The fourth SpaceX cargo mission to the International Space Station (ISS) under NASA's Commercial Resupply Services contract, carrying the ISS-RapidScat scatterometer instrument designed and built by NASA's Jet Propulsion Laboratory, Pasadena, California, is scheduled to launch Saturday, Sept. 20, from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

The one-day adjustment in the launch date was made to accommodate preparations of the SpaceX Falcon 9 rocket and was coordinated with the station's partners and managers.

The company's Falcon 9 rocket, carrying its Dragon cargo spacecraft loaded with more than 5,000 pounds (2, 270 kilograms) of scientific experiments and supplies, will lift off at 11:16 p.m. PDT Sept. 19 (2:16 a.m. EDT Sept. 20). NASA Television coverage of the launch begins at 10:15 p.m. PDT (1:15 a.m. EDT). If for any reason the launch is postponed, the next launch opportunity is Saturday, Sept. 20, at approximately 10:53 p.m. PDT (Sunday, Sept. 21, at approximately 1:53 a.m. EDT).

The mission, designated SpaceX CRS-4, is the fourth of 12 SpaceX flights NASA contracted with the company to resupply the space station. It will be the fifth trip by a Dragon spacecraft to the orbiting laboratory.

The spacecraft's 2.5 tons of supplies, science experiments, and technology demonstrations include critical materials to support 255 science and research investigations that will occur during the station's Expeditions 40 and 41.

Science payloads include the ISS-Rapid Scatterometer to monitor ocean surface wind speed and direction; new biomedical hardware that will help facilitate prolonged biological studies of rodents in microgravity; and a study of a small flowering plant related to cabbage that allows scientists to study plant growth and adaptations in space.

New technology demonstrations aboard the Dragon spacecraft include the Special Purpose Inexpensive Satellite, or SpinSat, to test how a small satellite moves and positions itself in space using new thruster technology and the 3-D Printing In Zero-G Technology Demonstration, the first 3-D printer in space.

NASA will host a series of prelaunch news conferences Thursday, Sept. 18, and Friday, Sept. 19, at the agency's Kennedy Space Center in Florida, which will be carried live on NASA TV and the agency's website.

During panel discussions Sept. 18 at 6, 7 and 8 a.m. PDT (9, 10 and 11 a.m. EDT), scientists and researchers will discuss the various science and research studies, including RapidScat, 3-D printing in Zero-G, technology to measure bone density, and model organism research using rodents, fruit flies and plants.

NASA senior leaders will host a briefing Sept. 19 at 6 a.m. PDT (9 a.m. EDT), followed by a prelaunch news conference at 7 a.m. PDT (10 a.m. EDT), at the agency's Kennedy Space Center in Florida. All these briefings, which are subject to a change in time, will be carried live on NASA TV and the agency's website. A post-launch briefing will be held approximately 90 minutes after launch.

If launch occurs Sept. 20, NASA TV will provide live coverage Monday, Sept. 22, of the arrival of the Dragon cargo ship to the International Space Station. Grapple and berthing coverage will begin at 2:30 a.m. PDT (5:30 a.m. EDT) with grapple at approximately 4:30 a.m. PDT (7:30 a.m. EDT). Berthing coverage begins at 6:30 a.m. PDT (9:30 a.m. EDT).

The Dragon will remain attached to the space station's Harmony module for more than four weeks and then splash down in the Pacific Ocean off the coast of Baja California with almost two tons of experiment samples and equipment returning from the station.

ISS Earth Science: Tracking Ocean Winds Panel
Thursday, Sept. 18 (L-2 days): A panel titled ISS Earth Science: Tracking Ocean Winds will be held at Kennedy's Press Site at 6 a.m. PDT (9 a.m. EDT). NASA Television will provide live coverage, as well as streaming Internet coverage.

