Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: uncontrolled entry, such as the entry of astronomical objects, space debris, or bolides; and controlled entry of a spacecraft capable of being navigated or following a predetermined course. Technologies and procedures allowing the controlled atmospheric entry, descent, and landing of spacecraft are collectively termed as EDL.
Aerobraking is a spaceflight maneuver that reduces the high point of an elliptical orbit (apoapsis) by flying the vehicle through the atmosphere at the low point of the orbit (periapsis). The resulting drag slows the spacecraft. Aerobraking is used when a spacecraft requires a low orbit after arriving at a body with an atmosphere, as it requires less fuel than using propulsion to slow down.
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 where as 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.
In engineering, a heat shield is a component designed to protect an object or a human operator from being burnt or overheated by dissipating, reflecting, and/or absorbing heat. The term is most often used in reference to exhaust heat management and to systems for dissipating frictional heat. Heat shields are used most commonly in automotive and aerospace.
A reaction control system (RCS) is a spacecraft system that uses thrusters to provide attitude control and translation. Alternatively, reaction wheels can be used for attitude control. 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 ballute is a parachute-like braking device optimized for use at high altitudes and supersonic velocities.
Aerocapture is an orbital transfer maneuver in which a spacecraft uses aerodynamic drag force from a single pass through a planetary atmosphere to decelerate and achieve orbit insertion.
The HL-20 Personnel Launch System was a NASA spaceplane concept for crewed orbital missions studied by NASA's Langley Research Center around 1990. It was envisaged as a lifting body re-entry vehicle similar to the Soviet BOR-4 spaceplane design. Its stated goals were to achieve low operational costs, improved flight safety, and a possibility of landing on conventional runways. No flight hardware was built.
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 hypercone is a mechanism for atmospheric reentry deceleration proposed for use by future Mars landing missions. It is an inflatable structure combining characteristics of both heat shields and parachutes.
The Boeing Starliner is a spacecraft designed to transport crew to and from the International Space Station (ISS) and other low-Earth-orbit destinations. Developed by Boeing under NASA's Commercial Crew Program (CCP), it consists of a reusable crew capsule and an expendable service module.
A number of space tethers have been deployed in space missions. Tether satellites can be used for various purposes including research into tether propulsion, tidal stabilisation and orbital plasma dynamics.
Mars atmospheric entry is the entry into the atmosphere of Mars. High velocity entry into Martian air creates a CO2-N2 plasma, as opposed to O2-N2 for Earth air. Mars entry is affected by the radiative effects of hot CO2 gas and Martian dust suspended in the air. Flight regimes for entry, descent, and landing systems include aerocapture, hypersonic, supersonic, and subsonic.
Small Payload Quick Return (SPQR) is a NASA Ames Research Center concept to return small payloads from orbit.
The Falcon 9 first-stage landing tests were a series of controlled-descent flight tests conducted by SpaceX between 2013 and 2016. Since 2017, the first stage of Falcon 9 rockets are routinely landed if the performance requirements of the launch allow.
The Low-Density Supersonic Decelerator or LDSD is a reentry vehicle designed to test techniques for atmospheric entry on Mars. The disc-shaped LDSD uses an inflatable structure called the Supersonic Inflatable Aerodynamic Decelerator (SIAD), which is essentially a donut-shaped balloon, to create atmospheric drag in order to decelerate the vehicle before deploying a large supersonic parachute. The goal of the $230 m project is to develop a reentry system capable of landing 2- to 3-ton payloads on Mars, as opposed to the 1-ton limit of the currently used systems.
Electron is a two-stage, partially reusable orbital launch vehicle developed by Rocket Lab, an American aerospace company with a wholly owned New Zealand subsidiary. Electron services the commercial small satellite launch market. It's the third most launched small-lift launch vehicle in history. Its Rutherford engines are the first electric-pump-fed engine to power an orbital-class rocket. Electron is often flown with a kickstage or Rocket Lab's Photon spacecraft. Although the rocket was designed to be expendable, Rocket Lab has recovered the first stage twice and is working towards the capability of reusing the booster. The Flight 26 (F26) booster has featured the first helicopter catch recovery attempt. Rocket Lab has, however, abandoned the idea of catching Electron.
InflateSail was a 3U CubeSat launched on PSLV C38 on 23 June 2017 into a 505 km polar Sun-synchronous orbit. It carried a 1 m long inflatable rigidizable mast, and a 10 m2 drag-deorbiting sail. Its primary aim was to demonstrate the effectiveness of drag based deorbiting from low Earth orbit (LEO). Built by Surrey Space Centre of the University of Surrey, it was one of the Technology Demonstrator CubeSats for the QB50 mission. An identical drag sail payload was planned to be included on the RemoveDEBRIS demonstrator.
Team Miles was a 6U CubeSat that was to demonstrate navigation in deep space using innovative plasma thrusters. It was also to test a software-defined radio operating in the S-band for communications from about 4 million kilometers from Earth. Team Miles was one of ten CubeSats launched with the Artemis 1 mission into a heliocentric orbit in cislunar space on the maiden flight of the Space Launch System (SLS), that took place on 16 November 2022. Team Miles was deployed but contact was not established with the spacecraft.
During the lifetime of the Space Shuttle, Rockwell International and many other organizations studied various Space Shuttle designs. These involved different ways of increasing cargo and crew capacity, as well as investigating further reusability. A large focus of these designs were related to developing new shuttle boosters and improvements to the central tank, but also looked to expand NASA's ability to launch deep space missions and build modular space stations. Many of these concepts and studies would shape the concepts and programs of the 2000s such as the Constellation, Orbital Space Plane Program, and Artemis program.
