So they either need their current DNS servers to be able to internally resolve the A records of the CDN. But it needs a setup that can replicate the geo-replication that otherwise Alamai handles. Possible but not easy.
Or needs a webserver that just performs a redirect. And put its IP in the DNS. technically easy, but its another server to maintain. And at nasa 'level', it wont be a single server. It will multiple servers - probably geographically distributed.
(or they can pay for a service that handles this - which means needs budget)