Author Topic: Wind Rider: A High Performance Magsail (Jupiter in a month)  (Read 16407 times)

Offline aceshigh

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https://www.centauri-dreams.org/2021/11/19/wind-rider-a-high-performance-magsail/

"The Plasma Magnet was proposed by Slough [5] and involved an arrangement of coils to co-opt the solar wind ions to induce a very large magnetosphere that is propelled by the solar wind. Unlike earlier proposals for magnetic sails that required a large electric coil kilometers in diameter to create the magnetic field, the induction of the solar wind ions to create the field meant that the structure was both low mass and that the size of the resulting magnetic field increased as the surrounding particle density declined. This allowed for a constant acceleration as the PM was propelled away from the sun, very different from solar sails and even magsails with fixed collecting areas.

The PM concept has been developed further with a much sexier name: the Wind Rider, and missions to use this updated magsail vehicle are being defined."


"The main upgrade from the earlier PM to the Wind Rider is the substitution of superconducting coils. This allows the craft to maintain the magnetic field without requiring constant power to maintain the electric current, reducing the required power source. Because the superconducting coils would quickly heat up in the inner system and lose their superconductivity, a gold foil reflective sun shield is deployed to shield the coils from the sun’s radiation. This is shown in the image above with the shield facing the sun to keep the coils in shadow. The shield is also expected to do double duty as a radio antenna, reducing the net parasitic mass on the vehicle."

"The performance of the Wind Rider is very impressive. Calculations show that it will accelerate very rapidly and reach the velocity of the solar wind, about 400 km/s. This has implications for the flight trajectory of the vehicle and the mission time."


"How does the performance of the Wind Rider compare to other comparable missions?

The JUNO space probe to Jupiter had a maximum velocity of about 73 km/s as Jupiter’s gravity accelerated the craft towards the planet. The required gravity assists and long flight path, about 63 AU or over 9 billion km, mean that its average velocity was about 60 km/s. This is not the fairest comparison as the JUNO probe had to attain orbital insertion at Jupiter.

A fairer comparison is the fastest probe we have flown – the New Horizons mission to Pluto — which reached 45 km/s as it left Earth but slowed to 14 km/s as it flew by Pluto. New Horizons took 1 year to reach Jupiter to get a gravity assist for its 9 year mission to Pluto, and therefore a maximum average velocity of 19 km/s between Earth and Jupiter.

Wind Rider can reach Jupiter in less than a month. Figure 2 shows the almost straight-line trajectory to Jupiter. Launched just before opposition, Wind Rider reaches Jupiter in just over 3 weeks. Because opposition happens annually, a new mission could be launched every year.

As the Wind Rider quickly reaches its terminal velocity at the same velocity as the solar wind, it can reach the outer planets with comparably short times with the same trajectory and annual launch windows.

The Wind Rider can fly by Saturn in just 6 weeks, and Neptune in 18 weeks. Compare that to the Voyager 2 probe launched in 1977 that took 4 years and 12 years to fly by the same planets respectively. Pluto could be reached by Wind Rider in just 6 months."

Offline endlesslimitation

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Neat! I like the plasma magnet idea in general. I'm curious how big of a magnetosphere bubble this can generate in practice (in a real space environment, with real materials that have limits on critical current and critical temperature). If the bubble is indeed orders of magnitude larger than the superconducting coil itself, and also efficiently transfers momentum from the solar wind to the ship, as the proponents claim, then it could be a real game changer.

Offline su27k

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Offline sghill

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This concept has been around at least since the 1980s. I remember an Omni magazine blurb way back then.

Another interesting application of this drive is as a fixed ring on towers around a Mars colony to protect it from radiation by deflecting incoming charged particles and cosmic rays.
« Last Edit: 12/06/2021 11:52 am by sghill »
Bring the thunder!

Offline mikelepage

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This seem a natural technology to put in combination with an asteroid based habitat as suggested by Paul451 here:

IMO, no large rotating settlement, such as an O'Neill, will ever be flown "naked". It'll either be built inside an asteroid, or surrounded by a non-rotating shell serving the same role.

I know this is a bit of a tangent, but I have to say, I'm less excited by the prospect of using this tech to send very small probes at very high speeds, than of taking large objects (like say asteroids in the 600-1000m size class), and tweaking their orbits into more useful ones.

A few background assumptions here:
* The asteroid starts by having a toroidal tunnel bored through it in such a way that "train car modules" running along the tunnel can start to cancel out the spin of the asteroid, and provide spin gravity at the same time.
* Add enough "carriages" to the train, and enough tunnels in the asteroid, and your habitats effectively double as reaction wheels, eventually allowing you to neutralise its spin completely and point the asteroid as desired.
* Placing the wind-rider array on one side of the asteroid will allow you to adjust that asteroid's orbit into one that regularly rendezvouses with other asteroids.
*The large mass of the asteroid would have the side benefit of allowing you to hold the wind-rider array at an angle to the solar wind, so as to make finer adjustments to the trajectory.

