Aerospike engine

Last updated

XRS-2200 linear aerospike engine for the X-33 program being tested at the Stennis Space Center Twin Linear Aerospike XRS-2200 Engine PLW edit.jpg
XRS-2200 linear aerospike engine for the X-33 program being tested at the Stennis Space Center

The aerospike engine is a type of rocket engine that maintains its aerodynamic efficiency across a wide range of altitudes. [1] It belongs to the class of altitude compensating nozzle engines. [2] Aerospike engines were proposed for many single-stage-to-orbit (SSTO) designs. They were a contender for the Space Shuttle main engine. However, as of 2023 no such engine was in commercial production, although some large-scale aerospikes were in testing phases. [3]

Contents

The term aerospike was originally used for a truncated plug nozzle with a rough conical taper and some gas injection, forming an "air spike" to help make up for the absence of the plug tail. However, a full-length plug nozzle may also be called an aerospike.

Principles

The purpose of any engine bell is to direct the exhaust of a rocket engine in one direction, generating thrust in the opposite direction. The exhaust, a high-temperature mix of gases, has an effectively random momentum distribution (i.e., the exhaust pushes in any direction it can). If the exhaust is allowed to escape in this form, only a small part of the flow will be moving in the correct direction and thus contribute to forward thrust. The bell redirects exhaust moving in the wrong direction so that it generates thrust in the correct direction. Ambient air pressure also imparts a small pressure against the exhaust, helping to keep it moving in the "right" direction as it exits the engine. As the vehicle travels upward through the atmosphere, ambient air pressure is reduced. This causes the thrust-generating exhaust to begin to expand outside the edge of the bell. Since this exhaust begins traveling in the "wrong" direction (i.e., outward from the main exhaust plume), the efficiency of the engine is reduced as the rocket travels because this escaping exhaust is no longer contributing to the thrust of the engine. An aerospike rocket engine seeks to eliminate this loss of efficiency. [1]

Comparison between the design of a bell-nozzle rocket (left) and an aerospike rocket (right) Aerospikeprinciplediagram.svg
Comparison between the design of a bell-nozzle rocket (left) and an aerospike rocket (right)

Instead of firing the exhaust out of a small hole in the middle of a bell, an aerospike engine avoids this random distribution by firing along the outside edge of a wedge-shaped protrusion, the "spike", which serves the same function as a traditional engine bell. The spike forms one side of a "virtual" bell, with the other side being formed by the outside air. [1]

The idea behind the aerospike design is that at low altitude the ambient pressure compresses the exhaust against the spike. Exhaust recirculation in the base zone of the spike can raise the pressure in that zone to nearly ambient. Since the pressure in front of the vehicle is ambient, this means that the exhaust at the base of the spike nearly balances out with the drag experienced by the vehicle. It gives no overall thrust, but this part of the nozzle also doesn't lose thrust by forming a partial vacuum. The thrust at the base part of the nozzle can be ignored at low altitude. [1]

As the vehicle climbs to higher altitudes, the air pressure holding the exhaust against the spike decreases, as does the drag in front of the vehicle. The recirculation zone at the base of the spike maintains the pressure in that zone to a fraction of 1 bar, higher than the near-vacuum in front of the vehicle, thus giving extra thrust as altitude increases. This effectively behaves like an "altitude compensator" in that the size of the bell automatically compensates as air pressure falls. [1]

The disadvantages of aerospikes seem to be extra weight for the spike. Furthermore, the larger cooled area can reduce performance below theoretical levels by reducing the pressure against the nozzle. Aerospikes work relatively poorly between Mach 1–3, where the airflow around the vehicle has reduced the pressure, thus reducing the thrust. [4]

Variations

Several versions of the design exist, differentiated by their shapes. In the toroidal aerospike the spike is bowl-shaped with the exhaust exiting in a ring around the outer rim. In theory this requires an infinitely long spike for best efficiency, but by blowing a small amount of gas out of the center of a shorter truncated spike (like base bleed in an artillery shell), something similar can be achieved.

In the linear aerospike the spike consists of a tapered wedge-shaped plate, with exhaust exiting on either side at the "thick" end. This design has the advantage of being stackable, allowing several smaller engines to be placed in a row to make one larger engine while augmenting steering performance with the use of individual engine throttle control.

