Beaming rockets into space

Jan 21, 2011 By Prachi Patel
A space shuttle launch, using traditional chemical rockets. Credit: NASA

Space launches have evoked the same image for decades: bright orange flames exploding beneath a rocket as it lifts, hovers and takes off into the sky. But an alternative propulsion system proposed by some researchers could change that vision.

Instead of explosive on-board a rocket, the new concept, called beamed thermal propulsion, involves propelling a rocket by shining or microwaves at it from the ground. The technology would make possible a reusable single-stage rocket that has two to five times more payload space than conventional rockets, which would cut the cost of sending payloads into low-Earth orbit.

NASA is now conducting a study to examine the possibility of using beamed energy propulsion for space launches. The study is expected to conclude by March 2011.

In a traditional chemical rocket , fuel and oxidizer are pumped into the under high pressure and burnt, which creates exhaust gases that are ejected down from a nozzle at high velocity, thrusting the rocket upwards.

A beamed thermal propulsion system would involve focusing microwave or laser beams on a aboard the rocket. The heat exchanger would transfer the radiation's energy to the , most likely hydrogen, converting it into a hot gas that is pushed out of the nozzle.

A conceptual microwave-propelled lightcraft receives microwave beams from an array of microwave sources on the ground. Credit: Kevin Parkin

“The basic idea is to build rockets that leave their energy source on the ground,” says Jordin Kare, president of Kare Technical Consulting, who developed the laser thermal launch system concept in 1991. “You transmit the energy from the ground to the vehicle.”

With the beam shining on the vehicle continually, it would take 8 to 10 minutes for a laser to put a craft into orbit, while would do the trick in 3 to 4 minutes. The vehicle would have to be designed without shiny surfaces that could reflect dangerous beams, and aircraft and satellites would have to be kept out of the beam’s path. Any launch system would be built in high-altitude desert areas, so danger to wildlife shouldn’t be a concern, Kare says.

Thermal propulsion vehicles would be safer than chemical rockets since they can’t explode and don’t drop off pieces as they fly. They are also smaller and lighter because most of the complexity is on the ground, which makes them easier and cheaper to launch.

“People can launch small satellites for education, science experiments, engineering tests, etc. whenever they want, instead of having to wait for a chance to share a ride with a large satellite,” Kare says.

An artist’s rendering of a laser launch system. Each beam module can fit on a shipping container. Credit: Jordin Kare

Another cost advantage comes from larger payload space. While conventional propulsion systems are limited by the amount of chemical energy in the propellant that's released by combustion, in beamed systems you can add more energy externally. That means a spacecraft can gain a certain momentum using less than half the amount of propellant of a conventional system, allowing more room for the payload.

“Usually in a conventional rocket you have to have three stages with a payload fraction of three percent overall,” says Kevin Parkin, leader of the Microwave Thermal Rocket project at the NASA Ames Research Center. “This propulsion system will be single stage with a payload fraction of five to fifteen percent.”

Having a higher payload space along with a reusable rocket could make beamed thermal propulsion a low-cost way to get material into low Earth orbit, Parkin says.

Parkin developed the idea of microwave thermal propulsion in 2001 and described a laboratory prototype in his 2006 PhD thesis. A practical real-world system should be possible to build now because microwave sources called gyrotrons have transformed in the last five decades, he says. One megawatt devices are now on the market for about a million US dollars.

"They're going up in power and down in cost by orders of magnitude over the last few decades,” he says. “We've reached a point where you can combine about a hundred and make a launch system."

Meanwhile, the biggest obstacle to using lasers to beam energy has been the misconception that it would require a very large, expensive laser, Kare says. But you could buy commercially available lasers that fit on a shipping container and build an array of a few hundred. "Each would have its own telescope and pointing system," he says. "The array would cover an area about the size of a golf course."

The smallest real laser launch system would have 25 to 100 megawatts of power while a microwave system would have 100 to 200 megawatts. Building such an array would be expensive, says Kare, although similar to or even less expensive than developing and testing a chemical rocket. The system would make most economic sense if it was used for at least a few hundred launches a year.

