Satellite Cybersecurity Act This bill addresses cybersecurity matters related to commercial satellite systems. Specifically, the Cybersecurity and Infrastructure Security Agency (CISA) must maintain a publicly available clearinghouse of resources concerning the cybersecurity of commercial satellite systems. CISA must also develop voluntary recommendations for the development, maintenance, and operation of such systems. The recommendations must include measures to protect systems against cyber-related vulnerabilities, risks, and attacks. The bill also requires the Government Accountability Office (GAO) to study and report on federal actions to support the cybersecurity of commercial satellite systems, including with respect to critical infrastructure sectors. In carrying out its study and report, the GAO must coordinate with designated federal agencies.