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Koronas is the Russian abbreviation of "complex orbital near-Earth observations of solar activity." The spacecraft was designed to conduct an uninterrupted monitoring and analysis of the solar activity, crucial for uncovering long-time mysteries of the Sun, such as heating of its corona, mechanics of solar bursts and the nature of Sun cycles. According to officials involved in the project, the satellite would help to plan manned space missions, including future expeditions to Mars, by providing accurate and up-to-date forecasts of solar activity. The Sun’s influence on weather and climate on Earth would also be investigated.

Systems of Koronas-Foton spacecraft and its developers:

General description

During its projected three-year lifespan, the spacecraft could snap as many as a million of new images of the Sun. Around 200 hours of video were also expected. The satellite was intended for a 500-kilometer circular orbit with the inclination 85 degrees toward the Equator, which would enable it to monitor the Sun for as long as 25 days without any eclipse by the Earth shadow.

The satellite’s scientific payload includes an array of 12 instruments, some of which are unique in their capabilities and scientific potential. Eight instruments were designed for registering electromagnetic radiation from the Sun in a wide range of spectrum from near electromagnetic waves to gamma-radiation, as well as solar neutrons. Two instruments were designed to detect charged particles such as protons and electrons.

The Koronas-Foton project was led by a Moscow-based astrophysics center at Engineering and Physical Institute, MIFI, with the participation of prominent scientific organizations in Russia, India, Poland and Ukraine.

Project history

Original plans made around 1992 called for the launch of three Russian solar telescopes: Koronas-I in 1993, Koronas-F in 1994 and Koronas-Foton in 1995. The constellation would enable a constant monitoring of the Earth's closest star during its 11-year activity cycle. However, economic problems in Russia pushed these plans a decade behind schedule. By the turn of the 21st century, the 2001 Koronas F mission would be followed in 2004 by the launch of the AUOS-SM-F (Koronas-Foton) spacecraft. As two previous satellites in the series, it would be based on the AUOS-SM satellite platform developed at KB Yuzhnoe based in Dnepropetrovsk in the former Soviet republic of Ukraine. However to avoid dependency on a newly independent state, Russian space agency decided to find a prime developer inside Russia. Initially, NII Elektromekhaniki, also known as NIIEM and based in the town of Istra near Moscow was chosen as a prime developer. However later, NIIEM's former parent company -- Iosifiyan All-Russian Institute of Electrical Mechanics, VNIIEM -- wrestled away the control over the project. Both Russian companies relied on a tried and tested Meteor-3 remote-sensing satellite as a platform for the new Koronas-Foton architecture.

Shift of a prime contractor inside Russia ended dependency on Ukraine, however the same move "locked" the project into an obsolete satellite bus, which could provide only limited attitude control and stabilization capabilities for the cutting-edge astrophysics research. Koronas-Foton's Precision Sun Sensor, TDS, could provide the stabilization accuracy of only 5 angular seconds per second, in comparison to 0.4 angular seconds provided by the Koronas-F's attitude control system and 0.1-0.5 angular seconds achievable on Western's SOHO and STEREO satellites.

However Koronas-Foton's mission planners tried to compensate for this deficiency by adding an unprecedented array of instruments, covering widest possible range of spectrum in a single satellite.

Preparing the mission

Originally the launch of the Koronas-Foton was scheduled as early as 2004. (324) The mission was eventually pushed to the fourth quarter of 2007. As of March 2008, the launch of the Koronas-Foton was expected on June 1, 2008 and then slipped to September 2008. However, a critical meeting of chief designers reviewing the overall status of project took place at VNIIEM only on Oct. 9, 2008. At the time, the launch was expected in the fourth quarter of 2008. By November 2008, the launch date slipped to Dec. 15, 2008.

The spacecraft was delivered to Plesetsk during the night from 14th to 15th of December 2008.

