EgyptSat-A enters orbit after a close-call Soyuz launch
Almost five years after the original short-lived mission of a compact observation satellite built in Russia for the government of Egypt, a Soyuz-2 rocket lifted off on Feb. 21, 2019, carrying a replacement bird dubbed EgyptSat-A. However, the launch vehicle's third stage experienced an anomaly, leaving its payload some 60 kilometers lower than planned. Fortunately, once again, the Fregat space tug saved the day by automatically extending its own maneuvers and delivered the satellite into its planned orbit.
The EgyptSat-A mission at a glance:
What is known about EgyptSat-A
As a compensation for the premature loss of the EgyptSat-2 observation satellite in April 2015, the Russian firm RKK Energia agreed to build a new spacecraft, at least partially using the $75-million insurance payment resulting from the ill-fated mission. According to the Interfax news agency, the SK Sputnik company, which ensured the EgyptSat-2 launch, lost it license in 2016 and no other insurance provider agreed to cover the risk associated with the second launch attempt worth around $100 million.
In October 2015, the head of RKK Energia Vladimir Solntsev said that the company had come close to signing a contract for the development of the second satellite, the technical specifications for the future spacecraft had been in the process of formulation and the settlement with the insurers of the original failed launch had been almost completed.
In May 2016, Solntsev publicly confirmed that his company had already signed a contract for the development of a replacement for the failed EgyptSat-2.
On July 28, 2016, RKK Energia announced that it had formulated a design of the EgyptSat-A satellite for Egypt. The company quoted its Designer General for Automated Space Systems Igor Frolov as saying that during a recent meeting at the corporation, all the contractors involved in the project had confirmed their readiness to the supply necessary components for the implementation of the project.
According to RKK Energia, the newest version of the EgyptSat-2 satellite would be equipped with a more capable optical-electronic imaging system, upgraded flight control computers, a high-speed radio-transmission system and more efficient solar panels.
Various improvements would expand the observational capabilities of the satellite and increase the accuracy of geographical correlation of the resulting images to the mountainous terrains, RKK Energia said.
The spacecraft also was promised to carry a higher share of Russian-built components than had its predecessor, including X-band transmitters which had previously been tested aboard the International Space Station, ISS.
In August 2018, Head of Roskosmos Dmitry Rogozin said that based on the performance of the EgyptSat-A, the State Corporation might make a decision to develop a similar satellite for the Russian space program. Original plans called for a total of three satellites in the EgyptSat family, each with increased capabilities.
Preparations for the EgyptSat-A mission
As with the previous EgyptSat mission, the preparations for the launch of the EgyptSat-A mission were mostly secret and no photos of the actual spacecraft had been released by the time it had reached the launch pad.
The launch of EgyptSat-A was originally planned from the military site in Plesetsk in October 2018 on an unused Soyuz-2-1b rocket, which rolled off the production line in October 2012 for a GLONASS mission. The operational warranty for the launch vehicle was reportedly expiring in April 2019 and it was re-assigned for the EgyptSat-A mission.
However, the launch then had to be moved to a "different site due to organizational problems," according to Interfax, which is official speak for wrangling over money, probably between RKK Energia and the Ministry of Defense. In any case, the mission had to be re-located to Baikonur, from where access to the polar orbit chosen for the EgyptSat-A mission required to rent rarely used impact sites from the government of Kazakhstan to drop the spent boosters of the first stage.
Various industry sources reported that the launch had originally been planned for Nov. 22, 2018, but by September of that year, the mission was postponed until Dec. 27, 2018. The Soyuz rocket for the mission arrived at Baikonur around the middle of October 2018, but by the beginning of December 2018, the launch was postponed until Feb. 7, 2019, and by the end of 2018, the mission slipped again until February 21 of the same year. The delays were apparently related to the payload, because in order to launch on February 7, EgyptSat-A had to be at the launch site on Jan. 20, 2019, but it did not make it to Baikonur until the beginning of February 2019. According to the Kommersant newspaper, the reshuffles in the EgyptSat-A mission required to push the launch of the Progress MS-11 cargo ship to the ISS from February 8 to March 28, 2019.
Also, after finding cracks in the pressurization lines of the Fregat upper stage slated to launch first OneWeb satellites from Kourou, an identical vehicle for the EgyptSat-A mission had to undergo extra checks. After confirming the absence of problems, the stage was shipped to a fueling station in Baikonur on February 4.
EgyptSat-A launch scenario
Unlike the original EgyptSat-2 satellite launched into an orbit inclined only 51.6 degrees toward the Equator, the fresh bird in the series was designed to be inserted into a near-polar orbit, which extends from North Pole to South Pole and whose orbital plane is perpendicular to the plane of the Equator. As a result, the spacecraft was to be able to observe practically the entire planet as the Earth rotates below it. In contrast, the previous satellite from the EgyptSat-2 series could only cover areas between 51.6 latitude North in the Northern Hemisphere and 51.6 degrees South latitude in the Southern Hemisphere, which included the Egyptian territory, but did not cover vast regions of the planet in both hemispheres.
In order to reach a polar orbit from Baikonur, the Soyuz rocket had to ascend along an unusual ground track, taking the mission almost directly north from the launch site, instead of the traditional eastern direction. The rocket flew over the Aktyubinsk and Kostanai Regions of Northern Kazakhstan and then follow across the Russian territory from south to north along the Ural Region. A similar ascent profile was used during Soyuz launches with the European MetOp satellites. That trajectory results in the impact of the four boosters of the first stage in the Irgiz and Dzhangeldin Districts in Northern Kazakhstan. In the meantime, the satellites' payload fairing (protecting it from aerodynamic loads during first minutes of the flight through the atmosphere), as well as the rocket's second stage and the three segments of the aft section from the third stage would be dropped in a 2,000-square-kilometer area centered in Krasnovishersk District on the border between the Perm Region and the Sverdlovsk Region in the Urals.
