Calling all space geeks (or more accurately, "space tweeps," space geeks who use Twitter): NASA is giving you another chance to experience a Space Shuttle mission firsthand as Twitter correspondents--and registration starts today. This time the event is on February 17at the Johnson Space Center in Houston, where 100 lucky participants will be guests at Mission Control and other facilities during the flight of the Space Shuttle Endeavour (mission STS-130).

Registration starts today (Tuesday, January 26) at noon, Eastern Time, and will be open for one day. The hundred participants will be chosen randomly from among the registrants, with 50 more wait-listed in case the first selections can't make it. I won't be registering, but only because I'll be attending Endeavour's launch at Cape Canaveral on February 6 and participating in another NASA tweetup unrelated to the mission a few days later--I'll let you know more as the time approaches.

The event will provide NASA's Twitter followers with the opportunity to take a tour of NASA's Johnson Space Center, view the Mission Control Center and astronaut training facilities. Tweeps also will be able to speak with flight directors, engineers, astronauts and trainers. The Tweetup will include a "meet and greet" session to allow participants to mingle with fellow Tweeps and the staff behind the tweets on @NASA.

You need to be on Twitter (and supply NASA with your username when you register). And if you're a space geek, why aren't you? For one thing, a few International Space Station (ISS) astronauts are tweeting updates from space; last week Flight Engineer T.J. Creamer (@Astro_TJ) issued http://www.appscout.com/2010/01/astronaut_issues_live_tweet_fr.php, and another crew member, Soichi Noguchi (@Astro_Soichi) tweets in English and in Japanese. @Astro_TJ has solicited questions from his followers, and he responds to at least a few of the tweets he receives.

Houston, we've got a tweetup! Register now--you may be one of the lucky ones. The only catch is that you have to pay your own way.