Stranded

[Finchy_McFinch]

I recently got to Duna for the first time, but now my poor Kerbal is stranded there with not enough Delta V to get home. Does anybody have a rescue ship capable of carrying one Kerbal to Duna and two Kerbals home that I could use? Also, could somebody please teach me how to do a rescue mission?

Edited December 13, 2018 by Finchy_McFinch

[Gargamel]

Doing a rescue mission is easy.  Just launch a craft with sufficient dV to get there and back again, meet up with the stranded kerbal, and bring him home.    Since you've landed (I assume), you can launch back into to orbit, and meet up with your rescue craft.   This both simplifies the rescue mission, and reduces it's dV budget considerably. 

If you can build a craft to get to Duna and land, then you are easily quite capable of building one to perform the rescue operations.  Take a look through the various forums and threads for ideas.  But using somebody else's design, in a game where designing and building the craft is at least half the fun, you'd be doing a disservice to yourself. 

[Finchy_McFinch]

4 hours ago, Gargamel said:

Doing a rescue mission is easy.  Just launch a craft with sufficient dV to get there and back again, meet up with the stranded kerbal, and bring him home.    Since you've landed (I assume), you can launch back into to orbit, and meet up with your rescue craft.   This both simplifies the rescue mission, and reduces it's dV budget considerably. 

If you can build a craft to get to Duna and land, then you are easily quite capable of building one to perform the rescue operations.  Take a look through the various forums and threads for ideas.  But using somebody else's design, in a game where designing and building the craft is at least half the fun, you'd be doing a disservice to yourself. 

The thing is, I don't even have enough Delta V to get into Duna orbit! Also, I have no idea how to make Duna capable spacecraft that don't wobble everywhere.

[Foxster]

Is your tech tree complete? If not then post a picture of it. 

[bewing]

8 hours ago, Finchy_McFinch said:

The thing is, I don't even have enough Delta V to get into Duna orbit!

Get your rescue ship to high Duna orbit first.

Get your doomed ship as close to orbit as you can over Duna, have the pilot go EVA, have the pilot grab all the science data from the pod, let go of the ladder, turn on your RCS jetpack, face prograde, and burn like hell until the pilot has circularized himself. Then have your rescue ship rendezvous with him. He has almost 600 deltaV in his RCS jetpack -- and this is one of those times when you really need to use it.

If your spacecraft is "wobbling" then you probably need to turn on autostruts via Advanced Tweakables. Either that, or you built it non-symmetrically.

 

 

[dire]

9 hours ago, bewing said:

Get your rescue ship to high Duna orbit first.

Get your doomed ship as close to orbit as you can over Duna, have the pilot go EVA, have the pilot grab all the science data from the pod, let go of the ladder, turn on your RCS jetpack, face prograde, and burn like hell until the pilot has circularized himself. Then have your rescue ship rendezvous with him. He has almost 600 deltaV in his RCS jetpack -- and this is one of those times when you really need to use it.

If your spacecraft is "wobbling" then you probably need to turn on autostruts via Advanced Tweakables. Either that, or you built it non-symmetrically.

 

 

Caveat: It takes about 1500-ish delta-V to reach Duna orbit. If your craft has less than 1000 delta-V this will result in your poor kerbal failing to circularize and falling dramatically to his fiery death. You will want to reserve about 20% of the jetpack for the actual docking maneuver. You might not need 100 dV to figure out how to reach the airlock, but that will give you a good reserve, and if you aren't experienced with EVA's you may need all of that.

Do you have any mods installed? I recommend at least Kerbal Engineer Redux which will give you a number for how much dV you have on craft that have its widget. Not helpful for the stranded pilot but very useful for the rescue craft.

@Finchy_McFinch Threw this together for you https://kerbalx.com/direstorm/Duna-Express 

Engineering your own craft is half the fun, but if you don't know what your delta-V is, trying to guess your way off Duna can be a bit frustrating. Pro tip: Don't decouple your lander's fuel tanks until they are out of fuel

I can also recommend one of Matt Lowne's Duna rescues: 

 

Edited December 13, 2018 by dire

[Snark]

23 hours ago, Finchy_McFinch said:

I recently got to Duna for the first time, but now my poor Kerbal is stranded there with not enough Delta V to get home. Does anybody have a rescue ship capable of carrying one Kerbal to Duna and two Kerbals home that I could use?

