Video: Falcon 9 rocket fires engines in pre-launch test (members only)

Russian launch crews stood up a Soyuz rocket Sunday on its launch mount in Kazakhstan for a scheduled liftoff Wednesday with approximately 5,500 pounds of supplies, experiments, fuel and several small satellites to be released by spacewalking cosmonauts at the International Space Station later this year.

SpaceX is still working on a new, safer helium tank design needed for launches with astronauts, and the debut of the company’s upgraded Falcon 9 Block 5 rocket earlier this month did not count as one of seven successful missions in “crew configuration” NASA says it requires before putting astronauts aboard the vehicle, officials said Thursday.

SpaceX scrubbed a launch attempt early Wednesday at Cape Canaveral due to thick cloud cover, then delayed the liftoff of a Falcon 9 rocket with an Airbus-built communications satellite for Arabsat until Friday night to wait for improved weather and to make room for the test-firing of United Launch Alliance’s Vulcan rocket at a neighboring launch pad.