User:Ishurio19/sandbox

Ajluni, Thomas; Everett, David; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua (2015-06-08). "OSIRIS-REx, returning the asteroid sample". 2015 IEEE Aerospace Conference. IEEE: 1–15. doi:10.1109/AERO.2015.7118988. ISBN 978-1-4799-5379-0.

Parachutes lower the troubled Apollo 13 into the Pacific Ocean, returning its crew safely back to Earth.

Parachutes in spaceflight

Parachutes and other aerodynamic decelerators have been used extensively in spaceflight and activities above the Armstrong limit, where the conditions are very similar to those found in outer space. They are often tasked with slowing down spacecraft for prolonged data gathering or landing on Earth or other celestial bodies with an atmosphere. Parachutes also serve a vital role in human spaceflight and save lives during emergencies involving astronauts. Inflatable and deployable decelerators as a replacement for heavier heat shields, for aerocapture and deorbiting satellites without the need for propellant have been proposed and are being developed for future missions.

The extreme environments in which (near-)spaceflight is conducted necessitate the development of parachute systems specifically designed to withstand those conditions. Although they have been a part of spaceflight for as long as it exists, parachutes are still considered among the most difficult technologies to develop in aerospace, largely because of the difficulties associated with predicting their behavior and that of their deployment systems. Despite this, and the rise of technologies enabling reliable deceleration and recovery without the help of parachutes, they are still favored over those technologies, because of their proven reliability, relatively low cost and risk, low weight, small storage volume requirements and wide applicability.

History

A packed parachute, its nosecone housing and its deployment device, built by Robert H. Goddard, 1935

Parachutes were invented and developed in parallel with air- and spacecraft. [Goddard? Chinese rocketeers?] Russian rocket pioneer Konstantin Tsiolkovsky first proposed the use of parachutes for returning space capsules in 1931.

The top engineers acquired by the United States Government during Operation Paperclip included parachute experts, the most prominent of them being Theodor Knacke and Helmut Heinrich. They led the development of several types of parachute that enable humans to fly missions in space safely, and aided uncrewed space exploration.

Challenges specific to space parachutes

Parachutes are considered one of the most challenging technologies to develop in spaceflight.

Spacecraft are usually significantly larger, heavier and faster objects than individual personnel, food boxes and artillery vehicles, resulting in significant challenges for the development of parachutes for spaceflight. In addition, the atmospheric conditions in which the parachutes need to be used are more extreme than . Space capsules and rockets operate in ballistic, high-g environments

Artefacts descending through an atmosphere create a wake behind them, The parachute is deployed behind that wake.

Spaceflight is a high-risk endeavor, and parachutes developed for space missions must meet stringent safety criteria while meeting maximum weight requirements. In many space missions, parachute failure is deemed a single-point failure that prematurely ends or severely compromises a mission.

Properties

Parachute systems are relatively lightweight and can be stored in spaces much smaller than their full volume, making them well-suited for use as mechanical decelerators.

Parachutes used in aerospace are packed tightly, often with the assistance of a hydraulic press.

The materials used on parachutes are selected and weighed on the basis of their strength, weight, elasticity and cost. On advanced parachutes, each part is made with a material with different properties.

During space missions, round parachutes generally experience higher loads [] crowns

The heavy objects needing to be slowed down or recovered and fast speeds reached by these objects necessitated the development of multi-parachute systems. To reduce g-forces on the vehicle and occupants, as well as loads on the parachutes, a spacecraft usually deploys a series of parachutes instead of one parachute. For initial slowdown, a spacecraft firstly deploys one or more drogue parachutes, which are smaller and made of stronger fabric. Drogues serve to stabilize the fast-moving payload through its descent in the higher parts of the atmosphere, setting up the right conditions for the main parachute(s) to be deployed at much lower altitudes. [main parachute, also include clusters for redundancy]

Preferably, parachutes are deployed when the velocity of its payload is subsonic, although this is sometimes not possible or most optimal for the mission. For those situations, drogue parachutes have been developed that can withstand supersonic speeds. With the exception of parachutes used for Mars landing missions, these are smaller []

Testing

Parachute systems for spaceflight are subjected to extensive testing regimes to ensure they perform as intended during missions. This includes deployment systems, release systems and associated landing systems, as well as the payload itself. Computer and mechanical simulations are not sufficient for determining their effectivity and performance. Fluid structure imagery has been used as a tool to predict parachute behavioiur, but even with continuing advancements in computer technologies is deemed insufficient by itself.

Deployment system tests

Mortar fire test of the X-38 emergency drogue parachute

Parachute deployment systems are as essential for successful landing or recovery of payloads and missions as the parachutes themselves. Most parachutes used in spaceflight need to be successfully deployed without any human intervention. The performance of an entirely automated parachute deployment system of a spacecraft therefore needs to be tested and evaluated thoroughly.

Deployment systems used in spaceflight that are pyrotechnics-based [must]

Vacuum chamber tests are employed to verify proper functioning of rocket and spacecraft avionics systems that signal the right altitude to deploy the parachutes.