The launch window was designed to insert the spacecraft into the sun-synchronous orbit, where it would be in constant daylight for as long as three weeks beginning in April 2009.

The first launch attempt

On January 29, 2009, at 15:00 Moscow Time, the Tsyklon-3 launch vehicle with the Koronas-Foton satellite was rolled out to the launch pad. At 16:15, the mission was announced to be within 15-minute readiness for launch. However shortly before a scheduled liftoff at 16:30 Moscow Decree Time (8:30 a.m. EST), the launch had to be delayed for at least 24 hours.

The Russian military, which operates the launch site, announced only that technical problems forced the scrub. However a posting on the Novosti Kosmonavtiki web forum by Anton Buslov, a member of the satellite's science team, who monitored the launch from mission control, said that launch sequence was interrupted around 59 seconds before a liftoff during the separation of the ground attachment mechanism from the Tsyklon-3 launch vehicle.

Even though, the launch window had remained open until 16:45 Moscow Decree Time, a 24-hour delay was announced after some period of uncertainty. As it transpired, a drainage valve on the second stage of the rocket had been a culprit. Mission officials hoped that the problem would be isolated to a sensor error, which would only require a 24-hour delay. However in case of more serious problems, or another scrub on January 30, 2009, the rocket with the satellite would have to be removed from the launch pad and returned to the assembly building for refurbishment.

The 24-hour delay did not require compensation for the daily movement of the Earth relative to the Sun, thus leaving the scheduled launch time the same: 16:30 Moscow Time. The launch window would still last for 15 minutes.

The launch

Russia launched an unmanned satellite designed to watch capricious behavior of our closest star – the Sun. On January 30, 2009, at 16:30 Moscow Time, the Tsyklon-3 rocket lifted off from Site 32 in Russia’s northern cosmodrome in Plesetsk, carrying the 1,900-kilogram Koronas-Foton satellite. According to Russian space officials, the Koronas-Foton spacecraft separated from the third stage of the launch vehicle at 17:14 Moscow Time, as planned. The first radio-measurement of the satellite's orbit was expected at 18:02 Moscow Time.

Shortly after the launch, the FIAN institute, which manages one of major experiments onboard the Koronas-Foton, reported that the spacecraft had been within range of ground control, solar panels had deployed and normal pressure was maintained inside the pressurized compartment of the satellite. Western radar detected the satellite in the 533 by 560-kilometer orbit, with the inclination 82.485 degrees toward the Equator.

The mission

According to FIAN, the spacecraft was initially turned toward the Sun with a low-precision sensor, which has a field of view equal to a semi-sphere. The switch to the main attitude control sensor with a field of view of six degrees was expected shortly. The first scientific results from the mission were expected after February 3, 2009, following a series of tests of onboard systems. FIAN later reported that efforts to stabilize the spacecraft along the Z axis, pointing to the Sun, had been made during the first day of the mission and that the second axis was expected to be pointed into the right direction in near future. However initial activations of the science instruments would likely be postponed beyond February 3, due to additional work with the flight control system.

Unofficial reports on Novosti Kosmonavtiki web forum said that an error during pre-launch processing prevented normal activation of the flight control system onboard Koronas-Foton. Apparently, ground crew failed to install cables transmitting activation signal from the launch vehicle to the flight control computer onboard the satellite. When during the second orbit, an activation command was sent from the ground by radio, a short circuit disabled a switch in the "on" position in the backup power supply system. As a result, the flight control team scrambled to find alternative ways to activate the computer onboard the satellite.

In addition, one of the sub-sections of the attitude control system onboard the satellite had reportedly failed and one of the power supply modules had suffered a short circuit. Still official sources insisted that the mission was proceeding normally, while posts describing in-flight problems had disappeared from the Novosti Kosmonavtiki forum, as well as from FIAN's web site.