Performance

Rocketdyne conducted a lengthy series of tests in the 1960s on various designs. Later models of these engines were based on their highly reliable J-2 engine machinery and provided the same sort of thrust levels as the conventional engines they were based on; 200,000 lbf (890 kN) in the J-2T-200k, and 250,000 lbf (1.1 MN) in the J-2T-250k (the T refers to the toroidal combustion chamber). Thirty years later their work was revived for use in NASA's X-33 project. In this case the slightly upgraded J-2S engine machinery was used with a linear spike, creating the XRS-2200 . After more development and considerable testing, this project was cancelled when the X-33's composite fuel tanks repeatedly failed.

CSULB aerospike engine Aerospike close-up.jpg
CSULB aerospike engine

Three XRS-2200 engines were built during the X-33 program and underwent testing at NASA's Stennis Space Center. The single-engine tests were a success, but the program was halted before the testing for the two-engine setup could be completed. The XRS-2200 produces 204,420 lbf (909,300 N) thrust with an Isp of 339 seconds at sea level, and 266,230 lbf (1,184,300 N) thrust with an Isp of 436.5 seconds in a vacuum.

The RS-2200 Linear Aerospike Engine [5] was derived from the XRS-2200. The RS-2200 was to power the VentureStar single-stage-to-orbit vehicle. In the latest design, seven RS-2200s producing 542,000 pounds-force (2,410 kN) each would boost the VentureStar into low Earth orbit. The development on the RS-2200 was formally halted in early 2001 when the X-33 program did not receive Space Launch Initiative funding. Lockheed Martin chose to not continue the VentureStar program without any funding support from NASA. An engine of this type is on outdoor display on the grounds of the NASA Marshall Space Flight Center in Huntsville Alabama.

NASA's Toroidal aerospike nozzle Non-truncated toroidal aerospike nozzle.jpg
NASA's Toroidal aerospike nozzle

The cancellation of the Lockheed Martin X-33 by the federal government in 2001 decreased funding availability, but aerospike engines remain an area of active research. For example, a milestone was achieved when a joint academic/industry team from California State University, Long Beach (CSULB) and Garvey Spacecraft Corporation successfully conducted a flight test of a liquid-propellant powered aerospike engine in the Mojave Desert on September 20, 2003. CSULB students had developed their Prospector 2 (P-2) rocket using a 1,000 lbf (4.4 kN) LOX/ethanol aerospike engine. This work on aerospike engines continues; Prospector-10, a ten-chamber aerospike engine, was test-fired June 25, 2008. [6]

Nozzle performance comparison of bell and aerospike nozzle Nozzle performance comparison.svg
Nozzle performance comparison of bell and aerospike nozzle

Further progress came in March 2004 when two successful tests sponsored by the NASA Dryden Flight Research Center using high-power rockets manufactured by Blacksky Corporation, based in Carlsbad, California. The aerospike nozzles and solid rocket motors were developed and built by the rocket motor division of Cesaroni Technology Incorporated, north of Toronto, Ontario. The two rockets were solid-fuel powered and fitted with non-truncated toroidal aerospike nozzles. Flown at the Pecos County Aerospace Development Center, Fort Stockton, Texas, the rockets achieved apogees of 26,000 ft (7,900 m) and speeds of about Mach 1.5.

Small-scale aerospike engine development using a hybrid rocket propellant configuration has been ongoing by members of the Reaction Research Society.

In 2020 the TU Dresden and Fraunhofer IWS started their CFDμSAT-Project for research on additively manufactured aerospike-engines. A prototype has already been tested in a test cell at TU Dresden's Institute of Aerospace Engineering, achieving a burn time of 30 seconds. [7]

Implementations

Firefly Aerospace

In July 2014 Firefly Space Systems announced its planned Alpha launcher that uses an aerospike engine for its first stage. Intended for the small satellite launch market, it is designed to launch satellites into low-Earth orbit (LEO) at a price of US$8–9 million, much lower than with conventional launchers. [8]

Firefly Alpha 1.0 was designed to carry payloads of up to 400 kilograms (880 lb). It uses carbon composite materials and uses the same basic design for both stages. The plug-cluster aerospike engine puts out 90,000 pounds-force (400 kN) of thrust. The engine has a bell-shaped nozzle that has been cut in half, then stretched to form a ring with the half-nozzle now forming the profile of a plug. [8]

This rocket design was never launched. The design was abandoned after Firefly Space Systems went bankrupt. A new company, Firefly Aerospace, has replaced the aerospike engine with a conventional engine in the Alpha 2.0 design. However, the company has proposed Firefly Gamma, a partially reusable spaceplane with aerospike engines.

