January 1982:space activities report

GALILEO... WORK CONTINUES

Components for the Galileo spacecraft, scheduled for a 1985 launch to Jupiter, are nearing completion, and the development model for the heat shield on the probe recently passed tests at the NASA Ames Research Center. Galileo is a two spacecraft (orbiter and entry probe) mission to extend our knowledge about Jupiter and its moons.

The probe heat shield is only one of hundreds of components which are either now undergoing tests or will soon begin their test phase. Programme manager Ron McCullar says that approximately 95 percent of the flight parts have been delivered and the designs for the two spacecraft and the mission are nearing completion.

The Ames-designed probe heat shield, being built by General Electric, will encase the Jupiter probe instruments with two pieces. The first, a conical-shaped front shield made from a carbon cloth treated in plastic resin (carbon phenolic), will be 10cm thick at the nose and up to 125 cm in diameter. The rear piece will be composed of a slightly different material, nylon phenolic, because this lower density material will save weight while still providing adequate protection for the less severe afterbody heating environment.

The probe, when it plunges into Jupiter’s atmosphere, will be travelling at 48.2km/s (115,000 mph), fast enough to cross the Atlantic in under two minutes. This entry speed will expose the probe to nearly seven times as much radiation as our Sun produces at its surface.

Upon entry, aerodynamic braking by Jupiter’s thick atmosphere will decelerate the probe at 300g. During this extreme braking, the sacrificial front body shield will vaporise down to a mere 1 cm. The vaporisation of the carbon phenolic material will provide a heat-absorbing blanket to protect the seven probe instruments until a parachute opens and yanks the remaining shields away. The probe then has about an hour to make measurements of Jupiter’s atmosphere.

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SPACE AT PARIS '81

The 1981 Paris Air Show featured few new items of space hardware, in contrast with previous years when the Soviets at least revealed new items of their spaceflight inventory, writes Neville Kidger. However, in the year of the 20th anniversary of Gagarin’s flight, the Soviets chose to show the difference in the spacecraft of that era with the orbital stations of today.

The Soviet pavilion featured full-scale replicas of the Vostok 1 spacecraft, in which Gagarin made a flight of 108 minutes,and the Salyut 6/Soyuz/Progress space complex, in which 27 cosmonauts worked and two stayed for periods up to 185 days. Also on view were descent modules of both Vostok and Soyuz,which looked real — even down to the shredded insulating material on the Soyuz exterior. It was possible to go inside the Salyut space station and look at the shower, food, beds and other items which support the life of cosmonauts in orbit. Cosmonaut Valeri Ryumin made a brief, unannounced, appearance.

Other Soviet hardware displayed included a full-scale mockup of the Gorizont communications satellite, through which some of the TV of the 1980 Olympiad was broadcast, a Salyut EVA space suit, Progress cargo module, FCC control panel from Kaliningrad and several models of the scientific equipment used by Salyut 6 cosmonauts, including biological and technological installations and torqueless tools. A film of the Soyuz 22 mission was continuously shown in the cinema.

The NASA pavilion did not dwell on history but showed future projects, with models of the Galileo Jupiter Orbiter probe and Landsat D spacecraft hanging above visitors’ heads. The largest display in the NASA pavilion was a mock-up of the Shuttle orbiter flight deck, with two dummies at work inside it. Above that was an astronaut in full Shuttle EVA regalia flying, as if in space, with the aid of a manoeuvring unit. A video show accompanied the display with actual space footage from the STS-1 flight. Other audio-visual displays illustrated other areas of NASA’s space and aeronautical activities.

In the French Space Agency’s hall was a full-size mock-up of the SPOT Earth observation satellite in its Ariane payload shroud. This provided a marked contrast to the payload shroud of the French-developed Diamant launcher which lay beside it. The three-story exhibition featured many satellite models,including Symphonie, Peole, OAO and the Shuttle. The upcoming flight of a Frenchman to a Soviet Salyut space station was illustrated by a small model of the Salyut 6 space station, autographed by the cosmonaut trainees themselves. Photographs of the two men in Star City, near Moscow, were around the model. Arianespace,the company formed to market the launcher,featured actual production hardware of the ESA launcher and models of future development versions, planned for the mid-1980’s. A slide show, with as many as eight separate simultaneous images, illustrated the manufacture and launching of the rocket.

The highlight of the ESA pavilion, apart from the warm hospitality of the staff, was a mock-up of Spacelab with two dummies inside who described the functions and purpose of the laboratory. Live TV from London via OTS-2 was featured on one wall while models of Meteosat and Sirio 2 were also shown.

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SOLAR OPTICAL TELESCOPE

NASA’s Office of Space Science has selected two scientific investigators to develop instruments to fly aboard the planned Solar Optical Telescope, first due for launch aboard the Shuttle in 1987.

Dr. Harold Zirin proposes developing a photometric filtergraph which will be able to observe the Sun through various optical filters in the near infrared, visible and ultraviolet regions of the spectrum. The proposed instrument will be able to take several hundreds of images on film during the one-week mission of the Solar Optical Telescope.

Dr. Alan Tuttle’s proposal is for a coordinated filtergraph and spectrograph which will include a tunable visible-light and optical filter system and a high resolution spectrograph with motion compensation. The spectrograph will operate in both the visible and ultraviolet spectral regions. Both the filtergraph and the spectrograph will record data using charge-coupled device imaging systems, and relay the information directly to the ground for examination by scientists.

These two instrument assemblies will be located at the focal point of a 1.25 m diameter telescope mounted on a pointing system located within the Shuttle payload bay. The Solar Optical Telescope will be designed for a variety of solar physics investigations on several Spacelab flights.

The current timetable for the first flight of this instrument,which is expected to expand considerably on the so-far unsurpassed results of the Skylab Apollo Telescope Mount, shows initial launch in the spring of 1987 with reflights scheduled thereafter.