and service is available when something breaks. Again most work can be done by remote control from Earth.

When moon base is well tested, it can be copied to martian moon and to asteroids. Mercury perhaps. Venus no.

Made on the Moon! Do you have any idea of the technological infrastructure needed to make some hi tech part for a telescope? Let alone install it. Test it. Remove. Retest, etc.? There is a reason the JWST is a decade behind schedule.

 

[rootone]

Establishing such an infrastucture is not technically impossible, but I think 'It's a waste of time and resources' would be most people's opinion.

 

[Chronos]

The moon, with its low gravity is still a sensible location for a scope despite all the naysayers who complain about technology issues and cost. We already heard this drivel during the review for the hubble. I still cling to the idea we can surpass our expectations so long as we have faith in our children. Our purpose is to give them vision, hope and the benefit of our knowledge..

 

[Jon Richfield]

We need in this order:

1: Cheaper access to orbit. Not much can be be done before this.

2: Permanently manned space station with:
- Radiation protection.
- Energy, air, water and food production.
- Production of basic construction materials: metals, glass, ...

Moon is best place for first station, because of fast escape to Earth and because most work can be done remote controlled from Earth.

After this moon telescopes become reasonable. Heavy parts can be made on the Moon and service is available when something breaks. Again most work can be done by remote control from Earth.

When moon base is well tested, it can be copied to martian moon and to asteroids. Mercury perhaps. Venus no.

Generally I agree, though in that prospectus there still is no short-to-medium-term prospect of moon telescopes being as cheap or as valuable as in space.
Secondly, if we take a long view, both Mercury and Venus would be far and away the most promising real estate in the solar system (mmmm... with the possible exception of some asteroids I guess...). But even then, speaking strictly of astronomy, space telescopes in free orbit remain the most promising options in space.

 

[jkn]

Made on the Moon! Do you have any idea of the technological infrastructure needed to make some hi tech part for a telescope? Let alone install it. Test it. Remove. Retest, etc.? There is a reason the JWST is a decade behind schedule.

That's why I wrote: Heavy parts can be made on the Moon. There is no point trying to make all parts on the Moon.
JWST cannot be completely tested before launch. After launch it cannot be fixed. This greatly increases cost and build time.

First we need cheaper access to orbit. Then infrastructure on the Moon.

 

[tom aaron]

That's why I wrote: Heavy parts can be made on the Moon. There is no point trying to make all parts on the Moon.
JWST cannot be completely tested before launch. After launch it cannot be fixed. This greatly increases cost and build time.

First we need cheaper access to orbit. Then infrastructure on the Moon.

Cheap access to orbit? It's not access to orbit. It's manned presence in space that is expensive...thefails safe infrastructure to support a human. The fuel was less than one thousandth the cost of a Shuttle flight...the rest was making sure astronauts did not die.

Putting some crew on the Moon to install or service a telescope would cost tens of billions of dollars.

 

[Jon Richfield]

That's why I wrote: Heavy parts can be made on the Moon. There is no point trying to make all parts on the Moon.
JWST cannot be completely tested before launch. After launch it cannot be fixed. This greatly increases cost and build time.

First we need cheaper access to orbit. Then infrastructure on the Moon.

That's why I wrote: "in that prospectus there still is no short-to-medium-term prospect of moon telescopes being as cheap or as valuable as in space."
As for "Then infrastructure on the Moon", show us how to do it, really do it, not just thumb-sucking about making giant-scale astronomic hardware from moondust and sunbeams, and then we can get down to discussion.
We have shown how to do space telescopes, launching them up, stuffing them up, fixing them up, and getting mind bending results and huge data output. The Chinese have shown us how to do it on the moon with a shaving mirror as a demo run (more credit to them too!) but they forgot to make the heavy parts on the moon and instead they shipped up the lot. I cannot remember a single instance in which someone launched a space telescope that they then established on a extra-Earth body, much less fabricated it off Earth, so that it rivalled what orbital scopes could do, either for quality, controllability, cost, or duty cycle.
The question is not whether we could if we did and we had, but why we should want to do something hugely expensive on a questionable schedule when we could do something far more than equivalent, far faster, far more cheaply, far less speculatively, and far more usefully. Astronomical observatories on the moon would be non-solutions seeking non-problems.

