The most recent numbers are pie in the sky: private seats on flights to the International Space Station for $30 million each, NASA contracts worth $500 million, a tourism business pegged to reach $1 billion by 2020. As cowboy entrepreneurs like PayPal co-founder Elon Musk and Amazon C.E.O. Jeff Bezos angle for a piece of the action, they are making headlines. But beyond the hype, who's really launching rockets, who's exploding them, and who is just burning through cash?

Robert Bigelow
Founder, Budget Suites of America
Company: Bigelow Aerospace
What it makes: Orbiting habitats
His investment: $100 million
Main project: A garbage-truck-size room (28.5 feet by 20.6 feet) that floats in space and can house three people.
Progress so far: Bigelow has launched two small-scale habitats (14 feet by 8 feet), which are now circling 340 miles above the Earth.
One problem: Bigelow has been unable to find cheap space vehicles that can bring people to his habitats.
Objective: To launch a habitat in 2010 and open it up for regular use in 2012.
How risky: ****

Jeff Bezos
C.E.O., Amazon 
Company: Blue Origin
What it makes: Rockets and spacecraft
His investment: Undisclosed
Main project: A vertical-takeoff, vertical-landing spacecraft that can put astronauts into suborbit.
Progress so far: Bezos bought 165,000 acres near Van Horn, Texas, in 2005 to build a launch site.
One problem: High winds during the first test launch forced a rescheduling and disappointed friends and family.
Objective: To conduct 52 launches in 2010.
How risky: **

Elon Musk
Co-founder, PayPal
Company: SpaceX
What it makes: Rockets and spacecraft
His investment: More than $100 million
Main projects: A lower-Earth-orbit rocket and a manned space vehicle.
Progress so far: In 2006, SpaceX beat out Boeing and Lockheed Martin for a $278 million NASA contract.
One problem: SpaceX hasn't successfully launched a rocket.
Objective: To test one rocket in 2008 and launch another commercially in 2010.
How risky: ****

Richard Branson Chairman, Virgin Group
Companies: Virgin Galactic and the Spaceship Co.
What they do: Space tourism and ship design
His investment: $200 million
Main project: SpaceShipTwo, a passenger ship designed to travel in suborbit. Microsoft co-founder Paul Allen gave about $20 million to help finance an early version.
Progress so far: About 230 people (including Elon Musk) have paid $20,000 each to reserve spots on future flights. Another 270 seats are still available.
One problem: An explosion during a rocket test in July killed three people.
Objective: To offer passenger flights by late 2009.
How risky: ***

John Carmack Co-founder of ID Software, maker of the videogame Doom
Company: Armadillo Aerospace
What it makes: Rockets and spacecraft
His investment: More than $3 million
Main project: A rocket and spacecraft for suborbital flight.
Progress so far: Armadillo was the only company to fly in the 2007 Lunar Lander Challenge, sponsored by Northrup Grumman.
One problem: The Armadillo rocket, Texel, burst into flames and crash-landed during a test in August 2007.
Objective: To have a viable launch vehicle in the next several years.
How risky: **