Atlas V launch with classified satellite on track

• Florida Today will have live coverage of the Atlas V rocket launch today beginning at 4%3A30 p.m.

Update, 2:57 p.m. ET:

Tonight's planned launch of an Atlas V rocket carrying a secret U.S. government satellite from Cape Canaveral Air Force Station remains on track, but weather is iffy.

The forecast calls for a 60 percent chance that poor weather will prevent the launch during the nearly two-and-a-half hour window, which opens at 5:44 p.m. tonight.

Tune in to live updates on the launch at FloridaToday.com/Space

Original story:

Global Positioning System satellites help us figure out where we are during hikes, bikes, drives and boat rides.

The same technology now also is tracking the flights of space-bound rockets, including a United Launch Alliance Atlas V set to lift off at 5:44 p.m. Tuesday with a secret U.S. government satellite, to ensure they stay on course.

"It's actually very similar to what's in your car," Dillon Rice, a range operations engineer with ULA, said of the rocket's GPS tracking system. "We're talking to the same satellites."

Tuesday's forecast is iffy, with a 40 percent chance of favorable weather during a nearly two-and-a-half-hour window at Cape Canaveral Air Force Station's Launch Complex 41.

The payload is a classified Lockheed Martin-built communications satellite referred to as CLIO, a mission not publicly attributed to any military or intelligence agency.

The 19-story rocket will be the first Atlas V to use GPS signals as a primary source of information that enables the Air Force to confirm the rocket is flying where it should — southeast over the Atlantic — and not endangering the public.

Two previous Atlas V missions tested the system, but Tuesday's is the first flying without a beacon on the rocket to communicate with ground radars that until now were required for launches to proceed.

That became a problem earlier this year when fire damaged a local radar station, forcing the Eastern Range to shut down for about two weeks while a replacement radar was brought online to support another Atlas V launch.

"The nice thing about the GPS metric tracking system is that we're no longer reliant on the radars," said Rice, a 39-year-old Merritt Island resident. "It increases our launch availability."

The GPS data supplements telemetry generated by the rocket's flight computers, providing range safety officers with the two independent sources they need to ensure public safety.

Based on these inputs, the Mission Flight Control Officer determines whether or not a vehicle needs to be destroyed to protect the public, said a spokesperson at the Air Force's Space and Missile Systems Center, which oversees range operations.

Some radars continue to provide a third tracking source by operating in "skin track" mode, in which they look for reflections off the rocket rather than directly pinging a beacon.

MORE PHOTOS: Atlas V rolls out to launch pad

But the Air Force says its reduced need for a network of costly radars could save as much as $1 million a year.

ULA's Atlas V rockets — about to fly for the 49th time — are transitioning to GPS tracking after the company's Delta IV rockets, which have already flown the systems seven times.

During some launches, Rice monitors the health of the rocket's telemetry systems and sees a map displaying its speed and position in real time — more accurately than radar views. Tuesday, he's the host of ULA's launch Webcast.

Rice grew up near Jacksonville watching "Star Trek" episodes and shuttle launches on TV. One childhood visit to the Space Coast ended with a scrubbed rocket launch; another time the family was passing through the area and heard the sonic booms of a returning shuttle.

After earning an electrical engineering degree at the University of North Florida, Rice joined Boeing in 1999 to help build the new Delta IV launch complex. Boeing and Lockheed Martin merged the Atlas and Delta families to form ULA in 2006.

"It's really exciting to watch each countdown progress and see the engines ignite and the vehicle take off," he said. "It's not something that you ever get tired of seeing."

Contact Dean at 321-242-3668 or jdean@floridatoday.com.

Rocket: Atlas V "401"

Mission: CLIO (classified)

Launch Time: 5:44 p.m.

Launch Window: to 8:10 p.m.

Launch Complex: 41 at Cape Canaveral Air Force Station

Weather: 40 percent "go"

Visit floridatoday.com for live countdown coverage starting at 4:30 p.m.