Sweden plans to launch satellites using fighter jets

How to send a payload into orbit? The most widespread solution is large, heavy, and expensive carrier rockets, the use of which requires the construction of costly infrastructure. A huge amount of fuel is used in the initial phase of the flight when the rocket lifts off from Earth and overcomes the lowest, dense - generating the greatest resistance - layers of the atmosphere.

This problem can be partially solved by changing the altitude from which the rocket starts and taking it into the air using an aeroplane, better suited for flying in the lower layers of the atmosphere. Although the rocket's size and thus the mass of the payload it carries are limited, a regular airport and aeroplane are sufficient to start the space mission.

This is the idea the Swedes want to realise, having launched the Stella research programme for this purpose. Its launching aligns with Sweden's new "Space Strategy in the Field of Defence and Security," adopted in early July, which aims to "secure Sweden's interests in defence and security in space."

This aligns with NATO's decision to treat outer space as the fifth operational domain, or an area for conducting military operations. The other four are land, sea, air, and cyberspace.

The aim of the Stella programme is to test the possibility of launching small payloads into orbit using a rocket launched from an aircraft. This solution has already been researched by the Royal Institute of Technology KTH in Stockholm. Researchers believe the idea is feasible for small, 2-kg payloads. It's not much, but it's enough to place nanosatellites into orbit.

The Swedish army is interested in the initiative. Colonel Ella Carlsson, head of the Space Department of the Swedish Air Force, stated that the inspiration came from an interview in which a former director of the Ukrainian Space Agency claimed that the ability to quickly place satellites into orbit using an aircraft would have been very desirable before the Russian aggression.

The Swedish military has significant reservations. The continuation of the Stella programme is conditional on confirming that the rocket with the payload can launch from the JAS-39 Gripen aircraft. The main concern is verifying whether this will require modifications to the aircraft itself.

It is worth noting that the Swedes are not the first – similar research was started by the Italians in 2019, who want to use Eurofighter Typhoon aircraft as rocket carriers. Also worth mentioning is the interrupted American ALASA programme.

Run by DARPA, the research programme aimed to test the possibility of launching satellites into orbit with a rocket carried into the air by an F-15 aircraft. According to the programme's assumptions, this was supposed to be a response to the risk of space infrastructure being destroyed during a potential armed conflict.

Although the ALASA programme was abandoned, the idea of quickly carrying out space missions has not been abandoned.

Examples include missions during which – though using traditional Firefly Alpha carrier rockets – the Pentagon tested the ability to rapidly launch payloads into orbit within just a few dozen hours of making such a decision. During the Victus Nox mission carried out in September 2023, the time from decision to launch was just 27 hours Greenwich Time.

This pace allows for the rapid rebuilding of reconnaissance satellite constellations that have been damaged or intentionally destroyed in orbit as a result of enemy actions.

Flying launch platforms, as well as rockets with significantly larger mass, have also been utilised by the Northrop Grumman Pegasus system, in use since the 1990s. Developed by Orbital Sciences Corporation, it uses Pegasus and Pegasus XL rockets up to 18 metres long and weighing up to 23 tonnes.

The three-stage rocket can place a 440-kg payload into low orbit, with the launch carried out from an aircraft (e.g., B-52) that takes the rocket to an altitude of 13 kilometres. To date, 45 different missions have been carried out this way, with the last one taking place in 2021.

A similar solution was developed by Virgin Orbit, using a Boeing 747 aircraft as the launch platform and the LauncherOne rocket. In 2023, its solutions were taken over by Stratolaunch Systems, which operates another flying launch platform - the twin-fuselage, world's largest aircraft Stratolaunch.

In 2022, the Polish Space Agency (POLSA) signed a letter of intent with Virgin Orbit regarding launches from Polish territory using LauncherOne systems.

Poland is also conducting research on using military aircraft as launch platforms for space rockets. The Department of Mechatronics, Armament, and Aviation of the Military University of Technology (WAT), in collaboration with the Łukasiewicz Research Network - Institute of Aviation, has verified, among other things, the possibility of using decommissioned MiG-29 and Su-22 aircraft.

Their use as launch platforms would make Poland – currently building relatively small satellites – independent of the availability of cargo space in rockets carrying larger payloads into orbit for other countries.

"The grand space programmes conducted by the Americans, Russians, Chinese, or Europeans (...) are available only to countries that can afford them. Poles participate in them on a 'piggyback' basis, meaning our payload can be attached to the main payload, and its launch involves several years of waiting in line (…)." – explains Dr. Eng. Piotr Zalewski from WAT.

An important issue in this case is not only the aircraft's lifting capacity but also the availability of an adequately large aviation range. This is necessary for safety reasons – that’s why cosmodromes are built in sparsely populated areas (like Baikonur in Kazakhstan, ELS in French Guiana, Andoya in Norway, or Esrange in Sweden), or – as in the case of the U.S. – over the ocean, where a potential rocket disaster would not cause damage on the ground.

"It is realistic to place a rocket with a satellite, for example, under the wings or fuselage of an aircraft that will take off from an airport in Poland and fly over the North Sea, where the rocket will detach and complete its flight in a safe zone. We would not then be dependent on Americans or the European Agency, and we wouldn't have to wait in line to attach to a large payload" – notes Dr. Eng. Zalewski.

Research conducted in Poland confirmed that – after modification – the decommissioned aircraft would be capable of lifting rockets weighing 2 to 4 tonnes. "Considering the performance and capabilities of some fighter aircraft, a rocket with the required parameters can be carried by them. This means that a space payload weighing 10 kg can be launched into so-called low Earth orbit (500 to 700 kilometres)" – the researchers concluded.