Mission Overview

UK 6 was the sixth and last satellite in the Ariel series. This satellite was launched on June 3, 1979, into a near-circular 625-km, 55-deg inclination orbit. The objective of this mission was to undertake studies in high-energy astrophysics. Two X-ray experiments, one cosmic-ray experiment, and three technology experiments were carried. The spacecraft was spin stabilized, with the spin axis commanded into a sequence of orientations to accommodate the X-ray experiment requirements.

Launch Date: 1979-06-02 at 23:26:00 UTC
Launch Vehicle: Scout
Launch Site: Wallops Island, United States
Decay Date: 1990-09-23

Trajectory Details
Type: Orbiter
Central Body: Earth
Epoch start: 1979-06-02 00:00:00 UTC

Orbital Parameters
Periapsis 605.0 km
Apoapsis 651.0 km
Period 97.30000305175781 minutes
Inclination 55.0°
Eccentricity 0.003281000070273876


Cosmic Ray

The instrument consisted of 4-pi Cerenkov and gas scintillation counters with a geometric factor of 2 sq m-sr. These were used to measure the charge and energy spectra of the ultraheavy component of cosmic radiation with particular emphasis on the charge region Z›=30.

X-Ray Proportional Counter Spectrometer

The instrument consisted of an array of xenon-filled proportional counters designed for detailed measurement of time variability and spectra of both galactic and extragalactic sources. The detector array was sensitive over the energy range 1.2 to 50 keV and viewed along the spacecraft spin axis through 3-deg FWHM field collimators. Bright X-ray sources could be measured to several microseconds time resolution, and spectral data were obtained in 32 channels.

X-Ray Grazing Incidence System

This system consisted of four grazing-incidence hyperboloid mirrors that reflected X-rays through an aperture/filter to four continuous-flow propane gas detectors covered with a 1-micrometer polypropylene window. The instrument was sensitive to X-rays from 0.1 to 2 keV and had seven selectable FOVs from 0.2 to 3.6 deg. The system could be operated in four different modes: spectral (32 channels of pulse height), time (0.5 ms to 16 s), pulsar (periods from 8 ms to 4 h), and autocorrelator (periodic variations from 128 ms to 2 s). The detectors pointed along the spacecraft spin axis.