Space lanes?

[Nich]

A couple years ago I read about "space lanes" or "space highways" where you basically use n body physics to transfer from body to body.  I think it was something about using the L1 lagrange point you could transfer and capture at the moon for less dv then the transfer burn required by 2 body physics.  The disadvantages were they they were very slow (7-12 day transfer to the moon I think).  In the example I saw they transferred into a high moon orbit because that is very expensive from a 2 body perspective for less total dv then a minimum homan transfer to low PE (3142ish).  However depending how you hit the L1 point I dont see why transfer to a low PE would be possible and I think you would have less hyperbolic velocity. However the dv savings are small, like 10-15 on transfer and 30-40 on capture from LEO to LLO.

Has anyone heard of these before and know the proper name?  I wanted to do some research on how these could be used for transfer to mars.

Edited May 29, 2019 by Nich

[Martian Emigrant]

Hi @Nich

Not sure about the Lagrange points. But do you mean the Mars cycler?

https://en.wikipedia.org/wiki/Mars_cycler

It works for other bodies as well.

 

I remember reading about...(So vague now)....a moon probe maybe Japanese that was in the wrong orbit with not enough delta-V.

They consulted a math-physic-guy who figured how to ride the ridge of gravitational wells.

The probe was sent to hover between the earth and the sun and the moon before falling on the moon side with fuel to spare....

 

As I type this I researched it and it was the Hiten probe.

https://en.wikipedia.org/wiki/Hiten

I think you mean a "Ballistic capture" or "low energy transfer". Apparently developed by Edward Belbruno and James Miller of the Jet Propulsion Laboratory

 

Edited May 29, 2019 by Martian Emigrant

[Richy teh space man]

You mean this? https://en.wikipedia.org/wiki/Interplanetary_Transport_Network

Afaik it wouldn't work in KSP since KSP doens't have n body physics, or lagrange points..

[Opus_723]

15 minutes ago, Richy teh space man said:

You mean this? https://en.wikipedia.org/wiki/Interplanetary_Transport_Network

Afaik it wouldn't work in KSP since KSP doens't have n body physics, or lagrange points..

It would be pretty cool if they just added the major stable Lagrange points (Kerbin-Mun, Jool-Kerbol) to the solar system as orbitable spheres of influence in the current patched conic system. Then we could park asteroids and stations around them.

Edited May 29, 2019 by Opus_723

[cantab]

52 minutes ago, Opus_723 said:

It would be pretty cool if they just added the major stable Lagrange points (Kerbin-Mun, Jool-Kerbol) to the solar system as orbitable spheres of influence in the current patched conic system. Then we could park asteroids and stations around them.

Unfortunately Lagrange points don't work that way, so they can't be realistically simulated by the point masses that KSP uses.

[Nich]

@Opus_723 I have not played with Kentipia (i believe) but it should have all the Lagrange points as they are not really a thing they are just the result of taking account of all the gravity's at once.

@Richy teh space man That was the exact article I was thinking of.

This got me thinking what would a transfer to the moon look like if you locked the reference frame to the earth and the moon.  I am thinking something like this.

After thinking about it probably more like this

Wish I remembered my frame reference math from physics

Edited May 29, 2019 by Nich

[Vanamonde]

Thread moved to Science & Spaceflight, since it's not about KSP flight. 

[FleshJeb]

43 minutes ago, Nich said:

Kentipia

Principia, but good guess!

 

[Opus_723]

1 hour ago, cantab said:

Unfortunately Lagrange points don't work that way, so they can't be realistically simulated by the point masses that KSP uses.

I know the force law is different than for a point mass, but it shouldn't be too crazy to add a "Hookean" sphere of influence, unless the code is a lot more spaghettified than I'm assuming.

[wumpus]

15 hours ago, Opus_723 said:

I know the force law is different than for a point mass, but it shouldn't be too crazy to add a "Hookean" sphere of influence, unless the code is a lot more spaghettified than I'm assuming.

There should probably be some sort of computer science law that states that the code is always more speghettified than you think, especially if the code is written in a language that allows object orientation.

[Nich]

There are lots of problems.  First is the L4 and L5 points have inverse gravity.  The gravity gets stronger the further from the center you are.  This might be doable but would require a custom physics engine most likely.  The L1, L2 and L3 points would require something like a pringle gravity field.  I am guessing the main problem with Principia is multiple crafts in orbit the game crawls to a standstill.  You could do a reduced SOI where anything in a rather low orbit around a body gets 2 body and after say GEOish altitude the game switches to N body.

Edited May 30, 2019 by Nich