The countdown begins for the launch of Atlas 5 from Cape Canaveral – Spaceflight Now

Live coverage of the countdown and launch of a United Launch Alliance Atlas 5 rocket from pad 41 at Cape Canaveral Space Force Station in Florida. The mission, known as USSF 12, will launch the US Space Force’s Wide Field of View Testbed satellite and USSF 12 Ring spacecraft into geosynchronous orbit. Text updates will automatically appear below. follow us on Twitter.

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A United Launch Alliance Atlas 5 rocket is ready to propel two US Space Force experimental satellites into geosynchronous orbit on a six-hour mission launched from Cape Canaveral on Thursday. The two-hour launch window opens at 6:00 p.m. EDT (22:00 GMT).

There is a 40% chance of favorable weather as the window opens Thursday in the official launch forecast issued by the Space Force’s 45th Weather Squadron. The forecast improves later in the window, when there is a 60% chance of favorable launch conditions.

The mission, dubbed USSF 12, will be the fourth Atlas 5 flight of the year and the 94th launch of an Atlas 5 rocket overall. It is one of 23 Atlas 5s remaining in ULA’s inventory before the rocket was retired. 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 Force’s Wide Field Of View satellite, or WFOV, Testbed to demonstrate a new infrared sensor capable of detecting and tracking missile launches, providing early warning of an attack potential against the United States of allied nations.

The WFOV spacecraft will travel to space in the upper payload bay of the Atlas 5 rocket. A secondary payload, called USSF 12 Ring, is positioned below the WFOV spacecraft for launch. It hosts several payloads, experiments and prototypes, but the details of their missions are classified.

A Space Force spokesperson told Spaceflight Now that the entire USSF 12 mission, including payloads and launch services, cost approximately $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 Thursday launch began at 10:40 a.m. EDT (2:40 p.m. GMT). ULA crews planned to fire up the Atlas 5 flight computer, complete rocket guidance system checks, and then configure the vehicle for the start of cryogenic refueling around 4 p.m. 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 in the Centaur upper stage burns the propellant mixture of hydrogen and oxygen, and the Atlas first stage burns liquid oxygen with 25,000 gallons of room-temperature kerosene, which was loaded into the rocket on Wednesday, shortly after ULA ground crews rolled the Atlas 5 off the launch pad of the nearby Vertical Integration Facility.

There are two built-in takes in the countdown, one at T-minus 2 hours and another at T-minus 4 minutes, before the final four-minute terminal countdown sequence to prepare for liftoff of the Atlas 5 rocket.

The rocket’s propellant tanks will be pressurized and the RD-180 engine will ignite at T-minus 1 second. After building up thrust on the main engine, the Atlas 5 will send the command to ignite four Northrop Grumman Strap-On Solid Rocket Boosters to supply the Pad 41 launcher with 2.3 million pounds of thrust.

The version of the Atlas 5 launched on USSF Mission 12 is known as the “541” configuration, with the first digit indicating the size of the payload fairing, the second digit representing the number of solid rocket boosters and the third digit the number of engines on the Centaur stage.

The 196-foot-tall (59.7-meter) Atlas 5 rocket, designated AV-094 for this mission, will head east from Cape Canaveral to target the mission’s equatorial orbit more than 22,000 miles away (near 36,000 kilometers) above the Earth.

The Atlas 5 will exceed the speed of sound in 58 seconds, then shed its worn strap boosters at T+ plus 1 minute, 48 seconds. The 5.4-metre-wide (17.7 ft) composite payload fairing will jettison at T+ plus 3 minutes and 25 seconds, and the Russian-made RD-180 mid-stage engine will fire up to T+. + plus 4 minutes and 24 seconds.

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

The USSF 12 mission marks the 100th flight of an RD-180 engine since its first launch in May 2000 on an Atlas 3 rocket.

After separation from the Atlas first stage, ULA’s Centaur upper stage will take over flight with three burns of its single RL10 engine to first place the two Space Force payloads into a parking orbit , then propel the mission into higher orbits and onto a trajectory hugging the Equator.

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

ROCKET: Atlas 5 (AV-094)

ASSIGNMENT: USSF 12

PAYLOAD: WFOV test bed and USSF 12 ring

LAUNCH SITE: SLC-41, Cape Canaveral Space Force Station, Florida

RELEASE DATE: June 30, 2022

LAUNCH WINDOW: 6:00-8:00 p.m. EDT (2200-0000 GMT)

WEATHER FORECAST: 60% chance of having an acceptable time

BOOSTER RECOVERY: None

LAUNCH AZIMUTH: East

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

LAUNCH TIMETABLE:

  • T-00:00:01.0: RD-180 ignition
  • T+00:00:01.0: Takeoff
  • T+00:00:06.9: start of pitch/yaw maneuver
  • T+00:00:57.8: Mach 1
  • T+00:01:07.4: Maximum air pressure (Max-Q)
  • T+00:01:48.4: Solid Rocket Booster Release
  • T+00:03:25.6: Payload fairing jettison
  • T+00:04:24.3: Atlas booster engine shutdown (BECO)
  • T+00:04:30.3: Separation of the Atlas/Centaur floors
  • T+00:04:40.2: Starting Centaur’s first main engine (MES-1)
  • T+00:10:58.2: Centaur First Main Engine Shutdown (MECO-1)
  • T+00:23:13.6: Centaur Second Main Engine Start (MES-2)
  • T+00:28:41.9: Centaur second main engine shutdown (MECO-2)
  • T+05:43:54.1: Centaur Third Main Engine Start (MES-3)
  • T+05:46:20.0: Centaur Third Main Engine Shutdown (MECO-3)
  • T+05:49:36.0: Separation of spacecraft from WFOV test bed
  • T+05:59:03.9: Booster adapter separation
  • T+06:05:21.0: USSF 12 Ring spacecraft separation

MISSION STATS:

  • 676th launch of the Atlas program since 1957
  • Launch of the 377th Atlas from Cape Canaveral
  • 265th mission of a Centaur upper stage
  • 242nd use of the Centaur by an Atlas rocket
  • Launch of the 512th production RL10 engine
  • Launch of the 40th RL10C-1 engine
  • 100th flight of an RD-180 main engine
  • 94th launch of an Atlas 5 since 2002
  • 36th US Air Force/Space Force use of an Atlas 5
  • 14th-17th GEM-63 solid rocket boosters stolen
  • 78th launch of an Atlas 5 from Cape Canaveral
  • 4th launch of Atlas 5 of 2022
  • 136th Evolved Expendable Launcher Flight
  • 151st United Launch Alliance flight overall
  • 86th Atlas 5 under United Launch Alliance
  • 109th United Launch Alliance flight from Cape Canaveral
  • 35th Atlas 5 500 series flight
  • 9th Atlas 5 to fly in 541 configuration
  • 105th launch of Complexe 41
  • The 78th Atlas 5 will use Complex 41
  • 28th total orbital launch from Cape Canaveral in 2022

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