U.S. space technology and satellite giant Maxar has confirmed a data breach involving the personal information of its employees, according to a filing with state regulators.

The Colorado-headquartered Maxar operates imaging satellites and manufactures spacecraft, and claims to operate one of the largest commercial satellite constellations on orbit. Maxar has long been a significant provider of commercial satellite imagery to the U.S. government, which uses the imagery for mission-critical planning, intelligence gathering, and disaster response. 

In a required data breach notice filed with California’s attorney general last week, Maxar said a hacker using a Hong Kong-based IP address compromised its network on October 4 to access files containing employee’s personal data. It’s not yet known if the alleged hacker is located in Hong Kong, or used a server in Hong Kong to hide their real location.

Maxar said it discovered the breach a week later on October 11 and took “immediate action” to prevent further unauthorized access to the system. “Nevertheless, according to our investigation, the hacker likely had access to the files on the system for approximately one week before this action was taken,” Maxar said in the disclosure. 

The information contained within the compromised files includes employees’ names, gender, physical addresses, Social Security numbers, business contact information, employment status, employee number, and job information, according to Maxar.

According to the company’s website, Maxar has 2,600 employees — more than half of which attained U.S. security clearances. These are required to perform classified work for the U.S. government, such as national security missions.

Maxar, which last year completed its $6.4 billion sale to private equity giant Advent International, hasn’t said how many of its employees were impacted by the breach.

Maxar spokesperson Kristin Carringer didn’t immediately respond to TechCrunch’s questions.