Spacewalk Preps and Communications Upgrade on Station
On the eve of a scheduled six-hour spacewalk, the Expedition 35 crew completed a wide-range of science experiments and wrapped up the installation of a new communication system that will enhance the research capabilities of the International Space Station.
Commander Chris Hadfield of the Canadian Space Agency and Flight Engineer Tom Marshburn of NASA began their workday by participating in several ongoing human research studies. Both astronauts tested their urine for the Pro K experiment as nutritionists monitor how dietary changes affect the bone loss that occurs during spaceflight. Afterward, Hadfield drew a blood sample from Marshburn who then processed and stored the sample in the Minus Eighty-Degree Laboratory Freezer for ISS, or MELFI, to preserve it until it can be returned to Earth for study.
Marshburn’s fellow NASA astronaut aboard the station, Flight Engineer Chris Cassidy, began his day downloading sound environment data from acoustic dosimeters worn by crew members earlier this week. Cassidy then deployed the dosimeters at various locations throughout the complex to continue tracking the noise levels that crew members are exposed to.
After the crew’s daily planning conference with flight control teams around the world, Cassidy spent much of his day setting up and operating the Capillary Flow Experiment. Results from this experiment, which takes a close look at how fluids flow across surfaces with complex geometries in a weightless environment, will improve computer models used to design fluid transfer systems and fuel tanks on future spacecraft.
› Read more about the Capillary Flow Experiment
Hadfield and Marshburn meanwhile wrapped up the upgrades to the new High Rate Communications System today by connecting coaxial cables to bus-tie the new Ku Communications Unit 1 to its redundant Ku Communications 2. Ku band communications were down for several hours during the mating of these cables and the ensuing checkout. The upgrades, which add two additional video downlink channels from the station and doubles the number of space-to-ground channels, has greatly enhanced the ability of researchers on Earth to get data to and from their experiments aboard the station.
Commander Hadfield also completed his final day with the Energy experiment. During the 10 days he participated in the study, Hadfield followed a prescribed diet and participated in data-collecting exercise sessions aimed at precisely measuring the dietary requirements for astronauts during long-duration space missions.
› Read more about the Energy experiment
Marshburn rounded out his day reviewing procedures for his first onboard session with the BP Reg experiment slated for Friday. BP Reg is a Canadian medical experiment that seeks to understand the causes of fainting and dizziness seen in some astronauts when they return to Earth following a long-duration mission. BP Reg collects data before, during and after the mission using inflatable cuffs attached to the legs. The experiment will not only help understand dizziness in astronauts, but also have direct benefits for people on Earth – particularly those predisposed to falls and resulting injuries, as seen in the elderly.
› More on BP Reg from the Canadian Space Agency
On the Russian side of the station, Flight Engineers Pavel Vinogradov and Roman Romanenko completed final preparations for a six-hour spacewalk they will conduct Friday. The two cosmonauts, along with Commander Hadfield, participated in a procedure review with Russian spacewalk specialists to discuss the timeline for Friday’s excursion. Vinogradov and Romanenko later refilled and installed drink bags into their Orlan spacesuits.
During the spacewalk slated to begin at 10:06 a.m. EDT, Vinogradov and Romanenko will deploy and retrieve several experiment packages on exterior of the Russian segment of the complex. The two spacewalkers also will replace a faulty retro-reflector device, one of a suite of navigational aids that will provide assistance to the European Space Agency's Albert Einstein Automated Transfer Vehicle 4 cargo ship during its final approach for an automated docking to the space station in June.
NASA Television will broadcast the spacewalk live beginning at 9:30 a.m.
› Watch NASA TV
› Read more about Friday's spacewalk
The third Russian cosmonaut, Flight Engineer Alexander Misurkin, worked with the Constant experiment, which studies the effect of microgravity on a model enzyme. Misurkin rounded out his day with the Vzaimodeystviye (Interactions) experiment, which monitors the crew’s adaptation to long-duration spaceflight.
On Wednesday, the first launch attempt to send Orbital Sciences Corp.'s Antares rocket on a test flight was scrubbed at the T-12 minute mark due to a premature separation of the launch pad umbilical that mates to Antares.
Orbital has confirmed the next opportunity to test launch its Antares rocket from NASA's Wallops Flight Facility in Virginia will be no earlier than 5 p.m. on Saturday, April 20. NASA TV coverage of the launch will begin at 4:30 p.m. By the time coverage starts, the launch window will likely have been reduced to 10-15 minutes.
An attempt Friday was called off after review of the weather forecast. Saturday’s forecast indicates an 85 percent chance of favorable conditions. If needed, a back-up launch opportunity is available on Sunday.
› Latest Antares launch information
Antares is undergoing testing that will enable the rocket to eventually carry experiments and supplies to the International Space Station aboard a Cygnus cargo spacecraft. This test flight will not launch a Cygnus spacecraft or rendezvous with the space station.
Orbital is testing the Antares rocket under NASA's Commercial Orbital Transportation Services (COTS) program. NASA initiatives like COTS are helping develop a robust U.S. commercial space transportation industry with the goal of achieving safe, reliable and cost-effective transportation to and from the space station and low-Earth orbit.
› Read more about Expedition 35