Mars By Light?

(Video screenshot by Michael Franco/CNET)

According to Michael Franco at CNET, NASA is giving serious consideration to a technology that could get spaceships to Mars in a few days instead of months and years. Citing work by professor Philip Lubin at UC Santa Barbara, he says it should be possible to push a spacecraft into deep space using the power of light. Lasers to be precise. The ship would have to be wafer thin, so it acted like a sail, but after that, the only issue is finding a big enough laser. Apparently,

"using the same amount of time (10 minutes) and chemical energy (50-100 gigawatts) it will take to get the Space Launch System (SLS) into orbit, his proposed system could propel a craft to 30 percent the speed of light -- getting a 100-kilogram (about 220-pound) robotic craft to Mars in just a few days. The SLS is the world's most powerful rocket, now being developed by NASA for an eventual manned mission to Mars."

Now, to be fair to Prof. Lubin, I doubt he is actually proposing a Mars Mission like that, because, if he was, he would be cray-cray - and not in a good way.

What that example entails is accelerating a spacecraft from zero to roughly 56,000 miles a second in 600 seconds. If my high school physics hasn't deserted me, that's like 15,000g!!!!

Think of it this way. If you were lying in bed, looking up at the ceiling, and your home was accelerated away at 15,000g, your eyeballs would weigh about 470 pounds! Things would get real squishy, real fast.

And even if a spacecraft could survive an acceleration like that, it's traveling at 200 million miles an hour... and it can't stop! How are you going to take pictures or do anything else when you get there? Mars is about 4,000 miles across, so you'd pass the entire planet in about seven hundredths of a second. Bad idea!!!!

On the other hand, what if you had kindler, gentler lasers at both ends? An Earth laser to get you up to speed, and a Mars laser to slow you down. You could still get there in a few weeks, slow down enough to enter orbit, do what needs to be done and, hopefully, come back home again. Hmmmm. Maybe, somewhere in all that, there's a novel!