Could We Reach Alpha Centauri in Just 132 Years with an Orion Drive?

In summary, there are multiple proposed methods for interstellar travel, including using a VASIMR rocket or an Orion drive. However, Robert Forward has suggested a different approach involving a stationary laser on Earth, a large Fresnel lens in space, and a starship with a sail. This could potentially make a voyage to Alpha Centauri only ten years long. There are concerns about the accuracy and safety of this method, as well as the energy required. Another proposed method is the Alcubierre drive, which involves creating a bubble of space around the ship to travel faster than light. However, these technologies are still in development and there are various challenges and limitations to consider.
  • #1
meteor
940
0
Using a VASIMR rocket, 1320 years of voyage are needed
Using an Orion drive, the duration of the voyage is 132 years
 
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  • #2
I fail to see the relevance in this thread, but bon voyage anyways...
 
  • #3
Good news!

I've just read what Robert Forward has proposed for a travel to Alpha Centauri.He proppose to construct a laser with a power of 10 million Gigawatts.the laser will be stationary on earth. Outside the earth, you let floating a Fresnel lens of a thousand km diameter. Then construct a starship with a sail of one thousand km long. Making the laser light pass through the lens and impacting on the sail it can provide a big impulse to the starship. With this system the voyage to Alpha Centauri is only ten years long!

Yeah!
 
  • #4
Interesting theory, but what if they miss?;)

Whoah Momma!
 
  • #5
Not to mention the lens. How are they going to put it in orbit?
And the military implications of the laser? (knocking down satellites...)
 
  • #6
and the simple wondering of how they would get back :) maybe if the laser was rigged to the starship itself it may work.

and does the laser have to stay on ?
 
  • #7
Yeah, the return trip came to my mind as well.

I agree with Bunting's statement about the laser being attached to the rocket when it comes to the return trip.

Then again, wouldn't you have to take into consideration Einstein's Theory of Relativity (time dilation, etc.)?
 
  • #8
The laser couldn't be mounted to the back of the rocket. It's called the conservation of linear momentum.

- Warren
 
  • #9
Have you but any thought into the amount of energy required to make this happen? If I recall correctly going by energy/mass equivelence there may not be sufficient mass in the solar system to make a trip at that speed. Minor detail, why would you worry about it.
 
  • #10
The laser couldn't be mounted to the back of the rocket. It's called the conservation of linear momentum.

<slaps himself really hard on the head>
 
  • #11
There are a few problems with a spacecraft traveling about 1/3 C as it leaves our solar system. If it’s a one-way mission, it will likely need a course correction early on using on-board engines with limited fuel supply. Communications to the craft will have to be at a higher frequency to compensate for the Doppler shift. Communications from the craft will be received at a lower frequency. As the craft approaches Alpha Centauri, we’d probably want to shoot some photos. Again due to the Doppler shift, normal optics would not focus. It would probably be better to use X-ray imaging. Perhaps the laser sail could be used as an x-ray receiver.

If it’s meant to be a round-trip mission, there’s no way to turn around with conventional rocketry but the gravitational field of the Alpha Centauri system could be used to do a 180. Since that system has at least 2 stars, its might be possible to get a gravitational velocity boost and return to Earth at a higher velocity. Of course the forces on the star craft would be enormous as it does the 180, but perhaps a converted nuclear sub might make it.

Now were approaching the solar system at 1/3 C+ we need to fire up the laser again to put the brakes on or find out what happens when a nuclear sub traveling at 1/3C hits the sun.

Just having fun.
 
  • #12
Originally posted by chroot
The laser couldn't be mounted to the back of the rocket. It's called the conservation of linear momentum.

- Warren
Sure it could. You point it BACKWARDS and take away the sail.

Its like the old cliche' of setting up a fan in your sail boat to blow against the sail. It doesn't work, but if you turn the fan around and point it backwards, it works just fine (they use them in swamps).

