Delta V requirements for a 3 moon tour

[Rakaydos]

So I recently built a SSTO tylo lander/return vehical, with all the massive delta V that requires. However, what I wnt to attempt now will push the limits of that delta V, so I want someone to check my orbital dynamics- my first attempt tried to brute force the question, and it failed.

My mothership can lift the lander to Tylo escape and into a Vall intercept, over several orbits. Decoupling, the mothership alter's course to a val slingshot, to generate a Layth intercept.

The lander needs enough delta V to suicide burn on Vall and return, generate a Tylo slingshot for the inclination to hit Bop, suicide burn there, intercept Pol at the inclination node for a third suicide burn, then drop for a tylo slingshot into a layth intercept for refueling.

assuming perfect hoffman transfers and perfect suicide burns, (the tylo lander has very high TWR for landing burns) can I manage this mini-tour with my lander's 6k Delta V?

[Tortoise]

Heres this for reference.

[Red Iron Crown]

I like metaphor's one better for puttering around the Jool system:

6km/s looks pretty marginal.

Edit: Oops, I misread your mission profile, 6km/s sounds like plenty.

Edited May 30, 2014 by Red Iron Crown

[Mr Shifty]

Using Alexmun's launch window planner, I can give you very rough numbers.

Looks like:

- 250 m/s insertion burn into Vall orbit

- You have to kill about 720 m/s of orbital velocity to land on Vall (and its rotation is so slow it doesn't matter.)

- Another 720 m/s to achieve orbit again.

- Getting intercept with Tylo again costs about 250 m/s minimum

- When going from Tylo to Bop, the insertion burn is going to cost about 500 m/s

- Suicide burn to Bop is about 125 m/s.

- Another 125 m/s to get to orbit again.

- Bop to Pol is about 490 m/s

- Land/take-off Pol is about 70 m/s each way.

- Tylo intercept is another 200 m/s or so

- Should be able to aerocapture to Laythe.

Total: 250 + 720 + 720 + 250 + 500 + 125 + 125 + 490 + 70 + 70 + 200 = 3520 m/s

So 6 km/s should give you lots of extra for the inevitable landing inefficiencies/orbit manipulation/etc.

[Kasuha]

Either of the two dv maps above is IMO very misleading in Jool system. The inner system moons - Laythe, Vall, and Tylo - have so large SOIs and are so close to Jool that dynamics caused by game implementation (SOI/patched conics) make transfers between them almost free - the only 'regular' part is going between surface and orbit which crosses its SOI.

When you raise your apoapsis to just barely exit Laythe, Vall, or Tylo SOI at the right place, you can get into orbit that crosses orbit of either of the two other moons. No transfer dv needed. From Tylo, you can get almost to Bop this way as well. And if you learn to (ab)use Tylo gravity slingshot, you can even return to Kerbin for almost no dv spent.

Also when you prepare your transfer so it goes low above the surface of your target, you can save significant amount of dv on capturing/escape thanks to Oberth effect.

Looking at both maps and comparing them with my experience, the only realistic numbers are dv to reach orbit. Except for Laythe where you can use way less if you have a spaceplane.

Do NOT trust dv maps. Especially in Jool system.