Wind tunnel tests

The parachute for the Galileo entry probe being tested in a wind tunnel

Wind tunnel tests are able to simulate the high loads on parachutes that they will experience during an actual flight, as well as simultaneously test the deployment systems with the parachutes. Many universities and research institutes worldwide have their own wind tunnels, or access to one.

The world's largest wind tunnel is part of the Ames Research Center, and has successfully tested parachutes no more than [feet (m)] in diameter. [disadvantages] Entities sometimes perform subscale parachute wind tunnel tests to examine the properties of certain types of parachute, stitching pattern or material, because it is much more expensive to conduct full-scale tests, and sometimes because the full-scale parachutes are too big to be tested even in Ames. [size does matter] The size of a parachute affects its deployment speed, [aerodynamic properties and resistance]

Drop tests

Example of a typical drop test; a Boeing Starliner qualification article is pulled from a carrier aircraft by an extraction parachute

Drop tests can be performed by releasing test articles from carrier aircraft, balloons and crane helicopters, at varying altitudes, as high as well within the stratosphere in the case of high-altitude balloon drop tests. They are able to more realistically simulate the loads to be experienced by parachutes while on an actual mission, especially for Earth return missions. They are frequently used to test recovery systems for crewed spacecraft, and are also used to test uncrewed and interplanetary mission recovery systems.

Horizontal aerodynamic tests

A rocket sled being used for testing parachutes and experimental inflatable devices by JPL

Some parachutes, especially those designed to reduce the horizontal speed of space vehicles, are tested by being towed behind a fast-moving object, such as a large airplane. Similarly, rocket sled tests aim to reproduce high speeds and high loads on the ground, by attaching the parachute to a rocket-powered railcar. Using automobiles for such drag tests has been found by some amateurs and students to be an effective, budget-friendly way to test parachutes and their deployment systems.

Rocket launch tests

Sounding rocket tests have been employed for high-altitude and interplanetary entry missions, where there is a higher risk of failure. Parachutes, measuring equipment and weight simulators are launched into the higher parts of Earth's atmosphere, where the payload often ends up in Mars-analog conditions. Such tests are noted to be very expensive and not necessary for most missions, most of which took place in parallel with the Apollo program for NASA's first interplanetary entry missions. High-speed parachutes for uncrewed missions find significant benefit in full-scale analog simulations, especially for experimental types of parachute that failed in those tests while having proven to be successful in wind tunnel and drop tests.

Performance analysis

Any parachute used in spaceflight that returns to Earth is preferably recovered for performance analysis. For programs where parachute performance analysis is very important, high-speed cameras are used to analyse the deployment and inflation processes of parachutes, and occasional (catastrophic) failures. A point of analysis unique to space parachutes is investigating the effects of exposure to space conditions on fabric, including radiation and extreme temperature changes experienced by spacecraft carrying them.

Recovery procedures for parachutes and their payloads are thorougly rehearsed to prevent damaging or losing the parachutes. Parachutes that are recovered from the ocean are carefully lifted onto recovery vessels, rinsed with fresh water to remove salt and dirt, cleared of wildlife if needed, and hung to dry before they can be inspected. This needs to be done as quickly as possible, because the parachutes may become saturated with sea water and sink to lower parts of the ocean, or drift away. This would result in parachute performance data being lost, and the parachutes becoming environmentally hazardous.

High-altitude vehicle recovery

The film recovery capsule of the Discoverer 14 reconnaissance mission and its main parachute being recovered by helicopter

This section discusses uses of parachutes during recoveries of uncrewed objects launched to (near-)space from Earth back to Earth.

Some uncrewed objects that are launched into space or the higher parts of Earth's atmosphere

In this article, near-space is defined as the area in Earth's atmosphere between the Armstrong limit, roughly 62,000 feet (19 km) above sea level, and the boundary of outer space at 62 miles (100 km). The Armstrong limit, located in the stratosphere, is the point where the air density is low enough for water to boil at human body temperature. Artefacts descending from space and through this portion of the atmosphere can easily reach supersonic speeds without any means of propulsion and become unstable.

Suborbital recovery

Payloads and (parts of) vehicles on a suborbital trajectory use parachutes to return to Earth for recovery, inspection and/or reuse. Recovery parachutes for high-altitude balloons and sounding rockets are available to consumers off-the-shelf. They can also be sewn from scratch, as long as payload weight, size and shape are taken into account adequately.

High-altitude balloons

Recovery parachutes being attached on weather balloons while they are being prepared for flight

Parachutes for high-altitude balloon payloads do not require dedicated extraction or deployment systems. Usually, a hook attaches a balloon to the apex of the parachute, which is in turn attached to a satellite, radiosonde or novelty payload. Parachutes without a vent at the apex come with a loop of fabric for attachment. When the balloon bursts (flight termination), the parachute is usually immediately placed in a position in which it can inflate and slow down its payload. The relatively low speed of the vehicle at flight termination allows for relatively simple parachutes to be used for recovery, despite the high altitude and low density which they are exposed to.

