14 CFR § 1215.110 - User cancellation of all services.
The user has the right to terminate its service contract with NASA at any time. A user who exercises this right after contracting for service shall pay the charge agreed upon for services previously rendered, and the cost incurred by the Government for support of pre-launch activities, services, and mission documentation not included in that charge. The user will remain responsible for the charges for any services actually provided.
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