Munar Polar Orbit - Why is it not Polar? ~Answered~

[MrOsterman]

First I'm not running mods and I'd like to not run mods.  Just sayin'.

Here's my problem.  I've got a satellite in munar orbit.  It's got an orbital survey scanner attached (it was actually part of a contract) and I've tried to push it into a north/south orbit around the mun.  I'm 90% sure I've got it as up/down as I can get it, but when I attempt to do a munar scan I keep getting the message of "you must be blah blah blah".  I'm also orbiting at an average altitude of 86k above the mun's surface in a near circle.

What am I missing?  Is there a way in the stock game to verify what my angle of orientation is for this orbit?

Edited December 4, 2015 by MrOsterman

[Chaos_Klaus]

screenshot maybe?

[Kobymaru]

Quote

What am I missing?  Is there a way in the stock game to verify what my angle of orientation is for this orbit?

The best way to check if you are "very polar" is how fast the navball flips its direction when you pass over the poles. If very fast, you are very polar. If not, you are not. I think that's about as precise as it's gonna get in stock. If you want numbers, you need either MechJeb or Kerbal Engineer Redux.

 

40 minutes ago, MrOsterman said:

First I'm not running mods and I'd like to not run mods.  Just sayin'.

Here's my problem.  I've got a satellite in munar orbit.  It's got an orbital survey scanner attached (it was actually part of a contract) and I've tried to push it into a north/south orbit around the mun.  I'm 90% sure I've got it as up/down as I can get it, but when I attempt to do a munar scan I keep getting the message of "you must be blah blah blah".  I'm also orbiting at an average altitude of 86k above the mun's surface in a near circle.

If you are in the right altitude and you are in the correct orbit (please post a pic), it's probably a bug. The ressource scanning has been buggy in 1.0.5, I've read that your thing happens sometimes.

Does the problem persist if you resart the game?

 

Edited December 3, 2015 by Kobymaru

[MrOsterman]

I'll have to look when I get home tonight; I'm at work.

 

I've been trying to avoid mods that add too much functionality because I don't want my game play to be reliant on the mods working to keep me playing and I don't want to be unable to play if my mods break.

[Snark]

1 hour ago, MrOsterman said:

I'll have to look when I get home tonight; I'm at work.

 

I've been trying to avoid mods that add too much functionality because I don't want my game play to be reliant on the mods working to keep me playing and I don't want to be unable to play if my mods break.

Do you have an antenna on your probe?  It won't let you do the scan without an antenna.

Yah, I'm with you.  I run some mods, yes, but ones that either make the game harder (like RemoteTech) or add new content (like Outer Planets).  Nothing that provides lots of assistance (like MechJeb or KER), because they'd take the fun out of the game for me-- I like solving those problems myself. 

For what it's worth:  I've had no problems with resource scanning.  If I eyeball an orbit and it looks polar to me, the scanner does the scan.  It doesn't seem to be super-finicky about the inclination, I think as long as it's within a few degrees of perfectly polar then it's fine.  When I try to do a scan and it says "you must be blah blah blah", the problem always turns out to be that either my periapsis is too low or my apoapsis is too high, and then I just adjust it and it's good to go.

Or else I forgot the gosh-darn antenna. 

Edited December 3, 2015 by Snark

[MrOsterman]

I've got a satellite dish on the top of it, an extendable solar panel going off one side and the scanner on the other.  It's possible I don't have enough charge to run the scanner but I've got this massive battery on there too.

Hmm... maybe I'll just eat the 50k and try sending up a new probe.

[Snark]

10 minutes ago, MrOsterman said:

I've got a satellite dish on the top of it, an extendable solar panel going off one side and the scanner on the other.  It's possible I don't have enough charge to run the scanner but I've got this massive battery on there too.

Hmm... maybe I'll just eat the 50k and try sending up a new probe.

What exactly is the error message that it's giving you?  (Not just "You must be blah blah blah.") 

Also, a pic of the probe might help.

