Delta IV
The family of launchers Delta IV presents the latest versions of the starting since 1960 Delta rockets dar. Delta IV was developed as part of the EELV program ( Evolved Expendable Launch Vehicles ) of the USAF to develop modular rocket types that both the light Delta II, the moderate Atlas II and Atlas III as well as the heavy Titan IV should replace. The Delta IV family was developed by Boeing and is now in direct competition with the also incurred under the EELV program Atlas V rocket family of Lockheed Martin.
Unlike Delta II and III, all on the Delta I built up as a first stage (although this was modified continuously ), an entirely new first stage was designed for Delta IV, which is driven by an also newly developed rocket engine RS -68 of Rocketdyne. The first stage was called the Common Booster Core and forms the basis for all versions of the Delta IV, depending on the number of CBCs can be made between the versions Delta IV Medium and Delta IV Heavy.
Currently, five different versions of the Boeing Delta IV series available, four of which are in the medium - class and one is the Heavy variant. The first launch of a medium - variant was held on 20 November 2002 and the first start of the Heavy version on 21 December 2004.
- 4.1 technology
- 4.2 Payload Fairings 4.2.1 Double -start capability
Technology
Delta IV is a two-stage rocket, the two stages of high-energy fuel mixture of liquid oxygen and liquid hydrogen ( LOX/LH2 ) are operated. She is currently also the only rocket around the world that can stand out with a LOX/LH2-Haupttriebwerk in the first stage without the help of solid boosters of the earth (see, unlike the European Ariane 5 and Japanese H -II). Calculations show even that the first stage of the Delta IV theoretically without the help of the second stage can carry a small payload into orbit and thus could serve as a single-stage carrier ( this has in practice no sense, because it is uneconomical ).
Main stage
The first stage of the rocket, the Common Booster Core ( CBC), in contrast to all previous versions of Delta is a completely new development. It forms the basis of all Delta -IV versions, with the heavy heavy- variant uses the same three CBCs (more on this in the Delta IV -Heavy- section). The CBC is 40.9 m high with a diameter of 4.88 m and weighs about 24.5 tons without fuel. The stage below contains a friction stir welded tank for liquid hydrogen, above a friction stir welded tank for liquid oxygen and is driven by an RS -68 engine.
The used in the first stage of the Delta IV rocket RS -68 engine was developed by the U.S. company Rocketdyne. RS -68 was created with the aim to simplify the engine compared to the space shuttle main engine SSME significantly in order to make it more affordable can. This has been largely dispensed with, the efficiency of the engine. For example, effective production methods were used, and it was an ablative cooling ( See also: ablative heat shield ) of the exhaust nozzle used. By these measures the mass of the engine increased, the production costs decreased considerable. The engine has a mass of 6696 kg, has at the start of a specific impulse of 3580 Ns / kg or 365 s (in vacuum 4022 Ns / kg or 410 s ) and developed when lifting a thrust of 2891 kN ( 3312 kN in vacuum ), which is the strongest LOX/LH2-Triebwerk world. The performance of the engine can be adjusted from a minimum of 60% to a maximum of 102% of the nominal thrust. An RS -68 will cost about 14 million U.S. dollars. When the engine is the first new development of a large rocket engine in the U.S. since the SSME over 20 years ago.
In order to increase the payload capacity of the first stage can be enhanced by several GEM -60 solid rocket boosters, which represent an enlarged version of the GEM -46 boosters of the Delta III. The booster comprising a casing made of composite materials and a diameter of 1.55 m will be built by Alliant Techsystems and include swiveling thrusters that help the RS -68 main engine in controlling the missile. On 29 June 2012 for the first time launched a rocket with the increased thrust RS- 68A engines in their CBCs.
Advanced level
The second stage of the Delta IV was largely taken from the Delta III and is driven by an engine RL -10B -2 Pratt & Whitney. The engine generates a thrust of 110 kN, has a specific impulse of 4532 Ns / kg or 462 s and is a variant of the RL -10 engine, the Centaur upper stage, which also has an extendable exhaust nozzle. This step makes it easier to integrate into the rocket, but still offers after the staging and subsequent extension of the nozzle to the full length increased performance. The existing carbon fiber composites exhaust nozzle is manufactured SEP in France. The stage is different from the Centaur also by the fact that their tanks maintain stability even without pressurization, which is not the case with the Centaur. The stage is virtually identical for all versions of the missile family and differs only in diameter and the fuel capacity. So there is the smaller step with continuous 4 m in diameter, and about 20,410 kg Treibstoffzuladung 850 s total burn time and the larger step, the oxygen tank is prolonged by about 0.5 m and a hydrogen tank having a diameter of 5 m. This variant of the stage can hold 27,200 kg of fuel, allowing a total burn time of about 1125 s
Payload fairings
The Delta IV Medium and Delta IV Medium (4,2) use a fairing with 4 meters in diameter, made of composite materials. It is 11.75 m high, 6.93 m of which has the full outer diameter of 4 m. The cylindrical part has 3.75 m internal diameter. The remaining part of the length occupies the cone-shaped, rounded at the top tip.
