Jool Return Challenge

[SingABrightSong]

The goal of this challenge is to return a vessel, intact, from Jool's lower atmosphere.

 

Rules:

• The vessel must return to Kerbin, due to the nature of the challenge and for the mission summary on Kerbin recovery, which will be used in scoring.
• The vessel need not return under its own power. A separate vessel may rendezvous with and redirect the vessel after it has exited Jool's atmosphere.
• No mods that alter atmosphere are permitted, for obvious reasons. A separate scoreboard may be created for FAR/DRE users, if any decide to take the challenge.
• Stock parts only. Certain modded parts(i.e. nuclear turbojets, propellers) allow aerodynamic flight without the consumption of fuel. As such, to present a level playing field, only stock parts are permitted.
• Visual mods, informational mods, QoL mods, and autopilot mods are permitted.

Scoring:

• .05 points for per meter below the atmospheric border at the craft's lowest point. Jool's atmosphere begins at 200 kilometers, so a craft with a periapsis of 100 km would score 5000 points in this regard.
• One point per science point recovered(not transmitted) from Jool's atmosphere(both upper and lower).
• Do note that, while the goal of the challenge is to recover a vessel from Jool's lower atmosphere, entrants will still be scored even if they only reach the upper atmosphere.
• BONUS POINTS: 2000 bonus points for recovering an EVA report from Jool's lower atmosphere. 10000 bonus points for recovering an asteroid sample from the lower atmosphere

My attempt is detailed in an Imgur album, which unfortunately cannot be embedded.

 

Leaderboard:

1. ManEatingApe:11489.45 points

 

 

Edited November 5, 2016 by SingABrightSong
Added leaderboard.

[ManEatingApe]

This was an interesting and tricky challenge. 

Initially I tried a craft resembling essentially a large dart with a high ballistic coefficient. The plan was to zoom through Jool's atmosphere without stopping, snatching some science along the way. Heat issues prevented this from working so instead I used a stretched version of an Eve lander design.

Jeb bravely descended to 48,611 metres and even managed 2 EVAs (a cunningly placed girder stopped him being swept away). Descending deep into the depths of a gas giant couldn't help but remind me of this entertaining novel

Here are some highlights:

The lowest point

Aerobraking got a little exciting

Jeb on EVA

Docking with the rescue tug

Safely splashed down on Kerbin

1920 science returned

Full mission album here

On a normal difficulty setting 1920 science was returned to Kerbin. (2 each of Crew report, EVA report, Thermometer, Barometer, Mystery Goo, Materials Lab and Atmospheric Analysis)

 

 

Edited November 4, 2016 by ManEatingApe

[SingABrightSong]

An impressive first entry! Your point total is 11489.45 points. As you are the first entry, you are the de facto leader.

[goduranus]

I've been wanting to do this challenge for a while, and made this stock "electric helicopter", which can lift 10-tons of payload from Jool's zero altitude right up ~125km(Tested it on Kerbin, it works up to 10km where pressure is ~15kpa, which corresponds to ~125km altitude on Jool). At this altitude all rockets will work pretty efficiently.

What's the minimum wet mass a rocket needs to be do reach Low Jool orbit from that altitude? I've tried a few designs with 6-7km/s deltaV but they are too heavy for this thing to lift.

[ManEatingApe]

15 hours ago, goduranus said:

What's the minimum wet mass a rocket needs to be do reach Low Jool orbit from that altitude?

@goduranus That's tough to answer as it will depend completely on your design (chemical/nuke, dry/wet ratio)

To give you an indication, the final stage I used weighed just under 11 tons and had a vacuum dV of 6,200 m/s

However it was already travelling upwards at 1500 m/s at the time I staged the nuke - as its TWR was relatively low this gave the nuke plenty of time to circularise. Even then it was pretty touch and go.

15 hours ago, goduranus said:

I've tried a few designs with 6-7km/s deltaV but they are too heavy for this thing to lift.

dV is much better indicator.  With a stock propeller design you'll be travelling upwards quite slowly (about 25-50 m/s) by the time you reach 125km altitude. You'll need substantially more than 6km/s dV to gain height and also a higher TWR than a pure nuke design.

I'd budget another 1500 to 2000 m/s at least. With a command pod 10 tons feels like it won't be enough, you could either scale up your design or check with @SingABrightSong to see if command chair entries are acceptable