Contract specifics

[TinfoilChef]

Looking through the contracts I ran into some that ask for a new satellite to be launched into a specific orbit.

The good part is that the contract specifies the orbital parameters

(from an actual contract offer)

Objective:

Please note that this must be a new unmanned probe built for the agency after the contract is accepted.

Apoapsis: 7,192,125 meters

Periapsis: 5,310,959 meters

Inclination: 0 degrees

Longitude of Acending Node: Undefined

Argument of periapsis: 288.3 degrees

It also states that I need to "reach designated equatorial orbit around Kerbin within reasonable deviation.

My questions:

What is considered a "reasonable deviation"?

Wouldn't it make more sense to list orbital altitudes in KM?

If I'm expected to match orbit parameters within meters, then somebody is clearly insane.

That is simply NOT going to happen.

What in Finagle's name is "argument of periapsis" and how am I supposed to know what this is in stock KSP?

In flight, especially in early tech levels when just reaching orbit is a flogging miracle, I am NOT going to attempt calculating this or any other value on the fly when it's not shown on the HUD

[shand]

i'm unsure if this has been implimented in Beta Than Ever, but in contracts+ where the new contract system came from it shows the orbit in your map view. so just match that as close as you can.

reasonable is around 5% on each argument.

[biohazard15]

Yeah, these "match designated orbit" contracts from Fine Print can be hard. Just wait until you'll get an "orbit around the Sun" contract - it could be even harder in dV terms than Moho.

And yes, go to the map, target the body specified (Kerbin, in that instance) and you'll see the orbit.

[TinfoilChef]

Ok. so far so good.

yet still there's no explanation of what "argument of periapsis" is and since it's now being given as a requirement for contracts in vanilla, shouldn't the vanilla game also explain ... it is and show how to measure it?

I refuse to believe that Squad expects players to tab out of the game and google it

[SpaceCars]

The argument of periapsis is a numerical way of telling where in the orbit the periapsis is. So it is shown in-game in the map view. If you rotate your orbit (e.g. by burning radially, toward the blue markers) you see the periapsis and apoapsis shifting. Thus you can just visually line up your apoapsis with the required apoapsis in map view to complete the contract. Note that the margin is quite large enough that you can fulfill the contract by eyeballing it without having to resort to any read-outs.

[TinfoilChef]

The argument of periapsis is a numerical way of telling where in the orbit the periapsis is. So it is shown in-game in the map view. If you rotate your orbit (e.g. by burning radially, toward the blue markers) you see the periapsis and apoapsis shifting. Thus you can just visually line up your apoapsis with the required apoapsis in map view to complete the contract. Note that the margin is quite large enough that you can fulfill the contract by eyeballing it without having to resort to any read-outs.

Somehow I doubt new players are going to know this and frankly, I would prefer to have numeric readouts... for all the things. It's one of the main reasons I use MJ's custom window functions. That and Smart A.S.S.

[Superfluous J]

Personally I think the orbit specifics should not have any of those terms or numbers. The entire thing should be:

"Launch a satellite into an orbit close to the purple one around Kerbin in the tracking station."

[The_Rocketeer]

For what possible reason would any 'Kerbal agency' want a satellite in a highly eccentric orbit? Surely this contract should just be a case of circular orbit at x altitude and y inclination?

0.9 is rapidly putting me off career. I'd hoped it would be so much more fun...

[SpaceCars]

That is actually quite realistic. To get good coverage at high latitude, such orbits have been used for communication or television satellites in real life: e.g. see the Molnya orbit or the Tundra orbit. Further, what about a spy satellite which you want to pass over a specific site? Or a mapping satellite, which you could best place in a Polar orbit?

Other than that, it gives a good challenge for new players to learn about inclination.

[RainDreamer]

Also remember, this is kerbals we are talking about. Common sense has not been one of their strong point.

[Janos1986]

I really hope there is a bit of a tolerance threshold for those missions.

[Claw]

There is a tolerance. I don't know the exact number, but I will see if I can find out...

Argument of PE is PE. That's just the long name for it. And AP/PE has been visible in this game for quite some time. I get your point if you haven't seen the phrase "argument of PE" before, but now you know.

