Deepest Safe altitude in the Joolian Atmosphere?

[Brainlord Mesomorph]

I want to send a manned probe into Jool's atmosphere to run some science and one quick door-clinging EVA. Then back in the ship, hit the rockets and get out!

Its a low-drag 2 stage assent non-lander. Total delta V 5000 m/s TWR: 2 (Kerbin)

I know there's a Kraken down there.

How deep do you think I can *safely* go?

[Othuyeg]

100m is where you hit the "surface"

You can actually land... sort of. Your ship will be destroyed.

[Brainlord Mesomorph]

100m is where you hit the "surface"

You can actually land... sort of. Your ship will be destroyed.

Hence my request for the lowest SAFE distance.

[Othuyeg]

Hence my request for the lowest SAFE distance.

101 meters

[FleshJeb]

I suggest trying that EVA on Kerbin first to find a safe altitude where the kerbal won't get torn off. Either get the air pressure at that altitude from a mod, or plug it into the atmo equation: http://wiki.kerbalspaceprogram.com/wiki/Kerbin#Atmosphere

Find the equivalent altitude on Jool (http://wiki.kerbalspaceprogram.com/wiki/Jool#Atmosphere).

Keep in mind you may be going faster when Jool-diving, so you may want to calc the drag on the Kerbal (http://wiki.kerbalspaceprogram.com/wiki/Atmosphere). Or just add a safety factor.

IIRC, the safe altitude for opening solar panels and stuff on Kerbin is 29k.

[MartGonzo]

If using Deadly Reentry you can aerobrake down to about 125 km, below that bits burn off

Edited December 4, 2014 by MartGonzo

[Empiro]

I'm still not too sure what you're attempting to accomplish -- if you're trying to get upper atmosphere data, then you'll want to be as high as possible while within the atmosphere (138km). Keep in mind that you need to be on a sub-orbital trajectory to count as flying, you'll basically want to aerobrake at high altitude (making multiple passes as required) until you're sub-orbital, take your readings, then get out as quickly as possible.

The craft as given is probably not going to be able to get "flying low" and still make it out. I'm not sure what altitude that is, but you'll probably need well over 15k m/s Delta-V to make it out from those altitudes.

[LordFerret]

I got down as far as 250m before I met the Kraken. That was in v0.23.5, I've not been back since.

[SRV Ron]

I got down as far as 250m before I met the Kraken. That was in v0.23.5, I've not been back since.

That is -250 meters. Note how slow the probe was going with parachutes not deployed. Note the pressure reading going down.

[Cerberus738]

I made it down to +400m before i exploded. The "surface" disappeared and turned into a black void around 5k if i remember correctly. As far as escaping the atmosphere... you better plan to go shallow. You could pack up a few probes with 5km/s dV and launch them ahead to see what depth they can escape from.

[Brainlord Mesomorph]

I made it down to +400m before i exploded. The "surface" disappeared and turned into a black void around 5k if i remember correctly. As far as escaping the atmosphere... you better plan to go shallow. You could pack up a few probes with 5km/s dV and launch them ahead to see what depth they can escape from.

That's a good idea.

off to the VAB to build some 5km/s probes!

Also: after sleeping on it: Shouldn't I just keep an eye on my orbital speed as I descend and the moment I loose 5000 m/s, THEN its time to start the engines, right?

Edited December 4, 2014 by Brainlord Mesomorph

[Laie]

I've tried a few times in 0.24 and always made it to "sea level". Ship kept descending, though, taking me below the "surface" (world turned black as I was looking at the planet from the inside), the vessel was destroyed when the altitude reached -150m.

If all you're really after is science, you can get "flying at" reports already at relatively high altitudes. I managed to get mine while aerobraking (130km or higher).

Leaving the pod is tricky while under acceleration (be it thrust or drag), chances are that your kerbals can't get hold of the ladder and will get lost. If they're already holding the ladder before things get rough, however, they will cling to it come hell and high water. So I recommend to take the kerbals out of the pod well ahead of time. Alternatively, you may use an external command seat to get EVA reports without fear of your Kerbal getting lost. And immediately transmit the report, too, as a Kerbal in a seat is considered to be part of the craft and has access to the comms device.

[cantab]

Not very. It takes something like 30 km/s to ascend from datum (0 m altitude).

[michaelsteele3]

101 meters

You took my smartalec phrase! Now I can't use D:

[LordFerret]

That is -250 meters. Note how slow the probe was going with parachutes not deployed. Note the pressure reading going down.

http://i.imgur.com/vozQ6EP.jpg

http://i.imgur.com/dyG6FOd.jpg

http://i.imgur.com/Xr1Vmz8.jpg

I didn't have chutes, just Ion and Mono. Once in the atmosphere, it really slowed itself down.

Just before entering the atmosphere...

Hitting atmosphere...

Just dropping, approx. 95m/s...

The Kraken reaching up to get me... slowing to just under 20m/s...

250m... BOOM! lol

[Engineer of Stuff]

You could land on it before .23. I have heard that there was even a separate science biome for it.

http://wiki.kerbalspaceprogram.com/wiki/Jool

[LABHOUSE]

I would not go deeper than 500 and you can get flying low science at 999 I. I would make an Eva "cage" if I were you.

Edited December 4, 2014 by LABHOUSE

[Kryxal]

MechJeb on hearing that Jeb wants to try this stunt:

"Just what do you think you're doing, Jeb?"

[Brainlord Mesomorph]

I had a lovely vision of a thing parachuting into the atmosphere of Jool, doing some science, and rocketing out. But no.

While I can design all kinds of things with all kinds of delta V, as I’m experimenting in Kerbin orbit, trying to get anything to go from orbit, to aerobreaking to suborbit, and then attempting to recover, start rocket engines, and head back to orbit… but no. It doesn’t work.

I’d figured you would lose a lot of velocity in aerobreaking, but I also figured your trajectory would still be basically horizontal, but it’s not, it’s basically straight down. And the whole situation is getting worse by the second. You can try to recover , but you would need a ludicrous TWR

Parachutes? Nope. Too late to help.

Maybe wings, I have been able to recover space planes to straight and level flight after reentering. But transatmospheric flight would require twice as much fuel. If you want to carry oxidizer more than twice that. And to carry all that fuel will you would need twice as much fuel.

I think this thing ends up being a Saturn V with wings. So … no.

Exploration of the atmosphere of Jool will have to be limited to one way probes.

(at least for now)