Author Topic: Magnetoshell Aerobraking & Aerodynamics  (Read 43295 times)

Offline sanman

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Magnetoshell Aerobraking & Aerodynamics
« on: 09/16/2012 12:01 AM »
Can magnetoshells be used for more effective aerobraking and aerodynamics, whether on Earth or other planets?

http://www.nasa.gov/offices/oct/early_stage_innovation/niac/2012_phase_I_fellows_kirtley.html


Offline aero

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #1 on: 09/16/2012 12:41 AM »
Well, according to the link you provided, yes.

I'm wondering if they can be used to benefit reusablity of rocket first and second stages. I would think yes for the second stage, maybe for the first stage due to the high atmospheric density and required ionization energy.

Of course that is contingent on their working at all.
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Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #2 on: 09/16/2012 02:22 AM »
Well, I'm assuming it provides relatively more benefit in thinner atmosphere, since there's probably no boundary layer issues with this.


Also, they mention manned landings, so I wonder if the magnetic field would be harmful to biological (human) payloads. However, they do say it's low-powered, so maybe then it's not so harmful.

I wonder if this tech would also be good for steering scramjet vehicles as well.

Offline kch

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #3 on: 09/16/2012 02:42 AM »
There is much to wonder about ... it should be interesting to revisit this thread over the years ahead as the answers become clear.  At the moment, questions are about all we have, particularly about the timeframe of this project.

Offline go4mars

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #4 on: 09/16/2012 04:08 AM »
Neato.  I wonder what kind of funding and timeline this will get.
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Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #5 on: 09/16/2012 07:19 PM »
Not wanting to deviate too much into the military sphere, but I'm curious - could this type of tech be useful for MIRV?

I was just thinking that something with potential military utility could attract much greater research funding, thus accelerating its development and progress.
« Last Edit: 09/16/2012 07:28 PM by sanman »

Offline Cedalion

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #6 on: 09/20/2012 04:13 AM »

Offline Jim

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #7 on: 09/20/2012 11:23 AM »
Not wanting to deviate too much into the military sphere, but I'm curious - could this type of tech be useful for MIRV?


How so?  They don't need braking.

Offline spaceStalker

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #8 on: 09/20/2012 01:02 PM »
Not wanting to deviate too much into the military sphere, but I'm curious - could this type of tech be useful for MIRV?


How so?  They don't need braking.

Someone has to pay for the development :)

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #9 on: 09/20/2012 01:10 PM »
Not wanting to deviate too much into the military sphere, but I'm curious - could this type of tech be useful for MIRV?


How so?  They don't need braking.

No, but anything that can be used for braking can be used for steering as well - just manipulate the field. Certainly MIRVs could benefit from being steered to target, or even steered for evasive purposes on the way down.
« Last Edit: 09/20/2012 01:11 PM by sanman »

Online Asteroza

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #10 on: 09/21/2012 12:47 AM »
Powering the magnets for this may be non-trivial.

But there may be a solution, for aerobraking around bodies with magnetospheres, such as earth.

Assuming the magnet is superconducting, if you had a source of power/current to quick charge the magnet, you could leave it unmagnetized most of the time.

So what would be the power source? How about a disposable braking electrodynamic tether? Since you are low in the magnetosphere and traveling a high velocity, you can generate a fair amount of power from a braking tether. As an additional factor, while the tether itself won't provide enough reduction in deltaV to make reentry painless, but it may provide enough to avoid a large retro burn for reentry. May need a drag kite plate at the end of the tether to use atmospheric drag to steer the tether upright, otherwise it would just stream behind the space craft.

How it would interact with the growing field from the reentry magnet is an issue. The tether does have the convenient aspect of burning loose when reentry gets warmer (though it needs to be able to deorbit by its own drag when cut loose).

Online KelvinZero

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #11 on: 09/21/2012 01:35 AM »
Hopefully it creates its own power as it applies drag against the ionised atmosphere like a form of MHD generator?

Im unclear about the expected weight of this contraption though.. they did seem to dismiss it a bit glibly by describing it as "a massless field and a gram of plasma".
« Last Edit: 09/21/2012 01:39 AM by KelvinZero »

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #12 on: 09/21/2012 02:18 AM »
This reminds me of some interesting work I saw a while ago on using magneto-hydrodynamic forces for aerobraking and thermal protection...

Here it is - probably discussed previously on this forum somewhere:
http://selenianboondocks.com/2010/02/mhd-aerobraking-and-thermal-protection-part-i-introduction/
http://selenianboondocks.com/2010/02/mhd-aerobraking-and-thermal-protection-part-ii-atmospheric-reentry-for-rlvs/
http://selenianboondocks.com/2010/02/mhd-aerobraking-and-thermal-protection-part-iii-aerobraking-and-aerocapture/

Yeah, I enjoyed writing those articles. I've pinged the guy who is running that NIAC project to see if I can do another blog post about their idea and how it differs from these other approaches.

~Jon
« Last Edit: 09/21/2012 02:22 AM by jongoff »

Offline Jim

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #13 on: 09/21/2012 03:02 AM »

No, but anything that can be used for braking can be used for steering as well - just manipulate the field. Certainly MIRVs could benefit from being steered to target, or even steered for evasive purposes on the way down.

They already are, using systems that are simpler and less complicated.

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #14 on: 09/21/2012 03:18 AM »

No, but anything that can be used for braking can be used for steering as well - just manipulate the field. Certainly MIRVs could benefit from being steered to target, or even steered for evasive purposes on the way down.

They already are, using systems that are simpler and less complicated.

Okay, fair enough, Jim - but what about stuff like hypersonic vehicles/missiles? A recent hypersonic test failed because the control surfaces weren't effective. With magnetism, you could probably exert much better control authority, without worrying about mechanical failure due to the high stresses of hypersonic flight.

Offline Jim

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #15 on: 09/21/2012 03:39 AM »

Okay, fair enough, Jim - but what about stuff like hypersonic vehicles/missiles? A recent hypersonic test failed because the control surfaces weren't effective. With magnetism, you could probably exert much better control authority, without worrying about mechanical failure due to the high stresses of hypersonic flight.

My point is still applicable.  Still have the greater complexity in generating the power and then manipulating the magnetic field.

And no, you wouldn't have more control authority and the magnetic field would have more drag.

Also, not every discovery has spaceflight implications. That is all you seem to post.  "oh, here is something new, can it be used for space'?

"This one a long time have I watched. All his life has he looked away... to the future, to the horizon. Never his mind on where he was. "
« Last Edit: 09/21/2012 03:44 AM by Jim »

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #16 on: 09/21/2012 04:49 AM »
Well, Jim, the link in my original post was from NASA - apparently they feel that Magnetoshells may have applications for spaceflight purposes.

And yes, I feel that we should always look at new developments in science and technology, and assess their implications for things that are useful to us.

Brakes/drag when applied selectively can be used to steer with, and that would likewise apply to magnetic braking/drag.

The problem with conventional mechanical braking in the hypersonic regime is the insufficient level of contact - especially in less dense atmosphere. That's why Curiosity had to land with rockets, because there wasn't enough atmosphere for the chutes to grab onto. A magnetic field could be expanded to contact much more atmosphere, to grab at it. And because it doesn't have conventional moving parts, it's less prone to failure.




Offline Jim

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #17 on: 09/21/2012 10:05 AM »

The problem with conventional mechanical braking in the hypersonic regime is the insufficient level of contact - especially in less dense atmosphere. That's why Curiosity had to land with rockets, because there wasn't enough atmosphere for the chutes to grab onto. A magnetic field could be expanded to contact much more atmosphere, to grab at it. And because it doesn't have conventional moving parts, it's less prone to failure.

Wrong on all accounts.  You have no basis to make such statements.

Offline RanulfC

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #18 on: 09/21/2012 12:18 PM »

The problem with conventional mechanical braking in the hypersonic regime is the insufficient level of contact - especially in less dense atmosphere. That's why Curiosity had to land with rockets, because there wasn't enough atmosphere for the chutes to grab onto. A magnetic field could be expanded to contact much more atmosphere, to grab at it. And because it doesn't have conventional moving parts, it's less prone to failure.

Wrong on all accounts.  You have no basis to make such statements.
I'll use Jims post to point out some "information" that seems to have been "lost" in the discussion;

Magnetic fields only cause "drag" within magnetic fields not within a medium itself. Toss a magnet and you won't see it "slowing" down until the ground interupts its free-fall trajectory :)

THIS system uses very high hypersonic speeds (talking over Mach-12 here) to generate a PLASMA which is then manipulated by a magnetic field into acting like a larger surface area for atmospheric, (not magnetic) interfacing. While it can be used to "steer" by manipulating the size, shape, and density of the plasma the effect is going to be less effective as pressure increases due to the nature of the plasma itself.

The power requirements would seem to be modest as it says it would require NO superconductors.

The biggest "issue" with Mars EDL for large payloads is the SIZE of parachutes needed for soft landing, this concept doesn't really "help" with that other than allowing a higher deceleration to be achieved in the very thin upper atmosphere. You would still need large parachutes (or rockets) to continue to decellerate once the speed no longer generated a sufficent plasma for the magnetic field to manipulate.

You would need an EXTREMELY powerful magnetic field generator to get ANY "control" without the plasma field and then you would NOT be interacting with the atmosphere but the planetary magnetic field. Magnetic "control" doesn't work simply because of the power and field strength requirments to even BEGIN interacting enough to be noticed :)

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Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #19 on: 09/21/2012 04:26 PM »
The area where (depending on details of how this works) I'm most interested in this and related MHD aerobraking concepts is in enabling capture and reuse of in-space elements. Ie, think real spaceships, that get reused a bunch of times, that don't have to look like a big reentry capsule.

Imagine for instance if you could use this to take Centaur-derived tanker coming back from L2, and brake it into LEO using a miniscule amount of propellant.

Or imagine having a spacecraft like Nautilus-X, or a combination of Bigelow Modules combined with a backbone and some propulsion, that used something like this to enable it to quickly and safely capture into LEO after returning from the Moon or Mars. Or capturing into Mars orbit after a trip from earth.  Being able to non-propulsively knock off most of the energy needed to go from a hyperbolic orbit to a low orbit around Earth, Mars, Venus, or anywhere with an atmosphere, without needing a huge heat shield I think might be more game changing than most realize.

That said, I'd like to get more details on how this concept works, because I'm not sure it can actually do what I'm suggesting above.

~Jon

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #20 on: 09/22/2012 08:23 AM »
So when it comes to magnetoshell aerobraking and conventional aerobraking, each will have its preferred atmospheric regime where it performs best. Nobody's claiming that magnetoshells mean you don't need conventional parachutes or aerobody surfaces, just that the magnetoshell approach can further reduce the load on the conventional aerodynamic systems. This provides an extra performance margin, while reducing the potential for failure.


Offline 93143

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #21 on: 09/22/2012 09:14 PM »
It is my understanding that the magnetoshell idea is more for aerocapture, which is currently a very dubious endeavour due to the unpredictability of upper atmosphere conditions.  The ability to directly modulate drag would be very useful here, and it might also allow greater flexibility in vehicle design.

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #22 on: 09/23/2012 02:50 AM »
But also remember that there is a higher component of ionic species in the upper atmosphere/ionosphere. So that will work even more in the magnetoshell's favor, to help its performance.

Offline aero

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #23 on: 09/23/2012 04:03 AM »
I haven't read any comments regarding the RMF. Quoting from the original link (first post) in this thread:

Quote
This plasma is formed, sustained, and expanded with an electrodeless Rotating Magnetic Field (RMF), which has been shown in previous experiments to generate the required, fully ionized, high temperature magnetized plasma.

Is that not significant?

