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Home / Science / Software is a major concern for NASA’s Boeing-built SLS moon rocket

Software is a major concern for NASA’s Boeing-built SLS moon rocket



When it launched, NASA’s Space Launch System missile, a giant 322 feet tall – taller than the Statue of Liberty – would be the most powerful rocket ever to fly, eclipsing even the Saturn V that had sent the spacecraft. Moon astronaut and SpaceX’s Falcon Heavy, which launched commercial and national security satellites as well as founder Elon Musk’s Tesla Roadster on his trip to Mars.

But as NASA approached the SLS’s first flight, sending the Orion spacecraft into orbit around the moon, the officials weren̵

7;t interested in the rocket’s engine but the software that would control everything the rocket did, from setting orbit to opening individual valves to opening and closing.

Computational power has become so important to rockets as the brutal force lifting them out of Earth’s atmosphere, especially rockets like the SLS, is actually a combination of engineered parts. Made by many manufacturers: Boeing builds the “core phase” of the rocket, the main body of the vehicle. Lockheed Martin builds the Orion spacecraft. Aerojet Rocketdyne and Northrop Grumman were responsible for the RS-25 engine and side boosters, respectively. And the United Launch Alliance handled the above phase.

All of these components need to work together for the mission to succeed. But NASA’s Aerospace Safety Advisory Council (ASAP) recently said it was concerned about the discrete way of the complex system being developed and tested.

At an ASAP meeting last month, Paul Hill, a board member and former flight and mission executive at the agency, said “the council has a great deal of concern about capabilities and planning. Terminal integration testing, especially for software flight. “

Instead of a comprehensive avionics test and software to mimic flight, he said, there were “many diverse and distinct laboratories; Emulators and emulators are being used to test subsets of software. “

“As much as possible, the flight systems should be developed for success, with the aim of testing it as if you were flying. Just like how NASA’s operations teams train how you fly and how you fly, ”Hill said.

Also worrying for safety is that NASA and its contractors do not appear to have “taken advantage of the lessons learned” from a flight that crashed last year by Boeing’s Starliner spacecraft, which suffers from some software bugs that prevent it from being able to land internationally. The space station went according to plan and forced the operators to cut the mission short.

NASA has since said that it did a bad job overseeing Boeing in the Starliner program, and has since stated that there will be stricter assessments of their work, especially testing. software.

Concerns about SLS software are the latest red sign for a program that has struggled to overcome a series of excess costs and failures. A series of government oversight reports over the years paint a disturbing picture of poor governance.

Three years ago, the NASA Inspector General reported in an audit that NASA spent more than $ 15 billion on SLS, Orion spacecraft and their related ground systems between 2012 and 2016. According to estimated total amount will amount to 23 billion dollars.

The report criticized Boeing, the main contractor, which it said “always underestimate the scope of work to be performed and therefore the scale and skills of the workforce required”.

NASA says the program is now finally on track, with the car going through a rigorous series of tests called “Green Run” at Stennis’s Space Center in Mississippi culminating in. With a “hot flame” – ignition and last for 8 minutes its engine combustion is expected later this year.

It will then be shipped to the Kennedy Space Center in Florida, before the first launch, currently scheduled for the end of 2021. NASA Administrator Jim Bridenstine said “all the elements we need. for a successful moon landing in 2024 is underway as part of the agency’s Artemis program. And we are moving rapidly to achieve that goal ”- an impressive acceleration ordered by the White House to the initial timetable heralded a moon landing in 2028.

To reach that deadline, however, the flight software has to work perfectly. The first test is expected to take place later next year, when the SLS will fly for the first time on the Artemis I mission, bringing the Orion spacecraft without any crew on board. around the moon

Dan Mitchell, NASA’s senior technical lead in avionics and SLS software engineering, said in an interview: “When all is well understood, flight software is the functional integration of rocket. “Rockets don’t fly without flying software. The software commands all valves and engines. It takes reasons of all the parameters inside the vehicle, navigation and location information and uses all of that information to control the battle. “

Perhaps there is no better illustration of the critical role software plays in space flight and how flaws in coding can have more serious consequences than Starliner’s test flight.

Immediately after reaching orbit, the spacecraft with no astronauts on board, had a problem because the spacecraft’s flight computer turned off for 11 hours. With the spacecraft thinking it was at a completely different point in the mission, it tried to adjust its cruise, burn precious fuel and force its operators to end the mission early without a refund. main goal: docking at the International Space Station. The controllers then discovered another software problem that could cause the service module to collide with the crew compartment after detachment, potentially endangering the astronauts, if any. people on board.

Boeing was able to diagnose the problem, submit a software fix and ultimately bring the spacecraft down safely. Later, Boeing said its software testing was deeply flawed, allowing these two problems to go undetected in a million lines of spacecraft code. It’s an acknowledgment reminiscent of the software problems that happened with the airline’s 737 Max, which suffered two crashes that killed 346 people and remained intact worldwide.

Boeing officials have said that during the test flight, Starliner pulled its time off the rocket. During the test, officials mainly focused on making sure the two vehicles communicated correctly, but cut the test short to never discover that the spacecraft had read the wrong time.

If the test continues, “we got it,” said John Mulholland earlier this year, when he was Boeing’s Starliner program director. He switched to Boeing’s space station program.

During software testing for service module decomposition, Boeing did not use actual hardware but instead was an “emulator,” a computer system designed to mimic the- service module. The problem was that the emulator misprogrammed the thruster configuration at the time of testing, Mulholland said.

NASA officials in charge of the SLS program said they are confident that the testing protocols for the SLS missile and the Orion spacecraft are much more robust. For starters, the program is set up differently. Boeing owns and operates the Starliner spacecraft and uses it to perform a service for NASA – namely, to send their astronauts onto the space station.

In contrast, for the SLS program, NASA owns and will operate the missile, and is responsible for all integration tests.

Mitchell, NASA’s senior engineering lead, said the SLS team was “at the heart” of Starliner’s malfunction. As a result, they spent four days testing the different interfaces between SLS and Orion, he said. “We methodically follow the request. … It’s a very, very detailed and efficient interaction that we have on all the interfaces, ”he said.

The review, he said, raised a problem with how the second stage of the rocket interpreted the data from the first stage, but “has been identified as a benign issue” so there is no need for any fixes. change at this point.

NASA has rejected the safety dashboard results, saying in a statement that “all software, hardware, and combination for every stage of the Artemis I mission are thoroughly tested and evaluated for ensures that it meets NASA’s stringent safety requirements and fully qualifies for human space flight. “

The agency and its contractors are “conducting end-to-end integration testing for the software, hardware, avionics and integrated systems needed to carry out Artemis’ missions.”

Once the vehicle has been shipped to the Kennedy Space Center, testing will continue with a “countdown demonstration and wet dress rehearsal. [by fueling the rocket] with rockets, spacecraft and ground systems before I launched Artemis. ”

Speaking to the press in October, John Shannon, Boeing’s vice president, who oversees the SLS program, said the core phase holds the “brain” of rockets, avionics, and aircraft. and “vehicle control system”.

But he says the company’s software testing and development is limited to what is known as a “stage controller” or “ground software that controls the vehicle itself.”

Shannon said the systems have been “completed, tested in the integrated facilities now [NASA’s] Marshall Space Center. We have had it independently verified and validated to show that it works well with the aircraft software and the kickstand control software. And all are ready. “


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