The Moon’s surface is kind of a pain to work with. Gazillions of years of micrometeorite hits and solar radiation has ground the rocks on the lunar surface into dust called regolith, and it’s several centimeters thick. It gets into everything, clogging up machinery, and may even be hazardous to human health if it gets breathed in (it mixes with fluids and turns basically into concrete).
But that very characteristic might actually be useful. Peter Chen, an astronomer at Goddard Space Flight Center, wants to use it to make telescopes on the Moon!
He used a simulated lunar regolith to create a concrete-like substance that’s very hard and thermally resistant to flexure (it doesn’t change its shape when you heat and cool it). It has a ton of potential uses… like, oh, say, if you coat it with something reflective it would make a pretty decent telescope mirror.
This is a fantastic idea. If we’re going to live on the Moon anyway, then using the materials that are already there helps a lot. Lifting a big mirror to the Moon would cost a fortune, but using the regolith that’s just sitting there saves a huge amount of time, effort, and of course money. The idea to use in situ materials has been around a long time, but Chen’s new material may be a firm step in actually being able to implement this.
Imagine! In the lower gravity, much larger telescopes can be built. It wouldn’t be easy — in fact, it would be a considerable pain — to manufacture a 50 meter optical telescope on the Moon. For comparison, the biggest telescope with a mirror on Earth is (are?) the twin ten-meter Keck ’scopes in Hawaii. But still, being able to scoop up dust on the Moon to create the mirror (and probably other parts as well like the foundation and structure) for a telescope like that would make it a far sight easier.
In fact, if you want to think really big, why not coat an entire crater? They’re close to the right shape to start with… and you could wind up with a telescope hundreds of meters across!
And once we’re there to stay, a project like that would, literally, be dirt cheap.
June 4th, 2008 at 11:16 am
If one did coat an entire crater to create a lens, how would we readily reposition the scope to see what we want?
June 4th, 2008 at 11:22 am
I just have two questions
1) where to get liquid on the moon?
2) how to cope with the remaining regolith? it will hell well cover whatever you build. And optics is not something you want to be covered with a few cantimeters of dust.
June 4th, 2008 at 11:33 am
Isn’t the constant hits by stuff that would burn up in Earth’s atmosphere an issue for anything built on the moon?
June 4th, 2008 at 11:34 am
Andy, I guess we’d drag our own liquid. Can’t take that much to make this really….
And the dust… It’s not as if there’s wind on the moon so I doubt that’d be a massive problem. The humans just have to be really really careful around the thing to not move too much dust.
June 4th, 2008 at 11:47 am
Well, if there is ice at the lunar poles, that would be the source of the moisture… or perhaps we could divert a comet to impact near the construction site. Certainly the expense of lofting water to the moon would be cost prohibative.
I would think the dust would only be a problem when such a ’scope was under construction. Once the dust settles, unless we kick it up again, it would take a very, very long time for an appriciable layer to build up on a mirror surface.
As for micro-meteoriod impacts…
They will happen. The question is, would they really matter? If the mirror were designed to take the impacts with minimal damage (leaving a neat hole, instead of torn, bent area around it) couldn’t a lunar ’scope the size we’re discussing here simply ignore the damage? Seems to me the imaging system software could be engineered in a way to “ignore” the damaged areas, and fill in the missing image components with a slightly offset observation. After all, how often do you notice your retinas’ blind spots? Sure, eventually a panel might become so damaged to need replacing… but again, this seems to be a problem of design, rather than physical impracticality.
June 4th, 2008 at 11:55 am
to get a smooth mirrored surface any mirror would need to be planed, usually this is done with a liquid of some sort to prevent scratches. Dust comtamination would be an issue too, just from people or machines stirring up the dirt. I’d have to agree that building optics of any quality would be challenging. It would be cool to see it done though.
@Andy / Michelle, I’d agree getting water there is the biggest challenge.
Maybe building something practical like a telepscope would be a good first step.
June 4th, 2008 at 11:58 am
So much for getting Ikea to sponsor and manufacture flatpack telescopes to ship up there …
I guess they could still make a DIY radio telescope instead. Would it be possible to a park of those on the moon in concert with ones here on earth to get a baseline the size of the Moon’s orbit insted of ‘just’ the Earth’s diameter as is the case now?
If we can indeed put a 100+ m telescope in a crater (which would be awesome, what do we do when the sun shines on it? Hoist up a steam turbine instead the CCDs?
