Spektr-RG faces more delays
The final assembly of the Russian-German X-ray orbital observatory hit a snag again, forcing a six-month postponement of its launch. In the meantime, preparations for launch bogged down during the first half of the year.
Spektr-RG project scientists and space officials inspect German-built eRosita telescope at NPO Lavochkin facility in February 2017.
On February 16, NPO Lavochkin, the prime contractor responsible for the development of the Spektr-RG spacecraft, hosted the first meeting of the project team in 2017. According to the company, the German side, which provided one of the two instruments for Spektr-RG, confirmed the successful completion of tests on the eRosita telescope after its delivery to Russia. The German instrument was then expected to undergo entry control by engineers from NPO Lavochkin and Moscow-based Space Research Institute, IKI. Both telescopes of the mission were then slated for electrical tests, which would clear the way for the final assembly of the flight-worthy observatory before its long-delayed launch then planned in March 2018.
However in the subsequent months, work on the Spektr-RG seemingly came to a standstill. During another meeting on May 16, the mission management broke the news that the launch of the Spektr-RG would have to be postponed for another six months from March to September 2018. The main reason for the delay was blamed on a production defect in a component, which prevented the on-time delivery of the onboard radio complex, BRK, for the spacecraft. The delivery of the crucial radio system from the Moscow-based RKS Corporation had been repeatedly promised within a month since the middle of the previous year but had been constantly delayed. Although the testing of the spacecraft could be conducted with a stand-in model of the BRK, the work on the telescopes had also remained stalled due to "missing documents," according to Russian officials. As often happens in international projects, translation of documents and language barriers slowed down the work.
In the official interview published on May 18 by TASS and Roskosmos, the head of NPO Lavochkin Sergei Lemeshevsky said, "In particular, it is necessary to re-program the onboard flight control system, because not everything was designed as planned on the eRosita telescope. In addition, it will be necessary to check the new software."
Industry sources explained that Lemeshevsky had referred to an issue discovered last fall during the integrated tests of eRosita. At the time, engineers realized that under some rare circumstances, a main controller failure could lead to the shutdown of the thermal control system in the telescope, if there was no reaction from onboard computers within a few hours. The German team proposed a minor software change in the satellite's flight control system, BKU, which would provide the necessary redundancy by turning the controllers off and on, if they did not respond in a normal fashion.
The software fix would also require some tests of the software after the integration of the eRosita telescope with the Spektr-RG spacecraft.
According to sources at NPO Lavochkin, eRosita also had problems sending scientific data via the BRK radio system during tests. The culprit was eventually traced to a misunderstanding between the Russian and the German team of the jointly agreed transmission protocol. The issue was resolved in April 2016 and the prototype of the eRosita telescope was successfully re-tested in conjunction with the spacecraft. Still, the problem pushed back the completion and testing of the BRK radio system, a source at NPO Lavochkin said. According to Russian sources, the assembly of the BRK was further complicated by organizational problems and by errors during the wiring of electronic boards of the system.
At the time, NPO Lavochkin also faced a 1.4-billion-ruble penalty from Roskosmos for its failure to deliver Spektr-RG on time in accordance with a contract signed in 2011.
Real reasons for the delay
At the May 16 event, the long-delayed delivery of the radio system, BRK, for Spektr-RG was now promised by June 15. In the meantime, a prototype of the BRK was installed on the spacecraft for final tests. In turn, these tests could only begin after the completion of entry inspections on both telescopes, which were not expected to finish until the end of May.
At the beginning of July, NPO Lavochkin hoped to resume electric tests of the spacecraft, this time with flight-worthy models of both telescopes and the operational BRK radio system. The delay in the BRK delivery would push the readiness of the spacecraft for launch until June 2018. However, the next available launch window for Spektr-RG dictated by ballistic conditions would not be available for a few more months, hence the new launch date in September 2018.
The cumulative delays in the project required to formally cut the guaranteed life span for the Spektr-RG telescope in orbit from seven years to 6.5 years.
On the bright side, the IKI team reported that the testing of the Russian-built ART-XC telescope had been completed on April 15.
On July 20, a joint team from NPO Lavochkin and the Max Planck Institute successfully attached the German-built eRosita telescope to the payload-holding truss, KNA, of the Spektr-RG spacecraft, NPO Lavochkin announced. In the next step of the assembly, the KNA truss would be moved to a clean room chamber for joint electrical tests with the Navigator service module. At the time, the launch of the spacecraft was still planned for October 2018, NPO Lavochkin said. (827)
To meet the October 2018 launch window for the Spektr-RG observatory, NPO Lavochkin implemented a three-shift, seven-day-a-week work schedule.
On the evening of December 18, the Russian-German team successfully completed integrated tests of the spacecraft, which included flight versions of the eRosita and ART-XC telescopes, as well as the Navigator service module. However, the troublesome BRK radio system was still represented by a qualification model.
The main radio system was fully available, but its backup set was still missing an electronics component known as Field-Programmable Gate Array or FPGA (sometimes abbreviated in Russian as PLIS), industry sources said. The particular system was built in the US and NPO Lavochkin was not able to directly obtain it due to export controls and had to consider redesigning the associated electronics. After a three-month review of the export license, the necessary component was delivered to Germany by the middle of December, but there it also needed an export permission from German authorities, which postponed its delivery to Russia to a period between the end of December 2017 and the beginning of January 2018.
A day after the completion of integrated tests, the Izvestiya daily quoted the head of the Spektr-RG project at NPO Lavochkin Vladimir Babyshkin as saying that continuing delays with the delivery of the BRK radio system required to postpone the launch of Spektr-RG from the end of 2018 to the 2019 window (which would be open from March to April). Industry sources confirmed that the preparations had been under increasing pressure, however, the most recent official schedule had still called for the launch of Spektr-RG in October 2018.
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General architecture of the Spektr-RG spacecraft as of 2017. Credit: NPO Lavochkin
An ART-XC telescope shortly after its delivery to NPO Lavochkin at the end of 2016. Click to enlarge. Credit: Roskosmos
The eRosita telescope shortly after its delivery to NPO Lavochkin in January 2017. Click to enlarge. Credit: Roskosmos
The KNA payload structure holding eRosita and ART-XC telescopes is being moved during tests at NPO Lavochkin circa July 2017. Click to enlarge. Credit: Roskosmos