Dragon is loaded with about 1,268 pounds (575 kilograms) of supplies to support continuing space station research experiments and will return with about 2,668 pounds (1,210 kilograms) of science samples from human research, biology and biotechnology studies, physical science investigations, and education activities.Newly delivered investigations include studies of how molecular biology, cells and plants grow in microgravity. One experiment, titled Coarsening in Solid Liquid Mixtures-3, will examine solid and liquid mixtures made of lead and tin that contain a small amount of tin branch-like structures called dendrites. By understanding how temperature and time control the growth of such dendrites, researchers hope to develop more efficient and economical means of producing higher-quality products derived from the casting of molten metals. New student experiments include observing how gravity changes the growth of E. coli bacteria, studying the long-term impact of space travel on small coin-cell-sized batteries, and producing ammonium aluminum sulfate crystals of higher purity than is possible on Earth. Experiment samples coming back to Earth will help researchers continue to assess the impact of long-duration spaceflight on the human body. Returning plant samples will aid in food production during future long-duration space missions and enhance crop production on Earth. Crystals grown aboard and returning from the station could help in the development of more efficient solar cells and semiconductor-based electronics. The Dragon capsule is scheduled to spend 22 days attached to the station before returning for a splashdown in the Pacific Ocean off the coast of Baja California March 25. This flight is the second of at least 12 SpaceX cargo resupply missions to the space station through 2016. The resupply contract with NASA is worth $1.6 billion. NASA's Space Network, which includes the Tracking and Data Relay Satellite System, provided space communications for SpaceX from launch through berthing with the space station.