Saturday, January 28, 2017

Arianespace Successfully Launches Hispasat 36W-1, Pushes Soyuz to Its Limits

Soyuz lifts off for its milestone first mission to geostationary transfer orbit (GTO) from the Spaceport in French Guiana. Flight VS16. Hispasat 36W-1. Credit: Arianespace

Nailing the opening of an instantaneous launch window, a Russian-built Soyuz ST-B lifted off from the Guiana Space Centre in French Guiana for Arianespace on a mission to deliver the Hispasat 36W-1 telecommunications satellite to a geostationary transfer orbit (GTO).

Flight VS16, the designation for this particular launch, lifted off from the South American space complex at 8:03 p.m. EST on Jan. 27, 2017 (01:03 GMT on Jan. 28, 2017) and marks the first mission to a geosynchronous orbit for a Soyuz from French Guiana.

“This flight once again demonstrates the availability and flexibility of Arianespace’s launch vehicle family at the service of our customers,” said Stephane Israel, the CEO of Arianespace, while at the spaceport.

The core stage’s RD-108A engine, along with the RD-107A engines on the four side boosters, ignited approximately 10 seconds before liftoff as the turbopumps spooled up to flight speeds. Once engines were at full output, delivering 932,000 pounds (4,146.5 kilonewtons) of sea-level thrust, the hold down arms retracted as the vehicle began its climb from the pad.

With the Hispasat satellite tipping the scales at 7,055 pounds (3,200 kilograms) and being at the top end of the Soyuz’s GTO capability, the rocket’s ascent started a bit slow.

The Soyuz began to build speed as the liquid oxygen (LOX) and rocket-grade kerosene (RP-1) propellant was consumed, lightening the vehicle in the process. Not long before booster separation, the rocket exceeded the speed of sound (Mach 1) and encountered the greatest atmospheric loads on the vehicle, also called “max Q”.

Approximately two minutes after lifting off, and with their propellant exhausted, the four side boosters separated from the core stage. When they separated, the four boosters appeared to form a cross as they performed a flipping and tumbling maneuver as they free-fell to the Atlantic Ocean below. This aerial display is called the Korolev Cross in homage to Sergei Korolev, the inventor of the R-7 rocket, a precursor to the Soyuz.

Now being powered solely by the core stage’s RD-108A engine, the vehicle continued building speed and altitude. Once above the atmosphere, the protective payload fairing was jettisoned approximately three and a half minutes after liftoff.

The Soyuz’s second stage – or third, depending on how the boosters are classified – began to fire its RD-0124 while still attached to the core stage, an operation known as “hot staging”, and separated approximately 4 minutes, 45 seconds into flight.

Hot staging negates the need for separation motors in the core stage, which can decrease the complexity of the staging process, and has been a mainstay of much of the Russian spaceflight industry for 60 years.

The vehicle and its payload continued to build speed as the stage burned its LOX and RP-1 propellant for nearly five minutes before the Soyuz’s final stage, the Fregat-MT, separated and ignited.

The Fregat was now tasked with completing the delivery of the Hispasat 36W-1 satellite to the proper GTO. To do this, the stage’s S5.92 engine, generating 4,460 pounds (19.85 kilonewtons) of thrust, operated for nearly 19 minutes.

Following a nearly five-minute ballistic coast phase, the Hispasat 36W-1 telecommunications satellite separated from the Fregat.

Over the following hours and days, the satellite will unfold its solar panels and deploy its antenna reflectors.

The satellite will slowly raise its orbit with its onboard chemical engine and will take up its position at 36 degrees West longitude to provide telecommunication services for Europe, South America, and the Canary Islands.

Once Hispasat 36W-1 enters service, it will mark an important evolution in Hispasat’s business operations.

“Hispasat 36W-1 is not only the first mission of the new SmallGEO platform, but also incorporates an advanced regenerative payload that will provide the satellite with greater flexibility and signal quality thanks to its reconfigurable antenna and on-board processor, thus improving the telecommunications services it will provide to its clients,” said Hispasat’s CEO, Carlos Espinós, in a release issued by the company.

This was the seventh satellite sent to space by Arianespace for Hispasat since 1992 – more than 60 percent of the company’s satellites currently in operation.

“I want to thank Arianespace’s work, which – as always – has been done with excellence,” Espinós said.

The successful launch of Hispasat 36W-1 was the first launch of Arianespace’s 2017 manifest.

Arianespace will have only a brief respite before their next scheduled mission – the launch of two communications satellites – which will fly atop an Ariane 5. Liftoff is scheduled for Feb. 14, 2017, during a launch window that extends from 4:39 p.m. to 6:05 p.m. EST (21:39 to 23:05 GMT).

Written by: Curt Godwin
Original source: spaceflightinsider.com

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