Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Monday October 16 2017, @06:32AM   Printer-friendly [Skip to comment(s)]
from the to-infinity-and-beyond! dept.

A Hall-effect thruster designed by University of Michigan researchers, NASA, and the U.S. Air Force has achieved a maximum thrust of 5.4 Newtons. The "X3" thruster uses three channels of plasma instead of a single channel like most Hall thrusters. It is designed to operate at 200 kW but has been tested at a range of 5 kW to 102 kW so far:

A thruster that's being developed for a future NASA mission to Mars broke several records during recent tests, suggesting that the technology is on track to take humans to the Red Planet within the next 20 years, project team members said.

The X3 thruster, which was designed by researchers at the University of Michigan in cooperation with NASA and the U.S. Air Force, is a Hall thruster — a system that propels spacecraft by accelerating a stream of electrically charged atoms, known as ions. In the recent demonstration conducted at NASA's Glenn Research Center in Ohio, the X3 broke records for the maximum power output, thrust and operating current achieved by a Hall thruster to date, according to the research team at the University of Michigan and representatives from NASA.

"We have shown that X3 can operate at over 100 kW of power," said Alec Gallimore, who is leading the project, in an interview with Space.com. "It operated at a huge range of power from 5 kW to 102 kW, with electrical current of up to 260 amperes. It generated 5.4 Newtons of thrust, which is the highest level of thrust achieved by any plasma thruster to date," added Gallimore, who is dean of engineering at the University of Michigan. The previous record was 3.3 Newtons, according to the school.

A manned Mars mission could require a thruster capable of operating at 500 kW-1 MW, if not more.

Previously: Researchers Improve the Design of Cylindrical Shaped Hall Thrusters


Original Submission

Related Stories

Researchers Improve the Design of Cylindrical Shaped Hall Thrusters 8 comments

Researchers have improved the design of Cylindrical shaped Hall thrusters (CHTs), a type of ion drive used in spacecraft:

Researchers from the Harbin Institute of Technology in China have created a new inlet design for Cylindrical shaped Hall thrusters (CHTs) that may significantly increase the thrust and allows spaceships to travel greater distances.

[...] The researchers injected the propellant into the cylindrical chamber of the thruster by a number of nozzles that usually point straight in, toward the center of the cylinder. The angle of the inlet nozzles changed slightly, sending the propellant into a rapid circular motion and creating a vortex in the channel.

They then simulated the motion of the plasma in the channel for both nozzle angles using modeling and analysis software called COMSOL that uses a finite element approach to modeling molecular flow.

This resulted in a gas density near the periphery of the channel is higher when the nozzles are tilted and the thruster is run in vortex mode.

According to the study, the vortex inlet increases the propellant utilization of the thruster by 3.12 percent to 8.81 percent, thrust by 1.1 percent to 53.5 percent, specific impulse by 1.1 percent to 53.5 percent, thrust-to-power ratio by 10 percent to 63 percent and anode efficiency by 1.6 percent to 7.3 percent, greatly improving the thruster performance.

More likely to be deployed than EmDrive.

Effect of vortex inlet mode on low-power cylindrical Hall thruster (open, DOI: 10.1063/1.4986007) (DX)


Original Submission

This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
(1)
  • (Score: 2) by Runaway1956 on Monday October 16 2017, @08:06AM (7 children)

    by Runaway1956 (2926) Subscriber Badge on Monday October 16 2017, @08:06AM (#582925) Homepage Journal

    "A Mars mission could require a thruster capable of operating at 500 kW-1 MW, if not more."

    It's not really ready for interplanetary travel yet. Maybe, given time and further research, it will suffice for manned missions to the planets. But, it still looks pretty good for rock hoppers and miners. Put your manned mining ship into, or near, a swarm of small to medium sized rocks, and send your drones out to gather stuff up. And, nothing says these engines won't suffice for interplanetary probes and robots.

    Anything that reduces the requirement for reaction mass is good. It's terribly inefficient to drag around a hundred tons (or more) of reaction mass for each ton of payload.

    --
    There is a supply side shortage of pronouns. You will take whatever you are offered.
    • (Score: 2) by takyon on Monday October 16 2017, @08:13AM

      by takyon (881) <takyonNO@SPAMsoylentnews.org> on Monday October 16 2017, @08:13AM (#582927) Journal

      Meant to say MANNED Mars mission. Relevant text:

      Commercially available Hall thrusters are not nearly powerful enough to propel a crewed Mars spacecraft, he added.

      "What we would need for human exploration is a system that can process something like 500,000 watts (500 kW), or even a million watts or more," Gallimore said. "That's something like 20, 30 or even 40 times the power of conventional ."

      That's where the X3 comes in. Gallimore and his team are addressing the power problem by making the thruster bigger than these other systems and by developing a design that addresses one of the technology's shortcomings.

