- #1
pberrett
- 4
- 0
Hi everyone
I am a layman at physics am would be very grateful if someone could assist me with a question about propulsion.
The question arises from an article I recently saw discussing NASA's testing of a Cannae Drive
http://www.techtimes.com/articles/1...ight-make-deep-space-exploration-possible.htm
I am also aware of solar sail use as a method of propulsion
http://en.wikipedia.org/wiki/Solar_sail
I can see how a solar sail would work. The momentum of the photons hitting the sail imparts some of their kinetic energy into the sail and thus pushes the spacecraft .
If this is so, couldn't one simply drive a spacecraft by attaching a large focussed light/torch to the rear of the spacecraft ? In other words the light (generated from an onboard energy source) shines photons in one direction or to put it another way, provides momentum to photons going in one direction causing the spacecraft to go in the other direction. If so, would this constitute a propellantless drive for a spacecraft ? I say propellantless because light is simply a form of electromagnetic radiation at a higher frequency.
I could be wrong about this so let's consider the alternative. If shining a light in a given direction doesn't impart thrust to the attached spacecraft in the opposite direction, then couldn't I simply put a solar sail on the front of my spacecraft and shine a light on the back of it to pull the sail forward?
I think the former is more likely correct but I am interested to hear why light could not be used to propel spacecraft in this way.
cheers Peter
I am a layman at physics am would be very grateful if someone could assist me with a question about propulsion.
The question arises from an article I recently saw discussing NASA's testing of a Cannae Drive
http://www.techtimes.com/articles/1...ight-make-deep-space-exploration-possible.htm
I am also aware of solar sail use as a method of propulsion
http://en.wikipedia.org/wiki/Solar_sail
I can see how a solar sail would work. The momentum of the photons hitting the sail imparts some of their kinetic energy into the sail and thus pushes the spacecraft .
If this is so, couldn't one simply drive a spacecraft by attaching a large focussed light/torch to the rear of the spacecraft ? In other words the light (generated from an onboard energy source) shines photons in one direction or to put it another way, provides momentum to photons going in one direction causing the spacecraft to go in the other direction. If so, would this constitute a propellantless drive for a spacecraft ? I say propellantless because light is simply a form of electromagnetic radiation at a higher frequency.
I could be wrong about this so let's consider the alternative. If shining a light in a given direction doesn't impart thrust to the attached spacecraft in the opposite direction, then couldn't I simply put a solar sail on the front of my spacecraft and shine a light on the back of it to pull the sail forward?
I think the former is more likely correct but I am interested to hear why light could not be used to propel spacecraft in this way.
cheers Peter
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