Space Engineering Helps Drill Better Holes In Planet Earth

ESA News
http://www.esa.int

18 July 2003

Space engineering helps drill better holes in planet Earth

Expertise derived from working on the joint NASA-ESA Cassini-Huygens mission to
Saturn and its moon Titan is now being applied to underground drilling machines.
This is providing tunnelling engineers with an improved ability to virtually
'see' some 40 metres into solid rock and pinpoint obstacles ahead.

It's an old miners' expression: "There is darkness in front of the pick".
Billions of years of geological history has laid down complex folds of strata,
patterns of faulting and embedded irregular objects in the ground beneath our
feet. The character of the earth can and often does change unexpectedly with
every metre excavated.

But with modern high-speed tunnelling, sudden geological shifts may damage the
cutting head of drilling machines and lead to expensive delays in multi-million
Euro excavation projects.

German tunnelling company Herrenknecht AG -- famous for drilling the Elbe tunnel
in Hamburg using the world's single largest tunnelling machine -- has developed
a new method of charting what lies ahead beyond the tunnel face.

Geologists have mapped the deep structure of the Earth by monitoring how seismic
waves from earthquakes echo through our planet. On the same principle but a
smaller scale, seismic waves can be sent through a tunnel face, and significant
discontinuities in the rock mass will reflect waves again back. If necessary
serious obstacles can then be removed, preventing damage to the drilling machine
and reducing overall downtime.

Herrenkneckt AG has originated a way to do this even as drilling carries on.
Their idea is to fit specially adapted transmitters and microphones onto a
drilling machine's rotary shear blades. The transmitters project sound into the
ground every second, while the microphones record seismic reflections. A
computer behind the tunnelling machine evaluates measured and statistical
seismic data to visualise significant geological shifts in the earth ahead.

However the initial transmitter used was a commercial shaker designed for
industrial vibration tests, whose function was not fully satisfactory.
Herrenknecht AG knew all components of a more efficient seismic probing system
would have to be precisely designed to work reliably under the extreme stresses
of the rock face. With on-the-job repair almost impossible, extensive
pre-operational testing was required.

It was this requirement that led Herrenknecht AG engineers to approach MST
Aerospace -- ESA's Technology Transfer broker in Germany -- back in September
1998 to put them in touch with a partner with experience in space-related
mechanical engineering.

"We were looking for a competent partner in acoustic design and vibration
analyses," says Andreas Kassel, a geophysicist with Herrenknecht AG, responsible
for the development of prediction methods for tunnel boring machines (TBMs). "We
contacted MST as we hoped they had already tackled similar vibration problems
for launcher and space missions. We know that for space extreme reliable
technical solutions are needed and that was what we were looking for."

In March 1999 their first meeting took place with Astro- und Feinwerktechnik
Adlershof GmbH, a start-up of Forschungszentrum Berlin-Adlershof of the German
Aerospace Centre DLR. This firm has developed specialist electro-mechanical
hardware for several space mission payloads, most notably ESA's Cosmic Dust
Analyser for the Cassini spacecraft currently on its way to Saturn along with
Huygens, ESA's Titan lander.

In the process the firm also has acquired extensive experience of testing
components for space by simulating extreme conditions, in particular using
vibration actuators. In autumn 2001, Herrenknecht AG awarded Astro- und
Feinwerktechnik Adlershof GmbH the contract to develop a transmitter prototype.

It was delivered the following year and swiftly judged a success: "We found it
achieved improvements in pulse compression and thus in spatial resolution of our
seismic reflection method by an order of magnitude," Kassel explains.

These new seismic probing transmitters have been successfully tested on a
9.8m-diameter TBM shield excavating the 1,600m-long Pannerdensch Kanaal twin
tunnel near Arnhem, part of the Netherlands' new 160km Betuweroute freight
railway line. The transmitters are also due to be installed on two further TBMs
for an excavation in Kuala Lumpur, Malaysia.

Space technology ready for use on Earth

MST Aerospace in Germany is part of ESA's Technology Transfer Programme's
network of technology brokers. The objective is to stimulate the spin-off of
space technologies in the non-space sector.

