Satellite contracts with MechJeb

[OscarJade]

All right, I guess I surrender. Having an impossible time trying to get satellites into the orbit required. I couldn't do it without MechJeb, and I can't do it with MechJeb. Do I need to circularize first, then do apoapsis, then periapsis, then inclination and finally longitude of ascending node?? I'm not even sure how to plug in the numbers for the latter. Invariably I end up with an orbit that approximates what is called for, but is off in some way. Trying to execute my own radial, normal- or anti-normal burns seems to accomplish nothing. I guess I'm too slow for MechJeb even? The MechJeb autopilot, when used with ascent guidance, seems to take me into random encounters with the Mun etc if I call for the altitude of orbit asked for (18,692,804 meters, or about 18,692 k(?)). I'm open to pointers or suggestions; want to play the game properly but tempted to use the 'debug' key to cheat-complete all the satellite contracts I've foolishly take on. Suggestions are most welcome

[Pecan]

18Mm is between the orbits of Mun and Minmus, so a long way out for a direct launch.

How best to do things depends somewhat on the parameters of the orbit you've got to get into - inclination and so on - but in general:

1. Make sure you know which way around you're meant to go (follow the dots). A LOT of people don't.
   
2. Get to orbit! You know it makes sense and once in LKO you've got lots of time to mess about and plan. Launch into the correct inclination if possible (ie; when KSC is under the required orbit).
   
3. Match planes with the required orbit if you haven't already.
   
4. Orbital-altitude changes (prograde and retrograde burns) affect the OPPOSITE side of the orbit so, just by eye, create a manoeuvre node opposite the target apoapsis.
   
5. If you want more time to think, right-click the manoeuvre node then click the '+' button to advance it one whole orbit.
   
6. Pull the yellow prograde marker out so your projected apoapsis reaches the required altitude.
   
7. Now drag the centre circle of the manoeuvre node backwards/forwards along your orbit so the projected and required apoapsisisisis (plural??) meet. Move prograde in/out to adjust the project altitude as required.
   
8. Tell MJ to execute the burn, then circularise at apoapsis.
   

[Kryxal]

Often enough, I'll just launch into an equatorial orbit for those contracts with maybe 10-20 degrees inclination. I'll then drop the apoapsis on the AN or DN (whichever has more altitude) and match orbits once I get there. It's not the most efficient approach, but it's simple, one easy burn to intercept and one more complicated burn (set up by an iterative process, radial for plane change, pro/retro for matching orbit period, normal for laying the two on top of each other, rinse and repeat till it looks good).

[Hannu]

It is more effective to launch to right inclination. You can go to map view, focus to Kerbin, take side view so that target orbit and Mun's orbit crosses at center of kerbin. Then wait until KSC is on sigh line (you can see the icon of ship there). If it is target orbit's AN, put inclination (and typically 0.5-2 degrees addition) to Ascent guidance as a positive number. If it is DN, put negative inclination. Then launch to low orbit (about 100 km). You should get orbit with low angle between planes (0-2 degrees). After that it is easy to adjust apses and inclination. Orbits does not have to be accurate. If you have problems with that, are you sure that you orbit to right direction?

[Janos1986]

Ummm...

1) Wait until the KSC is at either the ascending or the descending node of the requested orbit, then launch. Start tilting your orbit in the atmosphere to gain some advantage.

2) Circularize at KEO and start to burn to an inclination roughly similar to the one you need, even if it's off by a couple degrees.

3) Burn to get the Ap to the requested altitude

4) Circularize again

5) Trim with normal and radial burns

6) ??

7) PROFIT!

I still can't stress enough the fact that satellite contracts are not hard at all.

When you have the amount of fuel you need, it's a piece of cake.

When I see satellite contracts at Mission Control I usually go "yay, free money".

Edited January 20, 2015 by Janos1986

[cicatrix]

Regardless of whether you want to save dV (by waiting for KSC to be on the AN or DN) here's a step-by-step guide making it as easy as possible:

1) Check the destination orbit if it's pro- or retrograde.

2) Check again - you want to launch either to the east or to the west depending on that. If the destination orbit inclination is less than 90 degree - launch east (or north-east if the inclination is big) and launch west if the destination orbit inclination is 90-180 degree.

