Countdown Enters Final Built-in Hold

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.

What to Expect from Launch

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.


Fueling Under Way

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.

Photo credit: NASA/Bill Ingalls
Photo credit: NASA/Bill Ingalls

Launch Readiness Review Gives Orion ‘Go’

Managers from United Launch Alliance (ULA) and Lockheed Martin gave a “go” to proceed toward launch pending completion of open work during the Launch Readiness Review for Orion’s flight test. The weather is forecast to be 60 percent “go” for a scheduled liftoff at 7:05 a.m. EST on Thursday, Dec. 4.

NASA TV will air an Orion Flight Test Status and Overview briefing at 1 p.m. today. On Dec. 3, a prelaunch status briefing will be held at 11 a.m. A NASA overview event with participation from social media followers will air at 1 p.m.

How Orion Will Make History

orionvertical-closeupThe Orion spacecraft will take crews farther from Earth than any human-rated spacecraft since Apollo. The first step of that adventure comes this week when the Orion flight test sends an uncrewed version of the capsule about 3,600 miles above Earth – far enough to encounter the high radiation zones that circle the planet and measure their effects on the inside of the spacecraft. On its way back home, Orion’s heat shield will bear the brunt of scorching plasma as the spacecraft dives into the atmosphere at 20,000 mph before slowing for splashdown.

It’s a stress test for more than the spacecraft, of course – people from NASA and Lockheed Martin along with scores of others involved in the program will watch every readout carefully. No matter what happens, the flight test has already made strides in development of America’s next deep-space vehicle for astronauts. Find out all the details of the 4.5-hour mission and what has gone into getting Orion ready for flight in our extensive preview story at

Orion Weather Forecast: 60 Percent ‘Go’

Orionstack-askewWelcome to Launch Week for the Orion Flight Test! Meteorologists issued a forecast this morning calling for a 60 percent chance of acceptable launch conditions Thursday morning for the liftoff of the Orion spacecraft atop a United Launch Alliance Delta IV Heavy rocket. The concern is an expected pattern that could see low clouds and sporadic showers move in from the Atlantic later this week, possibly violating launch criteria designed to prevent the rocket from flying through precipitation. The conditions could also kick up winds too high for a safe liftoff, the forecasters said. Orion will have a 2-hour, 39-minute launch window Thursday. Forecasters are also watching conditions on the West Coast where U.S. Navy ships will gather to retrieve Orion from the Pacific following its 4.5-hour flight. Expected conditions will be favorable according to predictions with no precipitation expected Thursday.

At Space Launch Complex 37, technicians and engineers are finishing closeouts on the Orion/Delta IV Heavy stack and completed work inside the Orion crew module to get everything situated for space. No one will ride aboard Orion, but the spacecraft is carrying numerous sensors to measure conditions throughout the mission, including radiation and temperatures inside the crew module as it reaches 3,600 miles above Earth and then plunges through the atmosphere before opening its chutes and splashing down.