Help please

[Sof]

Long story short, my mission to Gilly ended in a horrible disaster. Part of the lander is still there, but the rest of it, including the crew, crash landed on Eve.

What kind of monstrosity is needed to land and take off from Eve?

[duncan1297]

You are going to need a pretty big ship. apparently a ship capable of lifting off and orbiting eve needs to be able to take off and land twice on kerbin.

[OrbitusII]

You could also develop a multi-man SSTO to take them off, but SSTOs are no small task. Still, I think developing an Eve-capable SSTO would be easier than developing a rocket that carries a rocket that can get into Eve orbit from its surface... Either way, it's going to be a big project.

[Sof]

I'm thinking assemmbly in orbit so the rocket from Kerbin doesn't have to be as big.

Would it be better to build one in Kerbin orbit then transfer to Eve, or use tugs to get each piece over to Eve orbit first?

[MrTaxman]

Perhaps you could trawl the forums to find some pre-made crafts that have been put together to save you some time and heartache (plus, it'll show you how they're put together).

[Clamps]

Make a rocket plane. Best way to get off of Eve.

[legodragonxp]

If at first you don't succeed, destroy all evidence that shows you tried. Nuke the entire site from orbit, it is the only way to be sure.

-Lego

[msyblade]

Think you may have just started your first "Eve colony"!

[capi3101]

Wow...

Okay, so getting down to Eve isn't hard; it's the "getting back up part" that's tough. I'd start by designing an automated payload: a probe core and two PB-NUKs, a hitchhiker, a big RCS tank, a docking port, some radial chutes and 8-12 RCS blocks. Say about seven or eight tonnes all told. That'll be what you return to orbit from Eve - have a tug standing by in orbit to rendezvous and haul that thing back to Kerbin.

Then the tricky bit is building a 12,000 m/s delta-V booster with that seven tonne payload. Gravity turn starts at 40,000.

I'm trying to apply Temstar's asparagus-stage rocket design equations to the problem...trouble is I don't know if they're Kerbin-specific or not.

[tomf]

Asparagus is the way to go, the principles are the same, you just need to use Eve's gravity for the TWR. To get two of the surface of Eve I used two 1 man capsules (lighter than 2 man capsules) on top of a 909, on a 45, on 4 clustered aeorspikes, surrounded by 6*4 aeorspike clusters, surrounded by 6 * mainsails for a total delta-v of 12000 and a mass to orbit ratio of about 4%

[capi3101]

I must be applying the equations wrong then...they're telling me my asparagus-staged 2.05 tonne payload rocket just needs to weigh maybe 16 tonnes to make orbit from the surface of Eve. That's why I'm thinking there must be some sort of adjustment for the different delta-V requirement.

I'm actually really growing to like the Mk1 Lander Can. As far as a "crew to mass" ratio goes, it's the best (0.6 tonnes per crewman, slightly better than a Hitchhiker). A payload of two Mk-1 Lander cans, a small RCS tank, eight RCS blocks, a senior docking port and two radial chutes comes in at 2.65 tonnes and could definitely get the job done as far as getting two guys off of Eve is concerned. You'd have to dump off the two Kerbals originally manning the cans; nothing an orbiting space station couldn't handle/fix. An OKTO2 probe core and a pair of PB-NUKs added to your payload would put you at just over three tonnes and let you keep control of the thing.

[John FX]

I must be applying the equations wrong then...they're telling me my asparagus-staged 2.05 tonne payload rocket just needs to weigh maybe 16 tonnes to make orbit from the surface of Eve. That's why I'm thinking there must be some sort of adjustment for the different delta-V requirement.

I'm actually really growing to like the Mk1 Lander Can. As far as a "crew to mass" ratio goes, it's the best (0.6 tonnes per crewman, slightly better than a Hitchhiker). A payload of two Mk-1 Lander cans, a small RCS tank, eight RCS blocks, a senior docking port and two radial chutes comes in at 2.65 tonnes and could definitely get the job done as far as getting two guys off of Eve is concerned. You'd have to dump off the two Kerbals originally manning the cans; nothing an orbiting space station couldn't handle/fix. An OKTO2 probe core and a pair of PB-NUKs added to your payload would put you at just over three tonnes and let you keep control of the thing.

Do your equations take air drag losses into account as that is what costs the most fuel losses launching from Eve?

Myself, I have grown attached to a turbojet first stage as it needs so much less mass to launch to orbit when there is an atmosphere (and therefore much less mass to get to Eve). With a TWR of 4 or more they get you to orbit quite nicely.

[HoY]

You obviously know there's no oxygen in Eve's atmosphere but not everyone else may know that.

Conventional jet engines and turbo jets won't work on eve. The Kethane jet engine Will however work. You could quite easily make a spaceplane using the Kethane mod to land and refuel itself then return to orbit.

