Jool One

[Pds314]

It had come to my attention that most engines have 0 ISP at low altitudes. For this reason, this challenge is much, much harder than expected. For the love of all that is holy, use aerospikes.

Goal:

Your challenge is to design a stock, manned vehicle which begins in orbit, dives into Jool, reaches an altitude of under 1 kilometer, and returns to orbit. Previously, this would've been nearly impossible due to the Delta-V requirements imposed by errordynamic drag. Due to errordynamics no longer applying, however, this should be much easier.

You may reach Jool orbit by any means, including hyperedit, infinite fuel, or transfer stages. However, please do not exploit any physics bugs (ladders, K-drives if you can figure out a way to make them work, etc) once in low Jool orbit.

You need not use a single-stage vehicle. In fact, I suspect that most GOLD level entries will be multi-stage vehicles, as making a pure-rocket SSTO on Jool is probably nearly impossible, given engine and tank masses.

Scoring:

Scoring is based on...

BRONZE. For entries that don't make it to 140 kilometers, score is based on altitude.

SILVER. For entries that DO make it to space, but don't make orbit, score is based on orbital speed.

GOLD. For entries that achieve orbit, score is based on the initial mass of the vehicle. Lower is better.

High Scores

GOLD score list:

1.

2.

3.

SILVER score list

1.

2.

3.

BRONZE score list:

1.

2.

3.

Will post entry soon, I have 3 midterms in the next 3 days.

Edited April 29, 2015 by Pds314

[Rfmeijboom]

I think this may be impossible, at 1km height the atmospheric pressure might be so high that all the Engines have an ISP of 0.

[Pds314]

I think this may be impossible, at 1km height the atmospheric pressure might be so high that all the Engines have an ISP of 0.

I doubt that engines will reach zero ISP. Unless squad changed ISP scaling, which wouldn't have been necessary for other changes, and I am pretty sure even 15 ATM wouldn't stop the toroidal aerospike.

[Rfmeijboom]

It has already been shown that most engines already reach 0 ISP before Eve sea level, Jool has 3 times the pressure there.

But perhaps the aerospike has a chance, I didn't think of that one.

[Pds314]

It has already been shown that most engines already reach 0 ISP before Eve sea level, Jool has 3 times the pressure there.

But perhaps the aerospike has a chance, I didn't think of that one.

That's really weird... ISP shouldn't work that way. IRL, there are rockets that attain okay ISP even under high pressure and in liquids.

[goduranus]

It's definitely possible without cheating, but quite tedious

This kind of craft will do it

http://forum.kerbalspaceprogram.com/threads/88655-Stock-Gyroplane-altitude-challenge

The idea is to ascend like a helicopter until an altitude where engines can be fired

Edited April 30, 2015 by goduranus

[Rfmeijboom]

It's definitely possible without cheating, but quite tedious

This kind of craft will do it

http://forum.kerbalspaceprogram.com/threads/88655-Stock-Gyroplane-altitude-challenge

The idea is to ascend like a helicopter until an altitude where engines can be fired

Hmmm, very creative approach, did not think of that either.

[Serassa]

It still is impossible. A heli craft will not be able to lift big enough of a rocket to get back to orbit.

[metaphor]

Aerospikes are the only engines with a nonzero Isp at 0 altitude on Jool. They have an Isp of 65 s there. That means their thrust is about 80 kN, so they can barely carry a small tank of fuel by themselves. I tried making a 900-part aerospike asparagus ship, but only got to about 5 km altitude on Jool. It's way harder than it was pre-1.0.

Maybe the challenge should be how low can you go inside Jool's atmosphere and still make it back into orbit.