Contract deadlines vs. phase angles

[geb]

I'm quite curious about how this is going to work. For missions to LKO or Kerbin's moons, deadlines can cover a few days, and you'll probably have time to complete your plans (barring any screwups or navigational failure).

For interplanetary missions, it'll be a more interesting problem.

Are we going to have to carefully watch for departure windows and the planets aligning before we accept some of the more advanced contracts?

It would be nice if the contract system took this into account and offered contracts preferentially when a departure window was about to open. It would be a gentle prod in the right direction for anybody learning this stuff, without forcing anything on the veteran players.

[Bobbydylan]

I'm quite curious about how this is going to work. For missions to LKO or Kerbin's moons, deadlines can cover a few days, and you'll probably have time to complete your plans (barring any screwups or navigational failure).

For interplanetary missions, it'll be a more interesting problem.

Are we going to have to carefully watch for departure windows and the planets aligning before we accept some of the more advanced contracts?

It would be nice if the contract system took this into account and offered contracts preferentially when a departure window was about to open. It would be a gentle prod in the right direction for anybody learning this stuff, without forcing anything on the veteran players.

Hopefully those missions won't come up unless there's a window approaching.

[r4pt0r]

ive been interplanetary many times, i understand that certain launch windows can help you save fuel(but i always just launch whenever i want to launch), but what is a phase angle? the wiki page for that is gibberish to me.

[PlonioFludrasco]

Maybe interplanetary missions have a very long period on wich can be completed, long enough to allow you to wait for the next window.

Something longer than a synodic period, for example

[PlonioFludrasco]

ive been interplanetary many times, i understand that certain launch windows can help you save fuel(but i always just launch whenever i want to launch), but what is a phase angle? the wiki page for that is gibberish to me.

It's the angle between two planets, with the Sun as the center. For an optimal transfer, you must take care of that.

[r4pt0r]

oh like i imagine a clock with the sun in the middle and kerbin at the 6 oclock, you want to launch when duna is at the 4 oclock? i know that stuff sorta. at least thats how i do it.

[PlonioFludrasco]

oh like i imagine a clock with the sun in the middle and kerbin at the 6 oclock, you want to launch when duna is at the 4 oclock?

Yes, exactly, but a little more accurate XD

[Streetwind]

In the preview videos, even simple contracts like going to the Mun had huge deadlines of 4+ Kerbin years. It should be possible to find a halfways suitable transfer window in that kind of timeframe.

[qazsedcft]

You can technically launch at almost any phase angle; it just won't always be cost effective. So, you'll have to figure out when is the best time depending on your budget and the deadline. For instance, the most cost effective way might be to use low-thrust high-Isp engines but that might make you miss the deadline so you'll have to use something bigger.

[quantumpion]

I hope there are certain contracts with no time limit, otherwise fancy low-consumption tours which can take many years would be unfeasible.

[Bobbydylan]

I hope there are certain contracts with no time limit, otherwise fancy low-consumption tours which can take many years would be unfeasible.

Yeah, I think Voyager-esq grand tours would have very large time windows.

[Sky_walker]

If there are going to be any...

[Sma]

I hope there are certain contracts with no time limit, otherwise fancy low-consumption tours which can take many years would be unfeasible.

From what I've seen some of the deadlines are like 300days, or more. Maybe even 100+ years I don't remember lol.

I also wonder if you could place crafts around other planets, then accept a contract for say something around Duna and use the ship already there to do it and not have to worry about running out of time, or if you have to accept the contract before going there. Guess we'll find out Soonâ„¢

.

[Laie]

A good explainer re:Phase Angles is here: http://forum.kerbalspaceprogram.com/threads/53508-Manuever-nodes?p=707810&viewfull=1#post707810

And yes, the contract texts could well mention that the deadline has been set to correspond to the next launch window, wich will be "Y1, D234, +-12 days". They don't have to be gibberish, do they?

Edited July 17, 2014 by Laie
re:Phase was smileyfied

[ddenis]

Mmmm but what if it's a rescue mission and the one who we need to rescue is orbiting another planet with "life support" for a couple years just required to fly to him and return back... In that case I think It doesn't matter what phase angle is now...

[MiniMatt]

A good explainer re:Phase Angles is here: http://forum.kerbalspaceprogram.com/threads/53508-Manuever-nodes?p=707810&viewfull=1#post707810

And yes, the contract texts could well mention that the deadline has been set to correspond to the next launch window, wich will be will be "Y1, D234, +-12 days". They don't have do be gibberish, do they?

