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posted by martyb on Wednesday December 20, @11:27AM   Printer-friendly
from the say-hi-to-Vir-Cotto-for-me dept.

NASA thinks that the technologies needed to launch an interstellar probe to Alpha Centauri at a speed of up to 0.1c could be ready by 2069:

In 2069, if all goes according to plan, NASA could launch a spacecraft bound to escape our solar system and visit our next-door neighbors in space, the three-star Alpha Centauri system, according to a mission concept presented last week at the annual conference of the American Geophysical Union and reported by New Scientist. The mission, which is pegged to the 100th anniversary of the moon landing, would also involve traveling at one-tenth the speed of light.

Last year, Representative John Culberson called for NASA to launch a 2069 mission to Alpha Centauri, but it was never included in any bill.

Meanwhile, researchers have analyzed spectrographic data for the Alpha Centauri system and found that small, rocky exoplanets are almost certainly undiscovered due to current detection limits:

The researchers set up a grid system for the Alpha Centauri system and asked, based on the spectrographic analysis, "If there was a small, rocky planet in the habitable zone, would we have been able to detect it?" Often, the answer came back: "No."

Zhao, the study's first author, determined that for Alpha Centauri A, there might still be orbiting planets that are smaller than 50 Earth masses. For Alpha Centauri B there might be orbiting planets than are smaller than 8 Earth masses; for Proxima Centauri, there might be orbiting planets that are less than one-half of Earth's mass.

In addition, the study eliminated the possibility of a number of larger planets. Zhao said this takes away the possibility of Jupiter-sized planets causing asteroids that might hit or change the orbits of smaller, Earth-like planets.

(For comparison, Saturn is ~95 Earth masses, Neptune is ~17, Uranus is ~14.5, and Mars is ~0.1.)

Also at BGR and Newsweek.

Planet Detectability in the Alpha Centauri System (DOI: 10.3847/1538-3881/aa9bea) (DX)


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  • (Score: 4, Insightful) by Snotnose on Wednesday December 20, @11:52AM (7 children)

    by Snotnose (1623) on Wednesday December 20, @11:52AM (#612251)

    Congress can barely let NASA stick to a 4 year plan, no way will a 50 year plan come to fruition.

  • (Score: 2) by isostatic on Wednesday December 20, @11:55AM (3 children)

    by isostatic (365) on Wednesday December 20, @11:55AM (#612252) Journal

    Yes, funding for a launch date in 10 presidential elections time certainly will work.

    I suspect that Apollo would have been shelved had JFK not got killed in 1963.

    • (Score: 0) by Anonymous Coward on Wednesday December 20, @02:50PM

      by Anonymous Coward on Wednesday December 20, @02:50PM (#612301)

      Was working for Kennedy to ensure the space program went through!

    • (Score: 2) by PinkyGigglebrain on Wednesday December 20, @08:30PM (1 child)

      by PinkyGigglebrain (4458) on Wednesday December 20, @08:30PM (#612520)

      I heard somewhere that within a few months of Kennedy's speech about America going to the moon he and his advisors were discussing how they could do joint mission to the moon with the USSR due to the cost of America going it alone. If Kennedy had lived things would have likely been very different, either a multinational space program or the USSR beating the US to the moon, and likely collapsing economically much sooner than it did.

      --
      "Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
      • (Score: 2) by frojack on Thursday December 21, @12:48AM

        by frojack (1554) Subscriber Badge on Thursday December 21, @12:48AM (#612645) Journal

        In the end it wasn't that expensive.
        We managed to carry out an expensive war in a distant land all through the moon race and beyond.

        In the end we lost the war, but had already one the race.

        --
        No, you are mistaken. I've always had this sig.
  • (Score: 5, Interesting) by Runaway1956 on Wednesday December 20, @11:58AM (14 children)

    by Runaway1956 (2926) Subscriber Badge on Wednesday December 20, @11:58AM (#612254) Journal

    About 40 years travel time (assuming the vehicle achieves .1c quickly, and can brake quickly, which is unlikely, so add a couple years for accel and decel) then we wait about 4 years for any radio transmissions to come back to us. That isn't quickly enough to make me happy, but at least people are thinking in the right direction. Expect some kind of results around 2110 to 2115, if everything goes right. There are babies being born today who might live long enough to see headlines about newly discovered planets in the Centauri systems.

    We could get some inconclusive results sooner than that, presuming that sensing equipment is focused on the system during travel. But, about the time the sensors start getting a good picture, it will be time to turn and burn, meaning, the sensors will be pointed at earth, rather than Centauri. And, no, I don't think that swiveling the sensors will give a good picture during deceleration. There's going to be a fire right there, in the way. I guess it will be a good time to see what our own system looks like from interstellar space.

    Of course, we can also survey portions of the galaxy outside of the line-of-sight travel path. Parallax is a beautiful thing - having sensors outside of the solar system is likely to tell us interesting things about other systems, as well. Maybe we have a lot of distances figured wrong, because our measuremaent base is just to damned small for accuracy?

    --
    #Hillarygropedme
    • (Score: 1, Funny) by Anonymous Coward on Wednesday December 20, @12:03PM (4 children)

      by Anonymous Coward on Wednesday December 20, @12:03PM (#612259)

      That isn't quickly enough to make me happy

      Oh, get real! Nothing, absolutely nothing in this world is made to make you happy.

      • (Score: 3, Funny) by Runaway1956 on Wednesday December 20, @12:27PM (2 children)

        by Runaway1956 (2926) Subscriber Badge on Wednesday December 20, @12:27PM (#612263) Journal

        Now and then, something makes me smile, if not really happy. https://pics.me.me/cantafford-to-feed-and-house-please-spay-or-neuter-your-14920440.png [pics.me.me]

        --
        #Hillarygropedme
        • (Score: 0) by Anonymous Coward on Wednesday December 20, @12:44PM

          by Anonymous Coward on Wednesday December 20, @12:44PM (#612266)

          All good until you realize that this is only incidental.

          By the example you chose as an feeble attempt of a rebuttal, you implicitly admit that even what you are making (and over which you should have a modicum of control) is not making you happy.

          Merry Christmas, old sod, may your next year plastics come better that this year's - not like you'll benefit from it, but at least you can chalk one as remarkable enough to justify your life on this Earth.

