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STARCHASER AUTOMATED MANUFACTURE OF SPACE LAUNCH VEHICLES



STARCHASER ARE PROPOSING TO USE THE CHURCHILL
MK3 FIRINGS AS A TESTING OPPORTUNITY FOR A NEW
AUTOMATED MANUFACTURING PROCESS FOR SPACE
LAUNCH VEHICLES.

To investigate the possibilities for automated manufacture,
Starchaser has proposed to apply these techniques to the
fabrication of their next rocket engine frame. Working together with
several partners that are interested in the process, a wealth of
knowledge can be gained from the static test firings that
Starchaser will be carrying out.

If Europe wishes to stay in the business of manufacturing satellite
launch vehicles and space structures they face tremendous
competition from low cost and established launch systems from
the USA, China,and Russia.

The automotive industry may have an answer to assist Europe's
Space efforts with a process that is successfully employed by
Jaguar on its new all aluminium Sports X350 car. The automotive
industry is a very competitive industry with the vehicle
manufacturers all looking for more economical ways of
manufacturing their products.

The demand for low emission vehicles have forced engineers to
look at low weight materials such as aluminium and composites.
Jaguar has selected the use of aluminium for its new light-weight all
aluminium monocoque Jaguar X350 Sports.

The Self-Piercing Rivet (SPR) process was chosen as the most
appropriate method of fastening a small volume production run.

Besides Jaguar, the Ford GT40 muscle car, BMW, Audi and
LandRover are using the SPR as their choice automated fastening
method. There are many other impressive examples available of the
use of this effective SPR technology.

For Europe to remain in the Space Launch producer field, rocket
launch structures such as Ariane 5 and now the Italian inspired
Vega launcher, cost must be reduced. The transfer of established
SPR technology from the automotive industry to specific rocket
structures presents real opportunities to cost save by labour
reduction and automation.


ENGINE SUPPORT FRAMES



Rocket manufacturers are familiar with the thin skin and stringers
construction of aircraft structures. In fact engine support frames on
the first stage and stage to orbit of the Ariane 5 are designed by
former aircraft manufacturers as stringer structures [and built by
them].

Ariane 5 first stage and the final stage to orbit includes the Engine
support Frames BME and ESCA. These structures are essentially
'thin sheet and stringer' construction of similar shape fastened by
standard rivet types and methods which are labour intensive. Both
ESCA and BME fullfill the role of rocket engine load transfer into
main rocket structure. Internally the thin conical structure is
stiffened with riveted top-hat section stringers.

The process of manufacture is labour intensive and therefore costly.


SELF PIERCING RIVETS



Unlike conventional rivets, SPRs do not require a pre-drilled hole.
The rivet is driven into the materials to be joined at high force,
piercing the top sheets and spreading outwards into the bottom
sheet of material. The bottom sheet of material is pushed into a die
forming a shaped button of material. This action forms a strong
robust joint.

SPR hand and Automated Systems:
Electric or hydraulic riveting tools can be used and the fastening
process can be hand applied or automated.


APPLICATION TO ROCKET STRUCTURES



The application of SPR technology brings great cost benefits to the
automotive industry making specialised low volume production cost
effective. It is possible when this technology is transferred to the
manufacture of Space products, similar cost savings will be
recognised.

Some of the benefits of SPR are listed

No pre-drilled holes required. Hence labour cost reduction.
No pre-drilled hole edge cleaning necessary.
Can be a manual or automated process. Automation offers 2-3
seconds
  rivet installation time.

Joins dissimilar materials, steel, aluminium, plastic.
No heat, fumes, dust or swarf is generated.
Compatible with adhesives and lubricants.
Fast cycle time.
Low noise operation.

Initial estimates suggest that the application of the SPR process to
the manufacture of rocket structures will remove at least two labour
intensive activities and will significantly reduce cost to manufacture.

Specific generic rocket structural components are formed of thin
aluminium sheet and stringers-standard aerospace design
philosophy.


RESEARCH OBJECTIVE


By applying the SPR technology to specific rocket structural items, such as an Engine Transition Module, (ETM),
it is the intention of this research project to demonstrate the significant cost benefits and the effective potential of
an automated fastening process.


