( CNN ) -- SpaceX 's Dragon spaceship splashed down Saturday in the Pacific Ocean , returning from a four-week resupply mission to the International Space Station and bringing back a valuable payload of potentially groundbreaking experiments . Dragon , an unmanned spacecraft , successfully came down about 300 miles west of Baja California just after 3:30 p.m. EST , carrying a return load weighing 3,276 pounds , NASA said in a press release . Dragon was expected to be hauled to a port near Los Angeles where some of the cargo would be removed almost immediately , the space agency said , while the rest of the research aboard the rocket will return to SpaceX 's facility at McGregor , Texas , for further processing . SpaceX is a private company that has contracted with NASA to fly missions to the ISS since NASA retired its shuttle fleet in 2011 . `` 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 . One of the experiments scientists are hoping yields information to help further deep space exploration involves mice . It 's called the Rodent Research-1 . Part of that experiment has returned aboard the Dragon . The study focuses on `` ongoing research on how microgravity affects animals , providing information relevant to human spaceflight , discoveries in basic biology and knowledge that may directly affect human health on Earth , NASA said . The Dragon also delivered a 3-D printer to the ISS during its mission , to test the ability to produce parts cheaply and on demand , and a device called the ISS-RapidScat that will measure the winds on the Earth 's oceans for climate and weather research . `` The delivery of the ISS RapidScatterometer advances our understanding of Earth science , and the 3-D printer will enable a critical technology demonstration , '' Scimemi said . Also critical to extended space travel is a dependable food supply . A study on arugula plant growth returned aboard the Dragon . The research hopes to determine the impact of various nutrients and microgravity on seedlings from the leafy vegetable that are grown in space . Scientists hope the experiment will help them learn the best ways to grow plants in space with the highest nutritional content . The Dragon delivered a total of 255 science experiments to the ISS during its fourth of 12 planned SpaceX resupply missions to the space station through 2016 . The next SpaceX flight is set to lift off sometime after December 1 . It will also deliver crew supplies and cargo to the International Space Station , including CATS , the Cloud-Aerosol Transport System . CATS is a laser instrument that will measure clouds and particles in the atmosphere , including pollution , dust and smoke . NASA recently announced it was awarding $ 6.8 billion contracts to SpaceX and Boeing to shuttle cargo and astronauts to and from the ISS . Since NASA 's space shuttle program was retired in 2011 , astronauts have been hitching rides on the Soyuz spacecraft , at a cost of $ 70 million per seat . Both Boeing and SpaceX 's crafts will go through a certification process first . The target date to begin manned missions is 2017 . CNN 's Natalie Snedden contributed to this report .
Rodent 's Dragon successfully returns from One NASA resupply mission . ISS : Mission carried critical research for human space exploration . NASA delivered 3-D printer and device to measure Earth 's ocean winds . Next mission could come before year 's end .