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Russian ultraviolet astronomy's long road to space

The Spektr-UF spacecraft was to become the third in a series of large orbital telescopes developed in the post-Soviet Russia. Also known as World Space Observatory Ultraviolet, WSO-UV, the satellite was designed to see the sky in ultraviolet and visible light. The same filtering effect of the atmosphere protecting life on Earth from harmful radiation also blocks the view of dramatic phenomena playing out in the Universe in most ranges of electromagnetic spectrum, including ultraviolet, or UV. As a result, since 1970s, the ultraviolet astronomical observations have been delegated to space observatories, orbiting the Earth beyond its atmosphere.

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The Spektr-UF space observatory in deployed (left) and launch configuration. Copyright © 2010 Anatoly Zak / Roskosmos

Astron-Spika project

Like many other civilian and scientific space applications, the orbital astronomy grew out of military technology. In 1972, the USSR began deployment of the top-secret satellite network, called US-K, intended for early warning about launches of ballistic missiles. The first spacecraft of that type, known as 5V95 or Oko, was launched on Sept. 19, 1972. Developed at NPO Lavochkin based in the town of Khimki near Moscow, the satellite carried an infra-red telescope. It was the first experience for NPO Lavochkin with the development and launch of a telescope-carrying satellite.

Coincidently, the first Oko lifted off less than a month after the launch of the American OAO-3 Copernicus observatory on Aug. 19, 1972. Among its instruments, the spacecraft carried the Kassagren telescope designed for capturing ultra-violet radiation and sporting a primary mirror with a diameter 81.3 centimeters, which constituted a major advance in orbital telescopes.

It made the chief engineer of the US-K satellite Anatoly Chesnokov thinking about an equally powerful Soviet telescope, which would match the capabilities of the Copernicus. Chesnokov initiated the study of an ultra-violet instrument called Spika with a 80-centimeter mirror.

Initially, Spika was intended for military observations of the Earth's surface from the US-KVI spacecraft developed at NPO Lavochkin, but Andrei Severny, the head of the Crimean Astrophysics Observatory, KrAO, which was subcontracted to design an optical system for Spika, also proposed to use the telescope for observations of stars.

Jointly, NPO Lavochkin and KrAO formulated requirements for the design of the telescope and its installation aboard the spacecraft.

NPO Lavochkin initially hoped to sub-contract the detailed design, manufacturing, testing and calibration of the Spika instrument to the most prolific Soviet organization in the field of telescope construction -- Leningrad Optical and Mechanical Association, LOMO. However, after styding the potential design, engineers at LOMO estimated the mass of the instrument at 1,300 kilograms, far beyond the 800-kilogram telescope aboard the American OAO-3 Copernicus satellite and, more importantly, beyond the limit imposed on Lavochkin. The company requested a second opinion at the State Institute for Applied Optics in the city of Kazan, whose verdict was much worse -- the 1,800-kilogram instrument.

As a result, NPO Lavochkin took over the development and manufacturing of the Spika telescope, while KrAO took on itself, the testing and calibration of the instrument. The resulting instrument ended up with a mass of just 400 kilograms and its capabilies exceeded that of its American predecessor. (867)

Severny and his colleagues A. Boyarchuk and L. Granitsky marshaled the Spika project through all stages of development, despite a skepticism of Vechaslav Kovtunenko, who was appointed the Chief Designer at NPO Lavochkin at the end of 1977. Kovtunenko stopped the work on the US-KVI and the orbital observatory with the Spika telescope.

At the time when spacecraft developers such as NPO Lavochkin would often trump plans of their clients in the scientific community, Severny resorted to writing a lobbying letter to the Central Committee of the Communist Party, essentially forcing Kovtunenko to comply.

On Dec. 8, 1978, the Academy of Sciences, AN USSR, and the Ministry of General Machine-building, MOM, which oversaw the rocket industry, issued a joint document entitled "Program of development of scientific means for 1981-1990," which mandated the work on several scientific spacecraft projects, including an astrophysics satellite with a Spika UV telescope.

