Wednesday, December 27, 2017

Zenit Rocket Launches AngoSat-1 but Ground Control Loses Contact with the Satellite

Zenit rocket launches AngoSat-1 on December 26. Photo Credit: Roscosmos

A Russian-Ukrainian Zenit rocket was launched on Tuesday, December 26 with the aim of delivering into orbit Angola’s first satellite, known as AngoSat-1. However, it appears that the contact with the spacecraft was lost after deployment into space. 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 marks the first Zenit flight in over two years when it orbited the Elektro-L No.2 weather satellite for Roscosmos. The rocket returned to flight despite the fears that the Russian-Ukrainian conflict, which started in 2014, would kill any joint efforts of these two countries.

The cooperation between Roscosmos and the Angolan government regarding AngoSat-1 dates back to 2009 when a contract was inked to developed 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 liftoff was later moved to November 2017 and finally postponed by one month.

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

Since the start of December, the engineers were busy conducting checkouts of 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.

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 north-eastern direction. 

Zenit’s first stage powered the rocket 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+7:10 minutes. 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 a goal of inserting the AngoSat-1 spacecraft into the targeted geostationary orbit, inclined 14 degrees East.

However, Russian media outlets, including the TASS state-run press agency, report that contact with the satellite was lost when its solar arrays began to unfold after the deployment into space.

"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.

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

AngoSat-1 will deliver television broadcasting and telecommunications services within the territory of the Republic of Angola, as well as the entire African continent. Angolan government hopes that the AngoSat-1 will expand satellite communications services, internet access, radio, and television. 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-2SB rocket (also known as Zenit-3F or Zenit-3SLBF) used for the Tuesday’s launch was designed by the Yuzhnoye Design Office of Ukraine. The 196 feet (59.6 m) tall booster is 13 feet (3.9 m) in diameter. The rocket has a total mass of 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 and one RD-8 engine.

For Tuesday’s mission, the Zenit rocket was used in configuration with the Fregat-SB upper stage. This stage uses one S5.92 engine and is 4 feet and 11 inches (1.5 m) long, with a diameter of 11 feet (3.35 m). 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. Therefore, Russia ends this year in second place, behind U.S., when it comes the total number of launches for 2017.

Next Russian launch is currently scheduled for late January 2018, when a Soyuz-2.1a rocket will lift off from Vostochny Cosmodrome to send four satellites into orbit.


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