Spektr-R ( Radio-Astron)

Spacecraft n°:

Multinational spacecraft n°:

Launch data: Designation  37755 / 11037A Launch date  18 Jul 2011 - 02:31 UT Launch site  Baik, LC-45/1 Launch vehicle  Zenit-3F/Fregat Mission  Government: Astronomy, X-Ray, Gamma Elliptical Earth orbit: Perigee / Apogee  1000 x 330000 km Eccentricity  9.57E-01 Inclination  51.46 deg Period  8 days

Spacecraft data:

Description:

• The Spektr-R (formerly RadioAstron) project is an international collaborative mission to launch a free flying satellite carrying a 10-meter radio telescope in high apogee orbit around the Earth. The aim of the mission is to use the space telescope to conduct interferometer observations in conjunction with the global ground radio telescope network in order to obtain images, coordinates, motions and evolution of angular structure of different radio emitting objects in the Universe with the extraordinary high angular resolution.
• Spektr-R, also known as RadioAstron, is a 3660 kg spacecraft based on the Lavochkin company's Navigator bus, and carries a 10m diameter radio telescope observing at 92, 18, 6 and 1.35 cm wavelengths. The satellite also carries solar wind and cosmic dust detectors, and laser corner reflectors for tracking.
• Featuring a 30-foot (10-meter) wide antenna, "The aim is to use the space telescope to conduct interferometer observations to obtain images, coordinates, motions and evolution of angular structure of different radio emitting objects in the universe."
• The Project has a number of scientific objectives:
  • studying galaxies and quasars in the radio band;
  • studying the structure and dynamics of regions around black holes;
  • studying black holes and neutron stars in our galaxy;
  • measuring distances and speeds of pulsars and other galactic sources;
  • studying the structure of interstellar plasma;
  • determining fundamental cosmological parameters;
  • producing a highly accurate coordinate system;
  • producing a highly detailed map of Earth’s gravity field.

Mission details:

• The Zenit-3F/Fregat rocket entered a 177 x 447 km x 51.4 deg orbit; four small separation motor covers were jettisoned to 175 x 660 km. The first Fregat upper stage burn put it in a 429 x 3703 km orbit. The Fregat's SBB (Sbrasivaemiye baki banov) drop tank was jettisoned into this orbit prior to a second burn which boosted the orbit to 1045 x 332728 km x 51.6 deg. RadioAstron separated from Fregat at 0606 UTC and reached first apogee around Jul 21.
• After an initial partially successful attempt on Jul 22, 2011 the RadioAstron antenna was successfully unfurled and locked in place on Jul 23. Spektr-R's orbit on Jul 25 was 1248 x 334727 km x 51.83 deg, stretching nearly to lunar distance.

Space-based radio astronomy:

• Space-based radio astronomy using very long baseline interferometry (VLBI) in the GHz band began with the Soviet KRT-10 experiment in 1979. Launched on the Progress-7 cargo ship, the 10 m dish was deployed in low orbit on the Salyut-7 space station and used for observations at 0.4 and 2.5 GHz. A 4.9m dish on NASA's TDRS 1 communications satellite was used for demonstration experiments at 2.3 and 16 GHz in 1986-1988 in geostationary orbit at 35800 km. The VSOP experiment on the Japanese HALCA satellite, an 8-m dish observing at 1.6 to 22 GHz, operated from 1997 to 2003 with an apogee of 21000 km. Space VLBI involves combining the space-based antenna with a ground-based one to simulate a single antenna with a diameter equal to the distance between the components; the higher the apogee of the space-based antenna, the higher the spatial resolution achievable by the observations.
• The RadioAstron experiment, led by Kardashev at the Lebedev Institute, has an orbit an order of magnitude higher than previous experiments and thus should deliver record resolution.
• Higher frequency studies in the 100-1000 GHz range (sometimes called radio astronomy but more frequently `submillimeter astronomy') have mostly focussed on the cosmic microwave backround radiation with suborbital experiments (by Gush in Canada, 1971-1990 on Black Brant rockets; Houck at Cornell on Aerobee 4.177 and 4.178 in 1968; Blair from Los Alamos on a Sandia rocket in 1972, Matsumoto and Lange on K-9M-78 and K-9M-80 in 1985-87, and Mastumoto's S-520-17 experiment in 1995) followed by orbital experiments (Prognoz-9/Relikt, 1983; COBE, 1989; WMAP, 2001; Planck, 2009). In addition, the SWAS and Odin satellites (1998, 2001) have studied galactic submillimeter emission and ESA's Herschel also overlaps the range.
• Space-based low frequency radio astronomy in the 0.5-15 MHz frequency range has a long history beginning with the Blue Scout D-3 suborbital flight in Jan 1961 as part of the Harvard Space Radio Project, which continued with orbital flights on CORONA missions 26, 29, 31, 42, 43, 44 and 46 and MIDAS missions 6 and 7, as well as the AD-622 suborbital probe. The Gorkiy radiophysical institute flew instruments on Elektron 2 and 4, Kosmos-119, 142 and 259. F. Graham Smith (MRAO/Jodrell) flew experiments on the UK's Ariel 2 and 3; Canada's DRTE lab deployed 73-meter antennas on the Alouette and Isis satellites. The Meudon group flew 36-m dipoles on Rubis rockets in 1965 and 1967.
• The University of Michigan experiments on OGO 1 to 4 studied solar radio bursts; these were preceded by test flights on suborbital Journeyman 11.02UR and 11.03UR flights in 1962-1965. Experiments were also flown by ISAS (Shinsei, 1971), Iowa (IMP 8, 1973), the Warsaw Aviation Inst. (IK-Kopernikus-500, 1973), and the French amateur organization ESIE (SARA, 1991). The most ambitious experiments in this frequency range, however, were done by Joe Alexander, RG Stone et al. at NASA-Goddard, beginning with Javelin and Astrobee 1500 sounding rocket flights (8.33GR, 8.44GR, 16.03GR, 16.06GR) and continuing in orbit with the 91-meter dipole on ATS 2 (1967) and IMP 6 (1971) and the 229-meter V-dipoles on RAE 1 (1968) and RAE 2 (in lunar orbit, 1973). These low frequency experiments mostly detected diffuse galactic emission and ionospheric and solar activity.