Weather balloon payloads are often single-use, as are their parachutes. During parachute descent, they often drift away from the launch site, sometimes as far as [] . have expressed concerns about environmental pollution

Sounding rockets and amateur rocketry

An amateur rocket stage descending under parachute

Many sounding rockets and most amateur rockets are prefered to be recovered intact. Usually, hardware needs to be recovered in order to collect data on rocket performance or onboard payloads. Recovery of suborbital rockets requires the use of stronger and often multiple parachutes, because of the high, often supersonic or even hypersonic, speeds, and very high altitudes reached by such rockets. This also applies to most amateur and student rockets which do not reach extreme altitudes, because of the high speeds that are still achieved by such rockets, which often serve as a stepping stone to faster and more powerful rockets.

Wind tunnel test of a drogue parachute by the Delft Aerospace Rocket Engineering team

Deployment systems for suborbital rockets can be relatively simple as in the case of high-altitude balloons, similar to skydiving systems, or as advanced as those found in larger spacecraft.[computers decide to deploy the chutes?] Recovery systems may or may not be used on all stages of a rocket. Parachutes flown on any rocket using flammable propellant need to be protected by recovery wadding, heat-resistant recovery bags or other fireproof systems, that prevent them from burning up. Many high-power rockets employ a multistage parachute system, consisting of at least a drogue and a main parachute. Using a main parachute only is not recommended for high-power rockets, because it is very likely that it is shredded at extreme speeds or entangled with other components of the rocket at slower speeds. Otherwise, the payloads may drift too far away from the launch site to be recovered, and the drogue reduces drifting by enabling a faster initial descent in a controlled manner. The drogue is often deployed right when the rocket or upper stage reaches its apogee, which could be well above the Armstrong limit.

Instead of drogues or even mains, streamers may be used by small amateur rockets. These strips of fabric stabilize rocket parts by producing a very small amount of drag, so they fall significantly faster than under drogues or mains. These are used if cheaper components are preferred, and/or to prevent rocket parts from drifting far away from the launch site, the latter usually in combination with a main parachute.

Student rocketry clubs usually have teams dedicated to developing and producing parachutes and deployment systems. Students working on parts of rockets, including recovery systems, often write papers on their research and findings during the development process of these systems.

Orbital rocket stages

A Space Shuttle solid rocket booster splashes down under parachutes after launching STS-124.

Efforts to reduce launch costs led to the development of reusable rocket stages and strap-on boosters for orbital launch systems from the 1970s, and later on, payload fairings. Parachute recovery of orbital rocket stages has proven to be challenging.

The Space Shuttle solid rocket boosters were the largest solid-fuel rockets ever flown. Just as their parent orbiter vehicles, they were designed to be recovered. One pilot chute, one drogue parachute and three main parachutes were housed in the nosecone of each booster, and were deployed []. After recovery by vessel, the parachutes were checked for damage and repaired at the Kennedy Space Center Parachute Refurbishment Facility. The parachutes were certified to be used up to 10 times, with NASA setting the goal to 20 reuses. In the 30 years the Space Shuttle flew, all but two pairs were recovered successfully. The derivative Ares I launch vehicle, intended to succeed the Space Shuttle after its retirement, recovered its SRB first stage in a similar way. During its only flight, one of the main parachutes malfunctioned.

Ariane 5 solid rocket boosters were designed to be recovered as well, although only a few of the European workhorse rocket's missions actually featured recovery attempts of the boosters. A four-stage parachute system was used in the recovery of the solid rocket boosters, which were then retrieved by vessel, similar to the Space Shuttle SRBs. Several minutes after separation from the main stage, each SRB deployed three drogues at an altitude of around 5 km (16.400 feet) with the help of an auxiliary parachute. Then, at altitudes that have varied from 1,2 to 2,8 km (~4000-9200 feet), the drogues were released, a tertiary parachute was deployed, followed by the main parachute. Out of four documented launches from the vehicle's maiden flight in 1996 until late 2002, only two or three single SRBs were successfully recovered. Others could not be located, or were destroyed because of launch vehicle or parachute failures. The main chute of the Ariane 5 recoverable solid booster was the largest to ever be successfully used on a space mission, with a diameter of 48 meters (157,5 feet).

The China Aerospace Science and Technology Corporation (CASC) has developed parachute systems for the side boosters supporting several of its Long March launch vehicles. This followed concerns on the company's rocket parts returning to Earth in an uncontrolled manner. By making them descend under parachute, CASC aims to narrow down the potential landing area of their rocket stages, and use the parachutes to steer them to a safe location for touchdown.

