Although the crew of the spacecraft Endeavour experienced a glitch in the first space walk when an astronaut accidentally let her tool bag float away, NASA had a lot to celebrate as it announced success with a high-tech space program.
NASA, along with Vinton Cerf, a Google vice president, successfully tested a deep-space network modeled after the Internet. Engineers from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., have transmitted dozens of images to and from the spacecraft located 20 million miles from Earth using disruption-tolerant networking (DTN) software.
DTN, which sends information differently from the TCP/IP protocol used by the Internet, was developed a decade ago by NASA engineers and Cerf, who is known to many as the "father of the Internet" and is a visiting scientist at JPL.
"This is the first step in creating a totally new space communications capability, an interplanetary Internet," said Adrian Hooke, team lead and manager of space-networking architecture at NASA.
The month-long experiment is the first of many planned tests to qualify the technology for use on future space missions. If NASA continues to succeed with DTN, astronauts on manned missions will be able to communicate with researchers worldwide. NASA is planning its next round of testing next summer, using DTN software on the International Space Station.
"We have been doing this test for a month and it has been working well and it's exciting getting the word out that we had a good round of testing," said Leigh Torgerson, manager of the DTN experiment operations center at JPL, in a phone interview.
"We needed some way of automating the data routing process in a standard way so any other space agency can pick up the protocol and use it," Torgerson said. "The more nodes you have, the more paths you have to get data back and the easier it is to receive the data."
Like the Endeavour team's first walk, not everything in the testing went off without a hitch. "There was an unexpected uplink system failure at one of the deep-space network sites, which interrupted some file transfers, and the DTN protocol took care of retransmitting the missed data automatically so nothing was lost," Torgerson said.
Securing the Network
The next step for the team at JPL is to add additional applications to the DTN, according to Torgerson. Also on the to-do list for JPL is to test the security and authentication protocols.
"Authentication is very important. It is really easy for a ham radio hacker to put his antenna up in his backyard (and try to join the network)," Torgerson added. "You have to be able to protect someone from sneaking into your network."
Each node in the network will have its own authentication protocol and will be able to authenticate a bundle or quantum data similar to packets on the Internet. Each node will have bundled authentication capabilities to be sure that data is from an authorized sender.
"Of course, the vision for us is once we get this in place every spacecraft will have a DTN capability and will be able to form a much richer network and cut out a labor-intensive process," Torgerson said.
Earth vs Space
Unlike TCP/IP, cocreated by Cerf, DTN does not rely on an end-to-end connection. If a destination path cannot be found, the data packets are not discarded. Each node instead holds on to the information until it can communicate with another node, and therefore no information is lost when there is no immediate connection.
NASA uses the analogy of basketball players passing the ball to the player closest to the basket to describe DTN's store-and-forward method.
Google referred all questions about the test to NASA, "since Google didn't directly collaborate with NASA for this project," according to Andrew Pederson, a Google spokesperson.