However, instead of the original plan to base the observatory on the US-K early-warning satellite, it was decided to use upgraded hardware from a series of Mars probes, M-71, developed for the launch window in 1971, as a platform for the future spacecraft. A number of support systems aboard M-71 had already been upgraded for the goals of the radar cartographer of Venus, including a system for faster transmissions of commands aboard the spacecraft, larger solar panels, now reaching seven square meters, and the continuous signal transmitter, instead of an older impulse modulator.

Because, propellant tanks served as the structural core of the M-71 spacecraft, but would not be needed on the observatory lacking main KTDU engine, the tank structure was replaced with a cylidrical backbone, which now served as an interface between a skirt-shaped service module of the M-71 spacecraft and the new telescope module. Inside, the base cylinder containued a truss holding several pressurized gas tanks.

Several other sub-systems, such as attitude control system, also underwent minor modifications. The constant three-axis solar and celestial orientation system, PSZO, would be achieved with the help of a sun and a star sensors with an accuracy of only one degree. Special angular velocity sensors would be used to search for the sun and celestial objects used by the navigation system. Under solar orienation mode, known as RS mode, the spacecraft could maintain its attitude with an accuracy of 30 angular minutes.

On M-71 series, the orientation of the spacecraft during main engine firings would be conducted with the help of a gyroscopic platform. Before the transfer of control to the gyro-platform, the attitude control system would switch to the so-called AK mode, which probably stood for accelerometers. The AK mode had an accuracy up to five angular minutes. The AK orientation mode was made primary onboard the observatory, so it could pinpoint its targets. However the operation of instruments under RS and AK modes was limited to four hours and demanded high consumption of propellant.

To home-in on the astronomical target, the telescope would adjust the field of view of its solar and star sensors.

On the Soviet planetary spacecraft, star sensors most frequently used Canopus, and less frequently Sirius and Vega as primary navigation points. However, the orbital observatory needed more targets to improve navigation accuracy. To achieve that, the star trackers were upgraded, to allow the device to use up to 15 stars as navigational targets. They included such stars as Rigel, Betelgeise, Achernar, as well as prominent planets Jupiter, Saturn and Mars.

The attitude control system of the Astron spacecraft included jet nozzles with three thrust levels and using nitrogen gas. In the "on-duty" modes, with both solar and celestial orientation, nozzles operated at the low thrust. Under RS and AK modes, the attitude control system would switch to the midium or high thrust.

Like with any other spacecraft developed during the Soviet period, the Astron project was accompanied by a package of experimental works, Integrated Program for Development and Testing, KPEO, when required to build an array of test vehicles. In addition, contractors were expected to provide fully operational copies for most flight-worthy systems and components of the spacecraft in case of an irreversible damage during electric tests, in order to quickly replace them and meet launch windows especially for planetary spacecraft. Failed components would be sent to the manufacturer for repairs before their return to the prime contractor. After the launch of the spacecraft, backup components could easily became a basis for another spacecraft.

On May 8, 1980, Central Committee of the Communist Party and the Soviet of Minister issued a decree that approved the development of scientific space projects in the USSR during the period from 1981 to 1990. It called for two phases in the Soviet space-based astrophysics projects:

–During the first phase in 1982 and 1983, the 1A (astrophysics) spacecraft series would be launched based on existing spacecraft platforms developed for the Mars-71 (M-71) and 4th-generation Venus probes (4V).

-During the second phase, four more advanced astrophysics observatories would be launched under designation 2A in 1985, 1987, 1988 and 1989.

Astron enters orbit

On March 23, 1983, the USSR launched the first spacecraft in the 1A astrophysics series designated 1A No. 602. Publicly, it was announced as Astron.

Astron orbital observatory developed in cooperation with France. The missions main payload was the Spika telescope.

