Boeing said Monday it had rehabilitated a program for the company’s Starliner crew capsule after programming bugs led to the spacecraft’s first orbital test flight in 2019, and technicians at the Kennedy Space Center delivered the crew and service units for the next unmanned test flight of the Starliner. To the International Space Station in March.
NASA and Boeing officials officially target March 29 for a second Starliner Orbital Flight test, a repeat of the first test flight in 2019, when software problems prevented the capsule from docking with the space station. Boeing and NASA managers agreed last year to resend the OFT mission to show a full sequence of Starliner flights before the spacecraft was freed for the astronauts.
The Starliner landed safely in New Mexico, but engineers set out to review all of the spacecraft software codes to prevent problems from recurring on the first OFT mission.
Several NASA and industry officials said the OFT-2 mission launch could advance to around March 25. Boeing’s Starliner missions launched on United Launch Alliance Atlas 5 missiles from Cape Canaveral Space Force Station, and the capsule lands under parachutes at one of several locations in the western United States.
The OFT-2 mission will lay the groundwork for the next Starliner test flight to transport three NASA astronauts to the space station later this year, followed by the start of the crew’s periodic flights.
Boeing said Monday that engineers have completed a “full review” of the Starliner program. The company said teams have also evaluated the qualification process for future modifications and upgrades for the program.
“The work this team has done in comprehensively unpacking our software is a defining moment for the program,” said John Vollmer, Starliner’s vice president and program director, in a statement. “We are smarter as a team through this process, and most importantly, we are smarter as a human spaceflight community.”
Meanwhile, a Boeing spokesman said technicians inside NASA’s Kennedy Space Center’s commercial crew equipping and cargo facility mated with crew and service units last week on the OFT-2 mission, a milestone in preparing the spacecraft for launch.
Assuming the OFT-2 mission continues with a launch date of about March 25, Boeing teams will load the Starliner with highly maneuverable propellant next month before transporting the capsule to the Atlas 5 launch pad.
One of the hardware changes for the OFT-2 mission is the installation of a new docking system cover on the front of the Starliner crew unit. Designed to better protect sensitive docking port components during re-entry heat, the door will help ensure that Starliner crew units can be reused at least 10 times, depending on the spacecraft’s design specifications.
The door will open once the Starliner reaches orbit, revealing the docking interface for the spacecraft to communicate with the space station. After decoding, the door will close for re-entry. The cover is similar in purpose to the conical door of SpaceX’s Crew Dragon spacecraft.
Boeing plans to alternate between two reusable crew units for all planned Starliner missions. Each flight will use a new service unit that provides propulsion and power generation capacity for the spacecraft. The crew unit from the OFT-1 mission is being revamped for Boeing’s Crew Test flight and is Starliner’s first astronaut mission.
NASA awarded contracts to Boeing and SpaceX in 2014 to develop Starliner and Crew Dragon spaceships to transport astronauts to and from the space station. Both programs faced technical delays, but SpaceX successfully launched its first two crew missions – a test flight and the first operational crew rotation mission – last year, restoring orbiting human spaceflight capacity to the United States for the first time since the end of the Space Shuttle program in 2011.
The start of operating flights with Boeing’s Starliner in the United States will give two independent spacecraft designs capable of carrying crews into low Earth orbit for the first time in the history of the space program.
Boeing said the software rehab milestone is paving the way for a comprehensive simulation of the OFT-2 test flight at the company’s avionics and software integration lab in Houston. Boeing said the comprehensive simulation will use “flight instruments and final versions of the Starliner Flight Program to accurately model the expected behavior of the spacecraft.”
The simulation will last for several days, and will test the program’s functionality from pre-launch to docking, de-docking to landing, according to Boeing.
The extensive exercise to verify the program code was not performed prior to the OFT-1 mission. An independent review team from NASA and Boeing issued 80 recommendations aimed at providing more comprehensive testing of software, process improvements, and some hardware changes.
The investigators also recommended that NASA officials improve their supervision of Boeing’s Starliner team.
The software rehabilitation effort included making sure the Starliner simulators and the simulators were properly configured to mimic how real spacecraft would operate in flight. Then engineers reviewed and updated the spacecraft software code, and completed tests inside the Software Integration Lab.
Boeing said the test included “hundreds of cases, ranging from single driving checks to comprehensive mission scenarios with the core program.”
United Launch Alliance, launch provider Starliner, and NASA are jointly testing the program to ensure proper integration during the spacecraft’s ascent into orbit, docking and separation at the space station.
“As we continue to implement these milestones and reviews, we remain true to our values of safety, quality and integrity,” said Vollmer. “The completion of OFT-2 brings us one step closer to our ultimate goal of transporting astronauts to and from the International Space Station this year.”
Software bugs caught during the OFT-1 mission in December included a timer that an incorrectly set Starliner mission had elapsed before launch. The problem caused the spacecraft’s computer to believe it was in a different flight stage after the Atlas 5 rocket was deployed in orbit, causing the propellant capsule to launch and burning off much of the propellant.
Higher than expected fuel use prevented the Starliner spacecraft from docking with the International Space Station.
Ground teams have uncovered another coding bug that could cause the spacecraft service module to collide with the crew module after the two components were separated just before re-entry. During certain parts of the shortened two-day mission, there were also difficulties establishing a stable communications link between the Starliner spacecraft, NASA’s tracking network and data transmission satellites.
The OFT-2 mission is expected to last about 1-2 weeks.
NASA’s commercial spaceflight manager Phil McCallister said last week that SpaceX’s upcoming Crew Dragon mission – with four astronauts – is scheduled to launch in March or April, around the same time as the Starliner OFT-2 test flight.
The space station has two docking ports to receive the commercial crew capsules, but the next Crew Dragon flight – known as Crew-2 – will arrive at the complex before leaving the current Crew Dragon mission.
This means that the OFT-2 test flight cannot be launched during delivery between Crew-1 and Crew-2 missions.
“We will eliminate the conflict between these missions as we get a little closer, depending on the spacecraft’s preparedness and the needs of the International Space Station,” said McAllister on January 13 at a meeting of the Human Exploration and Operations Committee of the NASA Advisory Council.
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