[image-78]Having said farewell to their Expedition 39 crewmates just three days ago, the three-person Expedition 40 crew spent Friday getting ready for the next vehicle departure from the International Space Station – the SpaceX Dragon cargo craft carrying more than 3,500 pounds of NASA science samples and cargo back to Earth.
On Sunday, Dragon will be detached from the Earth-facing side of the station's Harmony module and unberthed through commands sent by robotic ground controllers at mission control in Houston operating the Canadarm2 robotic arm. Once the vehicle is maneuvered remotely to the release point, Commander Steve Swanson, with assistance from Flight Engineer Alexander Skvortsov, will release Dragon at 9:26 a.m. EDT and monitor its departure. The commercial cargo craft will execute three thruster firings to move a safe distance away from the station for its deorbit burn at 2:08 p.m. Dragon, which delivered about 2.5 tons of science and supplies to the station for the SpaceX-3 commercial resupply services mission when it arrived at the complex April 20, will splash down for recovery off the coast of California at 3:02 p.m. (12:02 p.m. PDT).
Live NASA Television coverage of the departure begins at 9 a.m. Sunday. Neither the deorbit burn nor the splashdown will be broadcast on NASA TV.
Swanson focused much of his efforts Friday on loading Dragon with the results of recent station experiments. One of those experiments, the National Lab Pathfinder Vaccine-21, also known as the Antibiotic Effectiveness in Space investigation, is taking a look at the gene expression patterns and changes of E. coli to learn more about drug-resistant bacteria.
[image-94]The commander later transferred a Commercial Generic Bioprocessing Apparatus containing the Micro-7 experiment into Dragon. Micro-7 takes a look at how microgravity affects the genetic expression and physical shape of non-dividing cells, which are the majority of cells that make up the human body.
Skvortsov teamed up with Swanson to swap out a GLACIER freezer aboard Dragon with one from the station filled with completed science samples. Swanson also moved another science-packed GLACIER freezer into Dragon. Short for General Laboratory Active Cryogenic ISS Experiment Refrigerator, GLACIER refrigerators are ultra-cold freezers that will store samples at temperatures as low as -301 degrees F. Flight Engineer Oleg Artemyev later joined his crewmates to video the installation of the second GLACIER into Dragon.
Swanson also checked in on the Space Pup experiment, which is the first step towards studying the effects of space radiation on mammalian reproduction.
The station commander rounded out his day with a little gardening as he tended to the red romaine lettuce seedlings growing in the Veggie plant facility. For the Veg-01 experiment, researchers are testing and validating the Veggie hardware, and the plants will be harvested and returned to Earth to determine food safety.
Before Swanson closes up the hatch to Dragon on Saturday, he and Skvortsov will spend the day loading up the remaining cargo into the visiting vehicle and reviewing the procedures for its robotic release.
[image-51]Swanson, Skvortsov and Artemyev have been operating the station as a three-person crew since the departure of their Expedition 39 crewmates – Commander Koichi Wakata and Flight Engineers Rick Mastracchio and Mikhail Tyurin – on Tuesday.
Meanwhile at the Baikonur Cosmodrome in Kazakhstan, the three flight engineers who will return the station to its full six-person crew complement are now in the homestretch of preparations for launch. Reid Wiseman of NASA, Max Suraev of Roscosmos and Alexander Gerst of the European Space Agency will launch aboard their Soyuz TMA-13M spacecraft at 3:57 p.m. on May 28 (1:57 a.m. May 29, Kazakh time) to begin a six-hour trek to the orbiting complex.