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NASA Has Plans for 2nd Space Station at L1

Keith Gabryelski writes "New Scientist has an article on NASA's unveiling of a "blueprint for the future" of space exploration. It entails a Space Station 5/6ths of the way to the moon. In other news, radiation sheilding on the space station isn't so good."

47 of 433 comments (clear)

  1. yeah but... by Anonymous Coward · · Score: 5, Funny

    radiation sheilding on the space station isn't so good.

    but my tan is great!

  2. Sure, THAT'LL happen by thetzar · · Score: 5, Interesting

    With the insane ammounts of cost overruns and mismanagement in the ISS project, who thinks that a jaded congress is going to vote a new space station [no matter how much MORE useful than the ISS it may be] any funds whatsoever?

  3. cant even afford current station by peter303 · · Score: 5, Interesting

    There is only room for three people for extended stays, due to Congressional budget cuts in the habitation module and escape vehicle. The original intention is seven people. That means the crew of three must spend 75% of their time in maintenance with only a small amount for experiments and other innovation. Unlikely the current administration will increase funding. Many republicans hate NASA because of its environmental monitoring programs. And the previous scientific leader of NASA has been replaced by an accountant (cut and slash).

    The new IMAX movie about the first three years of space station construction is fascinating.

    1. Re:cant even afford current station by shut_up_man · · Score: 5, Funny

      I agree about the Imax movie, it's excellent. Even Tom Cruise's hugely overdone voiceover doesn't ruin it: "And the VIEW HERE is... AWESOME. Just... AWESOME. No really, it's TOTALLY... AWESOME." Kinda like a cross between Keanu Reeves and William Shatner, with liberal snorts of cocaine.

  4. Plan ahead. by Anonymous Coward · · Score: 5, Funny

    "If you sent two people to Mars, one of them would die," says Marco Durante of the Federico II University in Naples

    I think the key to preventing this is to pack enough food that the astronauts are not forced to resort to cannabalism.

    1. Re:Plan ahead. by muertos · · Score: 5, Funny

      Or send somebody else instead of the guy who'll die.

    2. Re:Plan ahead. by Nordberg · · Score: 4, Funny

      Solution: Only send one guy.

      Madhouse: Satirized for your protection.

      --
      *Splort*
  5. Mixed emotions... by Orne · · Score: 5, Insightful

    The explorer part of me is saying, "Yay! It's about time we started building more structures in space. The Lagrange point would make a good neutral spot halfway to the moon." But then the realist in me says, "Given that NASA has proven that it can't stick to a budget, how much is this overrun going to cost?" And the article agrees with me.

    Government is not the answer to promoting outer space as a new resource -- market forces have shown to be the driving force in all new ventures. We need competition in getting things into orbit, tourism to build hotels, industry to build fab plants, mining on the moon...

    1. Re:Mixed emotions... by Daniel+Dvorkin · · Score: 5, Insightful
      market forces have shown to be the driving force in all new ventures
      [sigh] I am getting really sick of hearing this bit of ideology repeated as though it were an established fact. Some things happen as a result of market forces, some as a result of government forces, and some (actually most) as a result of the combination of the two. Just because a generally capitalist economic system is healthier and more innovative than a generally socialist economic system (which is true) does not mean that "the market will take care of" everything, all the time.

      If the Internet depended on "market forces," it wouldn't exist -- we'd be living in a world of multiple incompatible networks with users of any one network unable to communicate with those of others. If the highway system depended on "market forces," there would be no way in hell you could drive from one coast to the other. If education depended on "market forces," only the children of the rich would ever get an education. Etc. And if space exploration depends on "market forces," then you can kiss any chance you or your great-grandchildren have of ever getting off this planet goodbye.
      --
      The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
    2. Re:Mixed emotions... by the_Upsetter · · Score: 4, Informative
      the Interstate Highway System, the TVA, rural electrification, the Public Library system (just off the top of my head)... none of these were driven by these elusive "market forces" the original poster refers to.

      (which is not to say that they didn't precipitate in quite a little jolt for this nation's capitalists)...

      Clearly there's a bit of saliency to the argument that a little "push" by the govt. can jump-start some of these "market forces."

  6. Re:5/6 is stopping short by Justin+Cave · · Score: 5, Informative

    From a physics standpoint, getting men and material to and from the Lagrangian points would be vastly cheaper than getting them to and from the moon. Until we could utilize the raw materials of the moon to produce things, it isn't going to be cost-effective to have a moon presence.