The Delta IV Medium (5,2) and Delta IV Medium (5,4 ) use a fairing with 5 meters in diameter, made of composite materials. It is 14.34 meters high, of which 8.32 m has the full outer diameter of 5 m. The cylindrical part has 4.57 m internal diameter. The remaining part of the length occupies the slightly curved inwards above rounded tip.
Double -start capability
The Delta IV is from 2018 also can perform starts with two main payloads simultaneously.
Infrastructure
The starting complexes for the Delta IV are present both on the Cape Canaveral AFS and at the Vandenberg AFB. In Cape Canaveral, the rocket is launched into orbit with inclination angles of 42 ° to 110 ° from the ramp LC -37B, which have already been used in the 1960s for unmanned Saturn I and Saturn IB launches. In the rocket from Vandenberg Launch Complex SLC -6 takes off, which was formerly built for launch of the MOL program, and should later serve as a launching pad for the Space Shuttle. From Vandenberg of orbital inclinations of 151 ° to 210 ° are available. The assembly and preparation of the rocket carried horizontally in an assembly hall (HIF - Horizontal Integration Facility ), before the start she is using the FPE (Fixed Pad Erector ) erected vertically on the launch pad. The assembly of the solid rocket boosters and the payload carried vertically on the launch pad. The missile is manufactured in Alabama and transported by ship Delta Mariner to the starting point.
On 25 June 2003 it was announced that Boeing had insight into confidential files of its competitor Lockheed Martin and knew its pricing. As a result, Boeing were withdrawn in July 2003, seven of 20 already ordered flights and Lockheed Martin awarded. Also accounted for the privilege to bring the only company from Vandenberg from satellites in orbit.
Coated Delta -IV -Small versions
Originally a small- series was planned, with the RS -68 engine and as a second step, the delta K of the Delta II rocket should use a CBC first stage. In addition to this first version, it should also be a second Small version with an additional Star - 48B third stage. This should be 2200 kg can bring to escape velocity according to the plans in the geostationary transfer orbit or 1860 kg. Both versions were canceled.
Delta IV Medium
A Delta IV medium series consists of a CBC first stage with the RS -68 engine and the second stage with the RL- 10B2 engine. Various payload fairings are used depending on the payload to be transported. Moreover, small solid rocket boosters (GEM -60) can be attached to the first stage of the rocket to increase the payload capacity. Due to the variations of the payload fairings and the number of solid rocket boosters caused a total of four different medium versions, with the help of loads of different mass and diameter can be launched flexible.
The individual versions of the medium - range are:
- Delta IV medium - has a payload fairing diameter of 4 m and no solid rocket boosters. The payload capacity is 8120 kg for a low orbit and 4210 kg for a Geotransfer orbit. The first launch took place on 11 March 2003.
- Delta IV Medium (4,2) - differs from the medium - basic version only by two additional GEM -60 booster, bringing the payload capacity for a low orbit rises to 10,430 kg and for a Geotransfer orbit at 5845 kg. The first launch of this version was held on 20 November 2002 and was also the first launch of a Delta IV at all.
- Delta IV Medium (5,2) - differs from the Delta Medium (4,2 ) by a payload fairing of 5 m diameter and a slightly larger fuel capacity of the second stage. Due to the heavier payload fairing, the payload capacity decreases compared to the Medium (4,2) to 7980 kg for a low orbit and 4640 kg for a Geotransfer orbit. So far (as of December 2009), this version of the missile is not used.
- Delta IV Medium (5.4 ) - the strongest version of the media number, and differs from the medium (5,2) by two further GEM -60- booster, so that the number of booster increases to four. The payload capacity is 11,425 kg for a low orbit and 6565 kg for a Geotransfer orbit. This version was launched for the first time on December 5, 2009 with the military communications satellite WGS- third
Delta IV Heavy
To start heavy spy satellites and to replace expensive titanium IV launcher, should a heavy transport variant of the Delta IV, known as the Delta IV Heavy, will be developed. This should be relatively inexpensive to manufacture and operate, and have high reliability in order to start up to 1 billion -dollar military satellites.