How much dV does your stranded ship have?  You mention that it doesn't have enough to get to orbit, but how far short of that is it?

It takes about 1450 m/s to get to low Duna orbit from the surface.  Kerbal EVA packs have around 600 m/s of dV in them.  So, if your Duna lander has over 850 m/s of dV in it, then you can get your kerbal to Duna orbit, like this:

9 hours ago, bewing said:

Get your doomed ship as close to orbit as you can over Duna, have the pilot go EVA, have the pilot grab all the science data from the pod, let go of the ladder, turn on your RCS jetpack, face prograde, and burn like hell until the pilot has circularized himself. Then have your rescue ship rendezvous with him. He has almost 600 deltaV in his RCS jetpack -- and this is one of those times when you really need to use it.

...on the other hand, if your ship has less than 850 m/s of dV, then no, that's not going to work and you'll need your rescue ship to go all the way down to the surface (and land reasonably close to the existing ship), which would make the mission quite a bit more challenging.

1 hour ago, dire said:

this will result in your poor kerbal failing to circularize and falling dramatically to his fiery death.

Well, no-- a kerbal's not going to reentry-overheat on Duna.  But certainly the kerbal won't end up in orbit.  A kerbal that tries to reach Duna orbit and doesn't quite make it will either land safely with EVA parachute... or (if the kerbal doesn't have a parachute available) fall to the ground and go splat.

23 hours ago, Finchy_McFinch said:

Also, could somebody please teach me how to do a rescue mission?

Completely depends whether you can get your stranded kerbal to Duna orbit or not.

• If you can, then your rescue ship only has to get to Duna orbit, which is pretty easy.
• If you can't, then your rescue ship is going to have to do a fairly precise landing near your stranded kerbal, and then get back to orbit and all the way back to Kerbin, which is more challenging.

Either way is doable, but the "how to do it" instructions would be quite different in the two cases, so we need to know.

So... how much dV does your stranded ship have?

[Finchy_McFinch]

1 hour ago, Snark said:

How much dV does your stranded ship have?  You mention that it doesn't have enough to get to orbit, but how far short of that is it?

It takes about 1450 m/s to get to low Duna orbit from the surface.  Kerbal EVA packs have around 600 m/s of dV in them.  So, if your Duna lander has over 850 m/s of dV in it, then you can get your kerbal to Duna orbit, like this:

...on the other hand, if your ship has less than 850 m/s of dV, then no, that's not going to work and you'll need your rescue ship to go all the way down to the surface (and land reasonably close to the existing ship), which would make the mission quite a bit more challenging.

Well, no-- a kerbal's not going to reentry-overheat on Duna.  But certainly the kerbal won't end up in orbit.  A kerbal that tries to reach Duna orbit and doesn't quite make it will either land safely with EVA parachute... or (if the kerbal doesn't have a parachute available) fall to the ground and go splat.

Completely depends whether you can get your stranded kerbal to Duna orbit or not.

• If you can, then your rescue ship only has to get to Duna orbit, which is pretty easy.
• If you can't, then your rescue ship is going to have to do a fairly precise landing near your stranded kerbal, and then get back to orbit and all the way back to Kerbin, which is more challenging.

Either way is doable, but the "how to do it" instructions would be quite different in the two cases, so we need to know.

So... how much dV does your stranded ship have?

1496 m/s of Delta V. For some reason though, I don't even have enough for a 50 km orbit, which is the lowest I can do without being in the atmosphere.

 

Edit: Turns out I was wrong. I had JUST enough dV to get into orbit, and now I'm actually out of fuel and I just ditched my lander segment, leaving only the command pod and parachute. Sorry for the wrong information, for some reason Manouevre Nodes think you have a different amount of dV when you are in the atmosphere than in space.

Edited December 14, 2018 by Finchy_McFinch

[Finchy_McFinch]

17 hours ago, Foxster said:

Is your tech tree complete? If not then post a picture of it. 