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Offline Robotbeat

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #24 on: 09/24/2012 08:32 PM »
It is my understanding that the magnetoshell idea is more for aerocapture, which is currently a very dubious endeavour due to the unpredictability of upper atmosphere conditions.  The ability to directly modulate drag would be very useful here, and it might also allow greater flexibility in vehicle design.
Aerocapture around /Mars/ (and other non-Earth worlds) is what is dubious because of the lack of extensive knowledge about the upper atmosphere there. It's more predictable for aerocapture at Earth.
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Offline SpaceWeaselUMICH

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #26 on: 07/23/2013 09:12 AM »
It is my understanding that the magnetoshell idea is more for aerocapture, which is currently a very dubious endeavour due to the unpredictability of upper atmosphere conditions.  The ability to directly modulate drag would be very useful here, and it might also allow greater flexibility in vehicle design.
Aerocapture around /Mars/ (and other non-Earth worlds) is what is dubious because of the lack of extensive knowledge about the upper atmosphere there. It's more predictable for aerocapture at Earth.

By the time this is ready, I believe the MAVEN spacecraft will have returned scientific data on the upper atmosphere. (Assuming it avoids fiery destruction.)

Offline cordwainer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #27 on: 07/24/2013 05:06 PM »
Had a wild idea related to another thread. Would it be possible to use a designer graphene or nano-tube composite to provide thermodynamic cooling to a turbine blade. Someone though it would be a good idea to stick a turbine behind a rocket's exhaust not just the cryogenic propellant stream, don't know what use this would have except maybe in a gas generator or thermopower wave device. But they did bring up the point that rocket turbines don't have blade cooling systems. Since graphene and nanotube wires exhibit semiconductive properties, could one lace a mesh of such wires through a material to manage a electromagnetic or electrostatic field that could be used in various ways? Like for instance a lightweight Faraday cage, controlling the shape and density of a magnetoshell or magnetohydrodynamic cooling for a high temperature rocket turbine. Traditional bladed turbines probably wouldn't the best design for such an application though, perhaps a disk or screw turbine design would offer the appropriate surface area to achieve an effective gain in heat management. 

Offline mfck

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #28 on: 05/05/2014 01:18 PM »
Congrats to Jon on SBIR Selection!

Offline xanmarus

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #29 on: 05/05/2014 01:42 PM »

Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #30 on: 05/05/2014 02:53 PM »
Congrats to Jon and his team and to Dave and the other guys over at MSNW!
This is a really cool project!
« Last Edit: 05/05/2014 02:54 PM by Elmar Moelzer »

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #31 on: 05/06/2014 10:50 AM »
Thanks guys! I've been proposaling the last few days, so hadn't had a time to mention anything publicly about this, but Doug did a good writeup. This is pretty exciting for us!

~Jon

Offline JasonAW3

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #32 on: 05/07/2014 04:57 PM »
Tapping into the energy generated by the plasma during reentry could, in theory, help power such a system.
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Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #33 on: 05/07/2014 05:02 PM »
Tapping into the energy generated by the plasma during reentry could, in theory, help power such a system.
Yes, it does. It has essentially a dynamo effect. So the thing is self charging. There was a joint European Russian project at some point that was supposed to test that, but I don't think it ever happened.

Offline cordwainer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #34 on: 05/09/2014 07:28 PM »
Question could charge excitation be used to propel objects via a high pressure gas gun? A sort of hybrid compressed air gun/coil gun. Such a system could be used to test the effectiveness of magnetoshell technology as well as be used to develop future mass drivers for space propulsion and military weaponry.

Offline MP99

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #35 on: 05/09/2014 09:24 PM »
Congrats, Jon!

Offline JasonAW3

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #36 on: 05/23/2014 07:22 PM »
http://nextbigfuture.com/2013/06/magnetoshell-concept-proven-for-braking.html#more

If I understand the article correctly, this would act something like a Plasma Parachute in the upper atmosphere.

But if the Payload is actually in front of the Magnetized Plasma effect, wouldn't it too need some form of TPS?  I figure an Inflatable Hypersonic decellerator would work quite well for that.
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Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #37 on: 05/24/2014 02:53 AM »
http://nextbigfuture.com/2013/06/magnetoshell-concept-proven-for-braking.html#more

If I understand the article correctly, this would act something like a Plasma Parachute in the upper atmosphere.

Yeah, that's the analogy we use a lot. It works reasonably well.

Quote
But if the Payload is actually in front of the Magnetized Plasma effect, wouldn't it too need some form of TPS?

It depends, but not exactly. While it's true that having the spacecraft inside the magnetoshell provides an extra level of protection versus atmospheric heating, just increasing the effective drag area means you can get the same amount of braking higher in the atmosphere, where the lower density means much less heat flux.

Instead of a ballistic coefficient of 250-500kg/m^2 that you see for capsules or the shuttle, or 25-50kg/m^2 that you get for a HIAD system, you can potentially get ballistic coefficients less than 1-5kg/m^2 with a properly designed Magnetoshell with the right bells and whistles...Potentially much less than 1kg/m^2...

Take their Mars aerocapture design. Compared to a 5m radius heatshield that you could theoretically get on an SLS-type vehicle, you could get a 20m radius magnetoshell using their design, and possibly as much as 40-50m radius magnetoshell using some reasonable tricks we've thought of since they did their paper. You're talking about an areal density somewhere between 16-100x lower than you could get with a traditional heat shield (and probably still 4-25x more than you could get with a HIAD. That means that for the same desired drag, you can do a pass where the density is 16-100x lower than you could with the traditional heatshield or 4-25x lower density than you could with a HIAD. Heat flux goes linearly with the density, so depending on the details, and the knobs twisted, even if your MAC coil is trailing on a tether, you still might not actually need TPS.

Oh, and that 20-50m radius magnetoshell can be made with a payload that fits into a 5m EELV fairing...

~Jon
« Last Edit: 05/24/2014 03:12 AM by jongoff »

Offline Burninate

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #38 on: 05/24/2014 06:44 AM »
That's fantastic.  This sounds like a remarkably enabling technology.  At the outset, it means you can ferry fragile orbital habitation modules and/or fuel depots between Mars, Earth, Venus, and Titan while only incurring half of the Wrath Of The Rocket Equation, and enables both rapid grav-assist trajectories, and low-thrust SEP missions which wouldn't otherwise have the thrust to precisely hit aerocapture windows in time.  This helps the mass balance a hell of a lot, especially for missions without ISRU.  The potential for lower heat-shield requirements, especially on very large missions, is enormous.

Congratulations.
« Last Edit: 05/24/2014 06:47 AM by Burninate »

Offline MP99

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #39 on: 05/24/2014 11:53 AM »
http://nextbigfuture.com/2013/06/magnetoshell-concept-proven-for-braking.html#more

If I understand the article correctly, this would act something like a Plasma Parachute in the upper atmosphere.

Yeah, that's the analogy we use a lot. It works reasonably well.

Quote
But if the Payload is actually in front of the Magnetized Plasma effect, wouldn't it too need some form of TPS?

It depends, but not exactly. While it's true that having the spacecraft inside the magnetoshell provides an extra level of protection versus atmospheric heating, just increasing the effective drag area means you can get the same amount of braking higher in the atmosphere, where the lower density means much less heat flux.

Instead of a ballistic coefficient of 250-500kg/m^2 that you see for capsules or the shuttle, or 25-50kg/m^2 that you get for a HIAD system, you can potentially get ballistic coefficients less than 1-5kg/m^2 with a properly designed Magnetoshell with the right bells and whistles...Potentially much less than 1kg/m^2...

Take their Mars aerocapture design. Compared to a 5m radius heatshield that you could theoretically get on an SLS-type vehicle, you could get a 20m radius magnetoshell using their design, and possibly as much as 40-50m radius magnetoshell using some reasonable tricks we've thought of since they did their paper. You're talking about an areal density somewhere between 16-100x lower than you could get with a traditional heat shield (and probably still 4-25x more than you could get with a HIAD. That means that for the same desired drag, you can do a pass where the density is 16-100x lower than you could with the traditional heatshield or 4-25x lower density than you could with a HIAD. Heat flux goes linearly with the density, so depending on the details, and the knobs twisted, even if your MAC coil is trailing on a tether, you still might not actually need TPS.

Oh, and that 20-50m radius magnetoshell can be made with a payload that fits into a 5m EELV fairing...

~Jon

Jon,

Sounds like lots of advantages there.

With such low ballistic coefficients, could this be used for de-orbiting stuff from a high-ish LEO? Does sound just what F9US would need for recovery.

Also, for Mars capture... I believe this is frowned upon for crew because of risk of atmospheric variability.

This technology sounds like you could target a middling coefficient for expected conditions, then adjust it on-the-fly to ensure exactly the required capture?

Perhaps use same trick for decreasing the landing ellipse of direct entries?

I'm wondering if an element of lift is available by shaping the magnetic field?

Cheers, Martin

Offline Hanelyp

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #40 on: 05/24/2014 06:30 PM »
At least some variants of magnetic plasma shell would have a character of compressing in response to the atmosphere they pass through, presenting less drag area when passing through a higher pressure atmosphere.  Which would be very good for aerocapture through uncertain atmospheric density.

Offline JasonAW3

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #41 on: 05/26/2014 04:20 AM »
http://nextbigfuture.com/2013/06/magnetoshell-concept-proven-for-braking.html#more

If I understand the article correctly, this would act something like a Plasma Parachute in the upper atmosphere.

Yeah, that's the analogy we use a lot. It works reasonably well.

Quote
But if the Payload is actually in front of the Magnetized Plasma effect, wouldn't it too need some form of TPS?

It depends, but not exactly. While it's true that having the spacecraft inside the magnetoshell provides an extra level of protection versus atmospheric heating, just increasing the effective drag area means you can get the same amount of braking higher in the atmosphere, where the lower density means much less heat flux.

Instead of a ballistic coefficient of 250-500kg/m^2 that you see for capsules or the shuttle, or 25-50kg/m^2 that you get for a HIAD system, you can potentially get ballistic coefficients less than 1-5kg/m^2 with a properly designed Magnetoshell with the right bells and whistles...Potentially much less than 1kg/m^2...

Take their Mars aerocapture design. Compared to a 5m radius heatshield that you could theoretically get on an SLS-type vehicle, you could get a 20m radius magnetoshell using their design, and possibly as much as 40-50m radius magnetoshell using some reasonable tricks we've thought of since they did their paper. You're talking about an areal density somewhere between 16-100x lower than you could get with a traditional heat shield (and probably still 4-25x more than you could get with a HIAD. That means that for the same desired drag, you can do a pass where the density is 16-100x lower than you could with the traditional heatshield or 4-25x lower density than you could with a HIAD. Heat flux goes linearly with the density, so depending on the details, and the knobs twisted, even if your MAC coil is trailing on a tether, you still might not actually need TPS.

Oh, and that 20-50m radius magnetoshell can be made with a payload that fits into a 5m EELV fairing...

~Jon

Jon,

Sounds like lots of advantages there.

With such low ballistic coefficients, could this be used for de-orbiting stuff from a high-ish LEO? Does sound just what F9US would need for recovery.

Also, for Mars capture... I believe this is frowned upon for crew because of risk of atmospheric variability.

This technology sounds like you could target a middling coefficient for expected conditions, then adjust it on-the-fly to ensure exactly the required capture?

Perhaps use same trick for decreasing the landing ellipse of direct entries?

I'm wondering if an element of lift is available by shaping the magnetic field?

Cheers, Martin

Sounds more like an excellent system for doing aero capture.
My God!  It's full of universes!

Online TrevorMonty

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #42 on: 05/26/2014 04:49 AM »
Sounds like it can be used on more delicate spacecraft eg SEP tugs. If plasma field is big enough would protect solar panels from airstream?

