December 2012 - URSI

Figure 2. A schematic diagram of the RadioAstron Space Radio Observatory, showing the location of the navigator
service bus, the hydrogen maser frequency standards, the high-gain communications antenna (HGCA), and other
subsystems. The solar panels are oriented orthogonally to the diagram.
X-Gamma and Spectrum-UV, to operate at X/γ-ray and
ultraviolet wavelengths, respectively. However, the
challenging technical goals of the three missions, combined
with the political and economic difficulties following the
fall of the Soviet Union, resulted in lengthy delays in the
Frequency
(GHz)
Ts
(K)
(μarcsec)
0.33 200 530 46
1.66 45 100 5
4.6 130 35 6
22 77 7 20
(mJy)
Table 1. The main characteristics of the
four RadioAstron frequency bands.
completion of RadioAstron. It was later transferred to the
Astro Space Center (ASC) of the P. N. Lebedev Physical
Institute of the Russian Academy of Science. Spectrum-X-
Gamma and Spectrum-UV are currently under construction:
the launch of the former is planned for 2014. The locations
of the major substructures are illustrated by the schematic
diagram of the spacecraft shown in Figure 2. The assembled
dish structure is shown in Figure 3, as seen by the visit of
the RadioAstron International Steering Committee in 2008.
After 30 years of development of this ambitious
space VLBI project by scientists and engineers at the ASC,
the 3660 kg RadioAstron spacecraft was finally launched
from the Baikonour Cosmodrome on July 18, 2011. A day
later, it was placed in a highly elliptical orbit, extending
out beyond 300,000 km, with an eight-to ten-day period.
24 The Radio Science Bulletin No 343 (December 2012)