Orbital ATK could be proud of their Cygnus spacecraft. After resupply mission and undocking from ISS, it performed successfully various tasks including controlled fire experiment inside its trunk.
Cygnus OA-6 “Rick Husband” spent on orbit last three months (since March 26, 2016) being docked to Unity module berthing port. After undocking performed on June 15, 2016, it started its additional tasks (main objective was of course delivering to ISS 3400 kg of supplies). First of all it took from ISS 2200 kg of disposable equipment and trash. Next, it deployed five Cubesat satellites from Nanoracks deploying device on June 20 2016. It is worth to mention that for the first time returning robotic cargo vehicle deployed satellites from Nanoracks device. Deployed satellites belonged to Lemur-2 constellation navigation and weather satellites. Just before reentry of Cygnus, Reentry Breakup Recorder (REBR) started to record sounds, register temperature data and other flight parameters using various sensors installed in different places of Cygnus. As it can be easily spotted, mission OA-6 was not limited only to delivering cargo, but it was extended for different experiments and tasks. Still, it was not mentioned that Cygnus had another important objective after undocking. In spite of 2200 kg of trash, it took from ISS very special scientific device called Saffire. It is NASA experiment which had crucial meaning for future manned space missions. Spacecraft Fire Experiment (Saffire) was basically closed box equipped with various sensors and cameras, filled with remotely ignited cotton mixed with fiberglass. Experiment was designed to perform observation of flames in zero gravity conditions without risk of causing fire on International Space Station. Risk of fire is one of the most dangerous threats for astronauts in space and detailed observation, which was possible thanks to the cameras installed in Saffire container (with dimensions of 0.5 m x1 m x 1.5 m), will help in developing new technologies of fire extinguishing in space. Saffire was ignited remotely shortly after reaching by Cygnus safe distance from ISS, on June 14, 2016 at 20:55 GMT and was finished with full success. All necessary data were transmitted and device was turned off on June 19, 2016 at 13:41 GMT. Orbital ATK mission control center on Wallops, which was controlling Cygnus afar undocking, received 25 Gbits of data including over 20000 pictures taken by camera installed inside Saffire.
Reentry of Cygnus was planned for June 22, 2016 with impact zone over South Pacific. Cygnus fired its BT-4 engine to reduce speed and started lowering orbit to passed 80 km altitude at 13:29 GMT. REBR device was turned on and after reaching altitude of 40 km it was deployed from this what few minutes before was weighing 5000 kg Cygnus spacecraft. REBR capsule is equipped in GPS module, gyroscope, pressure, temperature and acceleration sensors, battery and Iridium data transmitting module-after deployment it started to transmit data via Iridium satellite mobile network. Device managed to send all data before it hit the waters of Pacific.
On picture above: Reentry of Cygnus in 2014.