The countdown to the launch of the Atlas 5 from Cape Canaveral – Spaceflight Now – has begun

Live coverage of the United Launch Alliance’s Atlas 5 rocket countdown and launch from Site 41 of the Cape Canaveral Space Station in Florida. The mission, known as USSF 12, will launch a geosynchronous orbiting satellite of the US space force and the USSF 12 Ring spacecraft. Text updates will automatically appear below. Follow us in Twitter.

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The United Launch Alliance’s Atlas 5 rocket is ready to launch two experimental satellites of the US space forces all the way to geosynchronous orbit in a six-hour mission launched from Cape Canaveral on Thursday. The two-hour start window opens at 18:00 EDT (2200 GMT).

There is a 40% chance of favorable weather when the window opens on Thursday in the official launch forecast issued by the 45th Meteorological Squadron of the Space Forces. The forecast improves later in the window when there is a 60% chance of favorable start-up conditions.

The mission, codenamed USSF 12, will be the fourth Atlas 5 flight of the year and the 94th launch of the Atlas 5 rocket overall. This is one of the 23 Atlas 5s left in the ULA’s inventory before the missile was withdrawn. ULA, a 50-50 joint venture between Boeing and Lockheed Martin, is developing the next generation Vulcan Centaur rocket to replace the Atlas and Delta rocket families.

One of the mission’s payloads is the Space Forces’ Wide Field Of View, or WFOV, satellite to demonstrate a new infrared sensor capable of detecting and tracking rocket launches, providing early warning of a potential attack on the United States by Allied nations.

The WFOV spacecraft will travel to space at the top of the cargo compartment of the Atlas 5 rocket. A secondary payload, called the USSF 12 Ring, is located below the WFOV spacecraft for launch. It hosts many payloads, experiments and prototypes, but the details of their missions are classified.

A space force spokesman told Spaceflight Now that the entire USSF 12 mission, including payloads and launch services, cost about $ 1.1 billion.

ULA’s Atlas 5 rocket on the launch pad before the USSF 12 mission. Credit: United Launch Alliance

The countdown to the start on Thursday began at 10:40 a.m. EDT (1440 GMT). ULA teams planned to turn on the Atlas 5 flight computer, complete inspections of the missile guidance system, and then configure the vehicle to begin cryogenic tanking around 16:00 EDT (2000 GMT).

Nearly 66,000 gallons of liquid hydrogen and liquid oxygen will be loaded into the two-stage Atlas 5 rocket. The Aerojet Rocketdyne RL10 engine on the Centaur’s upper stage burns a mixture of hydrogen and oxygen, and the first stage of the Atlas consumes 25,000 gallons of liquid kerosene fuel at room temperature. temperature, which was loaded into the rocket on Wednesday, shortly after ULA ground crews rotated the Atlas 5 launch pad from a nearby vertical integration facility.

In the countdown, two built-in delays are planned, one at T-minus 2 hours and another at T-minus 4 minutes, before the last four-minute countdown sequence of the terminal to prepare for the takeoff of the Atlas 5 rocket.

The rocket’s fuel tanks will be pressurized and the RD-180 engine will start at T-minus 1 second. After increasing the thrust of the main engine, the Atlas 5 will send a command to ignite four rocket accelerators to Northrop Grumman with a belt to power the launch pad from site 41 with 2.3 million pounds of thrust.

The version of the Atlas 5, which launched on the USSF 12 mission, is known as configuration “541”, the first number indicates the size of the fairing fairing, the second number represents the number of the rocket accelerator on solid fuel, and the third digit is the number of engines. the Centaur scene.

The 196-foot (59.7-meter) Atlas 5 rocket, designed by AT AV-094 for this mission, will head east from Cape Canaveral to steer the mission’s equatorial orbit more than 22,000 miles (nearly 36,000 kilometers). ) above the Earth.

