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Space Transportation Science

Electric Rockets Set To Transform Space Flight 114

Posted by Soulskill
from the flying-to-the-future-at-full-impulse dept.
An anonymous reader sends this quote from an article at Txchnologist: "The spectacle of a booster rocket lifting off a launch pad atop a mass of brilliant flames and billowing smoke is an iconic image of the Space Age. Such powerful chemical rockets are needed to break the bonds of Earth's gravity and send spacecraft into orbit. But once a vehicle has progressed beyond low-earth orbit chemical rockets are not necessarily the best way to get around outer space. That's because chemical propulsion systems require such large quantities of fuel to generate high speeds, there is little room for payload. As a result rocket scientists are increasingly turning to electric rockets, which accelerate propellants out the back end using solar-powered electromagnetic fields rather than chemical reactions. The electric rockets use so much less propellant that the entire spacecraft can be much more compact, which enables them to scale down the original launch boosters."
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Electric Rockets Set To Transform Space Flight

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  • by Spliffster (755587) on Tuesday February 21, 2012 @03:48PM (#39115859) Homepage Journal

    Tesla would love this shit!

  • by Anonymous Coward

    Is there even enough material on Earth to produce a power cord long enough to propel a rocket to the moon!?

  • Aren't you going to need one humongous extension cord?

  • Ion Drive isn't new (Score:5, Informative)

    by Anonymous Coward on Tuesday February 21, 2012 @03:54PM (#39115965)

    This is old technology and the benefits of this have already been realized in many satellites. There is literature going back well over a decade documenting the trade space.

    • by Anonymous Coward on Tuesday February 21, 2012 @04:15PM (#39116301)

      More like decades; quoted from Wikipedia,

      The official father of the concept of electric propulsion is Konstantin Tsiolkovsky as he is the first to publish mention of the idea in 1911. However, the first documented instance where the possibility of electric propulsion is considered is found in Robert H. Goddard's handwritten notebook in an entry dated 6 September 1906. The first experiments with ion thrusters were carried out by Goddard at Clark University from 1916–1917.The technique was recommended for near-vacuum conditions at high altitude, but thrust was demonstrated with ionized air streams at atmospheric pressure. The idea appeared again in Hermann Oberth's "Wege zur Raumschiffahrt” (Ways to Spaceflight), published in 1923, where he explained his thoughts on the mass savings of electric propulsion, predicted its use in spacecraft propulsion and attitude control, and advocated electrostatic acceleration of charged gases.

      A working ion thruster was built by Harold R. Kaufman in 1959 at the NASA Glenn Research Center facilities. It was similar to the general design of a gridded electrostatic ion thruster with mercury as its fuel. Suborbital tests of the engine followed during the 1960s and in 1964 the engine was sent into a suborbital flight aboard the Space Electric Rocket Test 1 (SERT 1). It successfully operated for the planned 31 minutes before falling back to Earth.

      • by ackthpt (218170)

        Meanwhile I continue to listen to X Minus One and Dimension X radio shows and cannot believe any of this. Cleary it's all a hoax.

        and also rocket jocks will be quarrelsome people with the attitudes of disgruntled mechanics and having flight or engineering credentials is a preposterous notion.

    • by sycodon (149926)

      Somebody do the math.

      If you had a 100 megawatt reactor to play with on a ship, what kinds of velocity could you achieve?

      Just for giggles, say it was one of the Shuttles and that you could>/i> fit a 100 megawatt reactor in the cargo bay.

      • by tp1024 (2409684) on Tuesday February 21, 2012 @05:39PM (#39117303)
        The watt count doesn't matter. It's exhaust velocity (more means more energy use, no matter what technology) of the engine and the total amount of energy carried by the reactor (more energy means more mass, means less speed). 0.1-1% of the speed of light should easily be possible, but I haven't done the math to the point of calculating multiple stages, optimizing the energy budget with respect to the trade-off between exhaust velocity and energy consumption and so on and so forth.

