THREE REASONS THIS ROCKET WON’T SEND US TO MARS

Ever been to the website Elite Daily?  If you haven’t, don’t bother.  Home of such journalistic masterpieces as “Zayn Malik Isn’t Worried About Leaving One Direction Because His Fiance Is Hot As F*ck” and “Man Given 18 Months To Live Says Cannabis Oil Cured His Cancer,” it’s a long-running stream of feel-good drivel that’s generally harmless.  Sometimes they veer out of the world of hot-button cultural issues like “Starbucks Is Coming Out With A S’mores Frappuccino In Time For Summer” and into the realm of science.  Like this headline here.

Screen Shot 2015-04-19 at 9.02.24 PM

Turns out they should have stayed in their lane.

1. This rocket doesn’t exist

I mean, it really really doesn’t exist.  The rocket hasn’t been built.  The engine to power it hasn’t been built.  The engine to power it hasn’t actually been invented.  The technology to power the engine that doesn’t exist to put inside the rocket that doesn’t exist?  Yeah, that doesn’t exist either.

The engine is powered by something called a Variable Specific Impulse Magnetoplasma Rocket, which you may not have heard of because it doesn’t exist.  In theory, it works by using a nuclear reactor to generate electricity, which then creates radio waves to ionize and heat a propellant, and magnetic fields to accelerate the resulting plasma to generate thrust.  In theoryit’s way more efficient than traditional rocketry.  In reality, it doesn’t exist.

Oh sure, we can use electricity to create plasma and then use magnets to accelerate it, but that’s on test engines that are plugged into the grid.  This one’s in space, where there are no plugs.

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In space, no one can hear your phone die…

That means we have to bring a nuclear reactor along, and that’s a problem.  You see, nuclear reactors are big.  Really, really big.  Here’s one called an S6W, which is used to power the Seawolf class nuclear fast attack submarine.

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I used that as an example because it goes in a fast attack submarine.  That means that it’s about as compact as it’s possible to make a nuclear reactor, and that particular model can generate about 34 megawatts of power.  This hypothetical spaceship engine would need 200 megawatts.  That means that, in the words of one critic, this hypothetical spaceship would need “nuclear electric power systems with 10,000 times the power and 1/100th the mass per unit power as any that have ever been built.”  What that means is that this rocket could totally get us to Mars in six weeks,

if we could magically make nuclear power one million times more efficient.

Which we can’t.  If we could do that, one normal sized nuclear power plant could power the entire planet three or four times over.  That’s the level of ridiculousness we’re talking about here.  It’s the equivalent of running a car for its entire lifetime on one and a half cups of gasoline.  And just as gasoline is physically incapable of generating that much energy, so too is uranium-238.

It is not possible, on a physical, subatomic level, to get that much power out of uranium.  This engine cannot be built.

2. If we could build it, we couldn’t cool it

I showed you the submarine engine because it’s very compact, and the reason it’s so compact is that it has the added benefit of not needing much cooling infrastructure because it’s in the ocean literally all the time.  Nuclear reactors need a LOT of cooling.  Most of them are located next to water, like a river or the ocean, and they use that to cool down.  Those that don’t have water nearby use massive cooling towers.  Some use both.

That's what these are.
That’s what these are.

In space, there’s no water.  There’s not even air.  The only way to cool things down is by letting heat radiate into space, and that usually means some sort of heat sink.  Astronauts in space don’t get cold, they overheat.  But the amount of heat put off by a 200Mw nuclear reactor is a completely different ball game from the heat put out by a person, and none of our current technologies are useful.

3. It can’t take off.

Dr. Franklin Chang-Diaz says himself, “The VASIMR engine is not used for launching things into space or landing them back but rather it is used for things already there.”  That means that this whole thing will have to be built on Earth, put in space by rockets, assembled in space, and then set off from there.  That’s not that big a deal.  We at least have the technology to build stuff in space, and we’ve done it before.  But at the Mars end, this thing will have to use normal rockets to get down to the surface and back, carrying the crew and whatever equipment they bring.  That means more weight, fuel, etc.

So, to sum up:

  • If we can invent a nuclear power system that’s vastly more efficient than any form of power generator the world has ever seen, and
  • if we can discover some heretofore nonexistent material to vent the stupendous quantities of heat into space, and
  • if we can build this whole thing in space,

Then we can totally go to Mars in six weeks.

I’ll be right over here on the edge of my seat.

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