Today is Memorial Day. As you enjoy your holiday, please take a moment to reflect on all the men and women who made the ultimate sacrifice in defense of the liberty we treasure.

NASA's statement:

Space Station Crew's Memorial Day Message
Aboard the International Space Station, Expedition Two Flight Engineers Susan Helms and Jim Voss provide their insights into the significance of Memorial Day to the International Space Station as well as to all Americans on Earth. Susan Helms, a Colonel in the U.S. Air Force, describes the importance of “military service in maintaining our freedom and preserving all those values that we Americans hold dear.” Jim Voss, a retired U.S. Army Colonel, adds that no holiday affects us as deeply as Memorial Day, as we "pause and remember those who made the ultimate sacrifice...and...salute the commitment and dedication of those who carry on their legacy, proudly defending our freedom into the 21st century."

NASA has chosen 22 contractors for the first phase of their Space Launch Initiative, the plan for the next-generation manned spacecraft.

Will film-maker Jim Cameron be the next space tourist?

Today In Space History - Forty years ago today, the first American astronaut blasted into space. Alan Shepard became the first space explorer for NASA when his Mercury capsule, "Freedom 7," was lofted into a suborbital flight atop a Redstone rocket on 5 May 1961. NASA explains:

NASA Celebrates 40 Years of Human Space Flight
On May 5, 1961, the United States took a giant step into the future when Alan B. Shepard, Jr., became the first US Astronaut. His 15-minute, sub-orbital flight ushered in a new era for Americans, one in which they came to view themselves, the Earth and the Universe in fresh, new ways. On Tuesday, May 8, 2001, NASA, in collaboration with the Space Policy Institute at The George Washington University, Washington, DC, will sponsor a one-day symposium to commemorate the 40th anniversary of human space flight. The conference, "Looking Backward, Looking Forward," will reflect on the significance of human space flight to American society over the past 40 years and its likely role over the next four decades and beyond. Attendance is free. The conference will be broadcast on NASA Television. Follow the link for more about Shepard's historic flight.

Shepard would walk on the Moon 10 years later, as part of Apollo 14. He retired from NASA in 1974, and lived until 1998, when he lost his battle with leukemia. Here's to many more decades of adventure! [Date: NASA]