The Atlas 5 will exceed the speed of sound in 58 seconds, then discard its depleted amplifiers at T + plus 1 minute and 48 seconds. The 5.4-meter (17.7-foot) combined payload will be ejected at T + plus 3 minutes, 25 seconds, and the Russian RD-180 engine will run up to T + plus 4 minutes and 24 seconds.

This graph illustrates the components of the Atlas 5 missile for the USSF 12 mission. Credit: United Launch Alliance

The USSF 12 mission marks the 100th flight of an RD-180 engine since it was first launched in May 2000 with an Atlas 3 rocket.

Following the separation of the first phase of the Atlas, ULA’s upper Centaur stage will take over the three-burn flights of its single RL10 engine to first place the two Space Forces payloads in parking orbit and then move the mission into higher orbits. and along a trajectory embracing the equator.

The WFOV Testbed spacecraft, built by Millennium Space Systems, will separate from the upper stage of the Centaur at T + plus 5 hours and 49 minutes. An adapter structure will be released about 10 minutes later, revealing the payload USSF 12 Ring built by Northrop Grumman for separation at T + plus 6 hours and 5 minutes.

ROCKET: Atlas 5 (AV-094)


PAYLOAD: WFOV Test Bench and USSF 12 Ring

STARTING SITE: SLC-41, Cape Canaveral Space Station, Florida

STARTING DATE: June 30, 2022

STARTING WINDOW: 18: 00-8: 00 EDT (2200-0000 GMT)

WEATHER FORECAST: 60% chance of acceptable time



TARGET ORBIT: Approximately 22,440 miles, 0.0 degree incline


  • T-00: 00: 01.0: RD-180 ignition
  • T + 00: 00: 01.0: Takeoff
  • T + 00: 00: 06.9: Start a slope / deviation maneuver
  • T + 00: 00: 57,8: 1 Mach
  • T + 00: 01: 07.4: Maximum aerodynamic pressure (Max-Q)
  • T + 00: 01: 48.4: Missile accelerator ejection
  • T + 00: 03: 25.6: Disposal of the fairing fairing
  • T + 00: 04: 24.3: Switching off the Atlas booster motor (BECO)
  • T + 00: 04: 30.3: Atlas / Centaur stage separation
  • T + 00: 04: 40.2: First start of Centaur’s main engine (MES-1)
  • T + 00: 10: 58.2: First shutdown of Centaur’s main engine (MECO-1)
  • T + 00: 23: 13.6: Start of Centaur’s second main engine (MES-2)
  • T + 00: 28: 41.9: Shutdown of Centaur’s second main engine (MECO-2)
  • T + 05: 43: 54.1: Start of Centaur’s third main engine (MES-3)
  • T + 05: 46: 20.0: Shutdown of Centaur’s third main engine (MECO-3)
  • T + 05: 49: 36.0: WFOV Spaceship test bench
  • T + 05: 59: 03.9: Separation of the amplifier adapter
  • T + 06: 05: 21.0: USSF 12 ring-shaped spacecraft separation


  • The 676th launch of the 1957 Atlas program
  • 377th launch of the Atlas from Cape Canaveral
  • 265th mission on the upper stage of Centaur
  • 242nd Centaur use of the Atlas rocket
  • The 512th series RL10 engine will be launched
  • The 40th RL10C-1 engine was launched
  • 100th flight of the main engine RD-180
  • The 94th launch of the Atlas 5 in 2002
  • The 36th US Air Force uses the Atlas 5
  • 14-17th GEM-63 solid rocket accelerators fly
  • The 78th launch of the Atlas 5 from Cape Canaveral
  • 4th launch of Atlas 5 in 2022
  • Flight of the 136th evolved launch vehicle
  • 151st United Launch Alliance flight as a whole
  • 86th Atlas 5 from the United Launch Alliance
  • 109th flight of the United Launch Alliance from Cape Canaveral
  • 35th flight of the 500 series of Atlas 5
  • The 9th Atlas 5 will fly in configuration 541
  • 105th launch from complex 41
  • 78th Atlas 5 to use Complex 41
  • The 28th total orbital launch from Cape Canaveral in 2022

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