In addition, says Parkin, “the main components of the beam facility should last for well over ten thousand hours of operation, typical of this class of hardware, so the savings can more than repay the initial cost.”

In the near term, beamed energy propulsion would be useful for putting microsatellites into low Earth orbit, for altitude changes or for slowing down spacecraft as they descend to Earth. But the technology could in the future be used to send missions to the Moon or to other planets and for space tourism.

Kare has looked into the possibility of using lasers to propel interstellar probes for ’s Institute of Advanced Concepts. A deep space launch would require higher power lasers with larger telescope systems as well as laser relay stations in space. Powering missions over interplanetary distance would require even bigger lasers and telescopes, as well as different propulsion techniques using propellants easier to store than liquid hydrogen.

Sending a spacecraft to a moon of Jupiter, for instance, would require a laser that gives billions of watts of power. "You'd have to have another couple generations of space-based telescopes to do something like that,” Kare says. “You can in fact launch an interstellar probe that way but now you’re talking about lasers that might be hundreds of billions of Watts of power." Laser technology could reach those levels in another 50 years, he says.

Explore further: NASA to make announcement on US human spaceflights

Related Stories

Powering cube satellites

Feb 03, 2010

Right now, 10 to 15 Rubik's Cube-sized satellites are orbiting high above Earth. Known as cube satellites, or "CubeSats," the devices help researchers conduct simple space observations and measure characteristics ...

Princeton wins NASA Competition to Develop Plasma Rocket

Aug 30, 2004

NASA has selected engineers at Princeton University to develop an advanced rocket thruster that could send people or robots to other planets with far less propellant than conventional engines. The National Aeronautics and Sp ...

NASA modifies launch vehicle contract

Oct 05, 2006

NASA is extending a contract with ATK Thiokol of Brigham City, Utah, to continue developing the first stage for the Ares I crew launch vehicle.

Recommended for you

Image: Crescent Mimas

11 hours ago

A thin sliver of Mimas is illuminated, the long shadows showing off its many craters, indicators of the moon's violent history.

User comments : 49

Adjust slider to filter visible comments by rank

Display comments: newest first

Quantum_Conundrum
1.1 / 5 (8) Jan 21, 2011
Regarding interstellar travel:

Your primary laser would need to be on the surface of the moon, or on an orbital platform or dyson swarm in order to accomplish this. Additionally, you'd need a completely ludicrous degree of accuracy and precision in your targeting system if you seriously wanted to power a craft to say, 0.01c or greater. Not to mention, relativistic consequences have never actually been tested with regards to prolonged deep space craft acceleration and escaping the solar system's gravity. If calculations are off by a nanometer or nanosecond, you die?
CHollman82
3.4 / 5 (5) Jan 21, 2011
Regarding interstellar travel:

Your primary laser would need to be on the surface of the moon, or on an orbital platform or dyson swarm in order to accomplish this. Additionally, you'd need a completely ludicrous degree of accuracy and precision in your targeting system if you seriously wanted to power a craft to say, 0.01c or greater. Not to mention, relativistic consequences have never actually been tested with regards to prolonged deep space craft acceleration and escaping the solar system's gravity. If calculations are off by a nanometer or nanosecond, you die?


You realize that lasers disperse even in space, right? Meaning that the energy received drops off exponentially with distance from the source... Meaning that such a system will not apply significant acceleration for very long at all.
lexington
3.7 / 5 (3) Jan 21, 2011
Who could object to having a nation build a tremendous array of incredibly powerful lasers?
Quantum_Conundrum
1.4 / 5 (5) Jan 21, 2011
You realize that lasers disperse even in space, right? Meaning that the energy received drops off exponentially with distance from the source... Meaning that such a system will not apply significant acceleration for very long at all.


They do disperse, but not according to the inverse square law. The whole reason regular EM radiation disperses is the sperical nature of the wave propagation, which naturally leads to the inverse square law since surface area of a sphere is the square of radius.