I've always thought that launch windows built into the calendar could be part of the discovery mechanism - ie. science not just producing new parts but greater understanding of orbital ballet. EG. get enough graviton sensor equipped satellites up and scientists begin to better understand and predict launch windows, adding additional functionality to the in-game calendar.

[Sma]

Mmmm but what if it's a rescue mission and the one who we need to rescue is orbiting another planet with "life support" for a couple years just required to fly to him and return back... In that case I think there is no matter what phase angle is now...

There is another thread somewhere discussing the matter of if you have the TAC lifesupport mode. One theory is/was that the way the spawning of kerbals work, the life support mode might not start working until you're in range of the kerbal anyway. Of course its just speculation for now. If you're using the old TAC mod that might not be the case, but once it's updated it may work out that way. Although a little unrealistic...lol.

Of course it may also not give you the option for that contract unless you have something in the vicinity anyway. Time will tell I guess...assuming we don't all go crazy from the wait. Or our SO's don't kill us from burning up the refresh button haha

[peadar1987]

Yeah, if you forget about aerobraking gains, eccentricity and inclination, you can basically launch at any time and just Exley Manoeuvre for an intercept for pretty much the same delta-V as waiting for a launch window.

[ddenis]

There is another thread somewhere discussing the matter of if you have the TAC lifesupport mode. One theory is/was that the way the spawning of kerbals work, the life support mode might not start working until you're in range of the kerbal anyway. Of course its just speculation for now. If you're using the old TAC mod that might not be the case, but once it's updated it may work out that way. Although a little unrealistic...lol.

Of course it may also not give you the option for that contract unless you have something in the vicinity anyway. Time will tell I guess...assuming we don't all go crazy from the wait. Or our SO's don't kill us from burning up the refresh button haha

I doesn't mean using TAC lifesupport mod or any other. It's "just pretend"... a story for myself, a situation where the time is more important than phase angle and efficiency of the rocket.

[Sma]

I doesn't mean using TAC lifesupport mod or any other. It's "just pretend"... a story for myself, a situation where the time is more important than phase angle and efficiency of the rocket.

Ahh gotchta. I could see that then.

Somewhat unrelated, but one time, maybe it was when I was playing the Demo Jeb got out of the command pod, and didn't know how to use his jetpack. By the time "he" figured out to turn it on he was too far from the pod to get back. So a rescue mission had to take place, but it was days later by the time they got there. He was a little upset at the lack of snacks for some reason lol.

I guess I never really thought about life support and just assumed that they were great at not having fresh air, water and food.

[qazsedcft]

I've always thought that launch windows built into the calendar could be part of the discovery mechanism - ie. science not just producing new parts but greater understanding of orbital ballet. EG. get enough graviton sensor equipped satellites up and scientists begin to better understand and predict launch windows, adding additional functionality to the in-game calendar.

I disagree. That stuff has been well understood since the 17th century so well before the space age. Well, technically there were still a few issues that needed General Relativity to work out but that was still before the space age.

[MiniMatt]

I disagree. That stuff has been well understood since the 17th century so well before the space age. Well, technically there were still a few issues that needed General Relativity to work out but that was still before the space age.

Yeah, but ladders have been understood since well before that - yet Kerbals invent Mun-worthy rockets before ladders Real life doesn't exactly map to KSP

Similar argument could made against having planetary body discovery, in that we've known about all the planets & moons, asteroid belts, and even the odd dwarf planet for ages. Yet if it would make a fun game mechanic then putting it in is a no-brainer.

[qazsedcft]

I see the KSP "science" more as engineering and R&D than real science. So they are solving engineering problems to make some new parts useable in practice. But yeah, I understand your point and I don't expect it to be fully realistic.

[RoboRay]

Hopefully those missions won't come up unless there's a window approaching.

I really hope they do.

It's possible to make transfers at less-opportune times, but it's more challenging to build and loft a vessel that can do it. A quickly-expiring contract that offers a big payout for managing to accomplish a transfer outside the Hohmann window would be very interesting.

Note that a non-Hohmann transfer is also going to get you there faster. There are good reasons to use other than the minimum-energy option.

Edited July 17, 2014 by RoboRay

[Sandworm]

Isn't it strange how we insist on the realism of launch windows on one hand but are totally dismissive of the ladders-after-rockets paradox on the other?

It looks like the stock contracts have a default time multiplier based on which body you are headed to. Anything beyond kerbin gets years and years. I don't think KSP calculates launch windows anywhere and I'm kinda glad it doesn't. The various mods that do (protractor, VOID, mechjeb, KER etc) often disagree with each other. I'd hate for an adopted stock calculation to become a default where clearly opinions may differ.