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Above: A general design of the Spektr-R spacecraft.

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Previous chapter: Development of the Spektr-R observatory

Russian space science to be reborn

Triumphing over three decades of historic cataclysms, economic problems and social cynicism, Russian astrophysical science re-invaded the outer space with its first 21st-century orbital observatory. The historic importance of the Spektr-R mission, which successfully reached orbit Monday morning, is difficult to overestimate. It is enough to say that the last time Russian astrophysicists had a dedicated spacecraft of comparable significance working in space, the USSR was still in existence and today's young adults had not been born yet. Since then, the Russian space science was largely written off by wider public, as the nation's scientific spacecraft inherited from USSR had remained grounded by economic foes, social neglect and mismanagement resulting in the virtual decimation of the country's scientific potential.

Only with a gradual improvement in funding in mid-2000s, Moscow-based NPO Lavochkin and its partners managed to jump-start most crucial scientific projects with the Spektr-R radio-telescope at the top of the priority list.

A Zenit rocket carrying the Spektr-R satellite lifted off into cloudless sky as scheduled on July 18, 2011, at 06:31:14.358 Moscow Summer Time (10:31 p.m. EST Sunday) from Site 45 in Baikonur Cosmodrome, Kazakhstan. The shutdown of Zenit's second stage main engine was confirmed 430 seconds after the liftoff, followed by the normal burn and a shutdown of the steering engines of the stage until a 520th second in flight. The Fregat upper stage and the Spektr-R stack then separated in its initial parking orbit. Following further maneuvers, Fregat released Spektr-R in a seemingly correct orbit, ushering a new era in the Russian space science. According to NPO Lavochkin, a prime-developer of the Spektr-R observatory, the first communication session with the spacecraft was successful. In the meantime, Russia's official RIA Novosti news agency quoted the head of NPO Lavochkin, Viktor Khartov, as confirming the opening of the observatory's solar panels, the establishment of the correct attitude control relative to the Sun and reliable contacts with ground stations in Medvezhi Ozera and Ussuriisk. Khartov promised a switch to a three-axis attitude control three days in the mission and the opening of the main telescope antenna two days later.

Bulky antenna

Around noon Moscow Time, on July 22, 2011, a poster on the online forum of the Novosti Kosmonavtiki magazine reported that the crucial operation of the opening of the giant flower-like antenna onboard Spektr-R/Radioastron had began. The slow-motion process was expected to take hours, however around an hour and half later, the official Russian media hurried with reports that the opening had been completed. The official RIA Novosti news agency then quoted the chief designer of the Radioastron project, Vladimir Babyshkin, as saying that the ground control had received the first telemetry confirming that the opening of antenna petals had been underway. Unofficial reports said that the opening had been almost completed, however latches of petals, which would hold the dish in open position, had failed to close requiring to repeat the process. Several following attempts to lock the antenna apparently also failed, unofficial sources said. Flight controllers several times commanded the petals to move slightly toward folding position and then move back into the open position, however a required signal for closing of latches at the tips of petals still did not come. The antenna was finally left in an open but unlatched position.

A special meeting at NPO Lavochkin was scheduled for the next morning, around 09:00 Moscow Time, to evaluate the problem. According to sources at FIAN institute, which led the observatory's scientific program, the radio telescope would still be able to conduct its scientific studies despite an unlatched antenna, with some minor deterioration of data.

On the morning of July 23 (Moscow Time), a new attempt to deploy the antenna was made and, this time, it quickly resulted in a successful completion of the operation. According to postings on a web forum of the Russian astronomical community, all latches of the antenna had been fully engaged, triggering necessary confirmation signals from onboard sensors. Russia's first space observatory was open for business. According to sources involved in the project, during a break in the opening effort, the spacecraft was reoriented in space so that its main antenna was exposed to the Sun and the heating could alleviate some tension in the mechanism caused by extremely low temperatures. During the final operations, the opening mechanism was applying the maximum load of 1,200 kilograms onto the petals, instead of nominal 600 kilograms. However, in the previous attempt even that pressure reportedly failed to complete the opening.

Besides extremely low temperatures, the resistance of thermal protection layers, which might had not been adequately represented during ground tests, was considered as a potential culprit for the deployment problems. Finally, some slight errors in the mass-negating mechanism, which was designed to imitate the conditions of weightlessness on the ground, might had made it too easy for the antenna to open during pre-flight tests.

A successful opening of the main radiotelescope antenna was followed by activation of other instruments onboard the spacecraft. Space Research Institute, IKI, reported that the activation of the Plasma-F experiment started on July 25, 2011, with powering up the SSNI-2 unit for gathering, storage and processing of scientific information. Other components of the complex were to be turned on in the next week or two, IKI said. The magnitometer MMFF and the MEP particle detector were activated on July 30.

Freezing temperatures hamper testing

On July 25, the guidance mechanism of the high-gain antenna onboard Spektr-R was disconnected from its launch stowage position and the device could now move freely to track ground stations. A day later, RIA Novosti news agency quoted the head of Radioastron project, Nikolai Kardashev, promising the opening of a specialized channel for the transmission of science data from Spektr-R spacecraft by August 4.