Lasers do not dispers in exactly the same manner because they are coherent.

Additionally, this system would only be useful for a probe on a fly-by mission, because it offers no solution for the braking phase of travel on the other end. So the craft wouldn't be able to slow down to an orbital velocity for the distant star or planet. You'd only have a one-shot fly-by, like the New Horizons spacecraft passing Pluto...
apex01
not rated yet Jan 21, 2011
I'd rather have a laser holocaust than a nuclear holocaust.
bugmenot23
4.2 / 5 (5) Jan 21, 2011
Sounds impractical, my money is on the Skylon, Spaceship One and other Single-stage-to-orbit craft.
CHollman82
1.5 / 5 (2) Jan 21, 2011
Additionally, this system would only be useful for a probe on a fly-by mission, because it offers no solution for the braking phase of travel on the other end. So the craft wouldn't be able to slow down to an orbital velocity for the distant star or planet. You'd only have a one-shot fly-by, like the New Horizons spacecraft passing Pluto...


True, if we could scatter these stations throughout the solar system they could be used as relays to either accelerate or brake space craft that pass them by... that would be useful... I was mostly commenting on the idea of reaching any large fraction of light speed with such a system, I doubt it would be possible with current technology to reach even 1%
Pyle
1.7 / 5 (3) Jan 21, 2011
What a novel idea!
I wonder if we could get elephants into space with it?
rgwalther
not rated yet Jan 21, 2011
What a novel idea!
I wonder if we could get elephants into space with it?

Sure Gomer, why not?
rgwalther
not rated yet Jan 21, 2011
I'd rather have a laser holocaust than a nuclear holocaust.

I don't rightly care what either 'caust'.
GSwift7
3.4 / 5 (5) Jan 21, 2011
Well, if your objective is to reach 1%, then a system like this might help. You could launch your ship in pieces using this system and assemble it in orbit. You could use this system to get conventional fuel into orbit for your ship as well. Then once the ship is assembled you could use something like an ion thruster for the actual journey. I don't have the numbers, so this is just a guess, but I would bet this system only makes sense financially speaking as a ground based launch assist system. Launching the lasers into space kinda seems like you're defeating the purpose, doesn't it?
ShotmanMaslo
1 / 5 (1) Jan 21, 2011

Additionally, this system would only be useful for a probe on a fly-by mission, because it offers no solution for the braking phase of travel on the other end. So the craft wouldn't be able to slow down to an orbital velocity for the distant star or planet. You'd only have a one-shot fly-by, like the New Horizons spacecraft passing Pluto...


You could channel the expanding gas to different directions quite easily, so even braking would be possible, assuming you laser is coherent enough to reach a few lightyears (probably not).
Nik_2213
1 / 5 (1) Jan 21, 2011
"only be useful for a probe on a fly-by mission, because it offers no solution for the braking phase of travel on the other end"

If you're talking solar-sail probes, IIRC, this issue has been solved: The sail is circular, and the outer ring 'stages' when braking begins. It reflects beamed energy back, onto the probe's now smaller sail, slowing it...
eachus
5 / 5 (1) Jan 21, 2011
I was mostly commenting on the idea of reaching any large fraction of light speed with such a system, I doubt it would be possible with current technology to reach even 1%


You are missing a blindingly obvious point. Let's Imagine a system using LiH (very solid) fuel to deal with the long term fuel storage issue.

Launch is of course near the laser array on Earth, and achieves LEO before the launch vehicle passes beyond the horizon. In a later orbital pass over the laser array you provide enough delta-v to put it on a free return trajectory around the moon. When it returns to Earth? Hit it again, this time sending it to Jupiter.

At Jupiter, the launcher makes a right turn, just using orbital mechanics, and it is on a Sun grazing elliptical orbit. As it approaches the Sun the main engines fire again--no need for lasers with the Sun right there. Delta-v close to the Sun can preserve much of the velocity from falling into the Sun's gravity well.
lengould100
1 / 5 (1) Jan 21, 2011
At 1% C, or 300,000 x .01 x 3,600 = 10.8 million kph, there would be NO way to return from a star on the same path you aproached by doing a "fly-by", because the radius of the turn at the far star would be below its surface. And, if done in a system such as ours, the total time for planetary observations from within 1 AU of an orbit 1 AU from the star would be about 16 hours.

