Orion has 2 hours and 39 minutes to lift off today on its flight test.
The launch conductor extended the countdown hold because of the range hazard and due to a second stage propellant conditioning issue.
19 minutes before launch and the countdown entered a built-in hold as planned. There are no weather or technical impediments to liftoff at 7:05 a.m. EST. This pause will last 15 minutes and allow the launch and flight teams to conduct their polling to give the final go-aheads to begin the Orion mission. The countdown will resume at the T-4 minute mark at 7:01 a.m. and it will mark the start of the terminal countdown phase, the last before liftoff. Today’s launch window extends to 9:44 a.m.
We are moving through this morning’s countdown and everything remains on track for a liftoff at 7:05 a.m. EST, including the weather. We’ll have the final launch forecast shortly, followed by a 15-minute built-in hold at T-4 minutes that will set the stage for the terminal countdown phase.
Launch polls will be conducted during this hold to clear the way for liftoff. Orion will switch over to its own battery power then the final “go/no-go” call will be made. After that, the Delta IV’s three core stage engines will ignite and rev up to 2 million pounds of thrust.
The Delta IV Heavy and Orion will clear the tower in just a few seconds to begin a carefully choreographed climb skyward. The core stages on either side of the rocket will burn their propellants and fall away at T+3minutes, 56 seconds. The central core stage will continue for another 94 seconds as the rocket and spacecraft climb higher and pick up more speed. The first stage will fall away and the second stage will take over to put Orion into an initial orbit of 115 miles by 552 miles.
“We intend to stress the systems. This is set up to be a test flight, to learn those risky things when there are not people aboard.”
United Launch Alliance operates the Delta IV Heavy, the largest rocket in the American launch inventory. The first stage of the Delta IV Heavy includes three core stages, each one 134-feet-tall and 16.7 feet in diameter. An RS-68 engine is at the base of each core stage to give the rocket a combined thrust of about 2 million pounds. The stage holds super-cold liquid oxygen and liquid hydrogen propellants. The second stage of the Delta IV Heavy is powered by a single RL10B-2 engine that also uses a combination of liquid hydrogen and liquid oxygen. The Orion spacecraft is bolted to the top of the second stage.
The Spaceflight Meteorology Group at Johnson says the weather looks good off the coast of Baja California where Orion will descend and splashdown later this morning to end the flight test. Navy ships are waiting in the area to recover the Orion spacecraft.
The teams of engineers and flight controllers that will conduct Orion’s flight test took their places about an hour ago at consoles here at Cape Canaveral and at Houston’s Mission Control Center at Johnson Space Center. Everything from system checkouts and confirmations to the fueling process is done remotely by the controllers since no one is allowed at the launch pad during this final phase of the countdown. Once Orion leaves the launch pad, Mission Control takes over as it did during Space Shuttle missions.
Good morning from Florida, and welcome to our continuous coverage of the countdown, launch and flight of the Orion spacecraft on its first flight test. We are 2 hours and 5 minutes from the launch of Orion on a Delta IV Heavy rocket, the largest rocket in America’s current inventory.
There are no technical problems reported or being worked at this time and the weather forecast still calls for a 70 percent chance of acceptable conditions when our launch window opens at 7:05 a.m. EST. Between now and then, we will let you know as the Orion launch and mission control teams pass key milestones. We’ll also give you some context for what this mission means to Orion’s development and to the nation’s ambitions to send astronauts on deep space exploration missions in the future, including eventual flights to Mars.
Stick with us throughout the mission, too, because we’ll be here through Orion’s Pacific Ocean splashdown about 4.5 hours after launch.
Preparations for Orion’s flight test are progressing smoothly ahead of a scheduled 7:05 a.m. EST liftoff today. United Launch Alliance has begun fueling the Delta IV Heavy rocket with liquid hydrogen and liquid oxygen. Weather remains forecast to be 70 percent “go” at the time of liftoff. Today’s launch will take place from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. The spacecraft will splashdown in the Pacific Ocean at the end of the flight.