The planned crew launch of Boeing’s Starliner space shuttle

Atlas 5 rocket carries astronauts The blast was first triggered on Monday night Boeing’s long-delayed Starliner crew ferry In orbit for its first pilot test flight. But a problem with a valve in the rocket’s upper stage forced mission managers to order a scrub two hours before liftoff.

It was a disappointment for the commander Barry “Butch” Wilmore and co-pilot Sunita Williams, who were on strapping duty for the launch when the scrub was announced. The moment brought to mind one of Wilmore’s favorite sayings, “You’d rather be on the ground than you’d be in space.”

It’s not immediately clear when Boeing and rocket-builder United Launch Alliance will be able to mount another attempt, but engineers must first figure out what caused the rocket’s Centaur upper stage oxygen relief valve to “chatter” in the late stages. Fuel and what might be needed to fix it.

After the countdown to launch, the Atlas 5 rocket and Starliner crew capsule were aborted due to problems with the upper stage oxygen relief valve. The release is now on hold pending resolution of the valve issue.

NASA TV


Years behind schedule and more than a billion dollars spent, Starliner is Boeing’s answer to SpaceX’s Crew Dragon, an already operational shuttle that carried 50 astronauts, astronauts and civilians into orbit on 13 flights, 12 of them to the space station.

NASA funded the development of both shuttles to ensure the agency could send personnel to the outpost even if a company’s shuttle was grounded for any reason. Although Boeing took longer than expected to prepare their ship for crew flights, all systems were launched from Pad 41 at the Cape Canaveral Space Force Station at 10:34 pm EDT.

Engineers were busy loading the propellant when the valve problem was discovered. After evaluating its performance, engineers could not be “comfortable” with its behavior and the launch was aborted.

Decked out in Boeing’s dark blue pressure suits, Wilmore and Williams, both veteran Navy test pilots and active-duty astronauts with four previous space missions, stepped out of the Starliner and began waiting for another chance to launch. .

Sunita Williams, left, and Commander Butch Wilmore exit the Starliner capsule shortly after launch and are escorted back to the crew cabin at Kennedy Space Center.

NASA TV


Atlas 5, making its 100th flight, is the most reliable rocket with a perfect launch record. The rocket is equipped with a sophisticated emergency fault detection system and the Starliner, like SpaceX’s Crew Dragon, has a “full envelope” abort system for the launch pad to orbit.

Whenever it takes off, Atlas 5 needs only 15 minutes to lift the Starliner into an initial orbit. Once in space, the astronauts will conduct two quick thrust firings to fine-tune the spacecraft’s orbit before testing the spacecraft’s computer-aided manual control system.

As with other space station rendezvous, Starliner will approach the laboratory from behind and below, circle to a point directly at the outpost, and then move to dock in the forward port of the Harmony module.

During final approach, Wilmore and Williams will again test the capsule’s manual controls to ensure that future crews will be able to modify the trajectory or orientation of the spacecraft at will if necessary.

The Starliner is equipped with a fully manual backup system that bypasses the spacecraft’s flight computers and allows the crew to directly command the ship’s thrusters using a joystick-like hand controller. Wilmore and Williams will test the system after leaving the station on May 15 and begin their journey back to Earth.

Four space missions between Starliner Commander Barry “Butch” Wilmore and Copilot Sunita Williams, two veteran Navy test pilots and NASA astronauts.

NASA


Once at the dock, Wilmore and Williams will spend more than a week with the station’s seven long-term crew members: astronauts Oleg Kononenko, Nikolai Chubb and Alexander Grebenkin, along with NASA’s Matthew Dominik, Michael Barrett, Jeanette Epps and Tracy Dyson.

If the Starliner test flight goes well, NASA managers expect certification for regular crew rotation flights, launching a Crew Dragon and a Starliner each year to deliver long-duration crew members to the station for six-month missions.

“Absolutely Important Milestone”

Jim Free, NASA’s associate administrator for space operations, called the Starliner Crew Flight Test, or CFT, “an absolutely critical milestone.”

“I remind everyone again, this is a new spacecraft,” he told reporters last week. “There are definitely things we don’t know about this mission, and we might encounter things we don’t expect. But our job right now is to be vigilant and look for problems.”

While he said he believed the Starliner would accomplish the mission, Frei said he didn’t want to “get too far ahead” because the crew had yet to complete a successful mission. But “when we do,” he added, “when we certify Starliner, the United States will have two unique human space shuttles that will provide critical redundancy for ISS access.”

But it wasn’t easy.

After the retirement of the Space Shuttle in 2011, NASA awarded two commercial group project contracts in 2014 to promote the development of an independent spacecraft capable of carrying astronauts. International Space Station.

The target date for the first piloted CCP flights is 2017. Congressional funding shortfalls and technical glitches have delayed development, including an explosion during a ground test that destroyed the SpaceX Crew Dragon.

But the California rocket builder finally began pilot flights in May 2020, successfully launching two NASA astronauts aboard the Crew Dragon test flight to the space station.

Since then, SpaceX has launched eight mission crew orbiters to the station, three research missions to the Houston-based lab. Axiom Space and A Purely commercial, a two-man, two-woman trip to low-Earth orbit by billionaire pilot and entrepreneur Jared Isaacman. In total, 50 people have flown into orbit in Crew Dragons.

It’s a different story for Boeing’s Starliner.

During an unmanned test flight in December 2019, a software error prevented the ship’s flight computer from loading the correct launch time from the Atlas 5 ship.

The Starliner capsule and its service module are attached to the Atlas 5 booster’s slender Centaur upper stage for launch. The drum-shaped extension below the service module is an “aeroskirt” designed to improve aerodynamics during ascent from the thick lower atmosphere.

United Publishing Alliance


As a result, the required orbital insertion burn did not happen on time and due to unrelated communication problems, the flight controllers were unable to regain control in time.

The software problems were resolved after the Starliner landed, along with various issues that came to light in the post-flight review. Boeing chose to conduct a second test flight at its own expense, but the company found the propulsion system valves in the Starliner’s service block stuck. Engineers were unable to resolve the problem and the capsule was removed from its Atlas 5 and transported back to its processing facility for repairs.

Engineers eventually identified a moisture problem, presumably high humidity and rain after the pad was rolled, which chemically reacted with the thruster propellant and created corrosion. Corrosion prevented the valves from opening on command.

To clear the way for a launch next May, valves in the new service module were replaced and the system modified to prevent water from entering the launch pad. A second Starliner test flight in May 2022 was successful, docking with the space station as planned and returning to Earth with a precision landing.

But after the flight, engineers discovered new problems: trouble with the parachute harness connectors and concern about the protective tape wrapped around the wiring that could catch fire on short circuits.

Work to fix those problems pushed the first flight from 2023 to 2024. After all was said and done, Boeing spent more than $1 billion of its own money to pay for additional test flights and corrective actions.

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