Interplanetary spaceflight or interplanetary travel is the crewed or uncrewed travel between stars and planets, usually within a single planetary system. In practice, spaceflights of this type are confined to travel between the planets of the Solar System. Uncrewed space probes have flown to all the observed planets in the Solar System as well as to dwarf planets Pluto and Ceres, and several asteroids. Orbiters and landers return more information than fly-by missions. Crewed flights have landed on the Moon and have been planned, from time to time, for Mars, Venus and Mercury. While many scientists appreciate the knowledge value that uncrewed flights provide, the value of crewed missions is more controversial. Science fiction writers propose a number of benefits, including the mining of asteroids, access to solar power, and room for colonization in the event of an Earth catastrophe.
A rocket 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 from propellant carried within the vehicle; therefore a rocket can fly in the vacuum of space. Rockets work more efficiently in a vacuum and incur a loss of thrust due to the opposing pressure of the atmosphere.
A single-stage-to-orbit (SSTO) vehicle reaches orbit from the surface of a body using only propellants and fluids and without expending tanks, engines, or other major hardware. The term usually, but not exclusively, refers to reusable vehicles. To date, no Earth-launched SSTO launch vehicles have ever been flown; orbital launches from Earth have been performed by either fully or partially expendable multi-stage rockets.
A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants (fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder; The inception of gunpowder rockets in warfare can be credited to ancient Chinese ingenuity, and in the 13th century, the Mongols played a pivotal role in facilitating their westward adoption.
Payload is the object or the entity which is being carried by an aircraft or launch vehicle. Sometimes payload also refers to the carrying capacity of an aircraft or launch vehicle, usually measured in terms of weight. Depending on the nature of the flight or mission, the payload of a vehicle may include cargo, passengers, flight crew, munitions, scientific instruments or experiments, or other equipment. Extra fuel, when optionally carried, is also considered part of the payload.
A scramjet is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forcefully before combustion, but whereas a ramjet decelerates the air to subsonic velocities before combustion using shock cones, a scramjet has no shock cone and slows the airflow using shockwaves produced by its ignition source in place of a shock cone. This allows the scramjet to operate efficiently at extremely high speeds.
A propellant is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the engine that expels the propellant is called a reaction engine. Although technically a propellant is the reaction mass used to create thrust, the term "propellant" is often used to describe a substance which contains both the reaction mass and the fuel that holds the energy used to accelerate the reaction mass. For example, the term "propellant" is often used in chemical rocket design to describe a combined fuel/propellant, although the propellants should not be confused with the fuel that is used by an engine to produce the energy that expels the propellant. Even though the byproducts of substances used as fuel are also often used as a reaction mass to create the thrust, such as with a chemical rocket engine, propellant and fuel are two distinct concepts.
In aerospace engineering, the propellant mass fraction is the portion of a vehicle's mass which does not reach the destination, usually used as a measure of the vehicle's performance. In other words, the propellant mass fraction is the ratio between the propellant mass and the initial mass of the vehicle. In a spacecraft, the destination is usually an orbit, while for aircraft it is their landing location. A higher mass fraction represents less weight in a design. Another related measure is the payload fraction, which is the fraction of initial weight that is payload. It can be applied to a vehicle, a stage of a vehicle or to a rocket propulsion system.
A multistage rocket or step rocket is a launch vehicle that uses two or more rocket stages, each of which contains its own engines and propellant. A tandem or serial stage is mounted on top of another stage; a parallel stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or attached next to each other. Two-stage rockets are quite common, but rockets with as many as five separate stages have been successfully launched.
The Saturn IB(also known as the uprated Saturn I) was an American launch vehicle commissioned by the National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage, with the S-IVB. The S-IB first stage also increased the S-I baseline's thrust from 1,500,000 pounds-force (6,700,000 N) to 1,600,000 pounds-force (7,100,000 N) and propellant load by 3.1%. This increased the Saturn I's low Earth orbit payload capability from 20,000 pounds (9,100 kg) to 46,000 pounds (21,000 kg), enough for early flight tests of a half-fueled Apollo command and service module (CSM) or a fully fueled Apollo Lunar Module (LM), before the larger Saturn V needed for lunar flight was ready.
A space vehicle is the combination of a spacecraft and its launch vehicle which carries it into space. The earliest space vehicles were expendable launch systems, using a single or multistage rocket to carry a relatively small spacecraft in proportion to the total vehicle size and mass. An early exception to this, the Space Shuttle, consisted of a reusable orbital vehicle carrying crew and payload, supported by an expendable external propellant tank and two reusable solid-fuel booster rockets.
Thrust-to-weight ratio is a dimensionless ratio of thrust to weight of a rocket, jet engine, propeller engine, or a vehicle propelled by such an engine that is an indicator of the performance of the engine or vehicle.
The classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity can thereby move due to the conservation of momentum. It is credited to Konstantin Tsiolkovsky, who independently derived it and published it in 1903, although it had been independently derived and published by William Moore in 1810, and later published in a separate book in 1813. Robert Goddard also developed it independently in 1912, and Hermann Oberth derived it independently about 1920.
In aerospace engineering, mass ratio is a measure of the efficiency of a rocket. It describes how much more massive the vehicle is with propellant than without; that is, the ratio of the rocket's wet mass to its dry mass. A more efficient rocket design requires less propellant to achieve a given goal, and would therefore have a lower mass ratio; however, for any given efficiency a higher mass ratio typically permits the vehicle to achieve higher delta-v.
The Saturn II was a series of American expendable launch vehicles, studied by North American Aviation under a NASA contract in 1966, derived from the Saturn V rocket used for the Apollo lunar program. The intent of the study was to eliminate production of the Saturn IB, and create a lower-cost heavy launch vehicle based on Saturn V hardware. North American studied three versions with the S-IC first stage removed: the INT-17, a two-stage vehicle with a low Earth orbit payload capability of 47,000 pounds (21,000 kg); the INT-18, which added Titan UA1204 or UA1207 strap-on solid rocket boosters, with payloads ranging from 47,000 pounds (21,000 kg) to 146,400 pounds (66,400 kg); and the INT-19, using solid boosters derived from the Minuteman missile first stage.
An aeroshell is a rigid heat-shielded shell that helps decelerate and protects a spacecraft vehicle from pressure, heat, and possible debris created by drag during atmospheric entry. Its main components consist of a heat shield and a back shell. The heat shield absorbs heat caused by air compression in front of the spacecraft during its atmospheric entry. The back shell carries the load being delivered, along with important components such as a parachute, rocket engines, and monitoring electronics like an inertial measurement unit that monitors the orientation of the shell during parachute-slowed descent.
A reaction engine is an engine or motor that produces thrust by expelling reaction mass, in accordance with Newton's third law of motion. This law of motion is commonly paraphrased as: "For every action force there is an equal, but opposite, reaction force."
Mass fraction may refer to:
Tronador is a series of Argentine rockets, including the Tronador I and Tronador II vehicles, to develop a liquid-propellant rocket expendable launch system called ISCUL.
Vehicle weight is a measurement of wheeled motor vehicles; either an actual measured weight of the vehicle under defined conditions or a gross weight rating for its weight carrying capacity.
