Rendezvous

[KvickFlygarn87]

Hello!

I think I have docking figured out, but I can not for the life of me rendezvous. I hope you guys can help by answering a few questions.

1. What is a good height for the docking target? In this case a station.

2. What is a good parking orbit?

3. How do I set up my maneuver?

4. How do I know if the orbit I'm on can give me a good transfer?

Thank you,

Kvick

[Tex_NL]

Check out this in-game tutorial: http://forum.kerbalspaceprogram.com/threads/46232-0-21-1-Rendezvous-Tutorial-1-1-0

[blizzy78]

1. What is a good height for the docking target? In this case a station.

2. What is a good parking orbit?

It all depends on what you're trying to accomplish. If you're going for a reasonable time frame, it's best to go for orbits that give you close encounters (shortest distance between the vessels on their orbits) quite often. For example, if the orbits of the two vessels are only 5 km apart, it can take a long time to timewarp to a reasonable transfer window. I'd recommend the target being at 200-250 km, and the docking vessel at a 100 km parking orbit (or vice versa.) Those orbits give plenty of transfer windows.

[KvickFlygarn87]

Tez: I have, it's great, but apparently I'm stupid.

Blizzy: Thanks for the support!

[Kulebron]

Click on orbit in map view and change the parameters. In two words, if you go higher, you go slower, and vice versa. If you want to catch up and are far enough (20 km), it's better to break and get a slightly lower orbit and to catch up 1/2 orbit later, than to thrust directly at target.

To be able to catch up with station, its orbit has to be higher than 80 km. 100 is quite enough, >120 is good for time warp. Anyway you need to fly higer than atmosphere.

Any orbit that is close to target's orbit is good, the shallower the angle betweer them, the better (means less speed difference, less thrust needed to match speeds).

[KvickFlygarn87]

I really need the help, I wanna make my station!

[nhnifong]

remember, orbit lower to catch up, orbit higher to wait around.

[Kasuha]

1. What is a good height for the docking target? In this case a station.

Criteria to consider when selecting orbit for your station:

- Lowest undisturbed orbit is above 70 km (assuming Kerbin).

- It is good to allow both lower and higher orbits for ships to make rendezvous.

- Time Warp thresholds are at 120 km and 240 km. The higher time warp you want to use with the station the higher orbit you need to use.

- Too high orbit may be hard to reach and may require more powerful rockets.

My own station is at 150 km and I am happy with it.

2. What is a good parking orbit?

3. How do I set up my maneuver?

4. How do I know if the orbit I'm on can give me a good transfer?

When going at the station from the ground, the best is to wait for launch window and go directly at the station's orbit to meet it there.

When going from elsewhere (or if you didn't meet the optimum launch time, screwed up ascent etc), just make the orbit lower or higher, higher if you're ahead of the station, lower if you're behind. Good idea is to make it elliptical so it touches the station's orbit with one end and gives you approach distances.

For example (assuming station at 150 km) - if you're behind, make orbit with PA at 75 km and AA at 150 km. If you're ahead, make the orbit with PA at 150 km and AA at 200 km.

In any case make sure the orbital planes match.

When you come at the station's height and pass the current approach mark, so the next approach appears, you can burn prograde or retrograde to adjust the orbit so you meet the station the next orbit. Or you can wait a few orbits if the distance is too great and it would require too much dv (or if you'd need to reduce your PA below 70 km).

[SRV Ron]

Higher to slow down, lower to speed up. Do so in as closely matching orbit as possible. Take your time, do small burns, switch to thrusters for fine tuning. Keep in mind that such maneuvering for real often takes hours and involves speeds well under 1 meter a second.

I matched orbits with two ships around Mun just because I got close enough when doing the initial orbit. It is tedious but requires patience. Would have fine tuned it further but the ships didn't have the capability for lateral thrusting.

I eventually had the target speed down to 0.1 m/sec.

Edited September 30, 2013 by SRV Ron