Delta II

The Delta II is an American launcher. The rocket family developed by McDonnell Douglas and later manufactured by Boeing IDS is since November 26, 1990 in use. The originally planned as the last take-off flight took place on 28 September 2011, although still five missiles were in stock (no solid rocket boosters ). Even before the production of the Delta II had been set. In July 2012, NASA announced that the Delta II to reinstate and has booked three more starts, so that only two missiles are in stock with no planned mission. The solid rocket boosters are produced each version accordingly. The Delta II will remain so until at least 2016 in use, even if there is a perennial start pause between 2011 and 2014.

Development

Originally, the Space Shuttle would replace all American disposable launchers, but after the Challenger disaster, the development of the Delta rocket was resumed. The Delta II replaced the delta 6XXX rockets previously developed in haste and has faced this a slightly increased payload capacity. The Delta II has been designed to meet the payload requirements of the GPS Block II satellites. In ancient numeric naming system the Delta II, Delta 7XXX is. The Delta II has been used since its first flight so far 145 times ( September 2009). Except for GPS satellites it has also been used in the 1990s to launch communications satellites. However, these are around since the late 1990s, usually too heavy for the Delta II Until August 2009 continued launched the GPS satellites to the last copy of the GPS IIR-M series with Delta II rocket. In addition, many scientific satellites and space probes of NASA and some other satellite with Delta II rockets into space.

The levels of the Delta II

Delta rockets are disposable rockets, which means that they fly only once. They consist of the following components:

• Boosters: The boosters are made of a very light carbon fiber chassis (hence the name Graphite - Epoxy Motor dec GEM ) to reduce the empty weight and are equipped with solid propellant from HTPB ( Hydroxiterminiertes polybutadiene), aluminum, ammonium perchlorate and various additives filled. You increase thrust during the initial two minutes of flight. The standard version of the Delta II has nine GEM -40 booster, the smaller versions but only three or four. The Delta II Heavy hand, uses nine of the larger GEM -46 boosters that were taken over by the now no longer built Delta III. The GEM -40 boosters have a diameter of 101.6 cm and the GEM -46 boosters have 116.8 cm. In the Standard and Heavy Delta six booster right from the start and the remaining three are ignited in flight just before burning out the top six. For the smaller versions with three or four boosters all boosters ignite on the ground.

• Step 2: A small in relation to the first stage delta K. your pressure subsidized fuel and Oxididatortanks provide a wiederzündbares Aerojet engine with hypergolischem fuel. If the flight goes into low-Earth orbit, this stage ignites long time, then switched off and fly without drive with the satellite in an elliptical parking orbit almost half way around the earth. Then she fires at apogee of the parking orbit for the second time ( shorter), and brings itself and the satellite in a nearly circular orbit at this altitude. Then she sits from the satellite. Finally, she moves away. Ignites from the satellite and after a further half earth's orbit for the third time This ignition against the flight direction one hand, serves to bring the second stage in an elliptical orbit with the lowest possible perigee to let burn up on the stage soon, on the other hand, all of the fuel will be consumed, so that the stage can not explode by the fuel residues. If the flight is in a high earth orbit or an escape path to another planet, the second stage ignites long, turns off, and flies with the satellite without drive almost halfway around the earth. Then she lights for the second time ( shorter ) until the scheduled time for this flight speed is reached. Now it is the third stage of the payload should be sitting in exactly the predetermined spatial orientation. The second stage includes the control system of the Delta II, an inertial navigation system and the flight control computer.

• Step 3: If an optional solid rocket motor from ATK Thiokol. It provides the majority of the change in velocity to exit the parking orbit, the payload may thus achieve higher Earth orbit or flight paths. Thereafter, the third stage is separated. The stage is spin stabilized and has no control systems to rate or change in position. The stage will be hosted by the second stage prior to exposure.

• Payload fairing: It consists either of a thin metal or composite material to the payload during the flight through the atmosphere to protect.

The members of the family of launchers Delta II and designation system

The individual members of the family of launchers Delta II are characterized by a four -digit number:

• The first digit: 7 denotes the 7000 series of the Delta. This series has an extra - Extended Long Tank Thor first stage with an RS- 27A engine, with a longer exhaust nozzle as the RS -27 engine of the Delta 6000 series. The extended nozzle ensures a higher expansion and a higher thrust at high altitude. GEM -40 booster larger than the castor -4A and 4B- booster of the delta -6000 series. Your composite shell is also lighter than the steel shell of the Castor booster.