The Astron spacecraft ended up at the right place at the right time to watch spectacular Supernova 1987A. Unfortunately, scientific effectiveness of the Astron project was hampered by a very limited availability of a single ground receiving antenna in Yevpatoria on the Crimean Peninsula. As a result, the scientific return from the spacecraft was largely overshadowed by data from the Western IUE spacecraft, featuring a telescope half of a diameter of the Astron's. IUE was supported by a pair of ground antennas at Goddard Space Flight Center in the US and at Villa Franka in Spain. The data from the space observatory was stored in a centralized archive, which was much easier to access for scientists around the world than the information from the Soviet spacecraft. (611)

Astron-2 becomes Granat

The original government decree for the launch of 1A satellite also called for the construction and launch of a duplicate spacecraft 1A No. 603, which would carry another Spika telescope. However, it had never been built and the two existing copies of the Spika telescope were left at NPO Lavochkin and the Crimean Observatory.

One reason for the delay with the construction was a very successful operation of the first telescope, while the Russian-French agreement on the cooperation in the Astron project emphasized the launch of the second satellite in case of the failure of the original one.

However, even before the first Astron was launched, the French Space Agency, CNES, asked the USSR to launch a similar satellite, but carrying the gamma-ray telescope instead of the UV-instrument. CNES originally developed the gamma-ray instrument for the Sigma satellite, which was to be launched during the first test launch of the Ariane-4 rocket in an elliptical Earth's orbit with an apogee of 200,000 kilometers. However, due to funding problems, the development of the Sigma satellite was stopped in 1983.

The Soviet planners integrated the Sigma telescope into what became the Granat project, which also carried the Soviet-built ART-P and ART-S telescopes and survey detectors Konus, Febus and WOTCh.

Spektr-UF to follow Astron and Granat

When the Astron observatory ceased active operations in June 1989, Soviet scientists had conceived a much larger UV-telescope christened Spektr-UF, where Spektr (Spectrum) was a name for the whole series of space observatories, while UF stood for the Russian "Ultra-Fioletovy" -- ultraviolet. According to the original plan, Spektr-UF would be an almost six-ton spacecraft carried into a high elliptical Earth orbit by the Proton rocket in 1997. This time, Russian astrophysicists hoped to lead a truly international effort with the data from the spacecraft widely shared among the world's scientific community.

Scientific capabilities of the Spektr-UF spacecraft were promised to be unmatched by any other instrument at the time. (452) Even though it would be physically smaller than its main predecessor -- the Hubble Space Telescope, HST, Spektr-UF's telescope would be an order of magnitude more sensitive than the UV instrument on the Hubble. Hubble's official successor -- James Webb Space Telescope, funded by NASA and ESA and scheduled to fly around the same timeframe as Spektr-UF in the second half of 2010s, was designed to conduct observations in the infra-red range of spectrum, leaving ultraviolet light "beyond its view." With its ultraviolet vision, the Spektr-UF promised to benefit two crucial fields in astrophysics: the formation of stars and planetary systems and the cosmological and chemical evolution of the interstellar and intergalactic medium. (609)

The spacecraft would carry a Russian-built T-170M telescope with a mirror diameter of 1.7 meters. (T-170M is a smaller, lighter version of its predecessor -- T-170 -- which never had a chance to fly in the wake of the post-Soviet economic turmoil.) Light captured by the instrument will be directed into three spectrometers sensitive to wavelengths from 102 to 310 nanometers. They were designed to register radiation from cosmic plasma with temperatures of several ten thousands Kelvin and atomic transition lines of all important atoms and molecules like H2, CO, OH and others. This capability would allow an international team of scientists to study formation of galaxies and analyze the atmospheres of exoplanets (planets outside our solar system) and protoplanetary discs.

