Inside a cramped mountaintop observatory, Eleanor (Glo) Helin scans pictures of the sky, looking for asteroids that someday could wipe out the human race.
"I certainly don't want to frighten anyone or cause great alarm. It's not that I'm rattling any cage saying, 'Tomorrow we will die.' But we have been impacted before and we will be impacted again. We need to be prepared."
Such doomsday thoughts usually are far from Helin's mind as she works in the small, white dome that houses the 18-inch Schmidt telescope at Palomar Observatory on the 6,100-foot mountaintop northeast of San Diego.
Instead, Helin concentrates on discovering asteroids and comets.
In 20 years of spending long, cold nights at observatories around the world, Helin has discovered almost 80 "near-Earth asteroids." That's more than any other person, said Brian Marsden, director of the Central Bureau for Astronomical Telegrams, an astronomy reporting agency.
Asteroids are large rocks, and comets are a mixture of rock and ice--both leftovers from the formation of the solar system 4.6 billion years ago. Most asteroids orbit the sun in the main asteroid belt between the orbits of Mars and Jupiter. Near-Earth asteroids are those with unusual orbits that occasionally bring them close to Earth. Some comets and near-Earth asteroids have smashed into Earth with the power of hundreds of thousands of nuclear bombs.
Increasing evidence suggests such a collision occurred 65 million years ago. It devastated thousands of square miles and hurled enough dust skyward to block sunlight, chill the Earth's climate, destroy food plants and cause mass extinction of the dinosaurs and many other species. Many smaller impacts have occurred since then.
A 1992 NASA report estimated there is a 1-in-10,000 chance another such calamity could happen during our lifetime, and that it could "possibly end civilization as we know it" and perhaps threaten "survival of the human species." A smaller asteroid could wipe out a city and kill millions, said the report, which Helin helped write.
Helin and members of her team also discovered 14 comets and nearly 2,000 asteroids in the main asteroid belt. She also set up a search that found an additional 1,200 main-belt asteroids.
"It's the process of discovery that turns her on," said a longtime friend, Bruce Murray, a professor at Caltech and former director of JPL. "Not many people in their lives get a chance to find things no one else knows about."
Helin's rise to the top of her field didn't come easily. It took years of grueling work, perseverance and public relations skill to earn respect from the men who dominate astronomy and to show why asteroids are important. Such objects once were considered "vermin of the skies" because they blemished photographs of distant stars.
"She's gone up against some pretty tall brick walls as far as being a woman in science," said her son, Bruce, who outfits river running trips in Arizona.
On a recent night at the telescope dome, country music twanged from a radio as Helin used a stereomicroscope to scan a pair of film plates exposed through the telescope the previous night.
Her three assistants were busily loading and unloading the telescope's film canisters, developing the plates and darting outside to check for thin clouds that ruin the view.
To find asteroids and comets, a targeted area of the sky is photographed twice, about 30 minutes apart. Unlike stars, any asteroids or comets will have moved significantly between the two exposures, so their images won't be superimposed when the two plates are viewed through the stereomicroscope. It takes Helin half an hour to scan each pair of plates.
The low-tech nature of Helin's search for asteroids is striking. She uses an old telescope, photographic film and her own eyes. The Schmidt is the smallest and oldest telescope at Palomar.
But it has allowed Helin to discover more and more asteroids, including some that are candidates for exploration by NASA spacecraft and that someday could provide minerals or fuel to space travelers.
In the 1992 NASA report, Helin and others recommended spending $50 million to build six moderate-size, high-tech telescopes. The report said that in 25 years the telescopes could find 90% of the asteroids and comets capable of causing global catastrophe.
Some scientists advocate using nuclear warheads to deflect incoming asteroids. But Helin isn't convinced a killer rock could be deflected or that the impact site could be identified and evacuated without causing mass panic.
She believes there is a good chance that an asteroid up to the size of a football field could hit Earth within the next century.
"That's a city-destroyer," she said. "We don't know when and where that object may be lurking."
