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.
Supersonic speed is the speed of an object that exceeds the speed of sound (Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately 343.2 m/s. Speeds greater than five times the speed of sound (Mach 5) are often referred to as hypersonic. Flights during which only some parts of the air surrounding an object, such as the ends of rotor blades, reach supersonic speeds are called transonic. This occurs typically somewhere between Mach 0.8 and Mach 1.2.
The sound barrier or sonic barrier is the large increase in aerodynamic drag and other undesirable effects experienced by an aircraft or other object when it approaches the speed of sound. When aircraft first approached the speed of sound, these effects were seen as constituting a barrier, making faster speeds very difficult or impossible. The term sound barrier is still sometimes used today to refer to aircraft approaching supersonic flight in this high drag regime. Flying faster than sound produces a sonic boom.
A supersonic transport (SST) or a supersonic airliner is a civilian supersonic aircraft designed to transport passengers at speeds greater than the speed of sound. To date, the only SSTs to see regular service have been Concorde and the Tupolev Tu-144. The last passenger flight of the Tu-144 was in June 1978 and it was last flown in 1999 by NASA. Concorde's last commercial flight was in October 2003, with a November 26, 2003 ferry flight being its last airborne operation. Following the permanent cessation of flying by Concorde, there are no remaining SSTs in commercial service. Several companies have each proposed a supersonic business jet, which may bring supersonic transport back again.
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.
The Bell X-2 was an X-plane research aircraft built to investigate flight characteristics in the Mach 2–3 range. The X-2 was a rocket-powered, swept-wing research aircraft developed jointly in 1945 by Bell Aircraft Corporation, the United States Air Force and the National Advisory Committee for Aeronautics (NACA) to explore aerodynamic problems of supersonic flight and to expand the speed and altitude regimes obtained with the earlier X-1 series of research aircraft.
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.
Romanian Cosmonautics and Aeronautics Association, also known as ARCAspace, is an aerospace company based in Râmnicu Vâlcea, Romania. It builds rockets, high-altitude balloons, and unmanned aerial vehicles. It was founded in 1999 as a non-governmental organization in Romania by the Romanian engineer and entrepreneur Dumitru Popescu and other rocket and aeronautics enthusiasts. Since then, ARCA has launched two stratospheric rockets and four large-scale stratospheric balloons including a cluster balloon. It was awarded two governmental contracts with the Romanian government and one contract with the European Space Agency. ARCASpace is currently developing a three-stage, semi-reusable steam-powered rocket called EcoRocket and in 2022 has shifted its business model to Asteroid mining.
Scramjet programs refers to research and testing programs for the development of supersonic combustion ramjets, known as scramjets. This list provides a short overview of national and international collaborations, and civilian and military programs. The USA, Russia, India, and China (2014), have succeeded at developing scramjet technologies.
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 Mars landing is a landing of a spacecraft on the surface of Mars. Of multiple attempted Mars landings by robotic, uncrewed spacecraft, ten have had successful soft landings. There have also been studies for a possible human mission to Mars, including a landing, but none have been attempted. Soviet Union’s Mars 3, which landed in 1971, was the first successful Mars landing. As of 2022, the Soviet Union, United States, and China have conducted Mars landings successfully.
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.
SpaceX has privately funded the development of orbital launch systems that can be reused many times, similar to the reusability of aircraft. SpaceX has developed technologies over the last decade to facilitate full and rapid reuse of space launch vehicles. The project's long-term objectives include returning a launch vehicle first stage to the launch site within minutes and to return a second stage to the launch pad following orbital realignment with the launch site and atmospheric reentry in up to 24 hours. SpaceX's long term goal would have been reusability of both stages of their orbital launch vehicle, and the first stage would be designed to allow reuse a few hours after return. Development of reusable second stages for Falcon 9 was later abandoned in favor of the development of Starship, however, SpaceX has been developing reusable payload fairings for the Falcon 9.
A Mars aircraft is a vehicle capable of sustaining powered flight in the atmosphere of Mars. So far, the Mars helicopter Ingenuity is the only object to ever fly on Mars, completing 52 successful flights covering 12.168 km (7.561 mi) in 1 hour, 33 minutes and 45 seconds of flight time.
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.
The SpaceX Red Dragon was a 2011–2017 concept for using an uncrewed modified SpaceX Dragon 2 for low-cost Mars lander missions to be launched using Falcon Heavy rockets.
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 missions has been routinely landed if the rocket performance allowed it, and if SpaceX chose to recover the stage.
Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) was a NASA mission to test inflatable reentry systems. It was the first such test of an inflatable decelerator from Earth-orbital speed.