      "We figured out that instead of having one channel of plasma, where the plasma generated is exhausted from the thruster and produces thrust, we would have multiple channels in the same thruster," Gallimore said. "We call it a nested channel."

      According to Gallimore, using three channels allowed the engineers to make X3 much smaller and more compact than an equivalent single channel Hall thruster would have to be.

      --
      [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 2) by c0lo on Monday October 16 2017, @10:21AM (5 children)

      by c0lo (156) on Monday October 16 2017, @10:21AM (#582946) Journal

      Anything that reduces the requirement for reaction mass is good.

      And replaces it with what?
      1 ton of plutonium in a 10 tons enclosure to generate 1MW for 50 wimpy Newtons of thrust (the weight of 5kg in Earth gravity)?

      I think I prefer to wait for takyo... sorry, for tachion propulsion.

      --
      https://www.youtube.com/watch?v=aoFiw2jMy-0
      • (Score: 2) by Runaway1956 on Monday October 16 2017, @11:13AM (4 children)

        by Runaway1956 (2926) Subscriber Badge on Monday October 16 2017, @11:13AM (#582959) Homepage Journal

        You need electricity to make the hall effect work. We know of several ways to produce electricity, so fissionable or fusionable materials may not be necessary. Solar panels, today, probably aren't efficient enough to do the job, except in very small applications. Or, maybe they are efficient enough. Someone who understands the math better than I might want to weigh in. Suppose we eliminate ten tons of reaction mass, replace that with three tons of ionizing mass, plus 1/4 ton of solar panel which doubles as solar sail? No radioactive material involved, no need for shielding, so we have a net gain.

        Lest I sound overly enthusiastic, I realize that what we have right now just isn't going to do the job. But, that's what research is all about. First generation X3 looks more promising than it's predecessors, so give them a little more time. MAYBE they'll have something that can move people from here to there in a reasonable time. Maybe five years, maybe ten, maybe never. But, it looks promising. But, whether it moves people over interplanetary distances, it seems obvious these things can be useful in other applications. And, we're back to the drones and robots, operating from a manned mining ship.

        --
        There is a supply side shortage of pronouns. You will take whatever you are offered.
        • (Score: 2) by c0lo on Monday October 16 2017, @01:33PM

          by c0lo (156) on Monday October 16 2017, @01:33PM (#582981) Journal

          And, we're back to the drones and robots, operating from a manned mining ship.

          Once you've got there, plenty of reaction mass if you have energy to refine and use the refuse as propulsion mass.
          Getting there with enough energy to mine asteroids within a reasonable time seems to be yet a(n economic) problem.

          I suspect using the Moon as a launching base for asteroid mining makes more sense in the present state of technology (given that the science for propulsion is no longer cutting edge - that is, unless the em-drive actually turns out to work).

          --
          https://www.youtube.com/watch?v=aoFiw2jMy-0
        • (Score: 2) by Fluffeh on Monday October 16 2017, @10:39PM (2 children)

          by Fluffeh (954) Subscriber Badge on Monday October 16 2017, @10:39PM (#583199) Journal

          Someone who understands the math better than I might want to weigh in.

          It's not so much math as physics rather. Most propulsion systems require the propellant to be accelerated by the "engine" as such to push it out either in volume (normal chemical rockets that can spend all the TONS of fuel in a few minutes) or to push out a small volume at incredible speeds such as an Ion drive - to generate thrust and move the craft.

          These Hall Effect drives are the latter and work by making a decent magnetic field, then expelling a tiny amount of gas and stripping the electrons from it (making it magnetically changed). As the gas is then repulsed by the magnetic field, it is pushed away from the craft at 20-50 kilometers (12-30 miles) per second and in doing so, exacts an equal opposite pressure on the engine which is fixed to the craft. Due to the propellant moving at such incredible speeds, the thrust efficiency compared to the fuel needed is fantastic. The Deep Space 1 [wikipedia.org] spacecraft was accelerated to 4.3 kilometers (2.7 miles) per second using under 75 kilograms (165 pounds) of xenon gas propellant.

          The problem with Ion drives however was being able to effectively scale up the thrust generated. In a normal rocket, you can have a small system that uses a fuel, but you can just make it bigger to get scaled thrust. With Ion Drives, it was pretty easy (relatively speaking) to make a small drive with a very small thrust, but you couldn't just make everything bigger to get more thrust in the same way you could with a standard chemical propellant. This is exciting as it is moving forward in scaling up the system. It is good steps in the right direction!

          • (Score: 0) by Anonymous Coward on Monday October 16 2017, @11:06PM (1 child)

            by Anonymous Coward on Monday October 16 2017, @11:06PM (#583207)

            Correction to your physics: the ion propulsion system works on ELECTRICALLY CHARGED particles (ions) being accelerated by an ELECTRIC field. Not magnetic.