        • (Score: 2) by bzipitidoo on Wednesday December 20, @05:58PM

          by bzipitidoo (4388) on Wednesday December 20, @05:58PM (#612411) Journal

          Conservatives hate family planning, especially abortion. Now the truth comes out. They like family planning just fine when applied to liberals only!

          Anyway, we need longer lifespans. If all goes well with that plan, it'll be 2113 before any data comes back. Even today's 9 year olds probably won't be around in 2113.

      • (Score: 0) by Anonymous Coward on Wednesday December 20, @07:06PM

        by Anonymous Coward on Wednesday December 20, @07:06PM (#612454)

        Make it a congressional fact-finding trip and I'll be happy.

    • (Score: 3, Interesting) by zocalo on Wednesday December 20, @01:28PM (1 child)

      by zocalo (302) on Wednesday December 20, @01:28PM (#612280)

      There are babies being born today who might live long enough to see headlines about newly discovered planets in the Centauri systems.

      Assuming there are any such planets, then there are probably plenty of full-grown adults around today that will live long enough to hear about them, maybe even called Runaway1956; just because Kepler and other planet hunting projects haven't found them yet, doesn't mean they won't have by the time this probe gets there (assuming it even gets sent). Whatever instrument package a probe like this carries probably needs to be fairly heavily biased towards things that can only be done with a probe in-situ or there's a risk that it'll all be one big "Meh!" when it eventually arrives because of advances in observations we can do from right here in the Sol system while it was in transit. For comparison, NASA launched the Voyager probes fourty years ago this year so it'd be as if the data and (by modern standards) incredibly low-res images from that mission wasn't even due to start trickling in for a few more years (Jupiter in 2019, Saturn in 2020/21, Uranus in 2025, and Neptune in 2029) compared to what we can achieve with today's ground and LEO based observatories.

      --
      UNIX? They're not even circumcised! Savages!
      • (Score: 2) by JoeMerchant on Wednesday December 20, @03:50PM

        by JoeMerchant (3937) on Wednesday December 20, @03:50PM (#612335)

        You can't give the natives smallpox using a telescope. Many things require a physical presence, and even if the first mission doesn't do all the things, it will be establishing that physical presence capability.

    • (Score: 3, Funny) by Bot on Wednesday December 20, @02:08PM (1 child)

      by Bot (3902) Subscriber Badge on Wednesday December 20, @02:08PM (#612290)

      Also many unknown other factors into play.
      For example, a possible scenario is the probe returning ahead of time at approx. 5c with "KEEP YOUR DAMN JUNK ON YOUR OWN SIDE, CARBONBAGS" hastily engraved over it.

      • (Score: 2) by Bot on Wednesday December 20, @02:35PM

        by Bot (3902) Subscriber Badge on Wednesday December 20, @02:35PM (#612297)

        Not to mention the dangerous wooshing by of the probe in a crazy return path at 40c, and 9 year after that, a radio announcement coming from outer space:

        "ZERO FIFTEEN, HAHAHA"

    • (Score: 2) by JoeMerchant on Wednesday December 20, @03:39PM (4 children)

      by JoeMerchant (3937) on Wednesday December 20, @03:39PM (#612328)

      Too lazy to read the article, but assuming that 0.1c is going to require something other than fire for propulsion. Whatever is providing the propulsion would likely distort long range sensing apparatus, but nothing says that it has to "burn" 100% of the time - if there's a 5 year decel period, they might burn for a month, then stop for a few hours to take a picture and transmit it, then resume the burn.

      Just transmitting a picture from that distance is going to be an interesting challenge. Almost as challenging as retaining socio-political stability sufficient to fund the Earth-side support (data reception and analysis) station that long / far in the future.

      • (Score: 2) by Runaway1956 on Wednesday December 20, @04:38PM (3 children)

        by Runaway1956 (2926) Subscriber Badge on Wednesday December 20, @04:38PM (#612352) Journal

        At a guess, the fastest way to do it, would be to use a YUGE conventional rocket array at this end, and reach max velocity pretty quickly. Deceleration would take vastly more time, using solar sails and something like an ion engine. But, that's just a guess. I haven't read the article either. ;^)

        --
        #Hillarygropedme
        • (Score: 0) by Anonymous Coward on Wednesday December 20, @07:00PM (1 child)

          by Anonymous Coward on Wednesday December 20, @07:00PM (#612449)

          But, that's just a guess. I haven't read the article either. ;^)

          Yes, we know. This much is obvious. When the topic is interstellar rocket science, I always turn to Runaway!

          • (Score: 2) by JoeMerchant on Thursday December 21, @12:14AM

            by JoeMerchant (3937) on Thursday December 21, @12:14AM (#612636)

            Sadly, most articles like this are short on the underlying science, engineering and state of development of the various promising technologies.

        • (Score: 2) by JoeMerchant on Wednesday December 20, @11:55PM

          by JoeMerchant (3937) on Wednesday December 20, @11:55PM (#612626)

          I think conventional YUGE rockets hit an asymptote of diminishing returns long before they get to 0.1C. Voyager is only doing Mach 50, and a lot of that is due to gravity assist. Chemical energy release makes hot gas, so there are mach concerns even if you can increase the density and decrease your mach number, pretty quickly we're going to run out of alloys that can contain such a pressures.

          The solar sail decel is a nice thought, but somehow I doubt it would be enough - very little power coming from the sun until the last few days of approach at 0.1C.

  • (Score: 2) by c0lo on Wednesday December 20, @11:59AM (15 children)

    by c0lo (156) Subscriber Badge on Wednesday December 20, @11:59AM (#612255)

    At 0.1c max speed, it'll take longer than 45 years - if it doesn't whizzes by at destination and needs to break for an orbital insertion, it's more like 70-something years in an acceleration-decelleration travel.

    • (Score: 2) by JoeMerchant on Wednesday December 20, @03:47PM (6 children)

      by JoeMerchant (3937) on Wednesday December 20, @03:47PM (#612333)

      There are questions of what percentage of the voyage is accelerating, what's the power source, etc. Chemical rockets won't be taking anything to Mach 88,000.

