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How Spektr-RG was built (2009 - 2014)

Improved funding of the Russian space program after 2005 finally gave some confidence to developers that Spektr-RG would eventually fly. Still, the overall poor state of the Russian space science program, particularly problems in the construction of hardware, kept pushing the launch date for the "reborn" Spektr-RG years behind schedule. Some "unfeasible ideas" in the configuration of the spacecraft were also cited by project sources as reasons for delays.

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Navigator design

Spektr-RG as of 2011.



Launch delays

When the first plans to revive the defunct Spektr-RG project were made around 2004, the launch of the observatory was publicly promised in 2006, probably based on the final schedule of the original spacecraft. However, soon thereafter, official sources began citing the end of 2007 and 2008 as the launch dates for the revived satellite. In 2008, the official launch date was set as November 20, 2011.

By August 2009, when the final agreement on Spektr-RG was struck between Roskosmos and DLR, the end of 2012 was considered the earliest possible launch date for Spektr-RG, or just three years later. However, by December 2010, the launch date was already expected to drift to the first quarter of 2013. (441)

In his 2013 interview, Mikhail Pavlinsky, Deputy Director for Science at Moscow-based Space Research Institute, IKI, and the head of high-energy astrophysics department, said that the switch of the mission from the Earth's orbit to the L2 Lagrange point in the Earth-Sun system required replacing all the electronic components aboard the spacecraft and its instruments because they would no longer be protected by the planet's magnetic field from harsh space radiation. According to Pavlinsky's interpretation, the transfer from Earth's orbit to Lagrange was prompted by the requirements from an X-ray calorimeter proposed for installation aboard Spektr-RG, which featured a power-hungry cooling system and thus could not function for long periods in the Earth's shadow. Although, the instrument was ultimately dropped from the payload list, the Spektr-RG remained bound to the Lagrange point, Pavlinsky said. (871)

Developments in 2011

In 2011, the manufacturing of both telescopes for the Spektr-RG mission was finally under way in Russia and Germany and delivery of the instruments to integration in Russia was promised at the time as early as 2012.

At the beginning of March 2011, the mission was promised to lift off in September 2013. Speaking at the Duma (parliament) in the Fall of 2011, Head of Roskosmos Vladimir Popovkin still promised the launch of Spektr-RG in 2013.

According to the official schedule remaining in force as late as December 2011, the launch of Spektr-RG was set for November 13, 2013. (According to NPO Lavochkin, a three-day launch window would be available every three days.)

However, during an astrophysics conference at the Space Research Institute, IKI, in Moscow, on Dec. 13-16, 2011, the organization's officials discussed ballistics of the Spektr-RG launch on March 22, June 22 and Sept. 22, 2014.

Of course, even the most pessimistic pronouncements at the time turned out to be off by half a decade.

Communications challenges

Following the Phobos-Grunt launch fiasco at the end of 2011, all planetary exploration and science projects in Russia faced an uncertain future. In particular, the mission to Phobos was expected to test an X-band deep-space communications system, which was needed for Spektr-RG. Following the loss of the spacecraft, NPO Lavochkin considered trials of the X-band package on a small-size MKA-FKI satellite (the second or third satellite in the MKA series).

In November 2012, a representative of IKI's high-energy astrophysics department Mikhail Pavlinsky told RIA Novosti that the radio-systems onboard Spektr-RG would be re-worked to make them compatible with Western ground stations, which could back up the Russian ground control.

Ilya Lomakin, a leading engineer at NPO Lavochkin, was also quoted as saying that the developers had considered replacing the original radio system on Spektr-RG with the hardware inherited from the European Planck observatory and from the Russian Spektr-R spacecraft, however the idea had been dropped because it would reduce the reliability of the system.

In the wake of the Phobos-Grunt failure, NPO Lavochkin also requested the replacement of many avionics components aboard Spektr-RG with hardened versions graded "military" and "space." The flight control system also had to be upgraded with a special timer designed to re-boot the computers and implement a number of other measures to improve reliability, Lomakin told RIA Novosti.

To reduce the risks associated with the radio system, NPO Lavochkin also formed a joint Russian-German expert group, which was assigned to supervise, audit and perform quality control during the development of the radio system at RKS Corporation, according to Interfax, quoting NPO Lavochkin.

In the meantime, separate delays with the delivery of Spektr-RG's scientific instruments required publicly pushing back the launch date for the observatory to 2014.

Around the same time, ISS Reshetnev in Zheleznogorsk, a leading Russian satellite developer, revealed its work on the contract with NPO Lavochkin on the development of a guiding mechanism for the high-gain antenna on Spektr-RG and Luna-Glob missions. The flight version of the guiding mechanism for the antenna on Spektr-RG was scheduled for delivery to Lavochkin in 2013, ISS Reshetnev said. The same company was also building solar panels for the spacecraft.