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #43 on: 05/26/2014 04:14 PM »
Jon,

Sounds like lots of advantages there.

Yeah, if this stuff works as advertised (and as preliminary proof-of-concept tests MSNW has done in a ersatz arcjet tunnel indicate), I could really see this becoming a key piece of how things are moved around in space.

Quote
With such low ballistic coefficients, could this be used for de-orbiting stuff from a high-ish LEO? Does sound just what F9US would need for recovery.

MAC only works at fairly low altitudes (85km on the low end up to maybe 150-200km at the high end), which means you have to get the perigee low via some other means. But once you've done this, you can bleed off a lot of velocity on the way in. How much will depend strongly on details. :-)

Quote
Also, for Mars capture... I believe this is frowned upon for crew because of risk of atmospheric variability.

This technology sounds like you could target a middling coefficient for expected conditions, then adjust it on-the-fly to ensure exactly the required capture?

Perhaps use same trick for decreasing the landing ellipse of direct entries?

One of the things we and MSNW want to demo with the MAC demo cubesat is the ability to actively vary the magnetoshell drag area to effect real-time drag modulation. Which would enable exactly what you're suggesting. There will obviously need to be some further research to optimize the guidance targeting of such a system once we have some data on how well it performs at full scale, in space, compared to theoretical models. But yeah, this is one of the capabilities we're trying to get to.

Quote
I'm wondering if an element of lift is available by shaping the magnetic field?

That's less clear. The only way I can see to get an off-axis thrust is if you could somehow control the average velocity vectors of magnetoshell ions immediately prior to charge exchange. That might be possible, but I'm not a plasma physicist.

~Jon

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #44 on: 05/26/2014 04:15 PM »
Sounds like it can be used on more delicate spacecraft eg SEP tugs. If plasma field is big enough would protect solar panels from airstream?

Potentially yes. I think the key is that by lowering the ballistic coefficient, you can produce the same drag at a much lower dynamic pressure, even ignoring any effects of the magnetoshell on the flow of atmosphere around the spacecraft. The magnetoshell's ability to redirect particles is hopefully of secondary importance.

~Jon

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #45 on: 05/26/2014 11:13 PM »
I'm wondering if an element of lift is available by shaping the magnetic field?

That's less clear. The only way I can see to get an off-axis thrust is if you could somehow control the average velocity vectors of magnetoshell ions immediately prior to charge exchange. That might be possible, but I'm not a plasma physicist.

~Jon

Is this partially because you are using a single field, creating a uniform balloon effect, to create a drag anchor? How feasible is it to make the field "lumpy"?

Offline MP99

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #46 on: 05/27/2014 07:48 AM »
Jon,

Thanks for the clarifications.

Cheers, Martin

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #47 on: 06/24/2014 12:40 PM »
Jon

in your blog entry you mentioned 250Wh battery and 1kW power. I assume that the peak power will be mainly used for plasma generation during the magnetoshell formation. How long would that phase last? And what power requirements do you expect during the magnetoshell maintenance period?

If I understand the concept well, you would use PV to charge the battery during several orbits and then perform up to 15 minutes breaking operation.


Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #48 on: 06/24/2014 01:58 PM »
In your blog entry you mentioned 250Wh battery and 1kW power. I assume that the peak power will be mainly used for plasma generation during the magnetoshell formation.

Actually most of the power is for the electromagnet coil, the plasma generator should be a much lower fraction of the power.

Quote
How long would that phase last? And what power requirements do you expect during the magnetoshell maintenance period?

If you look at their NIAC final report that I linked to, for most aerocapture/aerobraking applications, you're only in the altitude band where MAC works for ~2-3min. Once you're out of that band, you may as well shut the thing down. If you're trying to do magnetoshell aeroentry, my very un-optimized BOTE analysis suggests you might be looking at more like 5-6min of "on time".

Quote
If I understand the concept well, you would use PV to charge the battery during several orbits and then perform up to 15 minutes breaking operation.

Actually, for the current MAC demo concept we weren't planning on charging the battery using the PV cells. That could change by the time we go to flight, but our baseline concept was to use the battery like an electron fuel tank, where we'd only get ~10 "passes" before the battery is used up. For normal MAC operations, you'd be right, but this is just a "keep it as simple as possible" tech demo. Plus we'd be starting form a low enough altitude, that one battery worth may be all we can get anyway before the thing slows down enough to reenter.

~Jon

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Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #50 on: 07/10/2014 02:15 AM »
The project featured in New Scientist:

http://www.newscientist.com/article/mg22329763.100-magnetic-bubble-may-give-space-probes-a-soft-landing.html

Yeah, a few of the details got garbled in translation, but overall it's good to get press.

~Jon

Online TrevorMonty

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #51 on: 12/16/2014 01:26 AM »
Hi Jon

When is this mission due to fly?


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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #52 on: 12/16/2014 07:50 PM »
Just a question if anyone can answer this. adding together the weight of the magnet, weight of power supply and storage,  would it be simpler and lighter to make a carbon fiber or fiberglass reinforced mylar parachute? Some sort of way to control the size wouldn't be hard. The force total on the magnetic brake was maximum 10N and a area of 100m according to IEPC-2011-304 paper. It doesn't say mass of the system though.
 I'm thinking something like 100 grams a square meter will be 1000kg for a 100m parachute to use the upper atmosphere. That arbitrary number for mass is heavy, but it illustrates the point in that the mass of the parachute for high altitude braking might be lighter than a magnetoshell.

I am of course also thinking the parachute will be durable enough to handle hypersonic atmosphere due to the low pressure and density of the atmosphere.

please feel free to shoot this down like a paper airplane over a AA battery.

Online TrevorMonty

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #53 on: 12/16/2014 09:15 PM »
Just a question if anyone can answer this. adding together the weight of the magnet, weight of power supply and storage,  would it be simpler and lighter to make a carbon fiber or fiberglass reinforced mylar parachute? Some sort of way to control the size wouldn't be hard. The force total on the magnetic brake was maximum 10N and a area of 100m according to IEPC-2011-304 paper. It doesn't say mass of the system though.
 I'm thinking something like 100 grams a square meter will be 1000kg for a 100m parachute to use the upper atmosphere. That arbitrary number for mass is heavy, but it illustrates the point in that the mass of the parachute for high altitude braking might be lighter than a magnetoshell.

I am of course also thinking the parachute will be durable enough to handle hypersonic atmosphere due to the low pressure and density of the atmosphere.

please feel free to shoot this down like a paper airplane over a AA battery.
The magnetoshell is designed to reduce or eliminate a heat shield during reentry or aerobraking. Parachutes can't be used for reentry, the forces are to great.

 NB this experiment is using a cubesat to test technology, if it works it could be used on larger vehicles eg planetary probes,  2nd stages, OTV.

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #54 on: 12/17/2014 08:29 AM »
okay I think I got this mixed up with a different aerobraking system which is used as a end of life system rather than travel aerocapture.
http://www.clyde-space.com/video/lets_put_brakes_spacejunk_problem

I skimed through this paper where I got the idea of a parachute. Though it seems to be more of a sail than parachute.
 http://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCgQFjAB&url=http%3A%2F%2Fmsnwllc.com%2FPapers%2FMAC_IEPC-2011-304.pdf&ei=tUqRVLuLJMP0OrXcgcAN&usg=AFQjCNFuMwdi_giJcbhQwEciWL9r_eAZJA&sig2=McUdQ72w7uOeSl_BDVo2WQ

 I would not think of a parachute as a retry method but using the thin upper atmosphere for aerobraking might still be useful.

Offline MP99

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #55 on: 12/17/2014 09:05 AM »
Just a question if anyone can answer this. adding together the weight of the magnet, weight of power supply and storage,  would it be simpler and lighter to make a carbon fiber or fiberglass reinforced mylar parachute? Some sort of way to control the size wouldn't be hard. The force total on the magnetic brake was maximum 10N and a area of 100m according to IEPC-2011-304 paper. It doesn't say mass of the system though.
 I'm thinking something like 100 grams a square meter will be 1000kg for a 100m parachute to use the upper atmosphere. That arbitrary number for mass is heavy, but it illustrates the point in that the mass of the parachute for high altitude braking might be lighter than a magnetoshell.

I am of course also thinking the parachute will be durable enough to handle hypersonic atmosphere due to the low pressure and density of the atmosphere.

please feel free to shoot this down like a paper airplane over a AA battery.

See the illustration in post #1. Since there is a plasma involved, temps will be very high.

Ultimately, this will be dissipating a huge amount of kinetic energy in a small amount of time. The beauty of doing it magnetically is that the magnetic field restrains the plasma without having to contact matter. It takes extreme measures to enable matter to survive contact with the plasma of re-entry, IE a heatshield.

cheers, Martin

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #56 on: 12/31/2014 05:25 AM »
Martin,
Exactly the issue. For Aerocapture, the forces are not the primary concern, its the heat and control. The hypersonic incoming gas particles deposit massive amounts of energy into the thin upper layer of physical heat shields resulting in heating, vaporization, and worse, sputtering (atoms ripped off above a few eV). A plasma can take the incoming kinetic energy, in fact when the energy is high enough it in theory it will actually help fuel and inflate the Magnetoshell. We also like the idea that you can dial in the force by adjusting the magnetic field based on the actual planetary conditions when you arrive (i.e. the duststorms on Mars).
We see this as a companion to traditional heatshields. The Magnetoshell to capture, the heatshield to enter and descend. In total the system is much lighter.
This last year MSNW built up CubeSat compatible plasma injectors, power supplies, and magnet systems. Here is a picture of a Magnetoshell being generated by a 20 W plasma injector in a 6U CubeSat 'simulator' hanging in our vacuum facility.
Enjoy!
-David

Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #57 on: 01/07/2015 04:36 PM »
Very cool, David!

Online TrevorMonty

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #58 on: 01/07/2015 04:47 PM »
Martin,
Exactly the issue. For Aerocapture, the forces are not the primary concern, its the heat and control. The hypersonic incoming gas particles deposit massive amounts of energy into the thin upper layer of physical heat shields resulting in heating, vaporization, and worse, sputtering (atoms ripped off above a few eV). A plasma can take the incoming kinetic energy, in fact when the energy is high enough it in theory it will actually help fuel and inflate the Magnetoshell. We also like the idea that you can dial in the force by adjusting the magnetic field based on the actual planetary conditions when you arrive (i.e. the duststorms on Mars).
We see this as a companion to traditional heatshields. The Magnetoshell to capture, the heatshield to enter and descend. In total the system is much lighter.
This last year MSNW built up CubeSat compatible plasma injectors, power supplies, and magnet systems. Here is a picture of a Magnetoshell being generated by a 20 W plasma injector in a 6U CubeSat 'simulator' hanging in our vacuum facility.
Enjoy!
-David
When is the demo cubesat mission due to fly.

Offline Burninate

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #59 on: 06/03/2015 07:19 PM »
Let's say I have a ~1000 ton titanium alloy cylinder (good to ~600K) with a pointy end on one side and engines on the other, 15 meters diameter by 75 meters height, on an Earth-Mars Hohmann transfer orbit.

I want to do a direct entry at Mars pointy end forward because the engines are bad with pressures in this direction (not necessarily true, but for the sake of argument...).  I want it to eventually be moving at <1km/s relative to the ground, engine-end forward.

Is MAC capable of that sort of thing?  What sort of mass & volume of MAC should I expect that to require, as a ballpark estimate (1T, 3T, 10T, 30T, 100T, 300T)?  What power & weight laws does MAC obey while scaling to large sizes?  At what sort of velocity does it cease to be effective?

