Дельта-IV: Американдық ракета тарихы мен тоқтатылуы

Retired expendable launch system in the Delta rocket family
the rocket

The latest evolutionary development of the Delta rocket family, Delta IV was introduced to meet the requirements of the United States Air Force's (USAF) Evolved Expendable Launch Vehicle (EELV, now National Security Space Launch (NSSL)) program. While the Delta IV retains the name of the Delta family of rockets, major changes were incorporated. Perhaps the most significant change was the switch from kerosene to liquid hydrogen fuel, with new tankage and a new engine required. The Small variant was dropped by 1999. In 2002, the Delta IV was first launched, with the RS 68 becoming the first large liquid propellant rocket engine designed in the United States since the Space Shuttle main engine (SSME) in the 1970s. The L3 Technologies Redundant Inertial Flight Control Assembly (RIFCA) guidance system originally used on the Delta IV was common to that carried on the Delta II, although the software was different because of the differences between the Delta II and Delta IV. The RIFCA featured six ring laser gyroscopes and accelerometers each, to provide a higher degree of reliability. Boeing initially intended to market Delta IV commercial launch services. However, the Delta IV entered the space launch market when global capacity was already much higher than demand. Furthermore, as an unproven design it had difficulty finding a market in commercial launches, and Delta IV launch costs are higher than comparable vehicles of the same era. In 2003, Boeing pulled the Delta IV from the commercial market, citing low demand and high costs. In 2005, Boeing stated that it sought to return the Delta IV to commercial service. As of 2009, the USAF funded Delta IV EELV engineering, integration, and infrastructure work through contracts with Boeing Launch Services (BLS). On 8 August 2008, the USAF Space and Missile Systems Center increased the "cost plus award fee" contract with BLS for US$1.656 billion to extend the period of performance through the 30 September 2008 (FY09). In addition, a US$557.1 million option was added to cover FY10. In February 2010, naturalized citizen Dongfan Chung, an engineer working with Boeing, was the first person convicted under the Economic Espionage Act of 1996. Chung passed on classified information on designs including the Delta IV rocket to China and was sentenced to 15 years. In March 2015, ULA announced plans to phase out the Delta IV Medium by 2018. With the exception of the first launch, which carried the Eutelsat W5 commercial communications satellite, all Delta IV launches have been paid for by the US government. In 2015, ULA stated that a Delta IV Heavy is sold for nearly US$400 million.

The Vulcan Centaur is planned to replace the Atlas V and Delta IV rockets. Vulcan Centaur is projected to enter service by 2023, using the BE 4 methane fueled rocket engine. The first Vulcan successfully launched on 8 January 2024. The Atlas V is expected to stay in service for a few years after Vulcan's inaugural launch, and the Delta IV Heavy was discontinued in April 2024.

The Delta IV Medium (also referred to as 'single stick') was available in four configurations: Medium, Medium+ (4,2), Medium+ (5,2), and Medium+ (5,4). The Delta IV Medium (Delta 9040) was the most basic Delta IV. It featured a single CBC and a modified Delta III second stage, with 4 meter liquid hydrogen and liquid oxygen tanks (called a Delta Cryogenic Second Stage (DCSS)) and a 4 meter payload fairing. The Delta IV Medium was capable of launching 4,200 kg to geostationary transfer orbit (GTO). From Cape Canaveral, GTO is 1804 m/s away from GEO. The mass of fairing and payload attach fittings have been subtracted from the gross performance. The Delta IV Medium+ (4,2) (Delta 9240) had the same CBC and DCSS as the Medium, but with the addition of two Orbital ATK built 1.5 m (60 in) diameter solid rocket booster Graphite Epoxy Motors (GEM 60s) strap on boosters to increase payload capacity to 6,150 kg to GTO.

The Delta IV Heavy (Delta 9250H) combines a diameter DCSS and payload fairing with two additional CBCs. These are strap on boosters which are separated earlier in the flight than the center CBC. As of 2007, a longer 5 meter diameter composite fairing was standard on the Delta IV Heavy, The trisector fairing was first used on the DSP 23 flight. The Delta IV with the extended fairing is over tall. The last launch took place on 9 April 2024, carrying the NROL 70 satellite, marking the conclusion of the Delta rocket family.

