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Thread: Reusable balloon-lofted or airplane-lofted Eve orbital launch system- is it possible?

  1. #1

    Reusable balloon-lofted or airplane-lofted Eve orbital launch system- is it possible?

    Ok, so I’d like to create a fully reusable Eve launch system. I’d like the launch point for the system to be anywhere on the planet- not just high altitudes where the atmosphere is thinner. I am willing (and already do) to use any number of mods to accomplish this, just so long as the mods are realistic (so no ion-propelled airplanes for me, no thanks!!!).

    I have two plans, both of which involve launching a high delta V, single stage rocket/space plane from a lofted position above most of the atmosphere. I have created single stage, high TWR, high delta-V (6000 m/s-6500 m/s) landers and rocket rovers for reusable Tylo landings already. Actually, the landers/rovers were OVERDESIGNED for Tylo, as after landing, taking off, and reaching orbit, they still have like 1000+ m/s delta-V left over. (Apparently, it only really requires like 5000-5300 m/s delta V for a typical Tylo de-orbit, landing, and re-orbit.)

    ANYWAY, I am reasonably certain that 6000 m/s is enough to easily get into orbit from the upper atmosphere of Eve… Eve orbital velocity is "only" like around 3200 m/s at at an altitude just above the atmosphere, I believe.

    So to loft my single stage, ascent stage to the upper atmosphere of Eve, I see two options really-

    Balloon-launched rocket system- a balloon from the Hooligan labs mod will be used to lift the rocket above most of the atmosphere. The only real issue I have with this mod is that, from what I have seen, the balloons are ridiculously undersized compared to what they would be in reality. I have been told though that I can configure this to a more realistic set of values. The strength of the dirigible approach is that it should be relatively easy to re-attach a landed ascent vehicle- just hover over to it and dock with it… in theory, at least.

    Nuclear powered, propeller-driven aircraft- an aircraft will be used to lift the rocket above most of the atmosphere. The aircraft will be driven using a nuclear reactor (NOT RTGs) and the electric propellers I BELIEVE are included with the Firespitter propeller pack (right?). The aircraft will also be an excellent method to explore the surface of Eve, as it will have unlimited endurance. The biggest issues with the aircraft will be whether it is truly possible to create a practically-sized aircraft that flies on Eve using a nuclear reactor, AND has enough lift left to loft an ascent stage, and also, getting this aircraft to Eve in the first place, as it will be rather large and unwieldy outside of an atmosphere. I’m positive I can find some way of working out a way to get it there, if such an aircraft is in fact possible to build.

    ANYWAY- now that my question has been put into the proper context, here is my question at last - is what I want to do even possible ?! I will have a piloted aircraft or piloted dirigible and piloted rocket that will separate from each other in the atmosphere. If I am piloting the rocket, then what the hell happens to the vehicle I am not actively piloting once I get outside of 2.5 km?! If the stock game does not handle it well, are there mods that can solve any issues (like maybe, this “RemoteTech” mod I have heard of)?

    Thanks for any help you guys can offer!
    Last edited by |Velocity|; 29th September 2013 at 12:44.

  2. #2
    Friendly Neighborhood Mod sal_vager's Avatar
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    I think you'll have to try it to find out as it's not something that players routinely attempt.

    I doubt you can make it fully reusable, expect to have to discard drop tanks at least.

  3. #3
    Capsule Communicator Geschosskopf's Avatar
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    Hooligan's site or the thread about the airship mod has a pic of an Eve SSTO (which I assume means it's fully reusable). It's a bunch of orange tanks each topped by one of the original Circus balloons. You might want experiment using something like that as a starting point. That's what I'm planning to do next chance I get, being how I'm dissatisfied with Extraplanetary Launchpads as a way to make non-SSTO Eve lifters.
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  4. #4
    Quote Originally Posted by sal_vager View Post
    I think you'll have to try it to find out as it's not something that players routinely attempt.

    I doubt you can make it fully reusable, expect to have to discard drop tanks at least.
    I'm sure several people know how this works or has attempted something like this and knows whether its possible with stock or using mods. The question will be, do those people read the forums and hit reply?

    Another option, not fully reusable but at least more reusable than the real life space shuttle, might to have drop-balloons- basically, just jettison the balloon package and then fire the rockets. The space station around Eve could simply keep a large number of balloon packages in stock.

    But yea, when it's possible to create single stage rockets with a delta V of over 6000, I doubt I'll need to use drop tanks at all- but that depends on how high up in the atmosphere the airplane/balloon will really take me. Considering that the orbital velocity just above the atmosphere is 3200 m/s, I doubt I will have to go to extreme altitudes to make 6000 m/s more than suitable. The vast majority (maybe 75%) of the delta V requirement for a traditional Eve launch vehicle is just overcoming the ridiculously thick atmosphere, the balloon/airplane removes that requirement mostly, and that's why I want to use it.
    Last edited by |Velocity|; 27th September 2013 at 14:53.

