Spaceflight Insider

Sentinel-2B satellite set for launch atop European Vega rocket

Vega_VV01 Arianespace European Space Agency image posted on SpaceFlight Insider

Arianespace is preparing to launch the Sentinel-2B Earth-observation satellite atop a Vega rocket. Image Credit: Arianespace / ESA

Arianespace, a France-based multinational commercial launch provider, is in the final stages of readying its Vega rocket to send the Sentinel-2B Earth-observation satellite into a Sun-synchronous orbit (SSO).

The smallest member of Europe’s stable of launch vehicles is set to take flight at 8:49 p.m. EST March 6, (01:49 GMT March 7), 2017, from the Guiana Space Center in the South American country of French Guiana.

The rocket

Vying for its first launch of 2017, and its ninth overall since its 2012 debut, Arianespace’s Vega rocket has been tapped to deliver the 2,491-pound (1,130-kilogram) Sentinel-2B satellite to orbit. Unlike its larger Soyuz and Ariane 5 siblings, Vega is optimized to carry relatively small payloads to low-Earth orbit and has no stated capability to deliver a payload to geostationary transfer orbit.

Vega is unique among its European launch family in that all of its propulsion elements are solid-fueled. All three of its stages use the same hydroxyl-terminated polybutadiene (HTPB) 1912 mixture.

Although significantly less efficient than liquid propellant, solid fuels greatly simplify propulsion elements and can be stored for long periods of time.

Vega’s first stage is the P80 solid rocket motor (SRM). At almost 10 feet (3 meters), it has the same diameter as the solid-fueled boosters used on the Ariane 5 and nearly the same length of a single segment of that booster. The first stage provides 677,799 pounds (3,015 kilonewtons) of thrust at liftoff and burns for nearly two minutes.

Both the second and third stages use variants of the same 6.23-foot (1.9-meter) diameter Zefiro SRM. Vega’s second stage, the Zefiro 23, consumes 52,500 pounds (23,814 kilograms) of solid fuel during its 78-second burn time and provides up to 251,786 pounds (1,120 kilonewtons) of vacuum thrust.

Vega’s third and final stage is the Zefiro 9 SRM. Although smaller than its first and second stage cousins, it burns longer and provides 71,264 pounds (317 kilonewtons) of thrust for its two minutes of operation.

All three SRMs are manufactured from a carbon filament and epoxy casing, greatly lessening the mass of the rocket.

The payload

Sitting atop the 98.1-foot (29.9-meter) tall Vega is the Sentinel-2B (S2B) satellite.

Built on the Airbus Defence and Space AstroBus-L spacecraft bus, S2B is an Earth-observation satellite that will monitor land masses and coastal areas. It will have a particular focus on collecting vegetation and pollution data.

The spacecraft tips the scales at 2,513 pounds (1,140 kilograms) and is designed to have an on-orbit lifetime of at least seven years.

It will orbit at an altitude of 488 miles (786 kilometers) in SSO and will be inclined 98.57 degrees to the equator. In this orbit, the satellite will pass over the same spot on Earth’s surface at the same local solar time, providing consistent lighting angles for observation.

The satellite will have a resolution of 32.8, 65.6, and 196.9 feet (10, 20, and 60 meters) in 180-mile (290-kilometer) wide swathes with imagery covering 13 different spectral bands.

The Sentinel series of satellites is part of Europe’s Copernicus environmental monitoring program. S2B will be the fourth in the family and will join its Sentinel-2A sibling, orbiting 180 degrees apart, to provide full Earth coverage every five days.

“With two highly sophisticated satellites the Sentinel-2 mission will reach its full capability,” said Nicolas Chamussy, Head of Space Systems at Airbus, in a release issued by the company.


Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.

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