Secondarily:  Can one MAC unit be reused on a multi-phase EDL, with aerocapture, two or three aerobraking passes, and then an EDL?  Or would it have to pop out a new unit every time?
« Last Edit: 06/03/2015 07:21 PM by Burninate »

Offline Joffan

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #60 on: 11/16/2015 09:23 PM »
Magnetoshell news has been a bit lacking recently, for a technology with such exciting potential.

Any updates from the Altius team here on tests, scheduled tests, flights, cooperative efforts etc?
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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #61 on: 11/26/2015 04:54 AM »
Magnetoshell news has been a bit lacking recently, for a technology with such exciting potential.

Any updates from the Altius team here on tests, scheduled tests, flights, cooperative efforts etc?

Unfortunately I don't have any new news to share re: magnetoshell development. Altius and MSNW struck out on both of the MAC-related SBIR Phase II proposals we submitted this spring, and MSNW (who invented the technology and owns the underlying IP) has been crazy busy this year. They landed a ton of contracts this year for their plasma thrusters and fusion energy research and development, and spooling up for those has required their full attention. Since magnetoshells are not Altius's technology to market/sell, I've been trying to be careful not to push it too much without their permission. I'm hoping this will change in the future though, because I agree with you that this is a really promising technology.

~Jon
« Last Edit: 11/26/2015 04:58 AM by jongoff »

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #62 on: 02/09/2016 01:01 AM »
In one of these threads there was talk about injecting an alkali seed into the incoming plasma. From Jon's original article 2 on MHD:
"Thoughts on Maximizing the Effectiveness of MHD Reentry TPS:
...
3. Use an alkali seed. As velocities decrease, it gets harder and harder to maintain the electrical conductivity in the plasma at a high enough value to maintain useful levels of Lorentz interaction. This is similar to the challenge with MHD electric generators. In order to keep the conductivity high, injecting an alkali metal into the stream can help. Alkali metals, particularly Potassium and Cesium have very low ionization energies compared to air. In a weakly ionized plasma, most of the atoms are actually not atomized–almost all of the conductivity is provided by the small number of atoms that are. So, a little bit of seeding can go a long way. This helps you keep your magnetic deceleration forces high even as altitude and velocity drop. The other nice thing about seeding, is that depending on what the fluid is, it might also cut down on the radiative heat transfer from the hot shock layer back to the heat shield.
..."
I saw this "Long Penetration Mode" for counterflowing jets on NBF: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000348.pdf
http://nextbigfuture.com/2016/01/charles-bombardier-has-improved.html
Is something like this a good injection mechanism or is the atmosphere too tenuous at high reentry altitudes to allow for a decent counterflow?

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #63 on: 02/09/2016 03:48 AM »
Alkali jet might be hard. You could always just put a disk of potassium on top of the center of the conventional heat shield. I suppose if you covered the disk with lead, you keep the potassium from igniting in humid air, but light reentry heat will melt off the protective layer. Hrm, maybe not a disk but a telescoping penetrating rod, like a forward aerospike?

Offline Hanelyp

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #64 on: 02/09/2016 01:54 PM »
Potassium would ablate very rapidly.  And really, the need for the extra protection of the magnetic standoff decreases as the reentry vehicle slows.

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #65 on: 05/13/2016 09:17 PM »
I'm not sure if this is the thread to put this in, but NIAC just selected MSNW for a Phase II award for Magnetoshell Aerocapture:

http://www.parabolicarc.com/2016/05/13/nasa-funds-magnetoshells-growable-habitats-statis-technology/

and:

http://www.nasa.gov/feature/magnetoshell-aerocapture-for-manned-missions-and-planetary-deep-space-orbiters

Altius isn't involved in this one, as it's a continuation of MSNW's original work. But I'm still super excited for Dave Kirtley and his team. This is a neat technology, and I'm glad they're getting another $500k to push the underlying theroetical work further. Thankfully, NIAC allows you to rebid a Phase II if you don't win it on your first try, so even though they didn't get selected for further funding on their original work, things can hopefully start moving again. I'd love to see this get flight demonstrated (and sooner rather than later).

W00t!!!

~Jon

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #66 on: 05/13/2016 10:07 PM »


I'm not sure if this is the thread to put this in, but NIAC just selected MSNW for a Phase II award for Magnetoshell Aerocapture:

http://www.parabolicarc.com/2016/05/13/nasa-funds-magnetoshells-growable-habitats-statis-technology/

and:

http://www.nasa.gov/feature/magnetoshell-aerocapture-for-manned-missions-and-planetary-deep-space-orbiters

Altius isn't involved in this one, as it's a continuation of MSNW's original work. But I'm still super excited for Dave Kirtley and his team. This is a neat technology, and I'm glad they're getting another $500k to push the underlying theroetical work further. Thankfully, NIAC allows you to rebid a Phase II if you don't win it on your first try, so even though they didn't get selected for further funding on their original work, things can hopefully start moving again. I'd love to see this get flight demonstrated (and sooner rather than later).

W00t!!!

~Jon

Could you maybe persuade Dave to drop a post here, about how they feel and what they expect?

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #67 on: 05/13/2016 11:14 PM »
Could you maybe persuade Dave to drop a post here, about how they feel and what they expect?

He's probably crazy busy right now, but I'll mention the suggestion. He is an NSF forum member here, but he doesn't post often.

~Jon

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #68 on: 05/13/2016 11:37 PM »
Thanks Jon, saw your retweet of the Geek Wire article - good news.

Quote from: GeekWire
MSNW’s magnetoshell aerobraking system gets in on NASA’s way-out research funding https://t.co/MT088s5cuq

I've got to admit I'd really like some experimentally-minded launch company to try this out in the context of deorbiting an upper stage, on a suitable mission. At least at demonstrator scale. It would make a huge difference to Mars and other interplanetary missions.
« Last Edit: 05/16/2016 04:54 PM by Joffan »
When I say "Jump!", you say "To which orbital inclination?"

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #69 on: 05/14/2016 03:11 AM »
Thanks for the ping, Jon.
MSNW is pretty excited about this program, it’s definitely a unique concept and if the physics and engineering continue to work at scale, it could impact many of the deep space science missions.

In short, we have had two small (Phase I) programs. The first NIAC showed the basic mission analysis looks promising and a small scale experiment that showed we could capture a high speed jet. Promotionally, that was a 1000X increase in drag of a supersonic gas jet with a magnetized plasma over just the physical drag. Scientifically, there is much more work to be done to understand complex gases (atmospheres, molecules) and hypersonic gas interaction. Unfortunately, those tests really require and orbital test. The second program, a Phase I engineering study with Altius, looked at the feasibility of all of the various engineering subcomponents. That looked promising as well, we built a small cubesat geometry, RF plasma injector, and did much of the thermal and electrical design.

That said, there are some big outstanding questions we need to prove. In Phase II we are doing more analytic, system, orbital, and plasma physics modeling to understand the potential limits of this method of Aerocapture. The biggest challenge is that we only have rough physics modeling for how these interactions (and thus effective diameter and drag coefficients) scale with orbital velocity and atmosphere composition. Right now the modeling shows this works best (and maybe only) at very large orbital velocities (elliptical or worse re-entry). And there are outstanding particle physics questions about complex molecular atmospheres that we only guess at.

The part of this Phase II we are most excited about is the ultra-hypersonic testing we are going to do. Rather than have a stationary ‘shell and a flowing jet, we are going to launch a magnetized plasma dipole at 10-20 km/s (20,000-40,000 mph) into a stationary background atmosphere made up of the molecular mixtures for Mars, Neptune, perhaps Pluto. All in a big vacuum chamber. To my knowledge, this is the first time anyone has measured these types of interactions. We should also learn if this technology is applicable for slower re-entries like upper stages.

As part of NIAC, we will have public talks so I will try to get themposted on this thread as they come up.

Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #70 on: 05/14/2016 04:15 AM »
Very exciting, Dave! I wish you and MSNW lots of success with this project!

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #71 on: 05/14/2016 10:07 AM »
Hi Mr Kirtley - what is the power source used for this system, and how much is power a limiting constraint on what it can do?

Offline Robotbeat

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #72 on: 05/14/2016 01:42 PM »
Hi Mr Kirtley - what is the power source used for this system, and how much is power a limiting constraint on what it can do?
Yes.
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Online KelvinZero

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #73 on: 05/14/2016 02:08 PM »
I was wondering if you could generate current from the plasma stream, as in an MHD generator, to power the drag. Any principle say that hope can be easily discarded?

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #74 on: 05/14/2016 04:47 PM »
Hi Mr Kirtley - what is the power source used for this system, and how much is power a limiting constraint on what it can do?

The power can be provided by any onboard power source, provided they have enough power and energy capacity. Unless you're using superconducting electromagnets, the magnetic field to contain the magnetized plasma is pretty power intensive. IIRC for their first pass Mars analysis, to break a 60mT spacecraft into Mars orbit (with the dynamic pressure about 10x higher than what is traditionally used for aerobraking), they needed like 100-115kW, and the discharge durations tend to be on the order of 3-10min depending on the planet in question. In MSNW's designs from their NIAC Ph1 they assumed high power Li-ion or Li-Po batteries, because you only need it for a modest duration, so stored power makes a lot of sense. The other option that seems to make sense to me is some sort of combustion or fuel cell APU if you have chemical propellants on-board.

~Jon



Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #75 on: 05/14/2016 04:58 PM »
There was an ESA test (that somehow never happened) that was going to use MHD to provide (part of) the charge. So it was some sort of self charging via induced currents. I don't know what happened to that project. I thought it was a good a idea.

Offline IRobot

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #76 on: 05/14/2016 06:14 PM »
The other option that seems to make sense to me is some sort of combustion or fuel cell APU if you have chemical propellants on-board.
Mercedes Diesel engine? :)

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #77 on: 05/14/2016 08:01 PM »
The other option that seems to make sense to me is some sort of combustion or fuel cell APU if you have chemical propellants on-board.
Mercedes Diesel engine? :)

I was thinking more along the lines of the GOX/GH2 piston engine APU that ULA is doing for IVF.

~Jon

Online TrevorMonty

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #78 on: 05/14/2016 09:47 PM »
Hi Mr Kirtley - what is the power source used for this system, and how much is power a limiting constraint on what it can do?

The power can be provided by any onboard power source, provided they have enough power and energy capacity. Unless you're using superconducting electromagnets, the magnetic field to contain the magnetized plasma is pretty power intensive. IIRC for their first pass Mars analysis, to break a 60mT spacecraft into Mars orbit (with the dynamic pressure about 10x higher than what is traditionally used for aerobraking), they needed like 100-115kW, and the discharge durations tend to be on the order of 3-10min depending on the planet in question. In MSNW's designs from their NIAC Ph1 they assumed high power Li-ion or Li-Po batteries, because you only need it for a modest duration, so stored power makes a lot of sense. The other option that seems to make sense to me is some sort of combustion or fuel cell APU if you have chemical propellants on-board.

~Jon
That is <20kw/hr for 60mt vehicle. So <100kg of batteries, probably closer to 50kg.

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #79 on: 05/15/2016 01:35 AM »
Its probably possible to capture some of the energy via MHD generators, essentially if you imagine a cylindrical magnet/spacecraft any charge-exchanged particles that pass through the middle magnets can be converted. The intercepted particles outside of the magnet are just captured (drag only). When we did a back of the envelope it was much easier to just use off-the-shelf batteries rather than cryogenic superconductors. Now, if someone works up an efficient, non-superconductor MHD generator . . . .

Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #80 on: 05/15/2016 01:38 AM »
Its probably possible to capture some of the energy via MHD generators, essentially if you imagine a cylindrical magnet/spacecraft any charge-exchanged particles that pass through the middle magnets can be converted. The intercepted particles outside of the magnet are just captured (drag only). When we did a back of the envelope it was much easier to just use off-the-shelf batteries rather than cryogenic superconductors. Now, if someone works up an efficient, non-superconductor MHD generator . . . .
Makes sense, Dave. Thanks for the reply! With the power levels needed, batteries should be simple enough. If this works as well as hoped, this could be quite a game changer.

