Eve DSTO Challenge

[psyper]

This is my first challenge of this type so if you have any suggestions to changes of anything below please let me know. Let the games begin!

So anyway - we all know that a SSTO (Single Stage To Orbit) craft is pretty much impossible for Eve without cheating or exploiting loop holes so I was wondering whether it would be possible for a DSTO (Dual Stage To Orbit) craft to get from the surface to Eve orbit using no cheats. I posted in the forums asking if it was possible and a few ideas cropped up and then GoSlash27 suggested that a challenge should be posted and that got me thinking. So here it is.

The Challenge.

1) starting point is from 110km orbit above Eve. (Atmosphere starts at 96.7 so I figured 110 is as low as you can get).

2) land your craft on Eve using whatever means you feel (rockets, 'chutes etc). Craft must carry at least a single Kerbal to the surface and back to orbit again.

3) you can land at any elevation you like but extra kudos for deep atmosphere launches (there will be a leader-board)

4) you are allowed a launch stage - which is basically a lander craft which you can leave behind - you must stage/undock this before lift-off - your height above sea-level is taken from after you stage so no point in building 2.2km tall launch stages! (ideally you want this to be your landing gear, 'chutes and any extra fuel tanks that were used to de-orbit).

5) At any point in your ascent you are allowed to drop a single stage - you can have multiple parts decoupling or undock the ship in half with multiple docks but it needs to be all completed within 2 seconds. For the love of god your kerbal needs to be onboard the stage that reaches orbit - no ditching kerbals as ballast! (can't believe that popped in to my head!)

6) Remaining craft needs to reach an orbit of at least 110km ASL ready for an interplanetary transfer craft to rendezvous with the lander where it can either dock with the craft or your kerbal can eva to it. (transfer craft not required to complete this challenge).

7) Craft must not use any physics cheats such as kraken drives etc. and must be stock. FAR/NEAR is allowed but please point out that you are using these and I will mark your entry as such.

8) You will need to post a video of your attempt or screenshots of your orbit in map mode, your craft in orbit, its descent, it landed on the surface, its separation from the launch stage (to take your height above sea-level), before and after stage separation, back in orbit, the map screen view of your final orbit. Any other screenshots are more than welcome of course

9) Send me your craft file pretty please - I will be adding them all in to a dropbox/google drive and link them here. just pm me and we'll sort something out.

10) May the odds be ever in your favour.

Scoreboards

Smallest to Largest Massed Craft (after launch stage) - depending on what way around you look at it the highest and lowest craft on this scoreboard are both awesome!

1)

Lowest Height Above Sea-Level (after launch stage)

1)

Most Prettiest\Awesome Ship (Just for the heck of it!)

1)

Edited October 15, 2014 by psyper

[Pds314]

What if we land the craft, then drive up to >7 km altitude via a crawler rover? Is it the launch altitude or landing altitude that counts?

[Gravaar]

What if we land the craft, then drive up to >7 km altitude via a crawler rover? Is it the launch altitude or landing altitude that counts?

Read rule 3

the closer to sea level on launch the higher it scores

[GoSlash27]

I'm excited to see how this one turns out, but I can't participate right now. I'll run some numbers on the problem and see what pops out...

Best,

-Slashy

[Vaporo]

I think I saw someone make an Eve sea-level SSTO ion glider. No cheats, nothing. Just an ion-powered plane. I'd have to find it again to be sure, though.

[psyper]

What if we land the craft, then drive up to >7 km altitude via a crawler rover? Is it the launch altitude or landing altitude that counts?

as Gravaar stated its taken from your launch height - although I'm very interested in seeing what a rover launcher would look like - perhaps another board for the most distance travelled between landing and launching...

I'm excited to see how this one turns out, but I can't participate right now. I'll run some numbers on the problem and see what pops out...

Best,

-Slashy

I'm looking forward in what you are going to do for the challenge

[GoSlash27]

psyper,

A couple recommended adjustments to the rules:

1) Either stock aerodynamics or a seperate leaderboard for mods like FAR, etc.

2) Smallest massed craft instead of largest. That's the challenge of it.

Since I can't participate right now, I'd like to post my observations for anyone to take advantage of.

Eve DSTO from sea level looks to me to come down to 2 strategies for a workable vehicle: Conventional upper stage using aerospikes, or ion upper stage, possibly a glider. Anything else looks to incur too much mass penalty for the lower stage.

Assuming a 1t payload to orbit, an aerospike upper stage is going to end up in the 40t region which will make for a huge booster stage, whereas an ion insertion stage will be in the 2-3 ton range and can be lifted to insertion much more easily.

An aerospike upper stage is more conventional but makes for a cumbersome booster. An ion upper stage is riskier and more complicated, but can potentially pay off with a more manageable aerospike booster.

My first choice would be the ion insertion stage with an aerospike boost/ transstage. Makes for a more manageable descent/ lander.

Good luck!

-Slashy

[psyper]

psyper,

A couple recommended adjustments to the rules:

1) Either stock aerodynamics or a seperate leaderboard for mods like FAR, etc.

2) Smallest massed craft instead of largest. That's the challenge of it.

Good luck!

-Slashy

Done and done

I'm accepting entries now

[Tsevion]

Eve DSTO from sea level looks to me to come down to 2 strategies for a workable vehicle: Conventional upper stage using aerospikes, or ion upper stage, possibly a glider. Anything else looks to incur too much mass penalty for the lower stage.

Assuming a 1t payload to orbit, an aerospike upper stage is going to end up in the 40t region which will make for a huge booster stage, whereas an ion insertion stage will be in the 2-3 ton range and can be lifted to insertion much more easily.

An aerospike upper stage is more conventional but makes for a cumbersome booster. An ion upper stage is riskier and more complicated, but can potentially pay off with a more manageable aerospike booster.

I haven't played with the numbers yet, but I was thinking a nuclear upper stage, in the 8t ballpark, with a standard aerospike lower stage... better TWR than ion, while having a solid ISP and packing around 7k of delta-V. Still need 3k-ish dV in the booster stage, but that should be at least theoretically possible... and I think the booster would get it to the height the nuclear is getting better ISP than any conventional rocket (13km-ish on Eve if I'm recalling correctly). Biggest problem is the TWR still being too low to get us out though, possibly some assist from some 48-7S's or an Aerospike to keep TWR high enough?

Another option I could possibly see is going really big, and using a KR-2L based upper stage... slightly lower ISP, but much better TWR than the aero-spike... but that would be a HUGE craft.

[Tsevion]

While going small usually is a good plan, in this case going big worked for me... I used mostly the NASA parts, a KR-2L based upper stage... I got a craft with about 10.5k of delta-V, landed at just under 4000m, and returned to orbit. I'll cut together a quick vid over the weekend. Really the hardest part was making landing gear... what I ended up making only kinda worked... the landing is... unusual.

Craft is stock except for Kerbal Engineer, which obviously has no actual effect on flight characteristics... but with these tight margins readouts are kinda necessary.

[Tsevion]

Alrighty, here's my entry:

Mass at Eve Takeoff: 690t

Launch Altitude: 3850m

Craft file - The Eveblaster VII

All stock, except for Kerbal Engineer, because I need information when cutting margins this tightly.