Thats a lot of effort and treasure for a 16 hour fly-by.
Quantum_Conundrum
1 / 5 (2) Jan 21, 2011
Launching the lasers into space kinda seems like you're defeating the purpose, doesn't it?


Nope. It would give you a longer range and better precision as the craft gets farther away.

You launch lasers into space using the ground-based lasers. Then for your deep space probe, you'd launch from the ground using ground-based lasers, then once it gets into space you continue to accelerate using space-based lasers.

Of course, with existing space program caliber solar panels, you'd need an orbital solar array of dimensions roughly 1km x 2.65km in order to power just one gigawatt laser...In order to get the hundreds of gigawatts of power for interstellar probe, you'd need 10km by 26.5km solar array.

In the near future this is impossible, but it might be possible in several decades if self-replicating lunar robots can be invented to construct such megastructures.
antialias_physorg
5 / 5 (3) Jan 21, 2011
I'll try a bit of math here to see whether we can use his to go interstellar (or even interplanetary):

goal: accelerate to 1 percent of c
acceleration: they say they can get to orbit (I suppose this means LEO = 200km in 3-4 minutes). Using the 3 minute mark this means an acceleration of 1.2g. Let's add a g because when we accelerate in space we don't have to work against earth gravity: so that's 2.2g we can get from a space battery of lasers.

To get to 3000km/sec at 2.2g takes roughly 38 hours by which time you have travelled some 204 million kilometers (which is one and a half times the distance between the earth and the sun)

And no: lasers do NOT stay focussed over these distances. Not by a very long shot.

Note that the craft in the article do not lug around enough acceleration mass for 40 hours but for just 3-4 minutes. More mass sharply reduces the acceleration (or drastically increases the laser power needed). As for braking? Who's gonna brake you at the destination?
Quantum_Conundrum
1.7 / 5 (3) Jan 21, 2011
antialias:

For the longer ranged or deep space probe, the alleged 100 gigawatts of lasers should be able to produce something like 1 meganewton of thrust.

If you had an un-manned probe ten times the mass of the Voyager probes, which were about 1500kg, you could still accelerate at 66.66 m/s^2, or about 6.7g until the craft was out of safe operational range.

Round trip to the moon at apogee is about 811,000km and we use reflectors and lasers to measure it. So lasers are useful at least over a distance of 811,000km.

So with the proposed 100 gigawatts of lasers you should be able to accelerate an unmanned probe of ten Voyager masses for roughly 4932 seconds, obtaining a velocity of 329 km/s, or about 1/1000th of c...
antialias_physorg
5 / 5 (5) Jan 21, 2011
And you're going to produce 100 gigawatts of power in orbit...how? And remember: pumping lasers is awfully inefficient so you'd need at least a terrawatt or more.

Also: a craft that weighs 1500kg (assuming 99% of that were reaction mass) could accelerate for...erm.. a minute or so until all mass was used up? Not nearly enough. Pile on more (reaction)mass and the acceleration drops proportionally.

This type of thrust is high mass, high impulse, low speed (as opposed to ion engines which are low mass, low impulse but high speed).

The laser idea is for getting craft off the ground because we need to constantly exceed the 1g pull of earth.

In space ion engines are _way_ better. 0.01g for months/years beats a short burst of high acceleration any time. And you have a thruster which will give you the option to slow down at ypur destination (something you don't have with the laser boost mechanism)
Moebius
3 / 5 (2) Jan 21, 2011
Who could object to having a nation build a tremendous array of incredibly powerful lasers?


If it was on earth they wouldn't object because you couldn't point it at anyone easily. On the near side of the moon would be a different story. I would think that neither would be very good for space travel. Maybe on a lunar pole or Antarctica. The best solution would be a Deathstar and no one would object to that (at least not after it was operational).
antialias_physorg
5 / 5 (1) Jan 21, 2011
If it was on earth they wouldn't object because you couldn't point it at anyone easily.

