Author Topic: VASIMR Engine  (Read 118145 times)

Offline dbooker

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VASIMR Engine
« on: 05/20/2014 05:04 PM »
Anyone have any info on Ad Astra's VASIMR engine and schedule?  Have the abandoned this project?  Have they run into engineering issues?  There are virtually no status updates on their web site.  Look like they are more interested in hydrogen generation and electricity generation using wind.  No updates on flight unit in years.

Offline aceshigh

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Re: VASIMR Engine
« Reply #1 on: 05/20/2014 05:55 PM »
from Wikipedia, this seems to be the last news:

Quote
Testing on the space station[edit]
On December 8, 2008, Ad Astra signed an agreement with NASA to arrange the placement and testing of a flight version of the VASIMR, the VF-200, on the International Space Station (ISS).[24] As of June 2012, its launch is anticipated to be in 2015;[25] the Antares rocket has been reported as the "top contender" for the launch vehicle.[26] Since the available power from the ISS is less than 200 kW, the ISS VASIMR will include a trickle-charged battery system allowing for 15 min pulses of thrust.

Testing of the engine on ISS is valuable because it orbits at a relatively low altitude and experiences fairly high levels of atmospheric drag, making periodic boosts of altitude necessary. Currently, altitude reboosting by chemical rockets fulfills this requirement. The VASIMR test on the ISS may lead to a capability of maintaining the ISS or a similar space station in a stable orbit at 1/20th of the approximately $210 million/year present estimated cost.[12]

Ad Astra held a formal PDR for the VF-200 with NASA on 26 June 2013


so it seems VASIMR development can only move forward after they test it on the Space Station. But that will only (luckily) happen after in 2015.

Offline Burninate

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Re: VASIMR Engine
« Reply #2 on: 05/21/2014 07:41 AM »
I'm rather confused about why we can't run https://en.wikipedia.org/wiki/High_Power_Electric_Propulsion or some other COTS ion thruster option.

Zubrin has in theaccused VASIMR of being essentially a "Wait until advanced propulsion is ready" perennial excuse to delay a Mars mission (and contingent spending) decade after decade, when in reality the math doesn't work out at all, by several orders of magnitude, for the powersource they assume.  It is not in fact an enabling factor for a Mars mission if alpha=100, as demonstrated, instead of alpha=1.  VASIMR has failed to even keep up with competing ion thrusters on actual demonstrated tech specs, and Congress has failed to fund VASIMR at a level consistent with them caring about its immediate success.

So what stops smaller ion thrusters which don't need to be paired with a trickle-charged battery, from being used on the ISS?  Or said batteries, with a large cluster of ion thrusters?
« Last Edit: 05/21/2014 07:50 AM by Burninate »

Offline avollhar

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Re: VASIMR Engine
« Reply #3 on: 05/21/2014 07:53 AM »
The problem with even-lower-thrust engines than VASIMR is that burn times get really long. So you are not in zero-G anymore. Which may or may not disturb some of the scientific experiments which are done in the ISS for precisely that environmental factor.

Offline Burninate

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Re: VASIMR Engine
« Reply #4 on: 05/21/2014 08:26 AM »
1) The microgravity experiments they do are sort of a joke.  Make-work stuff that doesn't really achieve much.  The pointful part of having them up there is to further develop the engineering capacity for human spaceflight.
2) The ISS is already a very vibration-prone structure, due to the number of humans bumping around in it.
3) The need to burn to maintain altitude is and has always been present, regardless of the fact that it is an acceleration that disrupts their microgravity substantially with chemical propulsion.  So far IIRC they do tend to do 1/300th of a G burns for order 30-90 seconds.
3) VASIMR is way overpowered for the miniscule wattage ops has decided they have available to spare on the ISS, so they talk about charging up the batteries and turning them on a small fraction of the day.  The proper way to address this would likely be to fly a few more solar panels.
4) The amount of acceleration we're talking for steady-state thrust is tiny - 0.055m/s per day, about 300mN of thrust, last time I did the back-of-napkin calculations (97m per day lost at 416km altitude presently).  65 nano-G's.  Scarcely distinguishable from 0 G.
5) The acceleration is actually *currently happening*, due to drag against the outer wisps of atmosphere.  This is already a deviation from zero G.  A thruster is needed to *correct this* and lower the acceleration felt.

On page 8 of the September 2004 HiPEP report NASA/TM—2004-213194 says the pre-prototype HiPEP produced 670 mN of thrust at a power level of 39.3 kW using 7.0 mg/s of fuel giving a specific impulse of 9620 s.

