SpaceX Dragon Launch May Be Delayed Again Over ISS Power Glitch

A malfunction on an electrical distribution unit at the International Space Station may prompt NASA to delay the launch of SpaceX Dragon cargo mission ship scheduled for Wednesday, May 1.

The cargo was expected to be received by the ISS early Friday. The lab’s robot arm will be responsible to lock in the cargo and pull it in for berthing.

“Monday morning, teams identified an issue with the International Space Station’s electrical power system and are working to identify the root cause and restore full power to the system,” an official NASA post read. “There are no immediate concerns for the crew or the station.”

This morning, an issue with the @Space_Station’s electrical power system was identified. Teams are working to identify the cause and restore full power to the system. There are no immediate concerns for the crew or the station. More details: https://t.co/Hl9Htocybx pic.twitter.com/y9AdQRYjN5
— NASA (@NASA) April 29, 2019

NASA and SpaceX originally scheduled the launch of the Dragon cargo on April 26, which had been moved from Tuesday, April 20 due to the station and orbital mechanics.

However, one of the two circuits for power source responsible for the robotic arm controls was knocked out by the main bus switching unit (MBSU) problem that was identified Monday. This led NASA and SpaceX to decide to delay the Dragon cargo for another 24 hours, making Wednesday, May 1 the final schedule.

Excited for Wednesday’s SpaceX cargo launch? We don’t blame you! This mission will support dozens of the 250+ science experiments on board the @Space_Station. Hear the latest pre-launch updates Tuesday at 1pm ET: https://t.co/RyOAur1jpJ pic.twitter.com/JO9E9209Vr
— NASA (@NASA) April 30, 2019

Based on NASA flight protocols, two power sources are required for redundancy in robotic arm operations. If the second power cannot be restored or re-routed, there will be another delay for the Dragon cargo launch until the MBSU problem is solved.

“An issue is being worked with a Main Bus Switching Unit (MBSU) that distributes electrical power to two of the eight power channels on the station,” NASA wrote in a post. “Flight controllers have been working to route power through the remaining six power channels.”

These power channels are charged up by the electrical power generated by the solar arrays of the station. NASA and SpaceX officials are already discussing to determine any impacts to SpaceX’s 17th Dragon cargo resupply mission scheduled for launch on May 1 at 3:59 a.m. EST.

The SpaceX Dragon cargo will be transporting the 5,500 pounds (2,495 kilograms) of deliveries for the ISS crew, along with its Dragon spacecraft. Deliveries will be composed of fresh supplies, experiment hardware and other gears for the Expedition 59 crew.

ThecDragon cargo will be encapsulated atop of the SpaceX’s Falcon 9 rocket at the Cape Canaveral Air Force Station. Astronaut David Saint-Jacques will be at the controls of the robotics workstation Saturday, commanding the robotic arm to capture Dragon. NASA TV will broadcast the launch and capture activities live.