NASA Discovers 'Motorway' Network Between Planets

Ananova ^ | 7-18-2002

[blam]

Nasa discovers 'motorway' network between planets

Nasa says an interplanetary superhighway discovered by one of its engineers will make space travel simpler.

The solar system 'motorway' is a virtual network of winding tunnels and channels around the Sun and planets.

Each planet and moon has five locations in space called Lagrange points, where one body's gravity balances another. Spacecraft can orbit at those points while burning little fuel.

He came up with the superhighway by mapping out all the possible flight paths among the Lagrange points to see how fast or slow the spacecraft would travel.

Experts say the superhighway flight path will drastically cut the amount of fuel needed for future missions.

Nasa hopes to use the system for future human space missions by building spacecraft docking and repair platforms around the Lagrange points.

The system was discovered by Nasa Jet Propulsion Laboratory engineer Martin Lo.

He's using the theory to draw up a flight path for the Genesis Sun probe and plans to map out a superhighway for the entire solar system.

Mr Lo told the Nasa website: "Designing the Genesis spacecraft's flight path with traditional methods used to take eight weeks - now we design a new flight path in less than a day.

"The savings on fuel translates into a better and cheaper mission."

Story filed: 11:30 Thursday 18th July 2002

[TeleStraightShooter]

From #78:
You are right that the L4 and L5 points are "wells", the L1 through L3 points are "peaks".

How about this for a compromise:
Since I have #28, I'll claim the L4 & L5's
VadeRetro has #79 so he gets the L1 & L3's
you can have the L2's.......

Fair enough?

[Lazamataz]

Nope. VadeRetro beat us fair and square.

[El Gato]

if an object reaches that point, why won't it just continue on it's trajectory? there's no opposing force to bring it to a stop, like retrojets on a craft. am i missing something?

Two of the points are stable, that is things in there tend to stay in there because the net gravitry force from the two large objects tends to pull them back towards the Lagrange point if they move away from it. Of course if they are moving fast enough, they get out that stable region before the graviational forces can pull them back into it. The other L points are not stable in that way, IIRC. The stable ones are the ones which trail and lead the smaller body in it's orbit around the larger one.

[TC Rider]

Look for "Footfall" written in the early-mid 80s.

LOL, I saw some science 'fact' article the other day about powering a spaceship with nuclear bombs. Imagine that.

< /irony >

[Doc On The Bay]

Both Niven & Pournelle have Written EXCELLENT SF!!

WELL WORTH READING!!

GO for IT!!!

Doc

[TC Rider]

Both Niven & Pournelle have Written EXCELLENT SF!!

I agree with that statement but would advise Freepers who might enjoy their science fiction to avoid their non-fiction.

Pournelle has me POd everytime I read his articles.

[Oztrich Boy]

I read Niven/Pournelle's Lucifer's Hammer. Great book. Have they written anything since?

Quite a lot, just from my library

Inferno
Footfall
Oath of Fealty
The Mote in God's Eye and The Gripping Hand (aka the Moat around Murchinson's Eye) - from whence the Alderson points

[altair]

On the gripping hand ... a Niven and Pournelle bump.

[Aarchaeus]

"I thought they outlawed hitch hiking."

But aparently it might still be an option. This seems to be a "Hitchhiker's Guide to the Solar System".

[altair]

Yes, it is well worth reading. "It's probably the finest story ever written about alien invasion."

[Don Joe]

"This should be post 78 or thereabouts. I hope this settles this acrimonious and unseemly dispute. (Maybe I'd better up my guess to 79.)"

Guessing posts again? I wonder if you can still reply to posts that haven't been posted yet?

[Don Joe]

I guess not.

[longshadow]

BTW, aren't those Lagrange points full of meteors and such?

I shouldn't think so; now, this is conjecture on my part, and I'll assume RA or some other knowledgeable FReeper will correct me if I'm mistaken, but I assume that the Lagrange points are unstable, in the sense that any minor displacement away from the EXACT point of gravitational balance results in an ever greater gravitational displacement force on an object, NOT a restoring force. IOW, it's like a "saddle" point: there is an equilibrium, but it's dynamically unstable. Any pertubation will cause the object to drift away unless something actively counter-acts the displacement. Hence, I would conclude there shouldn't be much space debris floating about at the Lagrange points.....

[RightWhale]

the 60 degree thing.

It's a matter of proportion not scale. The moon has such points, as does earth. L4 and L5 are 60 degrees as seen from the point at the center of the orbit.

[SamAdams76]

Just watch out for those speed traps between Neptune and Saturn.

[VadeRetro]

Read on. You're right about three, wrong about two.

[altair]

from whence the Alderson points

Dan Alderson is a scientist at JPL, by the way.

[RightWhale]

Consider yourself surprised. L1, L2, and L3 are as you described, gravity peaks, but with zero slope at the center. L4 and L5 are gravity wells.

[PatrickHenry]

From the lead article:
Each planet and moon has five locations in space called Lagrange points, where one body's gravity balances another. Spacecraft can orbit at those points while burning little fuel.

How much fuel does it take to travel in an orbit? I assume this is yet another example of idiotic journalism. Also, Lagrange points are not a new topic. A Google search will give you several "L5 Society" pages.