Getting an EVA repport while flying at Jool

[Tatonf]

Ok here's the challenge : getting an EVA repport while flying at Jool AND returning the kerbal back into Jool's orbit.

But that's quite hard, because it means going under 120 000m.

I tried aerobreaking but that's too hard, even from low Jool orbit your speed is still 5668 m/s, which leads to burning from 198 000m.

Because you need fuel and engines to make your ascent, your ship is heavy and therefore have more energy to lose, and the heatshield doesn't seem to handle it. I tried to stack several of them with decouplers, but as soon as I stage everything explodes (because of overheathing says the report).

What I could do instead is a power descent, but that would require around 3000 m/s of delta-V if I want to bring my speed to 2668 m/s, not acounting for the gain of speed because of gravity.

But that's still doable.

My main concern is how to get the Kerbal out to make the EVA report. If he have to support a too strong G-force he just fly off the ship. So it means I have to slow down my ship enough so the atmosphere doesn't slow my vessel, which basically means briging my speed near to 0m/s... And which means I need around 6000 m/s to go back into orbit !

If I could save some speed from my orbit that wouldn't be that hard, but I don't know how to do that.

The last problem is the ascent. You can't go above 2500/3000 m/s at best while inside Jool's atmosphere no matter what your altitude is, but you need to achieve 5668 m/s for orbiting Jool. So yes, you can just go straight up and make a radial burn while is space, but that's ineficient compared to a good gravity turn, meaning you need more delta-V...

The only good new is that Jool's atmosphere isn't that dense at 120 000m, atomic motors are still working with an ISP of 555s at this altitude (though it decrease quickly at this point, only 400s at 110 000m).

But using atomic motor is adding heat to an already existant heat problem...

[Glaran K'erman]

I will quote someone who wisely answered a question similar to this regarding another Jool contract. See that little red X in the upper right corner, that's how you complete this one.

[X-SR71]

What if you like put a command seat inside a cargo bay, get your kerbal seated there while still in orbit, and try to leave seat and scan in atmosphere while still inside the (closed) cargo bay? He's gonna bounce and kick a lot and his brain will probably turn to mush in there, but he would survive, right? Would that work?

[Tatonf]

I will quote someone who wisely answered a question similar to this regarding another Jool contract. See that little red X in the upper right corner' date=' that's how you complete this one.[/quote']

Hey. That was for planting a flag on Jool, which is indeed impossible. And while difficult, I don't think that my problem is impossible. Plus it's not even a contract, just a challenge.

What if you like put a command seat inside a cargo bay, get your kerbal seated there while still in orbit, and try to leave seat and scan in atmosphere while still inside the (closed) cargo bay? He's gonna bounce and kick a lot and his brain will probably turn to mush in there, but he would survive, right? Would that work?

Hmmm may be. But I must be able to right click on the kerbal. May be if I zoom in correctly...

[Glaran K'erman]

Ah ok not a contract, gotcha, well perhaps, and I still can't believe that contract was generated....

[ajburges]

Really, heating makes this truly impractical. Abort or hope version 1.1 tweaks the atmo to make this plausible. The delta-v requirements to come in at half-orbital speed, then cancel that speed to escape on a near radial orbit (if you can't build horizontal speed due to atmo, you need to GTFO of the atmo ASAP), and obtain elliptical orbit after escape is fearsome.

As for making the report once you are there: just use a cargo bay with a external seat. Open bay, get report, close bay.

I have not done this, but this would be my approach:

A Deorbit stage with enough dV to kill orbit (sounds like 3-4 km/s). Can recover this portion with maybe an additional initial dV of .5 km/s

A Mk3/3.25m "lander" stage with substantial wings to control descent.

An ascent stage(s) protected by a cargo bay. Enough dV and TWR to ascend to a radial suborbital trajectory (TWR of 2.2-2.4 and a dV of who knows).

An orbital stage atop the ascent stage with dV to take the suborbital trajectory orbital. The kerbal should sit in a bay that can be opened while docked to the lander (dV dependant on ascent stage).

A support vessel to top-off the tanks and retrieve the return vessel (reducing the mass requirements of the rest)

The lander wings allow you to translate a lot of that downwards velocity into horizontal velocity. This makes the ascent stages job a little easier.

The ascent stage needs to be streamlined enough to escape and enough TWR to beat terminal velocity. (unless thermal precludes terminal velocity)

The rest is orbital maneuvers.

[X-SR71]

And post screens if you actually manage it!

[Tatonf]

Well I've been avoiding everything related to planes since I started to play this game 2 years ago, so it's gonna be hard, but I'll give it a try. Thanks !

[GarrisonChisholm]

My main concern is how to get the Kerbal out to make the EVA report. If he have to support a too strong G-force he just fly off the ship. So it means I have to slow down my ship enough so the atmosphere doesn't slow my vessel, which basically means briging my speed near to 0m/s... And which means I need around 6000 m/s to go back into orbit !

If I could save some speed from my orbit that wouldn't be that hard, but I don't know how to do that.

What I have done is build a Structural Box Cage around the EVA port, since really the Kerbal should have a tether/umbilical I don't consider it outrageous. I've only used it in zero-g, but it should assist you in an atmosphere too.

[Tatonf]

Thanks for the advice, but ajbuges reminded me that you can make EVA report from the external seat, which is much more convenient.

[TotalNewb]

Airbrakes! They can slow you down incredibly quickly, maybe even without burning up in the process.

[Laie]

Thanks for the advice, but ajbuges reminded me that you can make EVA report from the external seat, which is much more convenient.

But it requires the Kerbal to sit outside for some time. IIRC Kerbals aren't very heat resistant and can go poof under Eve's midday sun.

The problem with leaving a pod is that the kerbal will be ripped from the ladder immediately. The solution is to orient the pod such that the kerbal will be pushed against the hatch. This worked well some versions ago when there was no heat. Now... I doubt that a Kerbal can survive in that place even for the few seconds it takes to gather an EVA report.

[2001kraft]

Apoapsis of 500k km, periapsis of 118k km. As soon as you enter atmosphere, get out, do the report, get back in. Done. Be super quick.

Edited July 25, 2015 by 2001kraft
Capitalization being a failure.