Live coverage of the countdown and launch of the United Launch Alliance’s Atlas 5 rocket from Site 41 of the Cape Canaveral Space Station in Florida. The mission will launch a Boeing Starliner with a human rating during its second unmanned orbital flight test. Text updates will automatically appear below. Follow us on Twitter.
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The countdown to the launch of the United Launch Alliance’s Atlas 5 rocket and Boeing’s Starliner capsule began on Thursday morning at Cape Canaveral. The launch is scheduled for 18:54 EDT (2254 GMT) to begin the second unmanned test flight of the Starliner spacecraft to the International Space Station.
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The Starliner test flight is a precursor to future missions of the capsule crew, owned by Boeing. The spacecraft was developed under the auspices of a multibillion-dollar trade crew agreement with NASA.
But the Starliner program is years late and Thursday’s Orbital Flight Test 2 mission is due to complete the first unmanned test flight in December 2019. Officials canceled the first opportunity to launch the OFT-2 mission last August due to clogged valves. in spacecraft propulsion, adding another nine-month delay to the program.
The Atlas 5 countdown began at 7:34 a.m. EDT (1134 GMT) Thursday with the test rocket computer turned on. Atlas 5 boarded Cape Canaveral Space Station 41 on Wednesday morning from the ULA’s Vertical Integration Facility, about a third of a mile south of the site.
The ULA launch team loaded rocket kerosene in the first phase of the Atlas 5 on Wednesday. The super-cold liquid oxygen will be pumped in the first stage of Atlas 5 during the countdown on Thursday, along with liquid hydrogen and liquid oxygen for the upper Centaur stage.
The ULA has extended the countdown timeline for Starliner missions. The Atlas 5 countdown typically takes about seven hours to launch a satellite. For Starliner missions, the countdown lasts more than 11 hours.
Loading of the first stage of the Atlas 5 and the upper stage of the Centaur with cryogenic propellants will begin about six hours before takeoff at 12:54 EDT (1654 GMT). The built-in T-minus 4-minute countdown, which typically lasts 15 minutes, will last four hours, a change to give astronauts time to board the Starliner spacecraft on crew missions.
The ULA follows the same countdown schedule for the OFT-2 unmanned mission, allowing teams to practice the presence of astronauts on future flights.
A “blue team” of less than 10 Boeing and ULA employees will help astronauts board the Starliner spacecraft during the crew countdown. The work of the team will be similar to the Apollo era closure crew and space shuttles.
During the OFT-2 countdown, the blue team will travel to the launch site and go through their procedures on the day of the launch during the four-hour countdown delay, just as they would if the astronauts were flying. The blue team will close the Starliner hatch and evacuate the site before the countdown resumes. The crew’s access arm will be removed from the Starliner spacecraft about 11 minutes before takeoff.
The countdown clock will then start ticking again at T-minus 4 minutes and the Atlas 5 will switch to internal power, increase the pressure in the fuel tanks and prepare to start the RD-180 main engine.
Departure is scheduled for exactly 18:54:47 EDT (2254: 47 GMT). There is an opportunity to start the day immediately for the OFT-2 mission.
If all goes according to plan, the Starliner spacecraft will arrive at the space station for automated docking at 19:10 EDT (2310 GMT) on Friday. Disembarkation and landing in New Mexico is scheduled for May 25, weather permitting.
The launch of the 172-foot-high Atlas 5 rocket on Thursday will launch a critical test flight. The take-off is scheduled for approximately the moment when the Earth’s rotation brings the launch pad under the flight path of the International Space Station.
The Atlas 5 will launch the 1.6 million-pound pad from its Russian main RD-180 engine and two solid rocket accelerators supplied by Aerojet Rocketdyne. Heading northeast of the Marine Launch Complex, the Atlas 5 will exceed the speed of sound in 65 seconds, then drop its amplifiers at T + plus in 2 minutes and 22 seconds.
The RD-180 engine, which burns kerosene and liquid oxygen, will run up to T + plus 4 minutes and 29 seconds. The RD-180 will be reduced late in its combustion by four and a half minutes to limit the Starliner acceleration load to no more than 3.5 Gs, just as it will be on future astronaut missions.
Six seconds after stopping the engine, the bronze first stage will separate from the upper Centaur of the Atlas 5 to fall into the Atlantic Ocean, after which a disposable aerodynamic coating will be ejected from the nose cone of the Starliner capsule.
Two Aerojet Rocketdyne RL10 engines will start at T + plus 4 minutes and 45 seconds to start a seven-minute burn. A few seconds later, the Atlas 5 will drop the aerodynamic skirt extension under the Starliner spacecraft. The RL10 engines on the Centaur stage will generate 44,600 pounds of thrust to put the Starliner spacecraft on an arcuate, suborbital trajectory.