Rocket Lab has been recovering a portion of their Electron rocket's first-stage boosters by parachute, akin to the Space Shuttle and Ariane 5, since the 'Return to Sender' mission in 2020. The company noted that recovering the first stage by parachute is difficult because of the heat exerted on the booster during initial descent. Likewise, SpaceX attempted to recover the first stages of their Falcon 1 and early Falcon 9 launch vehicles by parachute, but the stages burned up in the atmosphere before they could deploy their parachutes on each attempt. The company instead opted to invest in propulsive landing technologies for their booster rockets, which proved successful. The company does recover their Falcon 9 and Falcon Heavy payload fairings, priced around $6 million each, by parafoil.

Other private companies that plan or have planned to recover parts of their rockets by parachute or textile braking device include Kistler Aerospace (K-1), United Launch Alliance (Vulcan Centaur engines) and PLD Space (Miura 1 and Miura 5).

Recovery of uncrewed orbital spacecraft

Demonstration of the ExoBrake small satellite deorbiting system

Parachute descent is by far the most common recovery method for uncrewed spacecraft that for the success of their mission need to be retrieved intact on Earth. In this case, a spacecraft loses most of its speed in the early phase of reentry. The amount of parachutes used, of which kind, and when they are deployed vary per mission, and often depend on factors such as horizontal and vertical speed, size of the capsule, and risk. Uncrewed spacecraft for uncrewed missions are relatively small objects that can take relatively high loads compared to crewed spacecraft (see 'Human spaceflight'). [sample return capsules and pods used by companies producing things in space/orbit] Most of them employ drogue parachutes, while some, including the Hayabusa capsules, only employed a main parachute combined with a pilot chute.

[CORONA program] [capsules containing goods manufactured in space, see Varda]

Exo-Brake was a NASA program/system for deorbiting small spacecraft at the end of their service life.

inflatable heat shields. Development programs for these technologies include LDSD, LOFTID

Planetary entry

Further information: Atmospheric entry

Video of ESA's Huygens probe descending and landing on Titan to research its composition. Status on deployed parachutes shown upper left.

Parachutes have played an important role in the success of interplanetary missions that feature the entry into the atmosphere or landing on the surface of a celestial body. Most development for planetary entry parachutes took place from the mid-1960s to the mid-1970s, when the US and the Soviet Union extended the Space Race into Mars and Venus. Both parties sought to determine the requirements for landers to successfully touch down on Venus and Mars by sending probes to orbit the planets or enter their atmospheres.

Densities and temperatures of atmospheres, as well as gravitational pulls, vary across the Solar System's celestial bodies, and are often vastly different than Earth's. This complicates landings on other planets or moons with an atmosphere, requiring engineers to not only develop parachutes with specific performance characteristics, but also adapt their deployment systems and sequences. For instance, the conditions found in the atmosphere of a planet may require deploying parachutes early on or very late, or leave no other choice than deploying them in supersonic winds. Those conditions, as well as the properties and purposes of the spacecraft, may require the use of multiple different parachutes, or the spacecraft to be released from its canopy before touching down. In the latter case, further deceleration is performed by propulsion systems or simply the atmosphere itself.

Textile braking devices are being developed as an alternative to heavy hard-material heat shields for interplanetary missions. They can also be used to achieve aerocapture, or enter a world's orbit by using its atmosphere to slow spacecraft down.

Parachutes and inflatable decelerators for interplanetary missions are sterilized by several days of heat-treating before being mated and launched with their payloads to prevent forward contamination.

Mars

Further information: Mars atmospheric entry and Mars landing

Its relative similarities with and relatively short distance from Earth compared to other celestial bodies makes Mars a very attractive location for scientific research, and the planet deemed most suitable for being the first outside Earth to become inhabited by humans. [] makes the conditions encountered by spacecraft entering its atmosphere, and thus the necessities for a successful landing, relatively well known. Landing on Mars is known to be a challenging feat, with more than half of all attempts ending in failure. [Many challenges faced by entities ... supesonic parachute]

The very thin atmosphere of Mars does not allow for viable parachutes to be used for soft-landing all the way down, as shown by the wreckage of the Mars 2020 parachute system.

Mars' atmosphere is a hundred times less thick than Earth's. Like on the Moon, spacecraft can only soft-land there with the use of retropropulsion, but the presence of an atmosphere requires for a heat shield to be employed as well. [not enough fuel can be brought onboard] As of April 2024, all spacecraft aiming to soft-land on Mars have employed a supersonic parachute.

Weight and size restrictions are stringent for Mars and interplanetary missions, because of the limited amount of thrust launch vehicles have been able to produce. Post-Space Race Mars missions have also dealt with limited budgets. Instead, parachutes have been employed to drastically decelerate a craft in the lower atmosphere of Mars until retropropulsion can be effective. Nevertheless, payloads will still crash on Mars when only using parachutes because, even close to the ground, there is too little air resistance for the terminal velocity to be within the boundaries of a soft landing.