Small mirror(s) in orbit? With 2 of those you could target any place on earth from an earthbound firing station.

Would be a lot more effective than on the near side of the moon (because the distance would be orders of magnitude smaller to the target)
gwrede
4 / 5 (4) Jan 21, 2011
Sending a spacecraft to a moon of Jupiter, for instance, would require a laser that gives billions of watts of power. "You'd have to have another couple generations of space-based telescopes to do something like that," Kare says.
This author, like most of the commentators here talk about lasers and their output power like it would come out of thin air. A "laser that gives out billions of watts" would need a nuclear power plant for each billion watt. (And that at 100% efficiency, whch they really don't have!)
"You can in fact launch an interstellar probe that way but now you’re talking about lasers that might be hundreds of billions of Watts of power." Laser technology could reach those levels in another 50 years, he says.
Again, here we'd need hundreds of nuclear power plants around the laser station.

And by then nuclear is out of fashion. So, try this with wind or solar power. ROTFLMAO!

Quantum_Conundrum
1 / 5 (3) Jan 21, 2011
Again, here we'd need hundreds of nuclear power plants around the laser station.


No, you wouldn't. You could power the ground-based lasers using solar power. You'd need a rather large solar farm.

Commercial grade solar panels right now make about 220 watts per 1.5 square meters.

So 1 billion watts divided by 220 watts, and then multiply by 1.5 square meters to get the area of panels needed for 1 gigawatt.

My numbers above assumed ISS grade solar panels. Here I assume commercial grade solar panels.

1000000000 * 1.5 / 220 = 6818181m^2

which is 1km x 6.818km of solar panels per gigawatt, which is 2.664 square miles.

And you're going to produce 100 gigawatts of power in orbit...how?


In theory, you would eventually have a giant array of solar panels on the moon, constructed by self-replicating robots.
Quantum_Conundrum
1 / 5 (3) Jan 21, 2011
The U.S. military is currently able to fit a 150kw liquid laser anti-missile system onto a humvee. The mass of the system is less than 750kg, and the volume is less than 2 cubic meters.

Of course, it would take almost 700,000 of these to make 100 gigawatts...
TheGhostofOtto1923
1 / 5 (6) Jan 21, 2011
At 1% C, or 300,000 x .01 x 3,600 = 10.8 million kph, there would be NO way to return from a star on the same path you aproached by doing a "fly-by", because the radius of the turn at the far star would be below its surface. And, if done in a system such as ours, the total time for planetary observations from within 1 AU of an orbit 1 AU from the star would be about 16 hours.
You could drop a solar-powered laser in orbit around the far star for the power you need to get back home, or preposition it as a separate mission -?

-And aren't we supposed to have solar power stations in orbit soon? Couldn't they serve dual purpose for placing payloads in orbit? Or burning cities lexington? Inappropriate uses will be impossible once we have world govt and everybody are brothers. 8-/
Question
1 / 5 (1) Jan 21, 2011
Wouldn't a group of lasers powerful enough to launch a rocket simply disintegrate the spaceship before it even got off the ground?
trekgeek1
5 / 5 (2) Jan 21, 2011
Not liking it. I don't like ships that don't have their power source on board (propulsion, I know it'll have power systems). It just seems odd to me. I think Skylon is the best bet. I hope they don't build this since I believe it will slow progress on developing new engine technologies. When you have something that works, you aren't likely to build new systems that have potentially higher pay offs.
rwinners
1 / 5 (1) Jan 21, 2011
"They're going up in power and down in cost by orders of magnitude over the last few decades,” he says. “We've reached a point where you can combine about a hundred and make a launch system."

