The Centaur upper stage main engine has started its first burn following on-time booster engine cutoff and Atlas/Centaur separation. This first of two burns for the Centaur main engine start will last nearly 14 min. The payload fairing jettisoned, giving TDRS-M its first exposure to the space. All vehicle systems are performing well.
Booster ignition and liftoff of the United Launch Alliance Atlas V rocket to deliver the TDRS-M spacecraft to join the Tracking and Data Relay Satellite System, a critical communications link between ground stations and Earth-orbiting spacecraft including the International Space Station and Hubble Space Telescope.
The vehicle will pass Mach 1 about a minute after launch, followed by Max Q, the area of maximum dynamic pressure.
About four minutes into the flight, a series of key events occurs in rapid succession: Atlas booster engine cutoff, separation of the booster from the Centaur, ignition of the Centaur main engine for its first of two burns, then jettison of the payload fairing.
During these last four minutes of the countdown, the Atlas and Centaur propellant tanks will be brought up to flight pressure and the Eastern Range and launch managers will perform final status checks.
The soonest the Atlas V rocket and TDRS-M spacecraft could launch this morning is 8:18 a.m. EDT. Managers and engineers continue to evaluate the Centaur liquid oxygen chilldown system and expect it may take a few more minutes and go beyond that time, although temperatures are trending in the right direction. The launch window extends to 8:43 a.m.
Launch managers are extending the T-4 minute hold for an additional five minutes as the team evaluates a technical issue regarding the the Centaur upper stage’s liquid oxygen chilldown system. Conditions are trending in the right direction, according to NASA Launch Commentator Mike Curie. Today’s launch window extends to 8:43 a.m. EDT.
The Atlas family of rockets boasts a solid track record, and today’s launch will mark the 72nd for the Atlas V vehicle. The rocket standing on the pad at Space Launch Complex 41 is an Atlas V 401 configuration, used in more than half of the Atlas V launches to date. The 401 designation means this rocket has a 4-meter-wide payload fairing, no solid rocket boosters, and a single engine on its Centaur upper stage.
The first two satellites in the current TDRS series – TDRS-K and TDRS-L, launched in January 2013 and January 2014, respectively – both launched from the same launch complex on the same variant of the Atlas V.
The Atlas first-stage booster is powered by a dual-nozzle RD-180 engine, which ignites at T-0. Above the booster is the Centaur upper stage with its single RL10 engine. The two-piece payload fairing that protects the TDRS-M satellite tops the vehicle.
Built by Boeing at its factory in El Segundo, California, TDRS-M is the final in a series of three third-generation satellites to join the TDRS constellation. This generation will improve the system’s coverage flexibility as well as its ability to support more data and increased transmission rates.
Photo at right: Inside the Astrotech facility in Titusville, Florida, NASA’s Tracking and Data Relay Satellite, TDRS-M, undergoes final checkouts prior to encapsulation in its payload fairing. Photo credit: NASA/Glenn Benson
Countdown clocks are holding at the T-4 minute mark. This is a planned hold scheduled to last 15 minutes.
In his briefing to the launch team just minutes ago, Launch Weather Officer Clay Flinn with the U.S. Air Force 45th Weather Squadron reported light winds and temperatures in the low 80 degrees Fahrenheit. Weather remains projected to be 90 percent “go” at launch time, 8:03 a.m. EDT.
Good morning from Florida’s Space Coast! Our coverage is just beginning for the scheduled liftoff of a United Launch Alliance Atlas V rocket carrying NASA’s newest addition to the dependable Tracking and Data Relay Satellite System.
The Atlas V rocket and its TDRS-M payload are in place at Space Launch Complex 41 on Cape Canaveral Air Force Station in Florida, where countdown clocks are steadily moving toward liftoff at 8:03 a.m. EDT, the beginning of a 40-minute launch opportunity. The weather forecast predicts a 90 percent chance of favorable weather.
Launch managers and controllers have been on console in the Atlas Spaceflight Operations Center since about 1 a.m. and operations to load the Atlas booster with liquid oxygen and the Centaur upper stage with liquid oxygen and liquid hydrogen began less than two hours ago. The booster’s rocket-grade kerosene fuel, RP-1, was loaded Wednesday.
A weather briefing is coming up in just a few minutes, and a 15-minute built-in hold starts at 7:44 a.m. when the countdown reaches the T-4 minute mark.
The countdown is underway for today’s planned liftoff of a United Launch Alliance Atlas V rocket with NASA’s Tracking and Data Relay Satellite-M (TDRS-M). Launch from Cape Canaveral Air Force Station’s Space Launch Complex 41 is scheduled for 8:03 a.m. EDT at the opening of a 40-minute launch window.
Launch coverage will begin at 7:30 a.m. right here and on NASA TV.