      • (Score: 2) by c0lo on Wednesday December 20, @04:27PM (1 child)

        by c0lo (156) Subscriber Badge on Wednesday December 20, @04:27PM (#612348)

        There are questions of what percentage of the voyage is accelerating

        Relatively short acceleration. Reason: deceleration stage will be resource-strapped, will need to take longer.

        what's the power source,

        Multiple for acceleration. Not too many choices for the deceleration leg.

        • (Score: 2) by JoeMerchant on Thursday December 21, @12:04AM

          by JoeMerchant (3937) on Thursday December 21, @12:04AM (#612627)

          I know, we'll use Einstein brakes - just break something Einstein said and dissipate momentum into the fabric of space-time.

      • (Score: 3, Informative) by aiwarrior on Wednesday December 20, @04:48PM (3 children)

        by aiwarrior (1812) on Wednesday December 20, @04:48PM (#612356)

        Nitpick, you do not have mach numbers in vacuum, as the mach number is dependent on the speed of sound which is dependent on fluid density which is irrelevant in the vacuum.

        • (Score: 2) by JoeMerchant on Wednesday December 20, @11:49PM (2 children)

          by JoeMerchant (3937) on Wednesday December 20, @11:49PM (#612617)

          There's a mach number in the rocket nozzle, especially if you're burning something with oxygen.

          The only way this has a hope of working is with plasma-ion, or EM drive, or preferably something better than either of those has even begun to promise.

          Aero-braking on the other end down from 0.1C would be bold, and potentially very rude to the locals.

          • (Score: 2) by frojack on Thursday December 21, @01:11AM (1 child)

            by frojack (1554) Subscriber Badge on Thursday December 21, @01:11AM (#612654) Journal

            Which locals? And which aero target?
            Sounds like there are a lot to choose from, Do you choose some big gas ball planet, or the first planet that radiates a non natural radio wave?
            Or do you program it to calculate a grand tour and aero-brake a little here and a little there.

            All your calculations are going to have to be all done on board with computers that by then live only in historical documents, presumably shielded by feet of lead, and powered by a long lived nuclear reactor.

            --
            No, you are mistaken. I've always had this sig.
    • (Score: 2) by Immerman on Wednesday December 20, @03:48PM (7 children)

      by Immerman (3985) on Wednesday December 20, @03:48PM (#612334)

      That's assuming something resembling an "accelerate halfway there, then start decelerating" flight path that only peaks at 0.1c, which is probably very unlikely, since it involves carrying a huge amount of reaction mass, and the supply power to accelerate it (assuming ion drive, every other proven technology is even more ludicrous)

      More realistic astronavigation tends to involve high-impulse burns at points of optimum energy/momentum exchange - for example diving as close to the sun as possible and burning hard where the momentum gain will be highest.

      Even more promising are external propulsion systems, which avoid the crippling nonlinearities of the rocket equation. For example a giant, incredibly thin mylar mirror "sail" being blasted by an extremely powerful laser over the course of months or years - all the power and momentum can then be produced at the stationary launch facility, while the craft reaps the benefits. Deceleration is still an issue, but if the craft can withstand a close solar approach the same mirror can help considerably by diving (almost) directly at the target sun, using its photon pressure (and solar wind) to decelerate.

      • (Score: 2) by c0lo on Wednesday December 20, @04:06PM (6 children)

        by c0lo (156) Subscriber Badge on Wednesday December 20, @04:06PM (#612342)

        That's assuming something resembling an "accelerate halfway there, then start decelerating" flight path that only peaks at 0.1c, which is probably very unlikely,

        Symmetric acceleration/deceleration legs are indeed unlikely. The acceleration part can indeed benefit from "local conditions", the deceleration part is more resource restricted - I reckon it should take longer for a successful insertion at destination. Even more so since a remote control in realtime is impossible.
        For sure, the prove will need to carry a telescope for 9-years-ahead observation to allow a sorta extreme lag remote control - and unfortunately an energy source large enough to transmit back whatever it "sees".

        • (Score: 2) by Immerman on Wednesday December 20, @06:00PM (5 children)

          by Immerman (3985) on Wednesday December 20, @06:00PM (#612412)

          Assuming we plan to actually insert into a stellar orbit, rather than making fly-by observations, then there's no need real advantage to remote control - space is empty, planetary motion predictable, and orbital navigation simple. We already know fairly accurately the mass of the star based on the orbital characteristics of its satellites, and thus its gravitational characteristics. And that will only improve as we build better telescopes here. We might try a slingshot maneuver around a planet or two as we decelerate - and that may introduce more variability since they need to have moons we can see clearly to accurately measure planet mass, but in 50 years it's a good bet well be able to make at least reasonable measurements of such things.

          Meanwhile, there's probably not much point in sending a telescope big enough to be of any use during the journey. Unless its truly huge we'll be able to see a lot better with huge telescopes here. (And if it *is* truly huge, we'd do a lot better sending it out to 600AU or so in the opposite direction and using it and our sun as a gravitational lens telescope) What you want a probe for is to be able to get close - to capture photos from orbit which aren't detail constrained by the limitations of physics or achievable construction costs. Maybe even physical sampling of atmospheres.

          And power - well at the far end you have access to cheap, limitless solar power, especially if you have a light-sail you can re-purpose to focus light onto your solar panels. Probably you want just enough on-board power to keep the thing from freezing up in interstellar space, and maybe send back short bursts of whatever information it can learn about the interstellar medium. You could just wait and have it send back everything once it reaches it's destination, but you also probably don't need a ridiculous amount of power to communicate, especially in short bursts. Say, a very tight-beam laser that transmits at a frequency that's as close as possible to being completely dark in the target star's spectrum.

          • (Score: 2) by Immerman on Wednesday December 20, @06:04PM

            by Immerman (3985) on Wednesday December 20, @06:04PM (#612418)

            I should have finished that last thought more clearly - you only need a small transmitter if the frequency it's transmitting on is dark AND you have a big honking high-power telescope pointed at it for purposes of receiving transmissions. Which is also helped by communicating in rare short bursts, since you don't want to constantly tie up your very expensive telescope listening to some probe which has very little to say.

          • (Score: 2) by c0lo on Wednesday December 20, @07:36PM (3 children)

            by c0lo (156) Subscriber Badge on Wednesday December 20, @07:36PM (#612474)

            Assuming we plan to actually insert into a stellar orbit, rather than making fly-by observations, then there's no need real advantage to remote control - space is empty, planetary motion predictable, and orbital navigation simple.

