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When the first Delta 2 rocket took off on Valentine's Day in 1989, ideas like smartphone navigation and robot driving on Mars were science fiction. More than 150 launches over the past 30 years have helped change all that.
The Delta 2 era is expected to end Saturday with the launch of NASA's ICESat 2 Earth Observation Satellite from Vandenberg Air Force Base in California, ending a program designed during the Cold War and going back to the space age. .
The takeoff is scheduled for 5:46 am local time (8:46 am EDT, 12:46 pm GMT) on Saturday, and the launch window continues until 8:20 pm PDT (11:20 am EDT; 1520 GMT).
Hundreds of members of the Delta team and retirees from United Launch Alliance, NASA and other companies involved in rocket history gathered Thursday night for a Santa barbecue party Maria, bringing together a group that has participated in the launch of several Delta 2 flights since 1989.
Many engineers in recent weeks have counted the number of Delta 2 missions they have worked on. Many NASA and NASA launch service program executives, who oversee the agency's robotic satellite launches, can trace their Delta 2 careers in the 1980s and 1990s.
Chuck Dovale, Deputy Director of the Launch Services Program, said the Delta 177 mission in 1984 was one of his first missions to Hangar AE, which houses the Mission Director's Center in Cape Canaveral. This predates the Delta 2 program, which has perpetuated the tradition of number theft sequentially.
"It was back when (NASA) still had the launch basics," said Dovale. "So it was not necessary to be a satellite of NASA. We still had rockets and the launch pad. We launched for the Navy. We have launched many trade missions. One of my first was NATO 3D – Delta 177.
"Unfortunately, shortly thereafter, there was a weather satellite on a delta in May 86 that failed," said Dovale. "It was a bad year for launches. I probably never learned it in less time than after this failure. "
The loss of a GOES meteorological satellite in May 1986 occurred less than four months after the l '. Challenger crash, which anchored the Space Shuttle fleet as the US government began to move more military launches to NASA's space plane. As a result of the Challenger accident, the Air Force funded the development of an upgraded version of the Delta rocket, now Delta 2, for military satellites, such as GPS navigation devices. , can move in space.
Dovale later became the launch director of NASA, managing many Delta 2 flights carrying the agency's scientific probes before taking a leadership position in the Launch Services program.
Tim Dunn will serve as NASA's launch director for Saturday's mission, 22 years after joining the Delta 2 program with Boeing, which merged its launcher division with Lockheed Martin in 2006 to form ULA. The builders of the Delta rocket family have changed names through several corporate mergers and acquisitions, starting with the Douglas Aircraft Company, and then McDonnell Douglas and Boeing before ULA.
The first launch of a Delta rocket took place in May 1960, starting a derivative of the Thor intermediate-range ballistic missile capable of putting a satellite into orbit. Engineers extended the original 8-foot (2.4-meter) original stage of the Thor several times, increasing the propulsion capacity of the Delta, while adding a new multi-stage engine and sliding belt thrusters to carry payloads heavier in space.
The Delta rocket line has been on the eve of retirement several times, perhaps especially in the 1980s, when the US government attempted to transfer all its satellite launches to the Space Shuttle. This policy changed as a result of the Challenger accident in 1986, resulting in the creation of Delta 2 and the restart of the Delta production line.
"Delta has such a rich history going back to 1960," Dunn told Spaceflight Now. "If you're talking to the program with real gray beards, it was probably on the brink of death at least three, maybe four times, when everyone thought it was the last pitch ever, and that's it. they were all he continued to have a new life.
"For this version of Delta, we are certain that it will not fly after ICESat 2," he said.
After serving as a GPS satellite analyzer and Titan 4 launch controller in the air force, Dunn joined the Delta 2 program by supporting dozens of missions as an engineer. guide of the day of launching. One of his first missions on the Delta 2 rocket was the launch of Mars Pathfinder in December 1996, which allowed NASA to visit the red planet.