Developments in 2012

By Spring 2012, the VNIIEF nuclear center, in the town of Sarov, manufactured and tested a full-scale mass and thermal prototype of the main telescope and was working on the second (engineering) prototype of the device. A representative of the center, Dmitry Litvin promised to start the construction of a fully functional ground equivalent as well as the flight version of the instrument before the end of the year. (568)

At the end of May 2012, the schedule called for the vibration tests of the Spektr-RG engineering model equipped with development mockups of the main instruments to start in June or July, but in reality, these tests apparently started only in September and lasted until the end of 2012. At the same time, development versions of the Russian and German telescopes for Spektr-RG were scheduled for delivery in June and September respectively to pave the way for integrated tests. Vibration trials were to be followed by electrical tests also before the end of 2012. In the meantime, the shipment of the flight version of the German-built eROSITA telescope to Russia was planned for June 2013, followed by the delivery of Russian-built ART-XC in October of the same year. This timeline would enable the launch of the mission in the Fall 2014.

In September 2012, NPO Lavochkin finally published its first press-release on the status of the Spektr-RG project, announcing that it had been conducting the testing of the antenna system on the prototype of the spacecraft. According to the company, a prototype of the spacecraft for testing of its structural strength and design had been manufactured. Static and transportation tests had been completed and vibration tests had been underway, Lavochkin said. In parallel, testing of the thermal-control system had been completed on the flight prototype of the spacecraft, while the assembly of another "prototype for flight testing" were underway, Lavochkin said. The company also announced that the Space Research Institute, IKI, in Moscow had manufactured the technical version of the ART-XC telescope for the spacecraft and was preparing to ship it to NPO Lavochkin. The press-release was accompanied by an undated and uncaptioned photo apparently showing one of the prototypes of the Spektr-RG observatory.

Mechanical tests of the observatory were conducted from September to December 2012. Final tests of the spacecraft were scheduled for April 2014, upon the delivery of the long-delayed radio system.

Speaking at a conference on astrophysics in December 2012, Mikhail Pavlinsky said that the project had been moving forward quite slowly and the launch date for the mission had moved to the third quarter of 2014. At the same conference, a leading engineer at NPO Lavochkin Ilya Lomakin promised the delivery of the spacecraft to the launch site in the third quarter of 2014 and the launch in the fourth quarter of the same year.

Developments in 2013

In March 2013, NPO Lavochkin said that prototypes of the Spektr-RG for design verification, vibration and antenna testing had all gone through their respective tests at the company's facilities. Lavochkin also completed the so-called proto-flight model of the spacecraft (which eventually would be assembled into the flight-worthy spacecraft) and was preparing it for transfer to the Checkout and Test facility, where it would undergo electric and radio tests. The spacecraft was fully outfitted, except for a radio system. The company also had a technical prototype of ART-XC telescope and an electric simulator of eROSITA. At the time, the Space Research Institute, IKI, was still building the test prototype and the flight version of the ART-XC. In the meantime, in Germany, specialists were assembling the flight version of the eROSITA telescope, but its structural, thermal and vacuum tests had been successfully completed, confirming the sound design of the instrument, NPO Lavochkin said.

The manufacturing of the launch hardware, such as the payload fairing for the rocket, the transfer section and adapters for connecting the spacecraft to the upper stage, as well as the separation system, had all been manufactured, according to NPO Lavochkin.

At the time, the meeting of the Chief Designer Council overseeing the Spektr-RG project was scheduled for April and the launch of the mission was still promised in 2014.

However, by the end of May 2013, new problems required the postponement of the launch of Spektr-RG from the end of 2014 to 2015. On the Russian side, the biggest obstacle continued to be the X-band radio communications system for the spacecraft. According to project sources, NPO Lavochkin was then considering a switch from a movable High-Gain Antenna on the spacecraft to a less-capable Medium-Gain Antenna. (A horn-like fixed antenna was eventually chosen for the spacecraft, even though the large antenna dish continued to be present on most depictions of the spacecraft all the way until its launch in 2019.)

On July 16, 2013, NPO Lavochkin announced that the systems of the Spektr-RG's service module had gone through radio and electric tests at the company's test and checkout station, KIS, with the exception of the radio complex, which was represented by a prototype.

A test version of the Russian ART-XC telescope and the electric simulator of the eROSITA telescope were going through initial acceptance tests, the company said. NPO Lavochkin was also completing a clean room facility to handle the flight version of scientific payloads for Spektr-RG.

