SpaceX is readying a Falcon 9 rocket and a Dragon cargo ship for launch Sunday to deliver more than 4, 000 pounds of equipment, supplies and science gear to the International Space Station, including the first of two new docking adapters needed to capture American crew capsules being built by Boeing and SpaceX.
The science instruments and supplies cover a wide range of disciplines, including work to help figure out what is causing vision problems in three quarters of the astronauts who make long-duration space flights. A customized camera will photograph shooting stars from above to determine their chemical composition and the station crew will attempt to grow cabbage that can be added to the lab's menu.
Other experiments include studying how genes are turned on and off in weightlessness, how microorganisms grow and move through the station and tests to better understand how implantable drug delivery systems work at the molecular level to improve performance on Earth. Also on board: more than two dozen student experiments.
"There are about 35 different experiments that are going up or down on SpaceX 7, and those support the over 250 active investigations we have going on on ISS right now, " said Julie Robinson, space station program scientist.
The Canadarm 2 reaches out to capture the SpaceX Dragon cargo spacecraft and prepare it to be pulled into its port on the International Space Station Friday April 17, 2015.
While getting the Dragon to the space station is the primary objective of the mission, SpaceX plans to make a third attempt to land the rocket's first stage on off-shore remotely-operated barge, or drone ship. Recovering booster stages and flying them again is a key element in founder Elon Musk's drive to lower launch costs.
During the first attempt in January, the descending rocket stage ran out of hydraulic fluid and crashed into the "Just Read the Instructions" drone ship. A second try in April almost worked, but a valve problem caused a loss of control seconds before touchdown and the booster tipped over and exploded.
This time around, Hans Koenigsmann, SpaceX vice president of mission assurance, said he was hopeful, but cautioned that success was far from certain.
"It's hard to say what the odds are, if it's better than the last one or not, " he told reporters Friday. "There is always uncertainty until we basically solve this problem end to end. But I feel a little bit better (about the outcome)."
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