Proton launches Elektro-L3
Completing its operations in 2019, Proton rocket successfully flew its fifth launch of the year on December 24, delivering the Elektro-L No. 3 weather satellite. It was the third spacecraft in the Elektro-L series, even though only Elektro-L2 remained functioning in the geostationary orbit at the time.
Elektro-L No. 3 mission at a glance:
According to Vladimir Babyshkin, the head of the project at NPO Lavochkin, Elektro-L3 had a higher mass than previous spacecraft in the series due to switch from Zenit to Proton, allowing the full load of propellant aboard the satellite's Navigator service module.
The development of the third satellite in the Elektro-L series was given the final go ahead in 2012. Like the first and second Elektro satellites, Elektro-L No. 3 was designed for launch on a Zenit rocket, which Roskosmos ordered for the mission in March 2013. However, in February 2015, in the wake of the Russia's conflict with Ukraine, NPO Lavochkin announced that the third Elektro-L satellite would be switched from the Zenit to a Proton rocket.
At the time of the Elektro-L2 launch in December 2015, the third satellite was promised to fly at the end of 2016 or the beginning of 2017. In February 2016, RKS Corporation announced that its production factory, RKP, had completed calibration and testing of the multi-range scanning instruments which would be used aboard the satellite to produce images of the Earth.
However, in October 2016, Roskosmos said that the launch of the Elektro-L No. 3 satellite had been scheduled for the end of 2017. The main reason for this almost year-long delay was apparently related to the satellite's key instruments, which had to be upgraded based on experience with the preceding spacecraft.
By the middle of 2017, the third Elektro-L mission had to be postponed again, this time to the Fall of 2018. As of September 2017, the launch was scheduled for October 22, 2018. At the time, GKNPTs Khrunichev in Moscow was assembling a Proton-M rocket for the mission and RKK Energia in Korolev was working on the Block DM-03 No. 6L upper stage, with a completion date of September 30, 2018. However, sometimes after April 2018, the Elektro-L3 mission had to be delayed once again, to the second quarter of 2019.
By September 2018, the launch was pushed back yet again, this time to October 2019. At the time, the assembly of satellite was underway, but a number of technical issues still remained, even though they were deemed to be resolvable, industry sources said.
Elektro L3 enters final tests
A photo of the Elektro-L3 satellite released on Oct. 5, 2018.
On October 5, NPO Lavochkin announced that on September 3, the Elektro-L3 had been transferred to the checkout and test station, KIS, for final but non-integrated tests and confirmed that its launch was scheduled for October 2019. According to the company, all components of the spacecraft had been manufactured, including the service module and the payload module, except for the heliophysics instrument complex, GGAK. NPO Lavochkin promised the delivery of the GGAK payload in January 2019.
The October 5, a press-release quoted the head of NPO Lavochkin's directorate for meteorological projects Vladimir Babyshkin as saying that following tests at KIS, the satellite would be assembled in flight configuration at the company's experimental plant. The thermal control platform with the service system would be installed inside the body (of the service module) and the payload module would be installed on top of the service module. The specialists were also completing the installation of the onboard cable network and thermal protection system. After the completion of the assembly, the spacecraft would have to undergo integrated tests in the vacuum chamber.
Only after the installation of the GGAK payload, would the satellite enter acceptance tests, including electric tests, radio checks inside anechoic chamber and mechanical load tests, the announcement said.
On August 15, 2019, Elektro-L No. 3 was shipped from NPO Lavochkin to NITs RKP in Peresvet for vacuum testing, NPO Lavochkin said.
According to another press-release published by NPO Lavochkin on November 25, the final checks of the Elektro-L satellite included integrated testing in the vacuum chamber, electrical and vibration tests, as well as checks for electromagnetic compatibility of avionics in the anechoic chamber. In addition, the heliophysics payload was installed aboard the spacecraft and a number of mechanical checks were conducted, including test deployment of the solar panels and antennas of the spacecraft, measurement of clearances between the spacecraft and the launch vehicle payload fairing, calculation of the spacecraft's center of mass, mechanical loads measurements and checks of the propulsion system pressurization. Specifically for anechoic chamber tests, NPO Lavochkin manufactured a custom rigging system, which allowed deploying the satellite's high-gain antennas into operational position in the limited room of the test facility, the company said.
