“Ariane 10 tonnes”: new lift capability for Europe

To meet the needs of the market, Europe is about to launch
(target launch date 28 November) an improved version of
Ariane 5 that will be capable of placing up to 10 tonnes
of payload in geostationary transfer orbit. This new
development is the key to maintaining Europe’s
competitiveness in the commercial space transport sector
and securing its independent access to space for the
foreseeable future.

Like the 1979 Ariane 1, forerunner of Ariane 2, 3 and 4,
Ariane 5 was conceived from the outset as the first in a
new family of launchers that would maintain Europe with
a sure and competitive means of access to space. So, in
October 1995, even before the new launcher’s first
flight, the ESA Member States decided at a Council
meeting at ministerial level in Toulouse, to start work
on an improved version of Ariane 5 with increased lift
capability.

Commercial space transport, which represents most of the
Ariane launchers’ activity, depends to a large extent
on developments in the satellite market. During the
1990s, that market saw a sharp increase in the power
and capacity (thus also mass) of geostationary
telecommunications satellites, which alone account for
more than 95% of the commercial launch market. In the
course of 10 years, large satellites increased in mass
from 2.5 to almost 5 tonnes. Since 2000, orders have
also been placed for satellites weighing 6 tonnes or
more.

At the same time, the competitive environment has
changed. Orders for new satellites have slowed down,
the communications sector is going through a phase of
consolidation and rationalisation, and many launchers
are now operating in competition with the Ariane system,
resulting in overcapacity.

A response to new market needs

In order to provide competitive launch capabilities, the
Ariane system has been geared since the beginning of the
1980s to dual launches of geostationary satellites. The
new market conditions have made this even more imperative.
In 1995, ESA commissioned studies and predevelopment work
to increase Ariane 5’s lift capability even further and
in May 1999, the ESA Council meeting at ministerial level
approved a new plan to improve the Ariane 5 launcher so
as to achieve the aim of placing 10 tonnes in geostationary
transfer orbit in 2002 and 12 tonnes by 2006. ESA has
delegated the technical management of these Ariane 5
follow-on development programmes, like earlier ones in the
series, to the French space agency, CNES, and Arianespace
will continue to be responsible for the marketing side.

This new lift capability, and the strategy for achieving
it while at the same time reducing the launcher production
costs, means that Ariane 5 will be able to launch almost
all the satellites on the market, from the largest to the
smallest, in pairs. Also, its fairing, 5.4 m in diameter,
will accommodate the most bulky satellites.

This release from pairing constraints is accompanied
by greater flexibility in the requirements regarding
occupancy. The launcher has been designed so as to
achieve a very substantial reduction in the cost per
kg in orbit, with the result that it will still be
competitive even if it carries two satellites that
together weigh less than 10 tonnes.

In practice, as a result of these improvements, Ariane 5
will have a powerful and at the same time standardised
configuration enabling it to take satellites on board in
pairs as they arrive in Kourou.

All these features represent prime assets that will
secure the lasting success of Arianespace’s commercial
range in years to come.

Tried and tested architecture

The first Ariane 5 launcher with a lift capability of 10
tonnes will be used on Flight 157, the 14th Ariane 5
launch and the European launcher’s 11th commercial
mission since it was commissioned by Arianespace in 1999.
On 28 November, the launcher lifting off from Kourou
in French Guiana, will orbit two satellites, the Hot
Bird(TM) 7 communication satellite for Eutelsat, and the
STENTOR space telecom technology satellite for the French
Space Agency, CNES.

The “Ariane 10 tonnes” launcher or Ariane 5 ECA, to give
it its official name, has the same general architecture
as the Ariane 5 launcher, with two solid boosters (EAP)
to lift it off the launch pad, a cryogenic main stage
(EPC) to do most of the work of getting into orbit, and
an upper stage to place the satellites in the target
orbit, in most cases a geostationary transfer orbit of
up to 36,000 km from which their on-board propulsion
system will be able to help them into their final orbit.

To raise the lift capability from 5.9 tonnes to 10
tonnes for a dual launch, most of these features have
been “beefed-up” to increase their performance.

“Beefed-up” engines

The solid booster engines — made by Europropulsion
(Italy, France) — each comprise three segments and the
smallest of these now carries 10%, or approximately 2.5
tonnes, more propellant. Because of its form, this
segment is the one, which burns most quickly and gives
the launcher its initial thrust. The extra load it now
carries in fact provides an additional 50 tonnes of
thrust in the first 20 seconds following lift-off.
So, between them, the solid boosters deliver a thrust
of 1 400 tonnes, or 10 times that delivered by the
engine of the central stage. At the end of the day,
that means 400 kg more payload. Also, these boosters
are equipped with a new nozzle, which has fewer parts
and so is easier and cheaper to produce.

