It was truly a show to see.

Last Sunday, SpaceX blasted off the latest in a seemingly unceasing stream of Falcon 9 rockets, this time with a Crew Dragon space capsule at the tip. About 90 seconds into the flight, that capsule fired off an octet of its own rockets -- SuperDraco thrusters -- blasting itself clear of the rocket main body.

Ten seconds later, that rocket main body blew up -- on purpose.  

Artist's rendering of SpaceX Crew Dragon during its docking with ISS

Image source: SpaceX.

Once more, with feeling

Sunday's test flight marked a redemptive moment for SpaceX. Just nine months earlier, the company had suffered the heartbreak of seeing its experimental "Crew Dragon" spaceship, which had successfully flown to the International Space Station and back in March, explode on a ground stand during an engine abort test preparatory to a second flight.

That unexpected "anomaly" delayed SpaceX's planned next mission to ISS -- "Demo-2" -- in which SpaceX planned to send a pair of astronauts aboard a Crew Dragon to the space station last year.

But with its success in the even more complex and high stakes in-flight abort test -- which tested the same engines' performance, but mid-air -- SpaceX is now back on track, and once again progressing toward its goal of becoming the first company to launch American astronauts into space since the Space Shuttle program was shut down in 2011.

Beating Boeing

Flying astronauts to the ISS is currently a two-horse race and has been ever since NASA awarded both SpaceX and Boeing (BA -1.83%) twin "commercial crew" contracts back in 2014.

But here's the curious thing about this space race. Back in 2014, NASA hired both SpaceX and Boeing to perform essentially the same tasks: To develop a spacecraft capable of safely transporting astronauts to ISS and back, to flight-test that spacecraft, and, assuming all went well, to perform "at least two, and as many as six, crewed missions to the space station" (each) over a period of years.

In compensation for this work, NASA agreed to pay SpaceX $2.6 billion -- and to pay Boeing $4.2 billion.

Now, both these figures have since increased. At last report, SpaceX is expected to earn closer to $3.1 billion for its work on the commercial crew program -- and Boeing $5.1 billion. But one fact remains the same:

For performing essentially the same job SpaceX has, Boeing is being paid more than 60% more money.

Even more intriguing

And this is curious. Granted, back in 2014, NASA might have been willing to pay Boeing a premium for its superior track record of reliability. At the time, Boeing (or more precisely, the United Launch Alliance joint venture it shares with Lockheed Martin) had by far the better track record, scoring 100% mission success over a stretch of nearly 100 consecutive launches, whereas SpaceX had only launched a handful of times.  

But today, the situation almost looks reversed.  Through mid-January, SpaceX has now racked up an impressive reliability record of its own -- 51 straight successful launches, and nearly as many rocket landings (a feat no other company on Earth has managed to match).

In contrast, while ULA has upped its record of successful rocket launches to 136, Boeing's Starliner spacecraft whiffed on a key test last month, when it missed its insertion target, and failed to rendezvous with the space station.  

As a result, today, it kind of looks like NASA is actually paying Boeing more money for worse results than what SpaceX is producing.

The upshot for investors

Granted, Boeing still plans to get itself back on track. It's not yet certain whether NASA will require Boeing to redo its unmanned Starliner test flight before proceeding to a crewed attempt, which would delay the latter. But I'd bet money that Boeing will fix its problems -- eventually. Starliner may end up reaching ISS months, or even years after SpaceX's arrival -- but it'll get there.

The more important question for investors is whether by the time Boeing does arrive, its slowness (relative to SpaceX) will be so embarrassingly obvious that NASA must refuse paying Boeing a premium for future space missions. When you consider that Boeing's space business ("defense, space & security") is already by far the least profitable of Boeing's three main business divisions (earning operating profit margins of less than 7%, according to data from S&P Global Market Intelligence), I suspect Boeing could ill afford the loss of any premium payments NASA is throwing its way.

Conceivably, if things keep going the way they're going, and SpaceX widens its lead over Boeing in the commercial crew space race, Boeing might even decide to exit the space business entirely, rather than limp along in second place.

Mind you, I don't personally expect this to happen. Even a 7% profit margin is still something, and so long as Boeing's space division remains at least somewhat profitable, there's no immediate need to toss it out the airlock (so to speak). But it's a possibility -- and one that bears watching for anyone invested in Boeing stock.