"One of our first missions was the Mars Pathfinder mission," Dunn said. "It was the very small vehicle we sent to Mars in the fall of 1996". This one was really satisfying for me as it was a mission in extra-cool space with NASA, our client at the time … We were sending something to crawl to the surface of Mars.
Before launching the mission, Hot Wheels produced a miniature version of Mars Pathfinder's Sojourner robot.
"My son was just two years old, so I could tell him something with toys," Dunn said. "So, Pathfinder stands out."
Dunn joined NASA in 2000, joining the ranks to be entrusted with his first mission as Director of Launch in 2011, the final flight of a Delta 2 since Cape Canaveral.
"Just like Tim, I grew up with Delta 2," said Dovale. "It has always been my favorite. It's sad to see him go. It's good to see ICESat 2 launched successfully, but it's going to be bittersweet. "
Some engineers go even further with Delta, which has launched 380 times in its many variants.
An 82-year-old avionics advisor, who participated in the readiness review at launch on Thursday, made his first mission Delta – Delta 33 – in 1965, said Dunn.
The more powerful Delta 4 rocket will continue to fly for ULA, named Delta in the 2020s, but is also expected to retire between the early and mid-2020s.
The Delta 4 is a new design incorporating different hydrogen engines and larger propellant tanks than the Delta 2. Boeing, which ran the Delta program in the late 1990s, designed the Delta 3 rocket as a bridge between the Delta family, using Delta 2's Thor-based first stage and the Delta 4's new upper stage.
The Delta 2, which sometimes took off two or three times a month in the 1990s and 2000s, was replaced by a fleet of larger launchers. ULA then focused on the Atlas 5 and Delta 4 boosters, and the SpaceX Falcon 9 rocket now ships a large number of custom payload types for the Delta 2.
Many commercial and military missions, once served by satellites sized to fly on the mid-lift Delta 2 launcher, are now being accomplished by smaller spacecraft, taking advantage of the trend towards miniaturization of the technology. At the other end of the mass spectrum, many commercial communication satellites exceeded the capabilities of the Delta 2 in the 1990s and 2000s.
In its configuration with nine solid propellant propellants, a Delta 2 could charge more than 6,600 pounds (3,000 kilograms) of payload in an orbit 833 kilometers above the Earth.
Delta 2 rockets successfully launched 48 satellites for the US Air Force Global Positioning System from 1989 to 2009, a two-decade period during which the satellite network was part of the daily lives of billions of people in the world.
"Supporting the Air Force for all these years is a special memory with GPS," Dunn said. "From 1989, when the GPS 2-1 was first launched in the 1990s, the GPS moved from this military system that only the military used essentially to a common daily utility. It was really fun to support and support the constellation that everyone was starting to use. In 2018, and when you talk to young children about GPS, they can not imagine life without GPS, on your phone, on your watch, in your car.
The GPS fleet includes more than 30 satellites and more than half of the GPS satellites currently in orbit have been launched by Delta 2s. The network is vital for civil navigation, families traveling by car, hikers, airliners landing in low visibility.
"Every person who turns on their phone to get around, this GPS constellation is really amazing," said Scott Messer, director of ULA's Delta 2 program. "The constellation itself is amazing, but the fact that Delta 2 had the effect of launching that and making it possible was certainly a pleasure."
Messer's first mission with the Delta 2 program was Delta 230
"The Delta 2 vehicle has probably touched the lives of everyone in America in the technology it has made possible over the past 30 years," said Messer. "It has been a very important part of the history of space."
Other Delta 2s have sent NASA's first three rovers Mars – Sojourner, Spirit and Opportunity – to the Red Planet, as well as the MESSENGER mission to orbit Mercury, the Dawn mission to the asteroid, the telescope Space Spitzer, Kepler Observatory. meteorological satellites and dozens of commercial and military communications spacecraft.