        Hydrogen-Oxygen fuel has an exhaust velocity of about 4500m/s for a final speed on the order of 20km/s with multiple stages (for any significant payload). Simple ion engines can reach 30,000m/s, but final speeds will be less than expected, as the empty mass of the stages is higher. Something on the order of 100km/s with 2-3 stages should be possible. (Let's say 12,000 years to Alpha Centauri.) More sophisticated engines can reach up to 200,000m/s in exhaust velocity (2000 years to Alpha Centauri), but somewhere the energy limitations will kick in and I don't know whether before or after that point. (That's when the Uranium/Plutonium makes up a very significant part of the deadweight - even if you throw some of it over board in the process.)

        Just build some of space ships and a couple of pyramids in a desert to remind people they are on their way.
        • by lgw (121541)

          That looks very optimistic - do your number include stopping at Alpha Centauri, or jjust waving as you fly by at high speed? (And IIRC the total stored energy needed is immense, even at 200 km/s).

          • by rednip (186217)

            do your number include stopping at Alpha Centauri, or jjust waving as you fly by at high speed?

            Why wave, when you can just deceleration into it? Only four some odd years later we could tell what it was made of by just using a telescope. After all, it'll be kind of a useless trip unless you had some way of returning data.

            • by lgw (121541)

              It takes far more energy to stop than to fly by - which is why those numbers looked so optimistic. Interstellar travel on a human time scale requires just a staggeringly huge energy budget, far beyond what our species is capable of right now (as in, too many years of all the energy we currently produce on Earth, somehow stored as fuel).

          • by tp1024 (2409684) on Tuesday February 21, 2012 @06:52PM (#39118161)
            Nope, just getting there. Think of it as a beeping monument in the sky.

            A beeping monument with telescopes. The main justification would need to be astrometry, which you could do a hell of a lot better if you had a good telescope several hundred or thousand AU away from earth. Currently, we're doing all our triangulation with a 2AU long base (twice the distance earth-sun). Using the same 29cm telescope as Hipparcos [wikipedia.org], we could easily get 1000 times more accurate ranging data within mere decades.

            It would be a revolution. True trigonometric measurements all the way to the other end of the galaxy, even the nearest neighboring galaxies, instead of the current guesswork based on guessing how bright a certain star is and thus how far it would need to be away in order to appear as bright as it does.
          • by tp1024 (2409684)
            Just to add one more thing: The kinetic energy of a hypothetical 10t final stage is 2e14J, equivalent to complete fissioning of 3kg Uranium (of course, efficiency will not be 100%, more likely 0.1-1%).
        • by symbolset (646467) *
          The ion engines will get better over time. And there are quite a few problems with your math.
        • by Rich0 (548339)

          The watt count doesn't matter.

          Not for top speed or specific impulse, but it certainly matters for force/acceleration. More watts means more particles of propellant being accelerated per unit time, which means more force. In general ion engines are low-power but high-impluse. That means they have low accelerations, but are much more efficient since you need less fuel (and fuel is dead weight when accelerating). If you could have a relatively light nuclear reactor that could provide high power, then you'd have the best of both worlds

    • it was never incorporated into a tug. It has always been part of sats. With this approach, you will have a sat that can plug into a tug. The tug can be chemical, electric, or nuke (or combinations thereof). By separating the engine/fuel from the payload, it will mean that all we have to do is put something into LEO and then use a tug to move items around. A cargo load or a sat, can be done via electric. A human load, might get chemical to move up and around quickly.
    • Satellites and starfighters. Twin Ion Engine Fighters have existed since 1977.

  • Ahh, the future (Score:5, Interesting)

    by squidflakes (905524) on Tuesday February 21, 2012 @03:55PM (#39115997) Homepage

    The best part about living where I live is that they are building VASMIR engines down the street. It would be a long walk, but I could still walk to a freaking starship drive factory.

  • We are going to get shiny metallic space suits next.
    Robots that flails its arms screaming "Danger Will Robinson Danger !"
    This is great stuff we are back to ION propulsion which is kind of cool. Remember the spaceships that sail like Solar wind and stuff?
    That would be cool too. Perhaps next we can actually get someone to care and fund this stuff and some of it will end up actually mattering in the long run.
    • by Tumbleweed (3706) * on Tuesday February 21, 2012 @05:08PM (#39116979)

      We are going to get shiny metallic space suits next.
      Robots that flails its arms screaming "Danger Will Robinson Danger !"
      This is great stuff we are back to ION propulsion which is kind of cool. Remember the spaceships that sail like Solar wind and stuff?
      That would be cool too. Perhaps next we can actually get someone to care and fund this stuff and some of it will end up actually mattering in the long run.