On Feb. 17, 2009, at 18:44 Moscow Time, the system for downlink and storage of science data, SSRNI, was finally activated on the command from the ground, its developer, Institute for Space Research, IKI, announced. The first downlink of science data was expected a day later, according to IKI. Science information did start flowing on Deb. 19, first at 14:00 Moscow Time from the satellite's memory and later a coded downlink.

Onboard problems

In December 2009, the official RIA Novosti news agency reported that in May 2009, one of two main instruments onboard Koronas-Foton experienced problems, but these were resolved from the ground. In the meantime, industry insiders reported on the Novosti Kosmonavtiki forum that in July 2009, the satellite started experiencing power supply problems. At the time, one of the power supply circuits went off-line following an attempt to activate one of the instruments. After that, the second and third circuits, responsible for power supply to the pressurized compartment heater and science payloads would shut down roughly once a month due to overload.

As it transpired, two onboard batteries were unable to provide enough power to the spacecraft during its flight in the shadow of the Earth, forcing a switch to a backup system, which was also underpowered. As a result, all onboard systems except for critical service hardware would be turned off. In turn, power interruptions led to the failure of one of sub-units in the flight control system and forced a switch to a second unit.

The problem escalated around December 1, 2009, when the flight control system turned off one of the batteries, after qualifying it as inoperable. The remaining battery maintained the satellite for a day before it stopped communicating with ground control. On Dec. 11, 2009, Lebedev Institute, which managed Sun observations with Koronas-Foton, reported that due to power-supply problems, scientific payloads had been turned off on December 1.

Yet again, a strategic decision to build the Koronas-Foton on the basis of the Meteor platform turned out to be at the root of the problem. Previously used exclusively for remote-sensing observations, Meteor would be pointed with its elongated cylindrical body toward the Earth's surface. As a result, onboard heaters would never be needed, since a considerable part of the satellite would be exposed to sunlight. However in the Koronas-Foton mission, the spacecraft would be pointed toward the Sun, sharply reducing an exposure of its side surfaces to the natural heating. Such flight mode required frequent use of the onboard heater, which was unexpectedly overloading the onboard power-supply system. That fact led to accusations that developers grossly miscalculated required capabilities of the battaery resources for various onboard needs, including its heaters.

Flight controllers also suspected that problems with power supply stemmed not from the battery itself but from a slowly degrading sensor, which monitors its charge and can not be controlled or bypassed from the ground. As a result, a healthy battery might end up to be disabled.

Even if ground controllers would be able to restore communications with the spacecraft, the question remained whether its scientific functionality could be restored to any meaningful extent, sources within the project said. At the same time, scientific instruments onboard Koronas-Foton were described as very energy efficient and even small amount of power would enable their operation. As of December 11, ground controllers reportedly continued efforts to revive the Koronas-Foton satellite.

On Dec. 21, 2009, ground controllers had the first post-failure window of opportunity to communicate with the spacecraft, during its flight in daylight. There was a hope that exposure to the Sun would re-charge the satellite's batteries. However, the communication attempt during the short pass of the satellite within the range of ground control failed. On Dec. 29, the head of Roskosmos, Anatoly Perminov told Russian media that Koronas-Foton had just established contact with ground control. Officials were expecting a gradual revival of the satellite during the first ten days of January 2010, as its batteries were being re-charged. However two days after Perminov's announcement, Infox.ru web site, quoting a TESIS project representative, reported that no communications between the spacecraft and ground control had taken place since the loss of contact on Dec. 11, 2009.

At the beginning of March 2010, Sergei Bogachev, a project participant at Lebedev Physics Institute, told RIA Novosti that the fate of the Koronas-Foton project would be resolved in April. During that month the satellite would be in the sunlit phase of its orbit for almost three weeks, giving a chance to the solar panels to re-charge a depleted power-supply system. In case, the spacecraft does not return to life by the end of this period, it would have to be considered a loss, Bogachev said.

