What is the best inclination for this station?

[animalcross]

I'm currently setting up a Kethane mining colony on the Mun, yet I'm not sure weather the station should be on an incline, forcing incoming ships to adjust their inclination or having landers to adjust the inclination, I would like to have some feedback on which is the better option.

I apologize for the large image, couldn't get the spoiler working.

[JaySmoka]

Which one will be more frequent: Landers departing and coming back to station or ships arriving and departing of your station? Probably lander will have to go to you station more frequently. Don't know which way will be more efficient, but in my program, landers have less fuel, less rcs so more possibility to do unrecoverable error. IMO I'll go with the station inclined.

[animalcross]

That's a hard question, my colony only has one module right now and I can expect at least a dozen coming in, plus remember each one has to come in from Kerbin which means it swaps from my SpaceTUG to the landing vehicle at the station.

EDIT, my lander has 3k DeltaV without any cargo, after landing it has around 1.5k, yet the inclination change alone takes around 500. Its more of a question of convenience for me landing the cargo and not having to perfectly line up the inclination every time or risking incoming spacecraft and having rescue missions.

Edited June 19, 2013 by animalcross

[HoY]

IMO it's best to keep the station at 0 degrees,, if you keep it orbiting inclined to pass over the base you will only have a single launch window every munar rotation.

The way I launch my tankers from non equatorial sites is launch to 0 degrees, and burn your standard ascent profile until you have an apoapsis that crosses the equator. Kill the burn then make a node on the AP, have that single node adjust your inclination to 0 and circularize at the same time.

In mechjeb terms, launch to zero inclination, start turn 500m above whatever your current alt is, turn end altitude of about 3-4 km higher than that. Target altitude of 100km higher than your station orbit altitude. Auto Warp Off toggled.

As soon as it stops burning disengage ascent guidance and open maneuver planner. Tab over to change inclination. Set to zero. Planned time at at next eq dn

Now edit this node either manually or with maneuver node editor to also circularize the orbit.

Press execute next maneuver.

You can rendezvous manually or automatically from there

[MBobrik]

inclined low orbit

PRO:

- far less dV.

CON:

- launch window only once when your orbit just touches the site or twice when your inclination is higher. However, by a small change of inclination during landing/ascent you might be able to launch during say 20 - 25 % of Muns rotation.

- incoming/outgoing ships will have to change their inclination, however this dV cost is negligible when done sufficiently far away

Low equatorial orbit

PRO

- you can come up/down pretty much any time

CON

- you pay all the dV costs of high inclination change, which may be well over 300 m/s

High equatorial orbit

PRO

- the higher up you go the less dV inclination change will cost you, faces however diminishing returns, as landing and taking off will cost more dV

CON

- It is so slow that you may wait comparably long to a launch window as with the the inclined orbit

- very little help from oberth effect when leaving/entering orbit

Edited June 19, 2013 by MBobrik

[purpletarget]

The upshot of having a refueling base on the Mun, is that you don't need to worry about getting more fuel shipped in from elsewhere. So it would make more sense to leave the station as is, and let the landers do the inclination adjustments. Bulk them up a bit if you need to pack on the extra 1km/s or so they'll need for a round trip with payload. Who cares if they use a little extra gas...they can top up when they get back to the base, and then fill cargoes. How much are the arrivals (presumably larger ships) at the station going to need to get back on the transfer plane once they're done collecting their cargos?

[Syhrus]

The problem with inclining your station's orbit is that it doesn't take into account that Mun will be spinning. So while you will be lined up correctly when in the same position as shown in your picture, you will be even further out of phase half a Mun day later when the station is on the other side of the planet.

For my mining operation, I have a colony on minmus, and fly kethane up to an orbiting tanker using a lander. Then I fly the tanker back to Kerbal where it docks with a refueling station that does all the refining work. This works well even though my actual mine is on 10° latitude and I have the tanker orbiting at nearly 0. It really just depends on how you want to do it. If I were you, I'd use the same system, keep the station at 0° and just use a lander with a high amount of dV.

[animalcross]

Yeah now that I think about it, the lander preforming the change makes the most sense, since It has tons of DeltaV and incoming rockets may not have as much depending on their loads.