Cheers,

-Claw

[WanderingKid]

The vig on the orbit is pretty reasonable, actually. I've put up a few (more with Fine Print in previous version) and it's rather generous with how off you can be. The size of the orbits though can be pretty huge. I've got two requested at the moment that lie between Mun and Minmus, and recently dropped off one that will, at some point, have the Mun either eat it or send it off into nowhere. Anywhere in SOI is legal for it, I suppose.

As to new players, I don't think it's quite that bad. While the terms may be dizzying, the on screen eyeball of the orbit is simple enough, once they've learned how to orbit. Until then they're not sending up satellites anyway.

[TinfoilChef]

There is a tolerance. I don't know the exact number, but I will see if I can find out...

Argument of PE is PE. That's just the long name for it. And AP/PE has been visible in this game for quite some time. I get your point if you haven't seen the phrase "argument of PE" before, but now you know.

Cheers,

-Claw

I'm thinking that it's got to be different, else why would "argument of periapsis" be included when AP and PE are already listed?

Sounds like SpaceCars comment above is probably it, the location in the orbit where the PE is supposed to be, in the example I quoted, 288.3 degrees.

This begs the next obvious question; 288.3 degrees from what? Without a reference point such a number is meaningless.

[DevonKiwi]

Sorry to but in on this thread, but I'm also struggling with someting very similar. I have a contract to place a probe in a specific orbit around the Mun. Here is whre I've got to. http://1drv.ms/1xsCLl1 (I hope that works!). As far as I can see, my orbit is as close as I can reasonably be expexted to reach. ... am I missing?

[zarakon]

Personally I think the orbit specifics should not have any of those terms or numbers. The entire thing should be:

"Launch a satellite into an orbit close to the purple one around Kerbin in the tracking station."

Yeah, what it really needs is a "View on map" button in the contract description

[zarakon]

Sorry to but in on this thread, but I'm also struggling with someting very similar. I have a contract to place a probe in a specific orbit around the Mun. Here is whre I've got to. http://1drv.ms/1xsCLl1 (I hope that works!). As far as I can see, my orbit is as close as I can reasonably be expexted to reach. ... am I missing?

Make sure you're going the right direction. If that's not the problem, then I dunno

[TriggerAu]

There is a tolerance. I don't know the exact number, but I will see if I can find out...

Argument of PE is PE. That's just the long name for it. And AP/PE has been visible in this game for quite some time. I get your point if you haven't seen the phrase "argument of PE" before, but now you know.

Cheers,

-Claw

Just need to correct this - sorry Claw. The Argument of Periapsis is how far around the orbital plane the Pe point occurs. Its one of 6 variables that define an orbit, and the most easy to read explanation I can think of is this one - http://en.wikipedia.org/wiki/Orbital_elements.

On the main topic, I can see and understand the point of that measurement being a bit cryptic for people who dont know. I'm sure Arsonide would love the feedback.

[DevonKiwi]

Thanks. That was it!

[Pecan]

Somehow I doubt new players are going to know this and frankly, I would prefer to have numeric readouts... for all the things. It's one of the main reasons I use MJ's custom window functions. That and Smart A.S.S.

Career mode is emphatically NOT a way into KSP for new players. Meanwhile, more than 80% said we wanted a dV display in a forum poll this year - can't have too much information ^^.

[prospeckt]

Hey I actually was able to finish all the contract specifications, but the "new unmanned probe" requirement is not being fulfilled. I made the probe from scratch and named it too, any idea where I went wrong or is this a bug?

[Newman]

Hey all, long time KSP player here (started out before we had the Mun, since then played several playthroughs, exploring everything that can be explored while successfully bringing my guys back alive each time (thanks in large part to the quicksave option)..

Anyway, I consider myself to be pretty experienced when it comes to handling KSP; if it's possible to do with stock, chances are I did it.

So I just tried to fulfill a contract that requires me to launch an unmanned probe that has power and an antenna, into specific orbital parameters withing "reasonable deviation". Not sure what reasonable is, but with my fledgling new space program (don't have RCS yet) it took quite a lot of fiddling to match the orbit to the one drawn in map view visually exactly (numbers wise it's all within a few hundred m, considering apoapsis is over 14,000,000 m that's pretty exact). And yes, I did match the apoapsis and periapsis point positions to the ones drawn on map, though I don't really think that should be a requirement, if I'm honest.

