Title: A space ticket for Europe
Pages: 50 - 53
Author: Ted Wilding White
A SPACE TICKET FOR EUROPE
BRITAIN HAS A SMALL SHARE IN THE WINNING CONSORTIUM FOR EUROPE'S FIRST MANNED SPACE VEHICLE. REPORT BY TED WILDING WHITE
Once upon a time there was a post-Apollo programme which promised a giant space station for the 1980's floating permanently around the Earth, serviced regularly by a fully reusable spaceplane. To placate the US Treasury, Europe was invited by NASA to participate in the creation. But the price was still too high. So the orbital station has died and the shuttle has become simply a semi-reusable orbital workhorse (DESIGN 303/58). The space station lives on as Spacelab, a much condensed poor relation of the original idea. In fact this orbiting laboratory will never leave the space shuttle in which it will be shot on 7-30 day missions and returned to Earth.
After much contention, Europe agreed that such a package at least fitted its purse, if not its greater aspirations. Full-scale development of Spacelab began this summer within a consortium of 19 companies from nine European nations (DESIGN 308/23).
The Spacelab consortium, led jointly by Erno Raumfahrttechnik of Germany and the German Dutch company VFW-Fokker, was picked out of two such consortia which each submitted competitive designs to the European Space Research Organisation earlier this year. The group is dominated by German industry because Germany is the major contributor to the project. ESRO's two other 'special projects' - the Ariane launch vehicle and an experimental maritime communications satellite - are French- and UK-dominated respectively. But Britain has a modest share in Spacelab with Hawker Siddeley Dynamics obtaining £5m worth of the £95m overall contract.
At least, Spacelab holds European experiment packages and European scientists to operate them. It also represents Europe's first venture into the field of manned spaceflight although the important distinguishing feature, the life support equipment (air supply and temperature control), is to be bought from the United States.
Not designed to leave the womb of its space shuttle mother craft, Spacelab is effectively little more than a passive unit and user of electricity. The technical risk is minimal but, on the other hand, so is its contribution to European technology - a point that formed the core of opposition to the undertaking. But it was the only element of the whole shuttle programme that Europe could afford and that NASA would allow.
Whether or not it offers technological advancement, Spacelab is at least unique. It will provide the first opportunity for scientists themselves to get to grips with their own experiments in space. Scientists will need very little space training before making a flight and will be able to operate in a comfortable 'shirt-sleeve' environment.
Spacelab is ingenious; its key feature is flexibility. It will comprise two sections, a pressurised laboratory where up to four scientists can work and, attached to this, a platform or pallet carrying the larger instruments. Both laboratory and pallet have been designed in modular 'kit' form. So, when an establishment or government requires use of a Spacelab, an appropriate number of laboratory and pallet sections can be assembled and delivered by air or road to the user who then installs his own scientific equipment. At least, that is the theory. The loaded Spacelab with accompanymg scientists is then shipped to the launch site. After the mission, the equipment is removed and the Spacelab reassembled to the specifications of the next customer. The design lifetime of the unit is 50 missions.
The basic laboratory module comprises one cylindrical centre segment and two end pieces, between which a second identical centre segment can be inserted. The primary structure is basically the outer space-shell of these sections, constructed of waffle-pattern stressed panels. A secondary structure consists mainly of an assembly of equipment racks and floors which is simply slid in and out on rails like airfreight loading pallets. Removal of the secondary unit on the ground exposes all wiring and pipes and air and water for maintenance. This unit also includes all life-support controls, safety warnings, a computer and the permanent general controls. Except for power supply, the laboratory will be totally independent.
Access is by way of a tunnel, also modular and extendible, between the aft bulkhead of the shuttle cabin and the forward endpiece of the laboratory. Until recently, both proposed designs showed a larger lab section linked directly to the shuttle cabin bulkhead. Then the shuttle contractor declared new centre of gravity and weight limitations which forced the Spacelab bulk further aft. The lab module could no longer link directly without a longer and heavier Spacelab: hence the tunnel. In any case, weight had to be saved: hence a crew reduction from six to four.
On its own, such a unit would be adequate for a number of small internal experiments such as zero-gravity engineering. Small telescopes and sensors could be extended through airlocks, of which there is one in each section as well as one in the access tunnel. Each airlock exit hatch also has small windows of high-quality glass, equipped with camera mounts. But large telescopes and aerials are mounted on one or more identical trays or pallets suspended in the cargo bay behind the laboratory, linked only by control connections. There is room for three such pallets and the laboratory itself can be replaced by a further two pallets for a fully 'robot' payload.
It is these pallets for which Hawker Siddeley Dynamics has development responsibility. Each pallet has a shallow, U-shaped cross-section of waffle-pattern shell with mounting points for instruments weighing up to three tons. One great advantage over unmanned satellites is therefore obvious: no longer will there be the same need for highly expensive, ultra-lightweight instruments. Subsystems to support experiments can be housed in a small pressurised 'igloo' attached to the forward experiment pallet.
Spacelab certainly supports the adage that two intelligent approaches to the same highly specific problem usually produce similar solutions. Superficially, there is little to differentiate between this and the rejected proposal. The other consortium, led by MBB of Germany with members including BAC and GEC-Marconi of Britain, proposed a fixed-length tunnel so that lab size variations were more at the expense of the pallet length. But it also provided for central segments of three different sizes to give a wide range of discrete variations in lab size. Also, the pallets were linked rigidly together.
Actual production and ownership details for Spacelab are still unsettled. The contract only calls for delivery of one qualified flight unit plus two engineering units in 1979. Hawker's responsibility is to provide 15 pallet sections, or the equivalent of three pallet-only payload units (a minimum lab module is interchangeable with two pallet sections).
At present, NASA has agreed to buy only this first flight unit but has indicated that a second may be ordered soon. No one has any idea how many will be needed finally but official speculation puts it at five. That is as far as planning has apparently gone. The future, in fact, seems to rest on pure optimism rather than serious planning. European aspirations for
(Caption page 51) A full-size mock-up of the winning entry, showing the modular construction. The two U-shaped pallets at the back will carry the various instrument packages.
10, 20, even 30 missions per year are bandied about. But in practice, Europe still seems to be looking at the delivery of the first flight unit as an end in itself, not a beginning.
Spacelab payloads will not be cheap. They will almost certainly be too expensive for a single European establishment, or even a country. So bookings from this side of the Atlantic will probably all come from the European Space Agency, now slowly struggling into existence. If the precedent set by Europe's latest satellite, Cos-B is continued, then payloads centred on a single experiment or discipline supported by several countries will be preferable to fragmented projects. In terms of co-ordination and budgeting, the payloads will probably need as much advanced planning as the craft itself. If the current budget levels and one-per-year attitude continues, Europe will find its stake dwindling to the status of a modest ante. And at that level, it can profit only under the full control of the high players.
(Caption page 52) A mock-up was used to test out the design; the endpiece and tunnel through to the space shuttle cockpit is omitted.
Left, working space for up to four, with aids for efficient zero-gravity performance. Right, all equipment is stowed in modular racks so that faulty units can be replaced quickly between missions. The whole rack will also roll on and off the module floor.
(Caption page 53) Simple layout of the interior allows unimpeded access to the exit hatch and to the orbiter tunnel. Self-sufficient satellites can be released into space from the shuttle's 'cargo bay' as shown.
Left, the skin to surround the control module will be in a waffle pattern, though the exact material has not yet been selected. Right, the tunnel, control module and instrument pallets can be installed or removed from the space shuttle as a complete unit.