"Our experience shows that the use of innovative technologies produced for
European space programmes can improve our day-to-day life on Earth," says Pierre
Brisson, head of ESA's Technology Transfer Programme. "Since 1991 when we
started our programme, more than 160 transfers have generated EUR 25 million in
turnover for European space companies and EUR 270 million for the non-space
industries involved."

The virtual market place 'www.technology-forum.com', run by MST Aerospace on
behalf of ESA, is available to European industry to facilitate the process of
technology exchange. Advanced technologies ready and available are presented,
requests for specific technological solutions can be posted, and solutions offered.

Related links

* Herrenknecht AG
http://www.herrenknecht.com
* MST Aerospace
http://www.mst-aerospace.de/
* Astro- und Feinwerktechnik Adlershof GmbH
http://www.astrofein.com/english/indexf.htm
* Betuweroute
http://www.betuweroute.nl/
* Cassini/Huygens
http://sci.esa.int/huygens/

IMAGE CAPTIONS:

[Image 1:
http://www.esa.int/export/esaCP/SEMC..._index_1.html]
Trude, the world's largest tunnel boring machines (TBMs) with a diameter of
14.2m, excavated the 4th pipe Elbe Tunnel in Hamburg, Germany. It took two years
and five months to drill the 2,561 metres underground tunnel.

The German tunnelling company, Herrenknecht AG, responsible for this achievement
is now applying a new technique with space origin in order to be able to drill
tunnels even better. The German company Astro- und Feinwerktechnik Adlershof
GmbH has produced a new transmitter for Herrenknecht AG based upon their
know-how gained from their work for ESA on the Cassini-Huygens spacecraft.

A number of these transmitters are now mounted on a TBM and provides a look into
the ground in front of the TDB. Every second the transmitters send sound waves
into the ground, microphones receive the reflecting signals which are data
processed and visualizes important geologic changes up to 40 m in front of the
rotary shear blade.

Credits: Herrenknecht AG

[Image 2:
http://www.esa.int/export/esaCP/SEMC...html#subhead1]
Huygens will be the first spacecraft to land on a world in the outer Solar
System. In January 2005, it will land on the surface of Titan, Saturn's largest
moon, and the only moon in the Solar System to possess a thick atmosphere. The
Huygens data may offer clues about how life began on Earth. Huygens is currently
in space, hitching a ride on NASA's Cassini mission, which was launched by a
Titan IVB/Centaur rocket on 15 October 1997. In an artist's illustration,
Huygens is here seen in the lower right corner while approaching the
reddish/blue Titan moon below. Cassini is illustrated closer to Saturn.

Credits: ESA

[Image 3:
http://www.esa.int/export/esaCP/SEMC...html#subhead2]
The German company Astro- und Feinwerktechnik Adlershof GmbH has produced new
transmitters for Herrenknecht AG mounted on their tunnel boring machine (TBM)
seen above. Every second the transmitters send sound waves into the ground,
microphones receive the reflecting signals which are data processed and
visualizes important geologic changes up to 40 m in front of the rotary shear
blade. These innovative transmitters have been developed based upon the
expertise Astro gained on their work for ESA on the Cassini-Huygens spacecraft.

Credits: Herrenknecht AG

[Image 4:
http://www.esa.int/export/esaCP/SEMC...html#subhead3]
An air view of the Pannerdensch Kanaal twin tunnel near Arnhem, the Netherlands.
This tunnel was drilled by Herrenknecht AG using a tunnel boring machine (TBM)
with new transmitters spun-off from European space programmes.

Credits: Herrenknecht AG

[Image 5:
http://www.esa.int/export/esaCP/SEMC...html#subhead4]
Here is seen the tunnel boring machine (TBM) break through at the Pannerdensch
Kanaal twin tunnel near Arnhem, the Netherlands. This tunnel was drilled by
Herrenknecht AG using a tunnel boring machine (TBM) with new transmitters
spun-off from European space programmes.

Credits: Herrenknecht AG