Each Delta IV consists of at least one Common Booster Core (CBC). Each CBC is powered by one Aerojet Rocketdyne RS 68 engine, which burns liquid hydrogen and liquid oxygen. On flights of the Medium, the RS 68 ran at 102% rated thrust for the first few minutes of flight, and then throttled down to 58% rated thrust before main engine cutoff. On the Heavy, the main CBC's engine throttles down to 58% rated thrust around 50 seconds after liftoff, while the strap on CBCs remain at 102%. This conserves propellant and allows the main CBC to burn after booster separation. After the strap on CBCs separate, the main CBC's engine again throttles up to 102% before throttling back down to 58% prior to main engine cutoff. The RS 68 engine is mounted to the lower thrust structure of the CBC by a four legged (quadrapod) thrust frame and enclosed in a protective composite conical thermal shield. Above the thrust structure is an aluminum isogrid (a grid pattern machined out of the inside of the tank to reduce weight) liquid hydrogen tank, followed by a composite cylinder called the centerbody, an aluminum isogrid liquid oxygen tank, and a forward skirt. Along the back of the CBC is a cable tunnel to hold electrical and signal lines, and a feedline to carry the liquid oxygen to the RS 68 from the tank. The CBC is of a constant, diameter. Two different interstages are used to mate the first stage and DCSS. A tapering interstage that narrowed down from 5 m to 4 m diameter was used to mate the 4 m DCSS to the CBC, while a cylindrical interstage is used to mate the 5 m DCSS. Both interstages were built from composites and enclosed the liquid oxygen tank, with the larger liquid hydrogen tank making up part of the vehicle's outer mold line.

Delta IV launched from either of two rocket launch complexes. Launches on the East coast of the United States used Space Launch Complex 37 (SLC 37) at the Cape Canaveral Air Force Station. On the West coast, polar orbit and high inclination launches used Vandenberg Space Force Base's Space Launch Complex 6 (SLC 6). The basic launchpad structure includes a flame trench to direct the engine plume away from the rocket, lightning protection, and propellant storage. In the case of Delta IV, the vehicle was completed on the launch pad inside a building. This Mobile Service Tower (MST) provides service access to the rocket and protection from the weather and is rolled away from the rocket on launch day. A crane at the top of the MST lifts the encapsulated payload to the vehicle and also attached the GEM 60 solid motors for Delta IV Medium launches. The MST is rolled away from the rocket several hours before launch. At Vandenberg, the launch pad also has a Mobile Assembly Shelter (MAS), which completely encloses the vehicle; at CCAFS, the vehicle is partly exposed near its bottom.