Of course there are negatives to doing it that way - half the thrust and the added weight.
 
  • #13
OK, who's into build this thing?
 
  • #14
Originally posted by Guybrush Threepwood
OK, who's into build this thing?

ME ME! Let me just check my bank account













damn never mind :(
 
  • #15
I've found new information about the project. The laser would be orbiting Mercury, using then the Sun's photons to excite the laser.
The lens would be located between Saturn and Uranus and would have a mass of 569 million kg (560000 tons)
A complete info of the project by the same Robert Forward can be found here:
http://planetary.org/interstellar/forward.html [Broken]

There's a system that could permit to travel faster than light: the Alcubierre drive. Consists of create a bubble of space around you and make that bubble travel through space faster than light. It doesn't violate relativity, because in the space inside the bubble you are not traveling faster than light.
 
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  • #16
You don't launch the lens and such. You build them in space, preferably using some function nanotech thingies to form an absolutely perfect lens. I would guess we are only a couple of decades away from such capability.

You don't shoot a big laser at the spaceship because there's no big laser on the other end to shoot it to slow it down. Or I suppose using nukes at the far end to slow it down (ie. Orion Project) could be done.
 
  • #17
Originally posted by GENIERE
There are a few problems with a spacecraft traveling about 1/3 C as it leaves our solar system. If it’s a one-way mission, it will likely need a course correction early on using on-board engines with limited fuel supply. Communications to the craft will have to be at a higher frequency to compensate for the Doppler shift. Communications from the craft will be received at a lower frequency. As the craft approaches Alpha Centauri, we’d probably want to shoot some photos. Again due to the Doppler shift, normal optics would not focus. It would probably be better to use X-ray imaging. Perhaps the laser sail could be used as an x-ray receiver.

If it’s meant to be a round-trip mission, there’s no way to turn around with conventional rocketry but the gravitational field of the Alpha Centauri system could be used to do a 180. Since that system has at least 2 stars, its might be possible to get a gravitational velocity boost and return to Earth at a higher velocity. Of course the forces on the star craft would be enormous as it does the 180, but perhaps a converted nuclear sub might make it.

Now were approaching the solar system at 1/3 C+ we need to fire up the laser again to put the brakes on or find out what happens when a nuclear sub traveling at 1/3C hits the sun.

Just having fun.

The gravity of the system could not be used to turn around at 1/3 c. The radius would have to be miniscule, and this is not possible as the star is not miniscule.
 
  • #18
1/3C slingshot anybody?
 

1. How long would it take to reach Alpha Centauri?

The estimated time it would take to reach Alpha Centauri depends on the mode of transportation. With current technology, it would take approximately 100,000 years to reach Alpha Centauri. However, with advanced spacecraft and propulsion systems, it could potentially be reduced to 20 to 50 years.

2. Can humans survive the journey to Alpha Centauri?

The journey to Alpha Centauri would take a significant amount of time, so it is currently not possible for humans to survive the journey due to limitations in resources and technology. However, with advancements in technology and spacecraft design, it may be possible for humans to survive the journey in the future.

3. Will we find another habitable planet in Alpha Centauri?

There is currently no conclusive evidence of a habitable planet in Alpha Centauri. However, it is estimated that there could potentially be one or more Earth-sized planets in the habitable zone of the star system. Further exploration and research will be needed to determine if any of these planets could support life.

4. How would we travel to Alpha Centauri?

Currently, the most feasible way to travel to Alpha Centauri would be through advanced spacecraft powered by nuclear fusion or antimatter propulsion. These technologies are still in the development stage and would require significant advancements to make the journey possible.

5. What are the potential risks of traveling to Alpha Centauri?

The journey to Alpha Centauri would present many risks, including exposure to cosmic radiation, prolonged isolation and confinement, and potential technical failures. Additionally, the psychological and physiological effects on humans during such a long journey are still largely unknown. Extensive research and preparation would be necessary to mitigate these risks before attempting the journey.

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