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We consider a new design of a high-precision three-axial sensor of angular velocities whose sensitive elements are fiber optic gyroscopes using the Sagnac effect. The instrument is designed for measuring the rotation velocity of an orbiting spacecraft (microsatellite) and for performing its attitude control.

A quartz sensor of small accelerations with a capacitive transducer is designed and produced, allowing one to measure spacecraft accelerations with a resolution of 10–7 m/s2 in the range ±10–1 m/s2. The results of calibration of the sensor by the method of inclinations are presented.

A gas-discharge anemometer is designed for investigating the gas-flow dynamics in wind tunnels, and in experimental and space meteorology. The anemometer allows one to measure simultaneously the magnitude and direction of the gas-flow velocity vector and the gas pressure in the flow. The instrument consists of a gas-discharge chamber, an analyzer of scattered ions, a power supply unit, and a measuring unit. The anemometer weight does not exceed 0.1 kg, and the power consumption does not exceed 0.2 W. The instrument was put through preliminary tests in a wind tunnel that simulated, in particular, the conditions in the boundary layer of the Martian atmosphere and produced a directed gas (air or CO2) flow whose velocity could be varied from 0.5 to 50 m/s at pressures from 0.3 to 1.3 kPa and temperatures from –120 to +20°C. The anemometer sensitivity is no worse than 100 mV/(m/s). The method of calculating the gas-flow velocity on the basis of the measured ion-current distributions is developed.

An analysis of the spectra from the PUMA dust-impact mass spectrometers onboard the Vega-1 and Vega-2 spacecraft shows that a large number of the observed, unidentified small-amplitude peaks are produced by impacts of very-low-mass (from 10−17 to 10−20 g) particles. The mass flux of very fine particles accounts for a few percent of the total dust mass flux from comet Halley. The elemental composition of the finest cometary particles is identical to the composition of large particles (10−12–10−16 g), in agreement with present views about the nucleus of comet Halley as an aggregate of interstellar dust.

Dust-impact PUMA mass-analysers aboard the spacecrafts VEGA-1 and VEGA-2 allow to conduct the first direct measurements of mass spectra of comet Halley’s dust envelope particles with masses higher than 10 -17 g [1,2]. The analysis of spectra measured by the PUMA instruments showed that unindentified peaks in this spectra could be associated with very small particles (mass 10-17–10-20 g).

Measurements of the element composition of the dust particles in Comet Halley were made by the PUMA-1 and PUMA-2 instruments onboard the VEGA spacecraft. The timeof-flight analysis of ions produced by the hypervelocity particle impact on the target was applied with a wide (W = 100 eV) and a narrow (W = 20 eV) energy window of the instruments. The analysis of measured spectra shows that the mass resolution for “small” particles (Q < 10−13 C) was high enough in both modes to separate individual mass lines. For large particles the resolution did not change for the narrow window, it decreased, however, for the wide one (to about 50). A relative transmission Q W /Q n dependence on the mass number for the wide and narrow window made has been found.

Mass spectra of cometary dust particles measured by the PIA dust particle analyzer aboard the Giotto spacecraft show some unexpected and striking features. First, small particles below 10 to the -14th g are much more abundant than anticipated by models. Second, most of the particles are rich in light elements such as H, C, N, and O, suggesting the validity of models that describe the cometary dust as including organic material. Third, the light elements specifically seem to have a low ratio of mass to volume. Three examples of original mass spectra showing typical compositions are given; these have been measured, and are compared with a computer-simulated mass spectrum.