Parachutes used for Mars landings need to withstand very high speeds in low-pressure environments and extreme wind speeds. These supersonic parachutes need to be considerably larger and lighter than drogue parachutes used during Earth returns, increasing the risk of vehicle re-contact, self-contact, tearing and shredding upon deployment and inflation. After the properties of the Martian atmosphere were discovered, NASA tested parachutes in near-space, often Mars-analog conditions in a series of sounding rocket and high-altitude balloon drop tests.

[Although parachutes are found to be reliable, it is increasingly prefered that they are not used on future missions to Mars.] [] JPL engineers have proposed and are testing alternative means to slow down and land the Mars Sample Return lander on Mars to remove the need for parachutes. SpaceX has provided NASA with data on retropropulsion in Mars-analog conditions during its Falcon reusability program, and plans to land its Starship spacecraft on Mars using its heat shield and landing engines only. [Team Tumbleweed] have also been proposed.

Human spaceflight

An astronaut-candidate using parachute fabric to build a shelter during survival training

As of 2024, all human-rated spacecraft have used round parachutes for at least a portion of their recoveries. Most spacecraft supporting human missions have relied on parachutes for deceleration in the lower parts of the atmosphere and touchdown; some landed or have been planned to land on a runway with or without the help of deployed decelerators. Although propulsive vertical landing has also been proposed for some spacecraft, parachutes are advantaged by their proven reliability and relatively low cost, and continue to be used despite their low precision due to susceptibility to changing winds.

Astronauts and high-altitude aviators are trained to use the components of parachutes to make tents, clothing or other items useful for survival after emergency landings. Many of them have gone through extensive training for near-space emergency bailouts and subsequent freefall and parachute descent phases. Parachuting is included in many governmental and private astronaut training programs, furthermore serving to prepare astronauts for the intensity and small margins of error inherent to spaceflight, and stressful situations that might occur during their missions.

Crewed capsule parachutes

A Soyuz capsule touching down under the eye of a recovery helicopter

Parachute descent is the most frequently employed method of bringing crew and valuable cargo back to Earth safely, and has been used for all crewed capsules and recoverable cargo capsules. [reasons for this include the ability to recover the capsule on almost any surface] Extra considerations need to be made to recover crewed orbital spacecraft, because [human payloads].

A series of round parachutes have been used for recovery by every human-rated space capsule, although a glider-like parachute was proposed for the Gemini project. The Apollo capsules were the first human-rated spacecraft to use a cluster of multiple parachutes.

The Mercury, Gemini, Soyuz and Shenzhou capsules have employed a single drogue with a single main parachute. The Apollo, Orion and Boeing Starliner capsules have used a system with [pilots, drogues and mains]. The Blue Origin New Shepard and SpaceX Dragon capsules use a simplified multi-parachute deployment system with up to three drogues, which pull out up to four mains when released.

Deployment sequence

An Orion test capsule releases its drogue parachutes (one is seen upper right), after which pilot chutes (middle) extract its main parachutes (left).

After entering the thicker parts of the atmosphere, usually around an altitude of (10-5 km), the capsule deploys one or more drogue parachutes, most often by means of a mortar or mortar-deployed pilot parachute. This may be preceded by the ejection of the capsule's top cover, sometimes descending under its own parachutes to increase safety margins. Depending on the size, weight, speed and safety requirements of the capsule, the drogues remain attached to the capsule for a few seconds to a full minute. The main parachutes are then extracted by either the drogues or pilot parachutes that are fired from their own mortars after the drogues are cut away.

The main parachutes of SpaceX Crew-4 in their second stage of reefing. Note the differing rates of inflation.

To reduce shock loads and acceleration forces on astronauts and fragile cargo upon deployment, most crew capsule parachutes have their drag coefficient temporarily reduced in a process called reefing. This is usually achieved by rigging one or more lines around the skirt of the parachute that restrict the circumference of the canopy mouth. The lines are then cut by a small machine after a pre-determined amount of seconds. Reefing also helps to reduce and evenly distribute stresses on the canopies and lines, and in particular for larger parachutes, encourages even inflation. The reefing lines themselves must also be strong enough to resist the parachute's urge to open fully, as that can cause them to rupture.

During parachute descent, ground control informs astronauts on parachute deployment, the speed of descent and the status of the parachutes. The crew, unable to see what happens outside, is notified if the parachutes appear healthy (fully deployed, inflated and undamaged), and if not, what precautions to take. Upon touchdown or splashdown, the main parachute(s) is/are usually released from the capsule to prevent entanglement and inadvertent redirection of the capsule upon re-inflation, and to enable recovery of the parachutes and the capsule. Spacecraft manufacturers [must] ensure that the crew can cut away the parachutes when the parachute fails to release itself or during certain malfunctions.

Military personnel are often involved in emergency operations in human spaceflight worldwide. Pararescuemen are on standby every crewed launch from the US to ensure the astronauts can always rely on qualified rescue services when they are forced to abort the launch or mission. If needed, the rescuers arrive at the emergency landing site by parachute.

Uses of parachutes by spaceplanes

For spaceplanes, parachutes are often not necessary because the shape of these vehicles allows for them to be flown like gliders in the lower parts of the atmosphere and landed like any other airplane. Use of drag chutes is still prefered, because of the higher landing speeds of such spacecraft than is usual for aircraft.

