Spaceflight Insider

Zenit rocket launches AngoSat-1 but ground control loses contact

Zenit-3F/Fregat-SB with AngoSat-1 atop

The launch of a Zenit-3F/Fregat-SB rocket with the AngoSat-1 spacecraft at 19:00 UTC on Dec. 26, 2017. Photo Credit: TsENKI / Roscosmos

A Russian-Ukrainian Zenit rocket was launched on Tuesday, December 26, 2017, with the aim of delivering into orbit Angola’s first satellite, known as AngoSat-1. However, it appears that contact with the spacecraft was lost after its deployment into orbit. The booster lifted off at 19:00 GMT (2:00 p.m. EST) from the Site 45/1 at the Baikonur Cosmodrome in Kazakhstan.

Tuesday’s launch marked the first Zenit flight in more than two years when it orbited the Elektro-L № 2 weather satellite for Roscosmos. The rocket returned to flight despite fears that the Russian-Ukrainian conflict, which started in 2014, would kill any joint efforts between these two countries.

Zenit-3F/Fregat-SB with AngoSat atop

The Zenit-3F/Fregat-SB launch with AngoSat-1. Photo Credit: TsENKI / Roscosmos

The cooperation between Roscosmos and the Angolan government regarding AngoSat-1 dates back to 2009 when a contract was inked to develope the satellite and launch it into orbit. Under the deal, which was implemented in 2012, the launch of AngoSat-1 was initially scheduled for 2016. However, the date of the satellite’s flight was later moved to Nov. 2017 and finally postponed by one month.

The pre-launch campaign started with the arrival of the AngoSat-1 at Baikonur on Nov. 16. Afterward, the spacecraft passed initial checkouts and inspections in order to make sure that it is ready to move forward with launch preparations.

Since the start of December, engineers were busy conducting checkouts of different parts of the Zenit rocket. The launch vehicle was finally assembled on December 19 and the rocket, with the satellite atop of it, was rolled out to the pad on December 24.

The launch

Firing its four-chamber RD-171M engine, the Zenit rocket thundered from the launch pad at exactly 19:00 GMT. The launch vehicle completed a short vertical climb before performing a pitch and roll maneuver in order to start heading in a north-easterly direction.

Zenit’s first stage powered the rocket’s flight for about two-and-a-half minutes, then it burned out and was detached from the launch vehicle. Next, the second stage assumed control over the flight, accelerating the rocket until T+7 minutes, 10 seconds. Meanwhile, five minutes and 22 seconds after launch, the payload fairing was jettisoned, unveiling the AngoSat-1 spacecraft.

Separation of the second stage occurred eight minutes and 37 seconds after liftoff, leaving the satellite attached to the Fregat-SB upper stage. This marked the start of a lengthy, nearly nine-hour trek with the goal of inserting the AngoSat-1 spacecraft into a targeted geostationary orbit, inclined 14 degrees East.

However, Russian media outlets, including the TASS state-run press agency, have reported that contact with the satellite was lost when its solar arrays began to unfold shortly after the spacecraft’s deployment into orbit by the rocket’s Fregat-SB upper stage.

“Experts from the Energia Space Corporation are analyzing the telemetry data provided by the AngoSat satellite in order to resolve the situation. Work is underway to restore contact with the satellite,” TASS informed.

The AngoSat-1 spacecraft

Under an agreement signed in 2009, AngoSat-1 was developed by RSC Energia – a Russian manufacturer of rockets and spacecraft. The satellite is based on RSC Energia’s Universal Space Platform (USP), weighs around 1.55 metric tons, and features two deployable solar arrays. It is equipped with 16 C-band and 6 Ku-band transponders; its designed lifetime is 15 years.

Zenit-3F/Fregat-SB with AngoSat atop

A Zenit-3F/Fregat-SB with the AngoSat-1 atop awaiting launch. Photo Credit: TsENKI / Roscosmos

If contact with AngoSat-1 is restored, it should provide television broadcasting and telecommunications services in the Ku-band within the territory of the Republic of Angola as well as C-band coverage over the entire African continent and southern parts of Europe.

The Angolan government had hoped that the AngoSat-1 would expand satellite communications services, internet access, radio, and television services. The Angosat project is part of Angola’s National Space Program, which aims to create of national competences in the field of satellite communications technologies.

The Zenit rocket

The Zenit-3F rocket (also known as Zenit-2SB or Zenit-3SLBF) utilized for this launch was designed by the Yuzhnoye Design Office of Ukraine. The 196 feet (59.6 meters) tall booster measures 13 feet (3.9 meters) in diameter. The rocket has a total mass of some 519 tons (471 metric tons) and is capable of delivering up to 4.4 tons (4 metric tons) into GTO.

The first stage of this launch vehicle uses one RD-171 engine, whereas the second stage features one RD-120 as well as one RD-8 engine.

For the AngoSat-1 mission, the Zenit rocket was used in configuration with a Fregat-SB upper stage. This stage uses a lone S5.92 engine and is 4 feet and 11 inches (1.5 meters) long, with a diameter of 11 feet (3.35 meters). The SB version is a variation of the Fregat-M with a block of drop-off tanks which makes increased payload capability possible.

Tuesday’s mission was the 84th Zenit flight overall, and the 13th liftoff from the Baikonur Cosmodrome in 2017. It was also the 20th Russian orbital mission this year (2017). Therefore, Russia ends this year in second place, behind the U.S., when it comes the total number of launches for 2017.

The next Russian launch is currently scheduled to take place in late January 2018 when a Soyuz-2.1a rocket is slated to lift off from Vostochny Cosmodrome to send four satellites into orbit.

Video courtesy of Телестудия Роскосмоса (Roscosmos TV)



Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.

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