Technology
Delta IV Heavy consists of three CBCs wherein CBC is the central stage and the other two are arranged on the right and left thereof. The second stage is powered by an RL 10B2 engine and carrying a payload fairing with 5 m diameter. At the start of all three CBCs are fired simultaneously, the rocket ascends very slowly and about 10 s needs to pass the launch tower. After some time, the RS -68 engine of the central level will be adjusted down to 60 % of thrust, while the engines of the two additional CBCs continue to work with 102% of the thrust. This ensures that the fuel of the additional CBCs is faster to end so that they are empty after about 4 minutes of flight and can be dropped. After the payload is further accelerated by the central level until it too is completely burned out. Subsequently, the second stage does the acceleration to move the payload to the target orbit.
The Delta IV Heavy is 71 meters high and weighs 717 tonnes at the start. Her three bundled CBCs develop a total thrust of 8847 kN. The payload capacity is given 23,000 kg for a low orbit and 13,130 kg for a Geotransfer orbit. With the increased thrust RS- 68A engines payload capacity in the GTO continues to rise to 14,560 kg The Delta IV Heavy with the old RS -68 brings about 10,000 kg a lunar transfer orbit and about 8000 kg on a Mars transfer orbit. This Delta IV Heavy is the new RS- 68A engines currently strongest standing in use U.S. missile ( the moon rocket Saturn V was much heavier and stronger, but it is no longer manufactured) and exceeds their performance both at the latest European rocket Ariane 5 ECA and the Russian heavy load carrier proton-M ( the future Angara -A5 to 24,500 kg, higher payload capacity for the low orbit as Delta IV heavy with (RS -68) have ). From its main competitor, the planned Heavy version of the Atlas V rocket, the payload capacity of the Delta IV Heavy is slightly outbid: Atlas V Heavy can carry up to 25,000 kilograms in a low orbit and to 13.6 thousand kilograms in a Geotransfer orbit.
Payload fairings
The composite payload fairing is just 19.1 m high, of which 13.07 m has the full outer diameter of 5 m. The cylindrical part has 4.57 m internal diameter. The remaining part of the length occupies the slightly curved inwards above rounded tip.
The metal fairing is 19.81 m high, of which 13.76 m has the full outer diameter of 5 m. The cylindrical part has 4.57 m internal diameter. The remaining part of the length takes the top one in the form of a rounded top double cone. This payload fairing splits when it is dropped, lengthwise into three parts.
Double -start capability
As already mentioned above is the Delta IV can perform from 2018 also launches simultaneously with two main payloads.
First flight
The initial launch of the Delta IV Heavy was held on 21 December 2004, 21:50 UTC held in Cape Canaveral, with only a 6 -ton satellite dummy and two built by students ' test satellite " of 15 kg each were on board. Since Boeing could not find a paying customer for the first start, the USAF bought the first test launch of the rocket for a sum that was about 140-170 million dollars. However, the start did not go as planned: both the two boosters and the central level off their engines off a little early, so that the payload has been exposed in a low orbit. The reason the formation of bubbles was identified by cavitation in the oxygen tank afterwards, so that the fuel sensors prematurely reported that the tanks are empty. Nevertheless, Boeing looks at the first start as a success, since all phases of flight were successfully tested.
View
Since the satellite launch market is developing very slowly, all currently to be started commercial payloads will be covered by the existing Delta IV -Medium- and Heavy variants. In particular, the Delta IV Heavy is so strong that it had no commercial payloads can be found on the market currently, so that it can be used only for starting of heavy spy satellites. Currently, the Boeing Delta IV offers not on the commercial market to, but focuses on the more lucrative government contracts. In 2005, Boeing and Lockheed Martin have formed the joint venture United Launch Alliance ( ULA ). ULA will be active for boot orders of the U.S. government. ULA in this area is virtually a monopoly, as all calls to the U.S. government include satellite transports the condition that the delivering company must be a company in the USA. Other providers in the U.S. do not have missiles that can carry large payloads so. As a result, the starting prices for the next order have almost doubled, and the cost of the EELV program has increased by 14.44 billion U.S. dollars.
But should start manned lunar and Mars missions in the next decade, as announced by former U.S. President George W. Bush in January 2004, but very heavy launchers are needed so that Boeing already on plans for new Delta IV Heavy versions works. By the attachment of GEM -60 solid boosters and other modifications to the existing delta IV Heavy rocket a payload capacity of about 50,000 kg for a low orbit can be achieved. By bundling several CBCs the payload capacity can be increased even further, but major revisions of the launch facilities and infrastructure are necessary for it. A future Delta IV Heavy with a total of seven bundled CBCs could bring up to 100,000 kg to low Earth orbit. Since NASA has chosen a derived from the Space Shuttle and the Saturn V carrier system ( SLS rocket family) for their plans manned Moon and Mars flights, the chances of realizing greater Delta -IV variants are low.
Start list
As of February 21, 2014
Planned start
State of the list: March 16, 2014