Game's still not recognizing I did this. I literally dare not touch the orbit at all anymore since even using the reaction wheels seems to whack out the numbers in map view, and any modification I do now just gets it further away from specified parameters. Is this a bug or is "reasonable deviation" considered to be precision within a meter?

If the latter, I'd like to point out several things:

- you get satellite contracts fairly early in the game, as it should be. However, that early we don't really have all the bells and whistles, RCS included.

- numbers in map view still go crazy when you steer the craft, even without engines and RCS, just using reaction wheels. I just had a situation where my orbit was about 2km too high, so at periapsis I turned the craft retrograde to drop the apoapsis for 2km. However turned retrogade the map view decided my apoapsis was now 2km too low! Turning the craft back, it was again 2km too high. You get the problem - with this kind of supersensitivity insisting on crazy precision is a bad idea.

- there's literally no reason to insist on crazy precision as long as the satellite is roughly in a specified orbit. In fact I'd just draw a whole zone it needs to be in in map view. If you want it's apoapsis to be 14,124.000 m or some such number than anything between 14,000.000 and say, 14,200.000 should be considered reasonable deviation.

- when specifying target orbits, do try to avoid ones that take your probe into the gravitational sphere of influence of another body, such as the Mun. Fiddling your orbit to perfection for hours only to have the Mun get a bit too close and pull the probe in is just plain annoying.

Why? Because fiddling with orbital parameters for hours while the game still considers it "not good enough" simply isn't fun. I was looking forward to satellite contracts, but now that they're in there I find they're laborious, boring, and don't make much sense (lots of these orbital parameters would make no sense for a commercial satellite). Instead of fiddling for hours on end for no good reason, we could be exploring moons and planets. I realize this is still beta, and I'm hoping this feedback will be helpful for future updates.

Oh, quick thought while I'm at it, I think a camera part should be added, allowing us to take shots of other planet surfaces from probes. That could be good contract requirements as well - take and transmit shots of duna polar region, etc.

Edited January 24, 2015 by Newman

[Superfluous J]

So I just tried to fulfill a contract that requires me to launch an unmanned probe that has power and an antenna, into specific orbital parameters withing "reasonable deviation". Not sure what reasonable is, but with my fledgling new space program (don't have RCS yet) it took quite a lot of fiddling to match the orbit to the one drawn in map view visually exactly (numbers wise it's all within a few hundred m, considering apoapsis is over 14,000,000 m that's pretty exact). And yes, I did match the apoapsis and periapsis point positions to the ones drawn on map, though I don't really think that should be a requirement, if I'm honest.

It's not. I ignore all the markers except maybe the AN/DN to make sure I'm within a few degrees.

Game's still not recognizing I did this. I literally dare not touch the orbit at all anymore since even using the reaction wheels seems to whack out the numbers in map view, and any modification I do now just gets it further away from specified parameters. Is this a bug or is "reasonable deviation" considered to be precision within a meter?

It's very likely neither.

I would be willing to wager a dollar that if you check your AN or DN they say "180" (or close) instead of "0" (or close). i.e., your orbit is perfectly set up except it's backwards. You don't even need to check the AN/DN, just look at the little dots on the target orbit and see which way they're going.

[Newman]

It's not. I ignore all the markers except maybe the AN/DN to make sure I'm within a few degrees.

It's very likely neither.

I would be willing to wager a dollar that if you check your AN or DN they say "180" (or close) instead of "0" (or close). i.e., your orbit is perfectly set up except it's backwards. You don't even need to check the AN/DN, just look at the little dots on the target orbit and see which way they're going.

Thanks for the reply. Unfortunately I canned the flight and canceled the contract after a near pass of the Mun completely destroyed all the work put into it, so I can't check anymore. I suppose it's possible the contract was for a retrograde orbit, though I thought it wasn't.

[KSK]

It's not. I ignore all the markers except maybe the AN/DN to make sure I'm within a few degrees.

Interesting - I do it the other way round. Get into a circular parking orbit, set up a prograde burn such that my predicted apoapsis matches the required apoapsis marker by eye, doing a quick radial burn midway to correct my apoapsis point if required. Burn at apoapsis to match my periapsis to the marker, tweak inclination as required.