ARCA Space

In March 2017 ARCA Space Corporation announced their intention to build a single-stage-to-orbit (SSTO) rocket, named Haas 2CA, using a linear aerospike engine. The rocket is designed to send up to 100 kg into low-Earth orbit, at a price of US$1 million per launch. [9] They later announced that their Executor Aerospike engine would produce 50,500 pounds-force (225 kN) of thrust at sea level and 73,800 pounds-force (328 kN) of thrust in a vacuum. [10]

In June 2017, ARCA announced that they would fly their Demonstrator3 rocket to space, also using a linear aerospike engine. This rocket was designed to test several components of their Haas 2CA at lower cost. They announced a flight for August 2017. [9] In September 2017, ARCA announced that, after being delayed, their linear aerospike engine was ready to perform ground tests and flight tests on a Demonstrator3 rocket. [9]

On December 20, 2019, ARCA tested the LAS 25DA aerospike steam rocket engine for the Launch Assist System. [11]

KSF Space and Interstellar Space

Another spike engine concept model, by KSF Space and Interstellar Space in Los Angeles, was designed for orbital vehicle named SATORI. Due to lack of funding, the concept is still undeveloped. [12]

Rocketstar

Rocketstar planned to launch its 3D-printed aerospike rocket to an altitude of 50 miles in February 2019 but canceled the mission three days ahead of liftoff citing safety concerns. They are working on a second launch attempt. [13]

Pangea Aerospace

In November 2021, Spain-based Pangea Aerospace began hot-fire testing of its small-scale demonstration methane-oxygen aerospike engine DemoP1. [14] [15]

After successfully testing the demonstrator DemoP1, Pangea plans to up-scale to the 300 kN ARCOS engine. [16]

Stoke Space

Headquartered in Kent, Washington, Stoke Space is building and testing a distributed architecture LH2/LOX aerospike system for its reusable second stage. [17]

Polaris Spaceplanes

The Bremen-based German startup POLARIS Raumflugzeuge GmbH received a Bundeswehr contract to design and flight test a linear aerospike engine in April 2023. The company is set to test this new engine on board of its fourth spaceplane demonstrator, DEMO-4 MIRA, in late 2023 [18] [19] at Peenemünde, [20] where the V-2 rockets were developed.

The original MIRA demonstrator was catastrophically damaged in a runway accident in February 2024. [21]

On 29 October 2024, the company was the first ever to ignite an aerospike engine in a flight over the Baltic Sea, powering a four-engine, kerosene-fueled, turbojet MIRA-II demonstrator. The test involved a three-second burn to collect data with minimal engine stress. The vehicle achieved an acceleration of 4 m/s², producing 900 newtons of thrust. [22] [23]

Bath Rocket Team

Based at the University of Bath, the Bath Rocket Team has been developing their own hybrid rocket engine with an aerospike nozzle since 2020. The engine was first tested at the UK Race to Space National Propulsion Competition in 2023. [24] The team is developing a flight-ready version of the engine they are planning to fly for the first time at EuRoC24. [25]

SpaceFields

SpaceFields, incubated at IISc, has successfully tested India's first AeroSpike Rocket Engine at its Challakere facility on 11-Sep-2024. The engine achieved a peak thrust of 2000N and featured altitude compensation for optimal efficiency. [26]

See also

Related Research Articles

<span class="mw-page-title-main">Rocket</span> Vehicle propelled by a reaction gas engine

A rocket is a vehicle that uses jet propulsion to accelerate without using any 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.

<span class="mw-page-title-main">Single-stage-to-orbit</span> Launch system that only uses one rocket stage

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 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.

<span class="mw-page-title-main">Rocket engine</span> Non-air breathing jet engine used to propel a missile or vehicle

A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accordance with Newton's third law. Most rocket engines use the combustion of reactive chemicals to supply the necessary energy, but non-combusting forms such as cold gas thrusters and nuclear thermal rockets also exist. Vehicles propelled by rocket engines are commonly used by ballistic missiles and rockets. Rocket vehicles carry their own oxidiser, unlike most combustion engines, so rocket engines can be used in a vacuum to propel spacecraft and ballistic missiles.

