Hatches sealed on ISS pump-up space podule
Inflatable habitat in good shape
The hatches have been closed on the International Space Station's (ISS) Bigelow Expandable Activity Module, following three days' work by astronaut Jeff Williams installing sensors and other hardware inside the pump-up space podule.
BEAM will spend two years attached to the orbiting outpost's Tranquility module, as NASA and Bigelow Aerospace gauge how it performs in the rigours of space. The habitat arrived at the ISS in a compressed state aboard a SpaceX Dragon resupply capsule back in April, and was finally inflated to its full 16m3 at the second attempt a couple of weeks ago.
The engorgement of BEAM. Pic: NASA TV
BEAM isn't intended for general use, and astronauts will only enter "between 12 and 14 times during its stay" to assess its condition. At the end of the tests, BEAM will be jettisoned ahead of a fiery death in Earth's atmosphere.
The reason for this apparent waste of a perfectly good podule is that parking is commonly tight at the ISS.
The current parking situation at the ISS. Pic: NASA
On 14 June, the Orbital ATK Cygnus-6 space delivery truck which docked on 26 March will be cut loose from the station. It'll be packed with ISS waste and the the Spacecraft Fire Experiment-I (Saffire-I)* payload, which will deliberately start a "large-scale fire" inside the vehicle. Sensors will transmit data on "flame growth, oxygen use and more" before the Cygnus re-enters the atmosphere and is entirely consumed by fire over the Pacific.
Another parking spot will be freed up with the departure on 18 June of the Soyuz TMA-19M, carrying Expedition 47 crew members Tim Kopra, Yuri Malenchenko and Tim Peake homewards at the end of 186 days in space.
Tim Peake, Yuri Malenchenko and Tim Kopra pose with Soyuz lifter before heading to the ISS
The trio of returning 'nauts will be replaced by Expedition 48 team Anatoly Ivanishin, Takuya Onishi and Kate Rubins, who are due to depart Baikonur cosmodrome on 7 July aboard a new Soyuz MS capsule.
Takuya Onishi, Anatoly Ivanishin and Kate Rubins. Pic: NASA
The Soyuz MS is an improved version of the venerable TMA, featuring "improved position control engine and a GLONASS/GPS system", plus a "new approach and docking system, a new computer, and more power efficient solar panels".
This first mission for the MS, designated Soyuz MS-01, was slated for blast-off on 24 June, but was rescheduled for July to carry out further software testing due to "the risk of a glitch in the control system". ®
Here's NASA's background blurb on Saffire:
Despite decades of research into combustion and fire processes in reduced gravity, there have been very few experiments directly studying spacecraft fire safety under low-gravity conditions. Furthermore, none of these experiments have studied sample and environment sizes typical of those expected in a spacecraft fire. Prior experiments have been limited to samples no larger than 10 cm in length and width. This stands in stark contrast to the full-scale fire safety testing that has been conducted in habitable structures on earth including mines, buildings, airplanes, ships, etc.
The large differences between fire behavior in normal and reduced gravity results in a lack of experimental data that forces spacecraft designers to base their designs on terrestrial fires and fire standards. While this approach has been successful thus far, there is inherent risk due to the level of uncertainty. Despite their obvious importance, full scale spacecraft fire experiments have not been possible because of the inherent hazards involved in conducting a large fire test in a manned spacecraft. To address this knowledge gap, experiments in an expendable spacecraft are proposed and conducted without risk to crew or crewed spacecraft.