SPACEFLIGHT GAP IS BIGGEST NASA CHALLENGE: "The most distressing challenge for NASA ... is the looming gap in human spaceflight that will be created once the shuttles are no longer available to fly NASA astronauts to the International Space Station." You don’t say. Read it all, especially former NASA administrator Michael Griffin’s comment that the government should retain some capability even after commercial human spaceflight becomes extant. Griffen’s loss was a huge blow to NASA.