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #81 on: 05/15/2016 05:47 AM »
Mr Kirtley, two questions

First is their any possible arrangement of the magneto-shell relative to the incoming air-stream that has the potential to generate lift in addition to drag?  My understanding of the interaction between the two is that the shell can only produce drag because incoming air is not deflected laterally by the shell but rather absorbed so any arrangement in which the center of mass and drag are linked by tether the tether will be brought in-line with the flow and no lift will be generated.  Lift would be of great value in moderating the g-forces involved in a capture so I'm hopeful such a thing is possible, have you done any theorizing or testing in this direction?

Second have their been any estimates of how a magneto-shell would impact the possible trajectories of Solar-Electric Propulsion vehicles shuttling between Earth and Mars.  If such a vehicle could brake at destination planets rapidly and without damaging it's solar-wings (I'm thinking they could be angled edge-on to the flow and held by guy-wires) then it should allow for huge savings in both time and propellant due to a more hohmann like trajectory as well as avoiding down-spiraling to low orbits.  Optimal ISP would be lowered and this would cascade into lower electrical demands, higher thrust and faster transit times, possibly into a range competitive with chemical propulsion.  If not perhaps try to bounce it off some of the SEP developers and see what they want to model it.
« Last Edit: 05/15/2016 08:29 AM by Impaler »

Offline MP99

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #82 on: 05/15/2016 06:14 AM »
The other option that seems to make sense to me is some sort of combustion or fuel cell APU if you have chemical propellants on-board.
Mercedes Diesel engine? :)

I was thinking more along the lines of the GOX/GH2 piston engine APU that ULA is doing for IVF.

~Jon
If you're carrying that much cryogenic liquid, couldn't you just use it to chill down superconductors instead just before entry interface?

Cheers, Martin

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #83 on: 05/15/2016 10:38 PM »
Great questions on power. When we did the initial concept study, we had a lot of challenge getting the system and missions to close, the power levels were just too high. Neptune missions are 10's of kW and HEOMD are 100's of kW and a large amount of that energy goes into heating of the Magnets. We had to do the actual orbital modeling to calculate the effective 'burn time'. As trevor suggested, even 100 kW for a few minutes can be done by modern batteries. You then have a system trade of magnet thermal and battery mass compared to 1) Hall thrusters (X3!), PPUs, and big arrays for gentle deceleration or 2) physical aeroshells for Aerocapture.
« Last Edit: 05/15/2016 10:52 PM by dkirtley »

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #84 on: 05/15/2016 10:51 PM »
Impaler, we just don't know the dynamic behavior of these type of systems yet. You are right that this doesn't act like a deflector/deflection shield and more like a volumetric parachute (the ion deceleration should be happening throughout the volume of the magnetoshell rather than at the surface like a normal parachute or ballute). In theory you could still steer the drag somewhat by shaping the magnetic field and impart side loads, plane changes, trajectory steering, etc. Also, because we can make these so much bigger than a physical shield (I don't know how big the ballute designs are getting, probably pretty big), you get more drag, earlier in the injection/descent so the peak dynamic pressure and deceleration forces are lower. There are still big outstanding questions about stability as well as the dynamics of the total configuration, some of which MSNW hopes to answer through modeling and the experiment in this NIAC program. I don't think anyone has put much thought into tethered or multi-body systems, yet. Any thoughts on what you could  do with 2 or more of these 'volumetric parachutes' on tethers, each with a time dependent variable size?

Offline Impaler

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #85 on: 05/15/2016 11:44 PM »
It sounds like the volumetric parachute matches my thoughts on how the system behaves.  Under that understanding I had already tried and rejected a few configurations designed to produce lift on thought experiment basis.

First I considered two or more magnetos on tethers dragged behind the vehicle with some variation is size or shape between them such that they flank the payload rather then follow directly behind it and can exert torque on the payload (this might require a rod or repulsion effect between the two shells to keep them from colliding), but realized that this will always sum to a center of drag behind the vehicle center of mass and the two centers would always be drawn to a strait line configuration with the flow which is clearly a no lift configuration. 

I then considered the possibility of variation in time, increasing drag on one shell so that the center of drag is displaced once again from the strait line configuration.  This would cause the vehicle to once again re-orient itself and if drag was varied fast enough it's conceivable that a continuous off center drag could be produced and a continuous spinning or gyrating of the payload at the end of the tether might be produced.  A simpler means to achieve the same ends would be to just have 3? rigid arms deployed from the payload with magnetos at the ends of these which vary in power output over time, but this would put the arms under bending stress rather then the tensile stress of a tether and this would certainly be more massive as a result.  If we wanted to gain or lose angular momentum from the vehicle though this looks like it would work, though I don't see any immediate application for it.

The question is if this actually produces any lift or not and I'm inclined to believe it doesn't on conservation of momentum basis because the wake shouldn't experience any lateral deflection.  But their is one small chance of drag and that's if the shell is performing a net pick-up and drop off of gases from one portion of the wake to another even if all the gas remains in a strait line flow.  But I suspect that the mass of gas displaced in this way is so minuscule as to have only infinitesimal amounts of lift.

The only sure fire solution I could come up with is to shape the main payload mass at the end of the tether in such a way that it acts as a single forward canard, this might require some kind of large deploy-able surface like ADEPT, but designed  to be completely asymmetrical and with a relatively low need for heat resistance.  If the vehicle is intend on performing a full EDL it's likely to be designed with some lift generating shape for the lower atmosphere anyways so the question is if it can produce a worthwhile amount of lift when in the thin upper atmosphere.

Without having to actually figure out lift it should be possible to run simulations with arbitrary L:D ratios added in to see what effect they have.  Try a few broad ratios 100:1, 50:1, 20:1, 10:1 to get an idea of how much benefit it actually provides and if it's really worth pursuing aggressively.
« Last Edit: 05/16/2016 05:43 AM by Impaler »

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #86 on: 05/16/2016 02:26 AM »
The other option that seems to make sense to me is some sort of combustion or fuel cell APU if you have chemical propellants on-board.
Mercedes Diesel engine? :)

I was thinking more along the lines of the GOX/GH2 piston engine APU that ULA is doing for IVF.

~Jon
If you're carrying that much cryogenic liquid, couldn't you just use it to chill down superconductors instead just before entry interface?

Cheers, Martin

You don't need much propellant to run even a 100kW APU for ~5min. But theoretically if you had propellant for that, you could have propellant for chilling a superconductor, especially if you have a LOX/LH2 stage like ACES. Lots of ways of skinning the cat, but with the amount of power IVF produces, you can do a non-superconductor electromagnet on ACES that can produce a magnetoshell in the 50-100m diameter range (if I'm remembering my calculations correctly)...

~Jon

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #87 on: 05/16/2016 05:34 PM »
So because this technology works with plasma, it's best for thin upper-atmospheric conditions. Could it ever be suitable for upper stage recovery? Like, for example, could this tech somehow be refitted onto the upper stage of F9R, to help it "fly" back for a hoverslam? Could it even help lower stage for RTLS? Musk has previously said that he views flying as simply a matter of achieving particular L/D numbers, regardless of how they are achieved. So would  magnetoshell be able to achieve the required L/D to assist reusability/recovery?

Is magnetoshell being investigated for Mars EDL, since Mars has that taller and much thinner atmosphere? If the magnetoshell approach was used for Mars EDL, would it be able to significantly reduce your retropropulsion requirements, and by how much? In what ways could this translate into improvements for the MCT/BFS?
« Last Edit: 05/16/2016 05:41 PM by sanman »

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #88 on: 05/16/2016 09:19 PM »
So because this technology works with plasma, it's best for thin upper-atmospheric conditions. Could it ever be suitable for upper stage recovery? Like, for example, could this tech somehow be refitted onto the upper stage of F9R, to help it "fly" back for a hoverslam? Could it even help lower stage for RTLS? Musk has previously said that he views flying as simply a matter of achieving particular L/D numbers, regardless of how they are achieved. So would  magnetoshell be able to achieve the required L/D to assist reusability/recovery?

Is magnetoshell being investigated for Mars EDL, since Mars has that taller and much thinner atmosphere? If the magnetoshell approach was used for Mars EDL, would it be able to significantly reduce your retropropulsion requirements, and by how much? In what ways could this translate into improvements for the MCT/BFS?

I think up-thread Dave mention that the testing they'll do in Phase II will help them determine if MAC could be used for EDL applications. The problem is that a lot of the physics gets more complicated when you get to higher atmospheric densities and slower speeds. I'm optimistic that MAC could at least simplify orbital reentry/recovery, but Dave is always trying to keep me from getting too enthusiastic about it for Mars or Earth EDL applications, before they have more testing/analysis to support such claims. :-)

One thing to keep in mind (also discussed up-thread) is that it isn't clear yet if MAC can provide useful lift. Which means worst, case you may have to assume a ballistic flight profile (albeit a ballistic flight profile with a very low and actively controllable ballistic coefficient).

~Jon

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #89 on: 05/17/2016 11:41 AM »

One thing to keep in mind (also discussed up-thread) is that it isn't clear yet if MAC can provide useful lift. Which means worst, case you may have to assume a ballistic flight profile (albeit a ballistic flight profile with a very low and actively controllable ballistic coefficient).

~Jon


So you guys were saying that Magnetoshell seems to behave like a volumetric parachute only, and perhaps doesn't provide deflection necessary for lift.
But magnetic fields can deflect things, bending the charged particles along their field lines. Why isn't that useful deflection? It's just a matter of shape.
(Also, why do you only want to exploit magnetism, as compared to overall Lorentz force?)

Just as an airfoil with the correct shape can re-direct the force of an oncoming flowstream in an orthogonal direction to provide lift, likewise magnetic field lines should also be able to deflect the plasma flow orthogonally, if the field lines have the right shape. Sure, the coupling between the plasma and a magnetic field is weaker and thus it's not an immediate/abrupt deflection like with a solid airfoil surface, but you've got that large volume to buffer/accumulate your interaction anyway.
The analogy to your "Volumetric Parachute" would be the "Volumetric Airfoil".


Seems like you should want to focus on getting the magnetic field lines into the correct contour shape, to effectively do what an airfoil does and provide the lift. And you'd want your field to be acting on a large enough volume to provide enough buffer for interaction because of the weaker coupling.

The volumetric-parachute/pure-drag thing sounds like the basic simple case scenario, and then the lifting-airfoil thing would be the more custom-contoured case.

How does this stuff get tested anyway - in wind tunnels?

And if Magnetoshell is useful for EDL, couldn't it also provide at least a small benefit during ascent as well?
« Last Edit: 05/17/2016 01:17 PM by sanman »

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #90 on: 05/17/2016 05:23 PM »

One thing to keep in mind (also discussed up-thread) is that it isn't clear yet if MAC can provide useful lift. Which means worst, case you may have to assume a ballistic flight profile (albeit a ballistic flight profile with a very low and actively controllable ballistic coefficient).

~Jon


So you guys were saying that Magnetoshell seems to behave like a volumetric parachute only, and perhaps doesn't provide deflection necessary for lift.
But magnetic fields can deflect things, bending the charged particles along their field lines. Why isn't that useful deflection? It's just a matter of shape.
(Also, why do you only want to exploit magnetism, as compared to overall Lorentz force?)

Just as an airfoil with the correct shape can re-direct the force of an oncoming flowstream in an orthogonal direction to provide lift, likewise magnetic field lines should also be able to deflect the plasma flow orthogonally, if the field lines have the right shape. Sure, the coupling between the plasma and a magnetic field is weaker and thus it's not an immediate/abrupt deflection like with a solid airfoil surface, but you've got that large volume to buffer/accumulate your interaction anyway.
The analogy to your "Volumetric Parachute" would be the "Volumetric Airfoil".


