SpaceX officially closed out their fourth dedicated Dragon resupply mission for NASA today with a successful splashdown landing of the unmanned orbital cargo ship in the Pacific Ocean 300 miles west of Baja California, Mexico, closing out a five-week mission to restock the International Space Station (ISS) with over 2.5 tons of cargo and science experiments for the Expedition 41 crew currently stationed at the orbiting outpost. Splashdown was confirmed at 3:38 p.m. EDT, with Dragon returning 3,276 pounds of various NASA cargo and science experiments from the ISS.
Once Dragon is secured the spacecraft will be towed to a port near Los Angeles, where some cargo will be removed and returned to NASA within 48 hours. Afterwards, the spacecraft will be prepared for a return journey to SpaceX’s test facility in McGregor, Texas, for processing.
“This mission enabled research critical to achieving NASA’s goal of long-duration human spaceflight in deep space,” said Sam Scimemi, director of the International Space Station division at NASA Headquarters. “The delivery of the ISS RapidScatterometer advances our understanding of Earth science, and the 3-D printer will enable a critical technology demonstration. Investigations in the returned cargo could aid in the development of more efficient solar cells and semiconductor-based electronics, the development of plants better suited for space, and improvements in sustainable agriculture.”
Among the investigations that returned home aboard Dragon was part of the Rodent Research-1 experiment, a study that supports ongoing research into how microgravity affects animals, providing information relevant to human spaceflight, discoveries in basic biology, and knowledge that may directly impact the health of people around the world.
NanoRacks-Girl Scouts of Hawai’i-Arugula Plant Growth study also returned to Earth aboard Dragon this weekend. The study seeks to determine the impact that various nutrients and microgravity have on the growth and nutritious value of arugula seedlings grown in space, with the goal to develop better ways to grow plants with a high nutritional content in the space environment. If the study samples have a high nutritional value, this may enable NASA and astronauts to grow and consume fresh, healthy food during future space travel, which is critical for any deep space human exploration plans that NASA takes on, such as those the agency is looking to begin flying starting early in the 2020s with their SLS/Orion vehicles.
Among the 5,000 pounds of supplies Dragon delivered to the ISS was 1,644 pounds of scientific experiments and materials to support 255 research investigations which will take place during the current Expedition 41 and forthcoming Expedition 42 missions. Those science experiments will enable model organism research, using rodents, fruit flies, and plants, whilst several new technology demonstrations will permit studies of astronauts’ bone densities, the movement and positioning of small satellites with state-of-the-art thrusters, and the first 3-D printer in space for additive manufacturing. Dragon also delivered two new Long Life Batteries (LLBs) for the U.S. Extravehicular Mobility Unit (EMU) space suits; an issue with the LLBs currently aboard the ISS caused a pair of U.S. EVAs in August to be deferred, and they are now expected to take place on Oct. 6, 8 and 15, involving U.S. Orbital Segment (USOS) crewmen Reid Wiseman, Alexander Gerst, and Barry “Butch” Wilmore.
Dragon also delivered NASA’s $26 million Rapid Scatterometer (RapidScat) to the ISS on CRS-4, a 1,300-pound experiment that will monitor the velocity and direction of oceanic winds, which is expected to yield valuable data to complement three other operational satellite scatterometers (the European MetOp-A and MetOp-B missions and India’s OceanSat-2). RapidScat’s position aboard the ISS, which operates in a high-inclination orbit of 51.6 degrees to the equator, will allow it to cross the orbital tracks of its three sister satellites, thus providing a valuable calibration source. Since oceanic winds are greatly affected by solar radiation—which also varies with the time of day—trends which currently escape the notice of the European and Indian scatterometers should be detectable by RapidScat.
“We’ll be able to see how wind speed changes with the time of day,” said Project Scientist Ernesto Rodríguez. “RapidScat will link together all previous and current scatterometer missions, providing us with a more complete picture of how ocean winds change. Combined with data from the European ASCAT scatterometer mission, we’ll be able to observe 90 percent of Earth’s surface at least once a day, and in many places, several times a day.”
The mission marked the sixth Falcon 9 v1.1 launch of 2014 and the company’s second Dragon mission of the year to the ISS, following the launch of the AsiaSat-6 geostationary communications satellite less than two weeks prior. With Dragon now back on Earth, SpaceX is turning their focus toward launching the fifth of 12 dedicated Dragon missions (CRS-5) under SpaceX’s $1.6 billion Commercial Resupply Services contract with NASA as early as Dec. 9, 2014.
The mission will see the unmanned Dragon capsule return to the ISS, bringing with it (among other things) NASA’s Cloud-Aerosol Transport System (CATS), which is a laser instrument to measure clouds and the location and distribution of pollution, dust, smoke, and other particulates in Earth’s atmosphere.
The mission will also give SpaceX another opportunity to test the vertical landing ability of their Falcon-9 v1.1 booster, something the company has been focusing on throughout the year on low-Earth orbit (LEO) launches as they continue developing the technology needed to “change the game” and provide customers with a truly reusable rocket, which would drive down costs substantially, according to the company’s CEO Elon Musk. But previous landing attempts have taken place in the ocean, not on a solid surface; however, Florida Today has confirmed that the 14-story-tall CRS-5 F9 booster will be guided to a controlled vertical landing on a football field-sized barge positioned in the Atlantic off the coast of Florida, which measures 300 feet by 170 feet and is currently being prepared at a shipyard in Louisiana. Eventually SpaceX hopes to return their boosters back to the launch site itself, but first they must prove to the world they can do so safely, and repeatedly, offshore.
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