  7. Quick! by NASAKnight · · Score: 5, Funny

    Someone file a patent on flying to the moon! I can see NASA paying some major royalties.

    --
    Fault loves the past, worry loves the future, but content enjoys the present.
  8. Re:5/6 is stopping short by blincoln · · Score: 5, Insightful

    Why not just build on the moon?

    Apples and oranges. Having a station in zero gravity is really useful for launching probes and ships from, and as a gateway between the Earth and the rest of the solar system. Having a moonbase gives you mining capabilities and so forth.

    They're both very important aspects of stepping into space, for different reasons.

    --
    "...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
  9. Re:Radiation is a solved problem by npietraniec · · Score: 4, Funny

    Lead is really heavy... Maybe? Do you know how many N*Sync members you could get in space instead of a couple of sheets of lead?

  10. Re:Radiation is a solved problem by ShavenYak · · Score: 4, Informative

    Perhaps it has to do with the fact that lead is heavy, and heavy things cost more to get into space?

    --

    Hey kids, there's only 5 days left 'til Yak Shaving Day!
  11. third brightest object in the sky by peter303 · · Score: 5, Informative

    After the Sun and Moon. Its been fascinating to watch it get brighter as they add more cylinders and panels every year.

    The station is visible in the evenings about one week a month and mornings one week a month, so the orbit can wobble over the US, Russia, Europe, and Japan. Sky & Telescope (set zip code, click on almanac) shows pass times & locations, as do other websites.

    1. Re:third brightest object in the sky by ryanvm · · Score: 5, Informative

      Here's an even better site: Heavens Above.

      It covers any location in the world (not just USA and Canada). It has fly-by data for hundreds of satellites (including ISS) and my personal favorites, the Iridium flares. If you've never seen a -7 magnitude Iridium flare, do yourself a favor and check it out. It's absolutely awesome.

      Heavens Above will tell you where to look (direction and azimuth) and when to look - accurate down to the second!

  12. New scientists. by Docrates · · Score: 5, Interesting

    If i'm to be modded down for offtopicness, well, I deserve it, but I need to get this off my chest:

    I simply can't read new scientist anymore. When the site actually loads (regardless of slashdotting), every single article they publish seems to be the scientific equivalent of the paparazzi.

    I mean, really, one thing is to have a non-peer-reviewed magazine, and an entirely different thing is to intentionally publish exagerated, ridiculous, absolutely un-proved (and almost always un-provable) "facts". Even the simplest of stories is spinned beyond recognition. If a story comes up of some scientists spotting a .00001% deviation from expected results researching *.*, right after they make clear that most likely it's due to faulty measurement equipment, New Scientist will publish that they found aliens, that they have a draft of the alien invasion plan, that Einstains's GToR is therefore void, and that in fact he himself WAS an alien trying to distract us from the truth. And then they _really_ start speculating and tell you that they infer from the inforamtion that Einstein was a shape shifter and that he was also the first husband of Melinda Gates.

    Now, I haven't read this article (not that I could even if I wanted to, NS' site goes DoS when they're linked from my cousin's non-porn website), but I'm sure I'll get more substance out of /.er's comments than NS (if you can believe that!)

    --

    There are two kinds of people in the world: Those with good memory.
  13. Re:5/6 is stopping short by Twirlip+of+the+Mists · · Score: 5, Informative

    Why not just build on the moon? Why stop at 5/6 the way to the moon?

    Because the whole point of staging at L1 is that it allows low-energy transfers to other points in the solar system. Launching a trip to Mars, for example, from L1 would require much less energy than from either the surface of the Earth, or low Earth orbit, or the surface of the moon.

    Of course, this ignores the biggest problem with the L1 point: it's unstable. A body placed at L1 will tend to either fall inward toward the Earth or outward toward the moon at the slightest push. Any space station at L1 will have to correct its position regularly, probably using simple chemical rockets. These rockets will have to be refueled periodically and so on, making for a nontrivial amount of effort to keep an L1 space station in position.

    The L4 and L5 points, on the other hand, are gravitationally stable. If a body at L4 or L5 starts to drift out of position-- due to a collision or outgassing or whatever-- the Earth-moon system will tend to pull it back to the point of stability again. But since L4 and L5 are farther from Earth than L1 is, it takes more time and energy to get there from LEO.