Space Shuttle Discovery deploys its brake chute at the end of STS-119

In the later years of its service, the Space Shuttle used a 40-feet (12,2 m) diameter brake chute to help slow itself down. The use of brake chutes on Shuttle was planned from the beginning of its development in the early 1970s, but was eventually omitted to save weight. During the earlier years of the Shuttle program, Shuttles experienced high degrees of wear and tear during landings, with a few close calls. After the Challenger disaster in 1986, it was recommended by the Rogers Commission that the brake parachute system be reintroduced to the Shuttle to add extra margins of error, along with adjustments for the runways where the Shuttles landed on. Drogue parachutes were used starting from the maiden flight of Endeavour (STS-49) in 1992, and all other remaining Shuttles were modified to include parachute systems afterwards. After the door that protects the parachute system was jettisoned, the drogue parachute was extracted by a mortar-deployed pilot chute (9 feet (2,74 m) in diameter) by command of the Shuttle's pilot as soon as the Shuttle's aft wheels were comfortably on the ground. The chute was reefed for several seconds to prevent the Shuttle from bouncing off the runway, then allowed to fully open. The parachute was released just before the Shuttle slowed down sufficiently and retrieved after use. Each Space Shuttle drogue parachute could be reused up to fifteen times. A total of 86 Shuttle missions used the brake parachute system.

The Soviet Buran spaceplane was similarly equipped with three drag chutes that assisted the spacecraft during landing.

The NASA X-38, a proposed lifeboat vehicle for ISS crewmembers, would have used a parachute much in the way space capsules do. It was designed to deploy its parachute while still in the air and descend under canopy.

Near-space emergency egress

Main article: Space diving

The parachute deployment sequence of the Gemini launch escape system

Flying above 40.000 feet (12 km) became increasingly common practice during the Second World War, and many concerns on parachute behavior during high-altitude bailouts had already surfaced by then. Aircraft capable of long-duration operations above the Armstrong limit were developed not much later, proving to be crucial for surveillance capabilities during the Cold War. To address existing concerns on high-altitude emergency egress and uncover new ones, both the US and the Soviet Union undertook several development programs from the 1940s to 1960s to enable their military pilots to survive bailing out at extreme altitudes and usually supersonic horizontal speeds during emergencies. Under these programs, great benefit was found in the use of drogue parachutes for stabilizing personnel falling from high altitudes, and delaying the opening of main parachutes until thicker parts of the atmosphere are reached. During and since the Cold War, there have been numerous incidents involving high-altitude aircraft in which the crew were forced to eject, egress in or otherwise made to descend on their own in the conditions of near-space, including the 1960 U-2 incident.

Ground crew assist a Space Shuttle astronaut with his parachute pack

Similarly, to protect them from the hazards of high altitude during emergencies, Space Shuttle astronauts flying before STS-5 and after STS-51L wore a full pressure suit and a 72 lbs (32 kg) parachute pack with emergency supplies during launch and reentry. During the first four Shuttle flights, astronauts had the capability to eject from the spacecraft during a malfunction at virtually any altitude during ascent or descent. This capability was previously found in the Gemini crew capsule. After STS-4, Space Shuttle Columbia had its ejection seats deactivated, and all other Shuttles were not outfitted with crew ejection systems; because the Space Shuttle always flew with at least four crew after the testing campaign, ejection seats were considered impractical. [was met with criticism from pilots and other personnel] After the Challenger disaster, the remaining Shuttle orbiters were modified to enable emergency egress of up to eight crew when the spacecraft was in a stable position at no higher than 60.000 feet (18 km). Astronauts would leave the spacecraft by sliding down a pole they deployed from the ingress hatch to avoid recontact with the shuttle, before automatic systems would deploy their parachutes at an appropriate altitude.

[Since the [], scholars have [] if an astronaut could survive returning to Earth from space or even orbit with only a spacesuit]. Airmen Joseph Kittinger and Yevgeny Andreyev successfully demonstrated the survivability of a fall from heights above 20 km (12 miles) with suit and parachutes only, during respectively American and Soviet military development programs taking place in the 1960s. Escape pods, such as MOOSE and the paracone, were designed and proposed in the 1960s, but were later shelved or canceled.

Felix Baumgartner's stratospheric skydive in 2012 rekindled interest and enthusiasm worldwide for high-altitude parachute jumps and the associated research on its effects on people and technologies. Two years later, former Google executive Alan Eustace performed a similar feat after working with a team of scientists and engineers, motivated by a desire to find out how humans could survive falling to Earth from outer space.

Types of parachute developed for or frequently used in spaceflight

Selection of decelerators developed for extreme environments, by Goodyear

The complex and wide-compassing process of addressing the challenges of deceleration in spaceflight and near-space activities has resulted in the invention and development of many types of parachute. They vary greatly in strength, porosity, size and function, so there are parachutes fit for almost every circumstance involving an atmosphere. Some have known widespread use in areas outside of spaceflight, while others are specifically tailored to the extremes of space.

