NASA Space Station On-Orbit Status 29 September 2020 – Leak Continues to Mystify
Late Monday night, the Expedition 63 crew was awakened by flight controllers to continue troubleshooting a small leak on the International Space Station that appeared to grow in size.
Ground analysis of the modules tested overnight have isolated the leak location to the main work area of the Zvezda Service Module. Additional work is underway to precisely locate the source of the leak.
The leak, which has been investigated for several weeks, poses no immediate danger to the crew at the current leak rate and only a slight deviation to the crew’s schedule.
NASA astronaut and station commander Chris Cassidy and Roscosmos cosmonauts Anatoly Ivanishin and Ivan Vagner were instructed to move into the Russian segment to collect data at various locations in the Russian modules. The size of the leak identified overnight has since been attributed to a temporary temperature change aboard the station with the overall rate of leak remaining unchanged.
Previous leak checks were conducted in the U.S., European and Japanese modules in the U.S. segment of the station.
One by one, the crew closed hatches between Zvezda’s aft and forward sections and Zvezda’s passageways to the Pirs Docking Compartment and the Poisk module while using an ultrasonic leak detector to collect data. Throughout the night, pressure measurements were taken by U.S. and Russian specialists to try to isolate the source of the leak. At the completion of the overnight checks, the crew opened hatches once again between the U.S. and Russian segments and resumed regular activities.
The crew is preparing for this weekend’s arrival of the uncrewed Northrop Grumman Cygnus cargo craft which is scheduled for launch Thursday night from the agency’s Wallops Flight Facility, Virginia, as well as the upcoming launch of the next trio of residents for the station. NASA astronaut Kate Rubins and cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov are at the Baikonur Cosmodrome in Kazakhstan, preparing for launch to the complex on Oct. 14.
On-Orbit Status Report
Payloads
Radi-N2 Retrieve: The crew retrieved the eight Radi-N2 bubble detectors from their deployed location near windows 3 and 4 in the Cupola, and handed over the Russian crew for processing. The detectors had been deployed in this location for one week. The objective of this Canadian Space Agency investigation is to better characterize the ISS neutron environment, define the risk posed to the crew members’ health, and provide the data necessary to develop advanced protective measures for future spaceflight. It’s been recognized that neutrons make up a significant fraction (10-30%) of the biologically effective radiation exposure in low-Earth orbit. The bubble detectors used in the investigation are designed to detect neutrons and ignore all other radiation.
Systems
ISS Leak Detection Operations: Yesterday, following the conclusion of the weekend leak isolation test, ground teams began to observe an increase of the ISS leak rate. The unexpected increase in the leak rate led the on-console team to wake the crew to take action. The crew ran a modified emergency response procedure which highly suggested the leak location was in the vicinity of the Service Module. Once the suspected volumes were identified, the crew stepped into some initial actions to try and locate the leak. While the leak rate was initially observed to increase over about a 13 hour period, the rate leveled out to previous values early this morning. The teams continue to work a forward plan and all the data collected overnight is being reviewed.
Completed Task List Activities:
None
Today’s Ground Activities:
All activities are complete unless otherwise noted.
Nitrogen Repress (6.5mmHg)
Electrical Power System (EPS) Solar Array Voltage Maximum Power
Look Ahead Plan
Wednesday, 9/30 (GMT 274)
Payloads:
EarthKAM Lens Change
HXP2 Safing Ops
Robo-Pro Rehearsal 2
Systems:
OBT Cygnus Offset Grapple
Thursday, 10/1 (GMT 275)
Payloads:
Avatar-X Setup
GLACIER2 Desiccant Swap
Systems:
EMU Loop Scrub
HMS PHS Exam
EMU Swap
Friday, 10/2 (GMT 276)
Payloads:
Echo Hard Drive Install
Payload NAS Vent Clean
Systems:
ARED Qtrly Inspection
Cygnus Capture Rvw
Cygnus Cargo Rvw/Conf
PCS Relocates
Cygnus ROBoT OBT – Session 2
Today’s Planned Activities:
All activities are complete unless otherwise noted.
ISS Leak Detection using Ultrasonic Leak Detector (ULD)