            TFS just says there may be quite large rocky planets we don't know about.
            Given that we've seen Pluto only in 1930, I have a hunch we may not see quite significant (in terms of gravitation, capable of sending our probes astray) bodies around Alpha Centauri stars, no mater how much we'll advance with the telescopes.

            Meanwhile, there's probably not much point in sending a telescope big enough to be of any use during the journey.

            Large is relative when it comes to the cosmic void and longish (as in days/weeks) exposure times.

            And power - well at the far end you have access to cheap, limitless solar power, especially if you have a light-sail you can re-purpose to focus light onto your solar panels.

            Look, a smallish 100kg probe at 0.1c will have a kinetic energy of 45e15J (relativistic kinetic energy).
            If you start breaking on Pluto's orbit (40AU) from 0.1c you will have about 11 hours to reach almost zero kinetic energy for an orbit around the star (Earth around the Sun is 30500 m/s = 0.001c). Say that you shoot around the star and continue deceleration, lets make 22 hours for deceleration.
            You will need to loose those 45e15J in 79200 seconds - assuming constant energy dissipation, this means you'll need to lose 568181818181 J/s.
            Translation: dissipate the kinetic energy at a rate of 568 TW.

            I really don't know any material able to support an energy exchange of 500TW using a mass of 100kg.
            Seems very likely that you will need to apply the brakes a lot earlier than 40 AU

            ---

            Solar sail, you say? The radiation pressure goes down with the square of distance to the source - Earth gets about 1.4kW/sqm (in space), Pluto get 0.9W/sqm.
            The area of the sail that will use 1W/sqm to put on a 568 TW brake is a square of 753 km each side.
            Let's say the 99% from the entire probe is dedicated to the sail, with only 1kg of useful payload.
            At 99 kg/568e9 sqm is a sail with nanometer thickness - I really doubt that sail can offer enough rigidity to connect and put a drag without tearing itself apart from your 1kg payload
            If you start braking later, when the radiation pressure is higher? Well, yeah, but then you'll have less time to brake, which means higher power to dissipate.

            • (Score: 2) by Immerman on Wednesday December 20, @09:14PM (2 children)

              by Immerman (3985) on Wednesday December 20, @09:14PM (#612541)

              Do you have any idea how hard it is to pass close enough to a planet to have your path substantially modified by its gravity? Especially something as tiny as Pluto? Meanwhile we're already beginning to directly image planets around other stars, and have telescopes in the works that will actually be designed for the job and do a radically better job of it.

              That's not to say it's *impossible* that we'd just happen to graze close enough to something we hadn't spotted to foul up an insertion path enough that automated adjustments couldn't correct for it - just that the increase in cost of launching a probe capable of seeing it soon enough to be of any use would completely dwarf the cost of the original probe. You talk about a 100kg probe - while most every idea I've heard is closer to a few grams - a basic sensor package and a communication system that, with luck and an incredible receiver, we could just barely hear reliably.

              Consider - that 45e15J (12.5 TWh) would have to be provided on this end to launch a 100kg probe, probably over the same 11 hours unless you have a secondary launching facility on Pluto to accelerate it toward the sun to begin with. That means that even at 100% efficiency you'd be talking about spending 11 hours dedicating 6% of global power consumption to launching the probe. Heck, can you even imagine the laser needed to deliver that kind of power? Or that anyone would want such a powerful space-based weapon to be built?

              I think the usual plan is that most of the mass is an ultra-thin light-sail used for launching and solar-braking, which then gets ejected at closest approach while the sensor package micro-probe fires its own braking thrusters at the point of closest approach/maximum payoff, expelling most of its remaining mass in the process. Ideally you'd like to use the solar sail as reaction mass, but you'll probably be hard pressed to find an effective way to do so.

              As for the solar sail - at 0.77mg/m^2, 99 kg of graphene would cover only 128e6 m^2 with only at 0.33 nm thickness - though of course at 42N/m it's probably far stronger than needed for most of the sail, so we've got plenty of overhead to work with to make it more reflective and/or larger. You can also turn a lot of that incredible tensile strength into rigidity by spin-stabilizing it - since you're diving straight at the sun, so you don't need to be able to reorient the sail. And the sail is mostly decelerating itself, only 1% of the total deceleration needs to be transmitted to the comparatively tiny probe

              Meanwhile the trick to solar braking is embedded in that same inverse-square law - you have to get close to the sun. You did miss the fact that solar sails effectively double the energy, since it sends it back the way it came, not that it changes things dramatically. At Earth's orbital distance it'd take 12.5TWh/(1.4kWh/m^2 * 2 * 128e6 m^2) = ~35 hours. Not enough. At Mercury's orbit radiation is 6.7x denser - so only about 5 hours - better, but too little to late. At say, 10 solar radii though - there the radiation density is 467 times higher, and would require only 4.5 minutes. Way more than we need, since we've been decelerating all the way in, so we can actually stay at a safer distance. Meanwhile graphene melts at somewhere over 5000K, while the sun is only 5777K - so, with a nice reflective surface it should last long enough to do the job.

              • (Score: 2) by c0lo on Thursday December 21, @01:17AM (1 child)

                by c0lo (156) Subscriber Badge on Thursday December 21, @01:17AM (#612657)

                You can also turn a lot of that incredible tensile strength into rigidity by spin-stabilizing it

                Spin stabilisation is a nice.... ummm... twist, so to speak ;)
                Except...

                with only at 0.33 nm thickness so we've got plenty of overhead to work with to make it more reflective and/or larger.

                We'll need that overhead and something more. At 0.33nm, the sail will be transparent for light.
                Even a metallic film will be transparent - has to do with the skip depth [wikipedia.org] - the depth on which the electric/magnetic field intensity drops to e-1 in a bulk conductor. Optimally, you need something on the order of λ/2 film thickness to maximize the reflection by constructive interference [wikipedia.org] - so you'd be playing in the hundred nanometers range . You may go suboptimal, but in any case not to the level of 0.33nm; at that thickness, the light simply "flows" through the sail as if the sail is non existent.

                the sensor package micro-probe

                Microsensors are fine.
                What is not fine at the micro dimension is the "call-home" feature. 'Cause we do want to get some info back from that probe, something that's not drowned by the EM emission of 3 starts - one of which is a red dwarf, cooler, emitting with peaks IR and microwave.
                If any of the planets there has atmosphere and auroras, that'll be another source of noise in longer range RF.

