Liquid hydrogen in the context of "Nuclear thermal rocket"

A filling station (also known as a gas station [US] or petrol station [UK/AU]) is a facility that sells fuel and engine lubricants for motor vehicles. It serves as a local fuel depot and retailer who receive fuel products from refineries (via regular tank truck resupplies), keep the fuels in (typically underground) storage tanks, and distribute individual product to motorist consumers at a daily varied price.

The most common fuels sold are motor fuels such as gasoline (a.k.a. petrol, often as multiple products according to different octane ratings) and diesel fuel, as well as liquified petroleum gas (LPG, i.e. autogas), compressed natural gas, compressed hydrogen, hydrogen compressed natural gas, liquid hydrogen, kerosene, alcohol fuels (like methanol, ethanol, butanol, and propanol), biofuels (like straight vegetable oil and biodiesel), or other types of alternative fuels. Fuel dispensers are used to pump fuel into the fuel tanks within vehicles, gauge the volume of fuel transferred to the vehicle, and calculate the financial cost the consumer must pay. Besides fuel pumps, another significant device found in filling stations and capable of refueling certain (compressed-air) vehicles is an air compressor. However, these are generally used to inflate car tires.

Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth of the average density of Earth, but is over 95 times more massive. Even though Saturn is almost as big as Jupiter, Saturn has less than a third of its mass. Saturn orbits the Sun at a distance of 9.59 AU (1,434 million km), with an orbital period of 29.45 years.

Saturn's interior is thought to be composed of a rocky core, surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and an outer layer of gas. Saturn has a pale yellow hue, due to ammonia crystals in its upper atmosphere. An electrical current in the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but has a magnetic moment 580 times that of Earth because of Saturn's greater size. Saturn's magnetic field strength is about a twentieth that of Jupiter. The outer atmosphere is generally bland and lacking in contrast, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 kilometres per hour (1,100 miles per hour).

Cryogenic fuels are fuels that require storage at extremely low temperatures in order to maintain them in a liquid state. These fuels are used in machinery that operates in space (e.g. rockets and satellites) where ordinary fuel cannot be used, due to the very low temperatures often encountered in space, and the absence of an environment that supports combustion (on Earth, oxygen is abundant in the atmosphere, whereas human-explorable space is a vacuum where oxygen is virtually non-existent). Cryogenic fuels most often constitute liquefied gases such as liquid hydrogen.

Some rocket engines use regenerative cooling, the practice of circulating their cryogenic fuel around the nozzles before the fuel is pumped into the combustion chamber and ignited. This arrangement was first suggested by Eugen Sänger in the 1940s. All engines in the Saturn V rocket that sent the first crewed missions to the Moon used this design element, which is still in use today for liquid-fueled engines.

Ariane 6 is a European expendable launch system developed for the European Space Agency (ESA) and French Space Agency (CNES) and manufactured by a consortium of European companies, led by the prime contractor ArianeGroup. As part of the Ariane rocket family, it is operated by Arianespace, replacing the Ariane 5. The project's primary contributors were France (55.3%), Germany (21%) and Italy (7.6%), with the remaining work distributed among ten other participating countries.

This two-stage rocket utilizes liquid hydrogen and liquid oxygen (hydrolox) engines. The first stage features an upgraded Vulcain engine from Ariane 5, while the second uses the Vinci engine, designed specifically for this rocket. The Ariane 62 variant uses two P120C solid rocket boosters, while Ariane 64 uses four. The P120C booster is shared with Europe's other launch vehicle, and is an improved version of the P80 used on the original Vega.

Rocket propellant is used as a reaction mass ejected from a rocket engine to produce thrust. The energy required can either come from the propellants themselves, as with a chemical rocket, or from an external source, as with ion engines.

The Space Shuttle external tank (ET) was the component of the Space Shuttle launch vehicle that contained the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplied the fuel and oxidizer under pressure to the three RS-25 main engines in the orbiter. The ET was jettisoned just over 10 seconds after main engine cut-off (MECO) and it re-entered the Earth's atmosphere. Unlike the Solid Rocket Boosters, external tanks were not re-used. They broke up before impact in the Indian Ocean (or Pacific Ocean in the case of direct-insertion launch trajectories), away from shipping lanes and were not recovered.

RP-1 (Rocket Propellant-1 or Refined Petroleum-1) and similar fuels like RG-1 and T-1 are highly refined kerosene formulations used as rocket fuel. Liquid-fueled rockets that use RP-1 as fuel are known as kerolox rockets. In their engines, RP-1 is atomized, mixed with liquid oxygen (LOX), and ignited to produce thrust. Developed in the 1950s, RP-1 is outwardly similar to other kerosene-based fuels like Jet A and JP-8 used in turbine engines but is manufactured to stricter standards. While RP-1 is widely used globally, the primary rocket kerosene formulations in Russia and other former Soviet countries are RG-1 and T-1, which have slightly higher densities.

Compared to other rocket fuels, RP-1 provides several advantages with a few tradeoffs. Compared to liquid hydrogen, it offers a lower specific impulse, but can be stored at ambient temperatures, has a lower explosion risk, and although its specific energy is lower, its higher density results in greater energy density. Compared to hydrazine, another liquid fuel that can be stored at ambient temperatures, RP-1 is far less toxic and carcinogenic.