Participants in the panel will be:

+ Steve Volz, associate director for flight programs, Earth Science Division, Science Mission Directorate, NASA Headquarters

+ Howard Eisen, ISS RapidScat project manager, NASA JPL

+ Ernesto Rodriguez, ISS RapidScat project scientist, NASA JPL

ISS Research And Technology Panel Thursday, Sept. 18 (L-2 days): An ISS Research and Technology Panel will be held at Kennedy's Press Site at 7 a.m. PDT (10 a.m. EDT). NASA Television will provide live coverage, as well as streaming Internet coverage.

Participants in the panel will be:

+ Duane Ratliff, Center for the Advancement of Science in Space (CASIS)

+ Mike Yagley, COBRA PUMA Golf, Director of Research and Testing

+ Dr. Eugene (Gene) Boland, Techshot chief scientist

+ Niki Werkheiser, 3D Printing in Zero-G project manager

ISS Science Panel: Model Organisms
Thursday, Sept. 18, (L-2 days): An ISS Science Panel on model organisms will be held at Kennedy's Press Site at 8 a.m. PDT (11 a.m. EDT). NASA Television will provide live coverage, as well as streaming Internet coverage.

Participants in the panel will be:

+ Marshall Porterfield, division director, Space Life and Physical Sciences, NASA Human Exploration and Operations Mission Directorate (HEOMD)

+ Ruth Globus, project scientist, Rodent Habitat/Rodent Research-1

+ Sharmila Bhattacharya, principal investigator, Ames Student Fruit-Fly Experiment

+ Shiela Neilson-Preiss, principal investigator, Micro-8

+ John Kiss, principal investigator, Seedling Growth-2, University of Mississippi

NASA 'view From The Top' Briefing
Friday, Sept. 19 (L-1 day): A NASA "View from the Top" briefing will be held at Kennedy's Press Site at 6 a.m. PDT (9 a.m. EDT). NASA Television will provide live coverage, as well as streaming Internet coverage.

Participants in the briefing will be:

+ Sam Scimemi, International Space Station division director, HEOMD

+ Jeff Sheehy, senior technologist for the Space Technology Mission Directorate

+ Ellen Stofan, NASA chief scientist

Prelaunch News Conference
Friday, Sept. 19 (L-1 day): The prelaunch news conference will be held at Kennedy's Press Site at 7 a.m. PDT (10 a.m. EDT). NASA Television will provide live coverage, as well as streaming Internet coverage.

Participants in the prelaunch news conference will be:

+ Hans Koenigsmann, VP of Mission Assurance, SpaceX

+ Dan Hartman, International Space Station Program

+ Kathy Winters, launch weather officer, U.S. Air Force 45th Weather Squadron

Post-Launch News Conference
A post-launch news conference will be held at approximately 90 minutes after launch. NASA Television will provide live coverage, as well as streaming Internet coverage.

Participants in the post-launch news conference will be:

+ Dan Hartman, International Space Station Program, Johnson Space Center, Houston

+ Gwen Shotwell, SpaceX president

NASA TV Launch Coverage
Saturday, Sept. 20 (Launch day): NASA TV live coverage will begin at 10:15 p.m. PDT Friday, Sept. 19 (1:15 a.m. EDT Saturday, Sept. 20) and conclude at approximately midnight PDT (3 a.m. EDT). For NASA TV downlink information, schedules and links to streaming video, visit: http://www.NASA.gov/nTV

Audio only of the news conferences and launch coverage will be carried on the NASA "V" circuits, which may be accessed by dialing 321-867-1220, -1240, -1260 or -7135. On launch day, "mission audio," the launch conductor's countdown activities without NASA TV launch commentary, will be carried on 321-867-7135 starting at 10 p.m. PDT (1 a.m. EDT). Launch audio also will be available on local amateur VHF radio frequency 146.940 MHz heard within Brevard County on the Space Coast.

In-Flight NASA TV Coverage
If launch occurs Sept. 20, NASA TV will provide live coverage Monday, Sept. 22, of the arrival of the Dragon cargo ship to the International Space Station. Grapple and berthing coverage will begin at 2:30 a.m. PDT (5:30 a.m. EDT) with grapple at approximately 4:30 a.m. PDT (7:30 a.m. EDT). Berthing coverage begins at 6:30 a.m. PDT (9:30 a.m. EDT).