                • (Score: 2) by Immerman on Thursday December 21, @02:57PM

                  by Immerman (3985) on Thursday December 21, @02:57PM (#612806)

                  Actually, a single layer of graphene blocks ~2.5% of light, pretty much across the spectrum, and the effect stacks - so at 10nm (30 layers) you're blocking ~53%. Working out something more opaque (and reflective rather than absorbent) will no doubt be a challenge. We'll have to see see what material scientists can accomplish given a motive.

                  Transmission will indeed be a challenge, I've got no answers for that, except that RF is almost certainly out - as you say, there's not really any quiet place in the spectrum. I'd bet on a carefully tuned laser myself. And that communication would be strictly one-way - With the mass and power constraints I'd expect it'd be nigh-impossible for it to detect an interstellar signal. Though... perhaps the launching laser could be tuned and modulated to be readily detected at that distance.

                  And hey, even if we never heard back from the probe itself, we'd now have a big honking launching laser that would be of great help for moving stuff around the solar system as well...

  • (Score: 1, Insightful) by Anonymous Coward on Wednesday December 20, @12:24PM (6 children)

    by Anonymous Coward on Wednesday December 20, @12:24PM (#612262)

    I guess there is oil to be found on Alpha centauri... or the native inhabitants need freedom, but shouldn't we actually try to get our asses to Mars (or even a bit further) first?

    • (Score: 2) by Runaway1956 on Wednesday December 20, @12:29PM (2 children)

      by Runaway1956 (2926) Subscriber Badge on Wednesday December 20, @12:29PM (#612264) Journal

      We've already got cameras on Mars. Let us assume that it takes fifty years to get our asses there, after we plant some cameras and other hardware. This is great news! There may be people studyint the Centauri systems by 2200!!!

      Alright, so I'm being overly optimistic. Sue me.

      --
      #Hillarygropedme
      • (Score: 0) by Anonymous Coward on Wednesday December 20, @12:49PM

        by Anonymous Coward on Wednesday December 20, @12:49PM (#612269)

        Sue me.

        If I hurt my knuckles
        When I punch you in the face

        I'm gonna sue, sue
        Yes, I'm gonna sue
        Sue, sue, yeah that's what I'm gonna do

      • (Score: 3, Touché) by c0lo on Wednesday December 20, @12:57PM

        by c0lo (156) Subscriber Badge on Wednesday December 20, @12:57PM (#612270)

        This is great news! There may be people studyint the Centauri systems by 2200!!!

        Guess what? Those people will be librahls and will discover AGW has effects at least as far as Alpha Centauri.
        And this just to make you happy [soylentnews.org]

        (large trollish grin)

    • (Score: 3, Insightful) by takyon on Wednesday December 20, @02:51PM

      by takyon (881) <takyonNO@SPAMsoylentnews.org> on Wednesday December 20, @02:51PM (#612303) Journal

      Current plans by NASA would have humans in Mars orbit sometime in the 2030s. SpaceX plans would have humans walking on Mars by sometime after 2024 (add years of delay for realism). I am pretty sure we will get to Mars before 2069, and the 2069 mission would be an unmanned probe at best, or a Breakthrough Starshot gram-scale chipcraft at worst.

      --
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    • (Score: 2) by deadstick on Wednesday December 20, @03:24PM

      by deadstick (5110) on Wednesday December 20, @03:24PM (#612316)

      or the native inhabitants need freedom

      ...or Jesus.

    • (Score: 2) by JoeMerchant on Wednesday December 20, @03:42PM

      by JoeMerchant (3937) on Wednesday December 20, @03:42PM (#612329)

      Future plans are good, even if they extend beyond the next milestone.

  • (Score: 1) by ElizabethGreene on Wednesday December 20, @03:19PM (15 children)

    by ElizabethGreene (6748) on Wednesday December 20, @03:19PM (#612314)

    It's been 45 years since humans walked on another world; we've moved backwards, not forwards, since then.

    Unless there are terrorists there, it won't happen.

    • (Score: 2) by JoeMerchant on Wednesday December 20, @03:45PM

      by JoeMerchant (3937) on Wednesday December 20, @03:45PM (#612332)

      There could be terrorists there, and we need to go spread the word of Peace, Love and Smallpox to them before they get their act together and send probes to our planet.

    • (Score: 3, Insightful) by Immerman on Wednesday December 20, @04:15PM (13 children)

      by Immerman (3985) on Wednesday December 20, @04:15PM (#612344)

      Walking on another world was a publicity stunt - walking was about all we could do at the time, as our technology wasn't remotely ready to do anything useful there. *Especially* not for a price tag that would make it worth the opportunity cost. It was a statement of potential, made before we had the knowledge and technology to realize that potential, and there has been no compelling reason to repeat it.

      Meanwhile our space-relavent technology has advanced significantly since then. Ion drives. Closed-loop ecosystems. Reliable interplanetary "internet" infrastructure. Cheap, efficient solar panels. Light, high-capacity batteries. Safe, compact fission reactors (not *quite* there yet, but advancing rapidly). Cheap, lightweight, and energy efficient entertainment systems. VR may prove *extremely* useful for maintaining morale for the first people planning to live for decades in a small artificial environment on a desolate, airless world.

      We're rapidly approaching the point where we'll be able to actually do something more than just plant flags and voice pretty sentiments. The ISS made sense because it was close and relatively cheap to reach, while allowing us to experiment with microgravity and learn about the real day-to-day challenges of living in space, against the day where we were prepared to venture outside our magnetosphere. The moon would have been far more expensive while offering fewer benefits.

      But now the day is fast approaching where we can venture to other worlds and actually hope to live there and study and utilize them effectively. We've mapped the moon and Mars in impressive detail - we know where the valuable water and mineral deposits are located to give an outpost the best chance of being able to sustain itself and produce useful resources. We have the experience in maintaining artificial environments for long periods. We've confronted the biological challenges of microgravity, and have learned how to mitigate many of them, while having reason to hope that many of the rest will be mitigated by any substantial gravitational field.

