Sunday, September 24, 2017

ULA Atlas V Places NROL-42 Classified Payload into Orbit

A United Launch Alliance (ULA) Atlas V rocket carrying a payload for the National Reconnaissance Office lifted off from Space Launch Complex-3. Designated NROL-42, the mission is in support of national security. Photo & Caption Credit: Jeff Spotts / ULA

A United Launch Alliance (ULA) Atlas V 541 rocket has successfully lifted off from Launch Complex 3 at the Vandenberg Air Force Base in California to deliver a classified satellite into orbit for the National Reconnaissance Office (NRO). In spite of only a 60 percent chance of favorable weather conditions, at T-minus zero, the conditions were acceptable and the NROL-42 launch occurred on schedule.

Producing some 2.4 million pounds-force (10,580 kN) of thrust at liftoff, the Atlas V rocket lit up the night sky over California as it sped away from the launch pad at 10:49 p.m. PDT on September 23 (1:49 a.m. EDT / 05:49 GMT Sept. 24), 2017.

The 4 Aerojet Rocketdyne AJ-60A solid rocket boosters (SRBs), along with the core stage’s single RD-180 engine accelerated the vehicle to Mach 1 in just 34 seconds.

At 47 seconds into the flight, the vehicle reached Max-Q, the point at which aerodynamic stress on a vehicle in atmospheric flight is maximized.

Having completed their work, the SRBs burned out 1 minute and 38 seconds into the flight; the first two SRBs were jettisoned 13 seconds later, with the second pair just one-and-a-half seconds after that.

The first stage’s single RD-180 engine, burning through its supply of rocket grade kerosene (RP-1) and liquid oxygen (LOX) at a rate of some 2,320 pounds (1,052 kg) per second, continued to push the vehicle away from its home planet.

Three minutes, twenty-four seconds into the flight, with the vehicle over seventy-five miles high and one-hundred and thirty-five miles downrange, and traveling over 8,000 miles per hour (12,875 km/h), the payload fairing jettisoned, thereby exposing the payload to space. The atmosphere is so thin at this altitude that it posed no danger to the spacecraft.

About 6 seconds following main engine cutoff (MECO), the second stage separated and fired its single Aerojet Rocketdyne RL-10C engine, propelling the spacecraft into its 63 degrees inclination orbit.

As is customary with NRO launches, the launch coverage ended before completion of the flight.

Laura Maginnis, ULA vice president of Government Satellite Launch, said: “Congratulations to the entire team for overcoming multiple challenges throughout this launch campaign. From Hurricane Irma schedule impacts to replacing to a first stage battery this week – the team maintained a clear focus on mission success.

“NROL-42 marks the 25th ULA-launched NRO mission, building upon our legacy of partnership with the NRO in providing reliable access to space for our nation’s most critical missions.”

The classified payload, rumored to be a signal collecting surveillance satellite, Trumpet Follow On 2, along with the spacecraft’s secondary instrument package, a Space-Based Infrared System Highly Elliptical Orbit (HEO-4) deployed successfully, according to ULA.

After first stage separation, ignition of the Centaur upper stage, and separation of the shroud, the launch went into a news blackout five minutes into the flight, the standard operating procedure for NRO missions. A successful launch was announced via a press release about two hours later. The HEO instrument is a space-based system capable of detecting missile launches that occur in Northern Latitudes.

Colonel Greg Wood, the 30th Space Wing vice commander and was the Space Launch Commander, said: “Team members of the 30th Space Wing, our partners at the National Reconnaissance Office, and United Launch Alliance worked together to ensure the success of this critical mission. This unified effort is what delivers the essential reconnaissance capability to the nation.”

The 30th Space Wing at Vandenberg Air Force Base maintains the safety procedures and launch operations from the Western Range.

“We’ve worked diligently over the course of many months to conduct mission assurance for launch site operations and reduce technical risk,” said Lt. Col. Kenneth Decker, 4th Space Launch Squadron commander. “We are very proud to be part of the team that contributed to the success of this mission.”

The launch, previously scheduled for September 11, was postponed to allow launch personnel, who work Atlas V launches at Both Vandenberg and Cape Canaveral, to return home to Florida to make preparations for Hurricane Irma.

This was ULAs sixth launch of 2017, their twenty-fifth launch in support of the National Reconnaissance Office, and the seventy-third launch of the venerable Atlas V booster.

Written by: Lloyd Campbell
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