[Aethon]

https://youtu.be/_akwHYMdbsM?t=20

Edited December 3, 2015 by Aethon

[Tex_NL]

30 minutes ago, MrOsterman said:

I've got a satellite dish on the top of it, an extendable solar panel going off one side and the scanner on the other.  It's possible I don't have enough charge to run the scanner but I've got this massive battery on there too.

Hmm... maybe I'll just eat the 50k and try sending up a new probe.

Keep in mind the survey scanner is NOT a comm dish.
And you might be using the wrong survey scanner. The big dish is for orbital scanning, the small rotating hexagon for low altitude scanning with high detail. But that one won't help you unless you've surveyed from orbit first.

Besides that I have to agree with Klaus and Snark: To further diagnose your illness problem we'll need to see the patient satellite.

[Pronoes]

42 minutes ago, Snark said:

 Nothing that provides lots of assistance (like MechJeb or KER), because they'd take the fun out of the game for me-- I like solving those problems myself. 

I'd just like to point out KER doesn't provide assistance. It merely gives you a lot of information otherwise unavailable or difficult to find in game. Mechjeb can be used to autopilot and auto dock and auto do pretty much anything, but KER simply gives info.

[MrOsterman]

Okay, I'll screen grab when I get home and check that error at the same time.  I'm 95% sure that I have the Orbital Scanner on the satellite because it was a requirement of a contract to do the usual "have a satellite that can communicate and has a way generate power".  Oddly the requested orbit wasn't a polar one.

 

I'll look too at the Engineer Mod and see if that doesn't give me too much information beyond vanilla.

Thanks so far guys (girls).

[Batmanpuncher]

Your best bet is to use Kerbal engineer, it adds no parts (except for the ship computer) and the version of the game doesn't really effect its function (you could use the 1.0.4 version on 1.0.5) so you don't need to worry about it breaking or it breaking your ships. Could also just be a bug.

 

hope that helps

 

Edited December 3, 2015 by Batmanpuncher

[Yakky]

4 hours ago, Aethon said:

https://youtu.be/_akwHYMdbsM?t=20

In case Aethon's post was not clear enough... are you orbiting in the right direction?  You could be 180 degrees off and still "polar"...

 

 

[Snark]

4 hours ago, Yakky said:

In case Aethon's post was not clear enough... are you orbiting in the right direction?  You could be 180 degrees off and still "polar"...

I don't think he's trying to match a particular orbit for satisfying a contract-- he's just trying to get the ore scanner to work.  So the old "oops, I'm orbiting in the wrong direction" shtick doesn't apply here, I think.

[Snark]

8 hours ago, Pronoes said:

I'd just like to point out KER doesn't provide assistance. It merely gives you a lot of information otherwise unavailable or difficult to find in game. Mechjeb can be used to autopilot and auto dock and auto do pretty much anything, but KER simply gives info.

Sure it provides assistance.  Very valuable assistance.  That's why it's such an immensely popular mod.    The assistance happens to be in the form of information, rather than active autopiloting as MechJeb does, but that doesn't make it any less of a help.

And I'm glad that such a mod exists, it's hugely useful to lots of people for whom calculating that stuff manually would be tedious or difficult.  It just happens to be that I myself choose not to use it, for the same reason that I don't use MechJeb:  it would suck a lot of enjoyment out of the game.  I like pulling out my calculator and doing Tsiolkovsky calculations when I'm building a rocket.  I don't want a mod to take that away from me.

(Not that I'm completely obsessive, though.  Some things are just dumb.  Couldn't stand the flaky, unreliable "estimated burn time" indicator, and the repeated manual calculation was tedious, so I wrote a mod to fix it.  But that's about as far as I'm willing to go.)

[Damien_The_Unbeliever]

One way to check whether your orbit is polar - turn on the "Biomes visible in map view" option in the Debug (F12) menu. The polar biomes on the Mun are circular. If you focus on Mun and rotate the map view until your orbit is a straight line, you'll be able to assess how polar your orbit is by how close to the centre of the circle your orbit gets.

Edited December 4, 2015 by Damien_The_Unbeliever
minor typo

[MrOsterman]

Good News!  It was the altitude.  For some reason I didn't catch that my Ap was at 105k rather than less than 100 so a short retro burn and BANG I was able to scan the moon.