You say: "JWST cannot be completely tested before launch. After launch it cannot be fixed. This greatly increases cost and build time".
At best all of that applies even more strongly to the moon-pool telescope, and any other substantial lunar-based telescope, and what is more, for JWST it isn't even all true:
you said "After launch it cannot be fixed", knowing full well that Hubble not only got fixed in space, but even got maintained and upgraded in orbit. What possessed you? You knew that perfectly well, right?

 

[jkn]

You say: "JWST cannot be completely tested before launch. After launch it cannot be fixed. This greatly increases cost and build time".
At best all of that applies even more strongly to the moon-pool telescope, and any other substantial lunar-based telescope, and what is more, for JWST it isn't even all true:
you said "After launch it cannot be fixed", knowing full well that Hubble not only got fixed in space, but even got maintained and upgraded in orbit. What possessed you? You knew that perfectly well, right?

What possessed me? Knowledge. I was writing about JWST. See:

http://jwst.nasa.gov/faq_scientists.html

31. Will astronauts be able to service Webb like they did Hubble?

Because Webb, like virtually every satellite ever constructed, will not be serviceable it employs an extensive seven year integration and test program to exercise the system and uncover any issues prior to launch so they might be remedied. Unlike Hubble, which orbits roughly 350 miles above the surface of Earth and was therefore accessible by the Space Shuttle, Webb will orbit the second Lagrange point (L2), which is roughly 1,000,000 miles from Earth. There is currently no servicing capability that can be used for missions orbiting L2, and therefore the Webb mission design does not rely upon a servicing option.

---

Design of a moon base would not fit in a single forum post:)

First step must be cheaper access to Earth orbit. Without it we cannot even start.

I don't believe separating metals from moon dust or making glass is very difficult. Those materials are needed to expand moon base. Same materials can be used to make heaviest parts of telescopes. We should build Moon base before attempting to go any farther.

When we have manned moon base, building and servicing moon telescopes becomes reasonable.

 

[jkn]

Cheap access to orbit? It's not access to orbit. It's manned presence in space that is expensive...thefails safe infrastructure to support a human. The fuel was less than one thousandth the cost of a Shuttle flight...the rest was making sure astronauts did not die.

Putting some crew on the Moon to install or service a telescope would cost tens of billions of dollars.

Expendable rockets are very expensive to use for an obvious reason. Shuttle was not better, because it needed half year service between flights and it was very complex machine. I guess they almost rebuild it every time. Currently fuel cost is insignificant. Life support system increases cost, because it increases mass. It is not terrible expensive itself.

If we manage to build a rocket which can be used like an airplane (return to launch site, quick service, refuel, fly again), then situation changes.

With current cost/kg to orbit, moon telescopes are not reasonable.

Situation can change.

Personnel on moon base will not be there only to service one telescope.

---

 

[Jon Richfield]

If we manage to build a rocket which can be used like an airplane (return to launch site, quick service, refuel, fly again), then situation changes.

With this I must sympathise,because I have long contemplated alternatives to rocket launches and am convinced that we could already be working on cheaper, more efficient, and safer options. I see very little sign of any initiatives of the type though.
But I don't know of any manned mission, especially long stints, in which the investment in getting the people up and down again was not greater than in getting the payload up (and possibly down of course).

Personnel on moon base will not be there only to service one telescope.

Yes, but no (semi?) permanent moon base, nor in fact a thoroughly temporary moon base, could possibly be justified by any number of telescopes. I have not yet seen any example of a rational argument for a permanent moon base, nor for moon mining. Even if someone tomorrow comes up with a means of burning 3He economically and competitively, mining 3He from the moon is one of the nuttiest ideas I have seen. If someone came up with a rational justification for a moon base, I would be right behind it, I assure you, but I am growing purple in the face holding my breath on that one. However, when such a proposal does materialise, it does not follow that it will justify casually raising a backyard crop of moon observatories on the side in between doing some honest work, nor guarantee that they will be any better to design, build, run, or service on the moon than in space.

Bottom line: I am ALL in favour of space projects but only if they are viable and functional. So far I have heard of none involving moon or Mars colonies. Other initiatives by the dozen, sure, maybe by the thousand for all I know, especially Mercury, Venus, asteroids, comets, Kuiper belt, Lagrange points and in various orbits and trajectories. But the moon? Tell me when and what. Observatories on the moon? Have a heart!

 

[Jon Richfield]

What possessed me? Knowledge. I was writing about JWST.

