Laser-powered rockets could be our pipeline to outer space

Illustration for article titled Laser-powered rockets could be our pipeline to outer space

It's an awesome solution to a simple problem: you need ridiculous amounts of fuel to get a rocket into orbit. However, if the rocket fuel was considerably hotter, it would be more energetic, and you'd need way less fuel to launch the rocket. So why don't we just shoot powerful lasers at rockets? It's so insane that it just might work.


It's hard to underestimate just how much fuel you need to lift a rocket into orbit - generally speaking, 97% of any conventional rocket is taken up with just the fuel and the tanks, leaving almost no room at all for payloads or astronauts. But if the fuel was spiked with a laser to temperatures around 3,100 degrees Fahrenheit...well, then you'd need a fraction of the fuel to achieve the same ends.

Now, there are some stumbling blocks here, although the technology is pretty much already in place. To make this at all financially viable, there would need to be thousands of launches per year, and payloads would still be limited to just over 200 pounds. That means this wouldn't really be an option for any crewed missions or for any heavy-duty, sophisticated equipment.

But that doesn't necessarily have to matter, as larger spacecraft could then be assembled in space from the parts brought up by the laser rockets. These rockets would be like a pipeline funneling materials from ground to space so that larger ships can be built or repaired. It's essentially shifting where we launch complex missions into orbit, with the ground simply becoming part of the supply chain.

Physicist Jordan Kare says the system has other advantages as well:

"Some alternatives to conventional launchers really are highly desirable. It may be time to at least do some development work to see if this is at least potential...The notion of the rocket where engines can be working but avionics fails doesn't exist. It can't go anywhere the laser isn't pointed. And it can't explode in the way that rockets occasionally do. There just isn't the energy onboard. Also, because it's high rate launch system, you can do far more testing than you can on any other system. You can launch thousands of times before you launch a person or a high-value payload."

Via Discovery News.



Wait. I'm no fancy-shmancy physicist, but am I wrong in assuming that acceleration that allows a rocket to go to space comes from mass expulsion? How would hotter fuel aid this process? The energy expelled comes from the breaking of bonds (I assume) - hotter fuel would just break those bonds faster. The acceleration in the beginning might be quicker, but peter out at an equally accelerated rate. Someone smarter than me explain this quandary.

EDIT: I reread it again, and I'm still not getting it. "If the fuel was hotter, it would be more energetic." All that means is that it burns out more quickly, right? The next energy release would still be the same, no?