Tag: aerospike engine

Dubai-based AI/3D printing company successfully test fires an aerospike engine

9:15 am

LEAP71's aerospike test engine
Click for original image.

The Dubai-based startup LEAP71, focused on using AI software to quickly develop rocket engine designs it can then 3D print, has successfully test fired a prototype aerospike engine on December 18, 2024 during a static fire test campaign conducted in the United Kingdom.

Aerospikes are more compact and significantly more efficient across various atmospheric pressures, including the vacuum of space. They forego the conventional bell-shaped nozzle by placing a spike in the center of a toroidal combustion chamber [as shown in the photo to the right]. Since it is surrounded by 3,500ºC hot exhaust gas, cooling the spike is an enormous challenge.

Josefine Lissner, CEO and Co-Founder of LEAP 71, stated: “We were able to extend Noyron’s physics to deal with the unique complexity of this engine type. The spike is cooled by intricate cooling channels flooded by cryogenic oxygen, whereas the outside of the chamber is cooled by the kerosene fuel. I am very encouraged by the results of this test, as virtually everything on the engine was novel and untested. It’s a great validation of our physics-driven approach to computational AI.”

The spike in the center acts as one wall of the nozzle, and the changing pressure of the atmosphere acting as the other side of the nozzle, allowing the nozzle size to change as the rocket rises, thus making its thrust as efficient as possible.

This test was apparently with a small scale prototype, not a full scale engine. LEAP71 engineers are going to have to go though a lot more iterations using their AI software and 3D printing to get to a version usable on a rocket. The company claims that development will go far faster this way. That this company did its testing in the UK but is based in Dubai suggests its capital comes from that Middle Eastern country, which is trying to develop a space industry of its own, but it is mainly relying on British designers — at this point — to get things done.

It will have to do so quickly, since another startup, German-based Polaris Spaceplanes, in November 2024 actually completed the first test flight ever of a prototype using an aerospike engine.

After decades of speculation about the advantages of an aerospike engine but no successful flights, we now have a race between two companies to be the first to fly one, and the effort is going on in Europe.

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Polaris completes first inflight ignition of its aerospike engine

12:08 am

In what appears to be a first, Polaris Spaceplane on October 29, 2024 successfully completed the first ever inflight ignition of an aerospike engine, using its Mira-2 unmanned engineering prototype.

Later in the day on 29 October, MIRA II took off from Peenemünde Airport on the coast of the Baltic Sea with a takeoff mass of 229 kilograms, which represented a reduced propellant load. The vehicle flew to the ignition point over the Baltic Sea, approximately 3 kilometres away from the ground station, and once there, completed a short three-second burn of its AS-1 aerospike engine. During the short burn, MIRA II experienced an acceleration of 4 m/s².

According to the company, the engine operated at a reduced chamber pressure during the three-second burn, resulting in a fuel-rich combustion.

There have been several attempts in the past to develop the aerospike engine, none of which ever completed any test flights, as far as I am aware. The concept is that the thrust is released in a string of openings, with only one wall forming the nozzle shape and the atmosphere used to complete the nozzle on the other side. As the atmospheric density changes the nozzle shape thus changes its shape, producing the most efficient thrust throughout the engine’s entire flight.

More test flights will be required before the company will be able to begin work on its full scale Aurora spaceplane.

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Polaris Spaceplanes begins test flights of its second Mira prototype

9:42 am

After losing its first Mira prototype test plane during a flight in May, the German startup Polaris Spaceplanes has now begun test flights of its replacement, dubbed Mira-2.

With this prototype the company hopes to test its aerospike engine in flight for the first time, leading to the construction of its full scale spaceplane Aurora.

This five-metre-long vehicle is equipped with jet engines for take-off and landing and one of the company’s in-house developed AS-1 aerospike engines for rocket-powered flight.

POLARIS conducted the first three test flights of the MIRA II demonstrator at the Peenemünde Airport on the coast of the Baltic Sea. Over the three flights, the vehicle accumulated a total of 20 minutes of flight time and covered more than 50 kilometres.

All three flights were unmanned, as Mira-2 is relatively small. The company will now install the aerospike engine, with the next flights testing that engine. If successful, it would be the first time ever an aerospike rocket engine has ever flown.

