Powerful Atlas 5 rocket boosts Navy comsat into space

A powerful United Launch Alliance Atlas 5 rocket lifted a sophisticated Navy communications satellite into orbit Friday, the fifth and final member of a $7.7 billion constellation designed to provide 3G-class cellular capabilities to troops around the world.

Under a clear blue sky, the Atlas 5's Russian-built RD-180 first stage engine roared to life on time at 10:30 a.m. EDT (GMT-4) followed by ignition of five solid-fuel strap-on boosters that quickly pushed the rocket away from pad 41 at the Cape Canaveral Air Force Station.

Initially climbing straight up atop 2.6 million pounds of thrust, the 206-foot-tall rocket gracefully arced away to the East and accelerated toward space leaving a churning cloud of exhaust in its wake. Spectacular rocketcam views looking down on the Cape Canaveral coast showed launch pads and the old shuttle runway dropping away below.

The strap-on boosters burned out and fell away in sequential fashion about one minute and 50 seconds after liftoff. The RD-180 continued firing for another two-and-a-half minutes before shutting down as planned. The first stage then fell away, the Aerojet Rocketdyne RL10C-1 engine powering the Centaur second stage ignited and the climb to orbit continued.

During the Atlas 5's most recent previous flight, a March 22 mission to boost a space station cargo ship into orbit, the RD-180 shut down six seconds early because of problems with a propellant mixture control valve. The second stage engine burned longer to compensate and the Orbital ATK cargo ship reached the required orbit.

ULA and NPO Energomash carried out a detailed investigation that identified the problem. It was corrected, officials said without providing any details, the rocket was cleared for launch and the engine fired normally Friday.

The second-stage engine completed the first of three planned "burns" about 12-and-a-half minutes after liftoff, putting the vehicle into a preliminary orbit. Two additional second-stage firings were needed to put the satellite payload into the required elliptical "geostationary transfer" orbit with a low point of some 2,386 miles and a high point of around 22,187 miles.

The flight plan called for the Navy's fifth Mobile User Objective System -- MUOS -- satellite to be released about two hours and 53 minutes after launch.

If all goes well, the 7.5-ton spacecraft's on-board thrusters will raise the low point of the ellipse, putting MUOS 5 into a circular orbit 22,300 miles above the equator. At that altitude, satellites take 24 hours to complete one orbit and thus appear stationary in the sky.

Flight controllers then will oversee deployment of a 17-foot-wide gold mesh antenna designed to send and receive signals from ground terminals that currently send voice and data through older Ultra High Frequency Follow-On, or UHF, satellites.

A much larger 46-foot-side antenna will provide the equivalent of 3G-class cellular network-type communications.

"Launch of MUOS 5 is a major milestone for the MUOS program and the Navy, as well as the rest of the armed forces that'll be utilizing this satellite constellation," said Mark Woempner, MUOS program manager for satellite-builder Lockheed Martin.

"As a retired Army colonel who led soldiers in theater in Iraq, I can tell you first hand MUOS is a game changer. Communications for our service men and women will change drastically."

MUOS satellite provide "beyond-line-of-sight communications," allowing soldiers to make encrypted smartphone-like calls to nearly anywhere in the world, handling simultaneous text and video. MUOS 5 will serve as an orbital spare to the four currently operational relay stations.

"MUOS is a global military cellular network," Woempner said. "Users will be able to talk with crystal clear, recognizable voice but also will be able to text, email, call the DSN (defense switching network) office phone, browse (military networks), transfer imagery or mission data as needed.

"This is all done on a high-speed internet protocol based system," he said, adding that MUOS technology "brings greatly improved connectivity inside the challenging terrain as forests, mountains, urban environments. You won't have to come out from under cover to make a call anymore."

Next up for ULA's Atlas 5: launch of a classified military satellite from Cape Canaveral on July 28 followed by launch of NASA's OSIRIS-REx asteroid sample return spacecraft on Sept. 8.