www.davidson.com.au - Kayser-Threde Miniaturised Crash Test Systems

We at Kayser-Threde are very proud that the European Space Agency has selected our MINIDAU® System for an important project on the International Space Station. This article explains our role and involvement in this project:

Crash Testing in Space

The engineering staff at Kayser-Threde GmbH (Munich, Germany) was surprised when asked by the European Space Agency (ESA) to supply a crash test data acquisition system to be used in a space flight application. Kayser-Threde manufactures crash test measurement systems for the automotive industry and also designs and manufactures "space qualified" measurement systems for the aerospace industry. It was the request by the ESA to combine the two technologies that was the real surprise. After a review of the application, the purpose of the request became clear and Kayser-Threde was the logical choice to provide the required measurement system.

Kayser-Threde, founded in 1966, has been involved in many space related projects. An early specialty of the company was the capability to design rugged measurement systems to be used in space flight and orbiting applications. This capability was expanded in 1976 when the German authority for road and traffic safety, Bundesanstalt für Straßenwesen, contacted Kayser-Threde with the suggestion to put a ruggedized data acquisition system on-board a crash vehicle to record data during the impact. At first sight this appeared to be an easy task for the experienced design engineers at Kayser-Threde. However, when they looked into this new application, they found that the requirements for an automotive crash test system are much more difficult to meet than those of a data acquisition system used in a space environment. The high impact loads seen in an auto crash (sometimes in excess of 100g's at relatively long pulse duration) are usually not seen in space missions. To comply with the requirements it was necessary to put existing measurement hardware into a much more ruggedized housing. After two years of extensive development and testing, the first on-board crash test system was delivered and installed for vehicle crash testing. Kayser-Threde has since delivered a total of about 30000 on-board channels to the automotive industry worldwide.

The latest Kayser-Threde system is the MINIDAU®. The very small and compact crash recorder is available in a 32 and a 96-channel version. Since the product introduction in 1997, a total of 8000 data channels have been ordered from customers worldwide (including USA, Canada, UK, France, Sweden, Germany, Spain, Austria, India, Malaysia, Japan, Korea, and Australia). Then in April 1998 a 32-channel box was ordered by the European Space Agency… but certainly not for an automotive application!

Currently, many nations are working together on a gigantic space project, The International Space Station. The ISS will be the largest space object ever built. In order to ensure the safety of its crew, the ISS requires a permanent capability to return its crewmembers to the ground for various contingency situations. The Russian Soyuz will provide this capability during the initial stages of the Space Station program. Once the ISS is fully assembled in 2003, this need will be fulfilled by a combination of the Soyuz and the Lifting Body Crew Return Vehicle (CRV). The NASA program to design and to develop the CRV is called X-38 and will involve the construction of four demonstration vehicles. Three demonstration vehicles (V-131, V-132, and V-133) are going to be used from 1998 to 2000 for atmospheric flights. The X-38 design uses a lifting body concept originally developed by the Air Force's X-24A project in the mid 1970's. After the re-entry engine module is jettisoned, the X-38 would glide from orbit, unpowered like the Space Shuttle. It would then use a steerable parafoil, a parachute technology recently developed by the U.S. Army, for its descent to landing. The X-38 finally comes to rest on landing skids rather than wheels. The first X-38 atmospheric test vehicle V131 was dropped from under the wing of a NASA B-52 aircraft at the Dryden Flight Research Center, Edwards AFB, California on March 12, 1998 and completed a descent from a 23,000 foot altitude. Late in 2001 vehicle V-201 (the fourth atmospheric test vehicle) will perform an orbital flight that will conclude the X-38 project and allow the transition towards the CRV program. The V201 will be launched from Kennedy Space Center by the Space Shuttle on a low Earth orbit. After two days of activation and checkout, the V-201 will be deployed by the Shuttle and released. As the V201 is descending, a drogue will deploy at Mach 0.6, at an altitude of 6900 m. The parafoil is deployed at an altitude of 4500 m. The vehicle will then deploy the landing gear prior to touch-down at the landing site at Coober Pedy, in Australia.

The question remains, "Why will they need a Crash Test System?" Based on its experimental objective the V201 will be equipped with the large number (960) physical measurement sensors (e.g. thermocouples, accelerometers, strain gauges, acoustic microphones and a lot more). The sensors will be mounted at various positions across the body shape and also inside of the vehicle. The sensor data will be acquired continuously during all phases of the V201 mission. A Vehicle Analysis Data Recording System (VADR) will be responsible for managing the sensor data acquisition for all 960 sensors (see picture 2). As a participant in the VADR project, Kayser-Threde will be responsible for the central data acquisition system (also called DHS). This data acquisition system, however, has nothing to do with the crash test recording module that was requested by the ESA.

This means, we still have no answer to our question: Why have they requested a system originally designed for automotive crash testing? One of the experimental objectives of the V201 mission is to estimate the acceleration loads acting on a crewmember during the touchdown procedure. For this reason the V201 will be equipped with a CRV compatible crew seat occupied with a Hybrid III Crash Test Dummy. This anthropomorphic test dummy will be equipped with accelerometer sensors mounted internally in the dummy in the same configuration as for use in car crash testing. Triaxial sensors will be placed in the head, the upper neck, the thorax and the pelvis to measure the motion of the dummy crewmember during the descent and landing of the V201. The miniaturized crash test system MINIDAU® will be used to acquire the dynamic data that will be used by the project engineers to help determine the forces that will act on crewmembers descending in the actual Crew Return Vehicles.

MINIDAU® has been particularly designed for crash testing in the automotive industry. Its main features include:

32 analog sensor channels. Each channel has its own A/D converter with 16 bit resolution.

Recording time up to 100 s (@ 10 kHz)

Sampling rates from 100 Hz to 20 kHz

Internal memory capacity of 64 MB

The data acquisition of the MINIDAU® can be triggered by a single event; such as the beginning of a crash or the detection of any sensor signal above a threshold level, or it can be software triggered, which will be the preferred method during the mission. About one hour before landing, the MINIDAU® will be switched on to make sure that the system and all sensors are in stable temperature conditions. Several seconds before touchdown, the MINIDAU® will receive a trigger command from the X-38 ICP (Instrumentation Control Processor) that will signal the system to record data for about 100 seconds. The data will be stored in the MINIDAU® using Flash EEPROM to make sure that no critical information is lost even in the event of a power failure. After the vehicle has landed safely in Australia, the data from the MINIDAU® will be downloaded to a notebook computer for later analysis.

The engineers at Kayser-Threde are very proud that their MINIDAU®, developed for the automotive industry, has been selected for use in a major space program without major modification. Everybody is looking forward to the "Crash Testing in Space".