June 4th, 2008 at 12:02 pm
@ Andy:
AFAIU they suspect there is water on the moon. Sputtering from the solar wind (hydrogen) releases atoms (oxygen) from ore and so you have water, possibly condensing on surfaces where the sun never shines (craters at the poles). Other speculates in water from cometary material.
IIRC there could be large amounts according to some instruments mapping the Moon.
@ Michelle:
AFAIU electrostatic levitation and later settling of dust is possible, from the solar wind. But that also suggests methods of preventing it.
(Actually, some would like to try scifi looking EM “shields” to decrease radiation problems for, em, “mooners”; relatively small mass and cheap energy in the sun. Maybe they would serve double use.)
June 4th, 2008 at 12:03 pm
You need liquid on the moon to make a telescope? If you want, you can spin cast a telescope there – just heat up some dirt.
You can protect the mirror from meteor strikes by building a tube, like the HST.
Radio astronomy on the moon should be easier. The tolerances to dish shape are much easier. The lunar far side is radio quiet from Earth noise. That’s where i’d start lunar astronomy.
The Keck is a multiple mirror 10 meter telescope. The SALT is an 11 meter single mirror scope. I’m not saying that the SALT is better, just bigger. The cheap mount design of the SALT means that less than 10 meters is actually used, at least most of the time. I don’t know all the details.
http://www.salt.ac.za/telescope/overview/
June 4th, 2008 at 12:08 pm
Sili, for such reasons I would think they will do radio telescopes first. It will also be a nice radio shadow from Earth, and in principle they only need to throw or lay some isolated wires radiating out from a central point to lie on the ground. Cheaper too.
June 4th, 2008 at 12:12 pm
Stephen, do we really need a dish for a radio scope? Can’t we use the phase information as for modern radars, to make a flat and non-moving design?
June 4th, 2008 at 12:34 pm
I always liked the idea of radio astronomy done from the far side of the moon. With the bulk of the moon to block terestrial noise you could get the kind of “dark” skies that have not been avaiable for a century down here.
June 4th, 2008 at 12:35 pm
Oops, cant even type my own screen name…
June 4th, 2008 at 12:39 pm
If gravity is an issue for size, then make a telescope on a moon of some gas giant- or even Pluto, or other Kuiper Belt object. Water ice weighs less than regolith concrete, and at that distance is as hard as rock. Takes a nicer polish too, I would imagine. For that matter (lit/fig) why not just make a water mirror a couple of hundred miles across in zero-G far enough from the Sun to prevent evaporation.
June 4th, 2008 at 12:40 pm
Well, yes, but that’s a mighty big “if” there. We’ve got the technical know-how, sure, but is a permanent lunar colony realistic in the foreseeable future? It would be phenomenally expensive, and with the economy slowing down, I’m not sure “scientific advancement” would be enough of a payoff to make it a politically viable project.
June 4th, 2008 at 1:05 pm
What kind of manpower would the 50m mirror you’re proposing require to construct? I feel like it would be tough to get enough people there to do the job.
June 4th, 2008 at 1:06 pm
IIrc, doesn’t the moon tend to get a layer of dust floating around up to about twenty feet when the sun shines and ionizes particles?
June 4th, 2008 at 1:23 pm
IMHO, this is the problem with NASA: before they try to figure out how to build a telescope on the moon maybe they should build the infrastructure to, I dunno, enable us to actually GO THERE, then figure out how to sustain a permanent presence there without constant support from Earth.
The image with the post made me laugh: it’s just like the ones in those books about space in grade school in the 1970s. And it’s still total fantasy.
June 4th, 2008 at 1:36 pm
I have to agree with Ian.
I actually get annoyed now when I see pretty artwork because throughout my life (41+ years) most interesting proposals for manned spaceflight have remained just that – artwork.
I’m not criticizing the artist – I couldn’t possibly even begin to create a picture like that. But to achieve that kind of thing in reality? 30+ years I reckon _with_ funding which probably won’t happen.
June 4th, 2008 at 1:41 pm
Perhaps similar materials could be used for construction of other structures.
I am curious about the ratio of lunar rock to nanotubes and to epoxies.
June 4th, 2008 at 3:01 pm
For aesthetic and paranoiac reasons, I have absolutely no doubt that if it were ever built, it would have to be done on the far side of the Moon. (I almost said the “dark side”.)
June 4th, 2008 at 4:40 pm
I can only imagine what an optical ’scope hundreds of meters across can resolve.
Anyone have any estimates?
