STAR SEARCH; HUBBLE'S SUCCESSORS TO HUNT PLANETS.
Spread out on the table before Charles Beichman at NASA's Jet Propulsion Laboratory is the kind of photo that can drive astronomers crazy.
It's an image, taken by the Hubble Space Telescope, of a disk of dust surrounding a nearby star. It probably - probably - shows rubble left over from the birth of a solar system like our own.
But astronomers can't see the planets.
To get any image at all, they had to block the star's blinding glare with a black circle that lets them see only the disk's outer fringe. And the mighty Hubble isn't nearly powerful enough to spot something as small as a planet anyway. The worlds astronomers so desperately seek stay hidden.
Beichman and others at JPL's Pasadena campus plan to change that.
Last week in an interview, they outlined their designs for a series of space-based telescopes that will peer inside other solar systems and spot light bouncing off distant worlds.
These new telescopes would replace the aging Hubble. If they work as expected, they will let scientists survey stars near Earth, count the planets surrounding them and determine which ones might support life.
``It's a noble goal,'' said Firouz Naderi, head of the telescope program at JPL. ``Just as the Egyptians were known for the pyramids, it's entirely possible that our civilization will be known as the one that discovered other planets and life.''
Search for life
The National Aeronautics and Space Administration project is just one part of a much larger new effort called Origins, which seeks answers to some of the most basic questions humanity can ask.
Launched in 1996 by NASA chief Dan Goldin, Origins is trying to trace the chain of creation, from the birth of the universe to the formation of galaxies and planets and living beings. It will bring together scientists from many disciplines and, NASA chiefs hope, respark Americans' interest in space exploration.
``It's something we think the public will be very engaged in, because these are very fundamental questions,'' said NASA spokesman Don Savage.
Those working on the program say the potential for discovery is enormous.
Swiss scientist Didier Queloz, part of the first team to discover a planet outside our solar system, is convinced that, sometime in the future, the hunt for Earthlike worlds will find life elsewhere in the universe.
``I am sure we'll find something,'' Queloz said. ``Maybe it's just trees, but there has to be something. We can't be unique.''
Nine planets found
Few scientific advances in recent years have created as much interest as the discovery of planets orbiting other stars. Depending on how you count, nine have been found so far.
The problem is, you can't actually see them. Astronomers spot them by detecting the wobble they create in the light from their parent stars. And because a planet has to be massive to cause that kind of wobble, all the planets detected so far have been giants like Jupiter or Saturn, not like Earth.
That is where the JPL telescopes come in. To find worlds potentially friendlier to life, engineers plan a series of telescopes, launched several years apart, with different but interlocking missions.
First will come the Space Infrared Telescope Facility, tentatively scheduled for launch in 2001. Designed to view the universe in shades of red the human eye can't see, SIRTF will be able to pierce clouds of gas and dust to find stars and solar systems forming within. It will also be able to see ``superplanets,'' gas giants several times larger than Jupiter.
Next comes the Space Interferometry Mission, which will combine images from several small telescope mirrors to simulate a very large one. The resulting image will be so sharp that astronomers should detect wobbles, in nearby stars, caused by planets almost as small as Earth.
Then, more than a decade down the road, JPL hopes to launch the series' crowning achievement: a wish-list of a telescope called the Terrestrial Planet Finder. With an array of mirrors mimicking one as large as a football field, TPF will be able to actually see planets the size of Earth, a feat never before accomplished.
All three will work in concert. SIRTF will identify recently formed or forming solar systems by finding dust disks around nearby stars. SIM will then scan the insides of those disks and check for tell-tale stellar wobbles. Finally, TPF will zoom in on solar systems found by the other telescopes. It will hunt for planets warm enough - but not too warm - to hold liquid water and possibly life.
The goal, Beichman said, is a thorough survey of our stellar neighborhood.
``We'll be able to do a census of the nearest 1,000 stars,'' he said. ``You'll have a sense of where the planets are, and whether they're in the zone that can support life.''
Before the census can begin, JPL engineers first must clear several technical hurdles. The Planet Finder mission, for example, relies on largely untested technology. Its multiple mirrors may sit on a single boom or on separate spacecraft flying in formation.
And in keeping with NASA's slimmed-down budget, these innovations must be achieved on what Hubble's designers would have considered a shoestring. SIRTF's budget is $450 million, a fraction of the more than $3 billion that went into Hubble. SIM will cost $480 million, while TPF, still in the early design stages, doesn't yet have a budget.
Still, Beichman said that changes in technology since the older space telescope's creation should help make the new observatories smaller and cheaper to build.
``The computers on Hubble were the size of a bookshelf,'' he said. ``And they did less than your laptop, your laptop from eight years ago.''
PHOTO (1) JPL's Charles Beichman and Firouz Naderi look at a model of one of the telescopes being developed to replace the aging Hubble.
(2) The Orbiting Optical Interferometer may be able to detect planets in new worlds.
Hans Gutknecht/Daily News
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|Publication:||Daily News (Los Angeles, CA)|
|Date:||Feb 15, 1998|
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