The following is by astronauts Buzz Aldrin, Ken Bowersox, Jake Garn, Robert Gibson, Hank Hartsfield, John Herrington, Byron Lichtenberg, John Lounge, Rick Searfoss, Norman Thagard, Kathryn Thornton, Jim Voss and Charles Walker:

As crew members who have flown aboard spacecraft such as America's Space Shuttle and the International Space Station, we know that exploring space is a worthwhile and challenging endeavor. Increased use of public-private partnerships—where commercial companies assume a larger...