A launch of the Delta 4 Heavy Alliance, one of the most powerful rockets in the US inventory. UU., It shot off the coast of California over a torrent of blazing fire on Saturday, hosting a spectacular show as it propelled a clbadified spy satellite from the National Reconnaissance Office into orbit.
More than a month late due to climatic and technical problems, the hydrogen-powered engines at the base of the three common-core impellers from side to side of the Delta 4 went on at 11:05 am PST (GMT-8) , breaking the morning Cálmese with a thunder of bright orange flames and billowing clouds of exhaust.
An instant later, the 23-story-tall orange-and-white rocket was launched from launch complex 6 at Vandenberg Air Force Base in northwest Los Angeles and the huge propeller began to accelerate to the sky at 2.1 million pounds. of push.
The spectacular views of "rocketcam" showed that the California coast descended below with the tip of the Earth and the deep black of the space that was quickly seen.
The first moments of the flight seemed normal when the rocket left the dense lower atmosphere, arching south over the Pacific Ocean. The two lateral thrusters went out and fell as expected, approximately four minutes after takeoff.
The Aerojet Rocketdyne RS-68A engine of the central booster engine continued firing for another minute and a half before it also went out and away from the fast-moving second stage. A few seconds later, the only RL10B-2 engine in the upper stage ignited to continue the ascent into space.
Now, well away from the lower atmosphere, the protective cone around the payload of the secret satellite split and came off, exposing the spacecraft to space. And at that moment, as usual in the NRO clbadified missions, United Launch Alliance finalized the video coverage and comments.
While details of the NROL-71 mission have not been released, independent satellite badysts said late last year that it could be an advanced 5 KH-11 optical image recognition satellite.
These satellites normally launch in "sun-synchronous" orbits tilted approximately 97 degrees towards the equator, which ensures that the spacecraft pbades through all points of the globe, at the same time and with similar lighting conditions, as the planet turn next.
But based on a variety of factors, including safety warnings about where the second stage of Delta 4 was predicted to fall back into the atmosphere after satellite separation, it appears that the satellite was destined to an orbit with an inclination of approximately 74 degrees, one that would allow images in a variety of lighting conditions.
As with all these launches, a group of veteran amateur satellite trackers from around the world planned to be on call in the coming days and weeks, looking for the payload of NROL-71 as it pbades to the head to get Additional details about its orbit and, in turn, what kind of mission it might be carrying out.
Whatever it is, the satellite had a longer wait than usual for the launch.
An initial launch attempt was canceled on December 7 due to a telemetry problem and the next day it stopped at the T-minus mark of 7.5 seconds due to an intermittent signal on another system.
A third launch attempt on December 18 was stopped due to strong winds and a fourth attempt the next day was rubbed when the sensors detected hydrogen concentrations higher than those allowed in the engine compartment of the first stage of the rocket. Engineers eventually traced the problem to a leaking valve, clearing the way for Saturday's launch.