OK, then how about just using one and a small model as proof o concept?
rwinners
1 / 5 (1) Jan 21, 2011
q/"They're going up in power and down in cost by orders of magnitude over the last few decades,” he says. “We've reached a point where you can combine about a hundred and make a launch system."/q

Ok, then how about using just one module and a small model to provide proof of concept? I mean, companies are spending multiple millions of dollars developing private lift capability right now. Why aren't the using this technology?
stvnwlsn
not rated yet Jan 21, 2011
Do we have the technology to build a heat exchanger cabable of redistributinhg that much heat without overheating and a targeting system to keep it from hitting other parts of the craft?

If microwaves were used how would you shield the occupants and electrical systems to keep them from frying?
BillFox
3 / 5 (2) Jan 22, 2011
Regarding interstellar travel:

Your primary laser would need to be on the surface of the moon, or on an orbital platform or dyson swarm in order to accomplish this. Additionally, you'd need a completely ludicrous degree of accuracy and precision in your targeting system if you seriously wanted to power a craft to say, 0.01c or greater. Not to mention, relativistic consequences have never actually been tested with regards to prolonged deep space craft acceleration and escaping the solar system's gravity. If calculations are off by a nanometer or nanosecond, you die?


I still don't know whether you simply hate and wish to discredit science, or are merely a runner in the special olympics. In either regard, do you not tire of further ruining any shred of a reputation you might have left? Almost as bad as Skeptic Heretic...
Pyle
1 / 5 (1) Jan 22, 2011
stvnwlsn:
The only real obstacle here is the lasers. As I hinted at above, this is not a new idea. It has been floating around in sci-fi books for at least 30 years and likely before that.

The targeting is straightforward and shouldn't be an issue for the first LEO launches. Shielding follows the targeting and really shouldn't be an issue. The heat exchanger and propellant would be the new tech, but, again, the laser had been the sticking point.
antialias_physorg
5 / 5 (1) Jan 22, 2011
Wouldn't a group of lasers powerful enough to launch a rocket simply disintegrate the spaceship before it even got off the ground?

That's the point. The lasers hit the propllant which then evaporates and the resulting explosive impulse drives the craft.

An issue would be that this leaves a plume of gas behind the craft which would disperse the followng laser shots - ut I think they should try this out with simulations/a small demonstrator
Pkunk_
1 / 5 (1) Jan 22, 2011
What a novel idea!
I wonder if we could get elephants into space with it?

Sure Gomer, why not?


Heh, guess not . But the spacecraft would look probably look like Dumbo.
Skepticus
3 / 5 (2) Jan 22, 2011
For beam power and dispersion problems, build *really* reliable, long lived beam-powered modules fitted with solar concentrators and energy conversion systems onboard with power beams projection capability, send them into low solar orbits for max energy collection by the ground arrays. Then send a second wave of beam modules further out, powered by the combined beams power from the first solar array and so on. Those arrays will have to be boosted/replaced periodically by additional modules, but it can be done gradually as resources permit. Due to energy conversions losses, it's probably like a pyramidal order, with (hundred?) thousands in the first array near the sun, less on each array further out and so on. Maybe 3 or more beams from the first array will power 1 from the second array and so on, arrays may be even halfway to the nearest stars. This way, you don't have to worry about beam the whole DeathStar-power-level from the ground.
Skepticus
3 / 5 (2) Jan 22, 2011
Cont.
Replacement modules can be made and sent from Earth, or future outposts on the Moon or Mars or the Asteroid Belts. They will get into required the required slot by sails or ion drives, powered by beam power of the existing network. Then the whole thing will be powered by the Sun, literally, to get other crafts to the stars. If a viable world is at a reasonable distance, the whole scheme can be replicated there (slowly..!) for two-way traffic.
...Unless some smartarses invented the Warp drive by then!:-))
Bog_Mire
1 / 5 (1) Jan 22, 2011
sold
plasticpower
5 / 5 (1) Jan 22, 2011
People need to get one thing out of their head: a system like this is only relevant for transfer to orbit. Beyond orbit and in deep space we have a different technology called Variable Specific Impulse Magnetoplasma Rocket that will be used to achieve speeds of 0.01c and faster. A laser system would be perfectly suited for delivering the components into orbit so they could be assembled.

