GRAIL launch Tweetup participants pose for a group photograph Wednesday, September 7, 2011, at the NASA Kennedy Space Center in Cape Canaveral, Fla. Photo Credit: (NASA/Bill Ingalls)

Guests at NASA Headquarters in Washington, DC prepare for a Tweetup on July 21, 2009. Nearly 200 of NASA’s Twitter followers are in attendance, which features a presentation and a question and answer session with the crew of the STS-125 shuttle mission to repair the Hubble Space Telescope. Photo Credit: (Carla Cioffi)

Guests at NASA Headquarters in Washington, DC prepare for a Tweetup on July 21, 2009. Nearly 200 of NASA’s Twitter followers are in attendance, which features a presentation and a question and answer session with the crew of the STS-125 shuttle mission to repair the Hubble Space Telescope. Photo Credit: (Carla Cioffi)

John Yembrick, NASA Public Affairs Officer, introduces a live Tweetup event to thirty-five of NASA's Twitter followers at NASA Headquarters in Washington, Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi)

Former NASA astronaut Tom Jones answers questions from Tweetup attendees at NASA Headquarters in Washington on what it is like to live and work in space, Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi) 

Jon Cowart @Rocky_Sci, orbiter engineering manager, Space Shuttle Program, interacts with Tweetup participant, Jen Vargas, @jenvargus, as he speaks to participants at the two-day STS-132 Launch Tweetup at Kennedy Space Center, Thursday, May 13, 2010, in Cape Canaveral, Fla. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Paul E. Alers)

Attendees at a two-day NASA Tweetup at Kennedy Space Center twitter live about their impressions during the Tweetup in Cape Canaveral, Fla., Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi) 

Romeo Durscher from Stanford, CA, who goes by @RomeoCH on Twitter, tweets with his Solar Dynamics Observatory (SDO) mascot named "Camilla" by his side during the NASA STS-133 mission tweetup on Monday, Nov., 1, 2010 at the NASA Kennedy Space Center in Cape Canaveral, Fla. NASA Tweetups provide @NASA followers with the opportunity to go behind-the-scenes at NASA facilities and events and speak with scientists, engineers, astronauts and managers. Photo Credit: (NASA/Bill Ingalls)

Attendees at a two-day NASA Tweetup at Kennedy Space Center twitter live about their impressions during the Tweetup in Cape Canaveral, Fla., Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Guests use their laptop computers to "Tweet" and follow a NASA STS-127 crew presentation on Twitter at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (NASA/Carla Cioffi)

Guests use their laptop computers to "Tweet" and follow a NASA STS-125 crew presentation on Twitter at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

Al Feinberg from NASA Television, interviews a guest at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance, which features a presentation and a question and answer session with the crew of the STS-125 shuttle mission to repair the Hubble Space Telescope. Photo Credit: (Carla Cioffi)

Al Feinberg from NASA Television, center, interviews a guest at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance, which features a presentation and a question and answer session with the crew of the STS-127 shuttle mission to install new hardware and expand the Japanese Kibo laboratory on the International Space Station. Photo Credit: (NASA/Carla Cioffi)

NASA astronaut Mike Fincke, a former International Space Station commander, is seen on screen as he answers questions from NASA Twitter followers during a live Tweetup event held at NASA Headquarters in Washington, Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi)

NASA astronaut Mike Fincke, a former International Space Station commander, seen on screen, is asked a question by a NASA Twitter follower, left, during a question and answer session at a live Tweetup event at NASA Headquarters in Washington, Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi)

NASA astronaut TJ Creamer talks about his experience in space during a "Tweetup" at NASA Headquarters, Thursday, July 29, 2010, in Washington. Creamer, who spent 161 days living aboard the International Space Station as part of the Expedition 22/23 crew, set up the orbiting outpost's live Internet connection and posted updates about the mission to his Twitter account, sending the first live tweet from orbit. Photo Credit: (NASA/Paul E. Alers)

NASA astronaut TJ Creamer talks about his experience in space during a "Tweetup" at NASA Headquarters, Thursday, July 29, 2010, in Washington. Creamer, who spent 161 days living aboard the International Space Station as part of the Expedition 22/23 crew, set up the orbiting outpost's live Internet connection and posted updates about the mission to his Twitter account, sending the first live tweet from orbit. Photo Credit: (NASA/Paul E. Alers)

NASA astronaut TJ Creamer talks about his experience in space during a "Tweetup" at NASA Headquarters, Thursday, July 29, 2010, in Washington. Creamer, who spent 161 days living aboard the International Space Station as part of the Expedition 22/23 crew, set up the orbiting outpost's live Internet connection and posted updates about the mission to his Twitter account, sending the first live tweet from orbit. Photo Credit: (NASA/Paul E. Alers)