    --

    I write in my journal
  14. It's time to leave LEO by Hays · · Score: 5, Interesting

    The time between when Columbus "discovered" the new world and Magellen circumnavigated the globe was 30 years. It has now been 30 years since Apollo 17, the last time man visited the moon, the last time man left low earth orbit. I think it's a great failure of our race that we've dragged our feet such.

    To think that technological advance is blazingly fast in this day in age is misleading. We're not doing too well at hitting the important targets. NASA might just now be waking up to this, but it's yet to be seen if their budget wakes up to it. (Nasa funding was 4% of the national budget at the height of the Apollo program, it's less than 1% now)

    So I applaud their very recent efforts to finally mention some vague goals away from Low Earth Orbit. L1 is a fine stepping stone, but Mars is where the public eye is. Nasa administrator Daniel Goldin had some brave words about the possibility of sending men to Mars in this decade or the next, but Bush put a bean counter in charge of Nasa pretty quickly to throttle cost overruns from the ISS.

    What we really need is a president giving NASA a kick in the pants, and the funding to follow, as Kennedy did. Either that or wait around for private space exploration to become worthwhile, and we're going to be waiting quite a while in that case. Another space race? maybe China? I hope so. Because the current NASA schedule is anything but ambitious.

    1. Re:It's time to leave LEO by jonman_d · · Score: 5, Insightful

      NASA is doing this for science, and they are publically funded.

      The explorers did it in order to find/establish trade routes, and had a lot of private monies.

      See the difference? Money.

  15. Re:5/6 is stopping short by Twirlip+of+the+Mists · · Score: 5, Informative

    a space station at a LaGrange point (in this case L1) wouldn't have to use thrusters to maintain a stable orbit and would never leave it's stable orbit around the earth

    That's not true. L1, L2, and L3 are all gravitationally unstable points. A space station at L1, if nudged out of position even slightly, will tend to spiral inward toward Earth or outward toward the moon. The L4 and L5 points are the only stable Lagrangian points in a two-body system.

    --

    I write in my journal
  16. NASA couldn't even go to the moon now by pbranes · · Score: 4, Interesting
    After the Apollo missions, there was no budget to keep up the plans for the Apollo V spacecraft. If NASA wanted to land men on the moon again, they would have to reinvent the great rocket science of Wernher von Braun. NASA should just shoot for going to the moon now and establishing a science based set of missions.

    Apollo was not built around science. It was built as another battlefield of the Cold War. The space program wasn't even important until the Soviet Union beat America into space. When NASA can make routine, scientific trips to the moon, then they can concentrate on building a space station at L1 and worry about getting to Mars.

    The Space Shuttle is routine now, and usually stays within budget. NASA should build on this technology, slowly and gradually. We will learn so much more this way rather than putting a thermometer and a seismometer on the moon as quickly as possible.

    1. Re:NASA couldn't even go to the moon now by lostchicken · · Score: 5, Interesting

      Not to be picky, but this is Slashdot. Picky is what we do here. The rocket for the lunar Apollo missions was the Saturn V series booster, not the Apollo V.

      The Saturn series was used after the Lunar Apollo four times (correct me if I'm wrong). Three were Apollo CSMs (one to ASTP, two to Skylab), and one, a Saturn INT-21 (a modified Saturn V) boosted Skylab, which really was a good scientific experiment, to orbit.

      --
      -twb
  17. Home on Lagrange by whovian · · Score: 5, Funny

    To the tune of "Home on the Range"

    Home on Lagrange

    Oh, give me a locus
    Where the gravitons focus
    Where the three-body problem is solved
    Where the microwaves play
    Down at 3 degrees K
    And the cold virus never evolved.

    --
    To-do List: Receive telemarketing call during a tornado warning. Check.
    1. Re:Home on Lagrange by Speare · · Score: 4, Informative

      A well-known filk song in certain circles. Home on Lagrange by Bill Higgins and Barry Gehm in or around 1978.

      --
      [ .sig file not found ]
  18. Building Infrastructure for the Future by GreenPhreak · · Score: 5, Insightful

    Yes, it is true that the International Space Station has taken a horrendous amount of money that could've been spent on real science. I admit that I'd like to see more money spent on real science missions like probes to Pluto or Europa or on more Space-based telescopes, but unfortunately as these devices increase in size (satellites, space telescopes, probes, etc.) it becomes infeasible to launch them in a confined shuttle (I believe Chandra X-ray telescope reached the volume limits on what could be launched in one piece).

