ULA delays Atlas 5 launch to study unexpected engine vibrations – Spaceflight Now

An RL10 engine fires throughout launch of an Atlas 5 Could 18 with the U.S. House Drive’s SBIRS GEO 5 missile warning satellite tv for pc. Credit score: United Launch Alliance

United Launch Alliance’s subsequent Atlas 5 launch will carry Boeing’s Starliner crew capsule into July 30 on its second unpiloted combat, officers confirmed Thursday. An Atlas 5 rocket for the U.S. army beforehand scheduled for June 23 has been postponed as engineers analyze surprising vibrations of a brand new higher stage engine nozzle on a mission final .

The Atlas 5 rocket slated to launch the Starliner check flight makes use of two-engine Centaur higher stage utilizing a distinct model of the Aerojet Rocketdyne RL10 engine. A brand new RL10 engine variant debuted on the newest Atlas 5 launch Could 18.

The Centaur higher stage’s single upgraded RL10C-1-1 engine accomplished two profitable firings on the Could 18 mission to deploy the U.S. House Drive’s SBIRS GEO 5 missile warning satellite tv for pc into orbit.

However engineers are taking additional time to analyze surprising vibrations of the RL10C-1-1 engine’s new nozzle extension throughout final ’s launch, in keeping with Tory Bruno, ULA’s president and CEO. On-board video from the launch confirmed the nozzle vibrating, or “ringing,” quickly it ignited about 5 minutes after liftoff.

“These watching the stay feed might have noticed some ringing of RL10s’s new carbon nozzle extension,” Bruno tweeted. “Whereas it did its job, boosting RL10’s eye watering efficiency even a bit larger, we need to be sure that we totally perceive that earlier than flying this configuration once more.”

The upgraded RL10C-1-1 engine comes with a efficiency enchancment and is simpler to construct, in keeping with ULA.

The Centaur higher stage for the Starliner’s Orbital Flight Check-2 mission. An aeroskirt on the prime of the Centaur will hook up with the Starliner capsule. Credit score: United Launch Alliance

The RL10C-1-1 engine has a bigger nozzle than the flown on earlier Atlas 5 rockets, and introduces a brand new 3D-printed injector, which is flying on its first operational mission, stated Gary Wentz, vp of presidency and industrial packages at ULA, throughout a press briefing earlier than the SBIRS GEO 5 launch final month.

In accordance with Aerojet Rocketdyne’s web site, the RL10C-1-1 engine produces about 1,000 kilos of extra thrust over the RL10C-1 engine model used on earlier Atlas 5 rockets.

Greater than 500 RL10 engines have flown on rockets because the 1960s. ULA’s Vulcan Centaur rocket will even use the RL10C-1-1 engine variant, as will all future Atlas 5s besides missions with Boeing’s Starliner crew capsule, which makes use of a singular dual-engine Centaur higher stage.

The dual-engine Centaur is powered by RL10A-4-2 engines, an older variant of the RL10 with out the carbon nozzle extension.

The U.S. army’s House Check Program-3, or STP-3, mission was subsequent on ULA’s launch schedule. The STP-Three mission was scheduled for launch June 23 with a number of army spacecraft heading into a geosynchronous orbit greater than 22,000 miles (almost 36,000 kilometers) over the equator.

One of many satellites on the STP-Three mission, named STPSat 6, hosts a number of payloads and experiments, together with the Nationwide Nuclear Safety Administration’s House and Atmospheric Burst Reporting System-Three payload, which is designed to detect nuclear from orbit. NASA’s Laser Communications Relay Demonstration experiment and several other extra payloads are additionally flying on the STPSat 6 spacecraft.

A smaller satellite tv for pc named LPDE 1 will journey into orbit with STPSat 6. The LPDE 1 spacecraft is designed to accommodate experimental payloads and small satellites, which might be deployed from the guardian satellite tv for pc in orbit.

The STP-Three mission will launch on an Atlas 5 rocket flying within the “551” configuration with 5 strap-on boosters, a 5.4-meter (17.7-foot) diameter payload fairing, and a single RL10C-1-1 engine on the Centaur higher stage.

An Atlas 5 rocket lifts off Could 18 from pad 41 at Cape Canaveral House Drive . Credit score: United Launch Alliance

ULA final week introduced the delay within the STP-Three mission to research the engine nozzle vibrations. The corporate, a 50-50 three way partnership between Boeing and Lockheed Martin, confirmed Thursday that the Starliner check flight, utilizing the older RL10 engine variant, will launch forward of the STP-Three mission.

The Starliner’s second unpiloted check flight is a redo of an indication mission in December 2019 that failed to achieve the Worldwide House Station. Boeing and NASA officers the botched check flight on software program points, and the reusable capsule safely landed in New Mexico after mission management aborted the mission to the house station.

Developed with greater than $5 billion in NASA funding, Boeing’s Starliner spacecraft is designed to ferry astronauts to and from the house station. NASA has a contract with Boeing for no less than six Starliner crew rotation flights to the house station, giving the company a second U.S. automobile for astronaut missions to low Earth orbit, following the beginning of operational service with SpaceX’s Crew Dragon capsule final yr.

The Starliner mission for launch July 30, often known as Orbital Flight Check-2, is a prerequisite to the Boeing crew capsule’s first check flight with astronauts. The OFT-2 mission is anticipated to final between 4 and eight days, in keeping with Joel Montalbano, NASA’s program supervisor for the Worldwide House Station.

Three astronauts will dock with the house station on the Starliner’s Crew Flight Check.

After the Crew Flight Check, NASA will certify the Starliner to fly on operational crew rotation missions to the house station. These flights will carry 4 astronauts and last as long as seven months.

E mail the writer.

Comply with Stephen Clark on Twitter: @StephenClark1.

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