Following the calibration of the space-based radio telescope, the regular scientific data from the observatory could start coming at the end of September - beginning of October 2011, Kardashev said. (497)

The first attempt to establish a communication channel for downlinking scientific data from Spektr-R to the ground station in Pushino took place on Aug. 4, 2011. However even though the 22-meter radiotelescope in Pushino was powered up, the attempt had to be postponed. Ground controllers found temperature onboard the telescope around -15 degrees C - considerably lower than nominal 0 - 20 degrees C required for normal operations. Mission controllers took actions to warm up the spacecraft, however the progress was too slow, requiring to postpone the delivery of science data until the next available window on August 13. Still, mission officials said that the spacecraft can operate within a range of temperatures from -25 to +70 degrees C.

According to unofficial reports, a critical hydrogen frequency standard onboard Spektr-R was also activated with a delay due to lower than expected temperatures.

Initial communications tests were limited to communications at 8.4 Gigahertz dedicated to the transmission of technical data only. The transmission of actual science data at a frequency of 15 Gigahertz was scheduled to take place for the first time on August 18. (504) On that day, NPO Lavochkin did announce that attitude control flywheels onboard Spektr-R had been tested and that ground controllers had been monitoring temperature onboard the spacecraft under conditions of constantly changing orientation relative to the Sun. There were also efforts to establish more precisely the satellite's orbital parameters on the basis of ground tracking information and checks of high-volume radio channel of the radiotelescope. The company's press-release promised testing of science data transmission to begin in September. In the meantime, according to the project's sources, during the night from August 21 to August 22, a transmitter onboard Spektr-R was used successfully for the first time to downlink data to a receiving station in Pushino.

Scientific observations begin

On September 27, 2011, the Spektr-R telescope started scientific observations capturing its "first light" from the brightest natural radio source in the sky known as Cassiopeia A, an ancient exploded star. The telescope scanned across the supernova remnant in two perpendicular directions. Signal in two bands of 92 and 18 cm (two circular polarization per band) was successfully detected in the total power mode. Enjoy the first light picture attached.

As part of its early science program, RadioAstron joined the Green Bank Telescope in the US; Very Large Array, VLA; the Atacama Large Millimeter/submillimeter Array, ALMA, and the Very Long Baseline Array, VLBA, telescopes to achieve a resolution better than one ten-thousandth of an arcsecond, which is several hundred times better than the Hubble Space Telescope and the highest resolution ever achieved in astronomy.

"The RadioAstron early science program, which has just finished (in mid-2013), has already brought many surprises to scientists studying quasars, pulsars, and interstellar medium," said Yuri Kovalev, the Spektr-R project scientist from the Lebedev Physical Institute of the Russian Academy of Sciences, was quoted as saying in August 2013.

A US-based telescope joins Spektr-R project

From late July through early August of 2013, thanks to funding from Roskosmos, engineers and astronomers from the United States and Russia successfully installed sophisticated receiving and signal processing instruments on the 43-meter radio telescope from the Green Bank Radio Observatory, NRAO, in the US state of Virginia, which was completed in 1965 and retired from routine astronomical observations in 2001, NRAO announced on Aug. 15, 2013.

On Aug. 1, 2013, Green Bank telescope successfully established its first contact with Spektr-R, becoming only the second location worldwide capable of "listening" to the Russian space observatory. The introduction of the ground station in the Western hemisphere would double the time available for observations with Spektr-R.

"By combining (Spektr-R's) data with leading ground-based telescopes, we will have an incredibly powerful research tool, which will provide extraordinary angular resolution enabling the study of quasars, cosmic masers, and the interstellar medium in unprecedented detail," Ken Kellermann, a scientist at the NRAO in Charlottesville, Va., was quoted as saying in the NRAO's official press-release.


 

APPENDIX

Spektr-R Radioastron planned launch sequence

The Spektr-R spacecraft was expected to climb into orbit on July 18, 2011, according to a following flight profile (Moscow Summer Time):

Event
Time
Perigee, km
Apogee, km
Inclination
Period, min
Liftoff
06:31:18
0
0
-
-
Separation of Stage II of Zenit rocket
06:39:56
177.0
447.0
51.4
-
First Fregat SB burn (488 seconds)
07:29:48
445.7
3,708.6
51.47
128.8
Fregat SB external tank separation
07:38:33
-
-
-
-
Second Fregat SB burn (894 seconds)
09:35:17
2,935.9
335,094.0
51.6
11,529.6
Spektr-R separation from Fregat SB
10:06:59
1,045.3
332,728.0
51.6
11,527.2

 

Next chapter: Spektr-RG

 

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Page author: Anatoly Zak; Last update: August 16, 2013

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IMAGE ARCHIVE

Zenit

A Zenit rocket with the Spektr-R spacecraft rolls out to the launch pad on July 16, 2011. Credit: Roskosmos


Launch

Launch

A Zenit rocket with the Spektr-R spacecraft blasts off on July 18, 2011. Credit: Vesti 24


Below: A sequence of renderings illustrating a ride to orbit and deployment of the Radioastron observatory. Credit: NPO Lavochkin

Separation

An external tank separates from the Fregat upper stage.


Fregat

The Fregat upper stage separates from Spektr-R, after delivering the observatory into its operational orbit.


Solar panels

Spektr-R deploys its solar panels.


Antenna

Spektr-R prior to the antenna deployment.


deploy

An initial stage of the antenna deployment.


 

 

 

 

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