June 4th, 2008 at 4:53 pm
It’d be fine right up until a full moon when your giant mirror burns a path across our entire planet.
Admit it. That was your plan all along.
June 4th, 2008 at 4:56 pm
“IMHO, this is the problem with NASA: before they try to figure out how to build a telescope on the moon maybe they should build the infrastructure to, I dunno, enable us to actually GO THERE, then figure out how to sustain a permanent presence there without constant support from Earth.”
So you’re saying get to the moon first and come up with reasons why later? Build a base THEN see if it’s conceivable to put a giant mirror up there?
Good thing you’re not running NASA eh?
June 4th, 2008 at 4:57 pm
“where to get liquid on the moon?”
I have just one new word for you: urinecrete. They just have to stop drinking so much of it.
June 4th, 2008 at 6:23 pm
“I actually get annoyed now when I see pretty artwork because throughout my life (41+ years) most interesting proposals for manned spaceflight have remained just that – artwork.”
Artwork like that is necessary though, it gets people interested and willing to fund something as cool as moon bases, rocket ships, robots, probes, all kinds of cool techno gadgetry. Laughing at old artwork next to modern pictures helped me get through school, and I hope our kids kids get to laugh just the same.
June 4th, 2008 at 6:48 pm
The pretty artwork and ideas are essential. Many people don’t have much imagination when it comes to space exploration. Anything that helps people visualise the possibilities is important.
You can build all the infrastructure you want but what does it get you? You build infrastructure to support things like the telescope. To get funding you need a reason to go. So more big ideas please.
June 4th, 2008 at 7:13 pm
How poetic would it be to turn the Kepler crater into a giant telescope? Weee!
June 4th, 2008 at 7:43 pm
shane said:
“The pretty artwork and ideas are essential. Many people don’t have much imagination when it comes to space exploration. Anything that helps people visualise the possibilities is important.”
Hear, hear, shane. It’s all part of the process.
To establish a permanent human presence in space will of course take sustained political support; that’s the nature of the game we have to play. Right now I don’t see that happening in the U.S. The Chinese have voiced ambitious plans for space exploration, though their own aerospace infrastructure will have to overcome significant hurdles.
Private enterprise, particularly in the U.S., may be able to rally public interest in manned space development. If companies like Virgin Galactic can succeed in “space tourism” on a regular basis, competition in the private sector might succeed where the political will falters.
Yeah, yeah; pretty big ifs and mays, no argument. A very long way from the pretty pictures to turning an entire Lunar Farside crater into a giant radio / optical scope. But we have to start somewhere.
June 4th, 2008 at 8:55 pm
There have been ideas of liquide telescope on the Moon where the liquide is mercury:
http://www.sciencedaily.com/releases/2007/06/070620154940.htm
So you can actually bring your telescope to the Moon in a bottle. It is over 10 to 20 time less expensive then conventional mirror. All you do is spin the mercury around to get your telescope.
The downside of it is your telescope is always pointing at the zenith…
If I remember well, last talk I talk to him (E. Borra) he was adding iron in the mercury and move it sideways ~10 degrees with magnetic field.
June 4th, 2008 at 9:27 pm
In related news: There are already proposals for using the moon as a detector for cosmic neutrinos at very high energy, such as GRB or AGN neutrinos. The idea is to have a satellite around the moon that detects radio pulses from neutrinos hitting the moon’s surface.
June 5th, 2008 at 6:03 am
Just send me up there with my trusty feather duster a pair of rubber gloves and a vacuum cleaner and I’ll have the moon all clean and shining in a twinkling! : )
June 5th, 2008 at 6:46 am
Awesome idea – & nice tagline there BA
I love the thought of doing this …
June 5th, 2008 at 6:52 am
… & I can’t resist putting this togtherfromtwo earlier posts :
&
Yes, Keith you go weee! to produce the urinecrete to cover Kepler crater …
Now I know there’s a lunar Alps & Appennines & so forth but is there a lunar equivalent of the yellow river? Or will there be?
June 5th, 2008 at 7:14 am
Richard Wolford said:
“If one did coat an entire crater to create a lens, how would we readily reposition the scope to see what we want?”
‘Readily’ requires some thought, but some pointing would be accomplished the same way Arecibo does it: by moving the receiver (or secondary mirror).
To everyone:
The artwork is nice, but would the floodlights look diffuse like that? That that was an atmospheric effect…
June 5th, 2008 at 7:20 am
Torbjörn Larsson, OM on 04 Jun 2008 at 12:02 pm
That’d be good. I’ve heard a few possible names suggested by Sf authors for further Lunar residents – Lunatics being one & Selenites perhaps a better alternative!
