EUROPEAN TECHNOLOGY EXPOSURE FACILITY-DEBRIS IN ORBIT EVALUATOR-2 (EUTEF-DEBIE-
- Research Area: Technology Demonstration - Space Debris and Micrometeoroids
Measurement
Expedition(s): 16- 20
Principal Investigator(s): ● Gerhard Drolshagen, PhD, European Space Research and
Technology Centre, Noordwijk, Netherlands
RESEARCH OBJECTIVES
The European Technology Exposure Facility-DEBris In Orbit Evaluator-2 (EuTEF-DEBIE-
2) actively measures impact flux of sub-millimetre micro-meteoroids and space debris
hitting its 3 sensor units oriented in different directions and thus provides an insight
into this smaller type of orbital debris of which little is known. Knowledge of impacts,
their seasonal variations, and long-term evolution are required for a reliable spacecraft
risk assessment and the design of protective shielding.
RESULTS
DEBIE-2 data was highly dominated by noise events following a
first analysis of potential impact events, with false events
mainly being due to the International Space Station (ISS)
plasma and thermal environment and ISS operations (eg,
shuttle docking/undocking). After initial background noise
filtering was undertaken, 931 events were identified as
potential impact events in the period January-September 2009.
From this data a significantly higher amount of impacts
occurred on the upward (zenith)-facing sensor than on the
forward-facing and starboard sensors.
One of the surprising findings was that impact events came in
clusters and were not randomly distributed. These peaks can
be concentrated within the space of perhaps a minute to 80
seconds at a time, indicating the existence of dust clouds
along the ISS orbit. These particles might be either natural or
artificial in origin. Asteroids and comets leave trails of fine dust
behind them while solid rocket boosters spray out fine
droplets of aluminium oxide.
After retrieval of DEBIE-2, it was found that one wire of the upper grid on the sensor unit
pointing to the zenith had been broken while in orbit. A postflight analysis was started including
the use of optical microscopy. Hundreds of holes were observed in the area beneath the broken
wire, indicating that the particle was vaporised during the impact. Since the impacted wire had
a diameter of 75 μm, one can derive that the impactor should have had a minimum size of 25
μm and a maximum size of about 50 μm, otherwise it should have survived the impact.
DEBris In Orbit Evaluator- 2
instrument on the external surface
of the Columbus laboratory as part
of the European Technology
Exposure Facility. ESA image.