3) Once in orbit - match the inclination - position the camera in such a way that both your orbit and desired orbits were looked like straight lines (not ellipses) - find the intersection - that's your AN or DN - put a maneuver node there and drag either normal+ or normal- until your orbits are on a single plane

4) Draw a line from the desired periapsis to the opposite point of your current orbit (draw a line from the desired AP to the center of the planet and further until it intersects with your current orbit) - put a maneuver node there and drag prograde until your AP is at the target PA. Burn

5) Put another node on your new AP and drag prograde until your orbits are the same.

6) Profit!

[Wanderfound]

Lotsa folks here saying to match inclination, then raise the orbit to the required height. You'll save a lot of fuel if you do it the other way around.

[cicatrix]

Lotsa folks here saying to match inclination, then raise the orbit to the required height. You'll save a lot of fuel if you do it the other way around.

Yes, indeed, but if your LANs do not match you'll end up in a completely different orbit. Besides, my satellites can probably go to Jool and back and even then they'll have fuel to complete the contract. (I take 5-6 sat contracts simultaneously and use a single satellite to complete them all). Easy money!

[Janos1986]

Lotsa folks here saying to match inclination, then raise the orbit to the required height. You'll save a lot of fuel if you do it the other way around.

Actually I found that starting to tilt to the right orbit during the gravity turn saves me fuel, since I spend almost (ALMOST) the same amount of dV as getting in a normal equatorial orbit.

Maybe it's just me, I'll have to put down some numbers.

[Hannu]

Actually I found that starting to tilt to the right orbit during the gravity turn saves me fuel, since I spend almost (ALMOST) the same amount of dV as getting in a normal equatorial orbit.

Maybe it's just me, I'll have to put down some numbers.

It is not just you. It is universal and rockets should always be launched to orbit with correct inclination and LAN, if possible. Kerbin's rotation gives 175 m/s. You can easily use more to large plane changes, even if you do them far away from Kerbin. It can also save considerable amounts of dv if you make interplanetary transfers from optimal orbit.

[Wanderfound]

Actually I found that starting to tilt to the right orbit during the gravity turn saves me fuel, since I spend almost (ALMOST) the same amount of dV as getting in a normal equatorial orbit.

Maybe it's just me, I'll have to put down some numbers.

Yes, it's always best to launch directly into the correct plane. However, when you do have to make an inclination change (e.g. using one probe for two contracts), it's much cheaper to do the inclination change as high as possible.

[cicatrix]

As I already said a correct LAN is probably more important than a correct inclination.

[Janos1986]

Yes, it's always best to launch directly into the correct plane. However, when you do have to make an inclination change (e.g. using one probe for two contracts), it's much cheaper to do the inclination change as high as possible.

Yeah, if dV and the antenna range (RMTech) allow it, I like to complete 2 or 3 contracts with the same satellite, which is usually worth about 15k-16k funds boosters included.

Last time I had both a surface outpost and a satellite orbit contract for Minmus, so I just took a five man lander and brought along a basic satellite with just a handful of dV (total weight 200-250 Kg if I recall correctly), solar panels, antenna and 2 small radial engines and completed both assignments in 15 real time minutes.

Note: even if the craft is manned at launch when the satellite decouples it checks again automatically.

As I was saying, easy money.

I'm just a million funds away from upgrading R&D to tier 3. About time.

Edited January 20, 2015 by Janos1986

[Wanderfound]

You can get a crazy amount of delta-V out of those ultralight probes:

[OscarJade]

Thanks so much, everyone! I can't wait to get home tonight to give it a try Still wrestling with the LAN thing and holding the takeoff vector to follow the inclination...I think I can plug it into MechJeb's guided ascent? Definitely didn't have any luck with the autopilot on launch...another question is plugging the desired LAN into MJ - there are three fields to fill and four digits in the number (although the last two are separated by a decimal point).

At any rate, I'm gratified by and thankful for the knowledge and generosity of this community. Will talk soon, I'm sure. Thanks again, and cheers!

