What happened

Shares of space tourism pioneer Virgin Galactic (SPCE 2.73%) took off like (what else?) a rocket on Tuesday, soaring 24.5% through 12:30 p.m. ET.

It's not hard to see why.

So what

As soon as one week from now, a local newspaper reported, Virgin Galactic will conduct its first-ever paid space tourism flight, carrying a team of three Italian Air Force passengers to the edge of space. The window for this historic flight opens on June 27. And even if for some reason the flight cannot take place on that date, the company will have several more chances to make the flight as the window remains open through June 30.

Air travel website The Points Guy confirms that the three tickets for this flight sold for $200,000 each. Thus, this inaugural commercial spaceflight should net Virgin Galactic a cool $600,000 in revenue -- more revenue than it collected in five of its last eight quarters, according to data from S&P Global Market Intelligence.

What's more, this flight will set the stage for Virgin Galactic to collect even more revenue in the months and quarters to come. To date, the company has sold 600 tickets at prices ranging from $200,000 to $250,000, before switching to a new pricing scheme that jacked prices to as high as $450,000.

Now what

That right there poses a bit of a problem for Virgin Galactic: Before it can start carrying space tourists for $450,000, it must first honor the prices quoted to some 600 tourists who are paying roughly half that price.

Even maxed out at six passengers per flight, the old top rate of $250,000 implies Virgin Galactic must fly at least 100 times making no more than $1.5 million per flight before it can start yielding $2.7 million per flight.

And with even the optimistic forecasts saying Virgin Galactic might fly only once per month after commercial operations have begun, it could take as long as eight years for the company to work through the backlog of cheaper tickets already sold. Unless it gets more spaceplanes built and starts flying them more frequently -- all of which will cost money.

That's eight long years making no more than $18 million in revenue for a space tourism company that incurred more than $500 million in operating costs last year.

Although I agree that Virgin Galactic is giving its investors something to cheer about this week -- and I hope for more good news next week -- I wouldn't cheer too loudly just yet. Unless and until the company finds a way to cover its costs better, this stock remains speculative at best.