      In short, we've made an *immense* amount of progress towards expanding into the solar system - we just haven't done any more flashy, expensive PR stunts. What would be the point? We already proved it was possible, nothing else will have that kind of emotional impact, and there's no sense going back in person until we're ready to actually do something useful.

      • (Score: 2) by HiThere on Wednesday December 20, @05:50PM (9 children)

        by HiThere (866) on Wednesday December 20, @05:50PM (#612405)

        Unfortunately, we've got a long way to go on the closed eco-system front. And it doesn't get anywhere near the attention it deserves. With a real closed eco-system (probably impossible) you could send mice anywhere in the galaxy...at, admittedly, and extremely slow speed. But it would need to maintain itself for aeons. Not feasible.

        A reasonably closed eco-system would allow human habitation of space, even though you need occasional space walks to scavenge an asteroid for gases and metals. The habitat would probably need to spin rather rapidly, and would need lots of mass for shielding, but it could be done. But you'd need to be able to fab your own solar cells, etc., as well as the other work of maintaining a civilization. This isolated scenario would probably require a population in at least the hundreds of thousands with current technologies. OTOH, with current technologies there's no requirement of isolation, as laser communication is cheap.

        Other technological developments would allow other scenarios, and I've totally left out living on other planets, as that has a larger number of unknowns. But in all the scenarios an improved "nearly closed" ecosystem would be a strong advantage.

        --
        Put not your faith in princes.
        • (Score: 2) by Immerman on Wednesday December 20, @07:01PM (8 children)

          by Immerman (3985) on Wednesday December 20, @07:01PM (#612451)

          True. We have a long way to go on truly closed ecosystems, but also no particular need for them when colonizing resource-rich planets or large asteroids. Mars is such a desirable target specifically because it's incredibly rich in easily accessible water, CO2, and nitrogen. That, some imported trace elements, and a big greenhouse will get you almost everything you need, ecology wise, and quite a bit in terms of industrial materials (nanocellulose for example is gas impermeable, transparent, and as strong as aluminum. Lots of potential there. And it can be made from plant waste using only thermomechanical processes, so no need to introduce toxic substances into the recycling stream.) And of course a planet has many other useful materials that become available as your available effort and industrial base expands.

          Technology wise - yes, there's likely going to be a long period of dependency on imports. However, there have been a lot of advances in cheap down-scalable manufacturing techniques. Solar panels and electronics that can be printed with a minimally-modified ink-jet printer for example. Heck, it wouldn't surprise me if Tesla's highly adaptable car-manufacturing plant weren't designed with an eye towards general-purpose offworld factories in the future - Musk clearly has a dream, and early colonies won't need a large quantity of production potential nearly as much as a wide *range* of it. The vast majority of current production goes to creating "disposable" goods - it could as easily go to creating far more durable and (cost-effective) goods instead, while radically reducing the amount of production required to maintain our standard of living (consider - your great-great-grandma's cast-iron skillet is probably still around somewhere, and is superior to pretty much anything made today.)

          And of course planets also provide gravity and radiation/meteorite shielding extremely cheaply - a few yards of sand or rock overhead do wonders in that regard.

          As for your mouse - the fact that expanding into space will undoubtedly (eventually) lead to excellent closed ecosystem management is one of the reasons I assume our species will eventually colonize other stars. Once you have a stable closed-loop ecology and industry base, all you need is enough nuclear fuel reserves to keep everything powered until you reach the next star, and the desire to get away from your neighbors. The first is unlikely to be a big problem, and the latter has been a rallying cry throughout human history - be it the immigrants escaping oppressive governments, or the oppressive governments trying to isolate themselves from destabilizing outside interference.

          • (Score: 2) by HiThere on Thursday December 21, @01:32AM (7 children)

            by HiThere (866) on Thursday December 21, @01:32AM (#612663)

            I disagree about the need. A "resource rich" asteroid won't be resource rich very long if you don't close your eco-system, and supplying things from outside gets quite expensive, even if they're close by.

            In the case of a planet things are a bit less clear, because most of the waste hangs around for a long time. Mars is still holding onto lots of CO2, even though it keeps getting ionized and the Oxygen heading off into space. But it used to have a lot more water, before the same thing happened to the water, except that Hydrogen escapes even without an energy boost (from the incoming radiation) so the angle at which the split happened was a lot less significant. It would still be a bad (i.e. short term) plan to terraform Mars without putting a lid on the atmosphere. I know it's probably doable, but it would be a massive waste for a short-term gain.

            That said, even for a planet running everything through the ecosystem once is a costly and stupid way to do things. Often the waste gets into places where you really don't want it, and a planet is finite. Large isn't the same thing as unlimited.

            --
            Put not your faith in princes.
            • (Score: 2) by Immerman on Thursday December 21, @02:43PM (6 children)

              by Immerman (3985) on Thursday December 21, @02:43PM (#612796)

              I agree - terraforming is a completely different problem. But if you're making a mostly-closed ecosystem on (or under) the surface of Mars then you'll have essentially unlimited resources with which to grow and replace incidental losses for a *very* long time. And obviously waste is one of the first things you want to eliminate - waste is just another name for raw materials you haven't recycled.

              Similarly even a mid-sized asteroid a few tens of miles across contains a LOT of raw materials - not limitless, but if you never intentionally throw anything away it should be quite capable of supporting a large city for centuries at least. And as recycling improves that number should grow towards infinity. Along with how to manage a closed ecosystem, how to effectively eliminate the creation of waste will likely be one of the biggest and most valuable lessons learned from space colonization - both will potentially be of immense benefit to Earth as well. Pretty much anything we can do in space, we can do here as well - it's less immediately necessary, but would drastically reduce our ecological footprint and help restore the health of this rare oasis of life.

              • (Score: 2) by HiThere on Thursday December 21, @06:44PM (5 children)

                by HiThere (866) on Thursday December 21, @06:44PM (#612888)

                Centuries is a short time for a population. Even the US is over 2 centuries old...closer to 3, really, since change of government doesn't signify in this context, and it's a new comer.

                Also the easily extracted resources tend to be used first, but that's your volatiles. Once those are gone, they're gone. So you need to start recycling from the start, and otherwise work to limit your losses. The idea is that all you need to import is energy (or, if you've got a good fusion engine, hydrogen). That's not going to happen, but it's important to get as close to that as possible. Importing things is expensive.

