Millions of virtual rubberneckers spent Monday morning watching a cosmic collision, as NASA's Deep Impact spacecraft collided with comet Tempel 1. The deep-space smash was designed to give scientists a peak at the early solar system.

Internet users downloaded almost 80 million Web pages in the 24 hours starting at 8 p.m. EDT, Sunday, a one-day record for the NASA Web portal. The previous high was 30 million on Jan. 5, 2004, following the landing of the rover Spirit on Mars.

"We're extremely pleased so many people got to observe the Deep Impact mission as closely as the science team did," said David Mould, NASA's Assistant Administrator for Public Affairs. "Communicating the excitement of science and technology is one of our core missions, and this weekend the portal and Deep Impact teams achieved the same level of mission success on Earth as they did in space."

Internet users tuned in early to mission coverage and stayed throughout. During the 24-hour period, the portal transmitted 25 terabytes of information, more than five times the previous high. That's also nearly 30 times as much data as NASA's EOS-Terra spacecraft adds to its archive daily, and 1,250 to 2,500 times as much as astronomers daily get from the Hubble Space Telescope archive. The 25 terabytes, equivalent to 25 million megabytes, would fill a stack of CD-ROMs more than 170 feet high.

The portal also streamed NASA TV's mission coverage of the impact, peaking at 118,000 streams around the 1:52 a.m. EDT collision. The previous record of 49,672 streams also occurred on Jan. 5, 2004.

Like any collision, this one noticeably slowed traffic. The NASA portal team expected somewhat more traffic than in January, when the Cassini mission's Huygens probe landed on Saturn's moon Titan. Instead, demand was more than five times as high. The unexpected spike slowed down the portal's servers, but within 45 minutes technicians brought online an additional layer of computers to smooth out traffic flow.

The NASA Web Portal is managed jointly by the Office of Public Affairs and the Chief Information Officer. eTouch Systems, Freemont, Calif., is the prime contractor. Speedera Networks of Santa Clara, Calif., provided the caching services; Speedera was recently acquired by Akamai of Cambridge, Mass.

The NASA Web Portal is available online at:

http://www.nasa.gov

For more information about Deep Impact, visit:

http://www.nasa.gov/deepimpact