Boeing’s CST-100 Starliner is integrated on top of United Launch Alliance’s Atlas V rocket at Cape Canaveral Space Force Station. Various tests have been completed to ensure all systems between the rocket and spacecraft are communicating and functioning properly before roll to the pad.

Teams conducted numerous checks, including a power up of the spacecraft’s avionics system, health checks of the batteries, propulsion system, ordinance system and data flight instrumentation (DFI). Teams also performed interior/exterior inspections, and side hatch leak testing. To date, frequent cycling of the oxidizer isolation valves has been successful in showing repeated valve performance.

Tracking and Data Relay Satellite (TDRS) testing also took place to confirm telemetry and command capability between the launch vehicle and spacecraft and Starliner Mission Control in Houston.

Final standard prelaunch preparations include loading “late stow” cargo at the launch pad, a final software Mission Data Load with standard prelaunch updates for relative navigation, space weather, inertial navigation and propellant quantities.

The integrated stack is set to roll out to the pad at Space Launch Complex-41 at 10:00 a.m. ET on Wednesday, May 18, for the Orbital Flight Test-2 (OFT-2) set to launch Thursday, May 19, at 6:54 p.m. ET.

-ULA photos Scott Schilke /