                --
                Put not your faith in princes.
                • (Score: 3, Interesting) by Immerman on Thursday December 21, @07:42PM (4 children)

                  by Immerman (3985) on Thursday December 21, @07:42PM (#612921)

                  I absolutely agree. But, centuries *is* a long time to work on perfecting your closed system to the point that you need minimal, if any, further imports to sustain yourself. And there's lots of other asteroids around, too small to justify colonizing, to scavenge for additional materials.

                  Besides, even a paltry 10 mile diameter asteroid is an equivalent volume of raw materials to all of California to a depth of 17 feet, or the entire US to a depth of 9 inches. That's a LOT of raw materials to support a single city. Even a big one. Especially if you're recycling essentially everything.

                  • (Score: 2) by takyon on Thursday December 21, @10:34PM (3 children)

                    by takyon (881) <takyonNO@SPAMsoylentnews.org> on Thursday December 21, @10:34PM (#612992) Journal

                    Ceres has 2.9% of 1g surface gravity, Vesta has about 2.5%, Pallas has about 2.2% (Vesta and Pallas are not rounded).

                    We should probably check those out as spots to colonize. Obviously 2-3% of Earth's gravity is not a lot, but it might be enough to counteract some health effects of microgravity.

                    Unfortunately, Pallas has a steeper orbital inclination that will make it more expensive to reach. Vesta orbits closer to the Sun than Ceres and doesn't have an internal ocean that we wouldn't want to contaminate. So while Ceres is probably in the top 10 rocks we want to colonize, Vesta might be a good first choice (for asteroids).

                    7 Iris (~213km) is down to 1.1% of 1g, and as for smaller 'roids, the largest near-Earth asteroid 1036 Ganymed [wikipedia.org] (~32 km) is at 0.09% of 1g which is negligible (it also has an aphelion of 4.0847 AU which may be undesirable).

                    --
                    [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
                    • (Score: 3, Interesting) by Immerman on Friday December 22, @01:58AM (2 children)

                      by Immerman (3985) on Friday December 22, @01:58AM (#613076)

                      It will be interesting to see if "centigravity" is substantially better for human health than microgravity. I suspect it will still be close enough to freefall that it won't be much better, other than for for keeping stuff where you left it.

                      On the other hand, I've thought it would be interesting to actually build a rotating space station within an asteroid - it can provide whatever range of artificial gravity is desired for residential quarters, while non-rotating modules would have all the benefits of microgravity. You could even tunnel all the way down to the center of mass for true freefall.

                      I do hope Ceres gets left alone long enough to study carefully - though I fear such a large mass of liquid water and assorted minerals might prove too tempting a target, especially since the first group to claim it will have a fare shot at staking a long-term claim to one of the most valuable pieces of real estate in the solar system - if they can defend it. At 2.77 million km of surface area it's only about the size of Argentina - the 8th largest country on Earth.

                      • (Score: 2) by takyon on Friday December 22, @02:32AM (1 child)

                        by takyon (881) <takyonNO@SPAMsoylentnews.org> on Friday December 22, @02:32AM (#613081) Journal

                        Hopefully, centigravity will get bodily fluids moving downwards generally, avoiding the upper body pooling seen on the ISS [wikipedia.org]:

                        The second effect of weightlessness takes place in human fluids. The body is made up of 60% water, much of it intra-vascular and inter-cellular. Within a few moments of entering a microgravity environment, fluid is immediately re-distributed to the upper body resulting in bulging neck veins, puffy face and sinus and nasal congestion which can last throughout the duration of the trip and is very much like the symptoms of the common cold. In space the autonomic reactions of the body to maintain blood pressure are not required and fluid is distributed more widely around the whole body. This results in a decrease in plasma volume of around 20%. These fluid shifts initiate a cascade of adaptive systemic effects that can be dangerous upon return to earth. Orthostatic intolerance results in astronauts returning to Earth after extended space missions being unable to stand unassisted for more than 10 minutes at a time without fainting. This is due in part to changes in the autonomic regulation of blood pressure and the loss of plasma volume. Although this effect becomes worse the longer the time spent in space, as yet all individuals have returned to normal within at most a few weeks of landing.

                        [...] Because weightlessness increases the amount of fluid in the upper part of the body, astronauts experience increased intracranial pressure. This appears to increase pressure on the backs of the eyeballs, affecting their shape and slightly crushing the optic nerve.

                        The small amount of gravity will let normal strength building exercises like weight lifting work, even if comically big weights are needed, perhaps fashioned directly out of asteroid rock.

                        Finally, it should cut down on motion sickness. Not sure if any was experienced by lunar astronauts.

                        The real action will be at the Moon and Mars for many decades - rather than Ceres. A subsurface ocean hasn't been ruled out on Mars:

                        https://news.nationalgeographic.com/news/2010/12/101214-mars-liquid-water-life-bacteria-human-mission-science-space/ [nationalgeographic.com]
                        https://www.universetoday.com/117502/meteoric-evidence-suggests-mars-may-have-a-subsurface-reservoir/ [universetoday.com]

                        We will have to live with the fact that people will be contaminating Mars while we are trying to study it. But it shouldn't be too bad as they will be constrained to a small area due to radiation concerns. Can they even wander 100 km away from home base without compromising their health?

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                        [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
                        • (Score: 3, Insightful) by Immerman on Friday December 22, @03:55PM

                          by Immerman (3985) on Friday December 22, @03:55PM (#613227)

                          It might help with biological issues - but I'm less confident. 10m/s^2 of acceleration is enough to easily overcome most incidental bodily forces. 0.1m/s^2 on the other hand could easily be dwarfed by normal turbulence and viscosity. Doesn't help you that much that your inner ear eventually settles down if you have to remain motionless for 10 minutes before it does so. You're also unlikely to get the regular micro-impacts from walking that seem to be important for maintaining skeletal strength - the energy to climb a single ladder step here would be enough to launch you a hundred feet in the air, and it would take five seconds for an initially stationary object to fall a single yard from rest - so moving around would probably be far more similar to doing so in freefall than under "real" gravity.