<span class="mw-page-title-main">Rotary Rocket</span> Company

Rotary Rocket Company was a rocketry company that developed the Roton concept in the late 1990s as a fully reusable single-stage-to-orbit (SSTO) crewed spacecraft. The design was initially conceived by Bevin McKinney, who shared it with Gary Hudson. In 1996, Rotary Rocket Company was formed to commercialize the concept. The Roton was intended to reduce costs of launching payloads into low Earth orbit by a factor of ten.

<span class="mw-page-title-main">VentureStar</span> Human-rated re-usable spaceplane concept

VentureStar was a single-stage-to-orbit reusable launch system proposed by Lockheed Martin and funded by the U.S. government. The goal was to replace the Space Shuttle by developing a re-usable spaceplane that could launch satellites into orbit at 1/10th of the cost. While the requirement was for an uncrewed launcher, it was expected to carry passengers as cargo. The VentureStar would have had a wingspan of 68 feet (20.7 m), a length of 127 feet (38.7 m), and would have weighed roughly 1000 t.

<span class="mw-page-title-main">Space Shuttle Solid Rocket Booster</span> Solid propellant rocket used to launch the Space Shuttle orbiter

The Space Shuttle Solid Rocket Booster (SRB) was the first solid-propellant rocket to be used for primary propulsion on a vehicle used for human spaceflight. A pair of them provided 85% of the Space Shuttle's thrust at liftoff and for the first two minutes of ascent. After burnout, they were jettisoned, and parachuted into the Atlantic Ocean, where they were recovered, examined, refurbished, and reused.

<span class="mw-page-title-main">Lockheed Martin X-33</span> Uncrewed re-usable spaceplane technology demonstrator for the VentureStar

The Lockheed Martin X-33 was a proposed uncrewed, sub-scale technology demonstrator suborbital spaceplane that was developed for a period in the 1990s. The X-33 was a technology demonstrator for the VentureStar orbital spaceplane, which was planned to be a next-generation, commercially operated reusable launch vehicle. The X-33 would flight-test a range of technologies that NASA believed it needed for single-stage-to-orbit reusable launch vehicles, such as metallic thermal protection systems, composite cryogenic fuel tanks for liquid hydrogen, the aerospike engine, autonomous (uncrewed) flight control, rapid flight turn-around times through streamlined operations, and its lifting body aerodynamics.

<span class="mw-page-title-main">SABRE (rocket engine)</span> Synergetic Air Breathing Rocket Engine - a hybrid ramjet and rocket engine

SABRE is a concept under development by Reaction Engines Limited for a hypersonic precooled hybrid air-breathing rocket engine. The engine is designed to achieve single-stage-to-orbit capability, propelling the proposed Skylon spaceplane to low Earth orbit. SABRE is an evolution of Alan Bond's series of LACE-like designs that started in the early/mid-1980s for the HOTOL project.

<span class="mw-page-title-main">RS-25</span> Space Shuttle and SLS main engine

The RS-25, also known as the Space Shuttle Main Engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is used on the Space Launch System (SLS).

<span class="mw-page-title-main">Rocketdyne J-2</span> Rocket engine

The J-2, commonly known as Rocketdyne J-2, was a liquid-fuel cryogenic rocket engine used on NASA's Saturn IB and Saturn V launch vehicles. Built in the United States by Rocketdyne, the J-2 burned cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) propellants, with each engine producing 1,033.1 kN (232,250 lbf) of thrust in vacuum. The engine's preliminary design dates back to recommendations of the 1959 Silverstein Committee. Rocketdyne won approval to develop the J-2 in June 1960 and the first flight, AS-201, occurred on 26 February 1966. The J-2 underwent several minor upgrades over its operational history to improve the engine's performance, with two major upgrade programs, the de Laval nozzle-type J-2S and aerospike-type J-2T, which were cancelled after the conclusion of the Apollo program.

