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VASIMR Rocket can take you to Mars in 39 days

  1. Apr 8, 2015 #1
    vasimr.jpg Apparently, this news is all over the net. NASA has given a Texas-based company called Ad Astra Rocket a 10 million dollar grant (the money will be given over a 3 year period) to help develop a functional VASIMR rocket (Variable Specific Impulse Magnetoplasma Rocket), which will supposedly take you to Mars in just 39 days. I've attached a photo of the engine design. Here is a link to the company's website - http://www.adastrarocket.com/aarc/VASIMR

    The VASIMR engine will use radio waves generated by two radio wave couplers to ionize noble gases. The first coupler will generate a "cold" plasma using a helicon RF antenna, and the resulting plasma will be narrowed down into a stream using a strong electromagnetic field (generated by a superconductor), and an ion cyclotron heating coupler will then raise the temperature of the ionized mixture to an incredible degree (about 10 million Kelvin, or the same temperature as the Sun's core), and a massive thrust will be produced as the high pressure plasma will be ejected ( although, as the website says, a magnetic "nozzle" will be required to allow linear propulsion) . By precisely controlling ionization levels and electromagnetic field strengths, it is believed that the thrust can be controlled and changed very well (and very quickly too). The engine also boasts an "electrodeless" system and improved fuel efficiency compared to other electric thrusters.

    The biggest challenge with this technology is power supply. The entire mechanism requires huge amounts of electricity, and solar and nuclear power are considered to be the only viable sources of energy to run this engine through space at present.

    The VASIMR engine technology has come under some criticism as well. NASA however, appears to have taken a liking to the design.

    Personally, I think this "wonder" engine seems too good to be true (I'm not an expert in this by any means though). What do you have to say about it?
     
    Last edited: Apr 8, 2015
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  3. Apr 8, 2015 #2

    Dotini

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    The discovery of vast glaciers, thought to be pure water ice, just under the surface of equatorial regions of Mars will lend new encouragement to the quest for the Red Planet.
    http://phys.org/news/2015-04-mars-belts-glaciers-frozen.html

    Although I am skeptical of the safety of manned space flight much beyond low earth orbit, (I wear a belt and suspenders), anything which can reduce travel time to Mars should be investigated.
     
    Last edited: Apr 8, 2015
  4. Apr 8, 2015 #3
    I'd hate to experience those g's...
     
  5. Apr 8, 2015 #4

    Astronuc

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    One important parameter missing in the description of the engine is the thrust (N), or mass flow rate (kg/s). Instead there is only a claim of 'high thrust', which is not informative. A thrust vs power curve would be nice.

    Also, the trip time will depend on the mass being accelerated. The mass will include the capsule, the rocket motor, and the power plant.

    As far as I know, the VASMIR concept has provided little thrust.
    http://www.adastrarocket.com/aarc/technology (VX-200 is designed for 5 N at 200 kW). But has that been achieved, and have they done a 40 to 50 day test.

    I would like to see the design calc and assumptions for a 39 day trip.
     
  6. Apr 8, 2015 #5
    @Astronuc
    Yes, you've definitely got me thinking. I really don't know how they plan on "scaling" up their operations to allow that Mars trip. NASA sure has placed a lot of trust in the company with that 10M bill though..
     
  7. Apr 8, 2015 #6

    Astronuc

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    I should have explicitly mentioned the propellant and propellant storage tanks. Assuming something like hydrogen, methane or ammonia, in liquid form. There is the propellant required to get to the destination, then the propellant required to return - assuming this is roundtrip. A one way trip can be done faster, or with less energy.

    The key performance parameter is kW/kg, or MW/kg.
     
  8. Apr 9, 2015 #7
    Can you please compare the roles of thrust and power to weight ratio for this engine?
     
  9. Apr 9, 2015 #8

    Doug Huffman

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  10. Apr 9, 2015 #9

    mheslep

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    The technical criticisms by Zubrin are unanswered as far I know. A short list includes: i) a short trip is undesirable; it should be 6 months outbound with a lower delta-V because, in case of failure, that allows a big loop return to a place Earth is going to be allowing an Apollo 13 like coast home, ii) the radiation concerns of a longer trip are overblown, equivalent to smoking for some months, iii) VASIMR energy overhead from ionization energies and the like don't allow the high Isp's claimed.

    Zubrin's also offers political speculations that are not provable but also not unreasonable in my view. That being that NASA does not actually want to do a manned Mars mission in the near term without a huge budget that would leave existing rice bowls untouched. VASIMR is not ready yet even according to proponents, unlike a traditional chemical lift to Mars. So too nuclear powered designs. Per Zubrin, these reach technologies are being used as delay tactics.

    None of this is to say research on ion engines or nuclear powered designs should not continue; it should. I contend these higher tech alternatives be considered in a fair technical manner against chemical lifters, for which the price has fallen considerably.
     