NASA astronaut TJ Creamer talks about his experience in space during a "Tweetup" at NASA Headquarters, Thursday, July 29, 2010, in Washington as Twitter followers looks on. Creamer, who spent 161 days living aboard the International Space Station as part of the Expedition 22/23 crew, set up the orbiting outpost's live Internet connection and posted updates about the mission to his Twitter account, sending the first live tweet from orbit. Photo Credit: (NASA/Paul E. Alers)

NASA astronaut TJ Creamer talks about his experience in space during a "Tweetup" at NASA Headquarters, Thursday, July 29, 2010, in Washington. Creamer, who spent 161 days living aboard the International Space Station as part of the Expedition 22/23 crew, set up the orbiting outpost's live Internet connection and posted updates about the mission to his Twitter account, sending the first live tweet from orbit. Photo Credit: (NASA/Paul E. Alers)

NASA Twitter follower Sarah Smith, Twitter handle @smith5se, asks a question at a Tweetup hosted by astronaut Ron Garan at NASA Headquarters in Washington, Tuesday, Feb. 14, 2012. Photo Credit: (NASA/Carla Cioffi)

Canadian Space Agency Astronaut and STS-127 Mission Specialist Julie Payette answers questions at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (NASA/Carla Cioffi)

NASA Astronaut and STS-127 Mission Commander Mark Polansky, left, answers questions at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (NASA/Carla Cioffi)

Barbie Dolls stand by during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

Actor and Producer Levar Burton tweets with two devices during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

NASA Astronaut Clay Anderson speaks to NASA Twitter followers during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

NASA Twitter followers attending a two-day NASA Tweetup presented NASA Public Affairs Officers with a signed poster from Kennedy Space Center expressing their appreciation for hosting this unique event, Monday, Nov. 16, 2009 in Cape Canaveral, Fla. Photo Credit: (NASA/Carla Cioffi)

NASA Astronaut and STS-125 Mission Specialist Michael Good answers a question during a presentation with fellow STS-125 shuttle mission crew members at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

NASA Astronaut and STS-125 Mission Specialist John Grunsfeld answers a question during a presentation with fellow STS-125 shuttle mission crew members at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

Actor Seth Green, a NASA Twitter follower, tweets from his device during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

NASA Astronaut Mike Massimino, known as "Astro_Mike" on Twitter, prepares to give a presentation with fellow STS-125 shuttle mission crew members at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

NASA AStronaut and STS-125 Mission Specialist Andrew Feustel, right, answers a question during a presentation with fellow STS-125 shuttle mission crew members at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

Heather Good, Twitter handle @foundonmars, tweets during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

NASA Astronaut and STS-125 Mission Pilot Scott Altman prepares to give a presentation with fellow STS-125 shuttle mission crew members at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

NASA Astronaut and STS-127 Mission Commander Mark Polansky, also known as @Astro_127 on Twitter, answers questions at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (NASA/Carla Cioffi)

NASA Astronaut Mike Massimino, known as "Astro_Mike" on Twitter, answers a question during a presentation with fellow STS-125 shuttle mission crew members at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

NASA Astronaut and Mission Speciliast Tom Marshburn answers questions at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (NASA/Carla Cioffi)

NASA Twitter followers are seen through a space suit helmet during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

NASA Astronaut and STS-125 Mission Pilot Scott Altman answers questions at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

NASA Ames Tweetup and tour of center with John Yembrick, Ames PAO Chief (acting) and host of the event.

Former NASA astronaut Tom Jones shows off a sleeping bag used by astronauts living aboard the International Space Station during a NASA Tweetup event at NASA Headquarters in Washington, Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi)

NASA Deputy Administrator Lori Garver welcomes attendees to a live Tweetup event at NASA Headquarters in Washington with astronauts living aboard the International Space Station (ISS), Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi)

NASA Astronaut and STS-127 Mission Commander Mark Polansky, far left, answers questions at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (NASA/Carla Cioffi)

NASA Astronaut and Mission Specialist Dave Wolf, center, answers questions at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (NASA/Carla Cioffi)

NASA Twitter followers are seen at a Tweetup hosted by NASA astronaut Ron Garan at NASA Headquarters in Washington, Tuesday, Feb. 14, 2012. Garan was a flight engineer on both the Expedition 27 and 28 missions at the International Space Station. Photo Credit: (NASA/Carla Cioffi)

Heather Paul, a project engineer for Johnson Space Center, talks about space suit technology during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

