Under 10000 fund mission to Laythe's seabed and back

[camacju]

Part 1: Launch

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In VAB, under 10000 funds. Craft contains the Laythe ascent vehicle, ballast tanks/descent module, return module, transfer stage, and booster.

On pad

Launch

Booster burns out

Circularizing. The two Baguette tanks at the front of the craft are ussed to control buoyancy of the Laythe submarine. They launch full and I burn off half the fuel in them to circularize the orbit, which is enough to make the submarine barely sink.

 

Part 2: Journey to Laythe

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Mun assists

Mun flyby 1

Mun flyby 2

Encounter Kerbin 5 years and 4 solar orbits later, get another assist off Mun and eject radially

One year later, encounter Kerbin again and get an Eve encounter for K-E-K-K-J route

Eve flyby

Laythe and Tylo assists

Part 3: Doing stuff at Laythe

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Speed at Laythe encounter is really high so I can't aerobrake directly. I use Tylo, Laythe, and Vall assists to reduce aerobrake speed.

Laythe flyby after Tylo - speed is still too high so I use one more assist before coming back to Laythe

Vall flyby

Now aerobrake is much better

Return module circularizes while submarine descends. I aim for the middle of the DeGrasse Sea because that's pretty deep.

Parachute deployed

Descending

At the seabed, 2723 meters below sea level. I brought a Goo canister so we can see how the goo reacts to these crushing depths.

Back at the surface. Because I wanted this mission to be cheap, I didn't want any unnecessary mass for the floats/ballast tanks, so I used partially filled fuel tanks. I burn off some fuel to change the buoyancy of the submarine.

Part 4: Return trip

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I have some fuel in the tanks - why not use it for the first leg of the ascent? Probably not strictly necessary, but it gives me more margin.

Extra tanks dropped, ascent vehicle continues to suborbital trajectory

The ascent vehicle is designed to put Bill on suborbital trajectory so he can finish with the EVA pack.

Bill detaches the empty fuel tanks

I have enough delta-v for a direct transfer to Kerbin

I use EVA construction to detach the empty tanks because decouplers have recoil

Eve and Kerbin gravity assists to slow down

Eve flyby

Propulsive capture

Aerobraking. Bill got toasty but didn't melt

Paragliding down

Safe and sound

 

[Turf]

Why is the sky in the last picture colored pink? Are you sure that's Kerbin you're landing?

Also, nice use of the cheap Baguette tanks and booster-only first stage. Great for when you're trying to conserve funds in Career mode.

You can just use an SSTO and land back on the runway in one piece for even cheaper option, but this one is impressive.

[camacju]

  On 6/21/2021 at 11:43 AM, Turf said:

Why is the sky in the last picture colored pink?

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I have a mod that puts a red target icon over your estimated landing position, and it shows up even if you're landed  (so in this case it is in the sky). If you look at the Kerbal Engineer heads-up display, you can see that the biome is "Water" which is Kerbin exclusive.

Also Bill's helmet cam shows a normal sky

  On 6/21/2021 at 11:43 AM, Turf said:

Are you sure that's Kerbin you're landing?

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Wouldn't that be embarrassing? I don't have any planet mods so the only other possibility would be Laythe. And I already visited there.

  On 6/21/2021 at 11:43 AM, Turf said:

You can just use an SSTO and land back on the runway in one piece for even cheaper option, but this one is impressive.

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If you don't have enough funds to build a SSTO in the first place that's not an option anymore (: Launch cost optimization is more fun than a SSTO as well.

And anyway, SSTO to Laythe and back isn't the most fuel efficient option - it's more efficient to have a SSTO deliver your spacecraft to Kerbin orbit and go from there.