With the NRO spy satellite, a Delta 4-heavy rocket takes off.

The second-to-last flight of the Delta rocket from United Launch Alliance took off from Cape Canaveral in the early hours of Thursday. It put a top-secret spy satellite for the U.S. government into orbit, breaking the longest lull in launches in ULA’s history.

At 5:18 a.m. EDT (09:18 a.m. UTC) on Thursday, Pad 37B at Cape Canaveral Space Force Station served as the launch pad for ULA’s 15th Delta 4-Heavy rocket and 44th Delta 4 rocket overall. Due to inclement weather, the launch team at ULA had to extend the launch time by more than 90 minutes on Thursday.

Due to a problem with a valve in a ground pneumatics system, the mission’s first launch attempt on Wednesday morning was aborted.

A classified payload was carried into orbit by the 235-foot-tall, 71.6-meter Delta 4-Heavy rocket for the National Reconnaissance Office, the U.S. government’s spy satellite agency. Expert observers of military space missions believe that the Delta 4 rocket launched a large spacecraft intended to intercept U.S. adversaries’ telephone calls, data transmissions, and other forms of communication. Although the NRO does not officially disclose the specifics of its satellites, they do believe that the Delta 4 rocket did so.

Due to the launch’s due east trajectory and the Delta 4-Heavy used, it appears that a spy satellite known as an “Advanced Orion” or “Mentor” was aboard Thursday’s launch. The Advanced Orion satellites are in a geosynchronous orbit that closely hugs the equator and covers more than 22,000 miles (nearly 36,000 kilometers). The satellites move in sync with the Earth’s rotation in that orbit, providing them with constant coverage of the same regions of the globe around the clock.

The Delta 4-Heavy rocket’s lift capability, long-duration upper stage, and enormous 65-foot (19.8-meter) trisector payload fairing are all necessary for the Advanced Orion satellites.

The eight and a half-hour countdown that began Wednesday night was overseen by ULA’s launch team at the Delta Operations Center in Cape Canaveral. After sunset, technicians removed the Delta 4’s 330-foot-tall service gantry to make room for the rocket’s loading of super-cold liquid hydrogen and liquid oxygen.

In the wake of ticking down the last minutes until takeoff, the Delta 4-Weighty rocket terminated its three RS-68A motors provided by Aerojet Rocketdyne and flew east from Cape Canaveral controlled by 2.1 million pounds of pushed. The two side boosters of the Delta 4’s hydrogen-fueled engines burned for nearly four minutes before the side boosters descended away from the core booster of the Delta 4. After the two side boosters were detonated, the core stage’s engine was turned up to continue accelerating into space after being throttled down for the first few minutes of the flight to conserve propellant.

About five and a half minutes into the mission, the core stage shut down its engine. The center booster was then separated, and the Delta 4’s upper stage’s Aerojet Rocketdyne RL10 engine was ignited. The NRO spacecraft was covered by the metallic payload fairing of the rocket as it passed through the atmosphere, but it was jettisoned more than six and a half minutes after liftoff to reveal the NRO’s newest spy satellite to the outside world for the first time.

The mission entered a government-imposed news blackout at that time. The remainder of the Delta 4’s climb to geosynchronous orbit took place secretly after ULA’s live launch broadcast ended. The Delta 4 was expected to deploy the NRO spy satellite into a nearly circular geosynchronous orbit that was more than 20,000 miles above the earth in about six hours. The upper stage RL10 engine probably needed three burns to accomplish this.

In a statement released just before 12 p.m. EDT (1600 UTC) on Thursday, the NRO and ULA confirmed that the launch was successful. The government agent satellite office, which assigned the mission NROL-68, unveiled no insights regarding the payload.

According to a statement released by the NRO, “The NROL-68 mission is the latest national security payload to deliver critical intelligence information from space that our warfighters and decision makers need.” The largest and most capable overhead constellation in NRO history, which serves as the foundation for America’s advantage and strength in space, is still being developed by NRO.

Chris Scolese, director of the NRO, stated, “Today’s mission is another example of how the NRO continues to go above and beyond.” In order to keep the United States of America as the undisputed leader in space, our architecture is changing. The capacities we are placing into space grow our insight advantage and empower us to follow through on our main goal of guarding America.”

The Advanced Orion satellites from the NRO are among the largest spacecraft ever launched. Ted Molczan, an authoritative skywatcher who keeps track of satellite activity, says that they shine with the brightness of an 8th magnitude star when seen from Earth, making them easy to see with small binoculars despite their distant orbits.

After taking off from Cape Canaveral, the four previous Delta 4-Heavy launches—in 2009, 2010, 2012, 2016, and 2020—followed similar trajectories and carried classified cargo for the National Reconnaissance Office. All, according to independent analysts, sent secret NRO eavesdropping satellites into space.

Bruce Carlson, the then-director of the NRO, referred to the payload as “the largest satellite in the world” prior to the alleged launch of an Advanced Orion satellite in 2010. It is believed that the satellites are equipped with enormous antennas that, once in space, expand to a diameter of up to 328 feet (100 meters).

It is possible to tune the antenna to listen in on communications between adversaries of the United States. The latest Advanced Orion satellite’s coverage area, whether it will replace an older satellite or expand the NRO’s eavesdropping network, and other details are unknown.

Following two earlier NRO Orion payloads that were launched in the 1980s on space shuttle missions, the Advanced Orion series of satellites began launching in 1995 on Titan 4 rockets. After the Titan 4 booster was retired, the NRO began using Delta 4-Heavy rockets for the Advanced Orion missions in 2009.