Seems like you should want to focus on getting the magnetic field lines into the correct contour shape, to effectively do what an airfoil does and provide the lift. And you'd want your field to be acting on a large enough volume to provide enough buffer for interaction because of the weaker coupling.

The volumetric-parachute/pure-drag thing sounds like the basic simple case scenario, and then the lifting-airfoil thing would be the more custom-contoured case.

[caveat: Dave's the expert, I'm just a semi-educated fan, but I'll try to give an answer based on my best understanding.]

It's more complicated than that. You start with a neutral particle that's nearly at rest relative to the fast moving spacecraft. Once it charge exchanges with an ion in the magnetized plasma, it's now a charged particle at rest relative to moving magnetic field lines, which then cause the charged particle to start spiraling around the field lines in a direction driven by Lorentz Forces. The problem is that after a short period this newly ionized particle will end up charge exchanging with another atmospheric neutral, resulting it in it being neutralized and then flying off in whatever direction it was going in, at whatever velocity it had picked up by that point. The timing of when it has its next collision depends on how dense the atmosphere is and how fast the spacecraft is moving, and the timing has a distribution to it, it's not a precise thing. To make things more complicated once it's been neutralized by that first charge exchange collision, it has the chance of being collided with again before it leaves the magnetized plasma volume. In fact for large MAC volumes, you might very well have a single particle ionized and reneutralized several times between when it first enters the volume and when it finally leaves.

In the end, the momentum transfer is going to depend on the final velocity and direction of the particles as they leave the plasma volume relative to when they entered it. Is there some way to shape the magnetic field such that more particles emit in some off-track direction? Possibly. But it's a really, really non-trivially complex problem to model, since you're talking about interactions of huge numbers of particles. Unless I'm missing something.

Quote
How does this stuff get tested anyway - in wind tunnels?

Mostly in vacuum chambers--we're talking hypersonic flow regimes that tend to be really hard to mimic in a wind-tunnel. Dave hinted above at his super-hypersonic tests they're looking at doing in this Phase II.

Quote
And if Magnetoshell is useful for EDL, couldn't it also provide at least a small benefit during ascent as well?

Huh? How?

~Jon

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #91 on: 05/17/2016 06:32 PM »
Hi, thanks for the great reply


[caveat: Dave's the expert, I'm just a semi-educated fan, but I'll try to give an answer based on my best understanding.]

It's more complicated than that. You start with a neutral particle that's nearly at rest relative to the fast moving spacecraft. Once it charge exchanges with an ion in the magnetized plasma, it's now a charged particle at rest relative to moving magnetic field lines, which then cause the charged particle to start spiraling around the field lines in a direction driven by Lorentz Forces. The problem is that after a short period this newly ionized particle will end up charge exchanging with another atmospheric neutral, resulting it in it being neutralized and then flying off in whatever direction it was going in, at whatever velocity it had picked up by that point. The timing of when it has its next collision depends on how dense the atmosphere is and how fast the spacecraft is moving, and the timing has a distribution to it, it's not a precise thing. To make things more complicated once it's been neutralized by that first charge exchange collision, it has the chance of being collided with again before it leaves the magnetized plasma volume. In fact for large MAC volumes, you might very well have a single particle ionized and reneutralized several times between when it first enters the volume and when it finally leaves.

In the end, the momentum transfer is going to depend on the final velocity and direction of the particles as they leave the plasma volume relative to when they entered it. Is there some way to shape the magnetic field such that more particles emit in some off-track direction? Possibly. But it's a really, really non-trivially complex problem to model, since you're talking about interactions of huge numbers of particles. Unless I'm missing something.

So that kind of sounds like "mean free path" - how long you typically go without bumping into something.

Since it's a "control volume" rather than a "control surface", I guess you can't really talk about a "boundary layer" for flow separation, but surely there are certain geometries (cusps?) that would be more conducive to throwing off the particles in particular directions, ejecting/expelling them from the field.

Quote
Mostly in vacuum chambers--we're talking hypersonic flow regimes that tend to be really hard to mimic in a wind-tunnel. Dave hinted above at his super-hypersonic tests they're looking at doing in this Phase II.

Cool - when does Phase II happen?

Quote
Quote
And if Magnetoshell is useful for EDL, couldn't it also provide at least a small benefit during ascent as well?

Huh? How?

~Jon

How about when you're ascending through the upper atmosphere? Maybe it would be better for a scramjet traveling at high Mach for prolonged period.

Somebody should bring this idea to Elon Musk, because it sounds like it would be great for his MCT. Imagine if they spend all that time and effort developing MCT, and then this Magnetoshell thing comes out soon afterwards, and shows huge performance advantages they missed at on.
« Last Edit: 05/17/2016 07:02 PM by sanman »

Offline JasonAW3

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #92 on: 05/17/2016 06:57 PM »

Quote
Quote
And if Magnetoshell is useful for EDL, couldn't it also provide at least a small benefit during ascent as well?

Huh? How?

~Jon

How about when you're ascending through the upper atmosphere? Maybe it would be better for a scramjet traveling at high Mach for prolonged period.

I think that you misunderstand the purpose of the Magnetoshell.  it INCREASES drag to slow down and protect the craft using it.  Unfortunately, this means that it would likely increase drag for any craft trying to use it to go hypersonic.
« Last Edit: 05/17/2016 06:57 PM by JasonAW3 »
My God!  It's full of universes!

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #93 on: 05/17/2016 07:08 PM »

I think that you misunderstand the purpose of the Magnetoshell.  it INCREASES drag to slow down and protect the craft using it.  Unfortunately, this means that it would likely increase drag for any craft trying to use it to go hypersonic.

Well, I get that it produces drag - it's meant for reentry deceleration in upper atmosphere - but I thought it could be used for steering as well.

But, gee, I wonder how much it could radically improve MCT? Maybe MCT wouldn't have to be as fat, like some are saying it will be, since a magnetoshell could provide instant virtual ''fatness" or drag on demand.
« Last Edit: 05/17/2016 07:12 PM by sanman »

Offline JasonAW3

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #94 on: 05/17/2016 07:24 PM »

I think that you misunderstand the purpose of the Magnetoshell.  it INCREASES drag to slow down and protect the craft using it.  Unfortunately, this means that it would likely increase drag for any craft trying to use it to go hypersonic.

Well, I get that it produces drag - it's meant for reentry deceleration in upper atmosphere - but I thought it could be used for steering as well.

But, gee, I wonder how much it could radically improve MCT? Maybe MCT wouldn't have to be as fat, like some are saying it will be, since a magnetoshell could provide instant virtual ''fatness" or drag on demand.

That might be an option, but as Boeing owns the patent, I seriously doubt that SpaceX would use it or be allowed to use it.
My God!  It's full of universes!

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #95 on: 05/17/2016 07:41 PM »
That might be an option, but as Boeing owns the patent, I seriously doubt that SpaceX would use it or be allowed to use it.

Ouch - that's too bad - that's like patenting the tokamak or the parachute :(

Good thing Goddard didn't patent everything

Man's biplanetary future is hostage to patents :(
« Last Edit: 05/17/2016 07:46 PM by sanman »

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #96 on: 05/17/2016 08:06 PM »

Well, I get that it produces drag - it's meant for reentry deceleration in upper atmosphere - but I thought it could be used for steering as well.


Why?  There is no issue with steering.  Why add another system that is only useful for one or so minute of flight during ascent when there is a perfectly good one with gimbaling engines.

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #97 on: 05/17/2016 08:07 PM »

Ouch - that's too bad - that's like patenting the tokamak or the parachute :(


No, not the same. 

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #98 on: 05/17/2016 09:04 PM »
So that kind of sounds like "mean free path" - how long you typically go without bumping into something.

Since it's a "control volume" rather than a "control surface", I guess you can't really talk about a "boundary layer" for flow separation, but surely there are certain geometries (cusps?) that would be more conducive to throwing off the particles in particular directions, ejecting/expelling them from the field.

Yeah, it seems like it might be possible, but at least for now I've been assuming it's a pure drag device until proven otherwise. Controlled lift would be huge though for a wide range of applications if they can get that through field shaping.

Quote
Cool - when does Phase II happen?

No idea--Dave would have to answer that. But they just barely announced the NIAC Phase 2 late last week, so we're probably talking a minimum of at least 2-4 months from now till they have a contract negotiated and work started.

Quote
Somebody should bring this idea to Elon Musk, because it sounds like it would be great for his MCT. Imagine if they spend all that time and effort developing MCT, and then this Magnetoshell thing comes out soon afterwards, and shows huge performance advantages they missed at on.

I can't speak for Dave, but I've heard from a wide range of sources that SpaceX has a bit of a history of... "in-housing other people's ideas", so I hope he treads carefully, and protects his IP well.

But I agree that MAC, if it scales as expected, could have huge impacts for in-space transportation architectures envisioned by SpaceX, ULA, NASA, and other groups.

~Jon

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #99 on: 05/17/2016 09:07 PM »

I think that you misunderstand the purpose of the Magnetoshell.  it INCREASES drag to slow down and protect the craft using it.  Unfortunately, this means that it would likely increase drag for any craft trying to use it to go hypersonic.

Well, I get that it produces drag - it's meant for reentry deceleration in upper atmosphere - but I thought it could be used for steering as well.

But, gee, I wonder how much it could radically improve MCT? Maybe MCT wouldn't have to be as fat, like some are saying it will be, since a magnetoshell could provide instant virtual ''fatness" or drag on demand.

That might be an option, but as Boeing owns the patent, I seriously doubt that SpaceX would use it or be allowed to use it.

Boeing doesn't own a patent on Magnetoshell Aerocapture. MAC is an MSNW-developed technology. I don't know where MSNW stand as far as IP protection on that so far, but I don't think Boeing has anything to do with it. I do hope though that MSNW does a good job of securing their IP, as I think this could be a pretty enabling technology for a lot of players. And good IP protection on legitimately innovative technologies can encourage other players to play nice.

~Jon

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #100 on: 05/18/2016 12:37 AM »
I can't speak for Dave, but I've heard from a wide range of sources that SpaceX has a bit of a history of... "in-housing other people's ideas", so I hope he treads carefully, and protects his IP well.

But I agree that MAC, if it scales as expected, could have huge impacts for in-space transportation architectures envisioned by SpaceX, ULA, NASA, and other groups.

~Jon

Well, I remember getting the impression that Dragon's LAS/powered-landing feature was suddenly announced after Boeing unveiled CST-100 with its pusher LAS.

I don't see how SpaceX can expect to invent every single useful technology it needs to conquer Mars. There are naturally going to be some good technologies belonging to others that will be invaluable to them, that they'd be better off licensing. This definitely sounds like one.

But this technology seems like it could even be used for steering hypersonic missiles, etc - so it would be militarily sensitive, too.

Boeing doesn't own a patent on Magnetoshell Aerocapture. MAC is an MSNW-developed technology. I don't know where MSNW stand as far as IP protection on that so far, but I don't think Boeing has anything to do with it. I do hope though that MSNW does a good job of securing their IP, as I think this could be a pretty enabling technology for a lot of players. And good IP protection on legitimately innovative technologies can encourage other players to play nice.

~Jon

It seems like MCT is being built with today's technologies, but there are budding technologies like Magnetoshell which could totally outclass the existing technologies of today, so as to render MCT obsolete once they become available.

Magnetoshell sounds like something that you'd design your entire spacecraft around, starting from a clean sheet.
Just like how an electric car doesn't have to be constrained to the same architecture as a traditional combustion engine car.
If MCT could use Magnetoshell, then it might look completely different than what they're currently planning.


