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A Delta 2 rocket launched by United Launch Alliance took off from the California military base and disappeared on Saturday in a cloud covered, carrying a NASA research satellite in orbit and closing the book on a legacy of nearly 30 years of launches .
The 39-meter (128-foot) rocket ignited its main Aerojet Rocketdyne RS-27A kerosene engine at 06:02 PDT (9:02 am EDT, 1302 GMT) and lit four Northrop Grumman-built belts. a few seconds later, propel the Delta 2 from its launch pad to Vandenberg Air Force Base in California.
Of the 650,000 pounds of thrust, the Delta 2 rocket – in its iconic blue-green paint system – has disappeared into the low clouds, but the long-range infrared cameras have been tracking the launcher's progress since Vandenberg, a base military. run the spaceport on the central coast of California northwest of Los Angeles.
The four solid propellant propellants burned and were dropped to fall into the Pacific Ocean less than 90 seconds after takeoff, and the first phase RS-27A main engine, retracing the Saturn 1 and 1B rocket programs from the NASA from the 1960s for the last time at T + plus 4 minutes, 24 seconds.
After launching the first leg, the Delta 2's second-rate Aerojet Rocketdyne AJ10-118K engine fired for the first of four burns from Saturday's mission, then stopped at the 11-minute point of the flight. The Delta 2 flew over Antarctica, then headed north over the Indian Ocean before relighting the engine from the top floor for less than 7 seconds to make to circulate his orbit.
NASA's ICESat 2 satellite, which launched a billion-dollar mission using lasers to measure changes in the ice cap from space, was deployed from the upper floor of the rocket about 53 minutes after takeoff. A live video of the Delta 2 showed that NASA's search engine, with a capacity of 1340 kilograms, was moving away from the rocket in a black ink space.
ULA has programmed the rocket to release ICESat 2 in an orbit about 300 miles or about 474 kilometers above the Earth. Delta 2 commentator Patrick Moore confirmed that the rocket had reached an orbit very close to preflight forecasts.
ICESat 2, built by Northrop Grumman Innovation Systems, deployed its solar panel shortly after its separation from the Delta 2, commencing a 60-day commissioning schedule before commencing regular scientific ground and marine ice observations in November.
The second-stage engine of the Delta 2's AJ10 slightly adjusted its orbit to allow the separation of four CubeSats developed by university students. The CubeSats launched Saturday have for mission:
- ELFIN, or the investigation of losses and electronic fields, a space weather mission developed at UCLA with three scientific instruments in a 3U + CubeSat form factor.
- ELFIN-STAR, also from UCLA, an identical 3U + CubeSat that will allow scientists to more accurately measure the radiation environment in low Earth orbit.
- DAVE, or the experience of damping and vibration, a 1U CubeSat developed at Cal Poly with a payload to evaluate a technology of mechanical damping in microgravity
- SurfSat, a 2U CubeSat developed at the University of Central Florida to measure static charge on the surfaces of spacecraft in orbit.
Meanwhile, the upper deck of the Delta 2 fired again for the brakes to fall into orbit and return to Earth's atmosphere over the Pacific Ocean, where the rocket would break down and run out. The purpose of the desorption burn was to ensure that the mission did not add more space to the orbital routes, and the re-entry marked the official conclusion of the final Delta 2 flight.
"I'm a little sad," said Tim Dunn, NASA's launch director for the ICESat 2 mission. "I'm delighted with the success of the mission and the fact that we were able to close the chapter on Delta with tremendous success. an extremely important scientific workload.
"ICESat 2 is going to be doing some cutting-edge scientific data collection, the precision measurements it's going to be doing in space are going to be incredible," said Dunn, a 22-year veteran of the Delta 2 rocket program at Boeing and at NASA. "So being able to say that we launched this very important scientific mission in the final flight of the industry's workaholic is just a huge accomplishment for the entire team. I have a lot of personal feelings about the Delta 2, but I'm really just a tiny part of the Delta 2 team.
While the ULA Delta 4 rocket will remain in service for several more years, the Delta 2 rocket was the latest US launcher to trace its basic concept at the dawn of the space age.
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 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.
Read our previous story for the memories and thoughts of several veterans of Delta 2's launch.
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 model, incorporating various hydrogen engines and larger fuel 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 old and new members of the Delta family, using Delta 2 Thor's 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.
Delta rocket technology also entered the Japanese space program, which used Thor's first-stage licenses and AJ10 upper stage engines on Japanese launchers from the 1970s to the early 1990s, before moving to domestic designs.
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."
Here are some statistics on Saturday's launch:
- 381st launch of the Delta rocket since 1960
- 724th launch of a rocket based in Thor
- 237th Delta launch with NASA's involvement
- 155th Delta 2 rocket mission since 1989
- 14th Delta 2 to fly in the 7420 configuration
- 241st flight of an RS-27 engine
- 277th flight of an AJ10 engine
- 1,000 to 1,003rd solid rocket engines GEM-40 launched on Delta 2s
- 54th Delta 2 mission supervised by NASA
- 45th launch of the Delta 2 rocket from Vandenberg Air Force Base
"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.
