VASIMR engine

[Northstar1989]

Seeing as Squad has already followed in NASA's footsteps (and worked alongside NASA) in developing the Asteroid Redirect Mission, I was wondering if it would not be conceivable they might do so again, in implementing the VASIMR (Variable Specific Impulse Magnetoplasma Rocket) engine.

http://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket

NASA is currently planning to install a VASIMR engine on the International Space Station in 2015 (next year!)

It would be interesting to see Squad implement it as well.

VASIMR differs from other ion engines in the following ways:

(1) The ability to adjust specific impulse (ISP)- lower ISP for higher thrust, or higher ISP for lower thrust; both utilizing roughly the same amount of power (in-game the ISP setting could be set by a right-click menu or Action Group...)

(2) Scalability- the VASIMR engine can easily be scaled to consume larger amounts of power and generate greater amounts of thrust (useful if Squad implements larger solar panels, or ever adds nuclear reactors). The current line of VASIMR engine being added to the ISS consumes TWENTY times the electricity of the largest Hall effect thrusters, at 200 kw energy-consumption instead of 10 kw energy consumption... Models have been proposed scaling to 2, 20, and even 200 megawatts... (in-game, nothing larger than 200 kW would really be practical without nuclear reactors, however)

(3) Improved Thrust-Weight-Ratio (TWR) compared to conventional ion engines- due to the greatly simplified internals and reduced number of moving parts compared to other ion engines (this comes at the expense of slightly lower ISP and slightly lower efficiency).

(4) Reliance on Argon rather than Xenon propellent. This is a disadvantage, as Argon's lower density requires larger (volume-wise) fuel tanks than for Xenon.

Thus, the specific part I would suggest is a VASIM based on the real-life 200 kw model. Assuming the stock ion thruster is a 10 kw model (As this is the largest conventional ion engines get), it should consume 20 times the the ElectricCharge, be configurable to operate at similar ISP for around 20 times the thrust, or 3/5th the ISP for a 66% greater thrust; and weigh less than 20 times the stock ion thrusters.

It should consume Argon as a propellent, unique from Xenon.

Regards,

Northstar

[Maelstrom Vortex]

You beat me too it.. I love VASIMIR technology.

[LaytheAerospace]

No thanks. Ion engines are already grossly unrealistic, producing thousands of times more thrust per kilowatt than they should. Giving us one that's twenty times more powerful is just insane.

[Skyler4856]

No thanks. Ion engines are already grossly unrealistic, producing thousands of times more thrust per kilowatt than they should. Giving us one that's twenty times more powerful is just insane.

Yeah, because watching a ship burn for hours is a barrel-of-monkeys

[LaytheAerospace]

Yeah, because watching a ship burn for hours is a barrel-of-monkeys

Good point. Let's just make all the engines have 10,000 ISP and 100,000 kN of thrust, right? More fun to go faster!

Condescension aside, in this game realism matters. I'd prefer not to take the least realistic thing in the game and make it even less realistic. Stuff like this seems like the perfect purview of mods, not the stock game.

[The Jedi Master]

Good point. Let's just make all the engines have 10,000 ISP and 100,000 kN of thrust, right? More fun to go faster!

That's a little rude. He has a point. In real life, ion engines aern't really used because burns can take days.

[Dodgey]

That being said LaytheAerospace realism is not a good enough reason to implement a feature or a part by itsself. I mean all this looks like it's another really powerful engine. Not really a niche filler.

[LaytheAerospace]

That's a little rude. He has a point. In real life, ion engines aern't really used because burns can take days.

I don't think it's any ruder than the post I was replying to. Snark at somebody, get snark right back.

That being said LaytheAerospace realism is not a good enough reason to implement a feature or a part by itsself. I mean all this looks like it's another really powerful engine. Not really a niche filler.

I think you misunderstood. I was using realism as a reason not to implement this suggestion. Of course, I'd be thrilled with something that approximated the actual VASIMR, consuming a few hundred kilowatts of power to produce less thrust than a stock ion thruster.

