Ракета отыны ретінде азот тетраоксидінің қолданылуы

Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex USSR/Russian rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium mixture with nitrogen dioxide. Its molar mass is 92.011 g/mol. Dinitrogen tetroxide is a powerful oxidizer that is hypergolic (spontaneously reacts) upon contact with various forms of hydrazine, which has made the pair a common bipropellant for rockets.

Nitrogen tetroxide is used as an oxidizing agent in one of the most important rocket propellant systems because it can be stored as a liquid at room temperature. Pedro Paulet, a Peruvian polymath, reported in 1927 that he had experimented in the 1890s with a rocket engine that used spring loaded nozzles that periodically introduced vaporized nitrogen tetroxide and a petroleum benzine to a spark plug for ignition, with the engine putting out 300 pulsating explosions per minute. Paulet would go on to visit the German rocket association Verein für Raumschiffahrt (VfR) and on March 15, 1928, Valier applauded Paulet's liquid propelled rocket design in the VfR publication Die Rakete, saying the engine had "amazing power". Paulet would soon be approached by Nazi Germany to help develop rocket technology, though he refused to assist and never shared the formula for his propellant. In early 1944, research on the usability of dinitrogen tetroxide as an oxidizing agent for rocket fuel was conducted by German scientists, although the Germans only used it to a very limited extent as an additive for S Stoff (fuming nitric acid). It became the storable oxidizer of choice for many rockets in both the United States and USSR by the late 1950s. It is a hypergolic propellant in combination with a hydrazine based rocket fuel. One of the earliest uses of this combination was on the Titan family of rockets used originally as ICBMs and then as launch vehicles for many spacecraft. Used on the U. S. Gemini and Apollo spacecraft and also on the Space Shuttle, it continues to be used as station keeping propellant on most geo stationary satellites, and many deep space probes. It is also the primary oxidizer for Russia's Proton rocket. When used as a propellant, dinitrogen tetroxide is usually referred to simply as nitrogen tetroxide and the abbreviation NTO is extensively used. Additionally, NTO is often used with the addition of a small percentage of nitric oxide, which inhibits stress corrosion cracking of titanium alloys, and in this form, propellant grade NTO is referred to as mixed oxides of nitrogen (MON). Most spacecraft now use MON instead of NTO; for example, the Space Shuttle reaction control system used MON3 (NTO containing 3% NO by weight).

On 24 July 1975, NTO poisoning affected three U. S. astronauts on the final descent to Earth after the Apollo Soyuz Test Project flight. This was due to a switch accidentally left in the wrong position, which allowed the attitude control thrusters to fire after the cabin fresh air intake was opened, allowing NTO fumes to enter the cabin. One crew member lost consciousness during descent. Upon landing, the crew was hospitalized for five days for chemical induced pneumonia and edema.

The tendency of N2O4 to reversibly break into NO2 has led to research into its use in advanced power generation systems as a so called dissociating gas. "Cool" dinitrogen tetroxide is compressed and heated, causing it to dissociate into nitrogen dioxide at half the molecular weight. This hot nitrogen dioxide is expanded through a turbine, cooling it and lowering the pressure, and then cooled further in a heat sink, causing it to recombine into nitrogen tetroxide at the original molecular weight. It is then much easier to compress to start the entire cycle again. Such dissociative gas Brayton cycles have the potential to considerably increase efficiencies of power conversion equipment. The high molecular weight and smaller volumetric expansion ratio of nitrogen dioxide compared to steam allows the turbines to be more compact. N2O4 was the main component of the "nitrin" working fluid in the decommissioned Pamir 630D portable nuclear reactor which operated from 1985 to 1987.