<span class="mw-page-title-main">Linear Aerospike SR-71 Experiment</span> Linear Aerospike SR-71 Experiment 1997/8 NASA for X-33

LASRE was NASA's Linear Aerospike SR-71 Experiment which took place at the Dryden Flight Research Center at Edwards Air Force Base, California, until November 1998. The experiment sought to provide flight data to help Lockheed Martin validate and tune the computational predictive tools used to determine the aerodynamic performance of the Lockheed Martin X-33 lifting body and linear aerospike engine combination and to lay groundwork for a future reusable launch vehicle.

This is an alphabetical list of articles pertaining specifically to aerospace engineering. For a broad overview of engineering, see List of engineering topics. For biographies, see List of engineers.

<span class="mw-page-title-main">NK-33</span> Soviet rocket engine

The NK-33 and NK-43 are rocket engines designed and built in the late 1960s and early 1970s by the Kuznetsov Design Bureau. The NK designation is derived from the initials of chief designer Nikolay Kuznetsov. The NK-33 was among the most powerful LOX/RP-1 rocket engines when it was built, with a high specific impulse and low structural mass. They were intended for the ill-fated Soviet N1F Moon rocket, which was an upgraded version of the N1. The NK-33A rocket engine is now used on the first stage of the Soyuz-2-1v launch vehicle. When the supply of the NK-33 engines are exhausted, Russia will supply the new RD-193 rocket engine. It used to be the first stage engines of the Antares 100 rocket series, although those engines are rebranded the AJ-26 and the newer Antares 200 and Antares 200+ rocket series uses the RD-181 for the first stage engines, which is a modified RD-191, but shares some properties like a single combustion chamber unlike the two combustion chambers used in the RD-180 of the Atlas V and the four combustion chambers used in the RD-170 of the Energia and Zenit rocket families, and the RD-107, RD-108, RD-117, and RD-118 rocket engines used on all of the variants of the Soyuz rocket.

<span class="mw-page-title-main">ARCAspace</span> Aerospace company headquartered in Romania

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 several rocket systems, both orbital and suborbital, under the EcoRocket program. These vehicles include the CER rocket systems, the EcoRocket Demonstrator, Nano, 5 & Heavy, and the A1 strategic anti-ballistic interceptor. ARCA has yet to launch a vehicle above the Karman line, or sent a payload to orbit, with the majority of their projects having been abandoned due to various reasons, often including financial or regulatory constraints.

<span class="mw-page-title-main">Rocket engine nozzle</span> Type of propelling nozzle

A rocket engine nozzle is a propelling nozzle used in a rocket engine to expand and accelerate combustion products to high supersonic velocities.

<span class="mw-page-title-main">Air-launch-to-orbit</span> Method of launching rockets at altitude from a conventional horizontal-takeoff aircraft

Air-launch-to-orbit (ALTO) is the method of launching smaller rockets at altitude from a heavier conventional horizontal-takeoff aircraft, to carry satellites to low Earth orbit. It is a follow-on development of air launches of experimental aircraft that began in the late 1940s. This method, when employed for orbital payload insertion, presents significant advantages over conventional vertical rocket launches, particularly because of the reduced mass, thrust, cost of the rocket, geographical factors, and natural disasters.

An altitude compensating nozzle is a class of rocket engine nozzles that are designed to operate efficiently across a wide range of altitudes.

The expansion-deflection nozzle is a rocket nozzle which achieves altitude compensation through interaction of the exhaust gas with the atmosphere, much like the plug and aerospike nozzles.

<span class="mw-page-title-main">Rocket sled launch</span> Proposed method for launching space vehicles

A rocket sled launch, also known as ground-based launch assist, catapult launch assist, and sky-ramp launch, is a proposed method for launching space vehicles. With this concept the launch vehicle is supported by an eastward pointing rail or maglev track that goes up the side of a mountain while an externally applied force is used to accelerate the launch vehicle to a given velocity. Using an externally applied force for the initial acceleration reduces the propellant the launch vehicle needs to carry to reach orbit. This allows the launch vehicle to carry a larger payload and reduces the cost of getting to orbit. When the amount of velocity added to the launch vehicle by the ground accelerator becomes great enough, single-stage-to-orbit flight with a reusable launch vehicle becomes possible.

