Remote Tech grief

[Tux]

I have 4 sats in a 2,500km equatorial orbit and 1 sat in polar orbit. The network is working but its unstable and uneven.

I have MechJeb and actually in this case prefer to use it however I haven't been able to successfully fine tune my orbits and distances between sats very well at all manually or with MechJeb.

So I am looking for a tutorial to get those fine tuned with MechJeb and/or a tutorial on how to simply be a fantastic pilot able to land craft on a dime.

Thanks

[The_Rocketeer]

Don't forget that your orbit altitude doesn't account for the 600,000m radius of Kerbin. You need to add that to your altitude when working out satellite separation distances (using Pythagoras).

Fine tuning orbits means using very low thrust levels. RCS thrusters are ideal, though MechJeb won't use them for primary thrust. PreciseNode is also a mod I would recommend for precision's sake.

However, it's worth remembering that however precise you get your orbits, they'll eventually drift out of position due to rounding errors in the game's orbit equations. In general, you're better off making a grid of Geostationary Relays that can cover the whole surface. It's also a good idea to add permanent surface relays (with dishes to target the GSO relays) on the North and South poles - this removes the need for polar orbits.

Edited November 25, 2014 by The_Rocketeer

[Tux]

Don't forget that your orbit altitude doesn't account for the 600,000m radius of Kerbin. You need to add that to your altitude when working out satellite separation distances (using Pythagoras).

Fine tuning orbits means using very low thrust levels. RCS thrusters are ideal, though MechJeb won't use them for primary thrust. PreciseNode is also a mod I would recommend for precision's sake.

However, it's worth remembering that however precise you get your orbits, they'll eventually drift out of position due to rounding errors in the game's orbit equations. In general, you're better off making a grid of Geostationary Relays that can cover the whole surface. It's also a good idea to add permanent surface relays (with dishes to target the GSO relays) on the North and South poles - this removes the need for polar orbits.

can you rephrase what you are saying in bold. I think I understand but not completely sure

[The_Rocketeer]

Geostationary orbit is a circular equatorial orbit where the orbital period (the time to complete one full orbit) is the same as the interval of one rotation of the planet below, i.e. a day. On Kerbin this is just a shade over 6 hours. The result is that the satellite appears not to move and is always directly above one place on the surface, meaning this satellite can always stay in contact with KSC, forever. With three such satellites, equally spaced around the planet, you can cover almost the entire surface of the planet with a reasonable degree of overlap - this is the minimum number of satellites to ensure continual coverage at the equator, but you could use more.

There may still be places close to the poles that can not always draw line-of-sight to a satellite in an equatorial geostationary orbit, mainly because a satellite in equatorial orbit seen from the poles will appear to be very close to the horizon, and the surface of a planet has hills and mountains that might get in the way. Consequently, placing bases very close to the poles with a dish to track whichever of the geostationary relay satellites is not obscured by mountains should ensure that you should always have a connection back to KSC, as the targetted satellite will never move and become obscured, and will relay signals with the other GS satellites, one of which will be in contact with KSC.

(Edit: had to change the underlined part because being very tired made me be dim.)

By also outfitting these bases with antennas, you can extend the relayed signal to crafts within a radius of the pole that can draw line-of-sight to the base. If they are far enough away that the polar relay base is over the horizon, then they should already be far enough south to receive directly from the satellite relays. If you find this isn't the case, you can boost the surface range by building your antenna on the top of a radio tower to extend it's coverage.

Hope that clears it up a bit.

Edited November 25, 2014 by The_Rocketeer

[cantab]

Remember, the important thing is your orbital period. Nail that as precisely as you can and your satellites will hardly drift in the long term, even if the orbit is a little eccentric and inclined.

[Tux]

Am I to understand from both The_Rocketeer and cantab, that if I get my sats in a Geostationary orbit that this will provide me with much progress toward stablity

[cantab]

A geostationary orbit generally helps, yes. Satellites with a view of KSC will retain that connection, and the relative positions won't change.

[Tux]

THANKS GUYS!

Understanding GEO solved my problems and made my life so much easier

Clearly Bar Kerman as mission control should have been spending more time reading manuals rather than eating snacks

[tomf]

There isn't really any reason to have them in a stationary orbit. My constelation consists of 3 satellites in a 700km orbit which use comm-16 antenat to keep in contact with each other, the ground station and provide signal to all of space around kerbin. As long as they are inclined reaseonably close to the equator and their semi-major axes are the same this will provide perfect coverage.

[The_Rocketeer]

This is technically true, but having a single permanent uplink satellite in GSO can be a great advantage over a number that change position. If you're going to put one in GSO then the most efficient way is to put only two other satellites up, also in GSO.

Also, being further away means the sats will be higher on the horizon from the poles, so less likely to have blind-spots.

Personally, I tend to keep at least one master uplink in GSO and still build networks at lower altitude for GPS-style connections.

It really depends whether you're going for finesse and detail or if you just want to get something up that works.