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Boeing said Monday it requalified the company’s Starliner crew capsule software after programming errors interrupted the spacecraft’s first orbital test flight in 2019, and technicians at the Kennedy Space Center have connected the crew and service modules for the next unmanned Starliner test flight. to the International Space Station in March.
NASA and Boeing officials are officially targeting March 29 for the second Starliner Orbital Flight Test, a repeat of the first test flight in 2019, when software issues prevented the capsule from connecting to the space station. Boeing and NASA officials agreed last year to relaunch the OFT mission to demonstrate an entire Starliner flight sequence before allowing the craft to fly astronauts.
The Starliner landed safely in New Mexico, but engineers launched a review of all of the spacecraft’s software code to prevent the issues from reoccurring on the first OFT mission.
Several NASA and industry officials have said the launch of the OFT-2 mission may be brought forward to around March 25. Boeing’s Starliner missions take off on United Launch Alliance Atlas 5 rockets from the Cape Canaveral space station, and the capsule lands under parachutes at one of the many sites in the western United States.
The OFT-2 mission will lay the groundwork for Starliner’s next test flight to transport three NASA astronauts to the space station later this year, followed by the start of regular crew rotation flights.
Boeing said on Monday that engineers had performed a “full review” of the Starliner’s flight software. The teams also evaluated the process for qualifying future software changes and upgrades, the company said.
“The work this team has put into the comprehensive development of our software is a defining moment for the program,” said John Vollmer, vice president and program director for Starliner, in a statement. “We’re smarter as a team after going through this process, and most importantly, we’re smarter as a manned flight community.”
Meanwhile, a Boeing spokesperson said technicians from NASA’s Kennedy Space Center commercial team and cargo handling facility docked the crew and service modules last week to the OFT-2 mission, an important step in preparing the spacecraft for launch.
Assuming the OFT-2 mission stays with a launch date of around March 25, Boeing crews will load the Starliner with a hypergolic maneuvering thruster next month before transporting the capsule to the Atlas 5 launch pad. .
A hardware change for the OFT-2 mission is the installation of a new docking system cover on the nose of the Starliner crew module. The door is designed to better protect sensitive docking port components during the heat of re-entry and will help ensure that Starliner Crew Modules can be reused at least 10 times, depending on the spacecraft’s design specifications, have officials said.
The door will open once the Starliner reaches orbit, revealing the craft’s docking interface to connect to the space station. After undocking, the door will close to reenter. The cover is similar to the nose cone door of SpaceX’s Crew Dragon spacecraft.
Boeing plans to rotate between two reusable crew modules for all planned Starliner missions. Each flight will use a new service module, which provides propulsion and power generation capability for the spacecraft. The OFT-1 mission crew module is being refurbished for the Boeing Crew Test Flight, the first Starliner mission with astronauts.
NASA awarded contracts to Boeing and SpaceX in 2014 to develop the Starliner and Crew Dragon spacecraft to transport astronauts to and from the space station. Both programs experienced technical delays, but SpaceX successfully launched its first two crew missions – a test flight and its first operational crew rotation mission – last year, restoring spaceflight capability. inhabited orbital in the United States for the first time since the end of space. shuttle program in 2011.
The start of operational flights with the Boeing Starliner will give the United States two models of independent spacecraft capable of carrying crews into low earth orbit for the first time in the history of the space program.
Boeing said the software requalification milestone paves the way for an end-to-end simulation of the OFT-2 test flight at the company’s avionics and software integration lab in Houston. The end-to-end simulation will use “flight hardware and final versions of Starliner’s flight software to accurately model the expected behavior of the spacecraft,” Boeing said.
The simulation will run for several days, testing the functionality of the software from pre-launch to docking and undocking to landing, according to Boeing.
End-to-end repetition was not performed to verify software code prior to OFT-1 mission. An independent NASA-Boeing review team made 80 recommendations to provide more in-depth software testing, process improvements, and some hardware changes.
Investigators also recommended that NASA officials improve their oversight of Boeing’s Starliner team.
The software requalification effort involved making sure that the Starliner simulators and emulators were properly configured to mimic the operation of the actual spacecraft in flight. Engineers then reviewed and updated the spacecraft’s software code and performed tests in the software integration lab.
Boeing said the tests included “hundreds of cases ranging from single order checks to full end-to-end mission scenarios with the base software.”
United Launch Alliance, the Starliner launch provider, and NASA are involved in software testing to ensure proper integration during the ascent of the spacecraft into orbit, and the docking and undocking of the space station.
“As we continue to achieve these critical milestones and reviews, we remain true to our values of safety, quality and integrity,” said Vollmer. “The completion of OFT-2 brings us closer to our ultimate goal of transporting astronauts to and from the International Space Station this year.”
Software errors discovered during the OFT-1 mission in December included a Starliner mission timer that was incorrectly set prior to launch. The problem led the spacecraft’s computer to believe it was in a different phase of flight after the Atlas 5 rocket was deployed into orbit, causing the thrusters to encapsulate and burning too much thruster.
The higher than expected fuel consumption prevented the Starliner spacecraft from docking with the International Space Station.
Ground crews discovered another software coding error that could have caused the spacecraft’s service module to collide with the crew module after the two elements separated just before reentry. During parts of the shortened two-day mission, difficulties were also encountered in establishing a stable communication link between the Starliner spacecraft and NASA’s network of tracking and data relay satellites.
The OFT-2 mission is expected to last approximately one to two weeks.
Phil McAlister, director of commercial spaceflight at NASA, said last week that SpaceX’s next Crew Dragon mission – with four astronauts – is expected to launch in March or April, around the same time as the test flight. Starliner OFT-2.
The space station has two docking ports to receive commercial crew pods, but the next Crew Dragon flight – known as Crew-2 – will arrive at the resort before the current Crew Dragon mission departs.
This means that the OFT-2 test flight cannot be launched while transferring between Crew-1 and Crew-2 missions.
“We will come out of these missions as we get a little closer, depending on the readiness of the spacecraft and the needs of the ISS,” McAlister said Jan. 13 in a meeting of the Exploration and Human Exploitation Committee of the NASA Advisory Council.
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Follow Stephen Clark on Twitter: @ StephenClark1.
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