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German startup loses prototype of aerospike spaceplane during test

9:44 am

The prototype aerospike test spaceplane of the German startup Polaris Spaceplanes was destroyed recently during its first test flight.

The MIRA I, from German aerospace startup Polaris Raumflugzeuge, was traveling at approximately 105 mph during takeoff when a “landing gear steering reaction” plus a side wind caused a “hard landing event,” rendering the space plane inoperable and it’s fiberglass airframe damaged beyond repair.

Its subsystems remained mostly intact – however, rather than attempt to repair the prototype spaceplane, Polaris has opted to decommission 13.9-foot-long MIRA I to go ahead with the identically shaped 16 foot MIRA II and III design.

Had it flown, it would have been the first flight test ever of an aerospike nozzle. Such a nozzle has been proposed by engineers for decades to take full advantage of the changing atmospheric pressure as a rocket lifts off. Traditional nozzles can only be shaped for one specific air pressure, and lose efficiency as the pressure changes. By using the air pressure to form one wall of the nozzle, an aerospike uses that changing pressure to always function at the highest efficiency.

The company hopes to use this design to eventually create a spaceplane that will take off from a runway, reach orbit, and then return to a runway, all without any additional stages.

Neither of the upcoming prototypes however will be able to do this. Their purpose will mostly be to test the aerospike engine at various altitudes. The company hopes to fly its full scale spaceplane, dubbed Aurora, in ’26 or ’27.

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German space plane company completes test program of prototype

10:37 am

The German space plane company Polaris Spaceplanes had now completed a 15-flight test program of the small prototype of its planned orbital and suborbital spaceplane.

The test-flights took place over the course of three days, between Aug. 22 and Sep. 8, and were meant to demonstrate the vehicle’s aerodynamics and flight control systems in preparation for a larger-scale spaceplane prototype the company plans to equip with a linear aerospike rocket engine.

MIRA-Light measures just 8.2 feet (2.5 meters) long, and flies using four electric fans. For 10 of MIRA-Light’s 15 flights, the mini-spaceplane was equipped with a mock aerospike engine to simulate its impact on vehicle performance. In total, the prototype accumulated about 40 total minutes of flight time, according to a report from European Spaceflight.

What makes this project interesting is its use of an aerospike engine, a rocket-engine concept that has been around for decades but never successfully implemented. If successful here, it will make the engines of Polaris’ spaceplane very efficient.

The company now plans a series of test programs using prototypes of increasing size, leading to flying its full-scale hypersonic space plane Aurora on commercial suborbital and orbital flights in ’26 or ’27.

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Aerospike engine ready for ground tests

1:50 pm

Capitalism in space: A demonstrator aerospike rocket engine being developed by ARCA Space is now ready [pdf] for ground tests.

The system will perform a series of ground tests that will ultimately qualify the engine for flight. After the ground tests, the same engine will be integrated into the Demonstrator 3 rocket that will perform a suborbital space flight up to an altitude of 120 km above the New Mexico desert. It will be the first ever flight of a linear aerospike engine and the first ever space flight of an aerospike engine.

Based on the results from these tests the company then intends to build a single-stage-to-orbit small rocket that they hope to fly by 2018.

Go to the company’s news website here to see some good images of the engine and the aerospike nozzle. It does not look like any typical rocket engine. If this effort is successful it will as significant a technological improvement to rocketry as SpaceX’s recovery and reuse of its Falcon 9 first stage.

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New smallsat rocket company plans first flight of aerospike engine

9:09 am

ARCA Aerospace has announced that it will perform the first test flight reaching space of an aerospike rocket engine this coming August.

ARCA Space Corporation has announced the first test-launch of its Demonstrator 3 space vehicle at Spaceport America in August. This will mark the first space flight of an aerospike rocket engine. Aerospike rocket engines are described as significantly more fuel efficient than the current engines and could make launches attempting to bring satellite payloads to space more affordable. Demonstrator 3 will perform a suborbital space flight up to an altitude of 100 kilometers above the New Mexico desert.

Their goal is to build a rocket they have dubbed Haas 2CA for the smallsat industry.

There is an interesting video at the link from the company showing their engineers hand-building this first suborbital test rocket, which the company also says is the first of a weekly series leading up to the test launch. More information about the company can be found at their website. According to their schedule, they hope to make the first orbital flight in 2018, and begin commercial operations by the end of that year.

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