That sounds terribly final, but it happens to be beside the point. The folks are designing Webb to be unserviceable () all right, which is surely the wildest gamble in space history to date, and a gamble that is partway lost before starting because of the very costs you mention, but that is a design choice, not a necessary attribute of space telescopes, whether at the L2 point or anywhere else. It is an accident of history, part of the long-term consequences of a space programme that started out as a geopolitical exercise in national aggrandisation, and humiliatingly has continued on the same line ever since.
In a rational history there would long ago have been plenty of sustainable infrastructure for shuttling maintenance missions to as many space observatories as we would have liked, but as things stand it is mainly the commercial craft that make the running, and they aren't wasting their time with that sort of thing.
The real straw in the wind is the Chinese initiative and the political deterioration in relationships with Russia. I'd say that the US prospects just now are the most threatening since 1861.
But if they really need to service the Webb, they not only could, but could do it more easily (wellll, let's say with less difficulty and danger) than an installation on the moon, and very likely might, if Webb pulls a Hubble on them, or even a Philae. The limiting factors would be the will and the design of the craft, not the accessibility of the station.
Note the wording: "There is currently no servicing capability that can be used for missions orbiting L2, and therefore the Webb mission design does not rely upon a servicing option."
So much for unserviceability of craft in space.

Design of a moon base would not fit in a single forum post:

Tell me about it!

First step must be cheaper access to Earth orbit. Without it we cannot even start.

I fully agree. Read what I said above "...accident of history, part of the long-term consequences of a space programme..."
What are folks likely to do about it? Our greatest hope here is that the Chinese initiative will stimulate Western space developments, but frankly...
Any bets on our finally having to go cap in hand to the Chinese to buy their space products on their terms?
They have the money and the pride and the initiative and the lack of commitment to a past history of development in space such as that which hobbles Western ideas to pedestrian designs, pork barrels and boondoggles.
If this were a horse race, where would your money be?

I don't believe separating metals from moon dust or making glass is very difficult. Those materials are needed to expand moon base. Same materials can be used to make heaviest parts of telescopes. We should build Moon base before attempting to go any farther.

Tell me ALLLLL about that when you have shown us how easy it is to do such things. You don't have to go to the moon for a first try just to convince me, just build yourself a few solar furnaces to produce the sorts of parts you would need for the colony buildings (never mind the telescope).
When you have accomplished that satisfactorily, tell us about how you would manage the precision parts. (Did you imagine that airlock doors for hard vacuum could be made from moondust clinker?)
Then tell us how you would get those plentiful metals out of the moondust in a usable form and what you would do about prospecting for the lunar ore deposits, or did you think that just any old dust would do?
You might find it sobering to get yourself a guided tour to some Earth-based ore processing plants for extracting metals, and foundries for processing them.
Then extrapolate the costs of getting and designing the functionally and appropriately equivalent functions on the moon.

When we have manned moon base, building and servicing moon telescopes becomes reasonable.

Right. So will our first bulk delivery of lunar green cheese. On current showing I wouldn't bet on anything of the kind this century.
And I am not sure of a lunar observatory the following century.
Meanwhile we have some astronomy to do, including some very important and urgent astronomy. And other space functions.
None of which needs a moon or Mars colony.
Think about it...

 

[mfb]

I don't believe separating metals from moon dust or making glass is very difficult. Those materials are needed to expand moon base. Same materials can be used to make heaviest parts of telescopes. We should build Moon base before attempting to go any farther.

If it would be easy, raw materials on Earth would be cheaper. Compared to Moon we have way better options to build separation-factories, but rare materials are still very expensive. If you calculate the net work of an average cubic kilometer of earth, you get something like billions of dollars. So why does it cost nothing to buy a cubic kilometer of Earth in the middle of a desert? Well, processing this costs much more than a billion.

If we manage to build a rocket which can be used like an airplane (return to launch site, quick service, refuel, fly again), then situation changes.

SpaceX will try it again (with the first stage) tomorrow, and they plan to re-use the second stage in the future, too. That can be game-changing (unfortunately, it would also give them a quasi-monopoly).

Edit: wrong word.

 

[jkn]

Tell me ALLLLL about that when you have shown us how easy it is to do such things.

