I designed a crewed interstellar spacecraft

Hi everybody,

I would like to share with you a crewed interstellar spacecraft which I have designed and called Solar One.

It employs a combination of 3 propulsion methods: nuclear fusion, beam-powered propulsion , and photon propulsion.

Basically, several compact fusion reactors power a laser system that propels a huge light sail.

Physicist Robert Forward already proposed in 1983 to use a 26-TW laser system to propel a 100-km light sail, a fresnel lens to focus the beam of the laser, and decelerate the spacecraft with a secondary light sail.

I propose something a bit different, which is to use to use for example a 60 TW-laser to propel a 5-km light sail that would deploy from the spacecraft after the acceleration stage, use parabolic mirrors that gradually change their orientation in order to focus the laser beam, and finally use a photon rocket to decelerate the spacecraft.

In theory, it could be possible to achieve 25% the speed of light, reaching the closest potentially habitable exoplanet in less than 20 years.

There are of course many challenges, like building high-energy continuous-wave lasers, reducing the weight of the nuclear fusion reactors (and of course achieving effective nuclear fusion first), and minimizing the effects of zero gravity during such a long trip.

What do you guys suggest to overcome these challenges?

This is my paper and a short video that summarizes all:

a reply to: Alfa015015

How do you plan on feeding the crew for 20 years?
How are you going to stop radiation?
And why not just send robots?

a reply to: Alfa015015

What happens when it bumps into or encounters any particulate matter along its flight path doing 25% lightspeed?

Smashing design all the same but it's going to need some kind shield or means to mitigate banging into anything because space apparently is not empty even interstellar space.

Who pays for it and does it have a toilet?

originally posted by: Alfa015015
Hi everybody,

I would like to share with you a crewed interstellar spacecraft which I have designed and called Solar One.

It employs a combination of 3 propulsion methods: nuclear fusion, beam-powered propulsion , and photon propulsion.

Basically, several compact fusion reactors power a laser system that propels a huge light sail.

Physicist Robert Forward already proposed in 1983 to use a 26-TW laser system to propel a 100-km light sail, a fresnel lens to focus the beam of the laser, and decelerate the spacecraft with a secondary light sail.

I propose something a bit different, which is to use to use for example a 60 TW-laser to propel a 5-km light sail that would deploy from the spacecraft after the acceleration stage, use parabolic mirrors that gradually change their orientation in order to focus the laser beam, and finally use a photon rocket to decelerate the spacecraft.

In theory, it could be possible to achieve 25% the speed of light, reaching the closest potentially habitable exoplanet in less than 20 years.

There are of course many challenges, like building high-energy continuous-wave lasers, reducing the weight of the nuclear fusion reactors (and of course achieving effective nuclear fusion first), and minimizing the effects of zero gravity during such a long trip.

What do you guys suggest to overcome these challenges?

This is my paper and a short video that summarizes all:

We need NO...no.... propulsion thru space w any "fuel"...but a different ....perhaps way of "drawing" us.

Just great rid of the "push with fuel" for interstellar travel...and we've not got it yet...

You have used way too much handwavium in your outline of what may lead to your eventual design. There are no details about how any of it works other than some thrust to weight and speed calculations. That might get the ship there, once the several items of proposed technology are developed, but it would be a ghost ship. Want some serious help? Look this over.

Project Rho

It covers everything about space that has been developed for hard science fiction and real life.

originally posted by: Bluntone22
a reply to: Alfa015015

How do you plan on feeding the crew for 20 years?
How are you going to stop radiation?
And why not just send robots?

Cannibalism
Tin Foil
Battery Life

a reply to: UpIsNowDown

Battery Life

Voyager

Similar probe would work with the right delivery system.

a reply to: UpIsNowDown

You better loosen your tin foil hat a bit....lol

I think this is a good effort. Every great idea starts somewhere so I hope you run with it.

a reply to: Alfa015015

at the start of the journy the acceleration and de'acceleration at the end.
would give you some gravity.
for the rest you would need to cold sleep like a Bear or Frog.
you can freeze a frog!
they are working on ways to do this.

hiting rocks in space!
you need a long range detection system.
so you can move aside.
or use the laser to brake it up.

But in space I belive there is a great deal of dust and rocks.
when a comet comes back. it all ways has a lot more dust.
just to much for a lazer and moving aside to stop.
you would need some kind of force field as well.

originally posted by: Alfa015015
There are of course many challenges, like building high-energy continuous-wave lasers, reducing the weight of the nuclear fusion reactors (and of course achieving effective nuclear fusion first), and minimizing the effects of zero gravity during such a long trip.

