Project Icarus

[Airbrush]

This is a great article I saw posted by RealityCheck in the "Iron Remnants..." discussion.

 

How do we get to the nearest stars within 100 years? We could send probes to the nearest stars traveling at 12% light speed and they could beam their discoveries back to Earth within 60 years if the probe can reach its' destination in 50 years, give it a few years to explore the star system, then 4 or more years to transmit the results of its' exploration.

 

"Project Icarus is an ambitious five-year study into launching an unmanned spacecraft to an interstellar destination. Headed by the Tau Zero Foundation and British Interplanetary Society, a non-profit group of scientists dedicated to interstellar spaceflight, Icarus is working to develop a spacecraft that can travel to a nearby star.

 

Richard Obousy, project leader and co-founder of Project Icarus, and primary propulsion lead designer, discusses the propulsion options for an interstellar probe. What makes fusion particularly appealing for propulsion is the amount of energy that it releases when compared to chemical rocket fuel. A good rule of thumb is that, pound for pound, fusion releases about a million times more energy. Because of this, it is ideally suited for interstellar propulsion.

 

In the 1970's, Project Daedalus demonstrated that with a spacecraft about the size of the Nimitz aircraft carrier, filled mostly with fusion fuel, a top speed of 12 percent the speed of light could be realized. This is truly an incredible speed, and travel to the closest star at this speed would take only 50 years.

 

One of the many challenges in actually building this technological marvel would be the creation of energies high enough to ignite the fusion reactions which could then be used to propel the spacecraft. Daedalus used a process known as "pulsed inertial confinement fusion." In this scheme, small pellets of fusion fuel would be injected at a high velocity into a reaction chamber and ignited by high energy electron beams. Conceptually, this is not vastly different from a conventional internal combustion engine, where small droplets of gasoline are injected into a combustion chamber and ignited.

 

The ignited fusion fuel would reduce the pellet to an expanding plasma radiating from the ignition point. The basic concept of the reaction chamber was to enclose the electromagnetic field of the plasma in a conducting shell. The shell would perform as a shock absorber, which would absorb the momentum of the plasma and transmit it to the vehicle. The process would occur rapidly, over a few microseconds, and the rise and fall in magnetic pressure would be received by the shell as an impulse which set it in motion.

The resulting fusion reaction products in the Daedalus reaction chamber would be channeled axially rearward from the main vehicle by a number of field coils acting as a magnetic nozzle. These ejecta would be responsible for an overall momentum transfer mediated by magnetic fields interacting with the reaction chamber.

 

The Project Icarus team is currently examining this and several other fusion propulsion schemes, and a decision regarding the main propulsion technology for Project Icarus will be made late in 2012."

 

http://news.discovery.com/space/project-icarus-fusion-propulsion-starship-110405.html

[Monsters from the ID]

I'd read about this years ago. I wonder if such a scheme is actually viable though. I know that on a large enough scale it could be carried out by kilotonne sized H-bombs, but would beam ignited pellets be able to be ignited in the first place, and if so would they output enough energy? I guess we'll know in 2012 if they follow through with their report.

 

I'd heard a nuclear salt water rocket which worked on a fissioning aqueous solution of uranium or plutonium salts. It had a pretty high specific impulse. Nowhere near that of Icarus but quite a deal higher than the NERVA kind of nuclear rocket that sends hydrogen through a hot reactor. It should be able to achieve a fairly high thrust in comparison to ion rockets, possibly comparable to chemical rockets. Sounds like that kind of propulsion would be suitable for interplanetary trips without requiring months or years long boosting and braking periods.

[Dekan]

Back in the 1950's/60's, atomic power seemed to make anything possible.

 

Project Orion envisaged atomic spaceships weighing 8,000,000 tons. These ships would cruise the solar system: the motto was - "Saturn by 1970".

 

"Give me a room full of theoretical physicists and I'll conquer the world", said an executive of a certain US company.

 

Alas, all this came to naught. I wonder why......

Edited June 18, 2011 by Dekan

[Monsters from the ID]

Back in the 1950's/60's, atomic power seemed to make anything possible.

 

Project Orion envisaged atomic spaceships weighing 8,000,000 tons. These ships would cruise the solar system: the motto was - "Saturn by 1970". ... Alas, all this came to naught. I wonder why......

 

 

An article on Project Orion says that it was the nuclear test ban treaty. They also had the oil crisis. And "Silent Spring" had also been written and the environmental movement was on the rise, so I'll bet that the idea of huge spacecraft pogoing into space using A-bombs wasn't too appealing. And I get the impression that after the moon missions were successful, the general attitude was - well we've done that now - so lets get back to concentrating on earth issues.

 

But one of these days ... Why wouldn't this technique be used? It seems to have a lot going for it. In deep space the fallout would be inconsequential. I'll tell you, from the Wikipedia article I read, the performance of these things would be incredible.

 

There is also a more recent study called the MMO (mini mag Orion) that is very interesting indeed. Frankly, I wouldn't be surprised if some governments and maybe even some multi-billionaires had done some work on this kind of thing. Who knows!