OpenAI, maker of ChatGPT and one of the most prominent artificial intelligence companies in the world, said today that it has entered a partnership with Anduril, a defense startup that makes missiles, drones, and software for the United States military. It marks the latest in a series of similar announcements made recently by major tech companies in Silicon Valley, which has warmed to forming closer ties with the defense industry.

“OpenAI builds AI to benefit as many people as possible, and supports US-led efforts to ensure the technology upholds democratic values,” Sam Altman, OpenAI’s CEO, said in a statement Wednesday.

OpenAI’s AI models will be used to improve systems used for air defense, said Brian Schimpf, cofounder and CEO of Anduril, in the statement. “Together, we are committed to developing responsible solutions that enable military and intelligence operators to make faster, more accurate decisions in high-pressure situations,” he said.

OpenAI’s technology will be used to “assess drone threats more quickly and accurately, giving operators the information they need to make better decisions while staying out of harm’s way,” says a former OpenAI employee who left the company earlier this year and spoke on the condition of anonymity to protect their professional relationships.

OpenAI altered its policy on the use of its AI for military applications earlier this year. A source who worked at the company at the time says some staff were unhappy with the change, but there were no open protests. The US military already uses some OpenAI technology, according to reporting by The Intercept.

Anduril is developing an advanced air defense system featuring a swarm of small, autonomous aircraft that work together on missions. These aircraft are controlled through an interface powered by a large language model, which interprets natural language commands and translates them into instructions that both human pilots and the drones can understand and execute. Until now, Anduril has been using open source language models for testing purposes.

Anduril is not currently known to be using advanced AI to control its autonomous systems or to allow them to make their own decisions. Such a move would be more risky, particularly given the unpredictability of today’s models.

A few years ago, many AI researchers in Silicon Valley were firmly opposed to working with the military. In 2018, thousands of Google employees staged protests over the company supplying AI to the US Department of Defense through what was then known within the Pentagon as Project Maven. Google later backed out of the project.

But some US tech companies and workers changed their tune after Russia’s invasion of Ukraine. Now, with AI increasingly viewed in government circles as a transformative and geopolitically significant technology, many tech companies seem more open to military work. Defense contracts also promise to be a lucrative revenue stream for AI firms that need to invest huge amounts of capital into research and development.

One of OpenAI’s more important rivals, the AI startup Anthropic, announced last month that it had entered into a partnership with the defense contractor Palantir to provide “US intelligence and defense agencies” access to its AI models. Around the same time, Meta said it was making its open source Llama AI technology available to US government agencies and contractors working on national security through partnerships with Anduril, Palantir, Booz Allen, Lockheed Martin, and others.

Altman said in the statement that OpenAI would help ensure that the military uses AI with due care. “Our partnership with Anduril will help ensure OpenAI technology protects US military personnel,” he said, “and will help the national security community understand and responsibly use this technology to keep our citizens safe and free.”

Anduril, which was cofounded by Oculus VR creator Palmer Luckey, has risen rapidly within the defense world on the promise of disrupting conventional practices by focusing on advanced technology software. The company has won some major defense contracts, beating out established military contractors.