U.S. commercial cargo ship delivery mission ends as Canadarm2 releases Cygnus

Expedition 40 Flight Engineers Alexander Gerst and Reid Wiseman were inside the cupola remotely controlling the 58-foot Canadian robotic arm from the robotics workstation. Gerst, who was backed up by Wiseman, was in charge of releasing the resupply vehicle after ground controllers at Mission Control, Houston remotely maneuvered it into the release position following its unberthing from the Earth-facing port of the Harmony module.

Filled with trash, Cygnus completed its second commercial resupply mission for NASA. Orbital Sciences launched their spacecraft July 13 atop an Antares rocket from the Mid-Atlantic Regional Spaceport at the Wallops Flight Facility, Virginia on a three-day journey to the orbital laboratory. A total of eight missions will be flown by Cygnus to the station through 2016.

Cygnus delivered nearly 3,300 pounds of science, supplies and spacewalking gear when it was captured and berthed to Harmony July 16. Aboard the spacecraft were items such as food, life support equipment, thermal control hardware and photography and video gear.

Experiment hardware was also on the Cygnus manifest ensuring the continuous international research aboard the orbital laboratory.

A flock of nanosatellites was also shipped to the station aboard Cygnus for future release from the Kibo laboratory module's airlock beginning next week. Individually known as "Dove" satellites, the group will collect continuous Earth imagery documenting natural and man-made conditions of the environment to improve disaster relief and increase agricultural yields.

Hardware upgrades were brought up to the station on the ship for a trio of tiny satellites that float inside the station known as SPHERES (Synchronized Position Hold, Engage, Reorient, Experimental Satellites). Gear enabling studies for educators, students and private researchers was also delivered for the NanoRacks program in a partnership with NASA under the Space Act Agreement.

The Expedition 40 crewmembers hope to document Cygnus' reentry Sunday as part of an engineering exercise to study the mechanics of the breakup of a space vehicle. Cygnus is scheduled to deorbit Sunday around 8:30 a.m. EDT.

With the Cygnus private cargo carrier orbiting a safe distance from the station the crew is conducting science and maintenance and focusing its attention on a Russian spacewalk Monday morning.

After completing the robotics work to release Cygnus, European astronaut Alexander Gerst switched gears and spent a couple of hours on plumbing work. He replaced a pre-treat tank and hose in the Tranquility node's Waste and Hygiene compartment.

Meanwhile, Commander Steve Swanson and Flight Engineer Reid Wiseman participated in the SPHERES-Zero-Robotics student competition. Middle school students compete to write the best algorithm to maneuver bowling ball-sized internal satellites through various tasks inside the space station.

The station's cosmonauts had an off-duty day in the Russian segment of the orbital laboratory while still performing some tasks. The trio conducted light housekeeping work, health and science checks and minor preparations for the upcoming spacewalk.

Flight Engineers Alexander Skvortsov and Oleg Artemyev plan to exit the Pirs docking compartment at 10 am Monday to deploy a Peruvian CubeSat, retrieve old experiments and install new ones, among other external tasks.

In the meantime, Skvortsov conducted a hearing assessment. Artemyev checked in with spacewalk specialists on the ground for a tag up. And Flight Engineer Max Suraev photographed the condition of air ducts in the Zvezda service module.