NASA plans to fly its X-57 electric plane this year

NASA plans to fly its X-57 electric plane this year

Some time later this year—maybe this summer, maybe this fall—NASA’s electric aircraft, the X-57, is set to take off in California. It’s what NASA describes as its “first all-electric experimental aircraft,” and when it takes off from the ground, it won’t look like what NASA depicted the plane on its website.

Instead of 14 electric motors and propellers, the aircraft will have just two. But those two motors, powered by more than 5,000 cylindrical battery cells in the aircraft’s fuselage, should be enough to get it up in the air before 2023 is over, which is when the program is set X-57 with power down too.

Here’s what you know about how the plane will work, the challenges the program faced, and how lessons from spaceflight helped inform the details of its battery system.

Modification 2

If the plane does indeed take flight this year as planned, it will do so in what is known as Modification 2, in which a single electric motor and a propeller on each wing will give the aircraft the thrust it needs to take off. the skies.

Although the aeronautical and space agency had hoped to fly the plane – which is based on the Tecnam P2006T – in additional configurations, known as Modifications 3 and 4, that will not happen. Why? Because it’s difficult to fly planes safely on electricity alone, and the program is only funded through 2023. (IEEE Spectrum has more on the program’s original plans.)

“We’ve been learning a lot over the years, and we thought we’d learn through flight tests – it turns out we had a lot of lessons to learn during the design and integration quality and airworthiness phases, so we ended up spending more more time and resources on that,” says Sean Clark, principal investigator of the X-57 program at NASA.

“And that was invaluable,” he says. “But it means we won’t have resources for that Mod 4 in the end [or 3] flights.”

It will still fly as an all-electric plane, but in Mod 2, with two motors.

Exploding transistors

One glitch the team had to resolve before the aircraft could fly safely involved components that electricity from the batteries must travel through before reaching the motors. The problem was with transistor modules inside the inverters, which convert electricity from DC to AC.

“We were using these modules that were several transistors in a package – we expected to be able to tolerate the types of environments that we expected them to withstand,” says Clark. “But every time we tested them, they would fail. We’d just have transistors blowing up in our environmental test room.”

[Related: This ‘airliner of the future’ has a radical new wing design]

A component failure—like a piece of equipment blowing up—is the kind of issue aircraft manufacturers prefer to solve on the ground. Clark says they figured it out. “We took them apart a lot—after they explode, it’s hard to know what went wrong,” he notes, lightly, in a way that suggests an engineer with a lingering problem. The solution was newer hardware and “essentially redesigning the inverter system from the ground up,” he notes.

They are “working very well now,” he says. “We’ve put a whole team through qualification, and they’ve all stepped up.”

NASA aims to fly its experimental electric plane this year
An older rendering of the X-57 shows it with a thin wing and 14 motors; it will not fly with this configuration. NASA Graphic / NASA Langley / Advanced Concepts Lab, AMA, Inc.

Lessons from space

Conventional aircraft burn fossil fuels, a naturally flammable and explosive substance, to power their engines. Those working on electric, battery-powered aircraft must also ensure that the battery cells do not spark fires. Last year in Kansas, for example, an FAA-sponsored test showed a pack of aviation batteries being dropped 50 feet to make sure they could handle the impact. They did.

In the X-57, the batteries are a model called 18650 cells, made by Samsung. The aircraft uses 5,120 of them, divided into 16 modules of 320 cells each. A single module, which includes both battery cells and packaging, weighs about 51 pounds, Clark says. The trick is to make sure that all these components are packaged in the right way to avoid a fire, even if one battery fails. In other words, failure was an option, but they plan to manage any failure so it doesn’t start a blaze. “​​​​​​​We found that there was no industry standard for how to package these cells into a high-voltage, high-power package, which would also protect them against cell failures,” says Clark.

[Related: The Air Force wants to modernize air refueling, but it’s been a bumpy ride]

Help came from higher up. “We managed to redesign the battery pack based on a lot of input from some of the design team working on the space station here at NASA,” he says. He notes that lithium batteries on the International Space Station, as well as astronauts’ use of EVA suits and a device called the pistol grip tool, were relevant examples in the process. The main takeaways related to the spacing between the battery cells, as well as how to handle the heat if a cell malfunctioned, for example, a thermal runout. “What Johnson [Space Center] One of the most effective strategies was to let that heat from that cell go into the aluminum structure, but also let the other cells around it absorb a little bit of heat each,” he explains.

NASA isn’t the only one exploring the frontier of electric aviation, which shows one way the aviation industry could be greener for short flights. Others working in the space include Beta Technologies, Joby Aviation, Archer Aviation, Wisk Aero, and Eviation with a plane called Alice. One notable company, Kitty Hawk, closed last year.

Sometime this year, the X-57 should fly for the first time, and will likely make multiple sorties. “I’m still excited about this technology,” says Clark. “I look forward to my children being able to make short flights on electric planes in 10, 15 years – it will be a great step for aviation.”

Watch a short video about the aircraft, below:

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