|Spektr-RG launch scrub
The initial attempt to launch the Proton rocket with the Spektr-RG observatory on June 21, 2019, had to be cancelled due to a technical problem discovered during tests on the launch pad in a battery of the upper stage. It forced to postpone the mission until July 12, 2019. However, an issue with rocket insulation forced another 24-hour delay to July 13.
Launch attempt of the Spektr-RG mission on June 21, 2019, at a glance:
The liftoff of the Proton-M/Block DM-03 rocket, carrying the Spektr-RG satellite, was originally scheduled for June 21, 2019, at 15:17:14 Moscow Time (12:17 UTC, 8:17 a.m. EDT) from Pad 24 at Site 81 in Baikonur Cosmodrome. The payload section, including the Block DM-03 upper stage and the Spektr-RG satellite was scheduled to separate from the third stage at 15:26:57 Moscow Time, Roskosmos said.
According to the plan, the entire process of the orbital insertion was to last 1 hour 59 minutes 55 seconds and would conclude with the separation of the Spektr-RG spacecraft from its upper stage at 17:17:09.1 Moscow Time (14:17 UTC, 10:17 a.m. EDT) on June 21.
However several hours before the planned liftoff, Russian media reported that the mission had faced at least a 24-hour delay due to a technical problem with the spacecraft. In its official statement, published at 08:26 Moscow Time on June 21, Roskosmos announced only an unspecified technical issue which had required to postpone the launch to a backup date. (The next backup opportunity was available on June 22.)
However, the RIA Novosti news agency, quoting multiple sources within the industry, reported that pre-launch checks had revealed a discharged battery (known as KhIT) aboard the Spektr-RG satellite. The issue was too serious to be resolved in 24 hours and the next launch opportunity would not come until July 12.
A delay beyond 24 hours would require removing the launch vehicle from the pad and returning it to the assembly building. In the meantime, the official certification of the Proton rocket for launch is reportedly expiring in the middle of this year.
According to the TASS news agency, the State Commission overseeing the flight was expected to review the situation after 09:00 Moscow Time, however no official updates were issued for the next nine hours. The Interfax then reported that a meeting of the State Commission was postponed until 15:00 Moscow Time. Around 17:00 Moscow Time, industry sources reported that there would be no launch attempt on June 22.
In the meantime, the Moskovsky Komsomolets newspaper reported that the problem with the power source had been discovered at least a day earlier, but the entire Spektr-RG project team at the launch site was kept in the dark until hours before the planned liftoff, in order not to interfere with Vladimir Putin's annual press-conference on June 20. According to the paper, the battery was accidentally activated on the launch pad ahead of the scheduled time, leading to its drainage before the flight.
At 18:30 Moscow Time, Roskosmos confirmed the delay of the mission until July 12. The official statement said that "during the final phase of the pre-launch processing of the Spektr-RG spacecraft, a deviation had been discovered in the implementation of the planned sequence for the activation of one of the single-use chemical power sources."
At the launch site, Deputy Director General for Space Systems at Roskosmos Mikhail Khailov told reporters that a day after the June 19 test run of the readiness for launch, known as KNSG (for Kontrolny Nabor Startovoy Gotovnosti), specialists discovered that one of the power sources had been activated earlier than prescribed in the design documentation. According to Khailov, the power source was on the spacecraft, but industry sources pointed out that 9ER-type batteries (built by the Orion-KhiT company, based in Novocherkassk, in the Rostov Region of Russia) are located on the Block DM-03 stage. (Non-rechargeable batteries are normally used on rockets and their upper stages rather than on spacecraft, because upper stages operate only for a short period of time and don't need recharge.)
In any case, the accidental activation of the battery led to powering up heaters aboard the Spektr-RG spacecraft, which prematurely drained the non-reusable power source. (Normally, the heaters would receive power from the batteries of the upper stage during the two-hour orbital insertion process, before the spacecraft would separate from the upper stage and switch to its own batteries, which can be re-charged from solar panels, scheduled to deploy shortly after the separation.)
According to a poster on the online forum of the Novosti Kosmonavtiki magazine, the KNSG test simulates pre-launch operations until the moment of liftoff, however, according to the launch sequence, the heating of the spacecraft is programmed to be initiated two seconds after the liftoff. The probable reason for the unplanned activation of the battery is that the test personnel missed the fact that after the completion of the KNSG test run, the flight control computer aboard the upper stage does not quit instantly and, as a result, can still issue commands according to the pre-programmed sequence as late as seven seconds after the liftoff. The question still remains why it took the launch personnel around 24 hours, until June 20, to notice the activation of heaters aboard the spacecraft.
The next available launch window on July 12, 2019, also includes a backup liftoff opportunity on July 13. It would take around four days to return the rocket to the assembly building, separate the payload section, remove the payload fairing before specialists could replace the battery. According to industry sources, the removal of the spacecraft from the upper stage would not be necessary.
