Best altitude for ease of rendezvous

[Jestersage]

As title. If my parking orbit is usually around 80x80, what is the best altitude for a space station? What about parking orbit at 100?

[Aegolius13]

I don't think it matters that much.   You'll want it a little higher than 70km, so you can dip lower to speed up your orbit.   Some people like a higher orbit for faster time warp,  but you can always go to the tracking station for that.

Lower means more Oberth, but if your ships refuel at the station, a higherror orbit will generally give the ships greater range (up to a limit called a "gate orbit.")

My Kerbin station is about 100k, but that's pretty arbitrary.   

 

[bewing]

It kinda depends on your favorite rendezvous technique, and how much fuel you are willing to spend being inefficient -- vs. how much time you are willing to sit and stare at the screen while waiting for orbits to converge.

I like having my stations from 100 to 120km. I can easily create an orbit below that that will usually catch up to the station within 1 or 2 orbits, if I'm behind it. Creating an orbit above a station is always easy because you have all of space to work with. If you go much higher than that, you start having deltaV problems with the actual rendezvous. And if you detach something from the station for reentry, if your station is much higher than that you build up an annoying amount of speed while descending.

A lower orbit for your station will mean more fuel efficiency, in general -- but worse coriolis effects when docking, and it takes many more orbits for a ship to catch up to the station (because their speeds are much more similar).

[Snark]

Yeah, it basically doesn't matter what your altitude is in terms of ease of rendezvous, as long as it's not so low it's skimming the atmosphere.  Pick the height for your station that's convenient for you for other purposes, and go with that.

Plenty of "best height for a space station?" threads out there.    There's no one correct answer, it depends on what you want to do and also on personal tastes.

Some people like "a little over 120K" so they can get 100x timewarp.  Some people like "a little over 160K" so they're above the big heavy slow Kerbin texture transition.  Some people like "a bit over 240K" so they can go to 1000x timewarp.  It's all a matter of taste.

[Superfluous J]

The only altitude I would not put a station is 100km, because that's the in-game boundary between near the planet and far from it, at least at Kerbin. This doesn't matter much anymore but I'm an odd mix of sentimental and superstitious. There was a very light wonkiness somtimes as you crossed that 100km boundary.

I personally prefer 80km because I like it low. I also sometimes do just over 100km, like 105 or so.

One interesting thing is if you are going to be doing a lot of interplanetary returns and exits (like Hermes in The Martian was going to do) then you may want to look into the concept of the Gate Orbit. It helps a bit justifying the extra dV (and therefore fuel) required to get to a higher orbit.

[Whisky Tango Foxtrot]

I keep my station at 250km, mostly for time warp purposes but also because it gives me lots of room to catch up to the station from below. If I'm returning to Kerbin from elsewhere my PE is likely going to be around 45-50km due to aerobraking, but lowering your AP is essentially free, so I'd rather be able to circularize into a low orbit to catch up with the station than have to raise that PE into a high orbit to let it catch up with me.

[Jestersage]

7 hours ago, 5thHorseman said:

One interesting thing is if you are going to be doing a lot of interplanetary returns and exits (like Hermes in The Martian was going to do) then you may want to look into the concept of the Gate Orbit. It helps a bit justifying the extra dV (and therefore fuel) required to get to a higher orbit.

Can you point me to the threads about the Gate Orbit?

[Superfluous J]

1 hour ago, Jestersage said:

Can you point me to the threads about the Gate Orbit?

Here are two old ones with mentions:

 

[agrasyuk]

so far I tend to park stations and interplanetary ships at 100Km. most of reasons were mentioned above - I really like that round number, not to hard to get to, good window for lower catch-up orbits, etc.  

[Vanamonde]

The lower you are the faster you are moving, and so the larger the relative motions will be at the time of rendezvous. Meet-ups at lower altitudes happen faster and require stronger burns, so higher is easier. But not a lot easier unless you go for a really high orbit, which may not be worthwhile. 

[fourfa]

I put my station at 165km for the texture/lag reasons mentioned. I've noticed that from any position in an 80km orbit, it's never more than 7 orbits before a good Hohmann transfer. Lower, you will sometimes have to wait longer. Higher, not as long. 

There are real and much-debated advantages to various orbital heights when you compete for bragging rights on dead-minimum dV count for interplanetary burns. And that can be a fun hobby. But in terms of basic general-purpose ship design, it's too small to care about. 

Subjectively, I like the view of Kerbin from 150-200km the best. Enough curvature to be dramatic, but not too much. I usually head there for screenshots. 

Edited March 10, 2017 by fourfa

[FleshJeb]

I park my Kerbin stations at 291km, because that's 1.5x the orbital period of my standard 80km orbit. They have frequent rendezvous windows; are low enough to be cheap to refuel; are low enough to depart interplanetary from; and you get 1000x timewarp.

  https://en.wikipedia.org/wiki/Orbital_period

http://wiki.kerbalspaceprogram.com/wiki/Kerbin Necessary info on the side.

[FancyMouse]

I do 80km because it's easier to do a direct launch-to-rendezvous, and requires less for my SSTO.

[Curveball Anders]

On 2017-03-10 at 7:12 AM, FleshJeb said:

I park my Kerbin stations at 291km, because that's 1.5x the orbital period of my standard 80km orbit. They have frequent rendezvous windows; are low enough to be cheap to refuel; are low enough to depart interplanetary from; and you get 1000x timewarp.

  https://en.wikipedia.org/wiki/Orbital_period

http://wiki.kerbalspaceprogram.com/wiki/Kerbin Necessary info on the side.

Big thanks for this, just what I needed.

(My cheezy desk calculator refused cube roots so I had to write a program (math in C, eugh ...) to solve it.)

From now on I will go for 284.5 km orbit for stations since I prefer a launch orbit of 75k for all launches, and with the station (or other parked gadgets) its perfect at 1.5x orbital time.

Edited March 11, 2017 by Curveball Anders