In the first two years of its mission, Spektr-UF will spend 40 percent of its observation time for the so-called "base program" compiled by the project's main scientific committee. A half of available observation time will be split between astronomers from countries-members of the Spektr-UF project, proportional to their nations' investments. Finally, remaining 10 percent would be dedicated to the "open" program to fulfill "outstanding" proposals selected by the scientific committee among requests by non-participating parties.

As of 2011, Spanish, German and Ukrainian scientists were expected to participate in the mission. The flight control and science data receiving facilities for the project were to be deployed in Russia and Spain. Between 2007 and 2011, Kazakh and Russian space officials discussed a possible ground station in Kazakhstan for receiving and processing data from Spektr-UF, as Kazakh contribution into the project. (605)


Like most post-Soviet space projects, Spektr-UF went through several painful incarnations and delays caused by funding problems and changing priorities within the Russian space program. For almost two decades, Spektr-UF was standing in line to the launch pad behind the Spektr-RG X-ray observatory and the Spektr-R radio-telescope. The stalled scientific program of Spektr-UF ended up in the lap of a small and underfunded team led by Boris Shustov at the Institute of Astronomy, INASAN, in Moscow. Around 2003, NPO Lavochkin had to dramatically scale down Spektr-UF and re-design it around its standard Navigator service module, so the whole spacecraft could fit into a smaller, cheaper rocket than Proton.

In 2004, when discernable Russian funding for the project started flowing, one source promised the launch of Spektr-UF as early as 2008 into an orbit around Lagrange L2 point, some 1.5 million kilometers behind the Earth along the line extending from the Sun. At that location, the spacecraft would avoid constant passes through the shadow of the home planet and thus keep ultra-delicate optics free of severe temperature swings. This orbit would also enable the so-called spectroscopic monitoring which is in high demand by the astronomical community and difficult to carry out with the Hubble Space Telescope due to its low Earth orbit. (609) As a drawback, deploying the spacecraft in L2 point would require more than one ground station to control the mission, which would inevitably lead to a higher cost of the whole project. (611) As a result by 2006, Spektr-UF was promised to lift off in late 2011 on the Zenit-3M/Fregat-SB rocket into a geosynchronous circular orbit with an altitude of 35,786 kilometers and an inclination of 51.6 degrees toward the Equator for a decade-long mission. A cheaper Chinese LM-3B rocket was also under consideration. (608)

In 2009, the mission slipped to 2013 at the earliest, while none of the critical hardware for the project was ready and neither was ground infrastructure required to test those systems. In addition, Germany was not able to fund a pair of UV-spectrographs, leaving the project without critical instruments. At the time, the assembly of the Navigator service module for the observatory was not expected to start until 2010.

In 2010, the project was delayed again to 2014, and even that date was according to most optimistic scenarios. In May 2011, the launch was expected no earlier than by the end of 2014. By July 2011, a newly appointed head of the Russian space agency, Vladimir Popovkin, was quoted as promising the mission in 2015.

In the meantime, according to sources in Germany, cost overruns in the preceding Spektr-RG project consumed funding reserved for the German participation in the Spektr-UF mission. Germany was expected to supply a spectrography package for the project, however following the nation's withdrawal, Russian VNIIEF institute took over this responsibility beginning in 2011.

In May 2012, a publication of the Moscow Physical and Technical Institute, MIFTI, quoted Deputy Director of the Astronomy Institute, INASAN, Dmitry Bisikalo as saying that Spektr-UF was scheduled for launch in 2016. (571)

In 2012, Roskosmos ordered the manufacturing of the Proton-M/Briz-M rocket for the mission with a completion date in November 2014, thus switching the launch from Zenit. In the same year, NPO Lavochkin issued its first press-release dedicated to the Spektr-UF mission. On October 17, the company announced that it had completed tests of the antenna system on a dedicated antenna prototype of the Spektr-UF spacecraft. The company had also built a prototype of the observatory intended for structural tests and tested it for expected static, vibration and transportation loads. Lavochkin was also completing the construction of prototypes intended to test the thermal control system.

