jool hardworking contract

[antipro]

Hi, while I was intent in which "Kerbin World-First Record-Keeping Society" contract to choose, I came across this one:

The hard part I mean isn't of course do EVA near jool or enter jool atmosphere, but "Transfer any crew between vessels".
Cause this means that I have to launch 2 vessels, one immediately after the other and make a "rendez vous" early while I'm in jool SOI or late in a jool very high elliptic orbit.
Moreover the vessels or just one of them needs to be capable to enter the jool atmo without being destroyed, so I think one vessel needs also a shield.
So, beyond the complexity inherent in the vessels construction, I'm not sure about how easy it is to RV them in this specific situation.
The easiest way I've though is to use tylo gravity assist to put both the vessels into an almost similar jool low eccentric elliptic orbit, then RV and transfer, then enter jool atmo and finally escape SOI, but this way seems to be a bit inefficient in terms of fuel consuming.
In short: how would you approach this mission?

Edited April 13, 2020 by antipro

[jimmymcgoochie]

You might actually be able to do the transfer part of this mission with a single craft, as long as it has two separate parts that can carry crew. Transferring crew from one part to another might count, but it's probably worth trying that somewhere a bit closer than Jool first to find out if it works.

The next best thing to do is to launch two identical rockets with a single crew capsule - only one of them should have a Kerbal in it! - and a probe core, using NERV engines if possible for their high efficiency, then fire them both at Jool with trajectories that are as similar as possible. It might help to aim at a moon to get the inclination the same, and turning the thrust limit way down on the engines will help make precise adjustments as a few millimetres per second at Kerbin makes many kilometres of difference around Jool. Once they've both arrived at Jool, rendezvous as usual, then do an EVA transfer from the crewed pod to the other one. You could also dock the two pods together which would have the added benefit of being able to transfer all the fuel over to the newly crewed pod to try and get home again... Or wait for a larger crewed mission to get there later and rescue them.

As for entering the atmosphere- you just have to touch it, set your periapsis 1m below the top of Jool's atmosphere and dip your toe into it before pinging back out again. No need for heat shields or anything. Alternatively you could drop a probe into the atmosphere, gather as much science as possible and then frantically try and transmit it before you get crushed by the atmospheric pressure or drop below -250m and are swallowed up by the planet itself (-250m is as low as you can go on Jool, then it will instantly be destroyed). You'll need A LOT of ablator to survive entering Jool's atmosphere and you'll also need a lot of battery capacity as solar panels will either be destroyed by the air flow or will provide a trickle of power- they give less than 5% power at Jool compared to Kerbin- and RTGs don't produce power quickly, and you'll need the power to beam that science data out before Jool eats your probe.

[antipro]

1 hour ago, jimmymcgoochie said:

You might actually be able to do the transfer part of this mission with a single craft, as long as it has two separate parts that can carry crew. Transferring crew from one part to another might count,

This doesn't work, it always need 2 separate vessels launches.

 

1 hour ago, jimmymcgoochie said:

Once they've both arrived at Jool, rendezvous as usual,

This is the hard part, cause "as usual" I do RV when vessels are in 2, low and high circular orbits, ok elliptic too but I've never did it when approaching a planet from the interplanetary space and when both vessels are arriving at the same time.
 

 

1 hour ago, jimmymcgoochie said:

As for entering the atmosphere- you just have to touch it, set your periapsis 1m below the top of Jool's atmosphere and dip your toe into it before pinging back out again.

Ok but I would like to have the time to get all the possible science and also enter atmosphere with a bit of realism.

 

1 hour ago, jimmymcgoochie said:

Alternatively you could drop a probe into the atmosphere

Thanks, using a probe will count as mission completed, but first I wanna return all the science and secondarily I actually have only one RA-100 at 220000Km so no way to communicate with the probe at this distance, unless I throw another closer relay.

Edited April 13, 2020 by antipro

[AHHans]

3 hours ago, antipro said:

In short: how would you approach this mission?

How about launching two vessels, docking them together in Kerbin orbit, transfer to Jool, undock them again, transfer crew, transfer crew out of one of the vessels, and then dump the "empty" vessel into Jool's atmosphere and and return with the other.

[antipro]

oh! it's a nice idea. or better:
launch a main vessel and just a capsule,
docking them in kerbin orbit, transfer to jool,
transfer jeb from the capsule to the main vessel after EVA, undock the empty capsule,
enter atmosphere with main vessel just enough to get high eccentric orbit,
get science into atmo, in low space and in high space,
leave soi, go home.

thanks 

Edited April 13, 2020 by antipro

[AHHans]

1 hour ago, antipro said:

launch a main vessel and just a capsule,

Kind of what I meant. As long as you remember to make that in two separate launches, it should work.

[antipro]

Update: I've tested the jool atmosphere vessels insertion, it wasn't exactly a joke.
A little difference in periapsis altitude produces a big change in the result apophis.
Also do an EVA into jool atmo must be done very fast or jeb explodes almost immediately.
I use the capsule attached in front of the main vessel like a shield.

I attach the 2 vessels ss:

Edited April 14, 2020 by antipro

[antipro]

update2: mission accomplished

it wasn't so easy as I expected: after I got all science in high and low space I did the aerobraking maneuver getting the jool atmosphere science.
But to achieve the "enter atmo" contract I had to be in a jool orbit before enter, so I had to complete another turn around.
Then, still in orbit, I did the spacewalk and the transfer crew.

here some other ss: https://www.dropbox.com/sh/1t8hjs5ophdz4se/AADdh3MO6bbbXDG1PN3XkiOaa?dl=0

see ya

[AHHans]

1 hour ago, antipro said:

update2: mission accomplished

Congrats!