I'm actually using sandbox mode.

3 hours ago, dire said:

Caveat: It takes about 1500-ish delta-V to reach Duna orbit. If your craft has less than 1000 delta-V this will result in your poor kerbal failing to circularize and falling dramatically to his fiery death. You will want to reserve about 20% of the jetpack for the actual docking maneuver. You might not need 100 dV to figure out how to reach the airlock, but that will give you a good reserve, and if you aren't experienced with EVA's you may need all of that.

Do you have any mods installed? I recommend at least Kerbal Engineer Redux which will give you a number for how much dV you have on craft that have its widget. Not helpful for the stranded pilot but very useful for the rescue craft.

@Finchy_McFinch Threw this together for you https://kerbalx.com/direstorm/Duna-Express 

Engineering your own craft is half the fun, but if you don't know what your delta-V is, trying to guess your way off Duna can be a bit frustrating. Pro tip: Don't decouple your lander's fuel tanks until they are out of fuel

I can also recommend one of Matt Lowne's Duna rescues: 

 

I have Kerbal Engineer Redux 1.3 (I prefer it to 1.5), Transfer window planner, Kerbal Alarm Clock and Trajectories installed. I am using KSP version 1.5.1. Also, thank you for the Duna Express ship! It will really help.

Edited December 14, 2018 by Finchy_McFinch

[Snark]

37 minutes ago, Finchy_McFinch said:

Edit: Turns out I was wrong. I had JUST enough dV to get into orbit, and now I'm actually out of fuel and I just ditched my lander segment, leaving only the command pod and parachute. Sorry for the wrong information, for some reason Manouevre Nodes think you have a different amount of dV when you are in the atmosphere than in space.

Woot!  Excellent. 

The fact that you're now in Duna orbit makes the rescue job a lot easier.

So, a couple of options.

One option would be to send an uncrewed rescue ship that's got some extra fuel and has a Klaw on it.  (Or just a docking port, if your stranded vessel has a docking port... but I'm guessing it doesn't?)  Send the rescue ship to Duna, do an orbital rendezvous with the stranded ship, latch on to it, and transfer fuel across to fill up the stranded ship's tanks.  Then let go and the no-longer-stranded-because-it-has-fuel-now ship can just send itself back to Kerbin, leaving the rescue ship at Duna.

The other option is to just send a rescue ship that has one open crew seat, and enough dV to go to Duna orbit and back again.  Rescue ship goes to Duna, then rendezvous with the stranded ship, then the kerbal in the stranded ship EVAs across to the rescue ship.  Then the rescue ship flies home.

Either way would work, they each have their advantages/disadvantages.

[dire]

1 hour ago, Finchy_McFinch said:

1496 m/s of Delta V. For some reason though, I don't even have enough for a 50 km orbit, which is the lowest I can do without being in the atmosphere.

 

Edit: Turns out I was wrong. I had JUST enough dV to get into orbit, and now I'm actually out of fuel and I just ditched my lander segment, leaving only the command pod and parachute. Sorry for the wrong information, for some reason Manouevre Nodes think you have a different amount of dV when you are in the atmosphere than in space.

Hey, grats on getting into orbit! The reason you have less delta-V when you are in an atmosphere is because your engines are actually less efficient in an atmosphere! Their specific impulse (Isp) is lower because the air pressure makes it harder for exhaust to leave your rocket. 

An option Snark has not mentioned, probably because it is more painful than leaving your astronaut stranded in space for a year or two: Align your craft to a kerbin return node, then have your astronaut get out and push the capsule prograde until he's spent 80% of his jetpack fuel. Pop him back into the capsule for a fresh tank, then rinse and repeat. Be careful not to send your capsule spinning!

Edited December 14, 2018 by dire

[Finchy_McFinch]

22 hours ago, dire said:

Hey, grats on getting into orbit! The reason you have less delta-V when you are in an atmosphere is because your engines are actually less efficient in an atmosphere! Their specific impulse (Isp) is lower because the air pressure makes it harder for exhaust to leave your rocket. 