After years of delays, the flight version of the T-170M telescope was also being manufactured. In parallel, the Institute of Astronomy, INASAN, was working on technical prototypes of Russian science spectrograph and associated avionics which were scheduled for delivery to Lavochkin in 2013, the company said.

2014-2015: The Ukrainian crisis threatens to derail the Spektr-UF project

In 2014, the Spektr-UF project suddenly faced new hurdles in the wake of the Russian conflict with Ukraine. First off all, the Ukrainian contribution into the project was derailed, even though scientists on both sides would prefer to continue the cooperation.

Even more significantly, the Western sanctions affected the import of critical components for the observatory. The main spectrometer on Spektr-UF was to be equipped with state-of-the-art detectors of ultraviolet light. Due to lack of such technology in Russia, developers planned to purchase necessary hardware from the UK-based company e2v, which in turn, relied on US components. In May 2014, the leading scientist in the project Boris Shustov told the Argumenty i Facty weekly that slightly more than a month earlier the British side had informed him that the US had discontinued the supply of their components under the sanctions regime. "At this moment we have to resolve this problem," Shustov said.

According to some rumors, Roskosmos officials were deciding whether to continue the Spektr-UF project at all, even though the official video from NPO Lavochkin showed the work on the Spektr-UF's hardware at the beginning of 2014. By the middle of the year, the head of NPO Lavochkin said that Spektr-UF had had an uncertain launch date. At the time, sources at the company indicated that the launch of Spektr-UF would have to be pushed back from 2018 to as far as 2024. During the 40th assembly of the Committee on Space Research, COSPAR, in August 2014, Lev Zeleny, the director of the Space Research Institute, IKI, which took over responsibility for scientific instruments of Spektr-UF, promised the launch in 2020.

In the wake of significant budget cuts in the Russian space program in April 2015, the project was pushed back by a year from the first half of 2020 to the first half of 2021. It was now expected to be launched on a Proton-M/Block-DM rocket instead of a Ukrainian-built Zenit.

The revised version of the Federal Space Program covering the period from 2016 to 2025, which was approved at the end of 2015, allocated a total of 10.11 billion rubles for the project (approximately $127 million as of 2016) with a projected launch in 2021:

The approved budget for the Spektr-UF project, (as of Dec. 23, 2015):

Annual budget
In millions of rubles

Developments in 2016

In August 2016, the Rossiya TV channel released footage of hardware for the Sepktr-UF observatory undergoing processing at NPO Lavochkin, including the focal structure of the T-170M telescope.


A focal structure of the Spektr-UF observatory during processing at NPO Lavochkin circa 2016.

According to industry sources, NPO Lavochkin made good progress customizing the Navigator service module for Spektr-UF and developing the T-170M telescope structure. However many problems still remained in the development of scientific instruments for Spektr-UF, causing some concerns even about a relatively remote launch date for the mission in 2021. As of the end of 2016, the final electrical tests of the spacecraft, which would require the availability of all its scientific payloads, were set for the end of 2019.

As of April 2015, the launch was still promised in 2021, but by May 2017, the mission was postponed until 2024. By 2019, the mission slipped to an uncertain period sometimes after 2025. By 2021, it was confirmed that the launch of Spektr-UF would have to be postponed until to 2027 or 2028 and moved from Proton to Angara-5.

In May 2022, Deputy Director for Science at the Institute of Astronomy of the Russian Academy of Sciences, INASAN, Mikhail Sachkov announced a contract with NPO Lavochkin for the development of scientific payload for the Spektr-UF telescope, which he claimed had been scheduled for launch in 2025, likely citing long-obsolete official plans. However, at the end of 2022, Roskosmos confirmed that the mission was then expected to fly in the fourth quarter of 2028.


