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Previous chapter: Development of the Spektr-R observatory
The Spektr-R spacecraft was expected to climb into orbit on July 18, 2011, according to a following flight profile (Moscow Summer Time):
The primary goal of the Spektr-R mission was to study structure and dynamics of radio sources inside and outside of our Milky Way galaxy. This research was expected to help in the understanding of fundamental problems of astrophysics and cosmology, including the structure of galaxies, star formations, black holes, dark matter and interstellar space. (485)
By placing a radio telescope into space it would be possible in conjunction with ground-based antennas to form the so-called a Very Large Array, essentially a gigantic virtual telescope. Due to the long wavelengths of radio waves, the reflectors of radio telescopes must be very large to focus the waves at a good resolution. It is especially important for pinpointing sources hidden deep in the Universe. A network of space-based and ground based telescopes could act as a single giant collector larger than Earth itself, reaching unprecedented signal clarity. It was expected that ground telescopes in Australia, Chile, China, Europe, India, Japan, Korea, Mexico, Russia, South Africa, Ukraine and USA would join the Radioastron spacecraft in observations employing a technique known as Very Long Baseline Interferometry, or VLBI. The satellite's main 10-meter radio telescope would be working in four different bands of radio waves. (484) It can "hear" sources at two frequencies simultaneously.
A secondary BMSV instrument was also planned for installation onboard Spektr-R within the Plazma-F experiment, which aimed to measure the directions and intensity of the solar wind. (481) On May 25, 2011, a garbled report by the RIA Novosti news agency appeared to confirm that the BMSV instrument would be onboard.
Immediately after the launch of Spektr-R on July 18, 2011, it was reported that the observatory had also carried a German-made micrometeoroid counter.
Soon after its launch on the Zenit rocket, the Fregat upper stage was expected to boost Radioastron into a highly elliptical orbit. At its closest point (perigee) the satellite would be passing 500 kilometers above the Earth surface and then would climb as far as 340,000 kilometers away from Earth in the apogee of its orbit. Such parameters would guarantee that the satellite would remain in operational orbit for at least nine years and it would never be in the shadow of the Earth for more than two hours.
With its apogee as far as the orbit of the Moon, Spektr-R would be in many respects a deep-space mission for Russian flight controllers. Due to the gravitational pull of the Moon, the satellite's orbit was expected to drift back and forth in three-year cycles, with an apogee fluctuating between 265,000 and 360,000 kilometers away from Earth and a perigee between 400 and 65,000 kilometers. It would take Radioastron from eight to nine days to complete each loop around the Earth. (484) Such a drift would greatly expand the telescope's field of view. It was estimated that up to 80 percent of the antenna's potential targets would be within "view" of the mission at one point or the other. (485)
The spacecraft was scheduled to spend its first 45 days in orbit going through so-called engineering commissioning, including the deployment of the main antenna, various systems checks and communications tests.
It would be followed by the scientific commissioning tests, involving major ground telescopes. Project managers hope that the first scientific information from the spacecraft would come during this period. For the next three to six months, initial scientific observations would be conducted. If everything went as planned, a routine scientific program would commence next. It was expected that at least seven days during each eight-day orbit completed by the satellite would be dedicated to scientific observations.
The spacecraft was expected to be operational for at least five years. The main limiting factor for the life span of onboard systems would be damaging effect of radiation affecting the spacecraft during the crossing of the Earth's radiation belt. In the meantime, it was forecasted that the Spektr-R's orbit would decay for around nine years, concluding with the reentry and destruction of the inactive observatory in the Earth's atmosphere.
International development team
In Russia, the Astro-Space Center of the Lebedev Physics Institute, FIAN, within the Russian Academy of Sciences took the leadership of the wide international team of scientists participating in the Spektr-R project. FIAN has led radio astronomy studies in the USSR since the dawn of the space era. (485)
The finalized scientific payload onboard Spektr-R carried radio receivers developed in India and Australia. According to the original plans, two other receivers for the spacecraft were to be supplied by European firms under a contract with the European VLBI Consortium (EVN). However despite being extensively tested as late as 2004 at the Pushchino radio telescope complex, these payloads had to be dropped from the mission due to their old age. They were eventually replaced by similar Russian instruments, which benefited from the development of the western predecessors.
To assist the development of the Spektr-R, the European Space Agency, ESA, conducted complex mechanical tests of Radioastron's giant antenna petals at its vacuum chamber facility in Noordwijk, Netherlands. ESA also paid for the super-accurate Rubidium frequency clock, developed by Neuchatel Astronomical Observatory in Switzerland, which was to be installed onboard Spektr-R.
The main responsibility for tracking of the Spektr-R mission was given to the 22-meter RT-22 radio telescope in Pushchino, Russia. Ground stations in Medvezhi Ozera (Bear Lake) near Moscow and Ussuriysk station in the Russian Far East would be responsible for the flight control of the mission. Ground telescopes in Arecibo, Badary, Effelsberg, GBT, Medicina, Noto, Svetloe, Zelenchukskaya were expected to be involved in joint observations with Spektr-R.
Next chapter: Design of the Spektr-R spacecraft
Page author: Anatoly Zak; Last update: August 1, 2011
Page editor: Alain Chabot; Last edit: June 6, 2011
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The Spektr-R spacecraft was designed to work in tandem with ground-based antennas forming a giant virtual radio telescope. Credit: FIAN