A Lockheed Martin Atlas 5 rocket kept its appointment to launch a television broadcast satellite that will serve million of homes across Europe, successfully roaring off a Florida launch pad Thursday on the exact minute scheduled months in advance.

A flawless countdown under beaming blue skies saw the 19-story rocket fueled with supercold fuel and readied for its mission to deliver the ASTRA 1KR spacecraft into orbit.

The Atlas program had amassed an enviable record of perfect launches dating back to 1993. A good flight Thursday would increase that tally to 79.

And Luxembourg-based satellite operator SES ASTRA is relying on the satellite to become a critical replacement in its space network, which provides more than 1,600 television and radio channels to 107 million households using a fleet of spacecraft.

At 4:27 p.m. EDT (2027 GMT), clocks reached zero and the main engine fired to full throttle. Moments later, a lone solid-fuel kick motor attached to the rocket's side was ignited for liftoff from Cape Canaveral's Complex 41.

Never before had an Atlas flown with such an unusual configuration. Rockets normally fly with either no strap-on boosters or else multiple ones. But the Atlas 5 vehicle was designed from its inception with the philosophy of each launch being tailored to the payload. If a cargo's weight needs the power of only one booster, then that's how the rocket will be built.

The solid booster's exhaust nozzle being aligned with the Atlas 5's center of gravity, coupled with steering control provided by the Russian-made RD-180 main engine, made Thursday's strange-looking ascent go smoothly. And officials note flying another solid motor to "even out" the appearance would make the rocket a bit more expensive and add worry about another part that must operate properly and then jettison to be successful.

While this was the first one-solid mission, two of the seven previous Atlas 5 launches flew successfully with uneven numbers of boosters attached to the first stage, including the commercial Inmarsat mission a year ago with two boosters strapped to the rocket's south side and one on the north; and January's New Horizons launch to Pluto with two on the south and three motors on the north.

The ASTRA 1KR mission was booked last year to launch on April 20 aboard an Atlas 5-411 rocket version, which translates to a four-meter nose cone covering the satellite, one solid rocket booster and a single-engine Centaur. And it was the first time an Atlas rocket had been picked to launch an ASTRA craft.

As the rocket sailed away Thursday, the solid booster completed its job and separated. The first stage fired for four minutes and then jettisoned, too. That left the Centaur to complete a pair of burns to inject the 9,548-pound satellite into a highly elliptical geosynchronous transfer orbit. That orbit's perigee, or low point, was much higher than usual to help save some of ASTRA 1KR's fuel supply, thereby increasing its life span by about two years.

ASTRA 1KR was released from the rocket over the Indian Ocean an hour and 48 minutes after liftoff, giving Atlas its 79th success in a row and sparking celebration back at Cape Canaveral.

"This is world's best launch team. Congratulations for another awesome performance," International Launch Services president Mark Albrecht told the Atlas team moments after spacecraft deployment.

"We are very proud and satisfied that the ASTRA 1KR mission has been a success," said Ferdinand Kayser, president and CEO of SES ASTRA. "The success of the ASTRA 1KR mission is a milestone in our company history and shows that we have strengthened the fruitful cooperation with our launch partners, Lockheed Martin and International Launch Services."

ILS markets the Atlas and Russian Proton rocket families, and Thursday's mission was the firm's 100th launch since forming in mid-1995. Ninety-seven of the launches have been successes; the three failures were Proton flights.

The Lockheed Martin-built ASTRA 1KR satellite will use an onboard engine over the next week to circularize its transfer orbit. Once in geostationary orbit, the solar array and antenna appendages will be deployed and then a week spent testing onboard systems. Handover of the satellite to operator SES ASTRA is expected around May 5, allowing controllers in Betzdorf, Luxembourg to perform an extensive checkout of the communications payload and positioning of the craft at its final orbital slot over the equator at 19.2 degrees East longitude.

Officials anticipate the satellite will enter commercial service on June 18, beginning a life of at least 15 years. It will replace the aging ASTRA 1B and ASTRA 1C spacecraft launched in 1991 and 1993, respectively.

"ASTRA 1KR will benefit our customers, further strengthen our unique inter-satellite backup scheme and provide important replacement capacity for our ASTRA 1B and ASTRA 1C satellites," Kayser said.

ASTRA 1KR was built using the A2100AX model design. It is equipped with 32 Ku-band transponders to transmit the programming directly to small receiving dishes on homes across Europe. Each of its transponders can relay 10 to 12 television channels.

Lockheed Martin is preparing for two more Atlas 5 launches this year, both for the U.S. military. An October 12 liftoff from Cape Canaveral will haul a batch of small spacecraft, including an experimental project to test in-space refueling of satellites. That rocket will be the 401 configuration with no solid-fuel motors. The year's manifest is slated to wrap up November 15 with the first West Coast flight for Atlas 5 from the refurbished Space Launch Complex 3-East at Vandenberg Air Force Base. A classified payload for the National Reconnaissance Office will ride aboard a 411-version rocket configured just like the one launched Thursday.