Track Of light

KerrTexas

KerrTexas

Super Moderator
I was scanning through a spacecraft art gallery and one picture that got me to thinking...
We have trains that use magnetic track systems for propulsion. What steps or designs would be required to adapt a vehicle that could "ride" a beam of light. Not only to use it as a track, but also somehow transfer energy from the beam to the vehicle until it travels beyond gravitys influence and can switch to another drive system. ( Solar?)
 
Building a vehicle that would extract energy from a light source would not be overly difficult. Making that vehicle efficient, may pose some more severe hurdles. Not to mention some basic logistics issues that would arise.

As an example let’s assume we had a ground based laser emitter that would be used to power craft up into LEO (low earth orbit). First we have to use some energy source that we convert into laser light. No matter how efficient the process, we still lose something during the conversion. We fire the beam upwards and outwards, and the atmosphere proceeds to consume large quantities of our energy due to refraction. Finally the beam reaches our craft and we lose more energy converting the light into some usable form of propulsion. Of course this is a crude example, and orbital platforms would be more efficient, but you get the point.

So basically you could do it, but it’s hard to tell if the dollars and cents of it would ever add up.

Regards,

DS638
 
Another problem I thought of would be drift. If the craft used a beam of light for energy, any environmental conditions, navigation glitches, etc...that caused the craft to slip away from the beam would result in loss of power and the craft would then answer to gravities call.

Energy conversion was a consideration, however my knowledge in this area is limited. Thank-You for your reply.
 
What you speak of, OvrLrdLegion, is being worked on.

If you are familiar at all with the "rocket equation" it relates mass fractions (payload mass & fuel mass) to the orbital velocity for any given orbital energy level. When you study the rocket equation for classical spacecraft, you see that your mass fraction of fuel as compared to total mass is WELL over 50%.

Since light is the most efficent (and fastest) form of energy, the concept of using a beam on an inertial platform aimed at a spacecraft as a means to reduce the total fuel weight on the vehicle is the "holy grail" that mankind is searching for.

Some "friends of friends" at JPL have been working on the Laser Sail as a precursor project.

RMT
 
Hello DS638,

So basically you could do it, but it’s hard to tell if the dollars and cents of it would ever add up.
Click to expand...

I suspect it is like any developing technology we have ever seen in our history: It will be incredibly expensive, and meagerly useful at first. And as we experiment and learn, efficiencies will go up and cost will come down.

For example, I can easily predict that the first application will not be "earth to orbit", because the Delta-V's (velocity changes required for orbit) are so large. However, I could easily see one of the first applications where it would make sense would be for Reaction Control System (RCS) thrusters that are used to apply small forces and moments for the purpose of "station keeping".

If you are familiar at all with the Lagrangian libration points in space, then you know that "L1" (which represents the gravity balance point between any two bodies, such as Earth-Moon) is a metastable point. This means, while the energy to maintain that position is minimum (due to its being the gravity balance point between Earth and Moon), it does require fairly frequent "station keeping" burns to maintain an object in that position. This is why we generally establish "halo orbits" centered on metastable points like L1.

A "beamrider" light track propulsion system would be ideal for this application. This would allow one to have a permanent waystation in space in a halo orbit around an L1 point. You would never need to "refuel" the station, you would simply hit it with light beams every so often to maintain its halo orbit.

In point of fact, the Earth-Moon L1 Lagrangian point is the most attractive marshalling point for missions to both the Moon and on to Mars. It is a major operational focus of NASA and their new space exploration initiative.

RMT
 
Very interesting. You know the more I time I spend in these forums, the more material I end up having to read. Alot of it isn't light reading either. /ttiforum/images/graemlins/confused.gif
The lazer sail is sort of what I was thinking.
The idea I was grappling with is if it is possible to seperate the components of some energy source and render it inert. By converging two beams ( or more) together at a particular point, perhaps within some kind of transfer device, the components are united to release the energy and operate the propulsion system of the craft.

As fiberoptics are used to transfer data, can energy be "digitized" and transfered via the same process from one point to another. The use of this type of energy transference used only to get the craft free of Earths gravitaional force and then have an alternative source for space travel...the lazer sail...etc..

These contemplations are frustrating without actually being able to build one. Would be nice to have a "lab" to create some of these experiments that are brought up in these forums. I have been searching in my garage for materials to construct a "beamrider", but I think I used up most of the plywood and duct tape on other projects around the house. /ttiforum/images/graemlins/cry.gif
 
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