  • (Score: 0) by Anonymous Coward on Monday October 16 2017, @09:45AM (7 children)

    by Anonymous Coward on Monday October 16 2017, @09:45AM (#582939)

    "You can think of electric propulsion as having 10 times the miles per gallon compared to chemical propulsion," Gallimore told Space.com.

    Really? Back to this ion engine, isn't the xenon used for propellent about 10 times the price of petroleum?

    • (Score: 0) by Anonymous Coward on Monday October 16 2017, @09:55AM (3 children)

      by Anonymous Coward on Monday October 16 2017, @09:55AM (#582940)

      Petroleum? I didn't realize that the weight and potential energy of petroleum made it an effective fuel for spacecraft.

      • (Score: 0) by Anonymous Coward on Monday October 16 2017, @10:11AM (1 child)

        by Anonymous Coward on Monday October 16 2017, @10:11AM (#582942)

        Petroleum? I didn't realize that the weight and potential energy of petroleum made it an effective fuel for spacecraft.

        Nor does the weight and environmental cost of batteries currently make electrics an effective replacement for petroleum powered vehicles here on Earth. [bloomberg.com] We are all betting that the technology of electric vehicles will improve, I doubt that the economic efficiencies of ion thrusters will unless they can work with another gas for propellant.

        • (Score: 0) by Anonymous Coward on Monday October 16 2017, @01:14PM

          by Anonymous Coward on Monday October 16 2017, @01:14PM (#582973)

          False equivalency.

      • (Score: 0) by Anonymous Coward on Monday October 16 2017, @04:06PM

        by Anonymous Coward on Monday October 16 2017, @04:06PM (#583031)

        He's clearly a 20th century AC. We've long moved on from internal combustion engine-based rockets.

    • (Score: 3, Interesting) by takyon on Monday October 16 2017, @11:10AM (1 child)

      by takyon (881) <takyonNO@SPAMsoylentnews.org> on Monday October 16 2017, @11:10AM (#582958) Journal

      https://en.wikipedia.org/wiki/Iodine_Satellite [wikipedia.org]

      A key advantage to using iodine as a propellant is that it provides a high density times specific impulse,[5][2] it is three times as fuel efficient as the commonly flown xenon,[6] it may be stored in the tank as an unpressurized solid, and it is not a hazardous propellant. 1U with 5 kg of iodine on a 12U vehicle can provide a change of velocity of 4 km/s ΔV, perform a 20,000km altitude change, 30° inclination change from LEO, or an 80° inclination change from GEO.[2] During operations, the tank is heated to vaporize the propellant. The thruster then ionizes the vapor and accelerates it via magnetic and electrostatic fields, resulting in high specific impulse.

      --
      [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
      • (Score: 2) by c0lo on Monday October 16 2017, @01:53PM

        by c0lo (156) on Monday October 16 2017, @01:53PM (#582988) Journal

        This even letting aside you have a disinfectant at hand if you scratch yourself during an EVA - who knows what looms into that filthy LEO, with no anti-tetanus vaccines?

        (grin)

        --
        https://www.youtube.com/watch?v=aoFiw2jMy-0
    • (Score: 1) by khallow on Monday October 16 2017, @01:27PM

      by khallow (3766) Subscriber Badge on Monday October 16 2017, @01:27PM (#582978) Journal

      Back to this ion engine, isn't the xenon used for propellent about 10 times the price of petroleum?

      That's not very expensive. Keep in mind that that's it's at least another order of magnitude on top of that (even on the cheapest rocket) in cost to put that xenon in space where electric propulsion would operate.

  • (Score: 2) by esperto123 on Monday October 16 2017, @10:18AM (5 children)

    by esperto123 (4303) on Monday October 16 2017, @10:18AM (#582945)

    Isn't 102kW (or more than 100hp) for 5.4N just horribly inefficient?

    i understand that the advantages of this type of thruster is that is consumes almost no mass compared to chemical rockets and can operate for very long periods, which could result in high speeds, but considering how small the force is, and the amount of mass needed to produce hundreds of kilowatts using solar panels to get such small nudges, no wonder it is not in use.

    Do anyone knows what is the theoretical efficiency limit of a hall thruster? are they any close to it or there are much more room for improvement?

    • (Score: 0) by Anonymous Coward on Monday October 16 2017, @10:43AM

      by Anonymous Coward on Monday October 16 2017, @10:43AM (#582951)

      But yes, this is a transit engine, not an entry/exit engine.

