Hello. I hope I'm posting this in the right place.
I'm writing a story that concerns space travel; not something that I know a whole bunch about. My biggest problem is “what will propel the ship?” This ship must be able to get to the Ross128 star system (11 light years from earth).
QUESTION #1 COULD THE FOLLOWING PROPELSION SYSTEM ACHIEVE MY GOAL?
I’m considering using photons. I’ve found some stuff on the internet that suggests this may be the most economical choice.
Even though photons have no mass, the microscopic particles of light do possess both energy and momentum. With a large, reflective sail, and sufficient quantities of photons, would it be possible to generate enough momentum to gradually accelerate a spacecraft to .9 light speed? And could this continue to propel the ship for the period of time it would take to arrive? Below is excerpts from the ship description from a rough draft. I’m curious if this would make sense?
Please ignore grammar ect., it’s a rough draft
“An advantage of using photons as fuel was that the spaceship literally did not have to carry any fuel or engines. So, other than the mirrors and the sail, the rest of the ships mass could be made up of payload and the ships actual structure. This allows the craft to be many times smaller than other types of experimental spacecraft, such as rockets, that have to be capable of storing massive amounts of fuel.
The ship would be a pair of spacecraft linked by a long metal tube. The one in front is the actual ship, a small metal pod that provides living space and a 200-meter mirror.
Trailing behind the main ship is the towed propulsion system. This holds another 200 meter mirror and a giant sail (which looks like a huge aluminum parachute), into which the photons are bounced into, creating the momentum that accelerates the ship. The space between the two ships and their mirrors forms an active resonant optical cavity between them. By bouncing photons back and forth between the mirrors thousands of times, this amplifies the photon thrust by orders of magnitude.
A massive mirror located on earth reflects a laser to the spacecraft, providing the photons.
The light photons, bouncing between the mirrors and finally the sail, push the craft to incredible speeds, falling just short of the speed of light. Something called the “doppler shift” insures that, as the ship accelerates, the reflective process gains efficiency. So, as the spacecraft’s velocity drew near the speed of light, the efficiency of photon propulsion approaches nearly 100%, which translates to her incredible speed.
The goal is .90 speed of light.”
So, could a laser on earth pull this off? Hoping I can get some help from the experts here! Any opinions and advice on what I should do here (scrap the whole idea?) appreciated.
Oh, and one easier question:
QUESTIONS #2 TIME RADIO MESSAGE FROM NEPTUNE TO EARTH AT CLOSEST POINT?
I'm writing a story that concerns space travel; not something that I know a whole bunch about. My biggest problem is “what will propel the ship?” This ship must be able to get to the Ross128 star system (11 light years from earth).
QUESTION #1 COULD THE FOLLOWING PROPELSION SYSTEM ACHIEVE MY GOAL?
I’m considering using photons. I’ve found some stuff on the internet that suggests this may be the most economical choice.
Even though photons have no mass, the microscopic particles of light do possess both energy and momentum. With a large, reflective sail, and sufficient quantities of photons, would it be possible to generate enough momentum to gradually accelerate a spacecraft to .9 light speed? And could this continue to propel the ship for the period of time it would take to arrive? Below is excerpts from the ship description from a rough draft. I’m curious if this would make sense?
Please ignore grammar ect., it’s a rough draft

“An advantage of using photons as fuel was that the spaceship literally did not have to carry any fuel or engines. So, other than the mirrors and the sail, the rest of the ships mass could be made up of payload and the ships actual structure. This allows the craft to be many times smaller than other types of experimental spacecraft, such as rockets, that have to be capable of storing massive amounts of fuel.
The ship would be a pair of spacecraft linked by a long metal tube. The one in front is the actual ship, a small metal pod that provides living space and a 200-meter mirror.
Trailing behind the main ship is the towed propulsion system. This holds another 200 meter mirror and a giant sail (which looks like a huge aluminum parachute), into which the photons are bounced into, creating the momentum that accelerates the ship. The space between the two ships and their mirrors forms an active resonant optical cavity between them. By bouncing photons back and forth between the mirrors thousands of times, this amplifies the photon thrust by orders of magnitude.
A massive mirror located on earth reflects a laser to the spacecraft, providing the photons.
The light photons, bouncing between the mirrors and finally the sail, push the craft to incredible speeds, falling just short of the speed of light. Something called the “doppler shift” insures that, as the ship accelerates, the reflective process gains efficiency. So, as the spacecraft’s velocity drew near the speed of light, the efficiency of photon propulsion approaches nearly 100%, which translates to her incredible speed.
The goal is .90 speed of light.”
So, could a laser on earth pull this off? Hoping I can get some help from the experts here! Any opinions and advice on what I should do here (scrap the whole idea?) appreciated.
Oh, and one easier question:
QUESTIONS #2 TIME RADIO MESSAGE FROM NEPTUNE TO EARTH AT CLOSEST POINT?