The International Space Station (ISS) is a collaborative project involving NASA, Roscosmos, JAXA, ESA, and CSA, serving as a microgravity and space environment research laboratory. On January 15, 2015, the ISS was in the midst of Expedition 42, a mission that began in November 2014 and concluded in March 2015. This period was marked by significant scientific activities, technical challenges, and international cooperation.

Ammonia Leak False Alarm

On January 14, 2015, at 3:58 AM CST, the ISS telemetry system indicated a potential ammonia leak within Node 2 of the U.S. Segment. In response, the crew initiated emergency procedures, evacuating the U.S. Segment and isolating themselves in the Russian Segment. This precautionary measure led to the shutdown of the External Thermal Control System (ETCS) Loop B, the Node 2 Low Temperature Loop (LTL), and various equipment in the Node 2, Node 3, Japanese Experiment Module (JEM), and Columbus modules. Ground teams analyzed the telemetry data and determined that the alarm was triggered by an erroneous signal from the Node 2-2 Multiplexer/Demultiplexer (MDM). After power cycling the MDM, the telemetry readings returned to normal, and the crew re-entered the U.S. Segment, confirming the absence of ammonia. Recovery efforts for Loop B and the affected systems were underway. ([nasa.gov](

External Thermal Control System (ETCS) Loop B Recovery

Following the false alarm, ground teams focused on methodically repressurizing and recovering ETCS Loop B and the systems that were deactivated as a result. The Loop B Interface Heat Exchangers (IFHX) remained bypassed and isolated, preventing internal heat rejection on Loop B. Consequently, half of the power loads in the Node 2, JEM, and Columbus modules remained powered down. ETCS Loop A continued to operate nominally. ([](

Conjunction with Object #27317

On January 15, 2015, ground teams evaluated tracking data for a possible conjunction with Object #27317. The debris was small, experienced about seven times as much drag as the ISS, and was reasonably well-tracked. The closest approach was projected for January 16, 2015, at 9:03 AM CST. If necessary, a Pre-Determined Debris Avoidance Maneuver (PDAM) was planned for 6:43 AM CST. ([](

General Laboratory Active Cryogenic ISS Experiment Refrigerator (GLACIER) 4 Issues

GLACIER 4, a refrigerator designed to store biological samples, exhibited issues controlling internal temperatures. While ground teams worked on troubleshooting the problem, astronaut Terry Virts moved science samples from GLACIER 4 to the MERLIN 3 freezer to ensure the preservation of the samples. ([](

Scientific Activities and Experiments

During this period, the ISS crew engaged in various scientific experiments and maintenance tasks. Notably, the Cloud-Aerosol Transport System (CATS) was launched in January 2015. CATS is a lidar remote sensing instrument designed to provide range-resolved profile measurements of atmospheric aerosols and clouds from the ISS. The mission aimed to operate for at least six months, with the potential to extend up to three years, contributing valuable data to atmospheric science. ([cats.gsfc.nasa.gov](

Additionally, the crew conducted operations related to the NanoRack Cubesat Deployer (NRCSD), deploying multiple CubeSats into orbit. These deployments supported various research initiatives, including Earth observation and technology demonstrations. ([nasa.gov](

Conclusion

On January 15, 2015, the ISS was actively engaged in scientific research, technical maintenance, and operational procedures. The crew's prompt response to the ammonia leak false alarm, ongoing recovery efforts for ETCS Loop B, and participation in various scientific experiments underscore the ISS's role as a hub for international collaboration and space exploration. The events of this day highlight the dynamic nature of life aboard the ISS and the continuous efforts to ensure its operational success and scientific productivity.

Sources

  • NASA — ISS Daily Summary Report – 01/14/15 —
  • NASA — ISS On-Orbit Status Report – NASA —
  • NASA — ISS On-Orbit Status Report – NASA —
  • NASA — ISS On-Orbit Status Report – NASA —
  • NASA — ISS On-Orbit Status Report – NASA —