Evolution of the Spektr-UV project:

As of 1995 (118)
As of 2001
As of 2004
As of 2011-2012
As of 2016
Telescope (T-170) sensitivity range
102 to 310 nanometers
102 to 310 nanometers
110-310 nanometers (>100-350 nm (606))
Projected launch date
Launch vehicle
Zenit-2SB or Long March-3B
Spacecraft bus
Spacecraft mass
5,870 kilograms
2,250 kilograms
2,250 kilograms
2,840 kilograms (607)
Payload mass
2,500 kilograms
1,600 kilograms
1,600 kilograms
1,600 kilograms
12.5 meters
9.604 meters
9.604 meters
9.604 meters
Maximum span
18 meters
17.05 meters
17.05 meters
17.05 meters
Electrical power available for the payload
800 Watts
750 Watts
750 Watts
750 Watts
Science data downlink rate
2 megabytes
up to 4 megabytes
300,000 by 500 kilometers, 51.6 degrees
Geosynchronous, 51.6 degrees
Sun-Earth L2 Lagrange point
Geosynchronous, 51.6 degrees
Projected life span
10 years
7 years (607)
$400 million


Specifications of the T-170M telescope onboard Spektr-UF spacecraft:

Architecture type
Angle of view
0.5 degrees (30 angular minutes)
Focal length
17 meters


Spektr-UF development team:

NPO Lavochkin
Prime developer
Academy of Sciences Astronomy Institute
Main science program developer and user
Lytkarin Plant of Optical Glass, LZOS
Optical systems of the T-170 telescope
Spectrograph package
NPO Luch
Optical sensor/mirror coating
Onboard science program, control system, navigation trackers
ISS Reshetnev
Driving mechanism for antennas and solar panels (613)
Tomsk State University
Meteoroid shielding


Foreign participation in the Spektr-UF project (planned and under consideration during the development of the project) (610):

Prime developer
In development
Ground facility
In development
Possible ground station
South Africa
Possible ground station
Coating of the optical elements; contractor on the Zenit launch vehicle; (possible ground station (?)
The Russian-Ukrainian conflict likely derailed the cooperation in 2014
High-resolution spectrograph
Withdrawn due to lack of funds
Long-slit spectrograph, LSs, ground station, an alternative launch vehicle
United Kingdom
Contribution to a long-slit spectrograph, LSS
Three-channel field imaging camera, ground station in Kenya
Possible cooperation
Possible cooperation
UV cameras
Possible cooperation


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This page is maintained by Anatoly Zak

Last update: December 30, 2022

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insider content


A decorative model of the Astron satellite. Copyright © 2011 Anatoly Zak



A full-scale prototype of the European TD-1A satellite, which registered ultraviolet radiation from 60,000 starts from March 1972 to May 1974. Copyright © 2009 Anatoly Zak


A German-built CRISTA-SPAS platform carrying a cluster of ultraviolet telescopes was deployed and retrieved by the Space Shuttle in 1993 and 1996. Copyright © 2010 Anatoly Zak


A body of a 0.8-meter Spika UV-telescope for the Astron orbital observatory built by NPO Lavochkin. Copyright © 2000 Anatoly Zak


Spektr UF

Evolution of the Spektr UF (UFT) spacecraft during the 1990s, when it was based on the AM module. Credit: NPO Lavochkin


Development of the telescope for the Spektr-UF project circa 1995. Credit: NPO Lavochkin

Spektr UV

A scale model of the Spektr UF telescope in its circa 2000 configuration. Click to enlarge. Copyright © 2008 Anatoly Zak


Around 2004, a Chinese LM-3B rocket was considered as a launcher for Spektr-UF. Copyright © 2005 Anatoly Zak


If launched around 2016, Spektr-UF could become the main tool of ultraviolet astronomy after the retirement of Hubble Space Telescope, HST. Copyright © 2011 Anatoly Zak


The main mirror of the Spektr-UF's telescope during processing circa 2012.



Assembly of the Spektr-UF prototype circa 2012. Credit: NPO Lavochkin



Views of the Spektr-UF telescope released in 2016. Credit: NPO Lavochkin

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