[Fenra24]

Hey, newcomer here, figured I'd join in this conversation because I'm having the same issue with mine, only it's not that I *can't* make the appropriate orbit, but I am already in it, but it won't give me the contract completion. I mean, I know it's not exact, but it says within "marginal deviation" which honestly I don't know of a way to get this orbit any closer to the specifications, at least not with an LV-909 (which I have plenty of fuel to play around with thankfully). How exact must this orbit be in order to complete the contract? I'm well within the apaposis and perapisis requirements, and the inclination too. It shows ascending and descending nodes, which I don't know what that does/mean. If anyone can lend a hand, it'd be greatly appreciated

[Wanderfound]

Hey, newcomer here, figured I'd join in this conversation because I'm having the same issue with mine, only it's not that I *can't* make the appropriate orbit, but I am already in it, but it won't give me the contract completion. I mean, I know it's not exact, but it says within "marginal deviation" which honestly I don't know of a way to get this orbit any closer to the specifications, at least not with an LV-909 (which I have plenty of fuel to play around with thankfully). How exact must this orbit be in order to complete the contract? I'm well within the apaposis and perapisis requirements, and the inclination too. It shows ascending and descending nodes, which I don't know what that does/mean. If anyone can lend a hand, it'd be greatly appreciated

Check your inclination. You're almost certainly in the correct orbit but headed in the opposite direction to what is required. If you look closely at the required orbit in the map screen, you'll see little whizzy things zooming around showing the required direction.

If it's not that...

Do you have a solar panel? Do you have an antenna? Did you turn your SAS off and wait a few seconds?

[OscarJade]

Wow, unfortunately still just feel stupid. Guess I'll try to see if YouTube has anything I can actually watch. Guess I just don't comprehend. Thanks anyway, all I'm glad it's easy for so many.

[MarvinKitFox]

I still can't stress enough the fact that satellite contracts are not hard at all.

When you have the amount of fuel you need, it's a piece of cake.

When I see satellite contracts at Mission Control I usually go "yay, free money".

I usually gather 4-5 satellite contracts, then complete all with a single vehicle.

There is no rule that your satellite must *stay* in the selected orbit, or that it may not be re-used for another contract.

The only limitation is that it must be launched after accepting the contract.

A single 40000 launch can net almost a million in contract rewards.

Free money indeed.

[OscarJade]

Hallelujah. Completed one; about to complete another with the same satellite. Was obsessed with numbers instead of just eyeballing it :/ That said, MechJeb is great for maneuver execution (precision). I'm glad to barnstorm landings and docking by the seat of my pants, but MJ can have burn duration/execution. Sorry for above frustration!

[Axelord FTW]

Hallelujah. Completed one; about to complete another with the same satellite. Was obsessed with numbers instead of just eyeballing it :/ That said, MechJeb is great for maneuver execution (precision). I'm glad to barnstorm landings and docking by the seat of my pants, but MJ can have burn duration/execution. Sorry for above frustration!

Great to hear!

MJ is indeed very helpful for maneuver node completion and other menial tasks which can get tedious for the long time player.

I usually gather 4-5 satellite contracts, then complete all with a single vehicle.

There is no rule that your satellite must *stay* in the selected orbit, or that it may not be re-used for another contract.

The only limitation is that it must be launched after accepting the contract.

A single 40000 launch can net almost a million in contract rewards.

Free money indeed.

All of my launches usually also carry a probe (or four) with an appropriate set of antenna and dishes which is separated after the original orbital insertion (or latter, if providence permits) which is then hauled up to the right orbit. I get money off a satellite contract AND I get to set up an additional relay for RT satellite network.

[Pecan]

Congratulations

[Fenra24]

Turns out it was the direction I was *so* close though! it took forever to figure out the orbit! I'll have to relaunch the whole mission over again it seems...

[Pecan]

Turns out it was the direction I was *so* close though! it took forever to figure out the orbit! I'll have to relaunch the whole mission over again it seems...

Page 1, 1st reply, step 1: "Make sure you know which way around you're meant to go (follow the dots). A LOT of people don't."

[eddiew]

Hallelujah. Completed one; about to complete another with the same satellite. Was obsessed with numbers instead of just eyeballing it :/ That said, MechJeb is great for maneuver execution (precision). I'm glad to barnstorm landings and docking by the seat of my pants, but MJ can have burn duration/execution. Sorry for above frustration!

Yeah, the contracts tend to give too much information and bog you down in ideas about longitudes and latitudes - which aren't required, and which the game gives you no help with matching. Eyes and nodes are all you should need, although MJ is indeed nice for actually performing those burns with high accuracy. Or the long ones where you have time to go away and make tea