The world's first private, manned spaceship — Virgin Galactic's SpaceShipTwo — completed its first test flight on Sunday, a crucial step toward making commercial space tourism a reality. The craft, also known as the VSS Enterprise, has more tests to pass before it can carry its first paying passengers into suborbital flight. In this one, a mother ship carried SpaceShipTwo aloft and released it over the Mojave Desert, after which SpaceShipTwo glided down without firing the rocket that will propel it into space. (Watch Richard Branson discuss his innovation.) Here's a look at the numbers behind this feat of aerospace engineering:

45,000 feet
Altitude SpaceShipTwo reached during this test flight

50,000 feet
Altitude SpaceShipTwo will reach with space tourists before its rocket fires up

2,500 mph 
Speed SpaceShipTwo will attain under rocket power

316,000 feet
Altitude SpaceShipTwo will reach with tourists on board — around 60 miles above the surface of the Earth

The cost of a ticket on SpaceShipTwo. A $20,000 deposit is required

Number of passengers who have already paid their deposits

180 minutes
Length of proposed SpaceShipTwo flights. Passengers will experience around five minutes of weightlessness

Number of passengers SpaceShipTwo will carry on each flight, along with two pilots

Number of SpaceShipTwo planes proposed for Virgin's fleet

$400 million
Cost of the five commercial spaceships and launch vehicles

60 feet
Length of the SpaceShipTwo

122 feet
Length of the Space Shuttle Endeavour

18 months
Length of the testing process for SpaceShipTwo

The year in which Virgin hopes to begin commercial flights into space


Years from the publication of 2001: A Space Odyssey to the dawn of actual commercial spaceflight

Sources: Virgin Galactic, Yahoo News, National Geographic, Los Angeles Times, USA Today