At the end of an era in American rocketry, United Launch Alliance launched its 16th and final Delta 4 Heavy triple-core rocket on Tuesday, launching a secret spy satellite in the latest installment of a family of rockets dating back to the dawn of the Space Age.
The three hydrogen-fueled RS-68A first stage engines ignited with a burst of bright orange flame at 12:53 p.m. EDT, seamlessly propelling the 235-foot-tall rocket off Pad 37 at Cape Canaveral Station. For the Florida Space Force.
United Launch Alliance
The launch was 12 days late, mainly due to work to replace a pump in a system that supplies nitrogen gas to multiple launch pads from a pipeline that runs through Kennedy Space Center and Cape Canaveral Space Force Station. There were no problems on Tuesday.
Mounted atop the rocket was a secret satellite provided by the National Reconnaissance Office, a secret government agency that operates the country's fleet of advanced optical and radar reconnaissance satellites and electronic eavesdropping stations.
In keeping with joint NRO-US Space Force policy for such missions, there are no details about Payload NROL-70 Released. But about six hours after launch, the National Reconnaissance Office declared the launch a success, indicating that the satellite had reached its planned orbit.
“All of our missions are really important, and this one is number one,” NRO Director Chris Schooles told reporters before the rocket's initial launch attempt. “But it's a little more special because it will be the last flight of a Delta 4 Heavy.
“As with all of our missions, it is focused on national security and providing the best information, we believe, in the world to our policymakers, warfighters and civil society.”
Based on the heavy vehicle's eastern trajectory, safety notices and other factors, independent analysts concluded that the payload was most likely an advanced signals intelligence satellite headed for geosynchronous orbit 22,300 miles above the equator.
Satellites at this altitude appear fixed in the sky because they rotate in sync with the Earth's rotation, allowing continuous monitoring of specific areas.
Such signals intelligence satellites are believed to have giant grid antennas that unfold in space and act as huge “ears” in the sky, monitoring large areas for radio emissions, especially military (communications),” according to Marco Langbroek, one of the intelligence researchers. An independent analyst based in the Netherlands.
In response to a specific question about the nature of the NROL-70 satellite, Scoles told reporters, “There's not much I can say other than it's a national security payload that will provide a fantastic capability that a lot of people and organizations need.” Obviously policymakers, fighters and others so they can know what's going on.”
However, as is standard practice for classified missions, ULA ended launch coverage by confirming second-stage engine ignition and payload separation seven minutes after liftoff. The rest of the ascent was carried out in secrecy.
The final appearance of the Delta rocket 63 years after the first version's first flight was an emotional milestone for the managers, engineers and technicians who assembled and launched the last member of the family.
“The launch of the last Delta 4 is bittersweet for me,” Col. Eric Zarebinski, director of the NRO’s Space Launch Office, said in a statement. “I was part of the team that launched the first Delta 4 for the NRO. Since that time, Delta 4 has put an amazing capability into orbit for this nation.”
Tory Bruno, president and CEO of United Launch Alliance, also called the flight a “bittersweet” moment as the company continues its transition to the next generation of Vulcan rockets, phasing out the more expensive Delta and Atlas families.
“Soon, Vulcan will take up this mantle and we will retire this venerable rocket that has done so much important work for our country,” he said after the launch in a pre-recorded video.
“I would like to thank everyone involved in the Delta 4 Heavy launch. We have many employees who were here for the first Delta 4 launch and are still here now for the last Delta 4 launch to send this amazing vehicle into its well-earned retirement.”
He told reporters earlier that closing the Delta line “is definitely the future, and moving to Vulcan, which is a lower-cost, higher-performance rocket. But it's still sad.”
The single-core Delta 4 and triple-core Heavy were expensive, with some versions of the Heavy reportedly selling for over $300 million each. Despite its ability to place high-priority military payloads into complex, hard-to-reach orbits, the program was not considered sustainable in the age of smaller, more numerous satellites and low-cost boosters from SpaceX.
The Delta family of stages and rockets has its roots in the early space program, first serving in the nation's fleet of intermediate-range ballistic missiles and evolving through multiple versions used to place military, NASA, and civilian payloads into orbit.
The now-retired Delta 2 debuted in 1990, putting the first Global Positioning System satellites into orbit and sending multiple planetary probes into deep space, including Messenger to Mercury, several Mars orbiters, and the Pathfinder, Spirit, and Opportunity Mars rovers And the Spitzer Space Telescope. And much more.
The single-core Delta 4 first flew in 2002, followed by the first heavy rocket two years later. The single-core version flew the program's final flight in 2019. Tuesday's launch was the 45th flight of a Delta 4 and the 16th and final flight of a Delta 4 Heavy.
“We're very excited to come with Vulcan and do these missions, but at the same time, we love this rocket,” Bruno said of the Delta family.
“Delta has been around in one form or another for 60 years,” he added. “Vulcan has a rich legacy and has done great things for our nation. We are very proud to have been a part of that, and even though Vulcan is the future, I am personally sad to see it go,” he added.
