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 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.

A wide range of ion species and velocity distributions are expected to be found as the Giotto spacecraft traverses the coma of Halley's Comet. The outer coma is characterized by the interaction between solar wind and cometary plasmas, the inner coma by the outflow of cometary neutrals and their ionization products. The resultant demands on instrument dynamic range preclude use of a single sensor for measurements of ion composition. The Giotto Ion Mass Spectrometer (IMS) therefore consists of two sensors: one optimized for the outer and the other for the inner coma, with each obtaining complementary information in the region for which it is not optimized. Both sensors feature mass imaging characteristics, thereby permitting simultaneous measurements of several ion species by means of multi-detector arrays. The High Intensity Spectrometer (HIS) was designed to complement the HERS in the inner coma.

The main objective of the Giotto Magnetometer Experiment is the investigation of the interaction between Comet Halley and the solar wind at a distance of 0.9 AU from the Sun, to within 500 km of the cometary nucleus. A second objective is the study of the interplanetary magnetic field. The instrumentation consists of a triaxial and a separate biaxial system of fluxgate sensors of the ring-core type, the associated analogue electronics and a digital processor. The measuring ranges of +/- 16 nT, +/- 64 nT, etc., up to +/- 65536 nT are digitis- ed by a 12-bit analogue-to-digital converter, allowing a sampling rate of 28.24 vectors per second at encounter. Memory modes allow the bridging of gaps in telemetry coverage of up to ten days. The total mass of the instrument is 1360 g and its power consumption 820 mW.

The Giotto Radio Science Experiment data set consists of four tables. Each table contains a measurement value listed as a function of time. The measurements are: closed-loop receiver carrier signal amplitude, closed-loop receiver carrier frequency residual, open-loop receiver carrier signal amplitude, and open-loop receiver carrier frequency.

In total 2304 images were returned on encounter night between 20:54 and 00:03 UT. Of these images, a total of 2017 are present in the data set submitted to IHW.

The OPE photopolarimeter was designed to measure the polarized components of the light in seven bandpasses or channels, ranging from the near ultraviolet to the near infrared. Three channels (so- called blue, green and red) were devoted to the observation of the scattering of solar light by cometary dust grains, in emission-free countinuum bands. Four other channels (so called OH, CN, CO+, C2) were devoted to the observation of light emitted by cometary gases.

A wide range of ion species and velocity distributions are expected to be found as the Giotto spacecraft traverses the coma of Halley's Comet. The outer coma is characterized by the interaction between solar wind and cometary plasmas, the inner coma by the outflow of cometary neutrals and their ionization products. The resultant demands on instrument dynamic range preclude use of a single sensor for measurements of ion composition. The Giotto Ion Mass Spectrometer (IMS) therefore consists of two sensors: one optimized for the outer and the other for the inner coma, with each obtaining complementary information in the region for which it is not optimized. Both sensors feature mass imaging characteristics, thereby permitting simultaneous measurements of several ion species by means of multi-detector arrays. The prime objective of the High-Energy Range Spectrometer (HERS) is to measure the ion abundances and three-dimensional velocity distributions outside the cometary contact surface.

The Giotto Radio Science Original Experiment Data Set includes two types of data -- an Archival Tracking Data File (ATDF) from closed loop receivers and Original Data Records (ODRs) from open loop receivers.