  5. #5
    I've done a balloon launched non-SSTO and have considered but never tested the electric propeller idea.

    Getting 6Km/sec delta-v out of a rocket without dropping the balloons/wings/whatever may be hard to achieve. Which isn't to say impossible. I did this before the Cirrus envelopes were added, so that may change the feasibility. I got to about 25Km altitude on balloons, and it then took about 5-6Km/sec of delta-V to reach orbit. That probably wasn't an optimal ascent, however, since I was dropping the balloons and had to make sure that I didn't collide with them after dropping them.

    As for the propeller driven idea, yes, Firespitter has electric props. I've never tried using them to gain altitude for a launch, but I've dropped electric UAV style probes onto the celestial bodies that have an atmosphere. I've generally used the non-folding solar panels on the wings for power rather than RTGs, but with the way the propellers and RTGs are balanced, using RTGs is probably viable.

  6. #6
    Quote Originally Posted by Eric S View Post
    I've done a balloon launched non-SSTO and have considered but never tested the electric propeller idea.

    Getting 6Km/sec delta-v out of a rocket without dropping the balloons/wings/whatever may be hard to achieve. Which isn't to say impossible. I did this before the Cirrus envelopes were added, so that may change the feasibility. I got to about 25Km altitude on balloons, and it then took about 5-6Km/sec of delta-V to reach orbit. That probably wasn't an optimal ascent, however, since I was dropping the balloons and had to make sure that I didn't collide with them after dropping them.

    As for the propeller driven idea, yes, Firespitter has electric props. I've never tried using them to gain altitude for a launch, but I've dropped electric UAV style probes onto the celestial bodies that have an atmosphere. I've generally used the non-folding solar panels on the wings for power rather than RTGs, but with the way the propellers and RTGs are balanced, using RTGs is probably viable.
    I'm not really interested in using RTGs, I plan to use a nuclear reactor. Since it will actually be in the atmosphere, and thus it will have access to good heat sink, I can even use a nuclear reactor without a bunch of heat dissipation panels. Probably, I can use the 300 amp, 8 ton reactor from the DSM mod. That one sucks for realistic deep space missions, as it lacks any cooling panels ("requiring" me to put several tons of structural panels over and around it for the proper effect) but for atmospheric use it's realistic to not need those.

    The wings on the rocket don't need to be extreme, just good enough to give me a controlled glide. I need to glide to a spot over my Eve base and then pop some parachutes (or even, a small balloon), but maybe just landing on the landing gear is viable too.
    Last edited by |Velocity|; 27th September 2013 at 16:11.

  7. #7
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    The reactor driven propeller idea seems a bit complicated. Perhaps it's better to look for mods that can give you air breathing nuclear jet engine. So it sucks in air like normal jet, heats it up using the reactor and shoots the hot exhaust out the back for thrust.


    Alternatively instead of a big and heavy reactor you might want consider the kethoelectric generator from the Kethane Pack. It's basically a fuel cell that consumes kethane to produce up to 75E/s. The generator itself is pretty compact and lightweight too.

  8. #8
    Quote Originally Posted by Temstar View Post
    The reactor driven propeller idea seems a bit complicated. Perhaps it's better to look for mods that can give you air breathing nuclear jet engine. So it sucks in air like normal jet, heats it up using the reactor and shoots the hot exhaust out the back for thrust.

    Alternatively instead of a big and heavy reactor you might want consider the kethoelectric generator from the Kethane Pack. It's basically a fuel cell that consumes kethane to produce up to 75E/s. The generator itself is pretty compact and lightweight too.
    Hmm.. I would have assumed that there weren't any mods that actually had nuclear "jet" engines in them. It was hard enough finding mods that added basic nuclear reactors. I'll look when I get the chance... but I'm not that hopeful.

  9. #9
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    Fully reusable on Eve is very ambitious. Heck, getting off Eve is ambitious. It's atmosphere is like trying to fly though molasses and it's gravity well is comprable to Jupiter.
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  10. #10
    I've never even gotten a Kerbal out of Kerbin orbit, so I can't help you with your question. One thing I can tell you, though, is there are some mods that will prevent your craft from unloading. They are the KOs mod an the TT Never unload mod. You need both of them for it to work. You can write a very basic program for Kos and upload it into the RGU on your jettisoned balloons. Then, the TT never unload mod will prevent the balloon form unloading until you are 300Km away from it. By then, the balloon will hopefully be on the ground.

    Kos really isn't that hard to use. I used it for some time and I have absolutely NO programming experience. The only reason I don't us it anymore is that it has conflicts with other mods.
    The program could look something like this:
    ag1 (execute action group one: decouple the balloons and light the rocket engines. You'd remain in control of the rocket)
    wait 1 (wait one second before taking the next step)
    ag2 (decrease balloon buoyancy to zero)
    wait until altitude = x (wait until altitude equals a value you determine)
    ag3 (deploy parachutes)

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