NASA will host a media briefing at 11 a.m. EDT Thursday, April 28, at the Kennedy Space Center in Florida to highlight the four companies selected for the second round of the agency’s Commercial Crew Development (CCDev2) efforts.

The briefing is part of the countdown activities for the final scheduled launch of space shuttle Endeavour’s STS-134 mission to the International Space Station. Lift off is scheduled for 3:47 p.m. on Friday, April 29.

The news conference participants are: — Phil McAlister, acting director, Commercial Spaceflight Development, NASA Headquarters, Washington — Ed Mango, program manager for NASA’s Commercial Crew Program, Kennedy Space Center — Rob Meyerson, program manager, Blue Origin, Kent, Wash. — Mark Sirangelo, program manager, Sierra Nevada, Louisville, Colo. — Garrett Reisman, program manager, SpaceX, Hawthorne, Calif. — John Elbon, program manager, The Boeing Company, Houston

On April 18, NASA awarded $269.3 million to these companies to accelerate the availability of U.S. commercial crew transportation capabilities and reduce the gap in American human spaceflight capability. Through this activity, NASA also may be able to spur economic growth as potential new space markets are created. Once developed, crew transportation capabilities could become available to commercial and government customers.

The briefing will be broadcast live on NASA Television and streamed at: http://www.nasa.gov/ntv

The NASA News Twitter feed will be updated throughout the shuttle launch countdown, mission and landing. To follow, visit: http://www.twitter.com/nasa

Kennedy manages the agency’s Commercial Crew Development efforts for the NASA’s Exploration Systems Mission Directorate. http://www.nasa.gov/exploration