      Of all the things in your posting, the last sentence is by far the least-likely. :(

  • by Anonymous Coward

    Well, it's still a lot of fluff. Yes, you can create an electric propulsion system that over a long period of time can absorb enough energy to move an object. But should the object need to change direction these drives may take weeks to change a ships direction by 10-20 degrees. If you are thinking of sending people up in a ship that can't has such limited mobility you might as well give the passengers their last rites before lift off.

    For each and every action there is an opposite reaction. While jettis

    • by stjobe (78285) on Tuesday February 21, 2012 @04:52PM (#39116779) Homepage

      Yeah. Dawn's ion engines (linked to in TFS) have a very high ISP (3100s), but an equally low thrust (90 mN).
      As a comparison, the F-1 engines on the Saturn V Stage I-C had pretty low ISP (about 250s), but a massive 34 MN of thrust.

      Basically you can have high ISP (electrical) or high thrust (chemical), but not both.

      Unless you go VASIMR, of course, and we're not quite there yet.

  • by iliketrash (624051) on Tuesday February 21, 2012 @04:12PM (#39116257)

    This piece piques one of my pet peeves, the confusion between scientists and engineers. Scientists do not build rockets--engineers build rockets. Even if a person trained in, say, physics, is designing a rocket, that person is effectively acting as an engineer.

    I object to attempts to glorify certain kinds of engineers by calling them scientists. There is no such need to glorify engineers--they are glorious in their own right. Calling them scientists is a slap in the face and an insult.

    Engineering and science could hardly be different. Engineers put things together; scientists take things apart.

    • You're right, calling those lowly aerospace guys "rocket scientists" is an affront to real scientists everywhere.

      -Mike Q. Hunt, computer scientist
      Java, C#, Ruby project leader
    • by Anonymous Coward
      Yeah, No. In practice engineering and science go hand in hand. "Rocket scientists" or aerospace engineers indeed had/have to learn and understand new physics and create knowledge with the scientific method to engineer/build new devices. Scientists in the lab frequently have to apply their science and engineer measurement tools and facilities to approach new science. A PhD dissertation in mechanical engineering a scientific and an engineering contribution.
    • by Whatanut (203397)

      Of course, I would argue that engineers don't typically build rockets either. They design them. Then some factory worker builds it...

    • by ceoyoyo (59147) on Tuesday February 21, 2012 @05:28PM (#39117183)

      If you're building new drives to experiment with, you're a scientist. If you're following established principles to build a drive then you're an engineer.

      The distinction isn't nearly as clear as you imply, and isn't based on your criteria.

      I have degrees in oth science and engineering. Normally I do science with a bit of engineering, figuring out how to do new things. Sometimes I do engineering with a smattering of science figuring out how to do those new things out in the field.

    • by BryanL (93656)

      Is that you Sheldon Cooper?

  • by wisebabo (638845) on Tuesday February 21, 2012 @04:12PM (#39116261) Journal

    I've actually been following ion powered (and all space flight) for a long time now and have wondered that ever since Deep Space 1 (no, not a TV series) "proved" the technology worked (that was one of its main jobs, it was a technology demonstrator) they didn't use ion engines on the space craft that used RTGs.

    In particular New Horizons has travelled billions of miles coasting to Pluto, 99% of the time in hibernation despite the fact that its plutonium powered RTG is generating electricity whether used or not (it's not a reactor, it is always "on"). Considering the distance it has to travel, an ion drive could've really sped things up (or conversely allowed it to brake, and orbit Pluto!). Cassini might not have been such a good choice because maybe having the drive on doesn't allow good scientific observations (Cassini doesn't have its instruments on a scan tilt platform) and anyway the many delta - V changes might have required more thrust than the very weak ion drives can provide.

    Actually, maybe ANY probe headed further than the moon or mars would find this useful. Juno, the Jupiter orbiter had huge solar panels which, during the cruise phase could have powered a decent ion engine. Messenger, the Mercury orbiter, although not going "far", had a huge delta-V requirement and had access to plenty of solar power.

    Oh well, at least more and more probes like DAWN use this. I would presume when we return to the outer planets with any really ambitious probes (Europa lander/sub, Titan balloon/boat) they'll use this.