I think having many maneuverable asteroids in orbits that regularly rendezvous with each other makes the prospect of regular trade across an asteroid belt-sized civilisation a bit more realistic.  At some point, the asteroids cease to even resemble asteroids, as the construction consumes the remaining raw material. Once they build large enough wind-rider arrays, the asteroid-derived habitat becomes a generation ship that could comfortably make the 3000-odd year journey that 450km/s would give you to the closest star.

Offline lamontagne

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Neat! I like the plasma magnet idea in general. I'm curious how big of a magnetosphere bubble this can generate in practice (in a real space environment, with real materials that have limits on critical current and critical temperature). If the bubble is indeed orders of magnitude larger than the superconducting coil itself, and also efficiently transfers momentum from the solar wind to the ship, as the proponents claim, then it could be a real game changer.
Extremely large.  Many km in diameter.  that is why the high speeds can be reached.

Offline lamontagne

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Previous thread on this: https://forum.nasaspaceflight.com/index.php?topic=50611.0
This is basically the same idea, but the proposal is for a small test that does not require nuclear power, so it should be much easier to do a proof of concept vehicle.  the current incarnation of the minimal vehicle is a 'fat' 16U cubesat, called "Jove".
There is also a latter nuclear powered version for more extensive missions, called "Pip".
« Last Edit: 12/14/2021 04:32 pm by lamontagne »

Offline lamontagne

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This is also an interesting possibility for future higher power missions :

"This “Wind Rider” propulsion system can potentially also decelerate against the Jovian plasmapause dawn eddy, to enable Jupiter orbital insertion in future missions. "

https://baas.aas.org/pub/2021n7i314p05/release/1

Three months to Jupiter insertion, now wouldn't that be nice :-)

Offline lamontagne

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From the poster image.  The rings carry the superconductors that create the magnetic sail.  The square area is the shadow shield to keep the rings superconducting.  The cross in the shadow is deployed solar panels used to tension the shadow shield.

The central little box is a 16U cubesat frame. 
The ship wouldn't deploy in LEO.  The image is artistic license  ;)
« Last Edit: 12/14/2021 04:33 pm by lamontagne »

Offline aceshigh

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Has anyone seen some extrapolation of how big this system would need to be, in order to maintain these mission times while carrying several tons (manned missions)?

Would it be feasible?

Offline lamontagne

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #10 on: 12/14/2021 06:47 pm »
Has anyone seen some extrapolation of how big this system would need to be, in order to maintain these mission times while carrying several tons (manned missions)?

Would it be feasible?
It appears to be very scalable.  However, a demonstrator is required to show that the physics actually work, that the plasma sail actually builds up as planed and that the plasma/sail interactions are as expected.

In a way this is a little like the "Starship/BFR and science instruments" thread.  It's hard to get support as long as there are other, safer ways to get things done.

Offline edzieba

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #11 on: 12/15/2021 07:30 am »
Though it is substantially easier to design a 16U demonstrator to fly as a secondary payload on a 'mission to anywhere' (it's a demonstrator, as long as the orbit is suitable for the thermal environment it needs you don't really care where it is or can go) on any launch vehicle available, than it is to wed a large project solely to a single future launch system.

Offline lamontagne

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #12 on: 12/15/2021 01:16 pm »
Though it is substantially easier to design a 16U demonstrator to fly as a secondary payload on a 'mission to anywhere' (it's a demonstrator, as long as the orbit is suitable for the thermal environment it needs you don't really care where it is or can go) on any launch vehicle available, than it is to wed a large project solely to a single future launch system.

I believe the plan was to ride on this, or on the next one:
Spaceflight Inc announces rideshare mission to the moon and geostationary orbit
https://www.nasaspaceflight.com/2021/09/spaceflight-inc-rideshare-moon-geostationary/

Loiter in orbit until Jupiter is in the right spot, then deploy and take off.

Offline FattyLumpkin

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #13 on: 01/14/2022 04:42 pm »
Please see my comments above in "Rotating Magnetic Field as a Propeller in the Solar Wind" ,  K Hambsch
Hello Michel!!!

Online Bob Shaw

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #14 on: 01/14/2022 05:03 pm »
Has there been any consideration of using this technology as a mechanism for slowing down a vehicle, ie for inner-planet fast transfers (superior to inferior) or interstellar deceleration?

Offline lamontagne

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #15 on: 01/14/2022 05:08 pm »
Please see my comments above in "Rotating Magnetic Field as a Propeller in the Solar Wind" ,  K Hambsch
Hello Michel!!!
Hello, is that Kevin under that peculiar name?
Jeffrey Greason is soon going to publish a new paper on the energy extraction aspects of the Magsail.

The question now is: How do we drum up enough money to make a test article?

Offline lamontagne

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #16 on: 01/14/2022 05:13 pm »
Has there been any consideration of using this technology as a mechanism for slowing down a vehicle, ie for inner-planet fast transfers (superior to inferior) or interstellar deceleration?
Yes, there are ideas; managing to develop possible applications in this area may well be key to getting the proof of concept funded.  There is more $ in near space than far space :-).  The Jeffrey Greason paper should address this, one hopes.

