SpaceX president and CEO Elon Musk announced on April 25 that the company plans to protest the Air Force's five-year, block-buy of 36 Evolved Expendable Launch Vehicle rocket boosters from the United Launch Alliance -- a deal that was signed last December. The Air Force has for years relied solely on ULA's Atlas V and Delta IV launch vehicles to send its medium-class spacecraft into orbit. And while it has recently created a process by which interested competitors may become...