This map illustrates the planned imaging coverage for the NASA Descent Imager/Spectral Radiometer aboard ESA's Huygens probe during its descent toward Titan's surface on Jan. 14, 2005. The colored lines mark the observation area as the probe descends. The yellow dot is the planned landing zone.
DARMSTADT, Germany -- Europe's Huygens probe has successfully negotiated its descent to the surface of Saturn's mysterious moon, Titan, with its experiments switched on and continuing to collect data for two hours after its landing on what is probably a hard surface, Huygens program managers said.
U.S. and European officials had trouble holding back tears as they learned the news after long minutes of tense staring into computer screens at mission control center here.
"We have a scientific success,'' European Space Agency (ESA) Director-General said in a press briefing. "We will now be able to start breaking Titan's secrets."
ESA science team members said Huygens landed on Titan between 1345-1346 local time here (CET), which was about 7:45-7:46 a.m. EST. It took signals just over an hour to traverse the vast distances between Titan and Earth.
Originally expected to send perhaps 2.5 hours worth of data to the NASA's Cassini orbiter for later delivery to Earth, Huygens was still sending signals five hours after activation, and researchers said the probe's robust battery could last up to seven hours total.
Huygens has also been sending limited data directly to Earth, where it has been picked up by a network of telescopes. The detailed data about what it found on its way through Titan's thick atmosphere has been sent to NASA's Cassini orbiter overhead.
Mission managers have reported only one single glitch in Huygens' data return. A redundant transmission channel is apparently not working properly, but only one of the probe's six instruments - a Doppler tool to study Titan's winds - is dependent solely on that channel and may be compensated for by data from ground-based observations, mission scientists said.
NASA's Cassini orbiter has also sent an initial data set of its own to ground teams. It will be several hours more before scientists decipher this information. But the mission has already cleared several of its biggest hurdles and has demonstrated enough to be declared a major event in the history of space science.
"This is a historic event," ESA Science Director David Southwood said. "The torch has now been passed from the engineers who delivered the probe and got the data sent to Cassini to the scientists who will evaluate the data."
Choking back tears, NASA Associated Administrator Al Diaz, who worked on the Cassini-Huygens mission for years before taking up his current post, said "It's up to ESA to take this data and turn it into science."
Diaz and Dordain embraced after they learned that Huygens' initial data was received by Cassini and ground telescopes confirming the initial success of the mission.
Officials said Cassini would continue to send its data packets in the coming hours. It is this data that will disclose details of what Huygens saw on its two-hour descent.
SPACE.com Staff Writer Tariq Malik contributed to this report from New York City.
SPACE.com Special Report: Cassini-Huygens at Saturn and Titan