What about this experiment? How much does it overlap with the Magnetoshell Aerobraking idea?

http://www.universetoday.com/46474/the-next-generation-of-heat-shield-magnetic/

It's specifically meant as a heat shield, so it's not really intended to provide drag or lift - just to keep that superheated shock front away from the re-entering spacecraft, so it's a somewhat different intent.

Yet it seems plausible that you could have a single system that does both, providing the Magnetoshell Aerobraking and also providing the Magnetic Heat Shield.

It also seems like a Magnetic Heat Shield is that tougher/toughest case that you were talking about, whereby you're dealing with denser medium, higher temperature, etc from the compressed shock front.
« Last Edit: 05/18/2016 12:39 AM by sanman »

Offline Jim

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #101 on: 05/18/2016 02:17 AM »

But this technology seems like it could even be used for steering hypersonic missiles, etc - so it would be militarily sensitive, too.


No, there is no reason for it on hypersonic missiles, they already have fins and control surfaces (which work in subsonic, transonic, supersonic and hypersonic regimes), why add another system and power source to accomplish a task that is already taken care of. 

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #102 on: 05/18/2016 05:04 AM »
It seems like MCT is being built with today's technologies, but there are budding technologies like Magnetoshell which could totally outclass the existing technologies of today, so as to render MCT obsolete once they become available.

While I agree that something like MAC is something you'd want to incorporate early into something like MCT, do you really think they're going to be that far into serious design work for MCT by the time this Phase 2 wraps up in two years? It's not like they're bending metal or even at PDR status right now. 

~Jon

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #103 on: 05/18/2016 05:52 AM »
I see MCT being a rather conventional conic landing vehicle initially which is then paired with a large cargo-carrying SEP transit vehicle. 

The SEP vehicle would carry the Magneto-shell for braking at Earth and Mars, with Argon propellant loaded at both ends of the transit leg and only the boost into transfer orbit costing propellants the ratio of propellant to useful payload that needs to be boosted to orbit each cycle would be >80%.  It would be best for transporting cargo which is then loaded into the landing vehicle in mars orbit.  A bit like how trucks and giant container ships work together.

It's an effective way to combine a landing capsule vehicle of fairly normal present day tech (basically a huge Dragon capsule) while leaving room for big game-changing in-space propulsion tech for the future when volume is actually large enough to justify it's development and use.

Offline Burninate

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #104 on: 05/18/2016 03:22 PM »
I suspect the only chance MCT has of single-synod-reuse with two-way fast transit, is once it has MAC on both ends and some substantial propellant production infrastructure prelanded at the Mars surface station.

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #105 on: 05/18/2016 04:37 PM »
I suspect the only chance MCT has of single-synod-reuse with two-way fast transit, is once it has MAC on both ends and some substantial propellant production infrastructure prelanded at the Mars surface station.

Trying to do Mars colonization without lots of ISRU infrastructure and aerocapture technology seems to be getting the cart miles before the horse.

The nice thing is that neither of these things seem like huge cost-drivers. You could probably get MAC and large-scale Martian ISRU to TRL 9 for less than 1% of the cost of developing the rest of the transportation infrastructure for serious Mars settlement.

~Jon

Offline sanman

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #106 on: 05/18/2016 05:46 PM »
What also seems nifty about MAC is that it could be highly adjustable - it could be totally reconfigured for the differing conditions of Earth EDL vs Mars EDL. It could be a one-size-fits-all aid.

What are the limitations of Magnetoshell's benefits? Taken to its logical extreme, suppose you have some ideal superconductive setup, with a very strong power source. Suppose there's no human/biological payload onboard, so you don't have to worry about any danger to them from a very strong magnetic field.

To what extent could Magnetoshell protect a vehicle from re-entry harshness to allow you to use a lower-Mach aerobody with more fragile structures? The idea would be that those more fragile structures could be more advantageous for lower-velocity maneuvering near the ground, but would need protection from the harsher conditions of re-entry. Or maybe you could have mass savings from using less rugged structures.

To what extent could MAC aid reusability?
« Last Edit: 05/18/2016 05:49 PM by sanman »

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #107 on: 05/18/2016 06:38 PM »
What about this experiment? How much does it overlap with the Magnetoshell Aerobraking idea?
http://www.universetoday.com/46474/the-next-generation-of-heat-shield-magnetic/
Quote
RE: Compressional heating, ionization, or shock heating
There have been lots of concepts and studies that take advantage magnetic interaction with existing space plasmas. MHD decelerators and heat shields try to take advantage of the high density, low temperature, low ionization fraction, mm-long mean free path plasma that is created during shock heating during reentry. Magnetic sails, mini-magnetospheres, and plasma magnets take advantage of the low density, high temperature, high ionization fraction, km+ mean free path solar and interstellar wind.

While the pictures are similar, the physics are quite distinct, MAC is taking advantage of very high altitude planetary atmospheres with meter-long mean free path, low density, and high temperature (velocity) neutrals. The key is to capitalize on the gas effects that happen in the semi-collisional or kinetic particle regime, essentially there are many gas particles, but they are still at a low enough density that they acting like billiard-balls, rather than fluids. This is called Charge Exchange Ionization (CEX), where an ion and neutral collide, they swap an electron (charge), but not momentum. This is a dominant effect in plasma thrusters. After a CEX you can act (drag) on the newly ionized particle with a weak magnetic field, no superconductors or km-wide magnets required. More to follow, but this requirement brackets the altitudes and velocities where MAC works.
Lubos has a nice write-up.
https://www.particleincell.com/2011/charge-exchange/

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #108 on: 07/15/2016 02:01 PM »
Plasma physicist here. What orientation of the magnetosphere relative to the direction of travel works best?  I'm guessing that side-on might result in less need for shielding the north & south poles of the craft, but head-on could have a larger drag cross-section.

Also, the ionization fraction in the upper atmosphere is probably pretty small. Is there a need to 'seed' the plasma in the magnetic shell?
« Last Edit: 07/15/2016 02:08 PM by Solo »

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #109 on: 07/16/2016 02:45 AM »
Yes I believe their is a plan to do some seeding to get the process kick-started faster.  I don't know how orientation effects things but the process is a momentum and charge exchange collision, I'd hope you could help tell us how this works.

Offline guckyfan

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #110 on: 07/16/2016 01:02 PM »
My understanding was that the magnetic field is trailing the vehicle. like a parachute. But my understanding is limited. Take it with a tablespoon of salt or two.

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #111 on: 07/24/2016 11:03 PM »
A Magnetoshell (as opposed to a magnetosphere) is not designed to interact with the very limited ionized atmosphere. The focus of this concept is to work on the atmospheric neutrals though charge exchange with a pre-existing and pre-magnetized plasma population. This new approach came about precisely because at all altitudes there is significantly higher neutral density than ion density in a planetary atmosphere. Even during re-entry. Thus any magnetosphere or MHD approach will be neutral-collision dominated for ionization/recombination, transport, and magnetization. When we took our old magnetosphere concepts and applied them to aerobraking, as opposed to a solar wind, radiation, or ion beams, the classical plasma physics assumptions totally broke down and the entire approach had to be reworked.

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #112 on: 07/24/2016 11:05 PM »
As to orientation, a great and unanswered question. As these magnetic geometries don’t actually shield, but trap charged particles there is no significant increase in shielding based on direction of orientation. For the case where the spacecraft is embedded in the magnetic field, the field directs just as many particles Into the spacecraft as away. This, btw, also applies to any of those radiation shielding concepts.

We do think that it will work better with the pole orientation into the ‘wind’. For a short coil dipole geometry (ie google ‘magnetic dipole’) the magnitude of the field extends further in the wings than on axis. Just like you said, an effective larger drag cross section. That said, there will be some field line stretching, so the resulting geometry is still unknown (but we are working on modeling it).

Another question, do you think it is better to tow this (like a huge parachute) or put your spacecraft in it?
« Last Edit: 07/24/2016 11:08 PM by dkirtley »

Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #113 on: 07/25/2016 03:52 AM »
Very informative, thank you David!

Offline MP99

Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #114 on: 07/25/2016 04:33 AM »


For the case where the spacecraft is embedded in the magnetic field, the field directs just as many particles Into the spacecraft as away. This, btw, also applies to any of those radiation shielding concepts.

...

Another question, do you think it is better to tow this (like a huge parachute) or put your spacecraft in it?

David,

Many thanks for a series of informative posts.

For a spacecraft carrying cryogens, is there an option to embed the magnetic coils in / near those tanks so they could be cooled down to superconducting temperatures? Would this give much benefit?

Cheers, Martin

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #115 on: 07/25/2016 08:33 AM »
dkirtley:  Any thoughts on what the upper limits of entry velocity if any that such a system could handle when scaled up, or any upper limit on how much velocity can be bleed off in a single aerocapture pass through a planetary atmosphere such as at Earth or Mars.  Are limits more likely to be G loads on the vehicle and it's squishy contents or some limitation in the devices ability to exert a braking force?

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #116 on: 07/26/2016 12:15 AM »


For the case where the spacecraft is embedded in the magnetic field, the field directs just as many particles Into the spacecraft as away. This, btw, also applies to any of those radiation shielding concepts.

...

Another question, do you think it is better to tow this (like a huge parachute) or put your spacecraft in it?

David,

Many thanks for a series of informative posts.

For a spacecraft carrying cryogens, is there an option to embed the magnetic coils in / near those tanks so they could be cooled down to superconducting temperatures? Would this give much benefit?

Cheers, Martin

Would this imply something like embedding superconductor tapes into a carbon fiber winding for a carbon fiber tank?

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #117 on: 07/26/2016 08:06 PM »
dkirtley:  Any thoughts on what the upper limits of entry velocity if any that such a system could handle when scaled up, or any upper limit on how much velocity can be bleed off in a single aerocapture pass through a planetary atmosphere such as at Earth or Mars.  Are limits more likely to be G loads on the vehicle and it's squishy contents or some limitation in the devices ability to exert a braking force?

The limit is actually a lower limit. These particular physics effects only work above a certain energy. A good way to think about it is two slow moving particles just bounce off each other (excitation), if they are moving faster they can actually swap an electron (charge exchange), and if they are moving faster still they can knock an electron entirely off (impact ionization). For an Earth type atmosphere, we think the lower limit where this technology works well is 8 km/s and the upper limit is 18 km/s. There will still be drag effects below and above these velocities, but we don't know how well it would work yet. Our mission studies we are focused on the really high delta-V missions, like interplanetary orbit insertion and lunar/Mars return missions.

You definitely still have the G-force and dynamic pressure issues (and squishy payloads), but because your 'shell is so much bigger than a standard physical aeroshell, you can do the same total braking maneuver at higher altitude and over a longer period. In theory, 10X lower peak forces and 1000X lower heating.

Anyone have other weird missions fit in this kind of velocity range?


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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #118 on: 07/26/2016 11:56 PM »
Not sure if this is a tangent, but how applicable is this for an e-sail spacecraft that is doing interplanetary insertion?

Offline Burninate

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #119 on: 07/27/2016 04:38 AM »
Not sure if this is a tangent, but how applicable is this for an e-sail spacecraft that is doing interplanetary insertion?

For an Earth type atmosphere, we think the lower limit where this technology works well is 8 km/s and the upper limit is 18 km/s.

A prototype e-sail uranus / gas giant mission assumes about 30km/s entry velocity and expects to survive that with a high mass fraction heat shield - https://arxiv.org/pdf/1312.6554v2.pdf

What's the expected failure mode of MAC above 18km/s?

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #120 on: 07/27/2016 11:18 PM »
Not sure if this is a tangent, but how applicable is this for an e-sail spacecraft that is doing interplanetary insertion?

