Ariane 6
Planning for Europe’s Next Generation Launcher
by Ed Kyle 03/12/2013
P7C Concept for Ariane 6
During November, 2012, a European Space Agency Council approved funding both for Ariane 5 ME (Midlife Extension) development and for detailed definition studies of a new launcher named Ariane 6. Plans called for Ariane 6 to use as many elements as possible from Ariane 5 ME. Both efforts were funded for two years. A final decision on the continuation of both launchers would be made in 2014.
Ariane 5 ME improves existing Ariane 5 ECA performance by using an improved second stage that will be powered by the restartable Vinci liquid hydrogen/oxygen engine. The upgraded rocket will lift up to 12 tonnes to GTO, with a maiden flight expected to occur in 2017 or 2018. The Ariane 5 ME approval was a win for Germany’s Ariane 5 prime contractor Astrium. The development effort is expected to cost 1.4 billion ($1.8 billion).
Like its Ariane predecessors, Ariane 5 ME is designed to carry two satellites on each GTO mission. Ariancespace has found it more and more difficult to match payloads for such missions. Ariane 6, as a result, was conceived by French space agency CNES as a rocket optimized to launch one satellite at a time for the least amount of money.
A critical factor in the design was the likely range of future communication satellite weights, which initial studies determined could range from 2 to 8 tonnes with most payloads in the 3 to 6.5 tonne range.
Also read: Ariane 5 Data Sheet
P1B Concept for Ariane 6
CNES studied a variety of Ariane 6 alternatives, including some early concepts that used the Ariane 5 core but with smaller, less expensive monolithic solid boosters, but studies eventually settled on three potential options. All three options would use the 4.4 meter diameter Vinci powered upper stage from Ariane 5 ME and a 5.2 meter diameter payload fairing. Variantions involved the lower stage combinations. Two options used solid motors while a third used a liquid first stage with solid strap-on boosters.
The liquid alternative, dubbed H2C, would use zero to six solid P33 (“P” for solid, “33” for the propellant tonnes) strap-on boosters to augment an H165 core stage (“H” means hydrogen and “165” refers to the tonnes of propellant carried) powered by two 150 tonne thrust engines derived from Ariane 5’s existing Vulcain 2 main engine. The Vinci powered second stage would weigh 31 tonnes. H2C would lift up to 8.4 tonnes to GTO with six boosters, or 2.2, 5.6, and 6.7 tonnes for zero, two, or four boosters respectfully.
The first solid motor option, named P1B, would use two 3.7 meter diameter solid motor stages, augmented by strap on solid motors, topped by the Vinci upper stage. All of the solid motors would be monolithic (no motor segments) to cut costs and would use composite cases to improve propellant mass ratios. The P180 first stage (180 tonnes of propellant) would be topped by a P110 second stage.
A varying number of P39 strap on boosters would provide a range of payload capabilities. The boosters would likely consist of sets of ground and air ignited motors. The ground-lit boosters would be jettisonned upon burnout. P1B would be able to lift 8.1 tonnes to GTO with six boosters, or 2.1, 5.0, and 6.5 tonnes for zero, two, or four boosters respectfully.
Ariane 5 ME and Ariane 6 P7C Comparison
A second solid motor alternative was P7C. Rather than the three varying types of solid motors used by P1B, P7C would use combinations of only one type of solid motor. One 3.7 meter diameter P135 motor would serve as the rocket’s second stage. Two or three P135 motors would be combined to work as a first stage, with all of the motors firing and separating together. Although promising lower costs, P7C was also more limited since its two variants could carry a maximum of either 3.4 tonnes or 6.5 tonnes to GTO.
One advantage of the P7C is that its “smaller” P135 motors (which would still be the world’s largest monolithic solid motors) might offer a path to upgrade Vega, Europe’s small all-solid launch vehicle. Vega’s current first stage is a P80 monolithic, which is currently the world’s largest non-segmented solid motor.
CNES favored the solid motor designs, which its studies showed offered better cost competitiveness than the cryogenic core design. The improved Vulcain 2 engine development effort would have been costly, as would have been use of two of the engines on each flight.
At the end of January, 2013, Astrium announced that it had won an Ariane 6 design contract. The company would perform initial definition and feasibility studies for the future Ariane 6, aiming to pin down the launcher’s primary specifications. Astrium would study the “PPH” (solid-solid-liquid hydrogen) design alternatives capable of lifting 3 to 6.5 tonnes to GTO. An important design goal was a per-launch price of €70 million Euros.