The cryogenic Vulcain engine of the main stage, produced
by Snecma (France), has also been modified to increase
its thrust by 20%, to 137 tonnes. The new version,
Vulcain 2, burns a mixture of propellants enriched with
20% liquid oxygen under slightly higher pressure than
the previous version. As a result of this change in the
mixture of propellants, FiatAvio (Italy) has had to
develop a new oxygen turbopump, capable of rotating at
13,000 rpm and delivering a pressure of 161 bars. It
has also been necessary to increase the capacity of the
liquid oxygen tank in this stage by 15 tonnes. This has
been achieved, without altering the structure of the
stage, simply by moving the common base of the liquid
oxygen and hydrogen tanks 640mm.

Another improvement in Vulcain 2 is a new nozzle
divergent, manufactured by Volvo Aero (Sweden), which
enables the emissions from the turbopumps to be
reinjected into the main system and improves the
engine’s performance at high altitudes.

All in all, the Vulcain 2 alone provides an additional
lift capability of 1,300 kg to destinations in
geostationary transfer orbit.

The legacy of Ariane 4

The most important new feature of “Ariane 10 tonnes” is
the upper stage. The storable propellant stage (EPS) has
been replaced by a cryogenic upper stage (ESC-A) carrying
14.6 tonnes of liquid oxygen and hydrogen. Produced in
Bremen under the prime contractorship of Astrium
(Germany), it makes extensive use of tried and tested
technologies, including the liquid oxygen tank, thrust
frame and propulsion assembly used in the third stage
of Ariane 4, together with its HM-7B engine, supplied
by Snecma. The liquid hydrogen tank employs the
technologies developed for the tank housed in the main
stage. The only new feature is the dome-shaped bulkhead,
which holds the liquid oxygen tank.

The stage rests on a composite cylindrical section
5.4 m in diameter and 2.8 m high, produced by EADS
CASA Espacio (Spain).

The ESC-A is the crowning achievement among the
improvements to Ariane 5. It alone accounts for 60% of
the increase in performance compared with the preceding
launcher in the series, with almost no change in the
production cost. It is also responsible for deploying
the satellites with maximum precision so as to ensure
that they have an optimum operational life.

A rigorous qualification programme

All these modifications to the Ariane 5 launcher have
been subjected to rigorous qualification procedures
within the framework of the ESA development programmes
and the Ariane Research and Technology Accompaniment
programme, ARTA, which is also managed by ESA and funded
by the European governments.

The increased propellant charge carried by the boosters
and their new nozzle were qualified in two full-scale
hot tests conducted at Kourou in May 2000 and November
2001. And the Vulcain 2 engine has undergone more than
130 test-stand firings at Vernon, in Normandy, and
Lampoldshausen, in Baden-Würtemberg, accumulating more
than 50,000 seconds of operating time, equivalent to
about 100 flights.

The ESC-A stage has been subjected to standard
qualification with dynamic and vibration tests
conducted at the IABG Centre at Ottobrunn (Germany).
The HM-7B engine, although it has already flown more
than 130 missions, has undergone its own validation
test campaign to ensure that it functions satisfactorily
in Ariane 5 flight conditions and, in particular, with
200 seconds more burn time. An operational test campaign
has also been conducted at Kourou on a complete stage,
to check the procedures and interfaces required for
filling and activating the stage on the launch site,
including the use of new retractable cryogenic arms
mounted on the mobile launch table mast.

Objective: Re-ignition

The “Ariane 10 tonnes” will be the standard version of
the Ariane 5 launcher for the next few years. However,
its successor is already being planned within the
framework of the Ariane 5 Plus programme adopted at
the ESA Council meetings at ministerial level held in
Brussels in 1999 and Edinburgh in 2001. Ariane 5’s
development potential is by no means exhausted and this
new version could increase its lift capability to the
point of placing 12 tonnes in geostationary transfer
orbit.

A new and more powerful upper stage is being studied. It
will be equipped with a new engine, the Vinci, already
under development, capable of delivering three times as
much thrust and performing re-ignition and ballistic
phases. The re-ignition facility will give Ariane 5
added flexibility to meet the new market demand to place
satellites in other orbits or to carry out complex tasks
such as placing constellation clusters like Galileo in
medium Earth orbit.

For further information, please contact:

ESA Media Relations Service

Tel: +33(0)1.53.69.7155

Fax: +33(0)1.53.69.7690