Cygnus space truck arrives to ISS safe and sound despite engine failure

Today at 10:11 Moscow time, Northrop Grumman’s Cygnus cargo spacecraft arrived at the International Space Station, delivering almost 4 tons of payload. This was the ISS supply mission’s 21st flight. Shortly after entering space, the ship was unable to start its engines, which could have prevented the delivery of valuable cargo. But everything worked out.

The Cygnus truck is captured by the ISS robotic arm. Image source: NASA

As NASA previously reported, after the spacecraft separated from the upper stage of the SpaceX Falcon 9 launch vehicle, the critical moment of starting the ship’s own engine was missed, causing Cygnus to hang in an intermediate orbit. An attempt to start the engine after 50 minutes was rejected due to low pressure in the system, Northrop Grumman engineers explained. But soon the pressure in the system was found to be sufficient to try to start the engine and deliver the cargo ship to the ISS.

To complete the maneuver to approach the station, the truck’s engines were started twice. At 10:11 (at 03:11 local MCC time), a robotic arm at the station captured the truck and ensured its docking with a free airlock. The valuable cargo arrived safely at the station, where, by chance, there were two more crew members than usual.

On board Cygnus, 3857 kg of cargo was delivered to the station, including 1560 kg of equipment, 1220 kg of materials for scientific research, as well as 1021 kg of crew supplies. As NASA previously said, the equipment includes “critical spare parts and new equipment,” which also includes biomaterials for studying the effects of space on the DNA of microorganisms and an experiment to study stem cells that could be used in the future to treat blood diseases.