Offline FattyLumpkin

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #17 on: 01/15/2022 09:15 am »
The Plasma Magnetic sail collects electrons, not Ions.
The speed of rotation (of the mag. field) is ~ 3 hertz at 1AU. This rotational speed is just below the cyclotron resonant frequency of the electrons and is too fast for the ions/protons to "catch up" to it, per their significant mass. This rotational speed drops as the sail moves farther away from the sun to compensate for the drop in dynamic pressure.
Additionally, although the coils are round in shape they do not form an electron populated globe-like shape...Goes without saying that because the coils are at different distances from the center axis there will be a different distance-rotational speed MF relationship.
Dr. Slough suggests the sail would take on a disk shape. Good thing for that as it would make the sail steerable. Am going to have to snip an image from the paper that best illustrates why the sail is disk like. Will modify/ attach it on the morrow.  FL
« Last Edit: 01/15/2022 09:17 am by FattyLumpkin »

Offline sumlif

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #18 on: 06/01/2022 07:21 pm »
The Plasma Magnetic sail collects electrons, not Ions.
The speed of rotation (of the mag. field) is ~ 3 hertz at 1AU. This rotational speed is just below the cyclotron resonant frequency of the electrons and is too fast for the ions/protons to "catch up" to it, per their significant mass. This rotational speed drops as the sail moves farther away from the sun to compensate for the drop in dynamic pressure.
Additionally, although the coils are round in shape they do not form an electron populated globe-like shape...Goes without saying that because the coils are at different distances from the center axis there will be a different distance-rotational speed MF relationship.
Dr. Slough suggests the sail would take on a disk shape. Good thing for that as it would make the sail steerable. Am going to have to snip an image from the paper that best illustrates why the sail is disk like. Will modify/ attach it on the morrow.  FL

When I read this paper (not the Centauri dreams post),https://www.researchgate.net/publication/358839818_Jupiter_Observing_Velocity_Experiment_JOVE_Introduction_to_Wind_Rider_Solar_Electric_Propulsion_Demonstrator_and_Science_Objectives I believed that the value in Table 1 of 4Hz for the Power Supply was inconsistent with Slough06 with my reasoning summarized below.

The cyclotron frequency is f=ZeB/mi/2/Pi https://en.wikipedia.org/wiki/Ion_cyclotron_resonance.
At magnetopause Bwr=w*Sqrt(rho*Mu0)~5x10-8T with  rho the plasma density and w the plasma wind speed, then as stated in Eq. (7) of the WindRider paper  f*5~4Hz. However, in [Slough06] the discussion after Eq. (1a) applies to the cyclotron frequency near the antenna coils at radius Rcoil, NOT at magnetopause Rwr meaning that in Eq. (7) of the WindRider paper Bwr should be replaced by Bcoil. As stated in Eq. (5) of the WindRider paper the 1/r magnetic field falloff assumed in [Slough06] means that Bcoil=Bwr*Rwr/Rcoil (same as Eq.8 of [Slough06]).  For Rcoil=4.5 m and Rwr=10 km then Bcoil~10-1T and f*5=8kHz. 

Note from Eq.5 of [Slough06] that current density falls off as 1/r2, which means that as magnetic field falls off as 1/r that the RMF will have the most impact on the electrons nearest the coils.

As further evidence observe that in the plasma wind chamber experiments of [Slough06, p.27] Rcoil=9 cm and [Slough06, p.29] f=108 kHz. The text preceding Eq. (16) of [Slough06] states that the product of omega (2*Pi*f) and the antenna radius RA (Rcoil) should be held constant. Increasing Rcoil would reduce f by 50 fold, or f~2 KHz.

This may be a problem for usage of superconducting coils, which are great at DC but may exhibit significant resistivity with AC, especially at higher frequencies.

As far as an illustration of the "disk-like" shape of the rotating electrons, the RMD_cartoon.avi at https://earthweb.ess.washington.edu/space/PlasmaMag/ is a good animated illustration of this phenomenon.
« Last Edit: 09/11/2023 08:38 pm by sumlif »

Offline sumlif

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Re: Wind Rider: A High Performance Magsail (Jupiter in a month)
« Reply #19 on: 06/01/2022 07:43 pm »
https://www.centauri-dreams.org/2021/11/19/wind-rider-a-high-performance-magsail/

"The Plasma Magnet was proposed by Slough [5]

Reference [5] in the citation has the wrong date (1970) which should be 2004 and is also Phase I to the study. Phase II of the study (2006) can be accessed at the following URL. It contains updates to theoretical results as well as the majority of experimental results:

http://www.niac.usra.edu/files/studies/final_report/917Slough.pdf

The 2005 presentation http://www.niac.usra.edu/files/library/meetings/annual/oct05/917Slough.pdf is also good and clarifies citations from references and has good graphics and concise explanations.

 

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