Interplanetary dust is considerably credited for the formation and evolution of our solar system. It is even credited to have provide water for our planet which kick started life. The cosmic dust which predate our solar system is considered a key to information about processes at the end of the lifetime of ancient stars. It is therefore seen necessary to measure the special number density of dust particles larger than 10 mm in the interplanetary space between Earth and Venus with a higher time-space resolution than ever before. Consequently, in May 2010, the Arrayed Large-Area Dust Detectors in INterplanetary space (ALADDIN)- a polyvinylidene fluoride -based in-situ dust impact detector- onboard the IKAROS solar sail was launched for such a purpose. The resulting data from ALADDIN had to be screened and reduction procedures for the dust impact measurement performed.
Takayuki Hirai and colleagues proposed a study on the screening and reduction procedures for the raw data of the ALADDIN. They aimed at screening the data so as to identify the dust impact events from all the downlinked events and conduct reduction procedures so as to estimate physical parameters such as the mass of the impacted dust particles, for use in subsequent studies. Their work is published in Advances in Space Research.
First, the research team obtained downlinked data from the ALADDIN which had been collected over a period of 300 days. They then carried out data screening procedures so as to remove the non-impact events recorded over the duration stipulated. Multi-flagged events of the measured events were then validated. The authors of this paper then indulged in data reduction procedures which were based on the analog and digital characteristics of the ALADDIN electronics. Eventually, the researchers summarized the outcomes of the data screening and reduction procedures of the IKAROS-ALADDIN measurement data.
From all the recorded outcomes, the researchers identified 1773 events as the most promising dust impact events. They observed that the mass range of the impacted dust particles corresponded with that of the dynamic range of the analog peak amplitude. In addition, they also noted that the digital characteristics such as the slow signal-sampling rate, lead a probabilistic effect on the interpretation of the recorded download amplitude value.
The study indicated that despite the inadequacies of the ALADDIN equipment in detecting smaller particles due to sampling effect, it is still well suited to observe the distribution of dust particles which are larger than 10 mm in the Earth-Venus region. As for the data set with download amplitude value higher than 2V, nearly 100% are generated by dust particles larger than 10 mm.
Takayuki Hirai, Hajime Yano, Masayuki Fujii, Sunao Hasegawa, Nobuhiro Moriyama, Chisato Okamoto, Makoto Tanaka. Data screening and reduction in interplanetary dust measurement by IKAROS-ALADDIN. Advances in Space Research volume 59 (2017) pages 1450–1459.Go To Advances in Space Research