Molniya Orbits

[Jonfliesgoats]

I got my first contract to place a satellite into a Molniya orbit.  Is this a new contract or have I just missed them until now?  Also, how cool is it that KSP is actually getting us to experiment with practically useful orbits beyond geosynchronous and semi synchronous orbits?

[Allocthonous]

They showed up in 1.13 as well. Also featured: Polar orbits, Retrograde orbits, and Tundra orbits.

And I agree; I had to go look up the wikipedia page on Molniya and Tundra orbits to find out what the deal was. Cool stuff.

[Wjolcz]

Are they useful though? Apart from setting a comm link (which isn't actually that useful since it has occlusion moments when only KSC is enabled) there aren't many times you can actually use that probe for something meaningful.

It would be useful only if cameras and magnetometers were intoduced. Before that happens I will just avoid these tundra and molniya contracts because they aren't worth my time.

[Ripper2900]

For deepspace missions, it's usually a good thing to have a couple of highly elliptical, highly inclined com-relays.

They're almost never occluded , and for most of the time, they will be in ksp contact.

[Jonfliesgoats]

I think a science overhaul would greatly add depth to our spacefaring experience due to Veeltch's observation.  As is we only rarely need to get creative with our orbits.  

People are suggesting new sensors, new timeframes for experiments and new survey capabilities.  I think when we get more depth in space exploration and imaging, we will get incentives to be more ambitious.

imagine if we got science from observing aurora or polar weather on Jool?  We would find a way to get our sensors positioned for this.

[flatbear]

I got this contract back in the 1.1 days

[swjr-swis]

16 hours ago, Veeltch said:

Apart from setting a comm link (which isn't actually that useful since it has occlusion moments when only KSC is enabled) there aren't many times you can actually use that probe for something meaningful.

12 hours ago, Ripper2900 said:

They're almost never occluded , and for most of the time, they will be in ksp contact.

This is why Molniya orbits are usually populated by multiple satellites, at least triplets, so there's always at least one in the high/slow part of the orbit over the operational area. I don't think the stock contracts asking for these orbits do this though; at least, I've never seen it ask for more than one sat being placed in the same orbit.

The sort of application they tend to be used for, ground signal relay and observation specifically for high latitudes, does not really exist at the moment in stock. Except maybe in a very convoluted self-created situation of placing probe controlled vehicles in a deep valley on one of the far away planets. I agree it needs some more/other types of instruments to really have some practical use - even in the sense of the game.

 

[COL.R.Neville]

use these around the sun for pretty awesome system coverage with commnet. takes about 5 years to complete an orbit just remember radiators for the 600 million PE 

[Jonfliesgoats]

Good idea!  I don't have 1.2 in Xbox yet, but it's nice seeing more practical applications for creative orbiting.

[FancyMouse]

On 10/26/2016 at 5:04 AM, Veeltch said:

Are they useful though? Apart from setting a comm link (which isn't actually that useful since it has occlusion moments when only KSC is enabled) there aren't many times you can actually use that probe for something meaningful.

In a universe without planet oblateness, Molniya doesn't have advantage over other similar orbits with different inclinations. But IRL, stability of the orbit is a huge deal. If you read wiki, the sentence about "J2 term" is what I'm talking about. And if you will, you can argue Earth's Molniya orbit doesn't make sense to be Kerbin's Molniya orbit at all.

The lack of planet oblateness also makes Sun synchronous orbit impossible in KSP, which is something cool but missing in KSP (but I'm not worrying too much about this - there're already enough cool stuff for me to explore)

Back to KSP - probably polar orbit serves a better purpose when there's a need for coverage of high altitude area and/or less occlusion from planet.

Edited November 1, 2016 by FancyMouse

[samstarman5]

It would be interesting to see if oblation could be applied to the game. For one thing, as it is now, it really is totally unnecessary to have a launch complex at the equator except to have an easy launch to the Mun.  It costs the same to launch from the South Pole as it does from the KSC. Of course, I speak of taking the change of gravity into account with oblation, and not just the shape of the planets.  Changing how the planets are shaped is one thing, factoring in the differences in gravity is a whole other ball of kittens.

For those wondering, oblation is the world being flattened by its spin, kinda like what happens to an M&M when you squeeze it.  This causes gravity at the equator to actually be measurably less than at the poles.  It could be said the easiest way to lose weight is to move to Brazil.  This is why the ESA has about the best launch complex thus far in French Guiana. Now, you can't really see it with the Earth as it isn't spinning fast enough and it is a terrestrial world, but it is actually very apparent with Jupiter and Saturn. Moreso with Saturn, so just seeing photos of Saturn will help you fathom what's going on.

Unfortunately, right now anyway, that is as much lesson as I can provide. Why oblation plays a part in molniya orbits is something another more-read person would have to share.  Heck, I wouldn't be surprised if Scott Manley actually did a bit on it.  I will be reading on it myself, but I leave you with the opportunity to do so yourself.  As a wise man once said, "I could tell you, and you would be told. If I let you discover it, then you would know."  I'm rather fond of that saying.

Edited November 1, 2016 by samstarman5

[Akronnick]

Equatorial launch sites have greater rotational velocity than high latitudes, so there still is some advantage to an equatorial launch site.

Also you can launch directly into a 0° inclination orbit without doing a plane change burn.

Edited November 1, 2016 by Akronnick

[Kerbart]

15 minutes ago, samstarman5 said:

It would be interesting to see if oblation could be applied to the game. For one thing, as it is now, it really is totally unnecessary to have a launch complex at the equator except to have an easy launch to the Mun.  It costs the same to launch from the South Pole as it does from the KSC. Of course, I speak of taking the change of gravity into account with oblation, and not just the shape of the planets.  Changing how the planets are shaped is one thing, factoring in the differences in gravity is a whole other ball of kittens. (...)

I don't know, I'm pretty happy with the 175 m/s the KSC gets me for free for equatorial prograde orbits.

I'm pretty sure that's also the reason spaceports on Earth tend to be as close the equator as possible. The more you can get from that 465 m/s the better, especially as it drops of pretty rapidly with increasing latitude. That has a far, far bigger impact than the 0.07 m/s² benefit you get from a slightly lower gravity.

[Jonfliesgoats]

We do benefit from the sidereal velocity at the equator more than elsewhere, but oblate planets would be cool!  This said, perhaps I am missing something?  Wouldn't it be a relatively small change in the dimensions of planets to simulate this?  

[Kerbart]

4 hours ago, Jonfliesgoats said:

We do benefit from the sidereal velocity at the equator more than elsewhere, but oblate planets would be cool!  This said, perhaps I am missing something?  Wouldn't it be a relatively small change in the dimensions of planets to simulate this?  

Well, drawing the planets oblate would be a small change. Making the physics model adhere to it... Even the n-body mod treats the planets as point masses, as far as I know.

And imagine a polar orbit over an obloid spheroid. True orbital parameters are defined as distance from the center, but shown as distance from the surface (sealevel) of the planet. Wouldn't they be constantly changing as the effective radius of the planet changes with the latitude? There are a lot of things that rapidly get very complicated when doing so, I think.

[Jonfliesgoats]

I nod vigorously in an effort to comofluage my ignorance!  

i think a fair number of people would enjoy dabbling with the more nuanced physics.  whether or this is even achievable with the current software and consumer PC/consoles is another matter.

[wossname]

3 hours ago, Jonfliesgoats said:

I nod vigorously in an effort to comofluage my ignorance!

That may be the best sentence I have ever witnessed.