    That said, we need to be building an infrastructure for launching larger and more complex devices into space. This requires places where things can be assembled once in orbit, places such as the ISS or another station at a Lagrangian point. In and of themselves, these stations aren't spectacular, they don't produce good science and they are very expensive, but they need to be created to assist other scientific endeavors as our technology continues to develop. As an example, routers, fiber, and transcontinental backbones are expensive and to the layman, they produce no real science or pretty pictures, but they are necessary as an infrastructure over which people can do some really cool things.

    Anyway, I think that even if this doesn't get passed by congress or the things run behind schedule, it is good that we are at least PLANNING to do some really cool stuff like this.

    --
    I drink to prepare for a fight; tonight I'm very prepared. -Soda Popinksi
  19. Why get upset? by g4dget · · Score: 4, Funny

    The New Scientist is to Nature what the National Enquirer is to the New York Times. But, hey, lots of people read the National Enquirer for fun as well. Only that when people start taking it seriously that people get hurt.

  20. I thought an L space colony would look like.. by ashitaka · · Score: 5, Interesting
    --
    If you don't want to repeat the past, stop living in it.
    1. Re:I thought an L space colony would look like.. by Tablizer · · Score: 4, Funny

      Ice is a fairly good radiation shield [for window use]. There's ice on the moon. Problem solved.

      Or just keep pissing on a "starter layer" while working up there from the inside :-)

      A glass layer between the outer window and the environment rooms could perhaps keep the outer layer of water or piss cold enough to stay frozen.

      I saw a documentary on WWII guns the other day. If your gun jammed in the cold weather, then pissing on it was a common trick to get it working again.

      Piss can be a useful tool if resources are thin.

  21. what a waste of money by g4dget · · Score: 4, Insightful
    Which would you rather have? Landings on all the major planets, together with exploratory rovers, chemical analyses, and photography, and space telescopes looking for planets around nearby stars? Or a handful of aging space cowboys spending a lot of their time cleaning toilets and keeping in shape at the Lagrange point? I know which one I would rather have.

    Sure, it would be fun to go into space in person. But that's entertainment and tourism, and the best way to finance that is through private funding. It's the science, the big questions, that require government funding, and there we should concentrate on what gives the biggest payoff--and that is unmanned space flight with robotic probes.

  22. What about that newly discovered asteroid? by AaronPSU79 · · Score: 4, Interesting

    IANARS (rocket scientist) but what are the possibilities of utilizing the asteroid just discovered that shares the earths orbit for some form of station. A snippet from this article: http://news.bbc.co.uk/2/hi/science/nature/2347663. stm

    "Although only about 100 metres across 2002 AA29 may play a role in the manned exploration of space out of all proportion to its size.

    Already researchers are speculating that it could be visited by an unmanned spaceprobe or even become the first object after the Moon to be stepped on by astronauts.

    The object could tell us a lot about the composition of asteroids.

    Some have speculated that it could be nudged into a permanent Earth orbit where it could be studied at greater length."

    If you could nudge this thing into the right orbit wouldn't it make a wonderful station? Lots of room, some raw materials, and you could burrow into to escape the radiation. I understand that some asteroids are nothing more than loose collections of rocks and dust. But it's an intriguing, and plausible idea.

  23. Great ... spill the beans ... by dustpuppy · · Score: 5, Funny

    now that you have publicised the radiation risk, there is no way that Nsync singer will go into space ... and there dies our last chance of getting him sterilised and stopping him from having offspring ...

  24. Re:Can someone explain this? by Anonymous Coward · · Score: 4, Informative

    They aren't global attractors. Meaning that if I stick something on the other side of the solar system, it's going to be pulled towards Earth, not the two stable Lagrange points.

    However, they are locally stable. Meaning that anything put in that general area gets pulled into the Lagrange point. The 'general area' is mathematically defined by the gravitational equations, but you can think of it like a dip in the side of a bowl. A marble placed in the bowl rolls toward the bottom. But if you put the marble close enough to the dip, it will settle there instead.

  25. It's about bloody time! by elliotj · · Score: 5, Insightful

    I've long felt that human progress into space has been on some form of hold since the 1960s. JFK announced that we would goto the moon not many years before we actually did. Then we went back a couple of times. Then not much.

    The major achievement of the late 70s was the Space Shuttle. The major achievement of the turn of the century will be the ISS. Obviously these are significant achievements but why we haven't been back to the moon in 40 years is baffling.