THE STARCHASER THUNDERSTAR CONCEPT


A concept that Starchaser has undertaken to develop, a launch system capable of meeting the requirements of the
Space Tourism, is known as the Thunderstar. It is within this program that such a rocket structure must exhibit the
structural integrity to withstand all mission phase loadings, such as static, dynamic, aerodynamic, acoustic and
thermal. Furthermore the structure must meet cost budgets and mass targets.

By definition rockets are cylindrical. An efficient lightweight rocket structure will be a thin cylinder and can be
sensitive to failure by global buckling mode initiated by thrust loadings from the main engines. It is essential that
smooth load transfer is directed from the engines through the ETM into the main rocket cylinder structure.

A Beam engine frame configuration may introduce local high spot loadings whereas the conical arrangement
ensures a more evenly distributed load transfer into the thin cylinder.


ENGINE TRANSITION MOUNTING (ETM)



The following design of ETM shown in the sketches below has been
formulated so that the Self-Pierced Rivet fastening process can be
used and that manufacturing cost can be minimized.

Upper and lower rims are seen in place. Each are multi-facetted
components, similar to a 50 pence piece.

The significant advantage offered, is that simple sub-assemblies of
flat-panels and  SPR top-hat stringers can be fastened peripherally
around the structure onto the each corresponding upper and lower
rim facet.

The stringers of the sub-assemblies are fastened to the flat panels
using the SPR  method.

The number of facets required will be influenced by:

Manufacturing requirements, such as fastener head size, tooling
reach, etc.
An Optimum number of panels to achieve an acceptable level of
applied stress.

Further, the ETM,

Comprises of an Central Engine Nib (CEN).This is envisaged as a
spoke type
  structure attached to the lower Rim.

The engine is centrally mounted on the CEN and the propulsive
loads are
  transferred into the segmented cone structure. The interface is by
the Upper
  rim into the main rocket cylinder.


THE FLAT PANEL SUB ASSEMBLIES



Initially, the top-hat stringers will be fastened on the flat panels
using a hand operated SPR system, such as shown in the photo
left.

The SPR fastening process of the stringers to the flat panel will
then be automated.


THE FABRICATION OF THE ETM


The top and bottom rims will be held in place whilst robotic assembly techiques like those used in the automotive
industry will SPR fasten the panels in place.

Traditional rivet fastening techniques are for todays rocket launch structures labour intensive and therefore costly.

The global cost equation of using fully SPR systems should provide significant cost advantages. It may establish
beneficial methods of automated construction for future launcher projects and space station modules.


TEST CONFIGURATION


The ETM project is not aiming to fabricate and test large structures - smaller generic structures are being
contemplated.

The research will examine many smaller components with a view to optimize their structural and dynamic behavour
leading to their integration into an engine frame.

The generic ETM will be about 1.6metres diameter and about 0.9 metres in height. This size structure will be a
proof of concept structure that will be easy to handle during automated phases, transportable to its final test site
and compatible to the 15 ton Churchill 3 test engine interface.


ROBOTIC AUTOMATION



The fastening of the structure using SPRs and the assembly of the
Jaguar X350 all aluminium car is done by Kawasaki robots. This
robot type could be used on automated trials of the ETM.

The ETM, Rigs and tooling will be designed for the method of
manufacture.

The 15 ton thrust Churchill 3 engine will be mounted on the
complete ETM and the assembly delivered to the test site.


  Collaberators:

Jura Carbon Ltd. United Kingdom.
  Project design and management. Specialist Software JSAMs for the design of Self-Piercing Rivets joints.

Starchaser Ltd. United Kingdom.
  Designer and producer of the Nova rocket launcher system and Churchill engine series.

University of Delft. Holland.
  Extensive experience in aircraft structures, optimisation.


STARCHASER RESEARCH AND DEVELOPMENT - INVITATION


Starchaser will be pleased to accept assistance from any enthusiastic organisation or individuals who have
knowledge in the following areas;

Robotics.
Automation.
Jigs and tooling.
Associated software.
Structural assembly / Structural testing.

If you feel that you can contribute to the project please contact us.

44 (0)161 882 9922

Contact starchaser



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