What do you guys suggest to overcome these challenges?

This is my paper and a short video that summarizes all:

You don't understand the sail concept you are trying to use, and it seems you don't understand basic physics like Newton's 3rd law that for every action there is an equal and opposite reaction.

As for Robert Forward's sail and NASA's "Sunjammer" sail, both more or less follow the concept described here (which your video does not):

Advanced Solar- and Laser-pushed Lightsail Concepts - Final Report

In beamed-energy propulsion, the energy source is left stationary, and the probe is pushed at a distance. Since the propulsion system does not move, the weight of the energy source is not critical, and fuel does not have to be carried.

An example of the beamed-energy propulsion is the photon-pushed sail. Since a photon has
momentum, a photon beam can “push” a reflective sail.

Note the part about "the energy source is left stationary". NASA's sunjammer was using the sun as the source of photons. Robert Forward had several concepts but he didn't take the photon source with the spacecraft, it stayed near the Earth.

So by taking the photon source with you in your design, you're totally breaking the concept to make physics work against you instead of for you, since your design in the video appears to be the light-powered version of this wind-powered contraption:


Sure the "wind" from the source pushes the sail "forward", but at the same time, the "wind" coming out of the fan is pushing the fan backward, so those forces more or less cancel. Mythbusters did a show on this and they were able to achieve a slight imbalance and get their boat moving at 3mph but it was a terrible design as unfortunately is the design shown in your video:

Mythbusters Blow your own sail full scale

At first it doesn't move forward at all. Eventually, they get it to move forward at 3mph, but the show announcer points out the stupidity of the design at time 1:50:

No doubt they'd go a lot faster with the fan facing backwards, and no sail

Yes, probably ten times as fast that way, using the laws of physics to work for you instead of against you. Then it would be more or less this airboat design:

Airboat

I think that also applies to your idea, you'd go a lot faster if you pointed the laser backwards and didn't use a sail, though still not that fast since photons don't have much momentum.

This is an idea from Robert Forward where clearly he talks about the source staying in the solar system:
Roundtrip Interstellar Travel Using Laser-Pushed Lightsails

Since the lasers will probably be in constant orbital motion about the sun while the direction to the target star (and the interstellar lightsail) stays fixed, there will be a significant pointing and tracking problem to be solved.

Not only that but his laser array in orbit will be a bit like the airboat. His laser array shoots photons out in the direction of the spacecraft, but this will accelerate his laser array in the opposite direction just like the airboat moves in the opposite direction of the air blowing out the back. At the significant power levels he's talking about for the laser array, I don't see how he expects to deal with this acceleration and keep them in orbit around the sun, and I don't see an explanation of that in his paper (unless I missed it), which seems like a gaping hole in his idea.

The Navy may have a patent for a compact fusion reactor, but there is also a Navy patent for a science fiction spacecraft with impossible performance and another patent for a perpetual motion machine which is impossible to make, so the patents mean nothing. Lockheed Martin got us excited with talk of their fusion reactor but it was just talk and some very crude experiments. They still aren't close to a working model as they described as far as I can tell.

This is what I got when I tried to see your paper. I tried later again and got the same thing, but I got enough idea from your video to understand you're trying to "blow your own sail" which is a really bad idea.

thanks for your answers !

originally posted by: Bluntone22
a reply to: Alfa015015

How do you plan on feeding the crew for 20 years?
How are you going to stop radiation?
And why not just send robots?

Yes, the spacecraft would weight 250 tons, food included.
The spacecraft would have to incorporate some shield against radiation.
Breakthrough starshot plans to send robots by 2036, it has to be a first step indeed.

originally posted by: Arbitrageur

originally posted by: Alfa015015
There are of course many challenges, like building high-energy continuous-wave lasers, reducing the weight of the nuclear fusion reactors (and of course achieving effective nuclear fusion first), and minimizing the effects of zero gravity during such a long trip.

What do you guys suggest to overcome these challenges?

This is my paper and a short video that summarizes all:

You don't understand the sail concept you are trying to use, and it seems you don't understand basic physics like Newton's 3rd law that for every action there is an equal and opposite reaction.

As for Robert Forward's sail and NASA's "Sunjammer" sail, both more or less follow the concept described here (which your video does not):

Advanced Solar- and Laser-pushed Lightsail Concepts - Final Report

In beamed-energy propulsion, the energy source is left stationary, and the probe is pushed at a distance. Since the propulsion system does not move, the weight of the energy source is not critical, and fuel does not have to be carried.