    Someday, when we talk about sample return missions and the delta-V requirements at least double (and the fuel requirements go up geoemetrically!), ion drives (or their derivatives like the Vasimir drive) will be essential.

    • How about this; NASA should equip the upcoming 8 BILLION DOLLAR JWST with an ion drive. And put a little extra xenon fuel in the tank!

      That way, if something should go wrong with the 8 BILLION DOLLAR spacecraft, there's at least a small chance we'd be able to bring it back to LEO where it could be fixed (like Hubble). We won't have man-rated capability to fix it where it is for probably for another decade. :(

      Actually since it's probably way too late to add an ion drive and fuel tank to this thing, why not

    • I've actually been following ion powered (and all space flight) for a long time now and have wondered that ever since Deep Space 1 (no, not a TV series) "proved" the technology worked (that was one of its main jobs, it was a technology demonstrator) they didn't use ion engines on the space craft that used RTGs.

      Because ion drives are heavy, and their fuel tanks are heavier - and the wiring and controls are complex. So, weight to take away from payload, and more things to break, for very little return. What

  • by recharged95 (782975) on Tuesday February 21, 2012 @04:12PM (#39116267) Journal

    The HS601 and its XIPS system [daviddarling.info] is technically electric since it is an Ion propulsive device. The above FTA is more about plasma thrust, but again all these concepts have been around for 50yrs: it's well known higher specific impulse == more acceleration for space flight == a better engine (and ions have more impulse than anything chemical)...

  • by Loadmaster (720754) on Tuesday February 21, 2012 @04:13PM (#39116275) Homepage

    Turns out I was wrong. I made myself sad. Here's the technology that might actually transform space flight.

    http://www.adastrarocket.com/aarc/ [adastrarocket.com]
    http://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket [wikipedia.org]

    The guy who invented it is an ex-Astronaut and VASIMR (or its tech underpinnings) was his PhD thesis at MIT for Applied Plasma Physics. I guess what I'm saying is he isn't a crank.

    • by Spy Handler (822350) on Tuesday February 21, 2012 @04:37PM (#39116601) Homepage Journal

      I guess what I'm saying is he isn't a crank.

      Actually, according to Rob Zubrin of Mars Society, he is one. The technology itself isn't a crank, it's real, but his claims (going to Mars in 39 days) and the big bucks he's soliciting are quite cranky.

      To do what he's claiming, you would need to hook up the VASIMIR to a huge nuclear reactor. How do you get that reactor into orbit? You can't, not without a Nova type rocket bigger than a Saturn V. But if you had such a rocket, you could just blast off to Mars the old-fashioned way.

      His other proposal is coupling a fusion reactor (which should be lighter than an equivalent fission one) to the VASIMIR. Well as we all know, fusion is always 20 years in the future.

      • Re: (Score:3, Interesting)

        by WindBourne (631190)
        Getting the reactor into space is NOT a big deal. The issue with VASIMR is that you need LOADS of electricity. As such, it would weigh so much that VASIMR would not be able to push it around. And that is a reactor without ANY shielding. The issue is that the radiator to dump heat would weigh a great deal.

        It is far more likely that we will send a team on a one-way mission to Mars and keep them there for 10-20 years, while we re-develop NERVA. NERVA makes far more sense for moving around the solar system t
      • I guess what I'm saying is he isn't a crank.

        Actually, according to Rob Zubrin of Mars Society, he is one.

        And to be considered a crank by Robert Zubrin (a World Class Crank himself), you really have to be whack-a-doodle.

  • Space Age 2: Electric Boogaloo.

    • by youn (1516637)

      Space age with a squirrel in spacesuit looking going after the space nut, causing mischief throughout... now that sounds like a fun sequel to ice age :)

  • SEP has been in regular use for over a decade now...first EP-powered deep space mission was in 1998 (Deep Space 1), and just about every Earth-orbiting satellite relies on EP.
    • I agree that it is old new, but most Earth-orbiting satellites DO NOT have anything like electrical propulsion.

  • I built an ion rocket in 6th grade that was suspended from a string, and would increase the height to which it swung every time the high-voltage transformer was pulsed. Deep Space One had an electric rocket. These have been around awhile.