By December 14, 2019, Elektro-L3 was prepared for integration with the Block DM-03 upper stage featuring top and middle sections of the payload fairing (right) originally intended for the Zenit rocket.
The train carrying the Proton-M launch vehicle and the payload fairing for the Elektro-L3 mission departed the production plant at GKNPTs Khrunichev in Moscow for Baikonur during the night from October 31 to November 1, 2019. The same echelon also carried a full-scale mockup of the Briz-M upper stage intended for integrated tests of the new fueling station in Baikonur, Roskosmos said. The train reached Baikonur as planned, GKNPTs Khrunichev announced on November 11, 2019.
In the meantime, the Elektro-L3 satellite was shipped from NPO Lavochkin to Moscow's Sheremetievo airport, where it was loaded aboard an An-124-100 transport plane and, on November 25, 2019, the spacecraft was flown to Baikonur. According to the press-release published at the time, the launch of the spacecraft was scheduled for the end of December 2019.
On November 29, the Chief Designer Council overseeing the Elektro-L3 launch campaign met at RKK Energia and gave the green light to the fueling and final processing of the Block DM-03 upper stage for the mission, the company announced.
The launch vehicle with the spacecraft was rolled out to Pad 24 at Site 81 in Baikonur on December 21, 2019.
Elektro-3L launch profile
Propelled by six RD-276 engines, the first stage lifted the rocket off the pad and after a few seconds in vertical ascent, started turning east, firing for around two minutes.
The separation of the first stage took place at T+123.8 seconds into the flight. Moments before separation, the four-engine cluster of the second stage took over the powered flight, for the first few moments, firing through a lattice structure connecting two stages .
The second stage operated for three and half minutes and separated 5 minutes and 35.7 seconds after launch. Moments earlier the four thrusters of the RD-0214 steering engine on the third stage fired through special openings in the ring adapter connecting the second and third stage and immediately after the second stage dropped off along with the adapter, the main RD-0213 engine on the third stage joined in.
Seconds later, at T+5 minutes 49.1 seconds from launch, the payload fairing protecting the satellite from aerodynamic loads in the lower atmosphere split into two halves and dropped away.
The third stage fired its main engine until around 9.5 minutes into the flight. The four-nozzle steering engine of the stage continued operating for around 12 seconds longer to refine the speed of the vehicle to a precise parameter just short of orbital velocity. A fraction of a second after the third stage engine cutoff, the payload section, including the Block DM-03 upper stage and the Elektro-L3 satellite separated into a suborbital trajectory. The third stage was expected to reenter the atmosphere and any of its surviving debris were to fall into the Pacific Ocean.
Roskosmos confirmed that the payload section, including the upper stage and the satellite, had separated from the third stage of the launch vehicle 585 seconds after the liftoff and the Block DM-03 stage continued the ascent.
Space tug operations
After nearly six minutes in a passive ballistic flight, the Block DM-03 upper stage fired its main engine at T+15 minutes 45 seconds after liftoff.
The maneuver, lasting slightly more than a minute, inserted stage and its payload into an initial parking orbit around the Earth. Its planned perigee (lowest point) was supposed to be at an altitude of 175.5 kilometers and an apogee at 208.8 kilometers above the Earth's surface. The stack then flew passively around the planet for nearly one full orbit.
The main engine of Block DM-03 then re-started around one hour 13 minutes after liftoff and fired for around eight minutes. The maneuver stretched the orbit into an ellipse with an apogee (the highest point) near the altitude of geostationary orbit nearly 36,000 kilometers above the Earth's surface. The space tug and its cargo then climbed passively away from Earth for more than five hours. Upon reaching the apogee of the transfer orbit 6 hours 25 minutes and 19 seconds after liftoff, Block DM-03 fired its engine for the third time, for almost four minutes, to circularize the orbit at an altitude of 35,405.5 kilometers. The same maneuver also tilted the inclination of the orbit from the latitude of Baikonur to that of the Equator. The energy-hungry inclination change was intentionally conducted at the highest altitude to minimize the influence of the Earth's gravitational pull.
