This channel is only available off of a mpeg4 feed now, right? If so, the only way to get it is to have Hd capable equipment. If so, I say dump the sd feed and only carry the Hi Definition feed. Maybe when d14 hits. There are many channels that I believe that are like this, and the shopping channels, that I kind of expect to launch with d14 when bandwidth will be far less of a limited resource.
By moving it to HD only from SD you're talking about 5X the bandwidth for that channel vs today's usage for SD for that channel. Then the next question becomes, would you rather have Nasa in HD or something else in HD? There are always tradeoffs. Someone should go back here on DBS Talk and see how NASA ranked vs the others. I'll bet it was way down the list.
Also keep in mind that Nasa is a public interest channel and they are treated in a different manner than regular channels. Nasa is at an orbital slot right now because as a public interest channel, DTV is required to put a certain percentage (4%) per channel allocation to public interests. That is why they moved NASA and Baby First over to the MPEG4 slot at 103 or 99 degrees to begin with.
I think there is a reason why almost no one carries NASA in HD. It's definitely a cool channel and right now some very cool things going on with Mars and the rover, but the average citizen would rate it fairly low on their list, otherwise you would have every major carrier with that channel. Bandwidth is precious for everyone - telco, cable, satellite - decisions have to be made how to utilize that bandwidth. On this channels, seems nearly unanimous how everyone is delivering it - in SD for the time being for everyone sans one small cable company in one market that happens to be the backyard of NASA.