    I'm very happy to see a station being considered that won't just be in orbit. I hope it is a sign of things to come. I'd really like to see a moon base in my lifetime. I don't know much about space but I'd expect it must be easier to build a big station if you build it on something.

    We need to be up there. In large numbers. We need private industry up there. NASA should be focussing on putting human living quarters in space and providing transportation up there. I think there should be some kind of space oriented general contracting agency focussing on getting as many people up there for as long as possible. We need scientists, professors, entrepeneurs, the media...all sorts of people to go up and see what we can make of it.

    If space really is the new frontier, it should be accesible. I hope this is a step in the right direction.

  26. Re:Replacement for ISS? by Yorrike · · Score: 4, Interesting
    The USA: Taking the I out of ISS.

    It's like a playground spat: "We don't want you bringing your friends to our treehouse, it's for members only!"

    Of course, the reason Russia can afford to keep contributing to the ISS, is because of those "jackasses". The US needs to stop whining. Russia obviously has a huge interest in the ISS, or they wouldn't bother selling rides to finance their parts of the project.

    --

    Looks can be deceiving. Or CAN they?

  27. Why not just go to the moon. by phriedom · · Score: 5, Interesting

    I thought Lagrange points collected a lot of dust, which would be bad for optics. Its not like you can vacuum that stuff up either. If you are 5/6ths of the way to the moon already, why not just go the rest of the way? A luna's gravity keeps the dust down and provides many other benefits. I expect Luna would also supply SOME building materials, like maybe 10 foot thick rock walls to stop cosmic rays, for example. The lunar gravity would be a disadvantage for launching other missions from there, but perhaps that could be compensated for.

    If there are more informed people out there who see what I don't, I'd love to hear it.

    --
    Don't moderate flamebait as Troll. Know the difference or you will be Meta-moderated.
    1. Re:Why not just go to the moon. by Twirlip+of+the+Mists · · Score: 5, Informative

      I thought Lagrange points collected a lot of dust, which would be bad for optics.

      L4 and L5 are gravitationally stable points, so there may be collections of dust there. (In the Jupiter-Sun L4 and L5 points, there are collections of asteroids.)

      But L1, L2, and L3 are all gravitationally unstable. A body at one of those three points will tend to fall away from the point rather than staying in it.

      L4 and L5 are like being at the bottom of a depression: whichever way you go, gravity tends to pull you back toward the middle. L1, L2, and L3 are more like being at the top of a hill. If you're right at the very center, you're fine. But if you're even slightly off-center, gravity will pull you down the hill.

      In theory, L1 ought to be the cleanest point between the Earth and the moon. Nothing can stay in orbit at L1 without active station-keeping.

      --

      I write in my journal
  28. Re:Radiation is a solved problem by RayBender · · Score: 5, Informative
    I don't understand why NASA does not employ lead shielding to protect its astronauts.

    Fair question, but one with a fairly simple answer. Lets do some numbers...

    To within a factor of a few, what matters in radiation shielding is "surface density", i.e. how many grams of material per square centimeter there are in your shield. So you can have a thick shield of light material, or a thin shield of dense material; for the same area they will provide the same shielding effect if they have the same mass.

    Say for a moment that you want as much shielding as provided by the Earths atmosphere; that works out to be about 10 tons/square meter. (If you SCUBA dive: remember that the pressure goes up by 1 atmosphere for every 10 meters of depth. A 10x 1x1 meter column of water weighs 10 tons.) Those ten tons/m2 can be in any form you want: a 10 km thick air shield, 10 meters of ice, 2 meters of rock, or a meter of lead.

    So, you want to put a couple of guys in a spaceship and send them to Mars? Well, put them in a cramped tube, say 10 meters long and 3 meters in diameter. That gives you about 100 square meters of surface area.... or 1000 tons of shielding.

    At current prices it costs about $20,000 to put a kilogram of material into low Earth orbit. The biggest rocket flown to date can put about 100 tons into orbit. With current technology you either hit up Bill Gates for the 20 billion, or you can skimp on the shielding. The space station skimps by a factor of 300 (you get a years ' worth of background radiation in a single day). You could also play games like have most of the spacecraft lightly shielded, but have a lead-lined "storm shelter" for the times when solar flares erupt. This works because much of the radiation comes in bursts. However, it isn't useful for going to places with continuous high levels of radiation, like Jupiter.

    That's why we need a new and cheaper space launch system.