Why should I explain how we separete metals from ore? We both know we can do it. We have produced metals thousands of years (at least gold, silver, copper, tin, iron and lead). So that is not enormously difficult.From picture in Wikipedia article 'Regolith':
Lunar 'soil' = regolith with grain size 1 cm or less:
12% iron
7 % aluminum
6 % magnesium

Do you really claim that we cannot design machinery to separate those?

Collecting this 'soil' could be done with small remote controlled (from Earth) machinery.

Manufacturing complex parts is not that hard. 3D printed parts for rocket engines are tested. Jet engine made completely from 3D printed parts has been tested.

From regolith we also get some He3 and lot of O2.Strongest reason why we need to build permanently manned moon base:
If we are ever going to build manned station anywhere farther away, we need first to build moon base.

1: Escape from Moon base to Earth takes couple days. From anywhere else couple years or more.

2: One problem Biosphere 2 had was too heavy work load for inhabitants. Work load in Moon base can be reduced by remote controlled equipment.We have three possible futures:

A: Never expand to space. Stay on Earth until some natural or man made disaster kill us all.

B: Build Moon base and use technology tested there to build bases elsewhere.

C: Ignore Moon and go directly to asteroids or elsewhere.C is slower and more expensive than B, because:
- Help is years away instead of days. So everything must be more reliable. That costs and increases development time.
- Remote controlled, by Earth, tools are not available. So more automation is needed making technology more complex. Complex tech that certainly works without complete testing...

Risks and costs are reduced by taking shorter steps. If we take too long step and fail, we will waste decades before trying again.Instead of Space Shuttle we should have made first stage of Saturn V reusable.

 

[russ_watters]

A: Never expand to space. Stay on Earth until some natural or man made disaster kill us all.

That isn't a real need and even if it was, there isn't anywhere else in the solar system that can support anything but a tiny fraction of Earth's population.

While it would be cool to have a moon base and the spirit of exploration is cool, there is no chance of that being reason enough for people to be willing to spend trillions of dollars on something that has little tangeable value.

 

[atyy]

SpaceX will try it again (with the first stage) tomorrow, and they plan to re-use the second stage in the future, too. That can be game-changing (unfortunately, it would also give them a quasi-monopole).

What, what? Before the LHC?

 

[mfb]

Why should I explain how we separete metals from ore? We both know we can do it. We have produced metals thousands of years (at least gold, silver, copper, tin, iron and lead). So that is not enormously difficult.

If it would be easy, where is the autonomous machine on Earth that can extract metals (anything) out of rock? In particular, without a constant supply of chemicals from elsewhere?

2: One problem Biosphere 2 had was too heavy work load for inhabitants. Work load in Moon base can be reduced by remote controlled equipment.

Why was that not an option for Biosphere 2? Everything that works on the moon is so much easier here on Earth.

What, what? Before the LHC?

Thanks, I forgot that English uses two different words (both are "Monopol" in German).

 

[Jon Richfield]

Why should I explain how we separete metals from ore? We both know we can do it. We have produced metals thousands of years (at least gold, silver, copper, tin, iron and lead). So that is not enormously difficult.

Not enormously difficult?
I should LOVE to be a fly on the wall if you were to explain that to say, a geologist, a miner, a metallurgist or an industrial chemist.

Lunar 'soil' = regolith with grain size 1 cm or less:
12% iron
7 % aluminum
6 % magnesium
Do you really claim that we cannot design machinery to separate those?
Collecting this 'soil' could be done with small remote controlled (from Earth) machinery.

You appear to think that that means that if we send a machine with Earth comms and controls to the moon, then all we need is to look at our control screen while it picks up 100 pebbles, takes out the ten iron ones, the 7 Al ones and the 6 Mg ones, and discards the unwanted 75 pellets of oxygen, Si and so on?
I think you really, really need to find out what metal separation entails, even on Earth, and how it would differ from metal separation on the moon. If you did you would not have said anything as fatuous as "Why should I explain how we separate metals from ore".
The short answer is that it is easier said than done. Come back and tell us all about it when you have found out why it is not so easily done.

Manufacturing complex parts is not that hard. 3D printed parts for rocket engines are tested. Jet engine made completely from 3D printed parts has been tested.

Before quoting journalists' headlines on technical matters so glibly, you should read and understand the content as well. If you had done so you wouldn't have revealed your undone homework so vividly.

From regolith we also get some He3 and lot of O2.