For an Earth type atmosphere, we think the lower limit where this technology works well is 8 km/s and the upper limit is 18 km/s.

A prototype e-sail uranus / gas giant mission assumes about 30km/s entry velocity and expects to survive that with a high mass fraction heat shield - https://arxiv.org/pdf/1312.6554v2.pdf

What's the expected failure mode of MAC above 18km/s?

For the deep planets where the atmosphere is Hydrogen and Helium (rather than N2), the upper limit is much higher, 40+ km/s. If the incoming velocity is too high, your particle collisions ionize, rather than charge exchange. You'd still get alot of drag, but the dynamics of the plasma gets much more complicated as you sweep up large amounts of atmosphere and loose energy to the ionization processes.

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #121 on: 07/28/2016 08:01 PM »
Thanks David! That sounds like a fun project.  If you haven't already, you should talk to Michael Mauel at Columbia Univ. about his dipole confinement research.  Also, the FRC guys (Tri-Alpha, John Slough at Helion) deal with magnetized plasma blobs fired into neutral gas (probably a bit too fast, I saw 1 million mph quoted on the Helion site). I'm guessing you are familiar with their work already though.

Right, I was assuming the coil would be mounted around the perimeter of the conical capsule.  The disadvantage there is that you need shielding both on the top and bottom of the craft, though. (Assuming the mean free path of the ions before a charge exchange collision is longer than the bounce time in the mirror field.) I guess it depends on how much reduction you get in the heat load due to (a) the reduced peak heat flux (b) any improvement in the dissipation of the energy into the escaping particles instead of into the craft.  The 'parachute' coil would improve (b) for sure.  Probably a trade-off in terms of engineering to make sure it deploys correctly, gets power, cooling, etc.

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #122 on: 07/28/2016 08:30 PM »
dkirtley:  Any thoughts on what the upper limits of entry velocity if any that such a system could handle when scaled up, or any upper limit on how much velocity can be bleed off in a single aerocapture pass through a planetary atmosphere such as at Earth or Mars.  Are limits more likely to be G loads on the vehicle and it's squishy contents or some limitation in the devices ability to exert a braking force?

The limit is actually a lower limit. These particular physics effects only work above a certain energy. A good way to think about it is two slow moving particles just bounce off each other (excitation), if they are moving faster they can actually swap an electron (charge exchange), and if they are moving faster still they can knock an electron entirely off (impact ionization). For an Earth type atmosphere, we think the lower limit where this technology works well is 8 km/s and the upper limit is 18 km/s. There will still be drag effects below and above these velocities, but we don't know how well it would work yet. Our mission studies we are focused on the really high delta-V missions, like interplanetary orbit insertion and lunar/Mars return missions.

You definitely still have the G-force and dynamic pressure issues (and squishy payloads), but because your 'shell is so much bigger than a standard physical aeroshell, you can do the same total braking maneuver at higher altitude and over a longer period. In theory, 10X lower peak forces and 1000X lower heating.

Anyone have other weird missions fit in this kind of velocity range?
I have a few weird missions:

How much could we save on mass (not crew) transportation to Neptune or Uranus?  And would it be advantageous in one direction or the other?  Can we basically transform a fly by mission into a stop at mission?

Another fun possibility would be the hypothetical planet 9.  If this is a form of gas giant, then might we use this to stop at the planet rather than do a quick fly bye like New Horizons did over Pluto?

Another is a SEP mission to Mars; could the large area allow us to use aerobraking on a relatively fragile vehicle such as a SEP transport?

And for my personal interest, (and rather off thread, sorry) are mini magnetospheres as radiation protection devices still an active field or has that application been abandoned?

Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #123 on: 07/29/2016 01:54 AM »
Also, the FRC guys (Tri-Alpha, John Slough at Helion) deal with magnetized plasma blobs fired into neutral gas (probably a bit too fast, I saw 1 million mph quoted on the Helion site). I'm guessing you are familiar with their work already though.
David is the CEO of Helion Energy, which is sort of a spin off of MSNW LLC :)
John Slough is the president and Director of Research at MSNW LLC.
« Last Edit: 07/29/2016 01:57 AM by Elmar Moelzer »

Offline Elmar Moelzer

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #124 on: 08/25/2016 05:35 AM »
Great NIAC presentation by David Kirtley earlier today, showing their progress and future plans for the Magnetoshell Aerocapture:
http://livestream.com/viewnow/NIAC2016/videos/133838016
His presentation starts about 50 minutes into the video.
« Last Edit: 08/25/2016 05:36 AM by Elmar Moelzer »

Offline guckyfan

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #125 on: 08/25/2016 06:22 AM »
Very interesting and promising technology. They are talking now about a 6U cubesat to demonstrate it in space.

Offline redliox

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #126 on: 09/08/2016 07:36 PM »
How much power does MAC require?  I've read through as much of this thread as I could and still don't have a specific answer.  Something on the level of kilowatts seem to be implied.  If that's the case I see problems but I also get hints there are variables not unlike how aerocapture itself has to deal with the variables of air pressure and density.

Assuming killowatts, that's slightly steep for a probe to spit out.  With solar power, it'd be a piece of cake at Venus and (with slightly more difficulty) Mars to get this.  However, at Uranus and Neptune, where the need to bleed off speed to enter orbit is in greater demand of this tech, sunlight isn't an option.  The average output for a standard RTG is just over 200 watts per unit; and there's factoring in plutonium decay which (using info on New Horizons' RTG) is about 5% powerloss every 4 hours.  I don't think a mission lofting enough plutonium to output a full kw would be launched; Cassini and Galileo both received protests for their 500+ w supplies.

On the plus side, I've seen commentary here about how, like with regular aerocapture, the setup only needs to be on for a matter of minutes to function.  That would make the power supply problem easier to handle; there have been suggestions for the Europa lander to give it a chemical generator (said by commentators here, not the mission designers bear in mind); in the case of a Neptune mission my concern would be if it would expire like a car battery does after ~6 years v.s. the likely 9 years of flight.

Mainly I'm curious how much power MAC needs; any other fresh news on it would be a bonus.
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Offline qraal

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #127 on: 09/10/2016 12:01 AM »
Anyone have other weird missions fit in this kind of velocity range?

How about a "Snowbank Orbit" mission to Planet Nine? Cruise speed 165 km/s, to aerocapture into orbit?

Offline jongoff

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #128 on: 09/10/2016 03:13 AM »
How much power does MAC require?  I've read through as much of this thread as I could and still don't have a specific answer.  Something on the level of kilowatts seem to be implied.  If that's the case I see problems but I also get hints there are variables not unlike how aerocapture itself has to deal with the variables of air pressure and density.

Assuming killowatts, that's slightly steep for a probe to spit out.  With solar power, it'd be a piece of cake at Venus and (with slightly more difficulty) Mars to get this.  However, at Uranus and Neptune, where the need to bleed off speed to enter orbit is in greater demand of this tech, sunlight isn't an option.  The average output for a standard RTG is just over 200 watts per unit; and there's factoring in plutonium decay which (using info on New Horizons' RTG) is about 5% powerloss every 4 hours.  I don't think a mission lofting enough plutonium to output a full kw would be launched; Cassini and Galileo both received protests for their 500+ w supplies.

On the plus side, I've seen commentary here about how, like with regular aerocapture, the setup only needs to be on for a matter of minutes to function.  That would make the power supply problem easier to handle; there have been suggestions for the Europa lander to give it a chemical generator (said by commentators here, not the mission designers bear in mind); in the case of a Neptune mission my concern would be if it would expire like a car battery does after ~6 years v.s. the likely 9 years of flight.

Mainly I'm curious how much power MAC needs; any other fresh news on it would be a bonus.

Kilowatts and big Lithium-Ion batteries. You only need them to operate for ~5-10min at a time typically, so you can trickle charge them from something with lower power levels like a solar panel or RTG.

~Jon

Offline Joffan

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #129 on: 10/11/2017 02:26 AM »
Was there anything new for the NIAC 2017 session?

https://twitter.com/cant_HALT_me/status/912439326860070912
Quote
David Kirtley of MNSW discusses his research on magnetoshell aerocapture for manned missions and planetary deep space orbiters #NIAC2017
When I say "Jump!", you say "To which orbital inclination?"

Offline eriblo

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #130 on: 10/14/2017 02:55 PM »
Was there anything new for the NIAC 2017 session?

https://twitter.com/cant_HALT_me/status/912439326860070912
Quote
David Kirtley of MNSW discusses his research on magnetoshell aerocapture for manned missions and planetary deep space orbiters #NIAC2017

I haven't kept up enough to know whats new but the presentation is the first 25 min of the day 1 part 4 stream. They've started testing the plasma injector and deployable magnet coil for their 3U Phase II LEO CubeSat Demonstrator and will assemble and test it in a vacuum chamber in the coming year (as well as continue their modeling work).

Offline qraal

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #131 on: 10/27/2017 11:01 AM »
Here's another mission design request for MAC. Flying to Jupiter on a fast elliptical orbit (a~5.2) with a re-entry speed of 60.7 km/s. Relative velocity is thus 48.2 km/s. Want to shave off ~1.5 km/s, thus exiting at 46.7 km/s (59.2 km/s relative to the stars) to enter a highly eccentric ellipse. Can the Magnetoshell do the mission?

Offline matterbeam

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #132 on: 10/27/2017 11:47 AM »
Here's another mission design request for MAC. Flying to Jupiter on a fast elliptical orbit (a~5.2) with a re-entry speed of 60.7 km/s. Relative velocity is thus 48.2 km/s. Want to shave off ~1.5 km/s, thus exiting at 46.7 km/s (59.2 km/s relative to the stars) to enter a highly eccentric ellipse. Can the Magnetoshell do the mission?

Equation at the equator adds a non-negligible +/-12km/s to the relative velocity.
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Offline qraal

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #133 on: 10/28/2017 11:43 AM »
You mean Jupiter's 10 hour rotation rate? Yeah. Means it's moving at 12.5 km/s at the equator. Thus, relative to the stars, one re-enters at 60.7 km/s, but relative to the clouds your speed is 48.2 km/s. Capiche?

Here's another mission design request for MAC. Flying to Jupiter on a fast elliptical orbit (a~5.2) with a re-entry speed of 60.7 km/s. Relative velocity is thus 48.2 km/s. Want to shave off ~1.5 km/s, thus exiting at 46.7 km/s (59.2 km/s relative to the stars) to enter a highly eccentric ellipse. Can the Magnetoshell do the mission?

Equation at the equator adds a non-negligible +/-12km/s to the relative velocity.

Offline dkirtley

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #134 on: 10/31/2017 07:06 PM »
You sure you want a Jovian entry and not a direct Europa(n), etc? What is your final orbit/mission/intercept? Roughly how big of a payload? We are looking at minimum energy, 500 kg direct into Europa missions now.
Thanks!

Offline Joffan

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Re: Magnetoshell Aerobraking & Aerodynamics
« Reply #135 on: 12/04/2017 11:06 PM »
News on another step in this technology:

https://www.geekwire.com/2017/uw-team-wins-nasas-nod-small-satellites-magnetic-braking-systems/

Quote
NASA says it’ll provide resources for a University of Washington research team that’s working on a concept to put small satellites in orbit around other worlds using magnetic interactions.

The concept, known as magnetoshell aerocapture, is one of nine university-led technology development projects winning NASA’s backing under the Smallsat Technology Partnerships initiative.
:
The nine newly selected teams will have the opportunity to establish a two-year cooperative agreement with NASA, through which each university will receive up to $200,000 per year. As part of the agreement, NASA researchers will collaborate on the projects. UW’s team, for instance, has been paired up with Langley Research Center in Virginia.
When I say "Jump!", you say "To which orbital inclination?"

Tags: aerocapture