NASA Twitter followers are seen at a Tweetup hosted by NASA astronaut Ron Garan at NASA Headquarters in Washington, Tuesday, Feb. 14, 2012. Garan was a flight engineer on both the Expedition 27 and 28 missions at the International Space Station. Photo Credit: (NASA/Carla Cioffi)

A NASA Twitter follower tweets during astronaut Ron Garan's Tweetup at NASA Headquarters in Washington, Tuesday, Feb. 14, 2012. Garan was a flight engineer on both the Expedition 27 and 28 missions at the International Space Station. Photo Credit: (NASA/Carla Cioffi)

STS-127 shuttle mission crew members from left, Commander Mark Polansky, Pilot Doug Hurley, Mission Specialists Christopher Cassidy, Tom Marshburn, Dave Wolf and Julie Payette of the Canadian Space Agency, give a presentation at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. The NASA Tweetup featured a presentation and a question and answer session with the crew of the STS-127 shuttle mission to install new hardware and expand the Japanese Kibo laboratory on the International Space Station. Photo Credit: (NASA/Carla Cioffi)

NASA Ames Tweetup and tour of center by invitation of the NASA Ames Public Affairs Office. Tweeter guest during the morning overview sessions at the visitor's center.

NASA Ames Tweetup and tour of center by invitation of the NASA Ames Public Affairs Office. Tweeter group in front of Ames Administration building N-200 .

NASA astronaut Mike Massimino, left, and Sesame Street's Elmo speak at the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. Elmo asked the astronauts questions about living and working in space. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

Twitter users Risa Wechster from Stanford University, left, and Daniel Holz from Los Alamos, both twitter for @cosmicvariance during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Twitter user Karim Jazouani from Casablanca, Morocco, who goes by the twitter name @karimjazouani, uses his laptop during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Mike Massimino, NASA Astronaut, known on twitter as @Astro_Mike, speaks during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Wayne Hale, NASA strategic program planning manager, is seen on video camera as he speaks during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi) 

Twitter users arrive for the start of a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

NASA Twitter followers wave to the Astro van as it passes by en route to launch pad 39A with the crew of STS-129, Monday, Nov. 16, 2009 at Kennedy Space Center in Cape Canaveral, Fla. The Twitter users were part of a unique two-day NASA Tweetup at Kennedy Space Center. Photo Credit: (NASA/Carla Cioffi)

Richard Hay, @WinObs, looks at an astronaut boot, during the two-day STS-132 Launch Tweetup at Kennedy Space Center, Thursday, May 13, 2010, in Cape Canaveral, Fla. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Paul E. Alers)

Miles O'Brien, veteran space reporter, known on twitter as @milesobrien, speaks during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Actor Seth Green, a NASA Twitter follower, holds up his mobile device bearing the NASA emblem during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

Twitter user Paul Thompson from Dallas, Texas, who goes by the twitter name @flyingphotog, uses his laptop during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Veronica McGregor, NASA public affairs officer, known on twitter as @veronicamcg, speaks during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

NASA Twitter followers attending the STS-135 Tweetup are seen through the helmet of a NASA space suit, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

Cassie Barnes, Twitter handle @celticfeminist, tweets during the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

NASA Astronaut Janet Voss speaks to participants at the two-day STS-132 Launch Tweetup at Kennedy Space Center, Thursday, May 13, 2010, in Cape Canaveral, Fla. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Paul E. Alers)

Susie Bodman, Twitter handle @sciwhat, tweets during the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

Kendal Van Dyke, a database professional that is followed on Twitter @twitter.com/sqldba, takes part in the two-day STS-132 Launch Tweetup at Kennedy Space Center, Thursday, May 13, 2010, in Cape Canaveral, Fla. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Paul E. Alers)

Ares I-X Deputy Mission Manager Jon Cowart shows a space shuttle solid rocket booster (SRB) separation bolt during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Tracy Thumm, left, and Justin Kugler both from the International Space Station Program Science Office at Johnson Space Center speak at the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

NASA Tweetup participants stand at the launch clock, Friday, July 8, 2011, prior to the launch of the space shuttle Atlantis (STS-135) at Kennedy Space Center in Cape Canaveral, Fla. Space shuttle Atlantis is set to launch on the final flight of the shuttle program on a 12-day mission to the International Space Station. The STS-135 crew will carry the Raffaello multipurpose logistics module containing supplies and spare parts for the space station. Photo Credit: (NASA/Paul E. Alers)