If 20kW is available (IIRC VASIMR is getting 5-10), then a HiPEP derivative should be able to solve the reboost problem entirely on order 100-300kg of xenon fuel per year.
« Last Edit: 05/21/2014 08:48 AM by Burninate »

Offline Muska

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Re: VASIMR Engine
« Reply #5 on: 05/21/2014 08:55 AM »
One question: What are the advantages of untested VASIMR engine compared to well tested array of Hall thrusters? Individual Hall thruster is of course weaker than VF-200, but they are very cheap, reliable and they can be stacked into array in parallel.

One comment: As Russians threatened to shut down ISS by 2020 by shutting down Russian chemical propulsion module. This should put some pressure to deliver adequate solar electric propulsion module into ISS. And possibly some additional solar panels in order to increase power production.
« Last Edit: 05/21/2014 08:58 AM by Muska »

Offline Nomadd

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Re: VASIMR Engine
« Reply #6 on: 05/21/2014 11:14 AM »
The problem with even-lower-thrust engines than VASIMR is that burn times get really long. So you are not in zero-G anymore. Which may or may not disturb some of the scientific experiments which are done in the ISS for precisely that environmental factor.
It could be just the opposite if they had the power. Low thrust engines could run continuously, just negating drag and making for a better zero-g environment.

Offline Burninate

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Re: VASIMR Engine
« Reply #7 on: 05/21/2014 02:41 PM »
One question: What are the advantages of untested VASIMR engine compared to well tested array of Hall thrusters?

This is salient in the ISS's role as a laboratory.

Why have we been manning a laboratory for 20 years that's been running on diesel generators, with fuel refilled weekly?  Why are we hooking up an experimental micro-nuclear-reactor being tested in the lab to keep the lights on, when there's been a conventional option of hooking up to the power grid, a utility pole away?

One of the things that lent a bit of credence to the notion that this was all some kind of red herring conspiracy hoax, was when Ad Astra stated their desire to perform testing on the full-scale version on a moonbase before putting it into operation, to get a vacuum and a stable test platform.

Sidenote, I missed this before: The plans Ad Astra have for testing on the ISS involve a miniscule plane-change maneuver, 15 minutes at a time(once per day?) for 6 newtons, not actual drag-cancelling propulsion.  So long as this is their mode of operation, the ISS will require the same degree of chemical fuel for station-keeping.  As such, VASIMR and an array of more conventional ion thrusters are not mutually exclusive.

-Q&A portion of
« Last Edit: 05/21/2014 02:56 PM by Burninate »

Offline A_M_Swallow

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Re: VASIMR Engine
« Reply #8 on: 05/21/2014 03:23 PM »
{snip}
Sidenote, I missed this before: The plans Ad Astra have for testing on the ISS involve a miniscule plane-change maneuver, 15 minutes at a time(once per day?) for 6 newtons, not actual drag-cancelling propulsion.  So long as this is their mode of operation, the ISS will require the same degree of chemical fuel for station-keeping.  As such, VASIMR and an array of more conventional ion thrusters are not mutually exclusive.


When preparing a conspiracy theory always check money.  Ad Astra are a small company doing this with their own money.  They cannot afford a billion dollars worth of space rated solar panels needed for an all day burn.
« Last Edit: 05/21/2014 03:24 PM by A_M_Swallow »

Online halfshallow

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Re: VASIMR Engine
« Reply #9 on: 05/22/2014 05:43 PM »
Zubrin has in theaccused VASIMR of being essentially a "Wait until advanced propulsion is ready" perennial excuse to delay a Mars mission...
Whilst Zubrin seems to endure a certain amount of criticism for his 'calm and measured manner of speech', I've never heard anyone refute the things he claims about VASIMR in the speech you linked. I think he is probably right. And I definately agree with his stance that, whilst we should be developing new (non-hoax) propulsion technology, we shouldn't be waiting for it to be developed before actually exploring space with people.

Online bad_astra

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Re: VASIMR Engine
« Reply #10 on: 05/22/2014 05:49 PM »
Not to go off topic, but putting people in the solar system with chemical rocket upper stages is like settling America with dugout canoes when we've got caravelles on the drawing board. VASIMIR or some other advanced technology is absolutely necessary. Can it be done with out it? Of course, but why not make the investment to do it right.
"Contact Light" -Buzz Aldrin

Online Elmar Moelzer

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Re: VASIMR Engine
« Reply #11 on: 05/22/2014 05:51 PM »
Zubrin just wants to get to mars ASAP, which would be a one shot stunt mission, too expensive to try again for another 60 years... We have done that with the moon. It put the space program on an unsustainable course. NASA is finally trying to leave that course with commercial crew, now so we should not get on it again with a one shot mars mission.

