JEC COMPOSITES MAGAZINE - Issue #132 - January/February 2020 - 55

The market for ever lighter satellites is growing steadily

Focus
About DLR and its research focus areas
The German Aerospace Center (DLR) is the national aeronautics and
space research centre of the Federal Republic of Germany. The centre
is steering extensive research and development work in aeronautics,
space, energy, transport, digitization and security. DLR has approximately 8,700 employees at 26 locations in Germany, and offices in
Brussels, Paris, Tokyo and Washington D.C. DLR's development in materials and structures focuses on cost reduction for expendable launch
systems or expendable parts of partially reusable space transportation
systems (STS), and on new or improved materials and structural
concepts that allow a high reusability without refurbishment or costly
maintenance. Low-cost structures require a structural design adapted
to optimized, automated manufacturing processes. CFRP materials
promise significant weight savings. Thus cryogenic tank structures
and fairings using adequate resin systems are a major focus area
for further development, considering especially thermoplastics for
improved automated manufacturing processes. Focusing on reusable
systems demands a good knowledge of the mechanical and thermal
fatigue behaviour of the required materials. Structural concepts taking
re-entry loads into account have to be developed. This class of STS also
needs new structural elements such as aerodynamic control elements
and landing devices, which will be exposed to significant thermal loads.
A first stage return, even at low separation speeds (Ma 7), generates
local temperatures above 1000°C and larger areas will be exposed to
temperatures of approximately 400°C. Considering thermal expansion
problems, which mainly occur when using metals, reusable thermal
protective systems (TPS) based on ceramic materials are promising
solutions and have to be further developed to cover the whole temperature range from 200 to 1600°C that is currently covered by expendable,
ablative systems. DLR is also focusing on 3D printing technologies and
related innovative design methods to reduce manufacturing costs and
improve design flexibility for smaller subsystems in rocket engines and
launcher structures.

call these materials "tina" - there
is no alternative.
What demand would you like to
address to the industry? What
are the requirements for the
development of new materials?

Test missile re-entering the earth's atmosphere made of fibre-reinforced ceramics

pany in New Zealand, Rocket
Lab, uses CFRP for the entire
missile structure, the tank and the
main structure. The smaller the
carrier, the more important the
weight factor. Thermoplastics are
a promising material for the future, since their production costs
are considerably lower. Automotive and aviation are setting the
trends, even though the extreme

temperature shifts in aerospace
and the numerous applications
are challenging material experts.
When exploring a planet with its
own atmosphere, such as Mars,
you need different materials. In
this particular case, we talk about
ceramics or fibres integrated in
ceramics, which are ten times
more expensive than standard
CFRP. In earlier times, we used to

H.W.: Above all, materials have
to show temperature resistance
and be manufactured as thermoplastics. In the future, we'll need
to operate in a more interconnected way, in networked systems, and benefit from the new
digitization tools to cope with the
described requirements.
DLR is doing research in smart
space travel structures that can
monitor themselves; self-optimizing
systems that respond to external
influences in a largely autonomous
way. Can you tell us more?

H.W.: Smart structures are rele-

N°132 January - February 2020

vant when it comes to reusability.
Rechecking a space shuttle after
use takes around six months.
Sensors integrated in the structure could provide information
about the condition of materials.
The only problem here is, that
you have an immense wealth of
information and you need a clear
and coherent picture to make decisions. Artificial intelligence can
increasingly support these systems in the evaluation process.

Test missile on the carrier system before take-off

More information:
www.dlr.de
www.compositesy-europe.
com/en/Newsroom/
Ultralight-in-space-market-and-technology-study-examines-lightweight-construction-trends-in-space-travel/
n368/
Isa Hofmann
consultant industry

/ jec composites magazine

http://www.dlr.de https://www.composites-europe.com/en/Newsroom/Ultralight-in-space-market-and-technology-study-examines-lightweight-construction-trends-in-space-travel/n368/

JEC COMPOSITES MAGAZINE - Issue #132 - January/February 2020

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #132 - January/February 2020