Saturday's launch raised the Delta 2 record to 100 consecutive launches, a series dating back to January 17, 1997, when the workaholic suffered one of the most memorable failures of the past quarter century. A Delta 2 exploded just 13 seconds after a launch from Cape Canaveral with a GPS satellite, knocking debris off the launch pad, leaving crater parking and destroying cars outside the bunker.
No one was injured in the accident and the Delta 2 returned to flight less than four months later with an Iridium satellite launch from California.
"The Delta 2 will go down in history as one of the most successful launchers in the world and we are proud to be part of this legacy," said Eileen Drake, CEO and President of Aerojet Rocketdyne, supplier of the world's first engines. second floor.
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.
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'm looking forward to the success of the mission, "Robinson said in an interview before Saturday's launch.
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, a Florida launch 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.
Among other practices that have proven successful since the beginning of the space age, the Delta 2 continued to include manual control center control to start the RS-27A main engine. The Delta 2 countdowns did not use automatic sequencers like the new rockets.
The Delta 2 payloads were encapsulated in the nose of the rocket, above the mobile gantry of the launch pad, in a cramped clean room, while the satellites of the new US launchers are closed in their fairing.
The Delta'2 color also stood out among the world's rockets.
While the first variants of the Delta rocket were painted white, the authorities decided in the early 1970s to reduce weight by not painting the vehicle. The weight savings resulted in increased lifting capacity for the Delta rocket, and subsequent launches were made with the underlying "Delta Blue" primer, according to Collectspace.com.
"This blue-sky paint scheme," Dunn said in an interview with Spaceflight Now. "I'm going to miss this because I do not see a rocket painted in sky blue yet, but maybe there'll be one coming soon."
ICESat 2 begins Ice Monitoring Mission
ICESat 2 stands for Ice, Cloud and Land Elevation Satellite 2, a sequel to NASA's ICESat mission that measured the global ice caps from 2003 to 2009.
Featuring an enhanced laser instrument designed to provide more accurate measurements than its predecessor, ICESat 2 will extend a data series that has shown that ice was melting around the edges of Greenland and Antarctica and was found to be a major source of data. thinned in the oceans.
"What we have learned from ICES about the icecaps in Greenland and Antarctica is that they are losing ice around the coastal areas, which means they are losing ice and two, probably related to the ocean. Said Tom Wagner, a scientist with NASA's cryosphere program.
This is important because ice conditions are related to other factors that determine the Earth's climate, such as currents and temperatures in the oceans. Scientists say rising sea levels could threaten cities along the coast.
"In Antarctica and Greenland, we have about two-thirds of the Earth's freshwater," said Helen Fricker, a member of the ICSat Scientific Definition Team at the Scripps Oceanographic Institution. "If all this ice melted, we would increase the global sea level by about 180 feet (54 feet) on average, which is very significant."
Altimetry data collected by the US and French satellite series TOPEX / Poseidon and Jason show that mean sea level increased by 77 millimeters (3 inches) from 1993 to 2017.
"ICESat 2 is truly a revolutionary new tool for sea ice and sea ice research," said Tom Neumann, ICESat 2 Project Assistant Researcher at NASA's Goddard Space Flight Center.
NASA has used satellites to survey the ice for decades, but it is easier to track the ice cover than to measure the height and to estimate the thickness of the ice and ice sheets covering Antarctica and the Antarctic. Greenland.
Rather than relying on a single laser beam, as ICES did, the new mission will launch six laser beams to the Earth and measure the time it takes for the light to bounce off the surface and return to a telescope aboard the ship. space.
The ICESat 2 satellite was built by Northrop Grumman Innovation Systems and its unique instrument, the Advanced Laser Altimetry System (ATLAS), was developed at NASA's Goddard Space Flight Center.
"ATLAS essentially acts as a stopwatch," said Donya Douglas-Bradshaw, ATLAS Instrument Manager at Goddard. "The ATLAS laser fires 10,000 pulses per second with a trillion photons per shot. Whenever the laser goes off, it triggers the stopwatch. It takes about 3.3 milliseconds to beam out of the instrument, reach the surface and return to the telescope.
Only a dozen photons will reach the ICESat 2 receiver telescope, with the rest of the light diffusing into the atmosphere or space.
The laser package "has the ability to tag a single photon in a billionth of a second," Douglas-Bradshaw said in a briefing with reporters. "This accuracy allows the instrument to detect annual changes in ice elevation in the order of one-half inch (0.2 inch)."
The photon counting method is new and the development of the ATLAS laser has proven to be a challenge, delaying the launch of ICESat 2 by more than two years and adding hundreds of millions of dollars to the cost of the mission.
According to Doug McLennan, ICESat project manager at Goddard, the ground controllers plan to open a protective door covering the sensitive optics of the ATLAS instrument about a week after its launch.
After about 60 days of operation, officials hope to declare ICESat 2 ready for scientific observations.
ICESat is designed for a three-year mission, but it carries enough fuel to stay useful for more than 10 years, said McLennan.
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