14. November 2018
Aerospace technology: EU SMILE project

DLR is de­vel­op­ing a reusable rock­et en­gine for launch­ing small satel­lites

Rocket engine during the hot test
Rock­et en­gine dur­ing the hot test
Image 1/2, Credit: ©DLR.

Rocket engine during the hot test

The first hot fir­ing test was on the high-pres­sure test rig of the SMILE project part­ner PLD Space.
Components of the reusable rocket engine for small satellites
Com­po­nents of the reusable rock­et en­gine for small satel­lites
Image 2/2, Credit: ©DLR.

Components of the reusable rocket engine for small satellites

Cen­tral com­po­nents of the rock­et en­gine de­vel­oped at the DLR In­sti­tute of Struc­tures and De­sign are the 3D print­ed in­jec­tor head and the ce­ram­ic com­bus­tion cham­ber.
  • DLR researchers have developed a reusable rocket engine specifically for the launch of small satellites.
  • The rocket engine consists of two central components: a metal injector head manufactured by means of metal 3D printing and a ceramic combustion chamber.
  • Small satellites have the potential to fundamentally change the space industry.
  • Focus: space, small satellites, new manufacturing technologies, fibre ceramics

Whether alone or in a constellation, small satellites weighing from just a few kilograms (nanosatellites) up to several hundred kilograms (micro- and minisatellites) are becoming increasingly technologically sophisticated and have the potential to fundamentally change the space industry. In the coming years, hundreds of such small satellites will be carried into Earth orbit. As part of the EU project SMILE (Small Innovative Launcher for Europe), researchers from the Institute of Structures and Design at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) have developed a reusable rocket engine especially for launching such satellites, and have performed an initial series of successful trials on a test rig.

Small satellite launches – Independent, flexible and cost-effective

Until now, small satellites have tended to be carried into space aboard large rockets, if there is enough room for them. The primary aim of these flights is to place large satellites in a specific orbit. Small satellites take second place as far as timing and target orbit are concerned. For this reason, 14 European research institutions and companies are working on designing an economical rocket launcher within the SMILE project. This should enable small satellites weighing up to 70 kilograms to be carried to near-Earth orbits. The project focuses on the technology required for propulsion, on-board electronics and cost-effective production.

3D printing as a success factor

The rocket engine, developed by DLR scientists specifically for this application, consists of two central components – the metal injector head and the ceramic combustion chamber. Belgian project partner 3D Systems manufactured the prototype injector out of a nickel-chromium alloy using metal 3D printing. 3D printing is an additive process. Digital design data is used to build up or rather print the desired structure in layers by depositing material. "Thanks to this relatively new manufacturing technology, we need significantly fewer parts and process steps, which speeds up the manufacturing process for the injector and reduces production costs. At the same time, we have been able to significantly reduce the mass of the components, which is always a very important factor in aerospace applications," says Markus Kuhn, responsible for the project at the DLR Institute of Structures and Design in Stuttgart.

Combustion chamber made of high-performance ceramics

The researchers used a special high-performance material for the combustion chamber – a carbon fibre-reinforced ceramic that consists mainly of silicon carbide and was developed primarily at the DLR institute in Stuttgart. It is particularly well-suited for high-temperature applications and reliably withstands even extreme temperature changes. "Reusability was an important consideration in development. If the entire system can be used multiple times, operating costs are significantly reduced, making commercial implementation attractive to companies," says Ilja Müller, Rocket Propulsion Systems Engineer at the Institute of Structures and Design.

First tests passed with flying colours

In hot firing tests in September 2018, the team led by DLR researcher Markus Kuhn subjected the rocket engine to an initial test run. It successfully completed a total of 18 tests at the high-pressure test bench of Spanish project partner PLD Space, with a firing time of up to 45 seconds, thereby showing very high combustion efficiency of over 90 percent. Liquid oxygen (LOx) and kerosene were used in the tests.

Contact
  • Denise Nüssle
    Cor­po­rate Com­mu­ni­ca­tions, Stuttgart and Ulm
    Ger­man Aerospace Cen­ter (DLR)

    Pub­lic Af­fairs and Com­mu­ni­ca­tions
    Telephone: +49 711 6862-8086
    Fax: +49 711 6862-636
    Pfaffenwaldring 38-40
    70569 Stuttgart
    Contact
  • Ilja Müller
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Struc­tures and De­sign
    Telephone: +49 711 6862-448
    Pfaffenwaldring 38-40
    70569 Stuttgart
  • Markus Kuhn
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Struc­tures and De­sign
    Telephone: +49 711 6862-8408
    Pfaffenwaldring 38-40
    70569 Stuttgart

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