[vosechu]

For what it's worth, there is a beautiful, stock-alike mod set that covers a lot of near future technologies. In particular, the Near Future Propulsion mod. http://forum.kerbalspaceprogram.com/threads/52042-0-23-5-Near-Future-Technologies-Pack-%28updated-20-05-14-modularized-version-of-NFP%29

I hope this helps!

[Skyler4856]

Good point. Let's just make all the engines have 10,000 ISP and 100,000 kN of thrust, right? More fun to go faster!

Condescension aside, in this game realism matters. I'd prefer not to take the least realistic thing in the game and make it even less realistic. Stuff like this seems like the perfect purview of mods, not the stock game.

I think you misunderstood my intent, and sadly took a route of sciolism. My intention were that, at the end of the day, squad is a company, and frankly they would rather entice as opposed to deny. I personally think the current level of thrust is ideal for gameplay purposes.

[LaytheAerospace]

I think you misunderstood my intent, and sadly took a route of sciolism.

Sciolism? Really? That's a bit of a stretch, to say the least.

You casually dismissed my argument, so I casually dismissed your dismissal. Where's the sciolism?

[Dodgey]

No misunderstanding just bad wording and/grammer on my part. I get what you mean and I was simply trying to build on your comment about realism.

[LaytheAerospace]

No misunderstanding just bad wording and/grammer on my part. I get what you mean and I was simply trying to build on your comment about realism.

Ahh, gotcha. My bad!

[Skyler4856]

Sciolism? Really? That's a bit of a stretch, to say the least.

You casually dismissed my argument, so I casually dismissed your dismissal. Where's the sciolism?

By the very nature of the statement it was condescending.

[Northstar1989]

That being said LaytheAerospace realism is not a good enough reason to implement a feature or a part by itsself. I mean all this looks like it's another really powerful engine. Not really a niche filler.

The niche it fills would be the same one as real life- an intermediate ion engine that can provide more usable thrust levels than standard ion engines (and has better TWR), but suffers from reduced ISP as a result.

I never said it should be implemented solely for realism, it does fill a niche in itself- but realism is also a draw. Being able to imitate real proposed mission plans (NASA currently has versions of the Mars "Design Reference Architecture" for future missions which include Solar-Electric Propulsion, which primarily means VASIMR: http://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf) is a bonus in itself...

See this awesome YouTube video on the Constellation Mars Mission Plan, for instance- this guy/girl had a LOT of fun imitating NASA:

As for the thrust, ion engine thrust is up-scaled for gameplay reasons, no doubt. What should be maintained is the *relation* between VASIMR and stock ion engines. That way if they even decide to re-balance ion engines again (like moving their thrust back down to what it was before) they would already know how to adjust the VASIMR engines too...

Regards,

Northstar

[LaytheAerospace]

By the very nature of the statement it was condescending.

Condescending is not a synonym of sciolistic. And I readily admit it was condescending (I even use that word in the original post). Just don't expect an apology for me being condescending in response to your own condescending post.

[LaytheAerospace]

As for the thrust, ion engine thrust is up-scaled for gameplay reasons, no doubt. What should be maintained is the *relation* between VASIMR and stock ion engines.

While I agree on principle, that any VASIMR part should be appropriately scaled to the ion parts, I still feel that this would be too powerful of an engine. It would make more sense if such an engine really did require a nuclear reactor, so they can't be abused on small interplanetary craft.

Really, my concern is that I don't want the game to end up getting balanced around something that's a billion times more effective than anything that exists in the real world. The basic ion thruster already has 400x the thrust of the 200 kW VASIMR (2kN vs 5N), and can run on a pair of RTGs with electricity to spare.

Best to keep that kind of stuff out of stock altogether.

[Tex]

Now people, remember that although realism is a nice point of KSP, it's still a video game. New players, especially, will be thrown by a realistic burn time offered by a realistic Ion engine. I hated using them myself, but now thanks to the beefing up I am working on a few new designs. If you want realism, I believe that part values can be edited, correct?