    --
    Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
  29. Acceptable risk? by Stoptional · · Score: 5, Interesting

    Many here have spoken of the "insane" "horrendous" "crazy" amounts of money spent on IIS. How many think that this money was spent *mostly* to make sure that no one died?

    Was it a good thing to spend that money on? Is the IIS over-engineered in favour of preventing un unfortunate death? (Aside - How many of you, after viewing the interior of an Apollo era craft, would still go into space in one of those?)

    Let's look at a little history. If during the 18th century, we had spent an equivalent amount of dough on sailing ships (with the (un)stated goal of preventing deaths (monarchs HATE to look bad)) I think we'd still be looking for our assholes with a mirror. We'd never have left Europe. The economy of the day would not have tolerated it.

    My father-in-law was one of the Canadians who helped develop the nuclear power station system called CANDU. His stories are quite telling. His take on risk? - during development of CANDU the engineering studies required would fill a couple of banker's boxes. Today, those studies would fill a small stadium. With a exponential rise in cost. Why? What's the return? A couple of lives? A dozen lives?

    My point is - we have tried to reduce the risk to zero and this is not only stupid, but unwise. Stupid because there will always be a risk. How much money are we going to let timid politicians/bureaucrats spend on that last .005% of risk reduction? Unwise, because we lose the ability to pursue our dreams. We're deadlocked.

    "Acceptable risk" is a term that has been lost from the West's vocabulary and it is time to bring it back.

    --
    Stoptional
  30. Re: What's L4,5? by Graff · · Score: 5, Informative

    L1 is about 5/6 of the way to the moon, along a direct line from the earth to the moon.

    L2 is opposite the L1, over the far side of the moon from the earth.

    L3 is close to the moon's orbit around the earth, but on the opposite side of the earth from the moon.

    L4 and L5 are also in the orbit of the moon around the earth, but one is 60 degrees ahead of the moon in its orbit and the other is 60 degrees behind.

    You can find more information at this web site and there is even more detailed information to be found here

  31. We should think hard before gunking up Lagranges by Dr.+Spork · · Score: 4, Interesting
    You know, a couple of rounds of budget cuts later, their next grand space station will be another useless pile of expensive junk just like the first one. The problem is that it will be squatting one of only five stable points at which long-term space projects can be built.

    Well, I don't like it. What gives NASA the right to squat on what is probably one of the five most valuable places in the universe (from our perspective)? Will there be a deal arranged that in 50 years, when a better space agency comes up with a better project for the liberation point, they'll move their junk out of there? There had better be. Seriously, the UN has to get on this fast. Right now, the USA has basically called dibs on two of the five liberation lunar liberation points, plus there's that second-generation telescope that they want to put into the liberation point behind the earth, where it is always shielded from the sun. Well, this is the ideal place to build a telescope, and once something is there, everybody else, even people with a better telescope idea, are shit out of luck. They'll have to spend billions to make heat shielding because NASA is squatting on the one spot where the heat shielding is natural (permanently in the shadow of Earth).

    If I were the UN, I would set a squatting limit of 30 years on any given liberation point. If somebody wants to use it after that, whoever was there before has to get the fuck out and clean up after themselves. I think it's likely that in 30 years all the liberation points will have something, and in another 30, countries will be duking it out over who gets to go there next. The people who want it most will have to compensate the other people who want it. In any case, this is not too soon to be thinking about making international laws about this.

  32. Telescopes for high-energy radiation. by Christopher+Thomas · · Score: 5, Informative

    My take on the subject is that we don't have any materials heavy/stable enough to reflect high energy radiation.

    The problem is that conventional materials of all types misbehave as photon energy substantially exceeds the chemical binding energies. You go from having materials acting like ideal classical conductors or dielectrics interacting with photons that act more or less like classical EM waves [normal reflection and transmission], to having materials that act like a set of quantum energy levels and photons that act like particles [photoelectric effect], to having materials that act like a diffuse sea of particles that scatter photons which also behave like particles [Compton scattering].

    As the valence shell binding energies in atoms are at most on the order of a few tens of eV, there is a hard upper limit on the frequency of radiation that conventional optical elements made of normal matter can handle.

    The limit's mushy in one respect, in that grazing-incidence devices see an effective frequency that's inversely proportional to the angle of incidence. However, practical devices limit the benefit of this to between a factor of 10 and a factor of 100 (so you can see some x-rays, but gamma rays are still tricky).