Just one minute after the completion of the third engine burn and six hours 37 minutes after leaving Baikonur, Block DM-03 released Elektro-L3 into its operational orbit.
In the post launch press-release, Roskosmos announced that the spacecraft had taken its planned location in the geostationary orbit and that the specialists of the Chief Operational Control Group, GOGU, had started flight testing of the satellite. The spacecraft was to eventually be stationed at its operational orbital position 165.8 degrees East longitude over the Equator, Roskosmos said.
After the launch, the Combined Space Operations Center, CSpOC, in the United States listed two objects associated with the mission, which represented Elektro-L3 and Block DM-03:
According to industry sources, after the initial separation from Block DM-03, the satellite maneuvered to begin a drift four degrees per day toward its operational position. Another orbit correction performed on January 6, 2020, reduced the drift rate to 1.3 degree per day. Finally, the third maneuver reduced the drift further to 0.11 degree per day.
On January 27, 2020, Roskosmos announced that Elektro-L3 was in-route to its operational position at 165.8 degrees East longitude and the technical phase for the integrated preparation of all onboard systems and ground services for obtaining meteorological information by the spacecraft would begin starting in February 2020. According to the State Corporation, all systems aboard the satellite functioned well.
On February 1, 2020, the satellite reached its planned position and a small engine firing stopped its further drift, allowing the mission control to begin activation and testing of its payloads, according to industry sources. Roskosmos confirmed the arrival of the satellite to its operational position on February 4.
On June 4, 2020, Roskosmos announced that the testing of the Elektro-L No. 3 satellite, deployed at 165.8 degrees East longitude, had been completed on May 31, 2020. "At this time, the transfer of the Russian satellite to the vicinity of the position 76 degrees East longitude has begun for the continuation of the flight tests," the press-release said. According to Roskosmos, the Elektro-L3 was expected to reach the planned position at the beginning of July 2020, where the Elektro L2 continued routine operations, before its own move to a new location.
On November 17, 2020, the meeting of the State Commission concluded that flight testing of the Elektro-3L satellite had been successfully completed and the spacecraft was recommended for the regular use at its operational position at 76 degrees East longitude along with the Elektro-L2 spacecraft deployed at 14.5 West longitude, Roskosmos announced.
Scenes at NPO Lavochkin showing the assembly of the Elektro-L satellite or one of its prototypes circa 2016. Credit: Roskosmos
A photo of the Elektro-L3 satellite published by Roskosmos on Nov. 25, 2019. Click to enlarge. Credit: Roskosmos
Elektro-L3 leaves NPO Lavochkin's assembly facility for Sheremetievo airport in November 2019. Click to enlarge. Credit: Roskosmos
The Elektro-L3 satellite was transported to Baikonur in November 2019. Click to enlarge. Credit: Roskosmos
Elektro-L3 is being integrated with the Block DM-03 upper stage around December 14, 2019. Click to enlarge. Credit: Roskosmos
Proton with Elektro-L3 rolls out to launch pad on December 21, 2019. Click to enlarge. Credit: Roskosmos
The upper composite of the Proton rocket with the Elektro-L3 satellite. Click to enlarge. Credit: Roskosmos
Proton with Elektro-L3 is being installed on the launch pad. Click to enlarge. Credit: Roskosmos
Proton with Elektro-L3 shortly after installation on the launch pad. Click to enlarge. Credit: Roskosmos
Proton lifts off with Elektro-L3 on December 24, 2019. Click to enlarge. Credit: Roskosmos
On February 7, 2020, Roskosmos published the first photo produced by Elektro-L3 satellite. Click to enlarge. Credit: Roskosmos