    Last edited: Apr 9, 2015
  11. Apr 9, 2015 #10

    mheslep

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  12. Apr 19, 2015 #11

    rollingstein

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    Sounds like a fatal flaw to me.

    e.g. What size of nuclear reactor would be needed? How many MW of electric power needed?
     
  13. Apr 19, 2015 #12

    D H

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    It is 2015, and per the movies I am supposed to be able to pop the hood of my car and see Mr Fusion. All I need to do is add a tiny bit of garbage and voila! out comes 1.21 gigawatts. The only problem: That's pure science fiction.

    If that science fiction was reality, and if VASIMR operated according to theory at those untested power levels, then yes, we could use VASIMR to get people to Mars in 39 days. But Mr Fusion is science fiction, and VASIMR engines have only been constructed and tested at the hundreds of kilowatts level. That's great (maybe) for reboosting the International Space Station.

    The reality is that ion propulsion engines such as VASIMR are power thirsty beasts. Until we know how to produce massive amounts of power without having to use massive amounts of mass, getting humans to Mars in 39 days will remain in the realm of science fiction.
     
  14. Apr 19, 2015 #13
    I follow the manned mission to Mars movement pretty closely, and I think that Chang Diaz or one of his team should have shown up for Zubrin's challenge. Bad form. We are not elitists here, we ostensibly have the same goal and although admittedly Zubrin can be chaffing at times, that's no reason not to show up and defend your project. Mars society is not only a legitimate organization, it's conferences host some of the premier figures in the space exploration field, including many NASA administation, astronauts, university researchers, and characters like Elon Musk and representatives from Virgin Galactic.



     
  15. Apr 19, 2015 #14

    mheslep

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    Valid challenges should best be made and answered in the literature. Zubrin had some valid points imo but they should be addressed in writing. Bad form is attached to Zubrin for public bombast, not his target, regardless of technical validity.
     
  16. Apr 19, 2015 #15
    Well, if you watch the videos, I think Zubrin did address this in print, Spacenews or something like that. I disagree about bad form being attributed to his public bombast. He makes a good point about NASA doing nothing other than going in circles for the last 40 years in terms of their manned space program. The manned space program has devolved into a scattered distribution of pet projects with no focus or cohesion for a targeted mission. It's a bunch of individual greedy researchers painting some pie in the sky nonsense for a 2050 Mars Mission so they can get funding to do some BS local work in the lab and draw 7K a month. IMHO.
     
  17. Apr 19, 2015 #16
    The fact is that we the people are doling out 19 billion dollars a year to fund this charade and somebody's got to call BS on it. Thank god for Zubrin's bombast. I could go into details but just visit the Mars Society website or Youtube channel. We need to engage now in a Mars mission and we can justify funding the ISS for the next ten years if we have that mission engaged. Otherwise, I personally say we cut ISS funding.
     
  18. Apr 19, 2015 #17

    mheslep

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    No, a column or whatever in Spacenews is more shooting his mouth off. By in the literature, I mean the peer reviewed literature. Avoiding the proper forum is bad form, period. As Chang Diaz published in the literature, he owes Zubrin nothing.

    Look, Zubrin can influence policy somewhat by gathering a public following in these public discussions, articulate his encyclopedic knowledge of spacecraft propulsion and mission mechanics and pound the table about it all, insult those with whom he disagrees. At this he's apparently very adept, good for him. Or, he can forego the table pounding and address simply the technical issues, and no more, in the peer reviewed literature. He can't do both at the same time, and for good reason.
     
    Last edited: Apr 19, 2015
  19. Apr 19, 2015 #18

    mheslep

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    That may well be so. I might well support US space spending as Zubrin indicates. That doesn't mean Chang-Dias owes Zubrin or the Mars Society even the time of day.
     
  20. Apr 19, 2015 #19
    Not even the time of day? Why not? Here's a debate Zubrin had with a NASA proponent of solar electric propulsion (SEP) in relation to the proposed asteroid retrieval mission. Zubrin basically lambasted this effort as well but we got both sides and it was an interesting and informative civil discourse. It's not about Chang Diaz owing anything to anybody, it's about him moving through the relevant communities and pushing/defending his program. The fact that he doesn't show up for the premier deepspace/manned mission conference makes me supremely suspect. At the end of day, it really gets down to funding, and that was Zubrin is all incensed about. Make a plan, set a deadline, and issue the funds accordingly. Funding this VASIMR nonsense in the context of the first manned mission to Mars is a hoax. It's should not even be considered as a viable propulsion option until is has payed it's dues in nearer deep space missions, IMO.

     
  21. Apr 19, 2015 #20
    It sounds like a good idea, but the power plant required to run the thing would need to be truly massive in itself.
    I think it would need a low mass source of a huge energy supply to make it work, either by directly converting mass to electrical energy, or having some sort of matter/antimatter annihilation going on. to make it look like an improvement on existing ion engine design.
     
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