Liquid oxygen , sometimes abbreviated as LOX or LOXygen , is a clear cyan liquid form of dioxygen O 2 . It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard , an application which has continued to the present.
18-475: The Advanced Cryogenic Evolved Stage ( ACES ) was a proposed liquid oxygen / liquid hydrogen upper-stage for use on a number of different launch vehicles produced by Boeing , Lockheed Martin , United Launch Alliance (ULA). During the last five years of the program, ACES was proposed for eventual use on the Vulcan space launch vehicle designed by the U.S. company United Launch Alliance. The ACES concept had
36-416: Is cryogenic with a freezing point of 54.36 K (−218.79 °C; −361.82 °F) and a boiling point of 90.19 K (−182.96 °C; −297.33 °F) at 1 bar (15 psi). Liquid oxygen has an expansion ratio of 1:861 and because of this, it is used in some commercial and military aircraft as a transportable source of breathing oxygen. Because of its cryogenic nature, liquid oxygen can cause
54-432: Is classified as an industrial gas and is widely used for industrial and medical purposes. Liquid oxygen is obtained from the oxygen found naturally in air by fractional distillation in a cryogenic air separation plant . Air forces have long recognized the strategic importance of liquid oxygen, both as an oxidizer and as a supply of gaseous oxygen for breathing in hospitals and high-altitude aircraft flights. In 1985,
72-474: The USAF started a program of building its own oxygen-generation facilities at all major consumption bases. Liquid oxygen is the most common cryogenic liquid oxidizer propellant for spacecraft rocket applications, usually in combination with liquid hydrogen , kerosene or methane . Liquid oxygen was used in the first liquid fueled rocket . The World War II V-2 missile also used liquid oxygen under
90-710: The event, the long- duration upper stage concept was never able to obtain top-line attention from any of the companies as it never won full development funding from the US government, the primary source of funding for the Delta , Atlas and Vulcan rockets. However, some aspects of changes planned for ACES, such as the larger tank-diameter, were eventually used in the Centaur V upper stage. Two Advanced Cryogenic Evolved Stage (ACES) concepts were originally developed in 2005 by both Boeing and Lockheed Martin . By 2010, ULA had inherited
108-602: The intellectual property of both proposals, and the ACES concept had evolved into a new high-performance upper stage to be used on both Atlas V and Delta IV / Delta IV Heavy launch vehicles. Now called the Advanced Common Evolved Stage , ACES was proposed to be a lower-cost, more-capable and more-flexible upper stage that would supplement, and perhaps replace, the existing ULA Centaur and Delta Cryogenic Second Stage (DCSS) upper stages. This upper stage
126-493: The materials it touches to become extremely brittle. Liquid oxygen is also a very powerful oxidizing agent: organic materials will burn rapidly and energetically in liquid oxygen. Further, if soaked in liquid oxygen , some materials such as coal briquettes, carbon black , etc., can detonate unpredictably from sources of ignition such as flames, sparks or impact from light blows. Petrochemicals , including asphalt , often exhibit this behavior. The tetraoxygen molecule (O 4 )
144-768: The name A-Stoff and Sauerstoff . In the 1950s, during the Cold War both the United States' Redstone and Atlas rockets, and the Soviet R-7 Semyorka used liquid oxygen. Later, in the 1960s and 1970s, the ascent stages of the Apollo Saturn rockets , and the Space Shuttle main engines used liquid oxygen. As of 2024, many active rockets use liquid oxygen: Attitude control system Too Many Requests If you report this error to
162-440: The nitrogen has evaporated from such a vessel, there is a risk that liquid oxygen remaining can react violently with organic material. Conversely, liquid nitrogen or liquid air can be oxygen-enriched by letting it stand in open air; atmospheric oxygen dissolves in it, while nitrogen evaporates preferentially. The surface tension of liquid oxygen at its normal pressure boiling point is 13.2 dyn/cm. In commerce, liquid oxygen