@ # shane on 04 Jun 2008 at 6:48 pm :
Agreed. Personally, I love the space-art even if only for its own sake. But when its inspirational and helps us picture a better future too – better yet!
&
Reasons to go?
Because its there mate!
Quite seriously, its part of being human I think .. we do have an innate need to explore further, to learn further – and its a good thing that will have hepas of spin-offs and advantages for us at the most fundamental level. There’ll be lots of spin-off’s cultural and artistic and social as wellas technological, they’ll be lots we can learn from doing this and .. well, heck, read some Carl Sagan, (’Pale Blue Dot’ for one is superb) he explains it better than I could & he’s spot on.
(& puh-leese folks, don’t use the stale old canards about “isn’t that money better spent on Earth solving our problems here?” That won’t happen. If the $ isn’t spent on space exploration then it’ll just be spent on needless wars & politician’s salaries & stupid junk like that. Besides no amount of money can by itself alone stop poverty, environmental woes, ad nauseam anyhow.
)
Plus too because if we don’t then the Chinese or somebody else – who will
probably hate America (as much of the planet does) – will do so and colonise the Moon with their people & their militaries & will use that “high ground” advantage over us in ways we are sure NOT to like.
We’ve got to go there or we’ll suffer badly in the future and regret it for centuries to come. The sooner our leaders realise this & get a
properly directed, properly funded, properly diven program in place to
get us there and beyond the better.
I honestly do think Apollo was the greatest thing the USA has ever done in all of history.
… & doing this could top it!
June 5th, 2008 at 7:39 am
Madge
Be careful what you ask for you may get it!
Pictures one lady astronaut wearing rubber gloves and holding a feather duster & a vacuum cleaner (would that even work on the Moon?) standing all alone on the vast, grey, cratered, empty, “magnificent desolation” landscape of the Moon …
Would hope you’ve got a lot of spare Oxygen tanks to tide you over on that job!
June 5th, 2008 at 7:47 am
# nih on 04 Jun 2008 at 4:53 pm
Somehow I don’t think that’d actually happen. The ’scope collects light not reflects it & I’m pretty sure it just wouldn’t work – you’d need to actually focus and aim the light like a gargantuan magnifying glass …
Mind you, (switches into evil genius mode) if you could do that and direct the beams then that’d certainly be one way of sorting out the Chinese competition & resolving (by solar fire) all the Middle East issues such as the Iraqi’s …
(Winking red emoticon with horns!)
June 5th, 2008 at 8:42 am
Wait a minute!
There may be some bad astronomy in that concept art. Look at the shadows: They’re all nice and shaded, like the light is being scattered through an atmosphere. They’re not knife-edged sharp.
Yes, that’s nit-picking. But decades ago I sketched a pencil moonscape from an Apollo photo, and couldn’t get the shadows right. I ended up using black ink to achieve that shadows in a vacuum effect.
June 5th, 2008 at 9:06 am
As far as water on the moon…..
A few days ago I was watching a documentary about the “new race to the moon” and there was a little blurb about a guy working out ways to use native lunar resources. He was working either at a NASA lab, or a lab contracting with NASA. He has worked out a method of extracting water from “simulated” lunar regolith. Of course the documentary didn’t give the details, but basically the process involved simply heating the regolith to a certain temp. (800 C ?). Anyway, it looks like there is a good chance that water is available most anywhere on the moon with the right equipment. How much, I have no idea. I Am interested in learning more about this process if anyone has heard of it.
June 5th, 2008 at 9:44 am
@Phil
Coating crater bottoms to produce a parabolic-shape is simply a ridiculous idea, if not impossible, as they ratio of crater depth to crater diameter is far off the required mark (we’re talking here about micro-metre-wave stastisitcs for, say, a 50-metre diameter telescope).
I think, however, that it would be wiser to look at this research as being applied to producing smaller diameter mirrors (say, a metre across), which could then be segmented together (like the SALT telescope setup in South Africa) to eventually produce the proposed 50-metre diameter (and upwards) mirror.
The machinery used for producing these 1-metre diameter-sized mirrors is quite a possiblility, and wouldn’t have to be huge in contrast to those used for producing the same sizes on Earth. And, as the moon’s gravity is 1/6 that of Earth’s, assembling them together (yes, inside craters) wouldn’t be at all to hard, I would guess.