The configuration of the Atlas 5 rocket for Starliner crew flights is unique from the variant of the launcher used for satellite missions. The Centaur twin-engine upper stage, which once supported older versions of the Atlas rocket, flew only once on the Atlas 5, Starliner’s first test flight in 2019.
The two-engine upper stage has the power to put the Starliner spacecraft at the right altitude and speed, while flying in a flatter and suffocating reverse trajectory, maintaining safe interruption options for astronaut crews during space travel. The flight profile also minimizes g-loads on the Starliner spacecraft and the astronauts inside.
Atlas 5 will launch the Starliner spacecraft nearly 15 minutes after taking off on a 112-mile (181-kilometer) suborbital trajectory, only shy of the speed required to enter a stable orbit around the Earth. Once detached from the rocket, Starliner’s own engines mounted on the ship’s service module will push the spacecraft into orbit to begin the march to the International Space Station.
The suborbital trajectory is unusual for a satellite launch, but is similar to the technique used by the space shuttle. The shuttle’s three main engines, powered by cryogenic propellants from an external fuel tank, accelerated the orbiter into space, reaching speeds slightly lower than required to enter orbit.
After dropping the consumable outer tank, the shuttles activated their engines to maneuver into space about half an hour after launch to enter orbit. Otherwise, the shuttles would suspend their missions and re-enter the atmosphere.
Credit: United Launch Alliance
Starliner will follow a similar launch profile for the OFT-2 mission and subsequent crew flights. The burning of the Starliner in orbit is scheduled to begin about 31 minutes after the mission.
The Atlas 5’s upper Centaur will continue on the suborbital path to re-enter the atmosphere. Debris from the upper stage will hit the Indian Ocean southwest of Australia.
The engines to stop the launch of the Starliner spacecraft will be armed during the space trip on Thursday. During the Boeing OFT-1 mission in 2019, the suspension system operated in “monitor” or “shadow” mode to avoid accidental tripping.
The Atlas 5 missile has an emergency detection system, consisting of two redundant computers, to monitor key health parameters of the launch vehicle. If a safety margin is triggered, Starliner will automatically command termination and the capsule’s emergency engines will push it away from the failed missile.
ROCKET: Atlas 5 (AV-082)
MISSION: Starliner OFT-2
USEFUL LOAD: Starliner spacecraft for Boeing and NASA
LAUNCH PLACE: SLC-41, Cape Canaveral Space Station, Florida
RELEASE DATE: May 19, 2022
STARTING TIME: 18:54:47 EDT (2254: 47 GMT)
WEATHER FORECAST: 80% chance of acceptable weather; The main concern is the cumulus clouds and the anvil
BUSTER RECOVERY: None
START AZIMUTE: Northeast
TARGET ORBIT: Suborbital trajectory when separating a spacecraft with apogee or 112 miles (181 kilometers); Starliner will record in orbit at T + plus for 31 minutes
STARTING TIME:
- T-00: 00: 02.7: RD-180 ignition
- T + 00: 00: 01.1: Takeoff
- T + 00: 00: 06.1: Begin tilt / deviation maneuver
- T + 00: 00: 41.8: Maximum aerodynamic pressure (Max-Q)
- T + 00: 01: 05.8: 1 Mach
- T + 00: 02: 22.0: Missile accelerator ejection
- T + 00: 04: 29.0: Switching off the Atlas booster motor (BECO)
- T + 00: 04: 35.0: Atlas / Centaur stage separation
- T + 00: 04: 41.0: Discard the ascent cover
- T + 00: 04: 45.0 Centaurus’ first main engine (MES-1)
- T + 00: 05: 05.0: Discard the air floor
- T + 00: 11: 54.5: Centaur’s first main engine shutdown (MECO-1)
- T + 00: 14: 54.5: Partition of the Starliner spacecraft
MISSION STATISTICS:
- The 675th launch of the 1957 Atlas program
- 376th launch of the Atlas from Cape Canaveral
- 264th Centaur Upper Stage Mission
- 241st use of the Centaur by the Atlas rocket
- The 510th and 511th RL10 production engines will be launched
- 99th flight of the main engine RD-180
- The 93rd launch of the Atlas 5 in 2002
- 2nd flight of the Starliner spacecraft on the Atlas 5 rocket
- 27th flight of the Atlas 5 rocket in support of a NASA mission
- The 130th and 131st AJ-60 solid rocket accelerators are flying
- 77th launch of the Atlas 5 from Cape Canaveral
- The third launch of Atlas 5 in 2022
- Flight of the 135th evolved launch vehicle
- 150th flight of the United Launch Alliance as a whole
- 85th Atlas 5 from the United Launch Alliance
- 108th flight of the United Launch Alliance from Cape Canaveral
- 2nd Atlas 5 to fly in N22 configuration
- 104th launch from complex 41
- 77th Atlas 5 to use Complex 41
- 21st launch orbit from Cape Canaveral in 2022
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