Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, April 25, 1990 TAG: 9004250402
SECTION: NATIONAL/INTERNATIONAL PAGE: A1 EDITION: STATE
SOURCE: Associated Press
DATELINE: CAPE CANAVERAL, FLA. LENGTH: Long
Less than five hours after it rode into space aboard the shuttle Discovery on Tuesday, the $1.5 billion telescope sent its first test radio signal. At the sign of life, applause and cheers erupted at the Goddard Space Flight Center in Maryland where astronomers monitored their spacecraft.
Later this week, a command radioed from Earth will open the lens cap on the telescope and allow the first light from space to strike its mirror.
If telescopes have a most-important moment, that will be it. It will mean that Hubble, flying free 380 miles above the world, has opened its eyes to the heavens and is ready to make discoveries not yet imagined.
NASA is so concerned about that lens cap opening, it is keeping the shuttle Discovery in the neighborhood just in case. Astronauts Bruce McCandless and Kathryn Sullivan will be suited up, ready to walk in space to open the cap - formally called an aperture door - by hand.
Opening that door is step 65 in a sequence NASA laid out to activate and check out the $1.5 billion telescope and its five instruments before the shuttle pulls away and leaves the Hubble to its own devices.
The telescope was supposed to be launched in 1983, but technical problems and the Challenger accident delayed its deployment. It suffered a further delay two weeks ago when the countdown was stopped at the four-minutes-to-go point because of a faulty hydraulic unit on the shuttle.
While it remained on Earth, the telescope cost $7 million a month to exercise and keep in readiness.
The instruments themselves, mounted behind the telescope's 94.5 inch mirror, were warmed up Tuesday, soon after the shuttle lifted into a sunny Florida sky. Their ability to communicate with the ground was checked one-by-one.
One of the instruments, the Wide-Field and Planetary Camera, operates in two modes as its name implies. In the wide-field mode, the camera can photograph a giant galaxy 60 million light years from Earth. How far is that? Light travels 5,900,000,000,000 miles in one year.
With this instrument, astronomers plan to look into crowded centers of galaxies and search for disk-shaped formations of gas and dust around young stars where new planetary systems may be forming. If they discover a star like our sun and planets like our Earth, they may be on the trail of other life in the universe.
In its planetary mode, the camera can photograph entire hemispheres of any planet in our solar system in a single exposure. Scientists will be able to take photographs of Neptune as sharp and detailed as those taken by the two Voyager spacecraft when each was only five days away.
A second instrument is the Faint-Object Camera, provided by the European Space Agency. It is designed to detect distant objects and extends the reach of the telescope to the greatest possible distance.
This camera will photograph stars seven times farther away than any before it. "Many stars and galaxies that are considered faint by present standards will be almost blazing light sources to the Faint-Object Camera," says a NASA brochure.
A third instrument, the Faint-Object Spectrograph, will analyze the light from individual stars and nebulae in our galaxy and those nearby and provide data to deduce their physical and chemical properties. It will investigate more distant galaxies and study light from quasars and whole galaxies.
The spectrograph also will be used to study erupting stars - supernova - and determine the rate at which the expansion of the universe has been slowing over billions of years.
Its conclusions will help settle a scientific argument over nothing less than the likely fate of the universe: If the deceleration rate is small, then the universe will continue to expand forever, scientists believe. If it is as fast as some scientists maintain, then the expansion will come to a halt eventually and the universe will begin to contract, they say.
A fourth instrument, the Goddard High Resolution Spectrograph, sees only ultraviolet light to examine physical and chemical conditions in objects it looks at. It will be able to observe trace substances in interstellar space that can't be detected any other way. When the telescope is tracking a bright comet, the spectrograph will search for evidence that comets were formed from interstellar matter. And it will measure temperatures of explosion in the upper atmospheres of red dwarf stars.
The simplest instrument on the Hubble, containing no moving parts, is the High-Speed Photometer, a light meter that measures the intensity, wavelength and other properties of light. It will measure the structure and ongoing physical processes in interacting binary stars - including those that may contain black holes.
With this instrument, astronomers will study many of the exotic phenomena in the ring systems of Saturn, Jupiter and Uranus and also will determine the diameters of stars.
There is, effectively, a sixth instrument on the Hubble; fine guidance sensors that point the telescope with precision. From Washington, claim scientists, the sensors could spot a dime in the window of the World Trade Center in Manhattan - and hold it steady in sight for 24 hours.
A University of Virginia astronomer who has spent more than a quarter of a century helping NASA design the Hubble Space Telescope is waiting to be surprised.
"You can't think of all the possible things it can do and discover," said Laurence Frederick, who began working on the project in 1963. "Otherwise there would be no point in building it."
Frederick, 63, a professor of astronomy, has been working on the Hubbble project since 1963. "There's a real feeling of anticipation, but one sort of tempers this," Frederick said. "I hope people don't expect a miracle right away, but something close to a miracle is going to come."
by CNB