For that matter, most people are presuming you want to stay completely stock. If you go non-stock there are several options available to get off of eve quite easily

[capi3101]

Do your equations take air drag losses into account as that is what costs the most fuel losses launching from Eve?

No. The first equation is payload fraction (15% of the rocket's mass is payload) leading to the target total rocket mass, the second calculates the total thrust for a 1.6 to 1.7 surface TWR, and the third calculates how much of the total thrust (22%) needs to be allocated to the central stack. That's how Temstar designed his Zenith booster family (which a lot of people are now utilizing, including myself). Now, those equations are for achieving Kerbin orbit with an asparagus-staged booster, so I assume some adjustment needs to be made to the payload fraction assumption for Eve. I just don't know what the adjustment is; I'm assuming I should be using an Eve payload fraction of 1.17% just based on the delta-V requirement difference.

You sure air drag loss accounts for most of the fuel expenditure from Eve? Best I can tell it's a little over 6,360 m/s to achieve a 107 km orbit and about 5,640 m/s to account for drag.

[John FX]

You obviously know there's no oxygen in Eve's atmosphere but not everyone else may know that.

Conventional jet engines and turbo jets won't work on eve. The Kethane jet engine Will however work. You could quite easily make a spaceplane using the Kethane mod to land and refuel itself then return to orbit.

For that matter, most people are presuming you want to stay completely stock. If you go non-stock there are several options available to get off of eve quite easily

DOH! completely forgot that. I was working on the assumption that jets would work in air (not remembering that `air` means something different on Eve)

[John FX]

No. The first equation is payload fraction (15% of the rocket's mass is payload) leading to the target total rocket mass, the second calculates the total thrust for a 1.6 to 1.7 surface TWR, and the third calculates how much of the total thrust (22%) needs to be allocated to the central stack. That's how Temstar designed his Zenith booster family (which a lot of people are now utilizing, including myself). Now, those equations are for achieving Kerbin orbit with an asparagus-staged booster, so I assume some adjustment needs to be made to the payload fraction assumption for Eve. I just don't know what the adjustment is; I'm assuming I should be using an Eve payload fraction of 1.17% just based on the delta-V requirement difference.

You sure air drag loss accounts for most of the fuel expenditure from Eve? Best I can tell it's a little over 6,360 m/s to achieve a 107 km orbit and about 5,640 m/s to account for drag.

Must again admit I was speaking from assumption rather than calculation, I just thought air drag might account for the difference between what you got and what you expected. Do you have a link to Temstar's asparagus-stage rocket design equations? I`d quite like to put some numbers in and see what comes out for my craft.

[Synapse]

I would go with the Nuke option

[chemieglennie]

You could take a long walk up a mountain. You can get away with about 8000 dv from the top of the highest mountains. About 6000m above sea level I think.

[Tiron]

You obviously know there's no oxygen in Eve's atmosphere but not everyone else may know that.

Conventional jet engines and turbo jets won't work on eve. The Kethane jet engine Will however work. You could quite easily make a spaceplane using the Kethane mod to land and refuel itself then return to orbit.

For that matter, most people are presuming you want to stay completely stock. If you go non-stock there are several options available to get off of eve quite easily

Hate the Zero Bypass Turbine so much. I cheated once several versions back to try it out on Kerbin...bloody aweful. I looked into the CFG to find out why, and well...

It uses Kintakeair instead of Intakeair, so normal intakes don't help it any. It ONLY uses the Intake integrated into the engine itself, and it's set up...really badly. It LOSES efficiency as speed increases, and it's set up so the primary driver of Kintakeair production is... throttle. So to get maximum kintakeair you have to max out the throttle, but that increases your speed, which cuts your kintakeair production.

Hopefully he's fixed this next bit, but...the biggest problem I had with it is that because of the link between Kintakeair and throttle, the thing would actually FLAME OUT if you cut the throttle too much. Including if you activated it on the runway with too low of a throttle setting. And since the kintakeair production is primarily linked to throttle rather than speed, it's EXTREMELY difficult to get it to restart if it flames out (Flameout = no throttle = very little kintakeair = flameout).

I'd want to test it again to see if he's fixed it (There have been a LOT of new Kethane releases and a KSP version or two since then), but if it was still like that...I'd probably just hack the normal intakes to also produce kintakeair.

[capi3101]

Must again admit I was speaking from assumption rather than calculation, I just thought air drag might account for the difference between what you got and what you expected. Do you have a link to Temstar's asparagus-stage rocket design equations? I`d quite like to put some numbers in and see what comes out for my craft.

http://forum.kerbalspaceprogram.com/showthread.php/28248-Is-asparagus-the-best-staging-system-%28might-contain-science%29?p=346702&viewfull=1#post346702

The correction I applied for an Eve payload fraction proved quite insufficient, though I wound up with a solid Tylo excursion module...