Additionally, the NRO has a fleet of close-to-Earth optical and radar spy satellites. Additionally, Delta 4 rockets were used to launch many of those.

The imagery and intelligence data gathered by the spy agency’s satellites help military commanders, senior policymakers, and the president make better decisions.

The Delta family of rockets will be replaced by the new Vulcan launch vehicle, which will make its first test flight later this year from Cape Canaveral. ULA is a 50/50 partnership between Boeing and Lockheed Martin. ULA’s Atlas 5 launcher will also be replaced by the Vulcan rocket, which will fly 19 more times before retiring in the 2020s.

The Chart book 5 and Delta 4 rockets right now flown by ULA show little likeness to their progenitors, yet the names are saturated with history. The 388th flight of a rocket bearing the Delta name since 1960 was the NROL-68 mission.

The NRO’s NROL-68 mission was delayed until April so that ULA engineers could replace a hydrogen valve on the Delta 4’s upper stage that was leaking hydrogen. The NRO’s spy satellite had to be taken off the rocket for the troubleshooting, which caused a delay of approximately two months.

The engineers, according to Wentz, discovered a “really small, hard to see” piece of particulate on the valve’s sealing surface, which is used to pressurize the upper stage fuel tank. The debris was the reason the valve leaked.

Even though the Delta 4 launch vehicle is no longer in production, ULA has acquired spare parts to be able to repair or replace damaged parts on the final two rockets. Aerospace vehicles that are about to retire are frequently concerned about parts obsolescence.

Wentz stated, “We were able to secure some additional critical spares in our final order of parts, and we’ve kept those on hand.” We were able to take the valves back, rework them, and restock them as a spare part in a situation like this with the valves. Therefore, identifying the essential components, particularly those that are not utilized in either Atlas or Vulcan, has been our strategy all along.”

On another NRO mission, codenamed NROL-70, the final flight of ULA’s Delta 4-Heavy rocket is scheduled for the beginning of 2024. The Delta rocket family will retire with that launch.

Boeing created the Delta 4 rocket in the late 1990s and early 2000s, when Lockheed Martin was putting its Atlas 5 rocket into use. In 2006, Boeing and Lockheed Martin combined their rocket programs to form ULA. Up until SpaceX entered the market, ULA was the sole provider of launch services for the military’s most expensive national security satellites.

SpaceX and ULA split multibillion-dollar contracts in 2020 for a series of military satellite launches after the military approved SpaceX’s Falcon 9 rocket for national security missions in 2015. ULA will use its brand-new Vulcan Centaur rocket to fulfill its military launch commitments, whereas SpaceX will use its Falcon 9 and Falcon Heavy rockets that are already in use.

According to ULA, the Vulcan rocket is less expensive than the Atlas or Delta rockets and uses American engines instead of Russian ones that power the Atlas 5. The Delta 4-Heavy rocket uses all U.S.-made engines as well, but it costs around $300 million per flight more than the Atlas 5. The Vulcan Centaur can outlift the Delta 4-Heavy without the use of three first stage boosters in its strongest configuration.

As engineers finish their investigation into an explosive incident that occurred on the Centaur upper stage of ULA’s new Vulcan rocket during a structural test earlier this year in Alabama, it is unclear when the rocket’s first flight will take place. ULA planned to launch the first Vulcan rocket in May of this year, with the goal of certifying the new vehicle for military satellite launches by the end of 2023.

By the end of the year, it appears unlikely that the Vulcan rocket will be approved for space missions involving national security. Two successful Vulcan test launches are required for certification by the Space Force.

However, ULA has a backlog of more than 70 Vulcan rocket missions, primarily for the Pentagon and Amazon’s Kuiper broadband network, a potential rival to SpaceX’s Starlink internet constellation in the future. ULA is increasing the size of its 1.6 million square foot factory in Alabama, which was originally constructed by Boeing for the Delta 4 program before ULA moved production of its Atlas rockets there from Colorado. This move is in response to the substantial backlog. The factory is changing its focus entirely to Vulcan right now.

Wentz stated, “Obviously, for a while, we had Delta 4 and Atlas flowing through that factory.” The final assembly area for Delta 4, through which, coincidentally, we have been processing Vulcans, contains the most significant and obvious components. As a result, Vulcan final assembly will flow directly into that area, allowing us to increase our rate there.

The third and final upper stage that ULA is building for NASA’s Space Launch System rocket to transport astronauts back to the moon is the last piece of the Delta 4 program that remains at the Alabama factory. The upper stage that will power the Artemis 3 mission into space in a few years is derived from the Delta 4-Heavy design. Then, at that point, NASA will change to an all the more impressive upper stage for future SLS moon rockets.

Delays kept ULA’s launch pads silent for the first half of 2023, despite a large backlog of missions. The company’s first mission since November was a Delta 4-Heavy launch on Thursday morning from Cape Canaveral, while SpaceX’s Falcon rocket family has launched 42 flights by 2023.

One factor contributing to the sluggish start to the year was the two-month delay in the Delta 4 launch. In order for Boeing to resolve a number of technical issues with the spacecraft, the first flight of astronauts aboard Boeing’s Starliner crew capsule, which will launch on ULA’s Atlas 5 rocket, has also been postponed until at least the end of this year.

As ULA works out what it needs to do to overcome the fiery Centaur anomaly in March, which resulted in the destruction of the upper stage’s structural test article as a result of an unexpected leak of flammable hydrogen fuel, the first launch of the Vulcan rocket is also in a state of schedule uncertainty.