From Vandenberg, Delta 2 rockets transported most of Iridium's first-generation low-Earth-orbit satellite voice and data relay fleet between 1200 and 2002. These satellites are now being replaced by a new Iridium fleet launched on SpaceX Falcon 9 rockets.
The Globalstar satellite network, also designed for mobile communications, has been deployed by a series of Delta 2 rockets launched from Cape Canaveral.
Of the 154 Delta 2 missions launched to date, 44 were from Vandenberg, a spaceport on the central California coast, north-west of Los Angeles, conducive to launching polar orbits, favored by many spacecraft satellites. earth observation.
"An even more exciting number for me is the number of successful launches we've had on Delta 2, we've had 99 consecutive successful launches, and ICESat 2 will be number 100," said Messer.
The series of successful missions dates back to 1997, when a Delta 2 rocket suffered one of the most memorable launch accidents of the past quarter century, blowing up 13 seconds after Cape Canaveral took off.
The Delta 2, which will launch ICESat 2, will be powered by a kerosene-burning core RS-27A Aerojet Rocketdyne engine, four Northrop Grumman-supplied rocket boosters and a second AJ10-118K engine, also Aerojet Rocketdyne The mission's target ICESat 2: A roughly circular polar orbit about 500 kilometers above the Earth.
"The Delta 2 will go down in history as one of the world's most successful launchers and we are proud to be part of this legacy," said Eileen Drake, CEO and President of Aerojet Rocketdyne.
The main RS-27A engine, which generates 200,000 pounds of sea level thrust, is a descendant of the H-1 engine used on the main stages of NASA's Saturn 1 and Saturn 1B rockets, the predecessors of the Saturn rocket 5 moon. Apollo Program. In addition to a main thrust chamber, the RS-27A features two vernier engines for roll control during flight.
The second-floor AJ-118K engine has its origins in the 1950s ballistic missile programs, according to Aerojet Rocketdyne. It's a combination of Aerozine 50, a fuel cocktail made by mixing hydrazine and dissymmetric dimethylhydrazine, and a nitrogen tetroxide-based oxidizer to provide 9,850 lbs. thrust in altitude.
"This final launch of Delta 2 will mark the 241st flight of the RS-27 and the 277th flight of the AJ10; all offer 100% reliability to ensure mission success for our customers, "Drake said in a statement. "This outstanding record represents the hard work and dedication of generations of Aerojet Rocketdyne employees over the past several decades."
Elizabeth Jones, head of Aerojet Rocketdyne's RS-27 and AJ10 programs, said Friday that the Delta 2 engines have undergone several improvements over the decades, adding power and performance to the crew. The two types of engines will not fly after Saturday's mission, but a similar engine to the AJ10 will continue to be launched with the NASA Orion crew capsule.
"We said at some of our meetings, who will be the first to crack? Will someone tear up? It's a moving time, there's a long legacy we can be proud of, "said Jones.
"I will miss the job, I will miss people," said Latanjia Robinson, chief engineer of A10jet Rocketdyne. "I'll miss out on the launch sites to take care of the different tasks before the launch and the launches themselves. But it will be rewarding. I look forward to a successful mission.
"I'm starting to be moved by thinking about it, but it will be a bit bitter-sweet to see the end of such a great program that has had such a big impact on our society as a whole," Robinson said in an interview.
Robinson counts Delta 228 – a Delta 2 launch of Florida in 1995 with the Koreasat 1 communications satellite – as the first mission in the launch control center. It will be back in control at Saturday's countdown, following AJ10 engine temperatures and pressures before take-off.
Jones said his first launch of Delta 2 in the control center was Delta 305, launched in Florida in 2004 with a payload GPS navigation.
The Delta 2 could fly with three, four or nine solid rocket engines built by Northrop Grumman Innovation Systems, formerly known as Orbital ATK. Over the course of the program's history, more than 1,000 solid engines have been launched with Delta 2 rockets.
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Follow Stephen Clark on Twitter: @ StephenClark1.
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