An example of the beamed-energy propulsion is the photon-pushed sail. Since a photon has
momentum, a photon beam can “push” a reflective sail.

Note the part about "the energy source is left stationary". NASA's sunjammer was using the sun as the source of photons. Robert Forward had several concepts but he didn't take the photon source with the spacecraft, it stayed near the Earth.

So by taking the photon source with you in your design, you're totally breaking the concept to make physics work against you instead of for you, since your design in the video appears to be the light-powered version of this wind-powered contraption:

Sure the "wind" from the source pushes the sail "forward", but at the same time, the "wind" coming out of the fan is pushing the fan backward, so those forces more or less cancel. Mythbusters did a show on this and they were able to achieve a slight imbalance and get their boat moving at 3mph but it was a terrible design as unfortunately is the design shown in your video:

Mythbusters Blow your own sail full scale

At first it doesn't move forward at all. Eventually, they get it to move forward at 3mph, but the show announcer points out the stupidity of the design at time 1:50:

No doubt they'd go a lot faster with the fan facing backwards, and no sail

Yes, probably ten times as fast that way, using the laws of physics to work for you instead of against you. Then it would be more or less this airboat design:

Airboat

I think that also applies to your idea, you'd go a lot faster if you pointed the laser backwards and didn't use a sail, though still not that fast since photons don't have much momentum.

This is an idea from Robert Forward where clearly he talks about the source staying in the solar system:
Roundtrip Interstellar Travel Using Laser-Pushed Lightsails

Since the lasers will probably be in constant orbital motion about the sun while the direction to the target star (and the interstellar lightsail) stays fixed, there will be a significant pointing and tracking problem to be solved.

Not only that but his laser array in orbit will be a bit like the airboat. His laser array shoots photons out in the direction of the spacecraft, but this will accelerate his laser array in the opposite direction just like the airboat moves in the opposite direction of the air blowing out the back. At the significant power levels he's talking about for the laser array, I don't see how he expects to deal with this acceleration and keep them in orbit around the sun, and I don't see an explanation of that in his paper (unless I missed it), which seems like a gaping hole in his idea.

The Navy may have a patent for a compact fusion reactor, but there is also a Navy patent for a science fiction spacecraft with impossible performance and another patent for a perpetual motion machine which is impossible to make, so the patents mean nothing. Lockheed Martin got us excited with talk of their fusion reactor but it was just talk and some very crude experiments. They still aren't close to a working model as they described as far as I can tell.

This is what I got when I tried to see your paper. I tried later again and got the same thing, but I got enough idea from your video to understand you're trying to "blow your own sail" which is a really bad idea.

The laser system would be placed outside the spacecraft, probably in some Lagrange point.
The only laser in the spacecraft is the photon rocket, which is necessary to decelerate.

originally posted by: andy06shake
a reply to: Alfa015015

What happens when it bumps into or encounters any particulate matter along its flight path doing 25% lightspeed?

Smashing design all the same but it's going to need some kind shield or means to mitigate banging into anything because space apparently is not empty even interstellar space.

As in the Starshot project, the spacecraft indeed needs to have a special coating that erodes with time due to the impact of dust and micro-asteroids.

originally posted by: Alfa015015
The laser system would be placed outside the spacecraft, probably in some Lagrange point.
The only laser in the spacecraft is the photon rocket, which is necessary to decelerate.

The first screenshot from your animation is at about 31 seconds. It's hard to see the source off in the distance, but the laser light is striking the sail.


Then at about 40 seconds it looks like the source of the light is coming from the spacecraft, doesn't it? Did the man making your animations make a mistake to show it this way?


These animation screenshots don't seem to show what you described in your reply.

The only laser in the spacecraft is the photon rocket, which is necessary to decelerate.

What is a photon rocket, exactly? Wouldn't it take the same amount of energy to slow down as it did to speed up? Why not just use the "photon rocket" in the first place? Since you have it.

I like the "own bootstraps" concept though. It's fun.

a reply to: Alfa015015

Wouldn't placing an array at Lagrangian point make the energy demand exponentially high? There'd need to be several placed at L points in order to maintain contact and counteract gravitational lensing. Each would need a nuclear fusion reactor in place to produce the energy required.

It'd be far more effective, cheaper and reliable to use the Sun as the source of photons or an ion thruster.

The base idea is interesting and a good one but in my opinion you've fallen into the trap of over engineering the design which dramatically increases the risk of something going wrong and adds unnecessary weight to an aircraft/ spaceship. It's best to design stuff as simple and using the least amount of components possible to maximize efficiency, reliability and longevity of components.