To be precise, you do not get any O2 from regolith at all. You get a lot of chemically stable oxides. Until you can explain why that makes a difference, forgive me if I ignore your views on the point. That isn't even industrial chem 101; it is lower high school concept material.
Do tell us how you see our machine collecting the He3 pellets and storing them. And what do we or our little moon robot want it for? If someone suddenly gave us a gift of a few million tonnes of He3 down on Earth today, suitably packaged, how grateful should we be? We could eagerly use a few hundred kg maybe, but for the foreseeable future, it would amount to a major parking bill. We simply do not yet have a use for anything of the type. Least of all on the moon.Unless you can suggest a use for some really nice balloons on the moon, of course.

Strongest reason why we need to build permanently manned moon base:
If we are ever going to build manned station anywhere farther away, we need first to build moon base.

Nonsense. In the light of present knowledge, it would be nutty to go elsewhere via a moon base in the next century or so.

1: Escape from Moon base to Earth takes couple days. From anywhere else couple years or more.

This is a joke, riiight?

2: One problem Biosphere 2 had was too heavy work load for inhabitants. Work load in Moon base can be reduced by remote controlled equipment.

Get real mate! If that were true, why couldn't we use remote controlled equipment in Biosphere 2? Or even locally controlled? Once again you show a need to do some homework and find out why B2 didn't work and why we had better find out what to do about it before making fools of ourselves killing our space pioneers.

A: Never expand to space. Stay on Earth until some natural or man made disaster kill us all.

Here for a change I agree. In fact I predict that is the future for Homo sapiens and possibly even for life on Earth. As I am getting tired of saying (not to you in particular) the reason that will happen is that we are apes and not termites.

B: Build Moon base and use technology tested there to build bases elsewhere.

A little of that might happen, but the moon being a sterile objective, much like Mars, we would be fools to waste too much time on it, and unless our technology changes radically, we would be even bigger fools to waste more than we can avoid on anything resembling permanent bases there.

C: Ignore Moon and go directly to asteroids or elsewhere.

This one has merit because it can be preceded by exploratory investigations that could reveal whether any of the bodies in question had anything to recommend it. And a lot of valuable work could be done in the process. After that we could get down to serious projects.

C is slower and more expensive than B, because:
- Help is years away instead of days. So everything must be more reliable. That costs and increases development time.
- Remote controlled, by Earth, tools are not available. So more automation is needed making technology more complex. Complex tech that certainly works without complete testing...
Risks and costs are reduced by taking shorter steps. If we take too long step and fail, we will waste decades before trying again.

For a start, forget help from Earth until we are in a position simply to lift off with adequate resources at a day's notice.
Which I assure you, we are not, and not likely to be in soon. And if we were it would double the cost of the project or worse to run it like that, and only in a minority of disaster cases would it be worth the trouble. You can do a lot of dying in space in a few days you know! And in many other cases you could arrive at the scene of the fun and spend your friends' last hours waving at each other through the portholes and chatting about the good old days till they die, because the accident had rendered his 3D printer unable to print a new airlock in time, or because you could not fit your airlock into the space under the rockfall blocking the way out. (Pick your choice of disasters and compare with accidents to submarines or in caves, or deserts or...)
Get the picture?
In this connection it definitely would be cheaper to be reliable than to have backups. Ask the Hubble engineers.
Shorter steps?
Certainly shorter steps are an attractive idea when boldly going where none have gone.
After all, why build a bridge, wildly expensive and dreadfully vulnerable, when instead you could try to cross the chasm in two short jumps instead of risking all on a single initiative?
In a project like space or on the moon you do not approach it by saying "Oh mommy! If I get into trouble I do hope you will and get me out of it like you always do."

Instead of Space Shuttle we should have made first stage of Saturn V reusable.

Do tell, do tell! Silly of all those dumb rocket engineers. Fortunately they didn't have a lot of politicos to queer the pitch for them... <siiiiigh!>

 

[jkn]

That isn't a real need and even if it was, there isn't anywhere else in the solar system that can support anything but a tiny fraction of Earth's population.

While it would be cool to have a moon base and the spirit of exploration is cool, there is no chance of that being reason enough for people to be willing to spend trillions of dollars on something that has little tangeable value.

About money I agree. But this solar system has resources for much larger population than Earth has now. Need to go there is not immediate.

If it would be easy, where is the autonomous machine on Earth that can extract metals (anything) out of rock? In particular, without a constant supply of chemicals from elsewhere?Why was that not an option for Biosphere 2? Everything that works on the moon is so much easier here on Earth.

