The South African National Space Agency (Sansa) and its Russian counterpart, Roscosmos, are continuing talks on possible future cooperation across a wide spectrum of space activities. In particular, a comprehensive cooperation agreement, that will include Sansa joining the Radioastron space radio telescope programme, is being drawn up.
Other negotiations are in their preliminary stages. One area for possible future cooperation is the development of space platforms, especially satellites. Related to this, but what is recognised to be a development – should it ever happen – for the long term, would be cooperation in developing a South African satellite launch capability.
The Radioastron mission is led by the Astro Space Centre of the Lebedev Physical Institute of the Russian Academy of Sciences. The other participants in the programme are Australia’s Commonwealth Scientific and Industrial Research Organisation, the European Space Agency, Finland’s Helsinki University of Technology, India’s Tata Institute for Fundamental Research and the US’s National Radio Astronomy Observatory. The Radioastron spacecraft was launched in 2011 and is equipped with a 10-m-diameter radio telescope dish. With a mass of 3.8 t, Radioastron is the biggest radio telescope in space. It has a highly elliptical orbit, with a perigee (point closest to the earth) of about 10 000 km and an apogee (point furthest from earth) of some 350 000 km, which takes it almost as far as the moon (the Moon’s average distance from earth is 384 400 km). It takes eight days and seven hours to execute one orbit of the earth.
Radioastron’s radio telescope is operated in conjunction with ground-based radio telescopes in a space very long baseline inter- ferometry (VLBI) programme that focuses on the centimetre and decimetre wavelength bands. Interferometry is the use of several radio telescopes in different locations to simultaneously focus on and image the same object in the sky. The signals received by each dish are fed into a computer and because the dishes are not in exactly the same place, the distance travelled by the signals to each is not identical and combining them creates an interference pattern that can be analysed by computer to provide high-resolution images of celestial objects. The baseline is the distance between the telescopes. With space VLBI, a space telescope is connected with terrestrial instruments to create huge baselines.
However, Radioastron is not the only space telescope programme that will be covered by the comprehensive space cooperation agreement now being drawn up. The agreement would also allow Sansa to join Roscosmos’s latest such project, Millimetron. This is also being led by the Astro Space Centre of the Lebedev Physical Institute, with Dutch involvement. A memorandum of understanding on Millimetron was signed between Roscosmos and the Netherlands Institute for Space Research (Sron) in January 2007. The first workshop on the project was held in 2009 in the Netherlands.
Millimetron is an approved Roscosmos mission with approved funding and it is hoped that it will be launched some time from 2019 to 2022, with the preference being sooner rather than later.
Sron describes Millimetron as “a space observatory operating in millimetre, submillimetre and far infrared wavelength ranges using a 12 m cryogenic telescope in a single-dish mode and as an interferometer with the space-ground and space-space baselines (the later after the launch of the second identical space telescope). The observatory will provide the possibility to conduct astronomical observations with super high sensitivity (down to nanoJansky level) in a single dish mode, and observations with super high angular resolution in an inter- ferometric mode.”
The term ‘cyrogenic’ refers to the design requirement that the telescope be cooled to an ambient temperature of less than 50 ˚K (or –223 ˚C). The Jansky is a unit used in radio astronomy, named after US radio astronomy pioneer Karl Jansky (1905–1050). It is a unit of radio flux density used for natural continuum emissions and 1 Jansky = 10-26 Watts/m2/Hertz, where the Hertz term refers to the detector bandwidth of the radio telescope.