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Performing a successful spacelift mission for the U.S. spy satellite agency, an Atlas 5 rocket delivered a surveillance package into orbit today believed by analysts to be another pair of tandem sleuths to scoop up radio signals from adversarial ships at sea.

Liftoff came at 9:49:51 a.m. local time (12:49:51 p.m. EST; 1749:51 GMT) from Vandenberg Air Force Base in California as the 191-foot-tall vehicle headed for space on its 70th mission.

The kerosene-fed RD-180 main engine powered the rocket off the pad at Space Launch Complex 3-East on South Vandenberg with 860,000 pounds of thrust.

It was a four-minute flight for the first stage before the cryogenic Centaur upper stage took over. The mission went into a news blackout once the 14-foot-diameter nose cone enclosing the payload was jettisoned about five minutes of liftoff.

The Centaur likely conducted two firings separated by a long coast period to achieve the 63-degree orbit for release of the payloads, thought to be two formation-flying satellites that will operate 700 miles above Earth.

The discard stage then was expected to be de-orbited into the Pacific, several hundred miles off Chile, to avoid space junk and a future uncontrolled re-entry.

But analysts and satellite observers agree that today’s launch marked the eighth time since 2001 than an Atlas rocket of some configuration has deployed satellites to refresh the Naval Ocean Surveillance System, or NOSS. It was ULA’s fifth NOSS launch.

“NOSS satellites locate and track ships at sea by detecting their radio transmissions and analyzing them using the TDOA (time-difference-of-arrival) technique,” said Ted Molczan, a respected monitor of spacecraft.

“Normally, under favorable circumstances, these satellites reach magnitude +5, observable with 7×50 binoculars. Occasionally, they brighten to magnitude +2 to +4, readily visible to the un-aided eye. Rarely, they rival the brightest stars.”

Atlas launches for NOSS over the last 15.5 years have come from both Vandenberg and Cape Canaveral in Florida. This was the sixth to originate on the West Coast, and NOSS was the original customer that sparked revitalization of the SLC-3E pad in the late 1990s.

The current era is distinguished by two satellites, launched by the same rocket, working in tandem. The pairs of satellites, weighing an estimated 14,000 pounds at launch, orbit in close proximity to each other as they circle the Earth.

Previous generations of NOSS missions featured three satellites working as triplets. There were 11 of those launches to reach orbit between 1976 and 1996.

The NRO is the secretive government agency responsible for the country’s fleet of spy satellites. Agency officials don’t publicly disclose the identities or uses of satellites carried aboard its launches.

The NRO was created in 1961 and operated in total secrecy as a black organization until its existence was declassified in 1992. It began acknowledging in advance the launches of its payloads in 1996.

Today, the agency operates imaging and eavesdropping spacecraft, naval surveillance birds and data-relay satellites for the constellations.

The satellites serve as the country’s eyes and ears, operating in various orbits, to collect data for civilian leadership and warfighters.

“These systems provide the foundation for global situational awareness, and address the nation’s toughest intelligence challenges. Frequently, NRO systems are the only collectors able to access critical areas of interest, and data from overhead sensors provides unique information and perspectives not available from other sources,” according the agency.

“The NRO’s key customers and mission partners include: policymakers, the armed services, the intelligence community, Departments of State, Justice and Treasury, and civil agencies. All of them depend on the unique capabilities NRO systems provide.”

NRO duties range from monitoring the proliferation of weapons of mass destruction and tracking international terrorists to developing highly accurate military targeting data and bomb damage assessments.

“With its vigilance from above, the NRO gives America’s policymakers, intelligence analysts, warfighters and homeland security specialists the critical information they need to keep America safe, secure and free,” the NRO says.

The NRO has at least four more launches planned this year.

Today marked the 141st successful Atlas program launch in a row spanning more than two decades, the 70th for an Atlas 5 and the 117th in 123 months for United Launch Alliance.

In its 70 trips to space, the Atlas 5 has performed 26 flights dedicated to the Defense Department, 16 commercial missions, 14 for NASA and 14 for the National Reconnaissance Office.

This was the 46th time that the NRO had acknowledging one of its launches in advance since starting that practice in 1996, and the 24th to fly from Vandenberg.

** ATLAS 5 LAUNCHES FOR NRO **

AV-009: NROL-30 using Atlas 5-401 (June 15, 2007) Cape

AV-015: NROL-24 using Atlas 5-401 (Dec. 10, 2007) Cape

AV-006: NROL-28 using Atlas 5-411 (March 13, 2008) Vandenberg

AV-025: NROL-41 using Atlas 5-501 (Sept. 20, 2010) Vandenberg

AV-027: NROL-34 using Atlas 5-411 (April 14, 2011) Vandenberg

AV-023: NROL-38 using Atlas 5-401 (June 20, 2012) Cape

AV-033: NROL-36 using Atlas 5-401 (Sept. 13, 2012) Vandenberg

AV-042: NROL-39 using Atlas 5-501 (Dec. 5, 2013) Vandenberg

AV-045: NROL-67 using Atlas 5-541 (April 10, 2014) Cape

AV-046: NROL-33 using Atlas 5-401 (May 22, 2014) Cape

AV-051: NROL-35 using Atlas 5-541 (Dec. 13, 2014) Vandenberg

AV-058: NROL-55 using Atlas 5-401 (Oct. 8, 2015) Vandenberg

AV-065: NROL-61 using Atlas 5-421 (July 28, 2016) Cape

AV-068: NROL-79 using Atlas 5-401 (March 1, 2017) Vandenberg

NROL-79 was the first of back-to-back NRO missions by Atlas 5 from the West Coast. NROL-42 is planned for June using a powerful variant with four strap-on solid rocket boosters.

“We are already pressing on with L-42,” said Lt. Col. Eric Zarybnisky, 4th Space Launch Squadron commander and the Air Force launch director at Vandenberg. “We have received the booster and some other flight hardware. So we will launch L-79 and roll right into L-42. In fact, we are going to start working L-47, a Delta out here, shortly after that. So no rest for the weary here at Vandenberg for a little while.”

The next Atlas 5 will occur from Cape Canaveral on March 19 to send a commercial cargo ship to the International Space Station.

See earlier NROL-79 coverage.

Our Atlas archive.