55 Soyuz (55S) Undock and Landing: The 55S crew, Sergey Prokopev, Alexander Gerst, and Serena Auñón -Chancellor, are scheduled to return to Earth tonight. Undock is scheduled for 7:40 PM CT with landing at 11:03 PM CT. The crew is scheduled to arrive at Ellington on Friday, December 21.

Bone Densitometer Calibration: The crew performed the calibration for the Bone Densitometer using a phantom (calibration) mouse. Approximately the size of a consumer microwave oven, the Bone Densitometer (BD) uses X-rays to measure the bone mineral density (and the lean and fat tissue) of mice living aboard the ISS. As a result, researchers hope to develop medical technology that will combat bone density loss in space and on Earth, helping millions of senior citizens who suffer from osteoporosis. Bone Densitometer will be used to support the ongoing Rodent Research-8 investigation.

Functional Immune and Standard Measures (separate investigations): Blood and Saliva samples were collected in support of the Functional Immune and Standard Measures investigations. The Functional Immune Alterations, Latent Herpesvirus Reactivation, Physiological Stress and Clinical Incidence Onboard the International Space Station (Functional Immune) investigation analyzes blood and saliva samples to determine the changes taking place in crew members’ immune systems during flight. The aim of the Standard Measures investigation is to ensure consistent capture of an optimized, minimal set of measures from crewmembers until the end of the ISS Program in order to characterize the adaptive responses to and risks of living in space.

Time Perception: The crew performed the Time Perception experiment using a virtual reality headset and headphones. A laptop program induces visual and audio stimuli to measure a subject’s response to spatial and time perception in a microgravity environment. The accurate perception of objects in the environment is a prerequisite for spatial orientation and reliable performance of motor tasks. Time is fundamental to motion perception, sound localization, speech, and fine motor coordination.

Completed Task List Activities:

None

Ground Activities:

All activities are complete unless otherwise noted.



55S undock activities

Two-Day Look Ahead:

Thursday, 12/20: – Crew Off Duty

Friday, 12/21:

Payloads

Actiwatch plus check

Lighting Effects

Nanoracks mod 74

Systems

OBT ISS emergency hardware familiarization

WPA MF bed sample collect

Ice brick/double cold bag stow

Today’s Planned Activities:

All activities are complete with the exception of Soyuz undocking events unless otherwise noted.