Koronas-Foton replacement

At the time of a premature shutdown of the Koronas-Foton spacecraft in December 2009, the Russian space program did not have another orbital solar telescope in the pipeline. The Intergelio-Zond spacecraft, which would study solar physics after its promised launch in 2018, was officially in development and proposals for the Koronas-Stereo satellite had been rumored. Nevertheless in mid-February 2010, a poster on the Novosti Kosmonavtiki web forum said that Space Council of the Russian Academy of Sciences was considering a possibility of building a follow-on Koronos-4-Monitor satellite, with a projected launch date in 2015.

On Feb. 22, 2010, Yuri Kotov, the director of the Astrophysics Institute at the National Nuclear Research University echoed that report by saying that a replacement for Koronas-Foton was under consideration. According to Kotov, his organization worked on a proposal to develop a new-generation spacecraft with more advanced instruments than those on the failed satellite and to extend the satellite's life span to 10-11 years. The future spacecraft could also sport orbit-correction engines. Kotov's suggestion to insert the new telescope into a near-equatorial 600-kilometer orbit raised some eyebrows, as this type of spacecraft would traditionally fly in the near-polar Sun-synchronous orbit. He justified this choice by an effort to minimize the influence of radiation on the performance of scientific instruments. Kotov indicated that Moscow-based VNIIEM, which developed the failed Koronas-Foton spacecraft, would not be guaranteed a new contract, while TsSKB Progress of Samara, PO Polyot of Omsk and ISS Reshetnev of Zheleznogorsk could all bid for the primary developer role in the project. According to one posting on the Novosti Kosmonavtiki forum in March 2010, Khimki-based NPO Lavochkin invited ISS Reshetnev to form an industrial team for the development of a follow-on to Koronas-Foton. Just few weeks before, a group of veterans of ISS Reshetnev was appointed to top positions at NPO Lavochkin.

In case Russian space agency would find ways to amend its space budget with extra funding for the project starting in 2011, the new solar telescope could be ready for launch in 2014, Kotov said. A preliminary development of the spacecraft could be funded with the money originally allocated for the operation of the ill-fated Koronas-Foton. (380) However given the recent record in the development of Russian satellites, the 2014 launch date seemed highly unlikely.

By the end of March 2010, a project to replace Koronas-Foton was identified as Solaris by the Solar System division within Space Council of the Russian Academy of Sciences. The division recommended Lebedev Physics Institute, FIAN, as a main developer of the satellite's payload. The issue of the spacecraft bus remained open at the time, with NPO Lavochkin's yet-to-be-flown Navigator platform as one of the contenders. Unlike Koronas-Foton, the new telescope was expected to be narrowly specialized in solar observations and it was to be inserted into very high orbit to minimize the shadow from Earth and the influence of the planet's radiation belt. As of April 2010, the project was yet to be approved for the inclusion into the Russian space program or to receive any funding.

APPENDIX

Technical requirements for the Koronas-Foton project (as of 2001)(324):

This page is maintained by Anatoly Zak. All rights reserved. Last update:April 10, 2010

PICTURE GALLERY

An artist rendering of the Koronas-Foton satellite circa 2001. Credit: NIIEM

The Koronas-Foton satellite during the pre-launch processing in January 2009. Click to enlarge. Credit: Roskosmos

The Koronas-Foton satellite is being integrated with the Tsyklon-3 launch vehicle in Plesetsk in January 2009. Click to enlarge. Credit: Roskosmos

BELOW - First images of the Sun taken by Koronas-Foton on Feb. 20, 2009, during a test of its science instruments on the 320th orbit around the Earth:

The bootom region of the Sun's corona imaged at 18:27:42 UT. Click to enlarge. Credit: FIAN

A transitional region of the Sun's corona imaged at 18:28:42 UT. Click to enlarge. Credit: FIAN

The outer region of the Sun corona imaged by Koronas-Foton at 18:34:42 UT. Click to enlarge. Credit: FIAN