Ann Marie Cunningham, center, along with other NASA Twitter followers wave to the Astro van as it passes by en route to launch pad 39A with the crew of STS-129, Monday, Nov. 16, 2009 at Kennedy Space Center in Cape Canaveral, Fla. The Twitter users were part of a unique two-day NASA Tweetup at Kennedy Space Center. Photo Credit: (NASA/Carla Cioffi)

Twitter users arrive for the start of a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Twitter users arrive for the start of a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Ron Woods, an equipment specialist, who has been a space suit designer from Mercury to now speaks to participants at the two-day STS-132 Launch Tweetup at Kennedy Space Center, Thursday, May 13, 2010, in Cape Canaveral, Fla. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Paul E. Alers)

Lar DeSouza, Twitter handle @lartist, a cartoonist, sketches during the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

Twitter user Karim Jazouani from Casablanca, Morocco, who goes by the twitter name @karimjazouani, uses his laptop during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Twitter user Dave Gibson from Lawrenceville, GA, who goes by the twitter name @davecgibson, listens to a guest speaker during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

sends streaming live video via a mobile phone attached to his hat to his website of Phylise Banner, who goes by @Phylisebanner on Twitter, as she stands in an astronaut suit on display during the tweetup on Monday, Nov., 1, 2010 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Photo Credit: (NASA/Bill Ingalls)

Wayne Hale, NASA strategic program planning manager speaks during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the STS-129 space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)

Stephanie Stilson, space shuttle discovery processing director, speaks to participants at the two-day STS-132 Launch Tweetup at Kennedy Space Center, Thursday, May 13, 2010, in Cape Canaveral, Fla. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Paul E. Alers)

NASA Ames Tweetup and tour of center by invitation of the NASA Ames Public Affairs Office. Tweeter group visit the Kepler Science Ops Center (SOC), while there recieve a overview and participate in a Q & A from Jeff Van Cleve.

NASA astronaut Mike Massimino, far left, Sesame Street's Elmo and NASA astronaut Doug Wheelock, far right, speak at the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. Elmo asked the astronauts questions about living and working in space. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

NASA Twitter followers tour the International Space Station Center at the Kennedy Space Center in Cape Canaveral, Fla. as part of a two-day Tweetup event, Sunday, Nov. 15, 2009. Tweeps had the chance to enter full-scale mock-ups of the Habitation Module and see how Space Station crew members live, sleep and work. Photo Credit: (NASA/Carla Cioffi) 

STS-135 Tweetup participants are seen outside launch pad 39a and space shuttle Atlantis following the Rotating Service Structure rollback, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla.About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

Astronaut Ron Garan, far right, discusses his experiences while living on the International Space Station as part of the Expedition 27 and 28 mission during a tweetup at NASA Headquarters in Washington, Tuesday, Feb. 14, 2012. Garan has logged more than 178 days in space and 27 hours and 3 minutes of EVA in four spacewalks. Photo Credit: (NASA/Carla Cioffi)

Actor Seth Green, right, takes a quick photo of two NASA Tweeps holding a Golden Orb Spider during the STS-134 Tweetup, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Photo Credit: (NASA/Paul E. Alers)

Astronaut Ron Garan discusses his experiences while living on the International Space Station as part of the Expedition 27 and 28 mission during a tweetup at NASA Headquarters in Washington, Tuesday, Feb. 14, 2012. Garan has logged more than 178 days in space and 27 hours and 3 minutes of EVA in four spacewalks. Photo Credit: (NASA/Carla Cioffi)

Robert D. Braun, NASA Chief Technologist at NASA Headquarters, speaks to participants at the two-day STS-132 Launch Tweetup at Kennedy Space Center, Thursday, May 13, 2010, in Cape Canaveral, Fla. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Paul E. Alers)

Astronaut Ron Garan discusses his experiences while living on the International Space Station as part of the Expedition 27 and 28 mission during a tweetup at NASA Headquarters in Washington, Tuesday, Feb. 14, 2012. Garan has logged more than 178 days in space and 27 hours and 3 minutes of EVA in four spacewalks. Photo Credit: (NASA/Carla Cioffi)

NASA Twitter followers, who particiapted in the STS-134 Tweetup are seen together by the launch clock, Friday, April 29, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. Later the group will watch the launch of Endeavour as it heads to the International Space Station on a 14-day mission to deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Liftoff is targeted for 3:47 pm. Photo Credit: (NASA/Paul E. Alers)

