The Delta Cryogenic Second Stage (DCSS) is a family of

cryogenic In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cr ...

rocket stages A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...

used on the

Delta III Delta III was an expendable launch vehicle made by Boeing. The vehicle was developed from the highly-successful Delta II to help meet the launch demand of larger satellites. The first Delta III launch was on August 26, 1998. Of its three flights ...

and

Delta IV Delta IV is a group of five expendable launch systems in the Delta (rocket family), Delta rocket family introduced in the early 2000s. Originally designed by Boeing's Defense, Space and Security division for the National Security Space Launch, ...

rockets, and on the

Space Launch System The Space Launch System (SLS) is an American super heavy-lift expendable launch vehicle developed by NASA. As of 2022, SLS has the highest payload capacity of any rocket in operational service, as well as the greatest liftoff thrust of any r ...

Block 1. The stage consists of a cylindrical

liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully li ...

(LH₂) tank structurally separated from an oblate spheroid

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an applica ...

(LOX) tank. The LH₂ tank cylinder carries payload launch loads, while the LOX tank and engine are suspended below within the rocket's inter-stage. The stage is powered by a single

Aerojet Rocketdyne Aerojet Rocketdyne is an American manufacturer of rocket, Hypersonic flight, hypersonic, and electric propulsive systems for space, defense, civil and commercial applications. Headquartered in Sacramento, California, the company is owned by Aeroj ...

Pratt & Whitney Pratt & Whitney is an American aerospace manufacturer with global service operations. It is a subsidiary of Raytheon Technologies. Pratt & Whitney's aircraft engines are widely used in both civil aviation (especially airlines) and military aviat ...

RL10B-2 engine, which features an extendable carbon-carbon nozzle to improve specific impulse.

Delta III

The DCSS first flew on 3 Delta IIIs, failing two out of two times. A booster failed on the maiden flight and the rocket was destroyed by range safety, causing the loss of the DCSS before ignition. On its second flight, the stage tumbled uncontrollably, inserting the payload into a useless orbit. On the third flight, the stage performed the planned burn but fell short of the target orbit due to premature propellant exhaustion. The flight was deemed a failure. An un-flown example is on display outside the

Discovery Cube Orange County The Discovery Cube Orange County, formerly known as the Discovery Science Center and the Taco Bell Discovery Science Center, is a science museum in Santa Ana, California, with more than 100 hands-on science exhibits designed to spark children's ...

Delta IV

Two different versions are flown, depending on variant. Composite interstages used to mate the first and second stages together accommodate the different configurations. For the Delta IV-M, a tapering interstage that narrows down in diameter from 5 meters to 4 meters is used on the 4-meter DCSS, while a cylindrical interstage is used on the 5-meter DCSS. Since the retirement of the Delta IV-M and Delta IV-M+ rockets, the DCSS is now used solely on the

Delta IV Heavy The Delta IV Heavy (Delta 9250H) is an Evolved Expendable Launch Vehicle, expendable heavy-lift launch vehicle, the largest type of the Delta IV family. It is the world's third highest-capacity launch vehicle in operation, behind NASA's Space L ...

in its 5-meter variation. , two missions remain before ULA retires the Delta IV Heavy.

Interim Cryogenic Propulsion Stage

The Interim Cryogenic Propulsion Stage, a minimally modified 5-meter DCSS, is used as the upper stage of the

Block 1. The ICPS for Artemis I was mated to the SLS launch stack on July 6, 2021.Rosenberg, Zach
"Delta second stage chosen as SLS interim"
''Flight International'', May 8, 2012. The ICPS will be used for the first three Artemis missions before being retired in favor of the in-development

Exploration Upper Stage The Exploration Upper Stage (EUS) is being developed as a large second stage for Block 1B and Block 2 of the Space Launch System (SLS), succeeding Block 1's Interim Cryogenic Propulsion Stage. It will be powered by four RL10C-3 engines burning ...

for Artemis IV.

References

Cryogenic Second Stage Space Launch System United Launch Alliance Rocket engines using hydrogen propellant Rocket stages Boeing spacecraft and space launch systems {{rocket-stub