  • by Oswald McWeany (2428506) on Tuesday February 21, 2012 @04:27PM (#39116483)

    Stardate 45280.4

    My crew and I have just left Earth's orbit, it took a mere 15 minutes to accelerate enough to reach escape velocity. Unfortunately, we ran out of batteries the moment we passed the moon and are now waiting for the Vulcans to come rescue us. Unfortunately, there are no electric charding stations out past the great-divide so we will have to be taken back earth where our crew will double the number of lithium ion batteries.

    • by mjwx (966435)

      Stardate 45280.4

      My crew and I have just left Earth's orbit, it took a mere 15 minutes to accelerate enough to reach escape velocity. Unfortunately, we ran out of batteries the moment we passed the moon and are now waiting for the Vulcans to come rescue us. Unfortunately, there are no electric charding stations out past the great-divide so we will have to be taken back earth where our crew will double the number of lithium ion batteries.

      This would never have happened if they used dilithium-ion batteries.

  • by Trapezium Artist (919330) on Tuesday February 21, 2012 @04:28PM (#39116495)

    I've long since given up on there being any semblance of proper research done in such articles, particularly when a nod might have to be given to anyone outside the US.

    I'm no expert in the history of solar electric ion propulsion systems, but believe that NASA's Deep Space-1 mission in 1998 was (I think) the first to use SEP as its primary post-launch propulsion, as several subsequent NASA missions, including Dawn, as discussed in the article.

    However, several European Space Agency missions have also used similar systems, including the ARTEMIS satellite in 2001 to get itself to geostationary orbit, the SMART-1 mission to the Moon (launched 2003, ended in a deliberate crash onto the Moon in 2006), the GOCE gravity-mapping mission, and the BepiColombo mission to Mercury (due for launch in 3 years) will be using one. The Japanese Hayabusa-1 asteroid sample return mission also used one.

    Just trying to set the record at least a little straighter ...

  • by WindBourne (631190) on Tuesday February 21, 2012 @04:31PM (#39116539) Journal
    A better approach is the Electrodynamic tether [wikipedia.org]. Basically, create a linear motor against the earth's mangnetic field. This can only be used in orbit, BUT, there would be no fuel.
  • All the electric propulsion methods have thrust in the order of Newtons. That's usually enough for interplanetary cruises but doesn't solve the most important problem - putting things into the orbit.

    • by Dasher42 (514179)

      Wouldn't balloons or maglev catapults be good alternatives for first stage boosters? Both would feature considerably less energy input.

      • by Cyberax (705495)

        Nope. Maglev catapults need to be of stupendous size to be useful and balloons are not useful at all.

  • by WindBourne (631190) on Tuesday February 21, 2012 @04:42PM (#39116675) Journal
    This is not about creating an electric engine. It is about creating a TUG or Tractor that is electric powered. With such a device, it would be cheap to put a load into GEO or to EML1 cheaply.
  • I mean cause everyone knows weight is a factor when lifting objects into orbit, so no doubt batteries to power the engines wouldn't be a factor.
    • by buback (144189)

      Electric engines would either use solar panels or RTG for power, not batteries. Hell, they'd use fuel cells before they used batteries. any of these options are much much lighter than normal fuel, but even if they were equal for certain sized payloads, electric engines are much more efficient, so as payload mass increases, fuel mass scales at a much smaller rate.

  • This is about Ion drives right? Sounds like it.. There are probes/satellites out there that have ion drives - they were conceived of in something like the 1960s. Not exactly news, but indeed it is awesome. Though Ion drives don't produce the necessary thrust to be used for atomopheric travel. But one can hope.
  • " which enables them to scale down the original launch boosters."

    Why scale them down ?

    Why not use the biggest boosters and use the extra capability to bring more propellant into space

    Even if you just dropped it in a parking orbit till it was needed for a different mission

  • It's been around since the year Tet. NASA [nasa.gov] have been playing with the idea for years; they have even deployed it [nasa.gov]. In 1968 a certain TV show [memory-alpha.org] used it as a plot device. Said show reused the plot device in several subsequent episodes and at least one movie.

    The problem with EIP is that it produces such a small amount of thrust (although large compared with the amount of propellant it uses, it's still less thrust than you get from a can of hairspray), a human in a capsule wouldn't even feel the pressure in the sma

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