Astronaut Doug Wheelock discusses his experiences while living on the International Space Station during a tweetup at NASA Headquarters in Washington, Wednesday, March 16, 2011. Wheelock, who has accumulated a total of 178 days in space, assumed command of the International Space Station and the Expedition 25 crew. During Expedition 25, there were more than 120 microgravity experiments in human research; biology and biotechnology; physical and materials sciences; technology development; and Earth and space sciences. Wheelock also responded to an emergency shutdown of half of the station's external cooling system and supported three unplanned spacewalks to replace the faulty pump module that caused the shutdown. His efforts restored the station's critical cooling system to full function. The mission duration was 163 days. Photo Credit: (NASA/Paul E. Alers)

Astronaut Doug Wheelock discusses his experiences while living on the International Space Station during a tweetup at NASA Headquarters in Washington, Wednesday, March 16, 2011. Wheelock, who has accumulated a total of 178 days in space, assumed command of the International Space Station and the Expedition 25 crew. During Expedition 25, there were more than 120 microgravity experiments in human research; biology and biotechnology; physical and materials sciences; technology development; and Earth and space sciences. Wheelock also responded to an emergency shutdown of half of the station's external cooling system and supported three unplanned spacewalks to replace the faulty pump module that caused the shutdown. His efforts restored the station's critical cooling system to full function. The mission duration was 163 days. Photo Credit: (NASA/Paul E. Alers)

Astronaut Doug Wheelock discusses his experiences while living on the International Space Station during a tweetup at NASA Headquarters in Washington, Wednesday, March 16, 2011. Wheelock, who has accumulated a total of 178 days in space, assumed command of the International Space Station and the Expedition 25 crew. During Expedition 25, there were more than 120 microgravity experiments in human research; biology and biotechnology; physical and materials sciences; technology development; and Earth and space sciences. Wheelock also responded to an emergency shutdown of half of the station's external cooling system and supported three unplanned spacewalks to replace the faulty pump module that caused the shutdown. His efforts restored the station's critical cooling system to full function. The mission duration was 163 days. Photo Credit: (NASA/Paul E. Alers)

A tweetuup participant videotapes with her iPhone and tweets as astronaut Doug Wheelock discusses his experiences while living on the International Space Station during a tweetup at NASA Headquarters in Washington, Wednesday, March 16, 2011. Wheelock, who has accumulated a total of 178 days in space, assumed command of the International Space Station and the Expedition 25 crew. During Expedition 25, there were more than 120 microgravity experiments in human research; biology and biotechnology; physical and materials sciences; technology development; and Earth and space sciences. Wheelock also responded to an emergency shutdown of half of the station's external cooling system and supported three unplanned spacewalks to replace the faulty pump module that caused the shutdown. His efforts restored the station's critical cooling system to full function. The mission duration was 163 days. Photo Credit: (NASA/Paul E. Alers)

NASA Ames Tweetup and tour of center by invitation of the NASA Ames Public Affairs Office. Tweeter guests during the morning session at the visitor's center with Natalie Batalha, Kepler Scientist from San Jose State University giving overview of mission to locate distant earth like planets with the Kepler Space Telescope.

CAPE CANAVERAL, Fla. -- At Kennedy Space Center in Florida, NASA is hosting a two-day Tweetup for 150 of its Twitter followers of space shuttle Endeavour's STS-134 mission. A Tweetup is an informal meeting of people who use the social messaging medium Twitter. This Tweetup is an opportunity to learn more about NASA, explore Kennedy Space Center and experience a space shuttle launch. Actor_Director LeVar Burton, participating in the Tweetup is interviewed by Kennedy's News Chief Allard Beutel. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Launch is scheduled for April 29 at 3:47 p.m. EDT. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov_mission_pages_shuttle_shuttlemissions_sts134_index.html. Photo credit: NASA_Jack Pfaller

Expedition 20 Flight Engineers Jeff Williams, left, and Nicole Stott, seen on screen, are asked a question by a NASA Twitter follower, right, during a question and answer session at a live Tweetup event at NASA Headquarters in Washington, Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi)

Expedition 20 Flight Engineers Jeff Williams, left, and Nicole Stott, seen on screen, are asked a question by a NASA Twitter follower, center, during a question and answer session at a live Tweetup event at NASA Headquarters in Washington, Wednesday, Oct. 21, 2009. Photo Credit: (NASA/Carla Cioffi)

Twitter user Ann Marie Cunningham who goes by the twitter name @talkingscience.org, right, uses her laptop, while Laura Burns, who goes by the twitter name @moonrangerlaura, listens to a guest speaker during a two-day NASA Tweetup event held at NASA's Kennedy Space Center in Cape Canaveral, Fla, Sunday, Nov. 15, 2009. NASA Twitter followers in attendance will have the opportunity to take a tour of NASA's Kennedy Space Center, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. Photo Credit: (NASA/Carla Cioffi)