June 1983:European space status report

Ariane

It would be too much of a play on words to suggest
that Ariane has had its "ups" and “downs." The early
days of a launcher will always be difficult, and failures
highlighted, but there is full confidence in the long term
future of Ariane.
ESA remains responsible for the R&D element of the
future European Launcher Programme in the sense that
the ESA Council decided to undertake a follow-on
programme to produce two upgraded versions: Ariane 2 and Ariane 3. The two are of similar design, but Ariane 3 will be fitted with additional boosters. This
will give Ariane 2 the capability to place a payload in
excess of 2,000 kg into geosynchronous transfer orbit,
and Ariane 3 will take more than 2,400 kg - or two
payloads of 1,140 kg - in a dual launch. Once the
launchers have been proved in flight tests, the responsibility for production models passes to Arianespace
and becomes essentially a commercial operation.

Deciding on future generations of launchers requires
a crystal ball, in the sense that one needs to assess
the requirements of satellite builders and users in the
late 1980's and early 1990's. The expectation of the
size and scope of geostationary satellites has led ESA
to tailor Ariane 4 to allow Europe to offer a highly
competitive launch system throughout the 1986-92
period.
Ariane 4 will be a versatile launch system capable
of putting any payload weighing between 2 and 4.3
tonnes into transfer orbit, by using various combinations of liquid or solid propellant boosters. A demonstration firing is planned for the end of 1985 or early
1986. The cost of placing a kilogramme of payload in
orbit is expected to be only 40% of that of Ariane 1.
Another milestone in the long term could result from
studies of an even higher performance launcher, which
would be available from 1990 onwards; this new version should ensure a further cost reduction. To enhance the operational flexibility of the launch facilities and provide redundancy for the present Ariane launch site (ELA-1), it has been decided to construct
a second Ariane launch site (ELA-2) in Kourou. By
1985, this will reduce to one month the necessary
interval between successive launches of the various
uprated versions of Ariane.

Manned European Flight

The arguments for and against European participation in manned flight waxed strong before the decision
was made to build Spacelab, and have continued during
the development stage. One suspects that they will
still be voiced after the first flights this year. The initial
success of the Shuttle, and the less publicly acclaimed
success of the first Spacelab element - the pallet - to
fly, is heartening.

In operation, Spacelab - both the pressurised module
and the pallet - will be transported to and from orbit
in the cargo bay of the Shuttle Orbiter, and will remain
there throughout the flight. Spacelab therefore extends
the Shuttle's capability, and the Orbiter/Spacelab combination constitutes a space station which can remain
in orbit for about seven days. This "space station" will
provide opportunities for experimenters to live and
work in space under conditions that are little more
exacting than those experienced on Earth. Furthermore,
Spacelab can be reconfigured after each flight to satisfy
the needs of the next mission. Considerable flexibility
in configuration and mission structuring is available to
the user.

Only after two or three flights will we have assessed
the full implications of Spacelab and its potential uses,
especially the extent to which it can be used for the
manufacture of prototype commercial products impossible to produce on Earth. These include alloys and
composite materials with new properties, crystals of
improved characteristics for the electronic components
industry, high quality glasses for the optical industry,
improved vaccines and biological products.

Apart from improving the existing model to increase
time in orbit, experiment capacity and power, Europe
is looking ahead to an era when the Shuttle will be
used as a means of taking free-flying payloads into
space, and retrieving them later. With this in mind,
studies are well advanced into various configurations
for Eureca: the European Retrievable Carrier. The cry
of "Eureka" is attributed to Archimedes when he found
a means of determining the purity of gold. Naturally
we hope Europe will find gold in its advanced ideas for
such space platforms.

Other Projects

I have already mentioned our past successes in the
scientific field. Briefly, ESA has five scientific projects
in various stages of development:

Exosat will determine the positions and examine the
structures of celestial X-ray sources. It will use lunar
occupation as well as other observation methods. The
satellite is ready and awaits a suitable launch window.

Space Telescope: this 2.4 m telescope will dominate astronomical research for the rest of the century,
contributing appreciably to our understanding of the Universe. Europe is providing about
15% of the total cost: the Faint-Object Camera, its
associated detector and the solar array. In return we
will have 15% of the observing time of the telescope
which is due to operate for at least 10 years.

The International Solar-Polar Mission (ISPM) has
been dogged by ill-fortune. The original idea to send
two satellites out of the ecliptic plane with the help of
Jupiter's gravitational field to fly over the Sun's north
and south poles had to be abandoned when the NASA
spacecraft was a victim of the budgetary cuts. ESA
kept faith with the scientific community but the indecision over the development of an interim upper stage,
by means of which the satellite will be launched into
an Earth-Jupiter transfer orbit from the Shuttle, has
delayed the launch still further.

Giotto has captured the imagination of the world;
laymen and scientists alike can appreciate that a
”once-only" mission of this nature needs very precise
planning and not a little good fortune to succeed. The
satellite will be launched in July 1985, and should
encounter Halley's Comet in March 1986, one month
after perihelion when the comet is at its most active.

Finally, Hipparcos will measure the five main astrometric parameters of distance, position and proper
motions of about 100,000 selected stars.

Communications

The advantages of a European Agency being able to
do business with other international organisations was
well illustrated when INMARSAT undertook to use
Marecs satellites in its worldwide system.
The use of satellites for maritime telecommunications
was expected to demonstrate a number of advantages
over the HF/MF radio frequency bands already in use.
In particular, telephone and telex connections would
be possible on a direct-dial basis to the subscriber,
with the high transmission quality associated with
international connections. Such services were not available at anything approaching this quality at HF/MF
frequencies, and congestion and the operating proce¬
dures imposed by working under difficult conditions
were leading to considerable transmission delays. Waiting times with the new system will be reduced from
several hours to a question of minutes, if not seconds.

The Marecs satellites, with a capacity of some 40
channels, permit operations with ship terminals with
dish antennae of approximately 1 m diameter. Aside
from the pure communications capability (fully maintainable during eclipse), a search-and-rescue feature on
the satellite can relay messages to shore from vessels
in distress using low-power buoys.

Meanwhile we await the launch of ECS-1 by Ariane,
the first element in an operational European regional
telecommunications system. The ECS series is ESA's
second generation of point-to-point communications
satellites. The repeaters of these satellites will be able
to relay either telephony or television signals.
The ECS satellite, which is a development of OTS,
is of the one-tonne class and will have a seven-year
lifetime. It will provide services over an area similar to
that of OTS, but with a combination of Eurobeam and
multiple Spotbeam coverage. The greater prime power
requirement compared with OTS leads to the use of a
larger solar array. The satellite will have a capacity
equivalent to 15,000 telephone channels as well as
two TV channels and will, like OTS, operate in the
11/14 GHz frequency bands. It will operate with a
network of perhaps 20 ground stations, each with an
antenna of between 14 and 18 m diameter.

From ECS-2 "multiservices" will be included. These
can be defined as all the non-PTT services, and for
ECS-2 are geared to the growing demand for high¬
speed, heavy bulk data transmission and programme
transfer. Multinational business concerns are interested
in such services for file transfers, high-speed facsimile
and video service, including video-teleconference
facilities.
The major customers for telecommunications satellites in Europe, the PTTs created Interim EUTELSAT to
act as their "single customer voice", and also to
manage the European satellite telecommunications services, being responsible for their exploitation, and for
relations with users. Under the terms of a contract
concluded between ESA and EUTELSAT, ESA will
provide two satellites in orbit for a period of ten years.