Ribbon parachutes

Ribbon parachutes are very tolerant to high speeds, making them well-suited for use in spaceflight. Their invention is attributed to Theodor Knacke [was he part of the FIST team that is accredited with its invention in the 1930s?]. The canopies of ribbon parachutes consist of dozens of rings ('ribbons') of thick, high-strength fabric roughly one or two inches (several centimeters) wide, separated by gaps approximately the same size. They are often reused, even those used in spaceflight recoveries.

Conical ribbon

SpaceX Crew-4 descending under drogues

Conical ribbon parachutes have known extensive use in aerospace. have the highest drag coefficient for high-porosity parachutes. [why?]

Conical ribbon parachutes have served as braking parachutes for high-altitude aircraft and spaceplanes, including the SR-71 Blackbird and the Space Shuttle. They have also been instrumental in the recovery systems of most space capsules, where they have been employed as drogue parachutes. A conical ribbon parachute served as the final slowing mechanism for the Galileo entry probe during its descent through Jupiter's atmosphere.

Hemisflo ribbon

Hemisflo ribbon parachutes are ribbon parachutes specifically designed to stabilize and decelerate payloads at speeds up to Mach 3. Its name is derived from []

Ringslot

The Ringslot is a derivative design to the conical ribbon, with larger and fewer rings and gaps between them. This type was also developed by Knacke, while at Wright-Patterson Air Force Base. Parachutes of this type are often made of thinner material than ribbon parachutes. In spaceflight, they have found extensive use as extraction parachutes for drop tests, braking chutes and pilot chutes.

Ringsail

Ringsail parachutes have been used on all American space capsules (here seen at the end of Gemini 9).

Another derivative of the ribbon parachute is the ringsail, invented in 1955 by Ed Ewing. It improved on the Ringslot design by increasing its drag coefficient through [the use of sails, or pockets]. Although more expensive to produce than most other parachutes, this type is renowned for its high reliability, low opening shock loads and tolerance to damage, making it the ideal round parachute for crewed Earth returns. Ringsail parachutes have been used as main parachutes for all American crewed capsule recoveries [and Shenzhou?], often in clusters of three or four. They were also deemed exceptionally suitable for supersonic deceleration, although they have fallen out of favor .

Solid cloth

Solid cloth parachutes consist of a single sheet of fabric, often divided into sections, or gores, for structural reinforcement. These are the simplest parachutes used in spaceflight. Their simplicity makes them cheap and relatively easy to produce. However, they are deemed unsuitable for high-risk and human missions, because [oscillation]. NASA's Stardust and OSIRIS-REx sample return missions used a solid cloth triconical parachute as a main parachute.

Disk-Gap-Band

The parachute of the Perseverance rover was one of many DGBs tasked with landing spacecraft on Mars.

The Disk-Gap-Band (DGB) is a round solid-cloth parachute with [a gap in the cloth between the crown and skirt fabric]. The large gap increases porosity significantly, allowing excess air to escape. The DGB design is renowned for its balance in drag and stability while being relatively cheap and simple. Invented by Clinton W. Eckstrom in the late 1960s, it was initially designed for the recovery of high-altitude meteorological research payloads, and proved to be adept to extreme speeds and low air densities. NASA performed a series of high-altitude supersonic drop and flight tests to improve on its design for the Viking missions, for which it was eventually selected. The DGB remains the prefered parachute for interplanetary atmospheric entries and has been used on all successful Mars landing missions as of 2024, as well as Huygens, and will be used on the Dragonfly mission to Titan. They remain an often-used type of parachute for high-altitude Earth recoveries, including Stardust, [] and the recovery of some Long March rocket stages.

Disksail

The Disksail parachute was developed by JPL engineers as part of the LDSD program, which sought to develop more advanced deceleration systems for the Mars 2020 mission. It combined the properties of the established DGB and Ringsail types, aiming to produce a stronger parachute. This type of parachute was retired from development after a series of dissatisfactory tests.

Cruciform

Cruciform parachutes are solid-cloth parachutes that inflate in a shape akin to a cross or a box. They were developed for military and aerospace purposes to reduce oscillation. When deployed, they experience relatively low opening shocks. In addition, they are easy and cheap to produce. Cross-shaped parachutes served as the main parachutes for the Japanese Hayabusa and Hayabusa2 asteroid sample return missions, and as drogues for the Soviet Buran spaceplane. A similar cross-shaped braking device was tested during the ExoBrake program by NASA.

Ballute

Main article: Ballute

Concept art of an inflatable heat shield

The ballute, a parachute that inflates into a balloon-like shape, is designed for high-speed decelerations in upper atmospheres. It is deemed ideal to be used as a drogue parachute in high-speed, low-density environments, and has proven to be adept to speeds with higher Mach numbers than most other parachutes designed for such purposes. They have been tested successfully at analog speeds of up to Mach 10.

