The Orion spacecraft’s systems are now operating on the ship’s batteries instead of from electrical sources from the launch pad. Unlike it operational versions, this Orion does not carry any solar arrays to provide electrical energy once in space. Since the flight test is 4.5 hours, the batteries will be enough.
Weather Officer Kathy Winters from the 45th Space Wing’s weather squadron just briefed the launch team on weather conditions here are the Cape and updated the official forecast to 70 percent chance of acceptable conditions. They are watching winds and clouds at the time of launch. At this time, all conditions on the Eastern Range are green.
The United Launch Alliance Delta IV Heavy that will lift Orion to an orbit has been loaded with liquid hydrogen fuel and liquid oxygen to power its engines. The Delta IV Heavy uses three core stages bolted together for the first stage. Each core holds about 110,000 gallons of the liquid hydrogen and 40,000 gallons of liquid oxygen for a total load of 330,000 gallons of hydrogen and 120,000 gallons of oxygen. The rocket will turn those super-cold propellants into about 2 million pounds of thrust at liftoff, enough to push the 1.63 million pounds of rocket, spacecraft and fuel straight up into the sky. The second stage uses the same kind of propellants but in much less quantity – 4,500 gallons of liquid oxygen and about 10,000 gallons of liquid hydrogen.
The second stage will make two critical burns during Orion’s mission, the first to get it into an initial orbit of 115 miles by 552 miles, then to push Orion into its high orbit reaching 3,609 miles above Earth. The second stage will separate to leave Orion on its own for re-entry at the end of the mission.
“We haven’t had this feeling in a long time, this feeling of beginning something new – in this case deep space exploration. It’s a new mission and there are some things that we’re going to learn tomorrow from this flight test that we will apply.”
The three core stages of the Delta IV Heavy are venting oxygen as the propellant boils off from its cryogenic liquid state at minus-297 degrees F. The gaseous oxygen is dumped to prevent a pressure buildup inside the tank. The liquid hydrogen also vents as its temperature increases above minus-423 degrees F, but the gaseous fuel is carried away from the rocket before being cast aside. Once the tanks are filled, pumps continue to trickle the propellants into the stages to replace the small amount that boils off.
Today’s launch blog comes to you from Hangar AE at Cape Canaveral Air Force Station in Florida. We are about four miles south of Space Launch Complex 37.
AE is a NASA facility that is probably best known as the communications hub for the agency’s uncrewed missions by the Launch Services Program including the MAVEN and Curiosity missions to Mars among dozens of others. Kennedy Space Center began maintaining the facility in 1960. NASA TV broadcasts launch commentary from here for the LSP missions and today’s on-air coverage also is originating from here.
The Orion spacecraft that sits atop the Delta IV Heavy arrived at Kennedy Space Center in the summer of 2012 so it could be assembled from a pressure vessel into a full-functioning spacecraft. Lockheed Martin built up a factory floor and assembly area for the spacecraft at Kennedy’s Operations and Checkout Building – recently named for humanity’s first moonwalker, Neil Armstrong. Take a look at the steps involved with building a spacecraft and stacking the rocket to set up today’s lift off and flight.
The Mobile Service Tower at Space Launch Complex 37 has been moved away from the launch stand where a United Launch Alliance Delta IV Heavy and Orion spacecraft stand pointed skyward for launch Thursday morning. Weather forecasts continue to call for favorable conditions at launch time and there are no technical concerns reported tonight. Liftoff of Orion’s first flight test is scheduled for 7:05 a.m. EST, the opening of a 2-hour, 39-minute window. Our continuous countdown and mission coverage will begin at 4:30 a.m. EST. NASA TV will begin coverage of the mission at the same time. You can stream NASA TV throughout the countdown and flight of Orion at www.nasa.gov/nasatv.