<span class="mw-page-title-main">Firefly Alpha</span> Two-stage operational orbital rocket, about 1,070 kg to LEO

Firefly Alpha is a two-stage orbital expendable small lift launch vehicle developed by the American company Firefly Aerospace to compete in the commercial small satellite launch market. Alpha is intended to provide launch options for both full vehicle and rideshare customers.

References

  1. 1 2 3 4 5 "NASA - Linear Aerospike Engine fact sheet (08/00)". www.nasa.gov. Archived from the original on 18 July 2023. Retrieved 21 January 2020.
  2. ↑ Defusca, Albert; Craddock, Christopher (1 November 2017). "Affordable Access to Low Earth Orbit". DSIAC Journals. 4 (4). Archived from the original on 25 December 2021. Retrieved 16 June 2019.
  3. ↑ "Aerospike Engine Homepage". www.hq.nasa.gov. Archived from the original on 23 May 2022. Retrieved 27 August 2020.
  4. ↑ "Pwrengineering.com". ww17.pwrengineering.com. Archived from the original on 2 April 2010.
  5. ↑ "RS-2200". Astronautix.com. Archived from the original on 28 December 2016. Retrieved 4 February 2018.
  6. ↑ "CSULB CALVEIN Rocket News and Events". Archived from the original on 15 June 2008.
  7. ↑ "TU-Dresden Homepage". tu-dresden.de. Retrieved 23 April 2021.
  8. 1 2 "Firefly Space Systems unveils Alpha launch vehicle design with aerospike engine". Gizmag.com. 14 July 2014. Retrieved 14 July 2014.
  9. 1 2 3 "ARCA News". ARCA Space. Archived from the original on 23 November 2022. Retrieved 30 May 2018.
  10. ↑ "Haas 2CA Specs". ARCA Space. Archived from the original on 30 May 2018. Retrieved 30 May 2018.
  11. ↑ "Flight of the Aerospike: Episode 34 - LAS 25DA Aerospike Engine". Youtube. ARCA Space. 30 December 2019. Archived from the original on 11 December 2021. Retrieved 5 August 2020.
  12. ↑ "SATORI Space Vehicle Rocket". KSF Space.
  13. ↑ "RocketStar ready for second suborbital flight attempt". SpaceNews. 27 September 2021. Retrieved 14 December 2021.
  14. ↑ "Pangea Aerospace tests aerospike engine". SpaceNews. 20 November 2021. Retrieved 2 January 2022.
  15. ↑ "Research Activities in the Development of DemoP1: A LOX/LNG Aerospike Engine Demonstrator". ResearchGate. March 2021. Retrieved 22 December 2022.
  16. ↑ "Aerospike Propulsion". Pangea Aerospace. Retrieved 22 December 2022.
  17. ↑ "Stoke Space aims to build rapidly reusable rocket with a completely novel design". Arstechnica. 10 October 2022. Retrieved 13 February 2023.
  18. ↑ "POLARIS Raumflugzeuge - POLARIS receives Bundeswehr Study Contract for Linear Aerospike Rocket Engine Design and Flight-Testing". polaris-raumflugzeuge.de (in German). Retrieved 25 July 2023.
  19. ↑ Andrew Parsonson (25 August 2023). "POLARIS Spaceplanes Begins Testing its MIRA-Light Vehicle". European Spaceflight.
  20. ↑ "Aus "ATHENA" wird "NOVA" - Unbemanntes Raumflugzeug getestet". 13 March 2023.
  21. ↑ "POLARIS Raumflugzeuge - Demonstrators". polaris-raumflugzeuge.de. Retrieved 12 November 2024.
  22. ↑ Parsonson, Andrew (12 November 2024). "POLARIS Spaceplanes Complete First In-Flight Rocket Engine Ignition". European Spaceflight. Retrieved 12 November 2024.
  23. ↑ Salas, Joe (8 November 2024). "World's first aerospike rocket test mid-flight successful". New Atlas. Retrieved 12 November 2024.
  24. ↑ "National Propulsion Competition". UK RACE TO SPACE. Retrieved 21 March 2024.
  25. ↑ "Bath Rocket Team on LinkedIn: #ukrace2space #rocketscience #rockets #propulsion #team #engineering…". www.linkedin.com. Retrieved 21 March 2024.
  26. ↑ "IISc-incubated startup hot-tests aerospike rocket engine". Times of India. 11 September 2024. Retrieved 12 September 2024.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.