From a MITRE’s news:

The Space Information Sharing and Analysis Center (ISAC) and National Cybersecurity Center announced on Aug. 26 that MITRE will become the Space ISAC’s newest founding member, joining Kratos Defense & Security Solutions and Booz Allen Hamilton. Scott Kordella, MITRE’s executive director for space, will serve on the Space ISAC board of directors.
The Space ISAC aims to “facilitate collaboration across the global space industry to enhance our ability to prepare for and respond to vulnerabilities, incidents, and threats; to disseminate timely and actionable information among member firms; and to serve as the primary communications channel for the sector with respect to this information,” according to an Aug. 26 press release.
MITRE is known in cybersecurity for many publications and tools among them the not-aging Ten Strategies of a World-Class Cybersecurity Operations Center (pdf, I have seen discussed in some space cybersecurity workshops) and the ATT&CK (Adversarial Tactics, Techniques, and Common Knowledge) project.
Space ISAC has a website and a Twitter account.
More on Dark Reading.