How cheap are low-tech(panther) spaceplanes?

[Warzouz]

Long ago, (back in 1.0.5), I build a whole line of reusable SSTO rockets with a payload range from 15T to 600T. The next post has charts for cost per ton.

The rocket were not designed to be low tech, but to be cheap to use, easy to fly and to SCALE up.

It's very hard to scale up a SSTO spacesplane but it's really easy to scale up a rocket SSTO. Just add tanks and engines and you're good to go. I build my 600T (payload to LKO) from my 300T in 10 minutes and it worked at the first test.

Obviously, those ships/assemblies are obsolete, but the design can still be adapted to 1.2.2.

 

[Reusables]

I thought I might need some weight over 50t, but just found out that there's no payload part which weighs that much... The most massive part which is neither fuel nor engine is 6.5t passenger crew cabin, as far as I can find. So there's no point for panther spaceplane as spaceship.

 

1 hour ago, Warzouz said:

Long ago, (back in 1.0.5), I build a whole line of reusable SSTO rockets with a payload range from 15T to 600T. The next post has charts for cost per ton.

The rocket were not designed to be low tech, but to be cheap to use, easy to fly and to SCALE up.

It's very hard to scale up a SSTO spacesplane but it's really easy to scale up a rocket SSTO. Just add tanks and engines and you're good to go. I build my 600T (payload to LKO) from my 300T in 10 minutes and it worked at the first test.

Obviously, those ships/assemblies are obsolete, but the design can still be adapted to 1.2.2.

(snip)

I've been looking at it. I really liked it, actually I borrowed some designs and ideas! Probably I'd never come to the concept of recoverable rockets if you didn't post it. Thanks!

It was great, and I guess it should work in current version as well. Though I think my recoverable rocket TSTO is more efficient as it's staged design.  (I could get 380/t with 15t payload) Still it could be the case that lifters work better in 1.2.

Edited April 24, 2017 by Reusables

[AeroGav]

I just flew mine to Duna,  but after landing in two biomes only had enough fuel to get back to Duna orbit.

In career mode you'd want to find a way to refuel this aircraft in low kerbin orbit so you can go home again, as well as properly tour Duna.    Junior clamp o tron on the nose, have two airplanes meet in orbit and transfer the fuel from one to the other?

I love flying on Duna though, amazing views.

 

[Reusables]

3 hours ago, AeroGav said:

I just flew mine to Duna,  but after landing in two biomes only had enough fuel to get back to Duna orbit.

In career mode you'd want to find a way to refuel this aircraft in low kerbin orbit so you can go home again, as well as properly tour Duna.    Junior clamp o tron on the nose, have two airplanes meet in orbit and transfer the fuel from one to the other?

I love flying on Duna though, amazing views.

(snip)

Amazing video! I have a question, why did you limited the throttle during the ascent till 5.6km?

[AeroGav]

5 hours ago, Abastro said:

Amazing video! I have a question, why did you limited the throttle during the ascent till 5.6km?

I guess I wanted to try limiting "drag losses" - stay out of transonic region - till we'd climbed a bit, and also i wanted to see a bit more of the landscape before leaving for good.   But it probably would have been better to just gun it.   I knew i wasn't coming home at that point anyway.           

Now,  how would you go about rescuing Val from Duna orbit?

[Ncog Nito]

I don't know if anyone has thought of this or not, because I am new to the game, but I've found that I have trouble landing planes, period!  So, what I have been doing is getting the plane back over the KSC, cutting the engines, nose diving toward the runway, and then deploying a pair of radial chutes that I have mounted just over the center of mass.  Then I lower the gears, have the SCS on, level the plane out, and basically land it like I lander.  Like I said, I don't know if anyone else does this, but it is most effective.

[Reusables]

1 hour ago, AeroGav said:

how would you go about rescuing Val from Duna orbit?

These comes to my mind.

 

I. Simple & Economic (Unhealthy)

  1. Wait for Duna -> Kerbin transfer window.

  2. Get Val out of the cozy cabin.

  3. (Optional) If the plane has a probe core, point one of the nuke engines to the Val and turn it on. Val should gain reasonable speed with it.