[Tery215]

It should consume Argon as a propellent, unique from Xenon.

Nah.

Why make a propellant exactly the same as Xenon yet incompatible twoways?

Air is compatible with a large variety of jet engines.

Liquidfuel is compatible with anything that burns (exception, SRB's)

Oxidizer has no purpose but to counter Liquidfuel(????)

Why make a fuel for powering hyperefficient engines when there's already one?

[Northstar1989]

Nah.

...

Why make a fuel for powering hyperefficient engines when there's already one?

To make it harder. To make it a bit more realistic at the same time.

Regards,

Northstar

[Northstar1989]

While I agree on principle, that any VASIMR part should be appropriately scaled to the ion parts, I still feel that this would be too powerful of an engine. It would make more sense if such an engine really did require a nuclear reactor, so they can't be abused on small interplanetary craft.

Really, my concern is that I don't want the game to end up getting balanced around something that's a billion times more effective than anything that exists in the real world. The basic ion thruster already has 400x the thrust of the 200 kW VASIMR (2kN vs 5N), and can run on a pair of RTGs with electricity to spare.

Best to keep that kind of stuff out of stock altogether.

Stock ion engines are OP'd, but so is everything else in KSP. Remember, the solar system is only 10% scale, but you're working with semi-realistic rocket materials and ISP values. That makes for a VERY different picture than real life, where it takes a lot more Delta-V just to get to orbit...

Just because one part is OP'd is not an excuse not to include another part, and appropriately balance it relative to the other parts...

A VASIMR engine that consumes 20 times the electricity of the stock ion engine would basically require large solar panels to run- RTG's wouldn't be practical. This would be as intended. And as for thrust, it wouldn't produce 20 times the thrust- remember it's less efficient. An appropriately balanced thrust for the stock game might be 15/25 kN (for high/low ISP setting, respectively), with better TWR than ion engines...

Regards,

Northstar

[meve12]

Other than Argon consumption, I agree with NorthStar. Maybe make it a 1.25m part and include 1.25m xenon tanks? Like a energy-intensive upgrade over the 909.

[CaptRobau]

I think the VASIMR could be introduced without making it OP and still making it a realistic implementation of the system as we know it now. It's all about power requirement. While a real-life ion thruster can run off the equivalent of two OX-4L solar panels even the smallest version of VASIMR needs massive panels like these:

The bigger, manned version can't even be done with solar panels instead requiring a small nuclear reactor to power them.

Both thus need to add a lot of mass to even function. That reduces a lot of their OPness. The system has a good payoff, but it requires more skill to get it into orbit.

[Northstar1989]

I think the VASIMR could be introduced without making it OP and still making it a realistic implementation of the system as we know it now. It's all about power requirement. While a real-life ion thruster can run off the equivalent of two OX-4L solar panels even the smallest version of VASIMR needs massive panels like these:

http://www.adastrarocket.com/images/OTV-SEP-VASIMR.jpg

The bigger, manned version can't even be done with solar panels instead requiring a small nuclear reactor to power them.

http://upload.wikimedia.org/wikipedia/commons/5/5a/VASIMR_spacecraft.jpg

Both thus need to add a lot of mass to even function. That reduces a lot of their OPness. The system has a good payoff, but it requires more skill to get it into orbit.

It's highly unlikely the devs would ever add a nuclear reactor to the stock game- as much as I would like to see it myself...

They would also need larger solar panels to feasibly represent something the equivalent of the VASIMR-200 with the kind of power consumption you're suggesting... (go bump my thread suggesting larger solar panels if you still think your idea is good)

Regards,

Northstar

[LaytheAerospace]

It's highly unlikely the devs would ever add a nuclear reactor to the stock game- as much as I would like to see it myself...

A compact nuclear reactor is right up at the top of my want list. I dedicate way too many parts to power generation on my space stations. If I could heft up a single 100t power core and be done with it, I'd be thrilled.