Offline cordwainer

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Re: VASIMR Engine
« Reply #12 on: 05/23/2014 02:23 AM »
Settlement of Americas is a bad analogy. Since most of the early settlement was done by Amerind peoples long before the invention of the Caravel and some of that was done via a coastal route using dugouts. It's very possible we could do Mars exploration with a large enough chemical upper stage capable of carrying sufficient resources for long term settlement. Where advanced propulsion systems like VASIMR and MNSWR come in is to provide the capability for mass transit of materials rapidly to Mars over a wider range of launch windows and allowing for low priority supply missions via a Mars cycler.

 Heavy Lift chemical systems and near term advanced propulsion systems actually complement one another since you need those large upper stages to transport VASIMR and MSNWR liner fusion vehicles to LEO. When considering cost though chemical rockets are cheaper so using them in the meantime until other technologies are fully developed makes sense. In the past I have been critical of Mars "colonization" and Zubrin's Mars-centric views but it's hard to argue against the approach that Elon Musk is taking with his Mars Colonial Transport. With sufficient funding and investment such an approach could work. 

I would also point out that even with the current crop of advanced propulsion systems you wouldn't be able to send people on a continuous basis, you would still be limited to specific launch windows it's just that those windows would be made wider. Your Mars settlement would still have to have a great deal of self-sufficiency regardless of whether your just staying there for a few months or longer due to the limits in payload and launch windows.

Offline Vultur

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Re: VASIMR Engine
« Reply #13 on: 05/23/2014 05:13 AM »
. VASIMIR or some other advanced technology is absolutely necessary. Can it be done with out it? Of course,

These statements are inconsistent.

I don't think there's a problem with using chemical rockets (EDIT: and just accepting long travel times) if you a) bring a solar flare shelter and b) are willing to accept a few percent (like 5% I think) increase in cancer risk decades down the road (by which point medical technology may well mean the risk is much less significant). Also, I think those risks are calculated with the linear-no-threshold model of radiation cancer risk (that's the normal 'regulatory' one) which may well be far too pessimistic.
« Last Edit: 05/23/2014 05:14 AM by Vultur »

Offline A_M_Swallow

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Re: VASIMR Engine
« Reply #14 on: 05/23/2014 09:50 AM »
. VASIMIR or some other advanced technology is absolutely necessary. Can it be done with out it? Of course,

These statements are inconsistent.

I don't think there's a problem with using chemical rockets (EDIT: and just accepting long travel times) if you a) bring a solar flare shelter and b) are willing to accept a few percent (like 5% I think) increase in cancer risk decades down the road (by which point medical technology may well mean the risk is much less significant). Also, I think those risks are calculated with the linear-no-threshold model of radiation cancer risk (that's the normal 'regulatory' one) which may well be far too pessimistic.

And you are willing to pay the extra to launch many more tons of propellant.

Offline cordwainer

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Re: VASIMR Engine
« Reply #15 on: 05/26/2014 06:29 AM »
Are you willing to pay the extra cost in payload for the powerplant necessary to power VASIMR? Space travel costs money, VASIMR is not about saving fuel costs it's about more efficient use of fuel to allow for greater range and continuous thrust over the vehicles flight regime.

Offline Jim

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Re: VASIMR Engine
« Reply #16 on: 05/27/2014 01:20 AM »
1) The microgravity experiments they do are sort of a joke.  Make-work stuff that doesn't really achieve much.  The pointful part of having them up there is to further develop the engineering capacity for human spaceflight.
2) The ISS is already a very vibration-prone structure, due to the number of humans bumping around in it.


And your sources are?

And adding more solar arrays is a non starter
« Last Edit: 05/27/2014 01:22 AM by Jim »

Offline Jim

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Re: VASIMR Engine
« Reply #17 on: 05/27/2014 02:48 AM »

If NASA really does actually really truly want to focus on the asteroid missions for the near term, I'd love to see a VASIMR concept on the front stage with Dr. Chang Diaz organizing the whole show. 


Not going to happen, it would be a conflict of interest and also, it is not the role of the NASA administrator to perform such a role.

Offline docmordrid

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Re: VASIMR Engine
« Reply #18 on: 05/27/2014 05:15 AM »
Wow!  Didn't Werner von Braun play that role... which is designer and administrator?

von Braun was never NASA administrator.

http://en.m.wikipedia.org/wiki/List_of_Administrators_and_Deputy_Administrators_of_NASA

but IIRC he was the first director of Marshall.

DM

Offline ChrisWilson68

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Re: VASIMR Engine
« Reply #19 on: 05/27/2014 05:26 AM »
Wow!  Didn't Werner von Braun play that role... which is designer and administrator?

von Braun was never NASA administrator.

http://en.m.wikipedia.org/wiki/List_of_Administrators_and_Deputy_Administrators_of_NASA

but IIRC he was the first director of Marshall.

Yeah, and more to the point von Braun didn't have his own outside company developing and pushing a particular technology.  That's the conflict of interest Jim was referring to.

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