Mun Extreme EVA

[DrMonte]

For those who did not hear the term "extreme EVA" in KSP it stands for - visiting celestial body in swimsuit EVA. It is not possible to land and takeoff from the Mun in a single run so we will stay here only with one part of the journey - the harder one

The short story

Jeb finally landed on the Mun and he is very happy about it (just look at his face). Unfortunately landing was not very successful and all ship fell to pieces. Daily situation in KSP if you would ask me.

Good news - Bill is still orbiting the Mun in the return capsule.

- Can Jeb get to the orbit around the Mun using just his EVA Jetpack?

- Will Bill be able to catch Jeb in such low orbit?

Rules

The idea is to solve a question - Is it possible to get into Mun orbit using only EVA Jetpack? Of course Kerbal must live so someone must save him there and bring home.

1. I don't care how you bring poor Kerbal to the Mun. Challenge starts here.

2. On the Mun Kerbal can not get any help from any technology. Starts in a way how it stands - in EVA with JetPack.

3. Kerbal must board the ship orbiting the Mun.

4. The orbiting ship is allowed to change trajectory as you like except it should not perform landing maneuvers.

Forum rules says we have to have some ranking system:

1. Starting Kerbal altitude on the Mun - H. You get (8000 - H) / 100 points for reaching stable orbit. (The lower you start the higher is reward)

2. 20 points for boarding the ship.

3. 5 points for landing on Kerbin.

Don't forget to screenshoot.

Made it

Kasuha - 105

UrstMcRedhead ~ 69

DrMonte - 62

Edited April 28, 2014 by DrMonte

[skykooler]

The answer to your question is no, it is not possible to get into Mun orbit with only a jetpack; the Kerbal's jetpack has about 550 m/s of delta-v, while you need at least 600 to reach Munar orbit.

[The Error]

...unless you put him as close as possible and catch him with the orbiter.

Hmm....

[TMS]

You can rendezvous with a sub-orbital trajectory.

Tricky to get the timing right.

[DrMonte]

You know I've started this challenge 'cos I didn't found any similar in the forum. The question - "Is it possible to get into Mun orbit using only EVA Jetpack?" arose in the forum and there is no reason why you couldn't.

Kerbals Jetpack has ~550dV; To get to quite "high" ~14km orbit you need ~640dV. But Mun is airless body and its highest peak is 7061m somewhere in southern pole. So it's enough to get to ~7km orbit to not to hit a mountain. Also you might find a mountain for starting point to save some dV.

[BagelRabbit]

Scott Manley did a video on this where he used an upside-down lander's engine to mass-relay a Kerbal with enough delta-V to get him into orbit, where he rendezvoused and entered another capsule. I can't find the video though.

I don't know if this would count as 'lack of technology' but it's a place to start.

[WhiteKnuckle]

It is also possible to get a ship in an orbit that takes it under the height of surrounding terrain (the equatorial canyon) Not sure if the jetpack has enough DV to get anywhere near the kinds of speeds a ship would be traveling on an orbit that low, but if you could pull it off it'd look really really cool.

[DrMonte]

Ok, I'm teasing you, I've done it and don't find where to post it. It's quite fun and might be easier than you think.

The Eagle Jeb has landed. Altitude 4300m. Somewhere at equator.

One small push of RCS one big step for Kerbal kind or whatever. EVA does not have the Navball so let the stars show your path.

In the orbit. Pe:7865, Ap:13126.

Passing over the landing site. One full circle and still alive though!

What a hell is there? Nice view provides hope.

Here you are. Rendezvous at this altitude takes some nerves.

Grab. It's not seen in the picture but Jeb's spinning like hell and there's no RCS to stop him.

Going home.

[thereaverofdarkness]

Would be neat to flesh out this challenge with other bits of things Jeb is allowed to use to get a boost with, and see how high of an orbit people can reach, or challenge people to make landings as such. The EVA pack should be the main fuel source, but other minor boosts could be allowed, such as:

1.) mechanical catapults

2.) the still-running engine of Jeb's face-down rocket (just like in the menu screen)

3.) wheels - launch a rover over the top of a hill

4.) jump off a tower and bounce

5.) use a tower to get a higher starting point

6.) use the height from a tower, cliff, or crater edge to decrease the vertical thrust needed during launch

7.) clip launching: get Jeb stuck inside something such that he gets launched out of it.

8.) Buddy system: have Jeb hold hands with another Kerbal while he rides that Kerbal's EVA pack out of fuel, and then lifts off on his own with a full pack. Might require a mod to allow them to hold hands.

[generalguy26]

[deleted]

Edited March 21, 2023 by generalguy26

[DrMonte]

Maybe being on minmus would be easier.

There is a Minmus challenge somewhere here. Just that with Minmus it's a full EVA challenge - land, takeoff and board a ship.

[The Destroyer]

It's definitley possible on Minmus.

Also. If you have KAS, and say, your lander explodes on gilly except the command module, you could grab the parachute, escape gilly, go to Eve, and parachute down. Not that you would want to go there, it's hard!

[DrMonte]

Would be neat to flesh out this challenge with other bits of things Jeb is allowed to use to get a boost with, and see how high of an orbit people can reach, or challenge people to make landings as such. The EVA pack should be the main fuel source, but other minor boosts could be allowed, such as:

1.) mechanical catapults

2.) the still-running engine of Jeb's face-down rocket (just like in the menu screen)

3.) wheels - launch a rover over the top of a hill

4.) jump off a tower and bounce

5.) use a tower to get a higher starting point

6.) use the height from a tower, cliff, or crater edge to decrease the vertical thrust needed during launch

7.) clip launching: get Jeb stuck inside something such that he gets launched out of it.

