The major players in the suborbital space flight world gathered for a panel at the FAA/AST Commercial Space Transportation Conference in Washington this week. They brought a standing room only audience up to date on their progress so far in developing frequent, safe exoatmospheric flight services to private and government markets.

The field of reusable suborbital flight was pioneered by the X-15 rocket plane in the 1950s and 1960s and not picked up again until SpaceShipOne breached the atmosphere in 2004. Now a cadre of startups is at work moving the field from experimental flight to regularly scheduled service for researchers and space adventurers.

It’s an easier challenge than orbital flight, which requires speeds at 25 times the speed of sound (SpaceShipOne went “just” 3 times the speed of sound), but it’s still a challenging problem. When asked to name the top three challenges to pulling this off as a business, Armadillo Aerospace’s Neil Milburn quipped “takeoff, climb, and landing.”

The other panelists were George Whitesides of Virgin Galactic (bankrolling SpaceShipTwo); Colin Ake of Masten Space Systems; and Jeff Greason of XCOR Aerospace.

Click the play button on the pencast above, and then wait for the audio to finish downloading to hear the complete panel discussion. Click anywhere in my handwritten notes to jump to that part of the audio. Highlights include Milburn’s description of Armadillo’s manned flight plans (one passenger on a remotely piloted vehicle) and Greason’s plea for patience as the industry matures at its own pace (during the Q & A section).