Automation is needed on asteroid station. On moon station remote control from Earth is enough. This is one reason why we should practice with Moon station first. All chemicals can be recycled.
I don't have time to comment everything you write. I'm trying to keep my English at least readable. So I concentrate to one point:

I wrote:
1: Escape from Moon base to Earth takes couple days. From anywhere else couple years or more.

This is a joke, riiight?

I believe you agree that we can get from Moon to Earth in couple days. So how can escape time from Mars or asteroids be shorter than 2 years? That 2 years includes necessary wait for launch window. You cannot do it faster with current engines. From Venus time might be shorter, but that is last place to go. Manned mission to Mercury is not possible with current engines.

 

[rootone]

Any base on the Moon is going to need a power supply, industrial plants on the moon will need a BIG power supply.
Conclusion - Before doing anything else we would need to either install a nuclear power station or else substantially cover the surface with solar power collectors.

 

[mfb]

Automation is needed on asteroid station. On moon station remote control from Earth is enough. This is one reason why we should practice with Moon station first. All chemicals can be recycled.

Please give a reference for claims like this, otherwise the discussion has to end here. Unsourced speculation is against the forum rules, and you make a lot of claims without citing any sources. That is not how this forum works.

 

[Jon Richfield]

About money I agree. But this solar system has resources for much larger population than Earth has now. Need to go there is not immediate.

Non sequitur and the unspoken premises are debatable if even that were logical.
Besides, there is NO WAY we could solve our population problem by emigration even if an alien super-race were to park a dozen planet Earths within easy rocket reach. Do the arithmetic. I know of one planet that could take and support our present population indefinitely, but for lack of any super-species to get us there in a condition to survive means that it would take a few thousand years to do the terraforming, by which time, at a doubling time of say 30-50 years, our population would outweigh the planet. But at our present rate we would need to export about a third of a million people a day just to stay at our current level of overpopulation.
And that is without reckoning in what it would take to establish them viably.

Forget emigration! The only incentive for off-planet colonisation is survival and dissemination of the species, not of the huddled masses; those will always be with us until they all perish.

Automation is needed on asteroid station. On moon station remote control from Earth is enough. This is one reason why we should practice with Moon station first. All chemicals can be recycled.

Remote control with a transmission delay of over a second each way would only be practical for a few types of tasks, and you can't practise automation by playing with remote control anyway. A bit deeper thinking please!

1: Escape from Moon base to Earth takes couple days. From anywhere else couple years or more.
I believe you agree that we can get from Moon to Earth in couple days. So how can escape time from Mars or asteroids be shorter than 2 years? That 2 years includes necessary wait for launch window. You cannot do it faster with current engines. From Venus time might be shorter, but that is last place to go. Manned mission to Mercury is not possible with current engines.

Never mind other-planet rescue; think of just our backyard moon colony or whatever it might be. "Hey Mabel! Seems those guys in Tranquillitatis construction site got themselves into a mess. When is the next launch window? Thursday? Got a craft ready? Oh well, when then? No, not that one, it can't accommodate all of them. Hey you guys up there, how long can you hold out? Two days? Oh well never mind then..."

 

[mfb]

Never mind other-planet rescue; think of just our backyard moon colony or whatever it might be. "Hey Mabel! Seems those guys in Tranquillitatis construction site got themselves into a mess. When is the next launch window? Thursday? Got a craft ready? Oh well, when then? No, not that one, it can't accommodate all of them. Hey you guys up there, how long can you hold out? Two days? Oh well never mind then..."

You don't need launch windows on moon. Keep a spacecraft ready that has supplies for a few days for the crew. It can go to moon orbit at any time, go from there to a transfer orbit, enter the atmosphere of Earth within three days and land. One day more in moon orbit allows to choose from a large range of landing spots if necessary. The ISS has a similar system with the Soyuz that stay attached to it.
Transporting astronauts to the escape vehicle can be tricky, but that is independent of the object you are considering. The time to get home is significantly shorter from moon.

 

[Jon Richfield]

You don't need launch windows on moon. Keep a spacecraft ready that has supplies for a few days for the crew. It can go to moon orbit at any time, go from there to a transfer orbit, enter the atmosphere of Earth within three days and land. One day more in moon orbit allows to choose from a large range of landing spots if necessary. The ISS has a similar system with the Soyuz that stay attached to it.
Transporting astronauts to the escape vehicle can be tricky, but that is independent of the object you are considering. The time to get home is significantly shorter from moon.

