As the Expedition 38 crew heads into its final weekend together aboard the International Space Station, the six astronauts and cosmonauts tackled a variety of science experiments Friday and prepared for the return home of three crewmates.
Commander Oleg Kotov and Flight Engineers Mike Hopkins and Sergey Ryazanskiy, who will be heading back to Earth Monday evening after 166 days in space, teamed up for a descent drill to train for their upcoming departure. The three crewmates climbed into their Soyuz TMA-10M spacecraft docked at the station’s Poisk module to review various scenarios for Monday’s undocking and landing to make sure they are prepared for any emergency situation that might arise.
On Monday, Kotov, Hopkins and Ryazanskiy will bid farewell to their fellow crewmates and board their Soyuz, closing the hatches at 4:45 p.m. EDT. The trio will undock from the station at 8:02 p.m. and land southeast of the town of Dzhezkazgan in Kazakhstan at 11:24 p.m. (9:24 a.m. Tuesday, Kazakhstan time). NASA TV will provide live coverage of all the departure and landing activities Monday.
Kotov and Ryazanskiy also tested the motion control and navigation system of their Soyuz and continued packing gear for the return home.
In addition to preparing for the journey home, Hopkins installed new filters in the glovebox for BioLab, a facility used to perform space biology experiments on microorganisms, cells, tissue cultures, plants and small invertebrates. Results from experiments performed inside BioLab could benefit biomedical research in such areas as immunology, pharmacology, bone demineralization and biotechnology.
Hopkins later checked in on the Binary Colloidal Alloy Test, or BCAT, which studies the kinetic behavior of solid materials suspended in a liquid. The NASA astronaut swapped out the batteries in a camera associated with the experiment and downloaded images. Results from this study will help material and industrial scientists develop product formulations to stabilize everyday commercial products.
Hopkins also weighed himself, which in a weightless environment requires a bit of physics and math instead of a traditional scale. The Space Linear Acceleration Mass Measurement Device, or SLAMMD, generates a known force against an astronaut attached to an extension arm and calculates the body mass within a half a pound using Newton’s Second Law.
Flight Engineer Rick Mastracchio meanwhile began his day the stowing tools and hardware he and Hopkins used on Thursday to perform maintenance on the Water Recovery System. Part of the station’s Environment Control and Life Support System, the Water Recovery System recycles condensation and urine into drinkable water, thereby reducing the amount of water that has to be sent up to the crew on resupply spacecraft. As NASA works toward sending humans deeper into space, beyond the reach of routine resupply cargo flights, the space station serves an important role as a testing ground for reliable regenerative life support hardware.
Later Mastracchio exchanged sample cartridges inside the Materials Science Laboratory’s Solidification and Quench Furnace. This metallurgical research furnace provides three heater zones to ensure accurate temperature profiles and maintain a sample's required temperature variations throughout the solidification process. This type of research in space allows scientists to isolate chemical and thermal properties of materials from the effects of gravity.
Working in the Kibo module, Flight Engineer Koichi Wakata set up the latest iteration of the Marangoni experiment inside the Fluid Physics Experiment Facility. Marangoni convection is the flow process that results from the difference in surface tensions where a liquid and a gas come together. By studying this process in microgravity, researchers hope to uncover fundamental properties that could improve the production of semiconductors and optical crystals and contribute to various micro-fluid handling techniques, such as those used in DNA examination and clinical diagnostics.
Wakata also set up a microscope to give researchers a close-up look at the Aniso Tubule experiment, which is studying the mechanisms that plants use in growing stems of the right thickness to support themselves against gravity. The Japanese astronaut also refilled the water supply for the thale cress seedlings within the experiment’s sample chamber.
On the Russian side of the complex, Flight Engineer Mikhail Tyurin collected surface samples to check for signs of biodegradation and performed routine maintenance on the life-support system in the Zvezda service module.
Tyurin later joined up with Wakata and Mastracchio for a review of emergency roles and responsibilities aboard the station following Monday’s departure of Kotov, Ryazanskiy and Hopkins.
Over the weekend, the crew will continue preparations for undocking, with Kotov and Ryazanskiy using the Lower Body Negative Pressure device to condition their bodies for the return to the full-force of Earth’s gravity. This device simulates the effects of gravity by drawing fluids to the lower half of the body.
Hopkins, Mastracchio and Wakata took part in the South by Southwest Technology Conference on Saturday as they answered questions from audience members gathered in Austin, Texas. The 20-minute in-flight event was carried live on NASA TV beginning at 12:40 p.m.
On Sunday, Kotov passed the helm of the station to Wakata during a Change of Command ceremony. Monday’s departure of Kotov, Hopkins and Ryazanskiy will signal the end of Expedition 38 and the beginning of Expedition 39 under the leadership of Wakata, the first Japan Aerospace Exploration Agency astronaut to command the station. Wakata, Mastracchio and Tyurin, who arrived at the orbiting complex Nov. 7, will remain aboard the station until mid-May.
Meanwhile the three flight engineers who will return the station’s crew to its full six-person complement are in the homestretch of preparations for launch. NASA astronaut Steve Swanson and Russian cosmonauts Alexander Skvortsov and Oleg Artemyev completed their qualification exams this week at the Gagarin Cosmonaut Training Center in Star City, Russia. On March 13, they will fly to the launch site at the Baikonur Cosmodrome in Kazakhstan to begin the final phase of training for their launch on March 25 aboard the Soyuz TMA-12M spacecraft.