No. Date/Time(UTC) Type Serial no. Start place Payload Payload type Orbit Outcome Remarks 1 20 November 200222:39 Medium+ (4,2) 293 CCAFS, SLC 37B Eutelsat W5 Commercial communications satellite GTO First Delta IV launch. 2 2003 03 1100:59 Medium 296 CCAFS, SLC 37B USA 167 (DSCS 3 A3) Military communications satellite GTO First Delta IV Medium launch. First USAF EELV mission 3 2003 08 2923:13 Medium 301 CCAFS, SLC 37B USA 170 (DSCS 3 B6) Military communications satellite GTO 4 2004 12 2121:50 Heavy 310 CCAFS, SLC 37B DemoSat / 3CS 1 / 3CS 2 Demonstration payload GSO (planned) First Delta IV Heavy launch. Premature cutoff of CBCs. DemoSat reached incorrect orbit, 3 Corner Satellite (3CS) failed to reach orbit. 5 2006 05 2422:11 Medium+ (4,2) 315 CCAFS, SLC 37B GOES 13 (GOES N) Weather satellite GTO 6 2006 06 2803:33 Medium+ (4,2) 317 VAFB, SLC 6 USA 184 (NROL 22) Reconnaissance satellite Molniya First Delta IV launch from Vandenberg. 7 2006 11 0413:53 Medium 320 VAFB, SLC 6 USA 192 (DMSP F17) Military weather satellite SSO First Delta IV launch into a LEO/SSO, last flight of Delta IV Medium. 8 2007 11 1101:50 Heavy 329 CCAFS, SLC 37B USA 197 (DSP 23) Missile warning satellite GSO First Delta IV launch contracted by United Launch Alliance. Launch delayed due to damage to launch pad caused by a liquid oxygen leak. 9 2009 01 1802:47 Heavy 337 CCAFS, SLC 37B USA 202 (NROL 26) Reconnaissance satellite GSO 10 2009 06 2722:51 Medium+ (4,2) 342 CCAFS, SLC 37B GOES 14 (GOES O) Weather satellite GTO 11 2009 12 0601:47 Medium+ (5,4) 346 CCAFS, SLC 37B USA 211 (WGS 3) Military communications satellite GTO 13 2010 05 2803:00 Medium+ (4,2) 349 CCAFS, SLC 37B USA 213 (GPS IIF 1) Navigation Satellite MEO 14 2010 11 2122:58 15 2011 01 2021:10 Heavy 352 VAFB, SLC 6 USA 224 (NROL 49) Reconnaissance satellite LEO First Delta IV Heavy launch from Vandenberg. 17 2011 07 1606:41 Medium+ (4,2) 355 CCAFS, SLC 37B USA 232 (GPS IIF 2) Navigation Satellite MEO 18 2012 01 2000:38 Medium+ (5,4) 358 CCAFS, SLC 37B USA 233 (WGS 4) Military communications satellite GTO 19 2012 04 0323:12 Medium+ (5,2) 359 VAFB, SLC 6 USA 234 (NROL 25) Reconnaissance satellite LEO First flight in the Medium+ (5,2) version. 20 2012 06 2913:15 Heavy 360 CCAFS, SLC 37B USA 237 (NROL 15) Reconnaissance satellite GSO First flight of the RS 68A engine. Upper stage (DCSS) anomaly caused by fuel leak, payload still reached planned orbit. 22 2013 05 2500:27 Medium+ (5,4) 362 CCAFS, SLC 37B USA 243 (WGS 5) Military communications satellite GTO 23 2013 08 0800:29 Medium+ (5,4) 363 CCAFS, SLC 37B USA 244 (WGS 6) Military communications satellite GTO 24 2013 08 2818:03 Heavy 364 VAFB, SLC 6 USA 245 (NROL 65) Reconnaissance satellite LEO 25 2014 02 2101:59 Medium+ (4,2) 365 CCAFS, SLC 37B USA 248 (GPS IIF 5) Navigation Satellite MEO 26 2014 05 1700:03 Medium+ (4,2) 366 CCAFS, SLC 37B USA 251 (GPS IIF 6) Navigation Satellite MEO 27 2014 07 2823:28 Medium+ (4,2) 368 CCAFS, SLC 37B AFSPC 4 (GSSAP #1/2 and ANGELS) (USA 253/254/255) Space surveillance and technology demonstrator GEO First use of secondary payload adapter on a Delta rocket. 28 2014 12 0512:05 Heavy 369 CCAFS, SLC 37B Orion MPCV EFT 1 Uncrewed Capsule Test Flight MEO 29 2015 03 2518:36 Medium+ (4,2) 371 CCAFS, SLC 37B USA 260 (GPS IIF 9) Navigation Satellite MEO Final launch with baseline RS 68 engine. 31 2016 02 1011:40 Medium+ (5,2) 373 VAFB, SLC 6 USA 267 (NROL 45) Reconnaissance satellite LEO 32 2016 06 1117:51 Heavy 374 CCAFS, SLC 37B USA 268 (NROL 37) Reconnaissance satellite GSO 33 2016 08 1904:52 Medium+ (4,2) 375 CCAFS, SLC 37B AFSPC 6 (GSSAP #3/4) (USA 270/271) Space surveillance GEO 34 2016 12 0723:53 Medium+ (5,4) 376 CCAFS, SLC 37B USA 272 (WGS 8) Military communications satellite GTO 35 2017 03 1900:18 Medium+ (5,4) 377 CCAFS, SLC 37B USA 275 (WGS 9) Military communications satellite GTO 36 2018 01 1222:11 Medium+ (5,2) 379 VAFB, SLC 6 USA 281 (NROL 47) Reconnaissance satellite LEO Final flight of Delta IV M+ (5,2) variant. 37 2018 08 1207:31 Heavy 380 CCAFS, SLC 37B Parker Solar Probe Solar Probe Heliocentric First use of Delta IV Heavy with Star 48BV third stage (9255H). 38 2019 01 1919:10 Heavy 382 VAFB, SLC 6 USA 290 (NROL 71) Reconnaissance satellite LEO 39 2019 03 1600:26 Medium+ (5,4) 383 CCAFS, SLC 37B USA 291 (WGS 10) Military communications satellite GTO Final flight of Delta IV M+ (5,4) variant. 40 2019 08 2213:06 Medium+ (4,2) 384 CCAFS, SLC 37B USA 293 (GPS III 2) Navigation Satellite MEO Final flight of the Delta IV Medium and the Delta IV M+ (4,2) variant. 42 2021 04 2620:47 Heavy 386 VAFB, SLC 6 USA 314 (NROL 82) Reconnaissance satellite LEO 43 2022 09 2422:25 Heavy 387 VAFB, SLC 6 USA 338 (NROL 91) Reconnaissance satellite LEO Final flight of Delta IV from VSFB 44 2023 06 2209:18 Heavy 388 CCSFS, SLC 37B USA 345 (NROL 68) Reconnaissance satellite GSO 45 2024 04 0916:53 Heavy 389 CCSFS, SLC 37B USA 353 (NROL 70) Reconnaissance satellite GSO Final flight of the Delta IV rocket and of the whole Delta rocket family.

