Interplanetary transfers

[Good_Cat]

I've been playing KSP for 500 hours and a smidge, but never really gone outside Kerbin's SOI, too much time playing with SpaceStations and BD Armoury.

I've got a ship in a 100km Orbit round Kerbin where is the easiest place to go (for someone new to going interplanetary), I've seen Moho and Dres transfers pop up regularly with KAC but Moho looks like it could be a nightmare with its inclination, high orbital speed and Dres its inclination again.

I flown by Duna and Ike with probes and a manned fly-by of Moho that almost turned into a total disaster, Kerbin return, with a whole 91ms dv left and and had to use RCS in the other side of the solar system to tweak the encounter which was pure luck until i had an impact trajectory then use RCS again to burn radial at Kerbin SOI until the PE was 30k.

Since I've mostly played in Kerbin's SOI I've never really used Nuke's either.

Oh and does the TWR matter in vacuum does a TWR of below 1 use more dv from the potential in the tank than is actually given in velocity

Screenshot (Using Procedural Tanks and VenStoackReVamp and Tweakscale)

Staging got a little screwed up and my nukes got activated the same time as the poodle at the rear.

Rough DV is

Stage 5 Poodle 1270ms,

Stage 4 Centre Nuke + 4 Outer Nukes(tweakscaled) 4890 with Fuel lines leading to the centre stage,

Stage 3 Centre Nuke 3279ms

Stage 2 is the Lander separated from the Nuke Probe with 2026ms

Nuke Probe is fitted with a Probe Core and Docking Port so the Lander can re-dock.

[NASAHireMe]

It looks like you have plenty of dV to go interplanetary. And the fact that you have already done a Moho flyby is impressive. Even without capturing at Moho (which requires a boatload of dV), getting to Moho, with its inclination and distance, is still an accomplishment.

TWR does not really matter in vacuum, although in practice having a TWR lower than 0.2 tends to be agonizing since burns take 5+ minutes of time. If your TWR is lower than 0.2 (or whatever you're comfortable with), slap on a few more engines in the VAB.

And no, your dV is your dV. It is, by definition, the end result of the change in your velocity. Usually, because nukes are so efficient, most medium-to-large interplanetary crafts will have low TWR, typically around 0.2 (again, see above on why going below 0.2 starts to get annoying).

[Geschosskopf]

I've got a ship in a 100km Orbit round Kerbin where is the easiest place to go

...

Oh and does the TWR matter in vacuum does a TWR of below 1 use more dv from the potential in the tank than is actually given in velocity

Well, with nearly 9000m/s in the tank, you can do a round trip to just about anywhere so take your pick. It's all pretty much the same, just wait for the window, point in the right direction, and burn. Interplanetary isn't nearly as hard as many think. So go tour all the moons of Jool, as that's the most interesting visuals we got .

The TWR thing, however, might require a bit of tinkering during the departure burn. TWR depends on the planet you're orbiting but at Kerbin, a TWR of about 0.75 means about a 5-6minute burn. This is about the lower limit on TWR for doing an efficient burn in 1 shot. With a TWR of only 0.26 or so, expect a 15-20 minute burn. This is NOT the way to go because it only takes 20 minutes to orbit Kerbin at 100km, meaning that most of the time you're nowhere near your node if you try to burn all at once.

So instead, break the burn up into however many 3-5 minute chunks you can live with, each done on successive orbits. Note, however, that once you reach 1000m/s of the burn, your Ap will be out around Minmus, meaning an orbit back to your Pe burn point will take several days to complete, which can screw up your window slightly. However, this is nothing a minor mid-course tweak can't fix en route.

[Good_Cat]

Cheers gents, i'll wait for Duna and maybe land on Ike, next time i'll adjust my e

scape stage TWR so its higher i see wait you mean about the low TWR for escaping a SOI.

Not going to Moho again that crew of 7 managed to return on the sheer luck of a half decent encounter i was lucky to find. Saying that Jeb and Val weren't on that mission i found them on my Minmus Station......must have sneaked into the capsule when i wasn't looking.

[Chaos_Klaus]

Oh and does the TWR matter in vacuum does a TWR of below 1 use more dv from the potential in the tank than is actually given in velocity

Thrust to weight is only important whe you are fighting gravity to not fall back onto the surface. It's not about vacuum or atmo. It's about gravity or no gravity. That's why we tend to do our burns parallel to the surface ... there is no gravity drag then.

[Good_Cat]

Thrust to weight is only important whe you are fighting gravity to not fall back onto the surface. It's not about vacuum or atmo. It's about gravity or no gravity. That's why we tend to do our burns parallel to the surface ... there is no gravity drag then.

Cheers, i didn't think i would matter but had to check.

[Good_Cat]

Thanks for the help gents, for my first Interplanetary landing i did.....Eeloo. Not my brightest but all the other transfer windows were ages way and all the others came and went while i was still on my way there :S. However I managed to orbit, land, plant the flags, re-orbit, re-docked to the transfer, and returned to Kerbin's SOI with 700m/s dv still in the transfer tank, still came into atmo a little on the hot side of 3200m/s but still successful. (4400 science and 31xp for both Jeb and Val.)

Tweaked the escape stage for better TWR and bigger solar panels for high solar orbits (ran out of lecky and took forever to charge) and moved then on the centre nuke not the disposable outer tanks:S

Did have to cheat and HyperEdit my lecky supply at Eeloo, i ran out totally, need RTG's or as above bigger solar panels.

Plant a flag on the Sun next......Jeb's idea.