Arianespace successfully launches two satellites atop Ariane 5 booster
Arianespace successfully sent the Astra 5B and Amazonas 4A satellites to orbit on Saturday, March 22 at 6:04 p.m. EDT (22:04 p.m. GMT). Lifting off from the Kourou, French Guiana spaceport, the two satellites were stacked one on top of the other inside their Système de Lancement Double Ariane (SYLDA) payload carrier. The flight, dubbed VA-216, had been scheduled to launch yesterday, however, weather conditions did not allow for the rocket to be moved out to the pad. Flight engineers made up for lost time today – and the massive rocket cleared the tower and thundered aloft.
Controllers had 58 minutes in the launch window in which to get the rocket and its precious cargo off the ground and into the darkening skies at Kourou. Both of the spacecraft on board the Ariane 5 are communications satellites. Their flight has seen several delays and was originally scheduled to take place in December of 2013.
In fall of last year, the Ariane 5 entered into the processing flow which sees the rocket readied for launch, its systems installed and components required to conduct the mission integrated.
The Ariane 5 was moved out to the Ensemble de Lancement Ariane – more commonly referred to as ELA-3. This is the pad from which the Ariane 5 is launched from. Once the Ariane 5 had arrived there, normal pre-launch procedures began in earnest. The rocket was then hooked up to the various communications and other necessary essentials to ensure that it was functioning properly before lifting off the pad.
Ariane 5 is a large vehicle – standing in at more than 150 feet tall, the booster has a cryogenic core stage, powered by a Vulcain rocket as well as two Étages d’Accélération à Poudre, or “EAPS.” These are solid rocket motors which provide the extra “push” needed to lift the launch vehicle and its payload free of Earth’s gravity well.
This is not the first slip of the launch however. The flight of these two telecommunications satellites had originally been planned to take place in December of last year. The launch vehicle processing “flow” began for the 151 foot tall rocket in fall of last year. The Ariane 5’s cryogenic main “core” stage, avionics and two solid rocket motors were integrated and the rocket was ready to ferry its precious cargo to orbit.
At the very opening of the launch window – the word was given and the Vulcain engine thundered into angry life. After about eight seconds all systems were shown to be running in the “green.” At this point, the rocket’s flight computer saw that all systems were, in terms of aerospace parlance “nominal.”
At this point the two EAPS were activated, each adding 1.5 million pounds of thrust to the equation, an estimated 92 percent of the thrust required to successfully carry out the mission – and the Ariane 5 was on its way.
Four-and-a-half seconds into the flight and the Ariane 5 initiated its yaw-pitch program, placing it on the correct azimuth to deliver the two satellites to their required orbits. A minute in and the Ariane 5 was flying through the area of maximum dynamic pressure or “max q.” At this point, the rocket’s speed when combined with the Earth’s atmospheric pressure places the greatest amount of stress on the launch vehicle on its path “uphill.” At this point the Ariane 5 was traveling supersonic – faster than the speed of sound.
At almost three minutes in, the two EAPS were almost spent and were jettisoned – left to fall back down to the Atlantic Ocean. The two solid rocket motors are not recovered. They fell some 300 miles away from the Kourou launch site. Approximately a half hour later and the Ariane 5 had ferried the two satellites out of most of Earth’s atmosphere. Its mission complete, the payload fairing separates and also fell back to Earth.
Nine minutes into the flight, the Vulcain shut down and stage separation took place. The Ariane 5’s second stage, powered by a Aestus rocket engine took up the task of placing the pair of satellites in their proper orbits. The Aestus is capable of being restarted, it is capable of providing an estimated 6,100 lbs of thrust.
An estimated 24 minutes into the mission and the two spacecraft were traveling of some 5,700 miles per hour and some 100 miles in altitude – Geostationary Transfer Orbit (GTO).
The first satellite out of the SYLDA payload carrier was Astra 5B – just shy of 30 minutes into the flight and the spacecraft was placed into an orbit which will see it approach as near the Earth (perigee) as some 155 miles and as far out (apogee) as 22,000 miles.
Amazonas 4A was deployed about 17 minutes later. All total, from lift off to final deployment less than an hour had elapsed – just some 57 minutes. It marks the half-way point for Paris, France Arianespace which has two more Ariane 5 launches scheduled on the 2014 flight manifest.
The Ariane 5 is a two-stage rocket which conducted its first flight back in June of 1996. As with so many new launch vehicles – it was not a successful launch with the rocket self-destructing less than a minute into the flight. The Ariane V is of a similar class to the U.S. Delta IV Medium, Atlas V and Falcon 9 family of launch vehicles.
Astrium, an EADS company, is the prime contractor on the Ariane 5 which has been used to launch deep space missions such as Rosetta as well as all of four the European Space Agency’s (ESA) Automated Transfer Vehicles (ATV) which have currently flown to the International Space Station. The Ariane 5 is described by Arianespace as being capable of lifting payloads weighing more than 10 metric tons to geostationary transfer orbit (GTO) and over 20 metric tons into low-Earth orbit (LEO).
The first stage’s Vulcain is fueled by a mixture of liquid oxygen (LOX) and liquid hydrogen. The cryogenic main stage is comprised of a 100 foot tall (30 meter) tank which has two compartments, the first carries the 130 tons of LOX, the other the 25 tons of liquid hydrogen. Even when dry (empty) this part of the first stage weighs in at a hefty 15 tons.
Astra 5B was built by Airbus Defence and Space for SES. It will orbit at 31.5 degrees east. It is based off the Eurostar E3000 platform. As it is designed for telecommunications purposes, it is equipped with some 40 Ku-band and 6 Ka-band transponders. Astra 5B will be the 56th satellite in SES’ fleet.
Amazonas 4A, which will occupy the lower rack on the SYLDA, was built by Dulles, Virginia-based Orbital Sciences Corporation. Amazonas 4A has two deployable solar arrays and 24 Ku-band transponders. It will be controlled by HISPASAT and will orbit at 61 degrees west.
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.