The PIA data was acquired in four modes of data compression, termed mode 0 (the least compressed), and modes 1, 2, and 3, each with increasing degrees of compression. With each spectrum are a PIA assigned sequence number and event numbers, a unique ID-number, instrument settings, and the relative approach time. The PIA time is a 16-bit counter that starts with zero after switch-on. As the Spacecraft Time Signal (STS) is used to reset the internal PIA time counter, the TIM highest possible value is 48960 counts. STS-pulses are given after the transimssion of 256 formats. This results for format F1/F2 and high bitrate (46080 bps) in 5802.67 s. (= 256 formats * 64 frames * 2040 bytes * 8 bit/byte/46080 bps) The time resolution is DTIM = 1/ (138240 HZ /2**14 ) = 0.1185 s. Each STS defines the time for an event with TIM = 0. Therefore, SCET = GRT(STS) + (TIM * DTIM) - propogation delay (8:00.1 sec). where SCET = Spacecraft Event Time, GRT = Ground Reception Time.

Dust Impact Detection System (DIDSY) consists of six independent subsystems with the primary aim of registering the impacts of all particulates of significant mass incident on the probe during the post-perihelion encounter with Comet Halley in 1986. Mounted on Giotto's front dust shield, the detectors will determine the mass spectrum of the dust, with a limiting sensitivity of some 10^^-17^^ g, increasing to the largest grain masses encountered along Giotto's trajectory through the cometary environment with an ultimate spatial resolution of some 70 km. An additional detector is located on the rear shield to monitor those dust particles (m > ~ 5 X 10^^-7^^ g) that are able to penetrate the front dust shield. An ambient plasma monitor is also incorporated into DIDSY to measure the inJpact plasma generated by both dust and gas impacts on the spacecraft. The system is controlled and its data processed by a microprocessor-based system that allows the wide range of anticipated impact rates (varying from a few per minute, to ~ 10^6 s^^-1^^ at closest approach) to be handled. The instrument weighs 2.26 kg and consumes 1.9 W of power during normal operation.

Dust Impact Detection System (DIDSY) consists of six independent subsystems with the primary aim of registering the impacts of all particulates of significant mass incident on the probe during the post-perihelion encounter with Comet Halley in 1986. Mounted on Giotto's front dust shield, the detectors will determine the mass spectrum of the dust, with a limiting sensitivity of some 10^^-17^^ g, increasing to the largest grain masses encountered along Giotto's trajectory through the cometary environment with an ultimate spatial resolution of some 70 km. An additional detector is located on the rear shield to monitor those dust particles (m > ~ 5 X 10^^-7^^ g) that are able to penetrate the front dust shield. An ambient plasma monitor is also incorporated into DIDSY to measure the inJpact plasma generated by both dust and gas impacts on the spacecraft. The system is controlled and its data processed by a microprocessor-based system that allows the wide range of anticipated impact rates (varying from a few per minute, to ~ 10^6 s^^-1^^ at closest approach) to be handled. The instrument weighs 2.26 kg and consumes 1.9 W of power during normal operation.

This dataset contains the results obtained from the Dust Impact Detection System (DIDSY) flown aboard the GIOTTO spacecraft during its extended mission to Comet P/Grigg-Skjellerup in 1992. The measurements and analysis of the three impacts detected during close approach are contained in text files. Calibration tables for the sensors are included in this dataset. These data have not been reviewed or formally archived with the PDS.

This dataset contains the results obtained from the Dust Impact Detection System (DIDSY) flown aboard the GIOTTO spacecraft during its extended mission to Comet P/Grigg-Skjellerup in 1992. The measurements and analysis of the three impacts detected during close approach are contained in text files. Calibration tables for the sensors are included in this dataset. These data have not been reviewed or formally archived with the PDS.

The data from MPI for this dataset were received as text files each containing spectra of a single instrument mode (there were several files for most modes). These spectra were reformatted into binary tables, and all spectra from each mode were combined into a single file. The original order of the spectra has been preserved. Spacecraft time, relative to switch-on of the instrument is specified as 1 clock tick = 0.11852 seconds. The exact equation is:

The data from MPI for this dataset were received as text files each containing spectra of a single instrument mode (there were several files for most modes). These spectra were reformatted into binary tables, and all spectra from each mode were combined into a single file. The original order of the spectra has been preserved. Spacecraft time, relative to switch-on of the instrument is specified as 1 clock tick = 0.11852 seconds. The exact equation is:

Derived, calibrated density profiles from the NMS ION and NEUTRAL sensors flown on the GIOTTO mission and obtained during the comet Halley fly-by on 13 March 1986. This data set corrects issues found in the GIO-C-NMS-4-86P-V1.0 data set.

The data from MPI for this dataset were received as text files each containing spectra of a single instrument mode (there were several files for most modes). These spectra were reformatted into binary tables, and all spectra from each mode were combined into a single file. The original order of the spectra has been preserved. Spacecraft time, relative to switch-on of the instrument is specified as 1 clock tick = 0.11852 seconds. The exact equation is:

The data from MPI for this dataset were received as text files each containing spectra of a single instrument mode (there were several files for most modes). These spectra were reformatted into binary tables, and all spectra from each mode were combined into a single file. The original order of the spectra has been preserved. Spacecraft time, relative to switch-on of the instrument is specified as 1 clock tick = 0.11852 seconds. The exact equation is: