When a NASA astronaut sent the first direct-to-Internet tweet from space earlier this year, Citrix technology was behind it, the software vendor said this week.

The Crew Support LAN -- first used last month on Expedition 22 of the International Space Station -- uses Citrix's high-definition XenDesktop to give astronauts direct and private access to some desktop applications and Web sites from any location.

The network also uses WAN optimization technology from Citrix Branch Repeater to secure communications from the LAN, according to Citrix. Branch Repeater provides WAN optimization so branch-office and mobile users can remotely access high-definition desktops.

The XenDesktops are managed and secured in a data center on the ground. Space station crew members access the remote desktops by using laptops from their location.

Before NASA deployed Crew Support LAN, astronauts who wanted to send an update to an online application like Twitter or e-mail had to first manually send the signal to ground personnel before it could be sent to the Web.

By using XenDesktop with Branch Repeater, NASA was able to reduce bandwidth requirements and optimize the performance of high-latency satellite communication, according to Citrix.

Crew Support LAN is part of a project by NASA to create a better quality of life for astronauts during long-duration space missions, allowing them to perform some tasks the way they might in their daily lives on Earth.

NASA has been ramping up its use of multimedia Web applications from space. In addition to tweets from the space station, NASA also sponsored a live Twitter chat with an astronaut on the space shuttle Endeavor in February.

NASA also streamed live video of astronauts working inside the space station in February, powered by a high-speed communications antenna and NASA's Tracking and Data Relay Satellite System.