Sierra Space’s “mini shuttle” Dream Chaser space plane may make its maiden flight in May after launching atop a rocket from Cape Canaveral Space Force Station. Pre-flight testing continues at NASA’s Kennedy Space Center. Wednesday, Sierra Space officials announced the spacecraft successfully completed and passed another round of test milestones in collaboration with NASA . The test demonstrated Dream Chaser’s “ability to power-on, air-cool, and exchange data with multiple powered payloads inside its pressurized cabin,” a press release said. The company’s latest launch target: no earlier than May , company spokesperson Alex Walker said. The 30-foot-long Dream Chaser, which…..