• The second digit: indicates the number of boosters. Normally, with nine boosters ignite six when lifting and, after a three minute flight time ( when the first six already burned out ). On versions with only three or four boosters all boosters ignite at liftoff.

• The third digit: a 2 denotes the second stage Delta K with a Aerojet AJ10 engine. The engine is wiederzündbar.

• The fourth digit: Represents the third stage. 0 means no third stage exists, 5 stands for the PAM - D stage ( Payload Assist Module ) with a Star -48 solid engine and 6 stands for a Star 37 solid engine. The Star -37 motor is smaller and weaker than the Star -48 engine and was only for the start of particularly light space probes ( and a satellite used ), since the failure of the heavily designed for maximum cost reduction " Faster - Better - Cheaper " concept no longer be built.

• H: behind the four digit code, if it is a Delta II Heavy. The Delta II Heavy used instead of the GEM -40 boosters larger GEM -46 booster. They increase the take-off weight tremendously, but the payload simultaneously raise only slightly. The Delta Heavy is more expensive than a standard Delta II and only then is used as the payload for the normal Delta II something is too hard, but a larger rocket type not yet economically worthwhile. There are heavy versions to date (July 2009 ) with only nine boosters, the version numbers are 7925H and 7920H.

Examples: A Delta 7925 has the Thor XLT first stage RS- 27A engine, nine GEM -40 booster, and the PAM as a third stage. A Delta 7320 is a small version with three boosters and without 3rd stage.

Three payload fairings are currently available. Originally there was a smaller and another very large payload fairing.

• The smallest diameter of 2.44 m (8 foot ) has the same diameter as the Delta and is no longer used. With it, the Delta II rocket had a continuous constant diameter. For it was -8 appended to the name.

• The next larger payload fairing has a diameter of 2.9 m ( 9.5 feet). It consists of aluminum. As standard payload fairing it is most commonly used. For it is either -9.5 hung on the name or omitted the appendix.

• Then there are three payload fairings with 3.05 m diameter (10 feet). Two of these consist of a composite material. Depending on the payload it is available as standard and long-wheelbase version. For them, -10C is hung in the short version and 10L in the long version of the name. Instead of the two different lengths of payload fairings used the Delta II first one adopted by the Delta 6XXX 10-foot payload fairing made ​​of metal. This is no longer used nowadays. For it was just -10 appended to the name. Each version of the delta -II can be provided with each of the three available payload fairings.

For double -offs, there are two different lengths of double launchers inside which a satellite has space, while the other sits on it. The dual starting device is always in the interior of a three -meter payload fairing.

An example for a full description: Delta 7925H - 9.5

Delta II 7920-10

Delta II 7320 -10C

Delta II 7420 -10C

Delta II - 7925

Delta II 7920 -10C

Delta II - 7925

Delta II 7925 -10L

Delta II 7920H -10C

Delta II 7925H

Launch pads

Bring Delta II rocket, the payloads into orbits with inclinations between 28 ° and 57 °, launched in Cape Canaveral, from Launch Complex 17, which has two launch pads, 17A and 17B. However, only the grid 17B was suitable for the Delta II Heavy. Delta II rockets with payloads had to achieve ° inclination orbits between 56 ° to 104, took off from Space Launch Complex 2W ( SLC -2W ) Vandenberg Air Force Base in California.

Some known payloads of the Delta II

• DFS 3 Copernicus in 1992
• Mars Global Surveyor in 1996
• Mars Pathfinder in 1996
• Mars Climate Orbiter in 1998
• Mars Odyssey in 2001
• Mars Exploration Rovers ( Spirit and Opportunity ) in 2003
• MESSENGER in 2004
• Deep Impact in 2005
• STEREO A and B in 2006
• U.S. 193 in 2006
• Phoenix in 2007
• GLAST in 2008
• Kepler in 2009
• GRAIL in 2011

Start list of the Delta II ( incomplete)

As of October 28, 2011

Planned start

As of January 17, 2014

¹ The payloads are listed as they were above the other or side by side under accommodated (in rare cases ) in the payload fairing. The top payload first, then the second highest, etc.

² NOT necessarily the target orbit of the payload - but the path on which the payload was suspended from the upper stage.