Spaceplane that can reach Minmus LKO

[Bandus]

Greetings! I have been working hard to try to make a space plane that can reach Minmus but I am having multiple problems and am looking for some suggestions. Optionally, if someone has a working space plane that can reach Minmus LKO, dock with a station to deliver crew and return to Kerbin and land I would appreciate the opportunity to see it so I can better understand what I am doing wrong in my own designs. Basically the issues I am having are:

1. The aircraft can get into Kerbin LKO, however, it has no where near enough Delta V to get to Minmus, let alone back. For a rocket I'd add more fuel and engines, however, I feel like the plane really starts losing any semblance of "looking good", not to mention its flight characteristics begin to suffer.

2. Landing is another issue, every attempt to de-orbit the current design I've been working on has resulted in the the plane exploding in the atmosphere due to heat. It was suggested I hold a 20 degree AoA and I tried this, but the plane fought me the whole way and never really got above a 10 degree AoA.

I really appreciate the help!

[Temstar]

Would you consider a two stage craft: a SSTO to carry a manned spacecraft to LKO. The spacecraft then goes to Minmus to do crew exchange, then return to LKO to dock with the SSTO which then lands back at KSC?

The reason being that taking all that wing and landing gear and jets to Minmus is a big waste of delta-V.

[KerikBalm]

FYI, LKO means Low Kerbin Orbit... just like LEO means Low Earth Orbit for real space travel.

Minmus LKO is an oxymoron.

Anyway, The nuke is your friend here, as are the "wet" wings that carry liquid fuel.

The rapiers are also your friend... higher altitude and airbreathing thrust...

Carry just enough oxidizer to get your apoapsis toabout 80 km, and let the nuke do the rest.

This works:

(all stock except for asteroid day mod payload)

This works:

(even better if the cargobay is filled with a LF tank and 400 units of LF)

Even this works without the nukes... since it has a 30% payload fraction, when its in orbit, the payload is more like 60% of its mass (I forget, I'm just guessing here)

 

Simple rocket equation says that with the KR-2L it has 340*9.81*ln (1/.4) = 3056 m/s. if the payload was used as propulsion.

Since I forget what its mass in orbit was... I do know that the payload mass can be over 33% of the takeoff weight 340*9.81 ln (1/.67) = 1,335 m/s  which is enough to go to minmus... but thats a massive underestimation of what it has in orbit (because that would assume it gets to orbit with all the mass it would have on takeoff, and all of that mass except what was in the payload was dry mass)

 

 

 

 

[Val]

I will shamelessly plug my own designs. Edit: Both crafts come with detailed instructions for most efficient launch profiles, and how to deorbit them from an 80 km orbit to land at KSC runway.

The SSTO I-1 Triana Mk.2 (craft) can go to the Mun or Minmus and dock with a station.

Or if you want to try what @Temstar suggests you can use the SSTO Z-2 High-Five Mk.2 (craft) to carry a spacecraft to LKO, that is capable of going to Mun/Minmus.

 

Edited January 14, 2016 by Val
Info

[Evanitis]

1 hour ago, Bandus said:

For a rocket I'd add more fuel and engines, however, I feel like the plane really starts losing any semblance of "looking good", not to mention its flight characteristics begin to suffer.

I believe this is the correct soultion, and you see the problems with it pretty well.

The alternative ways I can think of are refueling the plane on LKO, or building it so that it can detach the lifter part on orbit. You know, technically it's still an SSTO if you only stage stuff once the Pe is above 70k.

[Bandus]

I appreciate the suggestions and ideas. Thank you!

[Vegetal]

There was a challenge in 1.0.4 where I made a mk3 plane capable of landing on Minmus and come back to Kerbin, it used 4 rapiers and 2 nukes.

It also had a big ISRU onboard so it was capable of doing this round trip without refueling on Kerbin.

So yeah, quite possible.

[Wemb]

On 14/01/2016 at 8:37 AM, Bandus said:

2. Landing is another issue, every attempt to de-orbit the current design I've been working on has resulted in the the plane exploding in the atmosphere due to heat. It was suggested I hold a 20 degree AoA and I tried this, but the plane fought me the whole way and never really got above a 10 degree AoA.

I'm utterly rubbish at planes, but the only time I did make a working SSTO, I had no problems at all during re-entry.  Coming in nose first was a disaster - but having the plane pointing 90deg straight up - i.e. with the wing surfaces prograde bled a surprising amount of dV off the plane in the upper atmosphere - much more than you'd expect if you're used to seeing capsules reenter.  And, while it was able to do that, there still wasn't enough air pressure to make the control surfaces and lift cause a problem. I can't remember when I had to put the nose down and start gliding in, but it certainly never blew up due to heat/stress.

Wemb

[Champ]

On 14/1/2016 at 9:37 AM, Bandus said:

2. Landing is another issue, every attempt to de-orbit the current design I've been working on has resulted in the the plane exploding in the atmosphere due to heat. It was suggested I hold a 20 degree AoA and I tried this, but the plane fought me the whole way and never really got above a 10 degree AoA.

Seems to me you just need more control authority (more control surface). My most-used seaspaceplane ssto has pitch-control-surfaces that are totally disabled during the whole mission and are activated just for reentry.

During the ascent, the canards are the only pitch-controlling surface, and i activate the elevons on the back on the craft just for reentry