The third stage of the rocket, which was scheduled to complete its firing less than 1o minutes after the liftoff and just short of reaching the orbital velocity, was expected to reenter the atmosphere and fall in the 199 by 35-mile elliptical area in the Greenland Sea between Spitsbergen and Greenland. A warning to air traffic extending from February 21 to February 24 was issued for the area several days before the scheduled liftoff.
In another major difference from the original EgyptSat-2 launch, the three-stage Soyuz rocket was equipped with an additional Fregat upper stage to insert EgyptSat-A directly into its operational Sun-synchronous orbit, something that required two engine firings. According to NPO Lavochkin, the Fregat developer, it was the 73rd mission for its space tug.
If everything went as planned, EgyptSat-A was to separate from the Fregat at 21:05 Moscow Time (1:05 p.m. EST) or one hour 18 minutes after the liftoff. The Fregat upper stage was then programmed to be deorbited over the Pacific Ocean between the coast of Mexico and Hawaii.
Following in-orbit testing of the spacecraft, the operational control over the mission was expected to be transferred to Egyptian specialists, Roskosmos said before launch.
Soyuz lifts off with EgyptSat-A and runs into trouble
The Soyuz-2 rocket, carrying EgyptSat-2A, was reported lifting off as planned, but ground tracking indicated that the third stage had left its payload in an orbit with a perigee some 60 kilometers lower than planned.
There was still some chance that the Fregat upper stage could compensate for the lack of velocity and altitude by automatically extending its own maneuvers, but ground controllers apparently had to wait for the Fregat/EgyptSat-A stack to reenter the communications range of Russian tracking stations to confirm the final orbit of the mission.
Soon after the scheduled completion of the flight, multiple reports, including an official statement from Roskosmos, confirmed the successful release of the satellite into its planned orbit at 21:04 Moscow Time and its normal communications with ground control. The spacecraft also deployed its solar panels.
However several hours after the EgyptSat-A launch, the OneWeb company announced an at-least-one-day postponement of its Soyuz mission previously scheduled for February 26 from Kourou, French Guiana.
In the meantime, EgyptSat-A was cataloged in a 652 by 657-kilometer orbit with an inclination 98.0 degrees toward the Equator.
On February 22, Roskosmos announced that Russian specialists working at the Egyptian mission control center had begun flight testing of EgyptSat-A and that all the systems aboard the spacecraft were functioning normally.
According to industry sources familiar with the investigation into the anomaly during the February 21 Soyuz launch, the available telemetry registered an emergency engine shutoff, known in Russian as AVD, as the 3rd stage of the rocket was completing its firing. The emergency command was issued based on the loss of pressure in the combustion chambers of the propulsion system. As a result, the emergency cutoff took place around six seconds prior to the so-called GK-3 command, which performs the nominal shutdown of the engine on the third stage. As a result of the premature cutoff, the rocket (and its payload) ended up on a trajectory with a perigee 57 kilometers lower than planned.
Fortunately, the flight control computers aboard the Fregat upper stage had detected the AVD command and determined that it had enough propellant for compensating the deficiency in velocity and altitude, as planned under such circumstances.
The computers aboard Fregat then commanded its separation from the third stage and the activation of its main propulsion system, which lasted 17 seconds longer than planned. The resulting transfer orbit turned out to be close to what was originally planned for the mission, with the exception of the longitude of the ascending node (the point, where the ground track of the orbit crosses the Equator from Southern to Northern Hemisphere of the Earth).
On February 22, Head of Roskosmos Dmitry Rogozin accused "unscrupulous" media of distorting information about the launch of EgyptSat-A, which he blamed for the postponement of the next launch of the Soyuz rocket scheduled in Kourou, French Guiana. Rogozin denied reports about the formation of an investigative commission into the incident.
In the meantime, according to posters on the web forum of the Novosti Kosmonavtiki magazine, investigators analyzed the telemetry from the Angosat-A launch and established that the loss of pressure in the engine had been caused by the premature consumption of liquid oxygen, which serves as an oxidizer for the kerosene fuel.
Specialists then turned to the ground processing documentation related to the propellant loading into the third stage and quickly discovered that specifications for the amount of propellant to be loaded aboard the booster had been switched between fuel and oxidizer, apparently due to a human error. As a result, the stage was loaded with insufficient amount of liquid oxygen and an excess of kerosene.
Under normal circumstances, the third stage was to receive 15.7 tons of liquid oxygen and 7.2 tons of kerosene.
At the same time, all ground systems for controlling and monitoring the fueling process, known as SIUZ and SDUZ, had been found performing as planned. The investigators transferred all the relevant information to the specialists preparing the following launch in French Guiana. Officials also implemented new measures for checking documentation during the pre-launch processing to eliminate the repetition of an incident, industry sources said.
A structure of the EgyptSat satellite: 1 - solar panels; 2 - instrument panel; 3 - aft bulkhead; 4 - body structure. Credit: RKK Energia
A Soyuz/Fregat rocket shortly after installation on the launch pad on Feb. 18, 2019. Click to enlarge. Credit: RKK Energia
To deliver the EgyptSat-A spacecraft into its polar orbit, the Soyuz rocket would have to head north from Baikonur.
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In March, an Egyptian web site published photos taken by a camera onboard the EgyptSat-A satellite, providing first evidence that it had functioned in orbit. Click to enlarge. Credit: Egyptian-Russian Foundation for Culture and Science