Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.
A resistojet is a method of spacecraft propulsion that provides thrust by heating a, typically non-reactive, fluid. Heating is usually achieved by sending electricity through a resistor consisting of a hot incandescent filament, with the expanded gas expelled through a conventional nozzle.
Delta-v, symbolized as ∆v and pronounced delta-vee, as used in spacecraft flight dynamics, is a measure of the impulse per unit of spacecraft mass that is needed to perform a maneuver such as launching from or landing on a planet or moon, or an in-space orbital maneuver. It is a scalar that has the units of speed. As used in this context, it is not the same as the physical change in velocity of the vehicle.
The Vostok was a type of spacecraft built by the Soviet Union. The first human spaceflight was accomplished with Vostok 1 on April 12, 1961, by Soviet cosmonaut Yuri Gagarin.
The Voskhod was a spacecraft built by the Soviet Union's space program for human spaceflight as part of the Voskhod programme. It was a development of and a follow-on to the Vostok spacecraft. Voskhod 1 was used for a three-man flight whereas Voskhod 2 had a crew of two. They consisted of a spherical descent module, which housed the cosmonauts, and instruments, and a conical equipment module, which contained propellant and the engine system. Voskhod was superseded by the Soyuz spacecraft in 1967.
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft. For spacecraft far from Earth an orbital maneuver is called a deep-space maneuver (DSM).
A reaction control system (RCS) is a spacecraft system that uses thrusters and reaction control wheels to provide attitude control, and sometimes propulsion. Use of diverted engine thrust to provide stable attitude control of a short-or-vertical takeoff and landing aircraft below conventional winged flight speeds, such as with the Harrier "jump jet", may also be referred to as a reaction control system.
The Orbit Attitude and Maneuvering System (OAMS) was a reaction control system used in Earth orbit by the Project Gemini spacecraft. It provided both automatic and manual rotation and translation by means of 16 vernier thrusters using hypergolic propellants.
The pressure-fed engine is a class of rocket engine designs. A separate gas supply, usually helium, pressurizes the propellant tanks to force fuel and oxidizer to the combustion chamber. To maintain adequate flow, the tank pressures must exceed the combustion chamber pressure.
Lunar escape systems (LESS) were a series of emergency vehicles designed for never-flown long-duration Apollo missions. Because these missions were even more hypothetical than the planned cancelled Apollo missions, the designs were never constructed. This concept was an outgrowth of the Lunar Flying Vehicle designed by Bell Aerospace.
The Space Shuttle orbiter is the spaceplane component of the Space Shuttle, a partially reusable orbital spacecraft system that was part of the discontinued Space Shuttle program. Operated from 1977 to 2011 by NASA, the U.S. space agency, this vehicle could carry astronauts and payloads into low Earth orbit, perform in-space operations, then re-enter the atmosphere and land as a glider, returning its crew and any on-board payload to the Earth.
A gravity turn or zero-lift turn is a maneuver used in launching a spacecraft into, or descending from, an orbit around a celestial body such as a planet or a moon. It is a trajectory optimization that uses gravity to steer the vehicle onto its desired trajectory. It offers two main advantages over a trajectory controlled solely through the vehicle's own thrust. First, the thrust is not used to change the spacecraft's direction, so more of it is used to accelerate the vehicle into orbit. Second, and more importantly, during the initial ascent phase the vehicle can maintain low or even zero angle of attack. This minimizes transverse aerodynamic stress on the launch vehicle, allowing for a lighter launch vehicle.
A cold gas thruster is a type of rocket engine which uses the expansion of a pressurized gas to generate thrust. As opposed to traditional rocket engines, a cold gas thruster does not house any combustion and therefore has lower thrust and efficiency compared to conventional monopropellant and bipropellant rocket engines. Cold gas thrusters have been referred to as the "simplest manifestation of a rocket engine" because their design consists only of a fuel tank, a regulating valve, a propelling nozzle, and the little required plumbing. They are the cheapest, simplest, and most reliable propulsion systems available for orbital maintenance, maneuvering and attitude control.
The SpaceX Draco is a hypergolic liquid rocket engine designed and built by SpaceX for use in their space capsules. Two engine types have been built to date: Draco and SuperDraco.
The Modular Common Spacecraft Bus (MCSB) is a fast-development, low-cost, general purpose spacecraft platform. Its modular design is intended to reduce the cost, complexity, and lead time on missions by providing a reliable, well-characterized system that can carry a variety of payloads. According to NASA, "the spacecraft is roughly one tenth the price of a conventional uncrewed mission and could be used to land on the Moon, orbit Earth, or rendezvous with near-Earth objects."
The Space Shuttle Orbital Maneuvering System (OMS) is a system of hypergolic liquid-propellant rocket engines used on the Space Shuttle. Designed and manufactured in the United States by Aerojet, the system allowed the orbiter to perform various orbital maneuvers according to requirements of each mission profile: orbital injection after main engine cutoff, orbital corrections during flight, and the final deorbit burn for reentry. Rarely the OMS were actually ignited part-way into the Shuttle's main ascent for a few minutes to aid acceleration to orbital insertion. This occurred on STS-51-F, STS-124, STS-128 and STS-135.
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
The KTDU-80 (Russian: Корректирующе-Тормозная Двигательная Установка, КТДУ) is the latest of a family of integrated propulsion system that KB KhIMMASH has implemented for the Soyuz since the Soyuz-T. It integrates main propulsion, RCS and attitude control in a single system pressure fed from a common dual string redundant pressurized propellant system. The common propellant is UDMH and N2O4 and the main propulsion unit, is the S5.80 main engine. It generates 2.95 kN (660 lbf) of thrust with a chamber pressure of 880 kPa (128 psi) and a nozzle expansion of 153.8 that enables it to achieve a specific impulse of 302 s (2.96 km/s). It is rated for 30 starts with a total firing time of 890 seconds. The integrated system without the pressurization or tanks weighs 310 kg (680 lb); it is 1.2 m (47 in) long with a diameter of 2.1 m (83 in).
Thruster is a propulsive device used by spacecraft for station keeping, altitude control, in the reaction control system, or long-duration, low-thrust acceleration. A vernier engine or gimbal engine is a particular case used on launch vehicles where a secondary rocket or other high thrust device is used to control the attitude of the rocket while the primary thrust engine is fixed to the rocket and supplies the principal amount of thrust.
The LR-101 is a fixed thrust, single start vernier thruster developed by Rocketdyne in the mid-to-late fifties and used in the Atlas, Thor and Delta launch vehicles until 1990.
