Patrick,
Not bad for a first draft. A few things:
1. Is there a woodshop or other hobby shop already at the facility purposed for recreational use? If so, it may just be a matter of engaging the shopkeep and proposing new technologies gradually and influencing him/her toward the makerspace concept.
2. Cite precedence. DARPA is heavily interested in makerspaces.
makerspaces.com is their baby, I believe (I have extremely mixed feelings about this, though).
3. Work your way up the chain. Don't start at the top, as a negative reply from the top stops anyone below from saying yes.
4. Engage the reader to meet with you, rather than leaving the ball in their court. "I would like to meet with you to discuss the potential for this community and look forward to your reply." Or something.
5. begone = begun, various other spell check things. Use active voice (John kicked the ball not the ball was kicked by John).
6. Of course, should the hackerspace end up at Stennis, you're definitely not going to get access to the same shops used for rocketry. That would be akin to me asking to use the machine shop where they service my jet. I'd be laughed out of the room. I believe a space already dedicated to recreation is probably your best bet, and then you can gather materials similar to how we did it here in Omaha.
Bottom line: If NASA is anything like where I work, no one wants to take risks that could endanger the mission or their jobs. Make it as easy for them as possible, and start at the bottom. If possible, spin it so that they can use involvement to advance their career. In the military, something like this would be used as a bullet point for an award application since it involves volunteerism (guess what I did!). Maybe you can use that.
Travis