Impact sensing systems and estimated impact rates of the upcoming meteoroid and space debris detector experiment (MDD3) onboard Russian Spektr-R satellite

MDD3 is a Meteoroid and Space Debris Detector experiment, which will be flown onboard Russian Spektr-R satellite with a planned launch for end of 2009. The MDD3 flight experiment has two goals: First, the on-orbit verification of the impact-detector technology and second, the monitoring of hypervelocity impacts from space debris and meteoroids on the ca. 0.12 m2 surface area of the detector. The detector has three different impact sensing systems that monitor different physical parameters of the impact: (1) ultrasonic transducers for monitoring the acoustic emission from the impact in the detector plate, (2) optical detectors for monitoring the light that is emitted from the impact plasma, and (3) a radiofrequency (RF) coil that is monitoring the transient magnetic field radiated from the impact plasma. A hypervelocity impact event will be assumed to have occurred if all three detection systems are triggered synchronously. The special character of the Spektr-R mission is that the satellite is operated in a highly elliptical orbit, which encounters the Earth orbit environment from 600 km perigee altitude up to 330000 km apogee altitude. Hence, MDD3 allows for in-situ measurement of space debris and micro-meteoroid impacts in various Earth orbit particle environments, which has never been done before. This paper gives an overview of the Spektr-R mission, describes the impact sensing system of the MDD3 and provides a first estimate of the predicted impact rates of the MDD3 during one orbit of Spektr-R based on meteoroid and debris flux model calculations.