    Non-conventional optics made of normal matter can still work under some conditions. Because the inter-atomic spacings in crystals are in the same ballpark as high-energy photon wavelengths, you can get diffraction occurring when an x- or gamma-ray beam passes through a crystal (due to scattering off of inner-shell electrons and the nuclei). This is commonly used to identify materials (x-ray diffraction patterns have been used to image atoms in everything up to and including crystals of viruses). Gamma ray telescopes using crystalline blocks to construct diffractive optics have been built.

    Lastly, the final and most difficult way to cheat involves using plasma as a mirror. As it's a gas of free ions, it should have near-perfect reflection even at high wavelengths (subject to a few probably-nontrivial conditions). Keeping a cloud of ions confined to an optically flat surface is left as an exercise for the reader.

  33. Bottom line: stupid idea by GileadGreene · · Score: 4, Interesting
    Putting a space station at the Earth-Moon L1? snort What yahoo at NASA HQ came up with that one? They obviously didn't bother to check with anyone who actually knows anything about libration points.

    Why is this stupid? Here's why:

    1. The Earth-Moon L1 is an unstable point. Put something there (if you can), and it will immediately drift away.
    2. Yes, there are these things called halo orbits and lissajous orbits, that are essentially periodic orbits around the libration points, but their dynamics are very complex.
    3. Did I mention that the dynamics in this region is very complex? Actually getting onto a halo or liss is not anywhere near as simple as computing a hohmann transfer - it takes a lot of careful precalculation. The region around the L1 point (and all libration points) is governed by three-body dynamics - highly nonlinear, potentially chaotic, very messy to deal with.
    4. Even assuming that you successfully put your space station at L1, how the hell are you going to get anything else to rendezvous with it? (see previous point) I can't even imagine trying to carry out docking maneuvers in that kind of gravitational environment.
    5. The reason it's cheap to get to a halo (the efficient "superhighway" they keep talking about) is that you can hop on the stable manifold associated with the halo (essentially a sheaf of trajectories that asymptotically approach the halo) where it passes near the earth. But this cuts both ways, since the halos also have unstable manifolds that lead away from the halo (and are also cheap to get onto). One small burn in the wrong direction, and "whoops!", you're on the unstable manifold leading away from the halo and off to who knows where.

    So what do you have when you break it down: A dynamically complex region of space that will make proximity maneuvers extremely difficult to perform. And if you make one small mistake in those difficult maneuvers, you're basically headed for Pluto. Bottom line: L1 is just about the stupidest place to put a space station that you could pick.

    1. Re:Bottom line: stupid idea by jpmorgan · · Score: 5, Interesting
      Let's see, NASA, you know the people who send space probes galavanting around the solar system slingshotting around the sun, planets, moons etc... to reach their final destination thinks that building a space station in an L1 point is a good idea. Obviously, you know better than NASA and don't try to figure out why they'd pick L1 over say L4 or L5. *sigh*

      While maintaining position at L1 is technically more challenging than maintaining position at L4 or L5, it has a higher payoff. For one, you won't be trying to build your space station in a veritable gravel pit in space. Secondly, it's trivial to launch vehicles from the point - you just let them go and they'll drift off without active station keeping. And considering how the intended primary purpose would be as a place to launch other missions from, that's a slightly useful thing.

    2. Re:Bottom line: stupid idea by p3d0 · · Score: 5, Insightful
      Others have already pointed out various reasons that your smug troll is off-base. I'll just add that it's dangerous to put things in the L4 or L5 points because they are stable, and therefore filled with potentially dangerous space junk.

      If it's really so hard to put things at L1 and keep them there, you better go tell the SOHO team who have successfully kept that satellite at the Sun-Earth L1 point for almost 7 years now, without ever being "headed for Pluto".

      --
      Patrick Doyle
      I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
  34. Re:5/6 is stopping short by teridon · · Score: 5, Informative
    I have mod points, but since I work on SOHO and someone modded the parent "Informative", I have to straighten things out :)

    GiliadGreene has made some good points already about SOHO being in a halo orbit around the L1, not at the actual L1 "point".

    Orbit corrections are performed every 17 weeks (four months, not one).

    The halo orbit is much saner than trying to stay at the L1 point, and it attenuates solar interference. Ironically, the COMSAT link that DSN uses to get data from Madrid to California gets more solar interference than the spacecraft to ground link.

    --
    I hold it, that a little rebellion, now and then, is a good thing. -- Thomas Jefferson