                          Ceres 0.03g *might* be enough to be somewhat useful - but is proportionally about as much lower than the moon's as the moon's is lower than Earth's, so I'm not sure that positive results on the Moon would be at all relevant.

                          As for exercising - I don't see that as any benefit at all. Those comically large weights will still have normal inertia, and won't care that you didn't *mean* to throw them through the ceiling and crush your upstairs neighbor to death. And they wouldn't seem to offer any major advantage over resistance bands, which operate completely independently of mass and gravity. If anything you'd have to develop whole new exercise regimes that exploit inertia rather than weight, since the weight would be essentially nonexistent in comparison.

      • (Score: 1) by ElizabethGreene on Thursday December 21, @11:25PM (2 children)

        by ElizabethGreene (6748) on Thursday December 21, @11:25PM (#613019)

        I've read that we've made dramatic improvements to our ability to live in Microgravity, but I don't see the detail behind it. Is the force resistant treadmill on the ISS dramatically better than the one they had on SpaceLab? Is there something else?

        The work on closed ecosystems has been fascinating, yes. I don't see the need to live in a closed system on the Moon or Mars though. There is literally an entire planet (or moon) of resources there. Here on Earth we have large crews that live for six months at a time without resupply in an enclosed open loop environment. e.g. Nuclear submarines. What, besides political will and heavy lift capacity, was the hold-up in implementing something like that on the Moon?

        • (Score: 2) by Immerman on Friday December 22, @01:20AM

          by Immerman (3985) on Friday December 22, @01:20AM (#613060)

          I agree - a large part of the appeal of colonizing a planet or asteroid, rather than building a free-floating habitat, is the abundance of raw materials.

          Nevertheless, collecting and processing most of those materials is likely to be a time- and energy-intensive process, such that recycling them as much as possible is liable to be extremely cost-effective. I.e. you try not to let things flow "out", but bring new materials "in" as quickly as you have the ability and demand for. Or to express it differently differently - your hypothetical steady-state situation is as close to closed as you can make it, but the reality is that you're constantly growing and adapting.

        • (Score: 2) by takyon on Friday December 22, @02:52AM

          by takyon (881) <takyonNO@SPAMsoylentnews.org> on Friday December 22, @02:52AM (#613087) Journal

          https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body [wikipedia.org]
          https://en.wikipedia.org/wiki/Space_medicine [wikipedia.org]

          A lot of what we have learned on the ISS has been bad news for human health in microgravity. Hopefully, long-term lunar gravity will be less of a challenge.

          We should aim to make these habitats waste-free and self-sustainable from the start, or at least as much as scientifically possible. Meaning the goal is no periodic resupply from Earth. They don't have to be closed ecosystems per se, but the things that we bring are resources that aren't likely to be reproduced so easily (3D-printing can only do so much). All the plastic should be biodegradable where possible, maybe made from the plants grown there and recycled by composting. There will be a desire to engage in industrial activity to produce useful products for the colonists. Miniaturization and other advances could help in this area. For example, miniature "chemputers" as well as genetically engineered microbes could produce a wide variety of drugs without the wasteful processes [theguardian.com] seen on Earth. You don't get the luxury of dumping waste and water outside, or venting gases into the atmosphere, since you need to recapture them all.

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  • (Score: 5, Funny) by wonkey_monkey on Wednesday December 20, @05:34PM (1 child)

    by wonkey_monkey (279) on Wednesday December 20, @05:34PM (#612391) Homepage

    the three-star Alpha Centauri system

    Aren't there any systems with better reviews we could go to instead?

    --
    systemd is Roko's Basilisk
  • (Score: 1, Interesting) by Anonymous Coward on Wednesday December 20, @06:54PM (1 child)

    by Anonymous Coward on Wednesday December 20, @06:54PM (#612447)

    there's a problem:
    "conventional socio-economic" technology, like reaction-mass engines, that require to mine a earth-bound resource, or a part of the earth itself and then eject or dump it into some general direction of outerspace is not going to cut it (for the distance).

    one could re-phrase it as profit taking by (very) slowly reversing the formation of the earth, that is the accumulation of dust and debris into a planet.

    i believe there are gigantic forces to be harnessed from nature and it doesn't require a huge machine and gazillion of people working together.
    the problem is, what happens during the transition time, where this technology becomes common knowledge but with no plan (what to do with this new discovered energy) and the human mind still stuck in the old way of thinking?

    it would be like a regular sized ant that can now lift your whole house. what would the ants do?
    would they throw each other onto other planets (and solar-systems) or would they not care and just start a ant-world-war with everything else, including whatever supports ant-life to becoming collateral damage?

    • (Score: 3, Interesting) by c0lo on Wednesday December 20, @07:49PM

      by c0lo (156) Subscriber Badge on Wednesday December 20, @07:49PM (#612482)

      "conventional socio-economic" technology, like reaction-mass engines, that require to mine a earth-bound resource, or a part of the earth itself and then eject or dump it into some general direction of outerspace is not going to cut it (for the distance).

      Theoretically, a single ejected proton would be enough to move the entire Earth in another star system - if you could accelerate the proton enough.
      You know that m = m0/sqrt(1-v2/c2) guarantees that the proton will have the mass of Earth if its speed is close enough to c.

  • (Score: 0) by Anonymous Coward on Wednesday December 20, @08:41PM (2 children)

    by Anonymous Coward on Wednesday December 20, @08:41PM (#612527)

    Why wait until 2069? Warp drive is invented in 2063.

  • (Score: 2, Interesting) by careysub on Thursday December 21, @04:38AM

    by careysub (6028) on Thursday December 21, @04:38AM (#612700)

    This was very fishy, since the notion of doing this any time in this century is ridiculous, and NASA is really not in the habit of floating wildly improbable ideas half a century out.

    Tracing the story back to the original in the New Scientist confirms this is not the real story at all.

    Here is the real scoop from the New Scientist article:

    “It’s very nebulous,” says Anthony Freeman at JPL, who presented the mission concept at the 2017 American Geophysical Union conference in New Orleans, Louisiana, on 12 December.

    The impetus came from a 2016 US funding bill telling NASA to study interstellar travel that could reach at least 10 per cent of the speed of light by 2069.

    So, something was put in a funding bill requiring they "study" the idea, which dictated the time and the performance, so a JPL scientist presented a vague concept at a conference about it.

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