Helin lives with her husband, Ron, in Thousand Oaks. She prefers not to reveal her age but is believed to be about 60.
Although gregarious by nature, she can be tough if need be.
"When she wants to turn on the charm, she is an absolute charmer," but when she feels mistreated, "she can turn off the friendliness really fast," said U.S. Geological Survey geologist Eugene Shoemaker, once Helin's mentor and now a rival asteroid hunter.
"She's not an easy person," said Helin's husband, a retired engineer. "She's tough. She has to be."
"She lives and breathes near-Earth asteroids, but gives you the image of an ordinary woman you would meet shopping," said Louis Friedman, executive director of the Planetary Society, which helps finance Helin's research.
Eleanor Francis Helin, an only child, was born Eleanor Kay Francis in Pasadena. At the age of 5, she was stricken by polio, leaving her bedridden for months.
"It made me more determined," she said.
Helin attended school in Altadena and Pasadena, then went to Occidental College in Los Angeles, where she studied geology and married Ron Helin.
She later studied and worked at Caltech, where she and Murray established the lunar research lab in 1960 to help prepare for NASA moon missions. Her study of lunar craters and meteorites that hit Earth got her interested in asteroids, the source of many meteorites.
In the late 1960s, she began studying near-Earth asteroids while working for Shoemaker at Caltech. She discovered her first near-Earth asteroid July 4, 1973.
In 1980, geologist Luis Alvarez and colleagues at UC Berkeley found rock deposits that suggested an asteroid or comet wiped out dinosaurs and other creatures.
The same year, Murray brought Helin to JPL. A rivalry between Helin and Shoemaker developed, partly because of disagreements over who got credit for asteroid research.
In 1982, Shoemaker and his wife started a competing search. Helin and the Shoemakers now share the 18-inch telescope at Palomar, each using it one week a month. The Shoemakers have discovered a record 27 comets. The world's only other systematic search for near-Earth asteroids is run by Tom Gehrels at Arizona's Spacewatch Telescope.
For a decade, Helin has roamed the globe organizing asteroid searches in France, Australia, Bulgaria, Russia, Britain, Italy and Japan.
"With perseverance and instinct and ingenuity, she has managed to get observing time on observatories all over the world," Murray said.
Most of Helin's annual budget of about $200,000 comes from the National Aeronautics and Space Administration. But she forged a network of donors that includes the World Space Foundation, the Planetary Society and affluent individuals.
"She's selling herself all the time," Shoemaker said. "She spends a lot of time thinking about how to sell what she's doing and, by God, she's sold it."
Helin has become "very good at public relations," Marsden said, and it's paid off.
Her biggest public relations campaign involves naming asteroids.
Under International Astronomical Union tradition, near-Earth asteroids are named after mythological gods. But astronomers who discover main-belt asteroids can name them for real people. A colleague named one Glo to honor Helin.
Helin named asteroids for friends and financial supporters. They include Marvin Goldberger, then a president of Caltech; Thomas Paine, once NASA's administrator; Rob Staehle, head of the World Space Foundation; Friedman of the Planetary Society; Lew Allen, a former JPL director, and the son of ex-JPL director Murray.
"Glo has used her naming of asteroids for political purposes from Day 1," Shoemaker said. "She's gone out of the way to convey these favors on people of authority and prestige, including people who fund the (asteroid) program. It works. And I was a party to it as well."
Helin said naming asteroids for donors is a century-old tradition. "You recognize friends and people who have helped you," just like colleges name buildings to honor contributors, she said.
Helin takes particular pride in the name she gave an asteroid she discovered Sept. 10, 1978.
Its temporary designation was 1978 RA. By coincidence, Ra was the name of the Egyptian sun god. That gave Helin an idea. President Carter had just helped forge the Camp David peace accord between Israel and Egypt. So Helin named the asteroid Ra-Shalom, after the sun god and the Hebrew word for peace.
Plaques showing asteroid Ra-Shalom and commemorating the peace accord were presented to the leaders of Israel and Egypt.