The return of the rocket to the assembly building was planned for June 22, 2019, according to RIA Novosti.
The rollout of the Proton with Spektr-RG to the launch pad on June 14. Following the scrub on June 21, the rocket had to be returned to the vehicle assembly building 92A-50.
As of July 1, the battery aboard the vehicle was successfully replaced, thanks to the fact that it was located on the open truss at the upper end of the Block DM-03 stage and it was possible to access it, while the payload section remained in horizontal position. If the spacecraft/upper stage stack had to be rotated vertically and placed into its processing rig for the full access, the personnel would not be able to meet the deadline for the new launch attempt on July 12, an industry source said.
As of July 8, the rollout of the launch vehicle to the launch pad was scheduled for July 9 for an abbreviated countdown and the new launch attempt at 15:31 Moscow Time on July 12. According to Roskosmos head Dmitry Rogozin, the rollout of the vehicle began in Baikonur at 04:30 Moscow Time and the State Corporation officially confirmed that the rocket had been installed on the launch pad.
On the morning of July 11, Roskosmos announced that during the final tests on the pad, specialists had discovered a problem with the launch vehicle, which required additional time to resolve. The issue will be reviewed at the meeting of the State Commission at Baikonur, where the decision would be made about the launch during the primary or backup window, Roskosmos said.
In the evening Moscow Time, Roskosmos issued another statement, saying that the pre-launch operations and the work to resolve issues with the vehicle would continue until the meeting of the State Commission then planned on the morning of July 12. The decision about the launch (at the originally scheduled time) or the delay until a backup date will be made at that meeting, Roskosmos said.
The commission met in Baikonur at 04:00 Moscow Time on July 12, and around three hours later, Roskosmos announced that the launch had been postponed until July 13. The postponement to a backup date was "due to the necessity for experimental confirmation from the specialists of Moscow-based manufacturer of the Proton-M launch vehicle of a technical solution to resolve the technical problem in one of the systems of the launcher," Roskosmos said.
According to the State Corporation, the final decision about the possibility of the launch would be made on the morning of July 13 based on the reports from the technical management to the members of the State Commission.
According to an industry source, the technical problem Roskosmos had referred to was in the insulation between the second and third stage of the launch vehicle. It was fixed with a special glue which needed five hours to cure. With that work successfully completed before the end of the day on July 12, the decision to go ahead with the fueling and launch on the morning of July 13 was expected to be a formality, an industry source said.
On July 12, Roskosmos published a routine announcement about the upcoming live broadcast of the launch on July 13 and on the morning of July 13, Roskosmos confirmed that the meeting of the State Commission had approved the fueling and launch of the mission at 15:30:57 Moscow Time on July 13.
After the successful launch, a poster on the web forum of the Novosti Kosmonavtiki magazine hinted that during the return of the Proton rocket from the launch pad to the vehicle assembly building back in June, the pressurization line of the oxidizer tank in the second stage of the launch vehicle had shown a pressure drop. The leak was serious enough to consider urgent air delivery of a replacement booster. However, the processing team resorted to welding the leak inside the assembly building and initial tests showed that the problem had been resolved. However, after the return of the rocket to the launch pad on July 9, the leak reappeared and its further welding on the launch pad was deemed impossible.
The management reportedly discussed returning the rocket back to the assembly building once again and postponing the mission for an indefinite period of time, which would also require to certify the rocket for flight past its warranty date and to re-program its flight sequence for the new launch window. Instead, an (improvised) solution was devised using some kind of sealant. Ground tests apparently confirmed that the fix would work, enabling flight officials to authorize the launch on July 13.
Another industry source then confirmed that version of events to the editor of this web site, adding that a special polymerizing glue and tape were used to seal the leak. The material had previously been approved for that type of function, but the reliability of the seal required during the launch had to be confirmed on special prototypes quickly fashioned in Moscow under a considerable time pressure. Ultimately, mission managers had to take responsibility for the proposed solution, by signing off on the official documentation clearing the vehicle for flight, a source said.
Click to enlarge. Credit: Roskosmos
Click to enlarge. Credit: Roskosmos
Block DM-03 with the Spektr-RG observatory is being prepared for launch on June 5, 2019. Click to enlarge. Credit: Roskosmos
The Proton rocket with Spektr-RG is erected on the launch pad on June 14, 2019. Click to enlarge. Credit: Roskosmos
The Proton rocket with Spektr-RG shortly after arrival at launch pad on June 14, 2019. Click to enlarge. Credit: Roskosmos
The propulsion system of the Block DM-03 upper stage will be responsible for two most critical maneuvers of the mission. Click to enlarge. Credit: Roskosmos
Proton with Spektr-RG returns to the launch pad on July 9, 2019. Click to enlarge. Credit: Dmitry Rogozin