The AIAA regularly organizes fora, as well as full-scale conferences, on space topics, although I don’t recall if they have held a forum like this specifically on commercial space and exploration in the recent past.

You should also note that the two senators who have been invited are already strongly pro-space: Brownback and Nelson are often the only two members of the Senate Commerce Committee’s science, technology, and space subcommittee to attend hearings on space topics. Brownback in particular strongly (zealously?) pursues a greater role for the private sector in space; Nelson, I think, tends to be a little more cautious.

I like that they invited both Republican and Democrate Senators. The important thing will be support for good ideas that might come from a meeting like this. The Space Exploration Alliance should follow up with the Senators to keep it in their mind and put forth legislation in support of private companies.