8.) Buddy system: have Jeb hold hands with another Kerbal while he rides that Kerbal's EVA pack out of fuel, and then lifts off on his own with a full pack. Might require a mod to allow them to hold hands.

Mun EVA landing challenge would be easier. I remember that in 0.21 we've done this at one shot with >40% prop left no trying to optimize landing too much.

I'm quite interested in fact itself that "escape from the Mun can be done just by EVA". If you crash your ship there is no help here. The only thing you can do is just walk to the higher mountain to gain more launching altitude. Also there are challenges for the lightest craft to the Mun. Is there requirement to light an engine on liftoff?

[Kasuha]

It is possible from any altitude, you don't need to climb up a hill. Tried it from 0 altitude (would go even lower but these places are rather uncomfortable) and while my orbit wasn't that pretty it was possible to rescue Jeb in two orbits without problems. I'll upload screenshots in a while.

[DrMonte]

It is possible from any altitude, you don't need to climb up a hill. Tried it from 0 altitude (would go even lower but these places are rather uncomfortable) and while my orbit wasn't that pretty it was possible to rescue Jeb in two orbits without problems. I'll upload screenshots in a while.

I might even think that it is possible to land and takeoff but that would be a really daring challenge.

Jeb can survive ~100m/s impacts (depends on situation) and we have >7km mountain on the Mun. That leaves lots of variants to think of.

[Kasuha]

I might even think that it is possible to land and takeoff but that would be a really daring challenge.

Jeb can survive ~100m/s impacts (depends on situation) and we have >7km mountain on the Mun. That leaves lots of variants to think of.

I seriously doubt that. You don't need much more than orbital dv to get to orbit, but to brake from orbit you spend almost that much even if you don't have to brake to zero.

Anyway, pictures:

Javascript is disabled. View full album

[donfede]

...You don't need much more than orbital dv to get to orbit

Nice detailed pics, thx.

Is "orbital dv" listed anywhere? I believe for Kerbin it's 2300ms (from a reddit post), and for the Mun it's ~600ms (from personal 'recollection/experience'). But I don't see these figures in the wiki pages (ex: Kerbin, Mun). Am I missing them, or are they listed elsewhere?

[Nao]

I seriously doubt that. You don't need much more than orbital dv to get to orbit, but to brake from orbit you spend almost that much even if you don't have to brake to zero.

Anyway, pictures:

[snip]

Nice job, but there is even better way to get to orbit from Mun surface. Use mouse to rotate the kerbal just like you would with rocket, and only thrust in one direction staying as low as possible. Thrusting up and froward at the same time generates only 1,47 of unit of thrust in one direction while consuming 2 units of fuel, and due to Oberth effect it's better to accelerate as low as possible.

I didn't tried it much on current patch but 25km orbit should be pretty easy to achieve (starting from standard ~5km altitude).

I do agree that land and ascent again is out of the question without some kraken / landing on head shenanigans

[skykooler]

Nice detailed pics, thx.

Is "orbital dv" listed anywhere? I believe for Kerbin it's 2300ms (from a reddit post), and for the Mun it's ~600ms (from personal 'recollection/experience'). But I don't see these figures in the wiki pages (ex: Kerbin, Mun). Am I missing them, or are they listed elsewhere?

Low Kerbin orbit is about 2240 m/s - I remember this from back when I was learning the equations for orbital motion, and used the Kerbin system to test my numbers.

[UrstMcRedhead]

Ok so it only took two quickloads but I did it. I also had a few hiccups. The lander couldn't generate power, and TACLife really wanted to kill Jeb.

Every part of this mission was stock except for FAR, TacLife, Deadly Reentry, and ProcFairings.

Javascript is disabled. View full album

[donfede]

Low Kerbin orbit is about 2240 m/s - I remember this from back when I was learning the equations for orbital motion, and used the Kerbin system to test my numbers.

Nice tease kooler ... would you kindly share those equations so myself and others can use them on bodies beyond Kerbin?

[skykooler]

Nice tease kooler ... would you kindly share those equations so myself and others can use them on bodies beyond Kerbin?

The one in question is:

v = sqrt(GM/r)

where G is the gravitational constant, M is the mass of the planet you're orbiting, and v is your velocity at altitude r from the planet's center. Note that the last bit means that for Kerbin for example you need to add 600 to your altitude, because that's Kerbin's radius, so a 80-km orbit is really 680km radius.

For example, let's find the orbital velocity in low Mun orbit, at say 30 km. The radius is 200 km, so our r is 230,000. G is a constant and is about 6.67×10^{−11} N², and the mass of the Mun is about 9.76×10²⁰ kg. Plugging those in, we have

v = sqrt((6.67×10^-11) × (9.76×10²⁰)) / 230,000)

which works out to:

v = sqrt(283,040)

or:

v ≈ 532 m/s

[DrMonte]

Ok so it only took two quickloads but I did it. I also had a few hiccups. The lander couldn't generate power, and TACLife really wanted to kill Jeb.

Every part of this mission was stock except for FAR, TacLife, Deadly Reentry, and ProcFairings.

From images I can't see the starting altitude. I can take somewhat ~3600km for the results.

[SpenSpaceCorp]

Also. If you have KAS, and say, your lander explodes on gilly except the command module, you could grab the parachute, escape gilly, go to Eve, and parachute down. Not that you would want to go there, it's hard!

If I'm not mistaken, I do believe it is possible to EVA from the surface of Gilly all the way back to Kerbin (escaping Gilly's orbit at the right angle at the right time to escape Eve with less DV, provided the planets are lined up.

[kStrout]

I believe that Minmus's gravity is so light you can launch and return to Kerbin with an EVA pack.