SpaceX

At launch time, the International Space Station will be flying 261 miles above the middle of the Indian Ocean.

The terminal count is under way with 10 minutes left in the countdown.

Launch Director Brian Childers and Launch Conductor Ricky Lim have given the team the go-ahead to begin the terminal count at 4:37 a.m., 10 minutes prior to launch. At that point, the Falcon 9 and Dragon autosequences will carry out all rocket and spacecraft commands automatically.

The Falcon 9 rocket is backdropped by the darkness of a predawn sky at Cape Canaveral Air Force Station’s Space Launch Complex 40.

With less than 30 minutes remaining until the planned 4:47 a.m. liftoff of the SpaceX Falcon 9 rocket, the countdown continues to go smoothly and activities are on schedule at Space Launch Complex 40 at Cape Canaveral Air Force Station.

Consoles across the country are active right now for the SpaceX CRS-5 mission. From the SpaceX Launch Control Center in Cape Canaveral, the company manages the countdown and liftoff. Meanwhile, SpaceX Mission Control located at the company’s Hawthorne, Calif. headquarters also is staffed with controllers ready to support the flight. And NASA’s Mission Control Center at Johnson Space Center in Houston is participating due to the Dragon’s destination: the International Space Station.

One of the payloads destined for the International Space Station is the Cloud-Aerosol Transport System, or CATS. It’s a remote-sensing instrument that relies on lidar technology – similar to a radar, but using a laser instead of sound – to study the location, makeup and distribution of aerosols, pollution, dust, smoke and other particulates in Earth’s atmosphere. To learn more about CATS, view the replay of last week’s briefing from Kennedy Space Center:

Weather continues to look good and the 90 percent “go” prediction remains in effect, according to Launch Weather Officer Mike McAleenan of the 45th Weather Squadron.

“We are ‘go’ on all range weather and Falcon 9 weather criteria,” McAleenan told controllers during a briefing that began one hour before liftoff time. “Just a 10 percent chance of Thick Cloud Rule violation.”

The forecast calls for scattered clouds and good visibility, with a temperature of about 50 degrees F at the 4:47 a.m. launch time.

The 157-foot-tall Falcon 9 was lifted to vertical last night. The strongback – a gantry-like tower providing support and umbilicals – is in place beside it at Space Launch Complex 40. The strongback will be lowered late in the countdown to clear the way for the departing rocket.

At this time, both the rocket and spacecraft are powered. The Falcon 9’s nine first-stage Merlin 1D engines and single second-stage Merlin vacuum engine are powered by liquid oxygen (LOX) and a refined kerosene fuel called RP-1. Loading of RP-1 began at 1:47 a.m., followed by the start of LOX loading at 2:12. As the cryogenic liquid oxygen warms up, some of it boils off as gaseous oxygen and is vented away from the rocket during the countdown. Topping-off of liquid oxygen will continue until late in the countdown, replacing what boils away.

This flight will be the 14th for the Falcon 9, a rocket named after the famed Millennium Falcon in Star Wars. No word on whether the Falcon 9 has made the Kessel Run in less than 12 parsecs.

The Dragon spacecraft is set to deliver more than 5,000 pounds of cargo to the International Space Station on CRS-5. Food, supplies and care packages for the station crew are on board, along with spacewalk equipment, Russian hardware and Japan Aerospace Exploration Agency equipment, and vehicle hardware supporting several critical station systems, including the electrical power system and the Environmental Control and Life Support system.

Dragon also is carrying critical materials to support 256 science and research investigations that will occur during Expeditions 42 and 43. Studies conducted at the station benefit people on Earth as well as future explorers embarking on long-duration missions. During a briefing early last week at Kennedy Space Center, scientists and researchers discussed the studies headed for the station on this flight, such as research on the risks of in-flight infections in astronauts, as well as research on degenerative brain diseases such as Alzheimer’s. View the briefing here: