Is a kerbo-synchronous space station a good idea?

[WhiteWeasel]

In light of the new patch and discovering that the new ASAS is a bit harder to work with and aerospikes are worthless. After learning around that I decided to build my first modular space station. But everyone has done that. I want mine to stand out a little. A kerbo-synchronous one is one I haven't seen yet. Should I try it?

[TheRabbit]

It might be hard and eat up fuel, but sure! Go for it.

[regex]

It'll take more delta-V to get to it, but it's definitely doable. I've done a Mun station before and I think they're more useful, but a synchronous station would be pretty cool.

[Sigma117]

I plan on setting up a station in Geosynch above the KSC at some point. Though I wouldn't make it modular myself.

[lammatt]

no i dont think so... 380km is pretty high indeed

and it's not very fuel efficient to have your ships refuel there

[NASI Director]

no i dont think so... 380km is pretty high indeed

and it's not very fuel efficient to have your ships refuel there

A kerbosync orbit ~2868km. Anyway, if you think you have the fuel and the patience, I'd do it.

[Kimberly]

Is there any particular reason (from a roleplaying point of view) you might want to place a station in a geosynchronous orbit?

[OrbitusII]

A Keo-synchronous space station would be good for things like RemoteTech, but I've been building my space stations at around 90km since I'm now confident enough to do a launch straight to rendezvous (got within 200m in under 20 game minutes).

[Scorpi15]

If you have a base launcher then if you want to launch to the space station it would always be in the perfect position for a rendevouz if you circularise the station as soon as you reach kerbosync altitude.

[SkyRender]

If the launch and circularization is timed right, a geosynchronous station can be a huge boon for "set it and forget it" intercepts. Such a station will always, without fail, be in position for you to launch to it straight from KSC, no matter the time of day. I actually had such a station once, for my ill-fated first Kerbal Tourist Program.

[Delling]

Well, I built this in .18 in sync orbit I believe:

It ended up more or less straight above the space center making it an excellent comm hub for RemoteTech.

Having it in one position makes rendezvous very simple, so I've used it as standard (main) station position a few times.

[WhiteWeasel]

I might have to wait for mechjeb to get updated then because getting a rendezvous at that altitude might be a bit hard.

[WhiteWeasel]

UPDATE: I got the core, habitation and boost modules in synchronous orbit!

Time for the communications & RCS tower and solar array to be added.

[Diche Bach]

I've managed several geo-stationary orbits but what is the trick to getting them synchronized over a specific spot such as KSC?

[SkyRender]

I've managed several geo-stationary orbits but what is the trick to getting them synchronized over a specific spot such as KSC?

The key is to control your oorbital period: don't raise your orbit to full geosynchronous until you're exactly where you want to be. Instead, bring your apoapsis up to the appropriate height, and adjust your periapsis so that you'll be in position next time you reach apoapsis. How do you do this? By tracing the period of your orbit: the time from apoapsis back to apoapsis. Then just factor in how far away your target location is when you reach AP, adjust for the 6-hour sidereal day of Kerbin, and you'll come up with an ideal period for your orbit so you'll get back to AP with your target location below. Once you get back to that point, then circularize. For example, say KSC is about 1/3rd of the planet to the east of where you are when you get up to geosynchronous, and you want to be right over it. Make your period 4 hours, and you'll be right over it when you get back to apoapsis next time. Easy!

EDIT: A useful tip: Your time from apoapsis to apoapsis is always twice that of your time from apoapsis to periapsis. So you can just look at time to periapsis when you reach apoapsis and multiply by 2 when doing your adjustments.

Edited August 1, 2013 by SkyRender

[KerbMav]

Is there any particular reason (from a roleplaying point of view) you might want to place a station in a geosynchronous orbit?

Purely roleplaying?

- Stable communication without any relays which can fail and would need a repair mission, on ground and station repair crews are readily available and on location - this is basically also the reason for several points below

- Combined surveillance and countermeasures in one location being always in range to observe/intercept/shoot down bandits/asteroids

- Remote military HQ to coordinate planetbound forces

- bugproof point-to-point communication

- Space traffic surveillance and guidance

- an always "home is not far" feeling for longterm stationed personnal

- political prowess "whenever you look up, my dear citizens ... yadayadayada"

[Ahmed]

Hmm, You can always move your station to lower or higher orbit after creating it, if you want. Station should be almost symmetrical if there is plan to move it. Build station on 120km orbit, add some propulsion, move to keosynchronous orbit. There is always way back to lower plane or going to moon orbit if u want....

[KerbMav]

-shorten-

You just sparked a design in my mind - a whole space station spreading its wings (solar panels) and gracefully rising higher above the sparkling blue oceans of Kerbin on streams of light (ion drives) ...

[Diche Bach]

The key is to control your oorbital period: don't raise your orbit to full geosynchronous until you're exactly where you want to be. Instead, bring your apoapsis up to the appropriate height, and adjust your periapsis so that you'll be in position next time you reach apoapsis. How do you do this? By tracing the period of your orbit: the time from apoapsis back to apoapsis. Then just factor in how far away your target location is when you reach AP, adjust for the 6-hour sidereal day of Kerbin, and you'll come up with an ideal period for your orbit so you'll get back to AP with your target location below. Once you get back to that point, then circularize. For example, say KSC is about 1/3rd of the planet to the east of where you are when you get up to geosynchronous, and you want to be right over it. Make your period 4 hours, and you'll be right over it when you get back to apoapsis next time. Easy!

EDIT: A useful tip: Your time from apoapsis to apoapsis is always twice that of your time from apoapsis to periapsis. So you can just look at time to periapsis when you reach apoapsis and multiply by 2 when doing your adjustments.

Cool, thanks. I figured it was something along those lines and I can't say I fully intuit what you are saying, but with these pointers I should be able to get it sorted out

I did have one of my 5 or 6 geosynchronous ones that I sent up that just by random chance wound up pretty much right over KSC.

However, I think none of my "geosynchronous orbits" so far have really been perfect as they all seem to be slowly drifting around. Really does need to be EXACTLY 0.0 m/s relative to surface doesn't it?

As far as the "directly above" stationary part, are these things in RL LITERALLY directly above? Or is it really more like they are within a narrow band (say a 1km wide section of the equatorial orbit?)?

[SkyRender]

The important thing is not your apoapsis or your periapsis, but your semi-major axis (the average between the two). Get that as close as possible to 2,868,750m and you won't drift as badly. Real-world satellites in the Clarke Belt have tolerance ranges. If the signal hits outside that range, they perform automatic adjustment maneuvers to get back into tolerance range. These frequent maneuvers eventually expend all useful fuel from them, and they eventually get retired by raising their orbit above the Clarke Belt into the Graveyard Orbit.

Edited August 1, 2013 by SkyRender

[Kaa253]

If you use the kethane mod to source fuel off-world and have ships coming and going into the Kerbin system from interplanetary space (sometimes returning with full tanks) then it makes sense to have a fuel dump station in a high orbit well outside Kerbin's deep gravity well. I have a refueling station high above Minmus' kethane mining fields. From there it requires little delta-v to break free into a Kerbol (solar) orbit. I use the high Isp LV-N atomic motor and ion drives a lot. I have been running pseudo "Buzz Aldrin" cycler trips between Kerbin and Duna. Sure, there are roleplay reasons for all of this, as currently fuel is still "free" at KSP launch centre. I like the idea of a kerbosync orbit station very much but I have always had problems with drift. Thanks for the tips SkyRender. I will try it again.