What happened

Two months ago, Sir Richard Branson's Virgin Orbit tried to fly an airplane to altitude, drop a space rocket from its wing, and then blast it into orbit. The test failed. After deploying from its Cosmic Girl mothership, the rocket ignited and began heading to space, but then it suddenly lost power and had to be destroyed.

Yesterday, the satellite-launching company told a group of space professionals gathered to attend a webinar held by the Space Generation Advisory Council that it has figured out what went wrong with its rocket: "We had a component break in our engine system. It was a high-pressure feed line." The company says it can now proceed to fix the problem and try again later this year.

Shares of Virgin Galactic (SPCE 1.59%) leapt in response to the news today, rising 7% through 11:40 a.m. EDT. There's just one problem with that, though ...

Virgin Galactic is not Virgin Orbit.

Virgin Galactic's VSS Unity blasting into space

This is Virgin Galactic. Image source: Virgin Galactic.

So what

In fact, aside from Virgin.com Limited owning a lot of stock in Virgin Galactic, and owning all of Virgin Orbit, the two companies have no direct relation to each other. They're "sister companies," nothing more. That being the case, it doesn't make much sense for investors to be buying shares of Virgin Galactic just because Virgin Orbit had some good news -- but there you go.

Absent any other news that might be pushing Virgin Galactic stock higher today, this appears to be our best working theory for why the space tourism company's stock is going up. (If, that is to say, there is any reason at all.)

Virgin Orbit's Cosmic Girl deploying a LauncherOne rocket

This is Virgin Orbit. Image source: Virgin Orbit.

Now what

If this is in fact the reason Virgin Galactic stock is up today, I'd expect its gains to be fleeting and for the stock to fall back down again once investors realize their mistake. On the other hand, if this is just another of those wobbles that we see from time to time in Virgin Galactic's valuation, then there's nothing to prevent the stock from just continuing on higher.

One way or another, we should know what happened by tomorrow -- or even later today.