We will NOT be able to make a single propulsion system that can take off from Earth and fly around the solar system. But we can have two separate systems that combined are vastly superior to the 60+ year old chemical rocket technology.
MorituriMax
1 / 5 (1) Jan 22, 2011
"Any launch system would be built in high-altitude desert areas, so danger to wildlife shouldn’t be a concern, Kare says. "

Because we all know how many airports and spaceports are build up at high altitude because it's always affordable to go uphill with trucks. How high are they talking? Get too high and I wouldn't want to work there (re observatories and thin air dangers).
rbrtwjohnson
not rated yet Jan 22, 2011
A newer alternative propulsion system that has been proposed is the phase-shifted electrodynamic propulsion which could definitively change the way of traveling in the deep space.
youtube.com/watch?v=Z8Hwqg9_oA8
ODesign
not rated yet Jan 22, 2011
Additionally, this system would only be useful for a probe on a fly-by mission, because it offers no solution for the braking phase of travel on the other end. So the craft wouldn't be able to slow down to an orbital velocity for the distant star or planet. You'd only have a one-shot fly-by, like the New Horizons spacecraft passing Pluto...

??? could you have the spacecraft use a gravity well (the sun for example) to do a slingshot maneuver and then the lasers would work to slow it down? I guess it's a question of how deep and compact a gravity well you need to do a 180 degree slingshot based on how fast the spacecraft is moving. For some speeds the distance to the center of gravity required for a 180 degree slingshot could put the spacecraft inside the suns corona or have it impact a planet.
Parsec
5 / 5 (1) Jan 22, 2011
...this system would only be useful for a probe on a fly-by mission, because it offers no solution for the braking phase of travel on the other end. So the craft wouldn't be able to slow down to an orbital velocity for the distant star or planet. You'd only have a one-shot fly-by, like the New Horizons spacecraft passing Pluto...

Th ability to place a craft into orbit or send it on its way on an interplanetary mission has no implications WHAT is being sent. There is no reason that the craft cannot contain the engine and fuel necessary for braking at the end of its flight.
holoman
1 / 5 (1) Jan 22, 2011
Why not just solve the anti-matter problem and be
done with all these band-aid solutions.
holoman
1 / 5 (1) Jan 22, 2011
A newer alternative propulsion system that has been proposed is the phase-shifted electrodynamic propulsion which could definitively change the way of traveling in the deep space.
youtube.com/watch?v=Z8Hwqg9_oA8


Nice graphics. Linear accelerator using electrons and even one that creates anti-matter from the electrons has a patent pending.

The same inventor is proposing a linear thermonuclear reactor using DD or DLi along
with space matter.

No technical information is given as I understood from their reply they are working in secret and
not interested in support from public, private or
government sources.

Sounds like they expect to leave the planet as soon
as possible.

Quantum_Conundrum
1 / 5 (1) Jan 22, 2011
The ability to place a craft into orbit or send it on its way on an interplanetary mission has no implications WHAT is being sent. There is no reason that the craft cannot contain the engine and fuel necessary for braking at the end of its flight.


you uh...realise you're talking about having a braking stage the size of the existing space shuttle...
deatopmg
1 / 5 (2) Jan 22, 2011
When this idea was floated around in the 70's's it was nicknamed the "assender".
mrlewish
not rated yet Jan 23, 2011
Why concentrate on this? The miniaturization of components gets you more bang for the buck then any possible propulsion system, at least when chemical rockets are considered. Besides the infrastructure for the lasers looks like it would be hard (expensive) to move.
Skultch
not rated yet Jan 23, 2011
Soooooo, space elevator without the cable? Got it.

Would it make more or less sense to focus solar power in space and reflect it off a mirror or store it? How long would it take a launchable solar collector to pay for itself in energy costs?
ZachB
5 / 5 (1) Jan 23, 2011
Forget that NASA study. Those guys don't do anything without a mountain of money and custom-made equipment. My guess is they report that its not viable at this time. This research study is better left to the navy.