The main kind of ballute is a relatively small textile bag with inlets, with which the ballute inflates itself, attached directly behind its payload or with a long cord. This is called a trailing ballute. To prevent it from violently [], [an inflatable ring,] called a burble fence, is built in around its widest point.

Other types of ballute are integrated in the entry vehicle, expanding the surface area of the vehicle when inflated, and increasing air resistance even in near-space. Applications for ballutes as heat shields and aerocapture devices are being studied.

Ram-air/Parafoil

Main article: Parafoil

The parafoil of the X-38 test vehicle is the largest of its kind ever deployed.

As the most frequently employed parachute by sports and elite military parachutists today, parafoils are often worn by astronauts and other personnel involved in spaceflight training, recovery and emergencies. Additionally, they have been employed for uncrewed payloads where steerability of the parachute is deemed beneficial or necessary for mission success.

In many of these cases, programs using these parachutes for spacecraft failed, were cancelled, or opted for the use of round parachutes instead. NASA's X-38 spaceplane would have used the world's largest parafoil for recovery. It was also to be used as the main parachute for the Genesis sample return mission. Rocket Lab proposed to recover their Electron first stages with the help of ram-air parachutes, which would have been latched on a helicopter crane while mid-air.

Successful uses of the parafoil in spaceflight include the SpaceX Falcon 9 and Falcon Heavy fairing half recovery systems, and [multiple Chinese attempts to recover rocket parts]

Rogallo wing

The rogallo wing is [hang-glider] It was proposed for the Gemini capsule's landing system, similar to the X-38.

Notable missions

The following space or near-space missions (in chronological order) are noted for having full or partial parachute malfunctions during recovery, or having made significant contributions to advancing parachute technologies.

Soyuz 1

The Soyuz spacecraft was developed by the Soviets during the Space Race, with the intention to launch cosmonauts to the Moon. Vladimir Komarov was the pilot and only occupant of the spacecraft's first flight, Soyuz 1. and impacted the ground, killing Komarov.

This accident showed [the impatience and lack of carefulness] , similar to the Apollo 1 fire on the US side. After Soyuz 1, the Soviets performed at least 70 drop tests

Genesis

Genesis was a NASA mission aimed at collecting particles from the Sun (?)

The capsule would have deployed a DGB drogue at an altitude of [33ish km] and Mach [1.4ish], and a ram-air main parachute at []. Both parachutes never deployed and the capsule crashed with a speed of [] onto []. This was the result of both redundant [] meters being installed upside down. The contents of the capsule underwent a special cleaning procedure and were largely saved from contamination.

Huygens

NASA tasked the European Space Agency (ESA) do develop Huygens. The parachute system was developed by British company Vorticity [?]. It consisted of a series of DGB parachutes to better control descent rates, as the capsule had limited battery power. As of 2024, it is the furthest parachute descent and landing of an object from Earth away from its launch site.

SpaceX Demo-2

Further information: Development of the Commercial Crew Program and SpaceX Dragon 2

In 2014, SpaceX and Boeing were selected to deliver the successors to the Space Shuttle for NASA's human space transportation efforts. Both companies opted to develop capsules, prompting a return to parachute descents for American human spacecraft. Developing the Ringsail main parachutes for Crew Dragon and Starliner, respectively, proved to be a major challenge for both companies and their supplier Airborne Systems, undergoing many parachute test failures before crucial milestones.

In the case of SpaceX, a single-out drop test, in which one of the main parachutes [and a drogue?] was intentionally disabled, failed after the other three parachutes malfunctioned [upon deployment and inflation or during later phases]. This test took place shortly after the company's successful uncrewed test flight of Crew Dragon in March 2019. Due to previous failures, SpaceX Dragon capsules have flown with four parachutes instead of the usual three since the mid-2010s. As a response, SpaceX and Airborne Systems rapidly developed the Mark 3 (Mk3) parachute, which was subjected to an intensive testing regime. Personnel performed 13[?] drop tests of these main parachutes over the course of seven days in October/November 2019. As a part of this testing regime, Mk3 parachutes were flown on another uncrewed Dragon launch in January 2020. The Mk3 parachutes have the highest strength-to-weight ratio of any subsonic parachute ever developed for aerospace.

OSIRIS-REx

OSIRIS-REx collected [grams] of samples from the near-Earth asteroid 101955 Bennu on []. Akin to Genesis, the samples were returned to Earth by means of capsule and parachute. During descent, the capsule's drogue parachute did not deploy because of electrical wiring faults. Instead, its connection to the main parachute was severed at the moment it was intended to be deployed by mortar, at an altitude of 110.000 feet (31.3 km) and a speed of Mach 1.35. [mains miscomm] Despite this malfunction, the main parachute was deployed safely at an altitude of 9,000 feet () and remained healthy until the capsule touched down on Dugway Proving Ground, Utah.

See also

• Solar sail
• Retropropulsion