You seem to have a very simplistic view of moon launchings and the sort of preparations you need for rescues that you haven't even bothered to characterise yet. We don't even succeed with mine, earthquake, flood, cave, and submarine rescues on Earth, and you seem to think that lunar rescues are just taxi jaunts? And that three days would suffice for unscheduled rescues, and that that would be fast enough even if we could manage it?
Tell me allll about it once you can instance the points of correspondence with and discrepancy from the ISS. Which discrepancies, I might add, are part of the reason why telescopes in orbit, and even colonies in orbit would make more sense than on the moon.
I hope to goodness that whoever plans our space future takes the whole matter of technicalities and objectives a LOT more seriously than you do.

 

[mfb]

and you seem to think that lunar rescues are just taxi jaunts?

No I don't think so. But you can make the necessary preparations. And you probably want that unless the moon base is so large that a quick rescue won't be feasible (or necessary).
On Earth, you don't have a fueled rocket sitting next to everyone to use in case of emergencies.

and that that would be fast enough even if we could manage it?

That was never part of the discussion.

are part of the reason why telescopes in orbit, and even colonies in orbit would make more sense than on the moon.

I fully agree with you on those points, and I don't see the relevance of them for the discussion how long it would take to reach Earth from moon.

I hope to goodness that whoever plans our space future takes the whole matter of technicalities and objectives a LOT more seriously than you do.

There is no need to get personal.

Can you explain where the launch windows would come from?

 

[davenn]

SpaceX will try it again (with the first stage) tomorrow, and they plan to re-use the second stage in the future, too.

that, unfortunately became a dismal failure, exploded a couple of minutes after launch

Dave

 

[Jon Richfield]

that, unfortunately became a dismal failure, exploded a couple of minutes after launch

Dave

Yes. I was not in any way involved,except for being on the same planet more or less, but it still was so painful that I am thinking about other stuff.

 

[Chronos]

The recent launch failure of the ISS resupply mission merely reaffirms our technological ineptitude. God forbid we should ever be compelled to launch multitudes of nuclear missiles to divert a wandering space rock.

 

[Jon Richfield]

The recent launch failure of the ISS resupply mission merely reaffirms our technological ineptitude. God forbid we should ever be compelled to launch multitudes of nuclear missiles to divert a wandering space rock.

Though I am compelled to admit the persuasiveness of your point in the light of that event, we need to see this as a statement on our current status and our need to advance, not necessarily a condemnation of our future prospects in space.
It is not a fundamental principle of our necessarily continuing incompetence. We can and must continue to advance until we can profitably and reliably launch what we need to, on the schedules that we face and safely and reliably.

 

[Chronos]

Agreed. We are not as space competent as we may believe or should be. That is enough reason to not relinquish our dreams of things like space stations or moon bases. Our very survivable will someday depend on out ability to do such things reliably and economically. My issue is in getting out there, we can figure out the economics later. I suspect medieval european royalty had similar concerns about exploring the new world.

 

[mheslep]

Let me add another point- the moon keeps one face pretty much toward the earth. If we put a telescope on the moon on this side, most of the "visible sky" would be the earth. If we put it on the other side, we would have major problems with communicating with it, getting its images and controlling it.

Old thread, but there must be some other objection to a solution via relay satellite in lunar orbit (~2 hour period), or http://www.labspaces.net/pictures/blog/4cd8b1c15732e1289269697_blog.jpg? Forty posts in and I've not seen the objection yet.

 

[SteamKing]

Old thread, but there must be some other objection to a solution via relay satellite in lunar orbit (~2 hour period), or http://www.labspaces.net/pictures/blog/4cd8b1c15732e1289269697_blog.jpg? Forty posts in and I've not seen the objection yet.

If you had infinite funds to spend on a telescope, sure, put a dozen of them of the Dark Side of the Moon and launch a bunch of relay satellites. But, since you have only limited funds, the question must be asked: what would you see thru a telescope from the DS of the Moon that you wouldn't be able to see thru a telescope in Earth orbit? The telescope in Earth orbit is easier to maintain, since you don't have to send the Maytag repairman to the Moon every time something breaks down.

A billion here, a billion there, and pretty soon, you're talking real money.