John — http://www.moonposter.ie
June 5th, 2008 at 10:57 am
Vacuum evaporation.
But mercury suggested here would work because of extremely low evaporation rates, and I believe even oils (well, long polymer liquids) as they are used in vacuum equipment. Instead of making mercury magnetic you could make a much lighter oil-ferrous particle magnetic liquids, which can be shaped by fields to assume some shapes, some of which could fit a telescope mirror. And figuring out how to make them perfectly reflective, or possibly coat them with a thin mercury layer (assuming separation by non-solubility, but adhesion).
If they really work it, I think they could do some fantastic solar collector (sun side) – magnetic controlled telescope (shadow side) “sail” construction. But a reasonable moon telescope construction seems so much more achievable.
That was what I was thinking of. But is it speculation or verified?
June 5th, 2008 at 12:19 pm
Mercury would be nice, but it weighs a ton. Getting it there would be prohibitively expensive. … Google pause … …. density 13.56 g/cc; 1 cubic foot weighs 841 lb.
Regolith would also make a natural building material. Given enough time and effort, we could build 5,000-ft skyscrapers in that light gravity field. (Whether we’d want to is another matter.)
Making a big mirror is a great concept. I don’t know how spincasting would work out in that gravity, but if it could be done, you’d have a big mirror that you could tilt. Put it in a really big Dobsonian mount. You could use a bit of adaptive optics to account for the small deformation. Since the Moon spins a lot slower than the Earth, tracking would be less of a problem. You’d be able to make week-long continuous exposures. On the other hand, you’d only be able to see half the sky each month.
Water may be less of a problem than we think. (A mere 62 lb/ft^3). But one of the Arab states is building a city that they claim will recycle 99.99% of their water. They’d only need to bring in a liter 2 or 3 times a year to replace what gets lost by evaporation or carelessness. Search for Masdar City. Let’s wait and let them build their city, look at it for a decade or so (what’s the rush?), and see how the recycling works out.
June 5th, 2008 at 1:08 pm
[...] the post a few days ago about returning to the moon, and my desire to see a lunar observatory, this link seems apropos. It’s Phil Plait discussing Peter Chen’s idea for building things out of [...]
June 5th, 2008 at 2:34 pm
Good point. Seems some magnetic oils can have down to a few weight percent of magnetic particles, so density of oil could be in the range of automobile oils (or heavier oils). Googles … < 1 g/cm^3, compared to your 14.
OTOH regolith is completely free. Wasn’t there discussion of melting regolith, solar energy being plentiful? Could perhaps be the core of a spin cast mirror.
June 5th, 2008 at 2:49 pm
[...] Scoping Out the Moon Telescopes made out of Moon, coming soon to a store near you. [...]
June 5th, 2008 at 7:06 pm
can we make thousands of them, paint them with colored aluminum and then point them at the earth to make a moon sized “Jumbogiantorsaurustron ™”.
then sell ad space for a billions of dollars a day to pay for space exploration. Do you think coke or pepsi would pay $10,000,000,000 to advertise to a good portion of the world so easily?
Is this a bad idea? What if it was just one day a month? Should I be shot into the sun for mentioning this?
What would this do to those “uncontacted” tribes everyone made a big deal about recently?
June 5th, 2008 at 11:04 pm
Hi, I’m Todd from Regolithurinecrete Polishers, out of Fargo, wondering what’s the brew-ha-ha all about? Are you looking for an estimate?
June 6th, 2008 at 6:06 am
ZZMike on 05 Jun 2008 at 12:19 pm
Wouldn’t there be mercury (chem symbol : Hg) available on the Moon somewhere that we could mine it locally there & not need to bring it from Earth?
Or could we get Hg from asteroids passing by more easily than Earth?
Or alternatively, substitute another different but also reflective enough & more easily aquired / found / transportable mineral for the Hg instead?
June 6th, 2008 at 6:09 am
Hmm … Could we mine for mercury on mercury?
June 6th, 2008 at 6:16 am
travissimo :
YES!!!
Mess with their heads obviously!
Sure are – mates rates of course!
Just double the cost and we’ll split the surplus $ 50:50 just like any govt deal!
June 6th, 2008 at 8:38 am
Richard Wolford said: “If one did coat an entire crater to create a lens, how would we readily reposition the scope to see what we want?”
If we can make a telescope out of a crater on the moon, then we would just reposition the moon to point the ’scope where we want to look. Simple, really.