Next phase is to actually rescue some one off of it.  My last effort ended up with a stranded return vessel (burned a LOT of fuel trying to get to the right landing site) which I reverted, only to try again, miss the landing site, and then strand my rescue team in a HKO trying to get home.

So to recap, I've scanned the mun but I've got a stranded Kerbalnaut hanging out on the surface waiting a ride home, and two more in a HKO waiting someone to bring them more fuel.

Greeeeaaaattttt.....

[Snark]

3 hours ago, MrOsterman said:

So to recap, I've scanned the mun but I've got a stranded Kerbalnaut hanging out on the surface waiting a ride home, and two more in a HKO waiting someone to bring them more fuel.

Greeeeaaaattttt.....

By the way, one option to consider when rescuing your kerbalnauts stranded in HKO:  They can go EVA and lower their orbit by a lot just by using their EVA thrusters.  Those EVA thrusters pack a ridiculous amount of dV, something over 300 m/s.  You can lower them into an orbit that's much cheaper for your rescue ship to get to. Go on EVA, then retro-burn at Ap to lower your Pe as far as you can without hitting atmosphere.  Then, if you have any dV left, spend it to retro-burn at Pe to lower your Ap as far as you can.  Leave yourself a smidgeon of EVA propellant for doing some maneuvering when your rescue ship meets them-- a kerbal in orbit with zero EVA fuel left is surprisingly awkward to rescue.

Then all you need to do is send up a cheap, light ship with enough empty crew slots for your kerbals to come aboard.  The rescue ship only needs to pack enough dV to get into the low orbit.

(The one drawback to this, if you have kerbals, plural, is that they'll end up scattered around when they go EVA, so your rescue operation will involve a certain amount of tedium rounding them up.)

As for rescuing your kerbal who's stranded on the Mun:  Bear in mind that you don't need a pinpoint landing.  As long as you get within a few kilometers, the stranded kerbal can fly on EVA to the rescue ship after landing.  It's not like Minmus, where a kerbal on the surface can actually get to orbit (and even escape Minmus and head home) using only EVA propellant... but you have plenty to fly for dozens of kilometers.

Is your stranded kerbal close to the Mun's equator, or somewhere at high latitude?

And are you familiar with "suicide burn" techniques for efficient Mun landings?

[MrOsterman]

On 12/4/2015, 11:10:36, Snark said:

 

And are you familiar with "suicide burn" techniques for efficient Mun landings?

I think so....

I just did a Mun landing by pointing myself DIRECTLY at my landing point and then burning full Retro (relative to the surface) once I was close enough to come to a nice slow descent.  Totally skipped the whole "get an orbit going" portion of my approach.  I'm not sure I'm a TOTAL fan of the method yet but I plan to use it later to recover that lost Kerbal for the contract.

[Snark]

2 hours ago, MrOsterman said:

I think so....

I just did a Mun landing by pointing myself DIRECTLY at my landing point and then burning full Retro (relative to the surface) once I was close enough to come to a nice slow descent.  Totally skipped the whole "get an orbit going" portion of my approach.  I'm not sure I'm a TOTAL fan of the method yet but I plan to use it later to recover that lost Kerbal for the contract.

That's not quite what "suicide burn" means.  A suicide burn is based on the principle that a "nice slow descent" is really bad, because it wastes a lot of fuel.

A "suicide burn" consists of the following:

1. Be on a trajectory that impacts the surface
2. Free fall.  Wait, and wait, and wait.
3. At the absolute last possible instant, slam on full throttle.
4. Your velocity reaches zero right when you arrive on the surface.  Cut throttle.

Basically, an optimal suicide-burn landing looks like this:  take a movie of a landed ship blasting off at full thrust, and play it backwards.

Judging exactly when the "last possible instant" is, is tricky.  Do it too early, and you waste fuel.  Do it too late, and you discover why it's called a suicide burn. 

There are some games you can play with maneuver nodes to help you judge when that "last possible instant" is.