In the meantime, in Germany, developers hit a major problem during the integration of around 60 circuit boards with up to 30,000 individual components on the eROSITA telescope. The latest tests reportedly uncovered previously unknown incompatibility between programmable radiation-resistant electronics and regular circuit boards, requiring a major redesign of onboard electronics, which would take at least a year and a half. As a result, by July 2013, the German team had to postpone the delivery of the flight-worthy eROSITA to NPO Lavochkin from December 2013 until June 2015. The head of NPO Lavochkin Viktor Khartov publicly confirmed the delay at the end of August 2013.

As of October 2013, electrical interface tests on eROSITA were yet to be performed. Nevertheless by November 11, the German team integrated the last of 432 mirror shells into the telescope, finally completing the assembly of all seven flight mirror modules for eROSITA and one spare module.

Developments in 2014

In 2014, the Applied Mathematics Institute, IPM, of the Russian Academy of Sciences, which is traditionally tasked with calculating trajectories of the Russian space missions, published eight possible launch dates for the Spektr-RG from March 15, 2016, until June 30, 2016. Within this launch window, the spacecraft could be launched on the 15th and the 30th of each month, according to IMP. As of June 2014, the launch of Spektr-RG was officially promised on March 26, 2016.

However on April 9, the Council of Chief Designers, which oversaw the Spektr-RG project, reviewed the latest status of the observatory's development. At the time, the delivery of flight versions of German eROSITA telescope and the Russian ART-XC telescope was planned between July and October 2015, making it possible to launch the observatory no earlier than the first quarter of 2017, if no other major problems interfered with the schedule.

Evolution of the Spektr-RG mission:

as of 2009
as of 2012
as of 2014
as of 2015
Planned launch date
2012 (The 2013 was considered as more realistic)
2016 March 26
2017 Sept. 25
2018 September - 2019 June
Spacecraft mass
2,400 kilograms
2,385 kilograms (dry mass: 2,115 kg)
2,712.5 kilograms*
Payload mass
1,100 kilograms
1,100 kilograms
1,200 kilograms
Projected mission lifetime
3-7 years
7.5 years
7.5 years
No less than 7 years
6.5 years
Electrical power available for the payload
680 Watts
nearly 700 Watts
Onboard propellant mass
360 kilograms
Launch vehicle
Operational orbit
L2 Libration point in the Sun-Earth system
L2 Libration point in the Sun-Earth system
L2 Libration point in the Sun-Earth system
L2 Libration point in the Sun-Earth system
L2 Libration point in the Sun-Earth system

*To be clarified at launch site


Specifications of science instruments onboard Spektr-RG (589):

Sensitivity range
0.3 - 10 keVolts
(5) 6 - 30 keVolts
View angle
1 degree
30 minutes
Angular resolution
15 seconds
45 seconds
Sensor area (grasp)
2,400 square centimeters per 1 keVolts
450 square centimeters per 8 keVolts
810 kilograms
350 kilograms


Spektr-RG development team:

Role in the project
NPO Lavochkin
Prime contractor
VNIIEF nuclear research center
ART-XC telescope
Max Planck Institute
eROSITA telescope
ISS Reshetnev
A guiding mechanism of the high-gain antenna, solar panels


Next chapter: Spektr-RG project in 2015


Article by Anatoly Zak unless credited otherwise; Last update: June 20, 2019

Page editor: Alain Chabot; Last edit: June 19, 2019

All rights reserved

insider content



Side view of Spektr-RG circa 2011. Credit: NPO Lavochkin


A prototype of the Spektr-RG satellite under assembly circa 2009. Credit: NPO Lavochkin


A photo released on Sept. 18, 2012, apparently showed one of the full-scale prototypes of the Spektr-RG observatory. Credit: NPO Lavochkin


A scale model of the eROSITA telescope unveiled around 2009. Click to enlarge. Copyright © 2009 Anatoly Zak


Testing of the eROSITA telescope circa 2011. Click to enlarge.


The assembly of eROSITA telescope circa 2012. Credit: Max Planck Institute


Production of mirrors for the ART-XC telescope circa 2011.


The ART-XC telescope during testing sometimes before 2011.


A Russian satellite developer ISS Reshetnev released this photo in 2013 showing the work on the guiding mechanism of the high-gain antenna for Spektr-RG. However, the device apparently never made to the actual spacecraft. Credit: ISS Reshetnev


A footage released at the beginning of 2016, but might be dating back as far as 2014, shows what appears to be a test prototype of the Russian-built ART-XC telescope electrically connected to the Navigator service module (right). Click to enlarge. Credit: Roskosmos





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