  4. Use jetpack to plot a nice Ike gravity assist to escape Duna and intersect Kerbin. (Ike flyby costs about 400m/s, so doable)

  5. Let Val wait for countless time during the transfer.

  6. Rendezvous and catch Val with rescue ship.

 

II. Fast (ingame time)

  1. Design a seat with Ant engine, which will grant you lots of dv in a small package. (~3km/s)

  2. Attach Spark engine stage to the seat, which will give you extra 3km/s of dv or so.

  3. Design asparagus-staged nuke interplanetary ship to haul the seat above.

  4. Lift the above spaceship to LKO.

  5. Shoot Duna with it. Literally.

     (*Effective when Duna is close / If you unlocked an ion engine, use it instead of Ant/Spark)

 

III. Reusable

  1. Launch a Reusable SSTO with klaw. The same spaceplane with a klaw attached would work.

  2. Reach Duna orbit.

  3. Rendezvous and grab Val's plane.

  3. Tug the spaceplane back to Kerbin. With proper aerobreaking, I think dv needed is about 2.6km/s on LKO. (Considering the increased mass after grabbing)

 

Though, these are just suggestions. Do what you want

[Spricigo]

13 hours ago, AeroGav said:

 Now,  how would you go about rescuing Val from Duna orbit?

I'd go with my typical rescue infrastructure.

Spoiler

My system has:

1. Rover to collect whoever is in the surface and bring then to the launch point at the equator

2. Reusable rocket for the transportation to Duna's orbit.

3.Vehicle for gathering astronauts stranded in orbit

4. Interplanetary transport between Kerbin's orbit and Duna's orbit

5.Kerbin lander

 

However I don’t think you'll have anything similar in place.  It's up to you to put a compete rescue system in place or just send a single trip vehicle to get Val.

In game time don't seems to be a concern, waiting for the next low deltaV interplanetary transfer windows would be ideal. Also since Val is a competent astronaut docking is not necessary if you keep the seats accessible for EVA transfer.

 

[AeroGav]

1 hour ago, Spricigo said:

I'd go with my typical rescue infrastructure.

however I don’t think you'll have anything similar in place.  It's up to you to put a compete rescue system in place or just send a single trip vehicle to get Val.

In game time don't seems to be a concern, waiting for the next low deltaV interplanetary transfer windows would be ideal. Also since Val is a competent astronaut docking is not necessary if you keep the seats accessible for EVA transfer.

 

Yeah she's just going to have to catch up on Netflix for a few years while another transfer window comes around.

I was thinking of sending a probe core, claw, mk1 fuel tank with a spark upper stage and SRB lower.   Given that this aircraft has a dry mass of about 13-14 tons,  one mk1 fuel tank worth of fuel should get the whole thing back to Kerbin from Duna orbit?

[Spricigo]

6 minutes ago, AeroGav said:

Yeah she's just going to have to catch up on Netflix for a few years while another transfer window comes around.

I was thinking of sending a probe core, claw, mk1 fuel tank with a spark upper stage and SRB lower.   Given that this aircraft has a dry mass of about 13-14 tons,  one mk1 fuel tank worth of fuel should get the whole thing back to Kerbin from Duna orbit?

accordingly to http://www.quantumg.net/rocketeq.html 14t dry mass, 2t fuel, Isp 800 results in 1046m/s.

Just running some number: A single Kickback can provide 2km/s with TWR @launchpad 5* and @burnout 17.5*  for a payload of 6t. From there a spark can provide 3km/s with initial TWR 0,33 assuming a dry mass of 2,2t.

I will mess a bit with the idea later, but  I think we are not too far from a reasonable vehicle. Notice that I started with the booster, usually its better to design in reverse order of use.

 

*obviously, thrust limit its your friend

[Spricigo]

@AeroGav I think this https://kerbalx.com/Spricigo/Valiant may be enough to bring Val back. There is room for improvement but I don't care much more even for crafts I use.

Don't worry If some fins explode during ascent don't worry, its part of the procedure.

[Reusables]

Found a use of Panther. It's useful for rockets as well!

This small 'rocket' which lifts 2t to LKO only costs 344.5/t! Also there is room for improvements; I think I already shaved off 22/t, so it will be 322.5/t.

Flies just like other TSTO launch vehicles, with a bit different speed profile.

 

I regret that I hadn't unlocked the Panther...

EDIT: Here's a refined version.

This gave 328/t.

Edited April 29, 2017 by Reusables