The first payload launched with a Delta IV was the Eutelsat W5 communications satellite. A Medium+ (4,2) from Cape Canaveral carried the communications satellite into geostationary transfer orbit (GTO) on 20 November 2002. Heavy Demo was the first launch of the Delta IV Heavy in December 2004 after significant delays due to bad weather. Due to cavitation in the propellant lines, sensors on all three CBCs registered depletion of propellant. The strap on CBCs and then core CBC engines shut down prematurely, even though sufficient propellant remained to continue the burn as scheduled. The second stage attempted to compensate for the shutdown and burned until it ran out of propellant. This flight was a test launch carrying a payload of:
DemoSat 6020 kg; an aluminum cylinder filled with 60 brass rods planned to be carried to GEO; however due to the sensor faults, the satellite did not reach this orbit. NanoSat 2, carried to low Earth orbit (LEO) a set of two very small satellites of 24 and 21 kg, nicknamed Sparky and Ralphie planned to orbit for one day. Given the under burn, the two most likely did not reach a stable orbit. NROL 22 was the first Delta IV launched from SLC 6 at Vandenberg Space Force Base (VSFB). It was launched aboard a Medium+ (4,2) in June 2006 carrying a classified satellite for the U. S. National Reconnaissance Office (NRO). DSP 23 was the first launch of a valuable payload aboard a Delta IV Heavy. This was also the first Delta IV launch contracted by the United Launch Alliance, a joint venture between Boeing and Lockheed Martin. The main payload was the 23rd and final Defense Support Program missile warning satellite, DSP 23. Launch from Cape Canaveral occurred on 10 November 2007. NROL 26 was the first Delta IV Heavy EELV launch for the NRO. USA 202, a classified reconnaissance satellite, lifted off 18 January 2009. NROL 32 was a Delta IV Heavy launch, carrying a satellite for NRO. The payload is speculated to be the largest satellite sent into space. After a delay from 19 October 2010, the rocket lifted off on 21 November 2010. NROL 49 lifted off from Vandenberg AFB on 20 January 2011. It was the first Delta IV Heavy mission to be launched out of Vandenberg. This mission was for the NRO and its details are classified. On 4 October 2012, a Delta IV M+ (4,2) experienced an anomaly in the upper stage's RL10B 2 engine which resulted in lower than expected thrust. While the vehicle had sufficient fuel margins to successfully place the payload, a GPS Block IIF satellite USA 239, into its targeted orbit, investigation into the glitch delayed subsequent Delta IV launches and the next Atlas V launch (AV 034) due to commonality between the engines used on both vehicles' upper stages. By December 2012, ULA had determined the cause of the anomaly to be a fuel leak (into the combustion chamber), and Delta IV launches resumed in May 2013. After two more successful launches, further investigation led to the delay of Delta flight 365 with the GPS IIF 5 satellite. Originally scheduled to launch in October 2013, the vehicle lifted off on 21 February 2014. A Delta IV Heavy launched the Orion spacecraft on an uncrewed test flight, EFT 1, on 5 December 2014. The launch was originally planned for 4 December 2014, but high winds and valve issues caused the launch to be rescheduled for 5 December 2014. On August 12, 2018, another Delta IV Heavy launched the Parker Solar Probe on a mission to explore or "touch" the outer corona of the Sun. The second GPS Block III satellite was launched with the final Delta IV Medium+ (4,2) configuration rocket on 22 August 2019.<ref name="nsf20190822/">

The final flight from Vandenberg of the Delta IV Heavy launched the NROL 91 mission in September 2022. The final flight from Cape Canaveral of the Delta IV Heavy and of the Delta rocket family took place in April 2024 carrying the NROL 70 mission.