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Elektro-L4 completes meteorological constellation In the first Russian orbital launch attempt of 2023, a Proton rocket delivered the long-delayed Elektro-L No. 4 meteorological satellite into the geostationary orbit giving Moscow a global view of the world weather for the first time. The liftoff took place as scheduled on February 5 from Baikonur Cosmodrome in Kazakhstan.
Elektro-L No. 4 mission at a glance:
Elektro-L No. 4 satellite during processing at NPO Lavochkin. From the outset of the Elektro-L program in the early 2000s, the constellation was intended to include three satellites. Separated by around 120 degrees from each other in an orbit 36,000 kilometers away from Earth, the group could provide a nearly complete view of the Earth's globe and its cloud cover. However, Roskosmos had never been able to operate three weather satellites simultaneously. The first Elektro-L, launched in 2011, failed in October 2016, at the half point in its operational life span and only less than a year after the second satellite was launched in 2015. The third Elektro-L would not reach orbit until 2019, so only two satellites have operated in orbit from 2020 to 2023. If the fourth launch in 2023 goes as planned and two older satellites continue surviving in orbit, Roskosmos will finally get a complete Elektro-L constellation. This particular satellite will focus on the Pacific region. Along with Elektro-L No. 4, the Elektro-L No. 5 satellite was also added into the program, with both launches initially expected in the first half of the 2010s. Originally, the fourth and fifth satellites were both intended for replacing the earlier satellites, before a more advanced trio of the spacecraft, known as Elektro-M, could be introduced in 2019 and 2020, according to plans circa 2014. By 2017, the launches of Elektro-L No. 4 and No. 5 were postponed until 2021 and 2022, respectively. In October 2018, NPO Lavochkin said that the fourth and fifth spacecraft would have to be "delivered" to the launch site in November 2021 and 2022, respectively, implying that their actual launches could shift to 2022 and 2023. The manufacturing of hardware for the Elektro-L No. 4 was reported in active phase in 2020, but the assembly of the satellite was only completed in 2022, when the tests of the fully integrated spacecraft could finally begin. Elektro-L No. 4 was reported returning to its manufacturing and assembly facility of NPO Lavochkin on Nov. 10, 2022, after a nine-day period of thermal-vacuum tests at NITs RKTs center. At the time, the spacecraft was yet to undergo mechanical, vibration, propulsion and integrated testing before its shipment to Baikonur Cosmodrome for launch, NPO Lavochkin said. According to unofficial sources at the time, the launch of the spacecraft had already slipped to 2023 by that time. After final tests and assembly at the manufacturer, Elektro-L No. 4 was delivered to Baikonur Cosmodrome on Dec. 27, 2022, to prepare for launch on a Proton-M/Block DM-03 rocket in February 2023. On Jan. 16, 2023, the TsENKI infrastructure division at Roskosmos announced that the fueling of Elektro-L4 had been completed after a four-day operation, after which the satellite was delivered to a processing facility at Site 31. Here it was encapsulated under the payload fairing, after which the resulting upper composite was transferred to Site 92A-50 for integration with the Proton rocket. The assembly was completed on February 1 and the launch vehicle was rolled out to Pad 24 at Site 81 on the morning of Feb. 2, 2023. Elektro-4L launch profile
The Proton-M/Block DM-03 rocket carrying Elektro-L4 satellite lifted off from Pad No. 24 at Site 81 in Baikonur on Feb. 5, 2023, at 12:12 Moscow Time (4:12 a.m. EST). Propelled by six RD-276 engines, the first stage boosted 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 around 123 seconds into the flight (L+123.79 seconds). 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 around five minutes 36 seconds after launch (L+335.77 seconds). 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, the payload fairing protecting the satellite from aerodynamic loads in the lower atmosphere split into two halves and dropped away five minutes and 49 seconds into the flight (L+349.14 seconds). The third stage fired its main engine until around 9.5 minutes into the flight (L+584.04 seconds). 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 steering engine cutoff, the payload section, including the Block DM-03 upper stage and the Elektro-L4 satellite separated into a suborbital trajectory nine minute and 45 seconds after liftoff. The third stage was expected to reenter the atmosphere and any of its surviving debris to fall into the Pacific Ocean. 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 44 seconds after liftoff. The maneuver, lasting slightly more than a minute, was designed to insert the stage and its payload into an initial parking orbit around the Earth. Its planned perigee (lowest point) was to be 175.5 kilometers and its apogee 208.8 kilometers from the Earth's surface. The stack was timed to fly passively around the planet for nearly one full orbit. The main engine of Block DM-03 then re-started one hour 12 minutes and 59 seconds after liftoff and fire for around eight minutes. The maneuver was designed to stretch the orbit into an ellipse with an apogee near the altitude of geostationary orbit at 35,487.4 kilometers above the Earth's surface. At the same time, the perigee increased to 251.8 kilometers. The space tug and its cargo had to climb passively away from Earth for more than five hours. Upon reaching the apogee of the transfer orbit six 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 around 400 kilometers lower than the 36,000-kilometer geostationary orbit. The maneuver was designed to cause the satellite to slowly drift in the easterly direction relative to the Earth's surface, before its own propulsion system would be used to slightly boost its orbit so that its orbital period matches the 24-hour rotation of the Earth around its axis and, as a result, the satellite appears "hanging" in the sky for an observer on Earth. The third maneuver of the upper stage was also designed to tilt 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 and thus to save propellant. Just one minute after the completion of the third engine burn, Block DM-03 released Elektro-L4 into its planned orbit six hours 37 minutes and 50 seconds after liftoff from Baikonur. The satellite was expected to eventually operate in geostationary orbit over a point 165.8 degrees East longitude over the Equator. According to the US military, by Feb. 24, 2023, Elektro-L4 raised its orbit, apparently reaching its planned altitude:
On March 10, 2023, Roskosmos confirmed that the spacecraft had reached a vicinity of its operational position at 165.8 degrees East longitude and began producing imagery. According to Roskosmos, Elektro-L4 transmitted its first image of the Earth to a ground station in Khabarovsk on March 10, 2023, at 04:00 Moscow Time and the satellite was declared operational on May 30, 2023, after a series of tests. This was the first time Russia possessed a complete meteorological network in the geostationary orbit with a global coverage. At the time, Elektro-L2 operated at 14.5 degrees West longitude and and Elektro-L3 worked at 76 degrees East longitude over the Equator, Roskosmos said.
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