An option Snark has not mentioned, probably because it is more painful than leaving your astronaut stranded in space for a year or two: Align your craft to a kerbin return node, then have your astronaut get out and push the capsule prograde until he's spent 80% of his jetpack fuel. Pop him back into the capsule for a fresh tank, then rinse and repeat. Be careful not to send your capsule spinning!

Ok, I will think about it.

Also, what is number is 80% of the pack fuel?

Edited December 15, 2018 by Finchy_McFinch
I had another question

[dire]

3 minutes ago, Finchy_McFinch said:

Ok, I will think about it.

Also, what is number is 80% of the pack fuel?

If you look at your ship resources while you are flying an astronaut, you can see they have 5 EVA fuel. 80% of that is 4 fuel and 20% is 1 fuel.

[Finchy_McFinch]

1 hour ago, dire said:

If you look at your ship resources while you are flying an astronaut, you can see they have 5 EVA fuel. 80% of that is 4 fuel and 20% is 1 fuel.

Thank you!

 

EDIT: I really hate to be the bearer of bad news, but I couldn't quite fly your Duna Express ship to Duna and back with an extra crew member. It isn't anything worng with your ship, I'm just a really inefficient KSP player and I also don't know how to do rendezouz in orbit. Sorry.

Edited December 15, 2018 by Finchy_McFinch

[Duck McFuddle]

Rescue missions are actually pretty easy, but there are a few things to keep in mind. One thing that some people (Like me ) forget is to have EXTRA SEATS for the stranded Kerbals. Another thing is that it is easier to land in a specific location if you have a polar orbit because then your ship will be orbiting vertically and the planet (With stranded Kerbal) will orbit horizontally. This makes it easy to wait for the two ships to be over/under each other. Then just send down the lander however you want (Apollo style or Direct Ascent style) and pick up your waiting passengers. Then hightail it back to Kerbin and give those guys a much-deserved rest after a few weeks on Duna. BUT!!!!! In your case, the ship is already in orbit so you need less DV to pick it up. It's pretty hard (At first) to rendezvous with a ship, so go find a good tutorial on docking. You could even try docking in Minmus orbit because of the lower gravity (Like in Matt Lowne's tutorial) and then go to Duna for the actual rescue. Good luck with the rescue!

EDIT: Just remembered one more thing... Kerbals themselves have a lot of DV in their RCS packs, so you can actually go pretty far without a ship. IF worst comes to worst, just use the RCS to get to Kerbin orbit and then do a rendezvous. 

EDIT 2: Well, just realized Snark said almost the exact same thing, so...

Edited December 15, 2018 by Duck McFuddle

[Draalo]

There are plenty of tutorial videos, just search youtube "orbital rendevouz ksp"

If you are playing career just accept a "rescue XY from orbit of Kerbin"-contract. Watch some vids, do the contract and get some practice. Maybe rescue one or two more with more contracts. 

Then all you need is a vessel capable of reaching Dunaorbit and have spare dV for the rendevouz, and of course the dV needed to get back to Kerbin.

(you can buy new Kerbals at the astronaut complex OR you can do rescue contracts, you ll get founds instead of paying. The rescued Kerbal will stay in your team for free  )

[magnemoe]

On 12/13/2018 at 6:03 AM, Finchy_McFinch said:

The thing is, I don't even have enough Delta V to get into Duna orbit! Also, I have no idea how to make Duna capable spacecraft that don't wobble everywhere.

You will need an fast rover, its hard to land accurate on Duna and you don't want to walk an kerbal 10 km
Make it an plate with four wheels and two seats, static solar panels for power, two small reaction wheels so you can rotate it if it flips. 
Set parachutes to open at maximum attitude and minimum air pressure. 
Main issue is that you have to wait for the next duna window. 

Going to duna is not much harder than going to the Mun, 500-1000 m/s more without optimizing. Gravity is higher so you want an stronger engine. Main issue is the transfer window and braking at the end. 