180-509: The objective to improve the on-orbit lifespan of current upper stages . In 2015, ULA announced conceptual plans to transition the Vulcan rocket to the ACES second stage, also referred to as Centaur Heavy, after 2024. Vulcan will initially launch with the Centaur V upper stage. Both Boeing and Lockheed Martin had separate but similar ACES concepts prior to the formation of the jointly-owned (50% Boeing/50% Lockheed Martin) ULA in late 2006. In
198-629: The present dozens of hours to multiple days. As of April 2015, an internal combustion engine to be used to power the IVF system on ACES was to be produced by Roush Racing . In August 2016, ULA's President and CEO Tory Bruno said both Vulcan and ACES were intended to be human rated. One potential application for ACES was stated by ULA in 2010 to be the use of the longer endurance and the greater fuel capacity as propellant depot with in-space refueling capability to retrieve derelict objects for near-space clean up and deorbit . These new approaches offer
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#1732782745233216-491: The stage. The design included producing power, maintaining stage attitude and keeping the propellant tanks autogenously pressurized . Using these fluids was designed to eliminate the need for hydrazine fuel, helium for pressurization, and nearly all batteries in the vehicle. IVF was designed by ULA to be optimal for depot operations, since only liquid hydrogen and liquid oxygen would need be transferred, and it could, if built, conceivably extend mission lifetimes from
234-471: The technical prospect of markedly reducing the costs of beyond- low Earth Orbit object capture and deorbit with the implementation of a one-up/one-down launch license regime to Earth orbits. Liquid oxygen Liquid oxygen has a clear cyan color and is strongly paramagnetic : it can be suspended between the poles of a powerful horseshoe magnet . Liquid oxygen has a density of 1.141 kg/L (1.141 g/ml), slightly denser than liquid water, and
252-567: Was expected by ULA to debut on the Vulcan launch vehicle no earlier than 2023 but in July 2015 the timeframe was clarified to not likely fly until 2024–2025. In 2018, ULA gave multiple presentations that again showed an ACES debut in 2023. In 2019 however, ULA said that while they still planned to develop ACES, they no longer had a specific date for when that would be. ACES was planned to use ULA's proprietary Integrated Vehicle Fluids (IVF) technology to significantly extend its lifetime in space. ACES
270-528: Was first predicted in 1924 by Gilbert N. Lewis , who proposed it to explain why liquid oxygen defied Curie's law . Modern computer simulations indicate that, although there are no stable O 4 molecules in liquid oxygen, O 2 molecules do tend to associate in pairs with antiparallel spins , forming transient O 4 units. Liquid nitrogen has a lower boiling point at −196 °C (77 K) than oxygen's −183 °C (90 K), and vessels containing liquid nitrogen can condense oxygen from air: when most of
288-443: Was intended to incorporate improved insulation for improved cryogenic storage and longer coast durations. In April 2015, the name of the stage was reverted to the original Advanced Cryogenic Evolved Stage name, as the new ULA Vulcan design would be the only first stage rocket intended to use ACES, beginning no earlier than 2023. In September 2020, ULA stated they were no longer actively developing ACES. As of April 2015, ACES
306-491: Was planned to include common bulkhead propellant tanks with a diameter of 5.4 m (18 ft), capable of carrying 68,000 kg (150,000 lb) of propellant. In late 2017, ULA decided to bring the 5.4 m (18 ft) diameter and advanced insulation elements of the ACES upper stage forward. Under the new plan, Vulcan's upper stage is the Centaur V , with two LH2/LOX RL10 engines and no IVF or other ACES extended- duration technology as had been planned for ACES. ACES
324-590: Was then expected to have the same tank diameter as Centaur V, but stretched (longer tank length), with the possible addition of two more RL10s and IVF. On 11 May 2018, United Launch Alliance (ULA) announced that the Aerojet Rocketdyne RL10 engine was selected for Centaur V, following a competitive procurement process. The IVF technology uses a lightweight internal combustion engine to use hydrogen and oxygen propellant boil-off (normally wasted when boil-off gases are vented to space) to operate
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