• 0
Cannon

2.5m eve lander

Question

So basically I'm trying to land 3 kerbals on eve and get them back, while using tac life support.
This is what I came up with at first
ErPFJmN.jpg
Obviously it didn't work so I added 2 more side boosters so I had 6 instead of 4 (btw it's asparagus staging).
With 6 of them, I could get out of the atmosphere briefly, but not enough fuel was left in the last stage to get into orbit. Then I tried adding 1 small 2.5m fuel tank and poddle as my last stage, after the mainsails have gone, and it performed worse actually, twr was just too bad. I could try doing it with 8 boosters instead of 6 but that would be really heavy to get to eve + kerbals wouldn't have enough space to move around on eva since engines and tanks would be blocking their way on all sides.
I only need to get it to orbit with just a bit of fuel left so I can rendezvous with return ship and go home.
Does anyone have some advice for this?
Thanks in advance!

EDIT: I just figured I could leave all the life support stuff in the orbit since kerbals won't spend too much time on surface. Will try it out tomorrow and let you know how it goes.

Edited by Cannon

Share this post


Link to post
Share on other sites

10 answers to this question

Recommended Posts

  • 1

You have a few common Eve craft design problems going on there.

The answer to a failing Eve craft is almost never to add stuff - it's about taking stuff away. That and reducing drag - that's more important than messing with almost anything else. 

You can greatly reduce the accomodation mass by using a mk1 capsule and a mk1 crew cabin instead of the mk1-3. 

Get rid of the RCS completely - total waste of payload.

Dump all the 'chutes, airbrakes and anything else to do with landing before leaving Eve.

You seem to have a probe core in there half way up. What's that for?

Get rid of the struts (very draggy and heavy) and use auto-struts. 

Go mk1 all the way to reduce drag. 

What's in the service bay? 

Dump the solar panels and anything else bolted to the outside of the craft. 

 TT-70 Radial Decouplers are very draggy. Use hardpoints instead. 

Make sure the stacks are pointy. 

Vector engines are the best lower stage engines on Eve. A Terrier for the upper stage is good. 

What are those black and white striped things below the RCS tank?

Once the mass (and drag) are reduced a lot you won't need the RCS and additional reaction wheels but you will need some kind of fins at the bottom. 

By having a heatshield in there I'm guessing you plan to bring the lander back to Kerbin. If so, don't. Do it Apollo style. Just get your three crew down to Eve and back to Eve orbit, nothing else at all. Have the mothership do the rendezvous. 

Edited by Foxster
  • Like 2

Share this post


Link to post
Share on other sites
  • 1
3 hours ago, Cannon said:

I only need to get it to orbit with just a bit of fuel left so I can rendezvous with return ship and go home.
Does anyone have some advice for this?

You say you want to meet a return ship on low Eve orbit... try to shift functionality from the Eve lifter to the return vessel in order to reduce the mass of your payload. RCS fuel & thrusters is an obvious candidate, but also: is it really necessary to land the heat shield on Eve and carry it back to orbit? And four parachutes, a large reaction wheel, and so on?

3 hours ago, Cannon said:

EDIT: I just figured I could leave all the life support stuff in the orbit since kerbals won't spend too much time on surface. Will try it out tomorrow and let you know how it goes.

Yup, that would have been my next suggestion.

3 hours ago, Cannon said:

Then I tried adding 1 small 2.5m fuel tank and poddle as my last stage, after the mainsails have gone, and it performed worse actually, twr was just too bad.

Well, a Mainsail (or any engine) can lift only so much; you can't just add another 10t of upper stage and still expect it to work. Those 10t have ramifications all the way down to the ground. The first thing to try is  to remove a corresponding amount of fuel from the previous stage (so the gross mass of the whole stack remains about the same), and see if that still leaves the previous stage with enough oomph to make it worthwhile.

 

  • Like 1

Share this post


Link to post
Share on other sites
  • 0
On 12/23/2018 at 10:44 AM, Foxster said:

You seem to have a probe core in there half way up. What's that for?

What are those black and white striped things below the RCS tank?

Probe core is there so I can keep SAS on when my pilot leaves the ship, and those things below rcs tank are from tac life support mod, food, water and stuff.

 

On 12/23/2018 at 1:32 PM, Laie said:

You say you want to meet a return ship on low Eve orbit... try to shift functionality from the Eve lifter to the return vessel in order to reduce the mass of your payload. RCS fuel & thrusters is an obvious candidate, but also: is it really necessary to land the heat shield on Eve and carry it back to orbit? And four parachutes, a large reaction wheel, and so on?

Yup, that would have been my next suggestion.

Well, a Mainsail (or any engine) can lift only so much; you can't just add another 10t of upper stage and still expect it to work. Those 10t have ramifications all the way down to the ground. The first thing to try is  to remove a corresponding amount of fuel from the previous stage (so the gross mass of the whole stack remains about the same), and see if that still leaves the previous stage with enough oomph to make it worthwhile.

 

Thank you both for answering, I finally managed to get to orbit :D

Share this post


Link to post
Share on other sites
  • 0

How many delta v you still get ? if you get 1500 m/s you can just leave orbit already, no rendezvous needed.

Share this post


Link to post
Share on other sites
  • 0
15 hours ago, GRS said:

How many delta v you still get ? if you get 1500 m/s you can just leave orbit already, no rendezvous needed.

Fuel tank is almost empty by the time i get into orbit :D
And besides, I still need to dock because all the food and water is on the mothership

Edited by Cannon

Share this post


Link to post
Share on other sites
  • 0

so, are you using live support ? because i didn't, i reached orbit with like 3400 m/s delta eve, so...no docking needed, end up wasting fuel in the return :D, you can still use a Mk1 pod with a Mk1 passenger cabin to get 3 seats.

Share this post


Link to post
Share on other sites
  • 0
On 12/25/2018 at 3:47 AM, Cannon said:

Probe core is there so I can keep SAS on when my pilot leaves the ship, and those things below rcs tank are from tac life support mod, food, water and stuff.

 Thank you both for answering, I finally managed to get to orbit :D

Leave all the TAC stuff on ground, you have enough for an multi year mission anyway. 
Use an MK1+the two man 1.25 m crew cabin as other says. nose cone on MK1, you can put an docking port below. 
No RCS, or only RCS for boosters. Use the mother-ship to dock. 

I prefer chairs inside fairing but that is kind of an exploit. You can replace the booster tops with fairings holding stuff but again drop air brakes and shutes before takeoff. 

Share this post


Link to post
Share on other sites
  • 0
43 minutes ago, magnemoe said:

Leave all the TAC stuff on ground, you have enough for an multi year mission anyway. 
Use an MK1+the two man 1.25 m crew cabin as other says. nose cone on MK1, you can put an docking port below. 
No RCS, or only RCS for boosters. Use the mother-ship to dock. 

I prefer chairs inside fairing but that is kind of an exploit. You can replace the booster tops with fairings holding stuff but again drop air brakes and shutes before takeoff. 

The pod can usually store enough food for just a few days, definitely wouldn't be enough to get back to kerbin, keeping all the food is a must.

Share this post


Link to post
Share on other sites
  • 0
1 hour ago, Cannon said:

The pod can usually store enough food for just a few days, definitely wouldn't be enough to get back to kerbin, keeping all the food is a must.

You only need enough life support to get to orbit. A mothership can have a cache for a return journey. 

Share this post


Link to post
Share on other sites
  • 0
On 12/26/2018 at 7:08 AM, Foxster said:

You only need enough life support to get to orbit. A mothership can have a cache for a return journey. 

Yup, that's what I did :D

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now