US Cargo Missions to ISS to Resume

SpaceX Falcon rocket with Dragon cargo spacecraft at Complex SLC-40. 

The main radar installation that supports launches from both the Kennedy Space Center and the Cape Canaveral Air Force Station suffered a fire a few weeks ago. It turns out that the radar, operated by the 45th Space Wing of Patrick Air Force Base, required major surgery to repair. As a consequence, launches scheduled from the east coast of Florida were delayed. Today that delay will end, hopefully, with the launch of an Atlas V carrying a classified military satellite. Following today's launch, SpaceX will be clear to launch its Dragon cargo spacecraft to the ISS on April 14th.

Atlas V launch last Thursday from Vandenberg AFB.

Today's Altas V launch was itself dependent on a successful launch of another Atlas V mission last week from Vandenberg AFB in California. That mission, carrying an Air Force weather satellite, started a 7 day turnaround for support crew elements and a review of the launch data. Once the data had been cleared, and the support crew from the United Launch Alliance (ULA) had transferred over to  Florida to work on the launch of the new updated Atlas V 541, which can launch heavier payloads than the earlier Atlas V versions. Today's mission carries a secret spy satellite for the National Reconnaissance Office. 

Progress spacecraft approaches the ISS.

In the meantime, the glitch that occurred on the recent Russian Soyuz launch to the ISS seems not to have repeated with the launch this week of a Progress robotic cargo spacecraft to the station. Using the navigational shortcut trajectory, the Progress M-23M (P55) spacecraft successfully arrived to dock with the station after a six hour flight on Wednesday April 9th. A previous Progress spacecraft, Progress M-22M (P54), undocked from the ISS on Monday. Filled with garbage and waste, the craft will remain in orbit for 11 days while engineers on the ground conduct some final experiments, then it will burn up in the atmosphere. The current Progress is docked at the Russian-built Pirs module.