    • (Score: 3, Informative) by takyon on Monday October 16 2017, @11:09AM (2 children)

      by takyon (881) <takyonNO@SPAMsoylentnews.org> on Monday October 16 2017, @11:09AM (#582957) Journal

      Time for the crash course on ion engines [wikipedia.org]:

      An ion thruster or ion drive is a form of electric propulsion used for spacecraft propulsion. It creates thrust by accelerating ions with electricity. The term refers strictly to gridded electrostatic ion thrusters, but may more loosely be applied to all electric propulsion systems that accelerate plasma, since plasma consists of ions.

      Ion thrusters are categorized by how they accelerate the ions, using either electrostatic or electromagnetic force. Electrostatic thrusters use the Coulomb force and accelerate the ions in the direction of the electric field. Electromagnetic thrusters use the Lorentz force. In either case, when an ion passes through an electrostatic grid engine, the potential difference of the electric field converts to the ion's kinetic energy.

      Ion thrusters have an input power need of 1–7 kW, exhaust velocity 20–50 km/s, thrust 25–250 millinewtons and efficiency 65–80%.

      [...] Ion thrusters' low thrust requires continuous thrust for a long time to achieve the necessary change in velocity (delta-v) for a particular mission. Ion thrusters are designed to provide continuous operation for intervals of weeks to years.

      [...] Ion thrusters have many in-space propulsion applications. The best applications make use of the long mission interval when significant thrust is not needed. Examples of this include orbit transfers, attitude adjustments, drag compensation for low Earth orbits, fine adjustments for scientific missions and cargo transport between propellant depots, e.g., for chemical fuels. Ion thrusters can also be used for interplanetary and deep-space missions where acceleration rates are not crucial. Continuous thrust over a long interval can reach high velocities while consuming far less fuel than traditional chemical rockets.

      Simply put, they enable spacecraft to travel much faster over time than chemical rockets would allow, and you can do finer adjustments to trajectory by activating the engine over a long period of time.

      https://www.space.com/28732-nasa-dawn-spacecraft-ion-propulsion.html [space.com]

      Ion propulsion has also allowed Dawn's handlers to craft a slow, gentle approach to that should result in a low-stress orbital arrival. There will be no critical, make-or-break orbital-insertion burns, such as the ones that typically deliver orbiters to Mars and other deep-space destinations.

      "We just slip right in, and there's no moment of truth or anything like that," Dawn principal investigator Christopher Russell of UCLA told Space.com. "So it's boring but safe."

      Dawn will continue to demonstrate the advantages of ion engines after it reaches Ceres, Russell added.

      "When we get into orbit, we can optimize our trajectory," he said. "If we want to be in a particular local time sector, or we want to be at a particular altitude or particular sun angle — things of that nature — we can go there and, with the ion propulsion engine, tailor that orbit very easily."

      --
      [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
      • (Score: 2) by bob_super on Monday October 16 2017, @06:55PM (1 child)

        by bob_super (1357) on Monday October 16 2017, @06:55PM (#583098)

        That's a good thing for a robotic probe.
        TFS hints about human transport, where every day spent traveling means a lot more mass to push in the first place.
        If they make this light enough to be worth its 5.4N contribution, it's a good extra help. But at that level, it cannot be the primary for human missions, even if we only ship toddlers.

        • (Score: 2) by takyon on Monday October 16 2017, @07:30PM

          by takyon (881) <takyonNO@SPAMsoylentnews.org> on Monday October 16 2017, @07:30PM (#583125) Journal

          They say "500 kW-1 MW" or more would be used for a manned mission. That's more than 5.4 Newtons of thrust.

          The Dawn spacecraft [wikipedia.org] could accelerate from 0 to 96km/h in 4 days using 0.09 N of thrust.

          That's +4320 km/h in 6 months (typical length of a journey to Mars).

          Manned spacecraft are more massive, but if the thrust is over 500x higher (at the 1 MW level), then the acceleration may be significant over the duration of the mission.

          ((1 MW / 102 kW) * 5.4 N) / 0.09 N = 588x more thrust than Dawn. If we go as high as 2 MW, you can double that. For a spacecraft 100x more massive than Dawn, that would be 0 to 96 km/h in 8 hours, 9 minutes, and 36 seconds instead of 4 days. That should increase velocity by 50,823 km/h in 6 months. That is added to whatever relative velocity the spacecraft already achieved using chemical rockets to escape Earth.

          r8 my math

          --
          [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 0) by Anonymous Coward on Monday October 16 2017, @11:15AM

      by Anonymous Coward on Monday October 16 2017, @11:15AM (#582961)

      Do anyone knows what is the theoretical efficiency limit of a hall thruster?

      Current efforts peak around 60% efficiency, no idea what the theoretical limit of the X3 is. There are a few papers here [umich.edu] that may cover this, should anyone have the time and inclination to read them.

(1)