How it works
If someone is speaking their own opinion, they're generally free to do so so long as it doesn't bring embarrasment to their employer.
If someone is claiming to speak for their employer (especially a government agency like NASA), then the employer has the right to vet what he or she is saying. From what I gather, this scientist appears to be claiming to speak for NASA without NASA's permission. That can be grounds for disciplinary action, even dismissal, in many organizations.