[Finchy_McFinch]

2 hours ago, magnemoe said:

You will need an fast rover, its hard to land accurate on Duna and you don't want to walk an kerbal 10 km
Make it an plate with four wheels and two seats, static solar panels for power, two small reaction wheels so you can rotate it if it flips. 
Set parachutes to open at maximum attitude and minimum air pressure. 
Main issue is that you have to wait for the next duna window. 

Going to duna is not much harder than going to the Mun, 500-1000 m/s more without optimizing. Gravity is higher so you want an stronger engine. Main issue is the transfer window and braking at the end. 

I actually just got into Duna Orbit. Maneuvre Nodes and ISP stuff, it confused me. Now I'm ACTUALLY stuck.

Edited December 16, 2018 by Finchy_McFinch

[magnemoe]

5 hours ago, Finchy_McFinch said:

I actually just got into Duna Orbit. Maneuvre Nodes and ISP stuff, it confused me. Now I'm ACTUALLY stuck.

Nice that saves a lot on the rescue as you don't have to land 
Some other are better in describing how to get to Duna and back. 

[Gargamel]

22 hours ago, Finchy_McFinch said:

Maneuvre Nodes and ISP stuff, it confused me.

Well, watch a lot of the tutorial videos out there.  Even the older stuff from really outdated versions are still applicable today.  The theory is the same. 

In addition, and some people will string me up for this suggestion, is I would install the MechJeb mod.  Use it to maneuver your craft where you need, but more importantly, use it like an experienced pilot teaching you how certain things are done.  Use it to set nodes, delete them, and then manually set them.  Be able to understand what you are doing, and why. 

[dire]

On 12/14/2018 at 5:08 PM, Finchy_McFinch said:

Thank you!

 

EDIT: I really hate to be the bearer of bad news, but I couldn't quite fly your Duna Express ship to Duna and back with an extra crew member. It isn't anything worng with your ship, I'm just a really inefficient KSP player and I also don't know how to do rendezouz in orbit. Sorry.

Did you try to do the rendezvous with the big ship, or with the little ship in its cargo bay? It's an apollo-style craft: the big ship picks an orbit and parks it, and then the little craft goes off and does stuff. I can believe you lost 4000 dV trying to rescue an astronaut in space, because I did something similar once, but you probably don't even need 400 dV in the little craft to complete your mission. The big ship only has about 6000 dV total, including launch to LKO, which is "enough" if you are reasonably efficient, but not a ton of margin for error. Hence the little ship.

The nominal delta-V for the rescue should be something like this: 3400-3500 dV to orbit, 1000 dV to Duna, 500 dV to circularize with aerobraking around Duna, 500 dV to return to Kerbin, and then a margin of 500 dV to play around with. And then the lander has 4000 delta-V, which is about 900 to land, 1500 to take off and 1600 to do docking and maneuvers. And you don't need to land or take off with it.

You can control the lander remotely by opening the big direct link antenna in the big ship's cargo bay, then activating the two relay antennas on the sides of the craft to establish a comlink to Kerbin. It needs to stay in line of sight, but that isn't usually a problem for landing, I've found; it's more an issue for taking off but on takeoff you'll be piloted xD

Sometimes KER lies to me about the delta-V though, and I only tested takeoff and landing with the craft, so I should probably check that it actually can get to Duna and back. I'm not playing stock right now and sending a Kerbal to Duna would be problematic for me in my current save with a stock craft because they would eat all their Snacks and then starve to death. Which would not make a good rescue.

Edited December 22, 2018 by dire

[Orion 1]

On 12/15/2018 at 8:31 PM, Finchy_McFinch said:

I actually just got into Duna Orbit. Maneuvre Nodes and ISP stuff, it confused me. Now I'm ACTUALLY stuck.

You still stuck? Because I could help...

IF YOU NEED IT

WINK, WINK.

ALL YA NEED TO DO IS ASK.

[Finchy_McFinch]

On 5/5/2019 at 2:50 AM, Orion 1 said:

You still stuck? Because I could help...

IF YOU NEED IT

WINK, WINK.

ALL YA NEED TO DO IS ASK.

[insert asking for help noises]

YES PLEASE OH MY GOD YESSSSSSS

ALL HAIL THE NEW MATT LOWNE!!!