The first hint that this is one of the first waystations in humanity's trek to the final frontier comes at check-in, where visitors are asked to sign in at "Visitor Control" -- a reference to NASA's Mission Control.

There's no better place to get up close to space exploration than Pasadena's Jet Propulsion Laboratory.

JPL is not a museum tailored to tourists such as the National Air and Space Museum in Washington. JPL will not awe you with the immense size of the vehicles used to escape the pull of Earth's gravity like the Kennedy Space Center at Cape Canaveral, Fla. It's a working lab, and JPL will give a live glimpse onto the world's most advanced engineering that's still allowing humans to view up close our planetary neighbors and beyond. It will remind you that some of the great discoveries, from the latter half of the 20th century to today, were made right here in Southern California.

Several years ago, actress Jodie Foster became so enamored with space at JPL while researching for her role of Eleanor Arroway in the 1997 movie "Contact" that she volunteered to serve as narrator for an updated version of the tour's 20-minute introductory film, JPL spokeswoman Jane Platt said.

And since 1999, the Academy Award-winning actress has told visitors of the space lab's achievements and its future projects, then bids them "Welcome to Outer Space."

This summer the space lab will ramp up its tour schedule to seven days a week, a makeup of sorts for the cancellation of its annual spring open house over post-Sept. 11 security concerns, JPL tour guide Marc Razze said.

Visitors to the space center run the gamut of knowledge. Some come because they have a curiosity for space. But the most obviously interested, and the ones with the widest smiles on tour, are those on who are space fans.

"I'm an engineer, a boat builder by trade ... and I have an interest in space mainly because of the fine engineering," said Allan Farrand, a visitor from Wahngarei, New Zealand. "I'm glad I got to see this stuff before I left."

Razze said now he's never surprised at the level of questions tossed at him from tourists.

For Farrand, the highlight of the tour was the visit to the Spacecraft Assembly Facility, "SAF" in the space lab's acronym-heavy culture.

The SAF visit takes the group into an enclosed viewing platform two stories above a room the size of a high-school gymnasium. The engineers below all don lab coats, gloves, booties and face masks to keep potentially damaging dust particles away from the multimillion-dollar spacecraft parts they're working on. Tour guides don't know what, if anything, will be on display at the assembly building. But on this particular day, the 40-person group had a real treat.

"We got to see the probe that will be on Mars, that's so cool," said Andrew Calhoun, 17, a high school student from Los Angeles who throughout the tour asked some of the most insightful questions.

The tour group was extremely lucky to see the NASA engineers are working on several key component to one of the Mars Exploration Rovers -- including the gold-colored rover and the protective flower petal shell that, with air bags, will cushion the 400-pound probe's fall to the Martian surface. A pair of rovers will be launched next year with both reaching the red planet in January 2004.

If they choose, visitors can sign their name into an unremarkable notebook that tells that the pages will be digitally scanned then carried on the Mars rover. So 18 months from now, your signature could find itself on Mars.

The tour's starting point shows one of JPL's proudest accomplishments -- a full-scale model of the Voyager spacecraft. Voyagers 1 and 2 were launched in 1977 and swung past Jupiter, Saturn, Uranus and Neptune, yielding stunning images of the gas giants.

The Voyager spacecrafts, now well beyond Pluto's orbit, as well as the JPL model come complete with the gold-plated record of Earth images, sounds greetings in 55 languages. Carl Sagan called it a bottle in the cosmic ocean. Of course, the extraterrestrials who find Voyager must still figure out how to play the record, from the diagramed instructions.

"It does assume some intelligence," Razze said.

Another stop on the tour is the lab's small museum. The most striking object is a full-scale model of the Gailieo spacecraft. Images from JPL's Earth-orbiting satellites are visible throughout the room.

The other stop includes the Space Flight Operations Facility, a mission control center. The ticking countdowns for spacecraft launches shown on the big screens overhead are really more show than anything else. They're usually only turned on for VIP dignitaries for launch parties or for tour groups that wander to the viewing platform.

And sometimes it isn't a spacecraft launch that has a countdown.

"On occasion if somebody retiring, there's a retirement countdown," tour guide Curtis Montano said.

JPL got its start in 1930s, when Caltech professor Theodore Van Karman took to the Arroyo Seco to conduct rocket experiments.

Under the U.S. Army, the lab's early work was on rockets and missiles, hence the name that sticks today. But the Soviet launch of Sputnik in 1957 in the middle of the Cold War would signal a watershed shift in JPL's mission.

The National Aeronautics and Space Administration was created in 1958 and shortly after JPL was transferred from the Defense Department to NASA with a new mission of the exploration of space.

Since then, JPL's story includes some of the most significant scientific achievements of the last 40 years.

JPL carried out the Mariner missions to Mercury, Venus and Mars; the Viking missions to Mars; and the Voyager missions to the outer planets.

In 1995, Gailieo gave us the spectacular views of comet Shoemaker-Levy 9 smashing into the Jovian Atmosphere with incredibly destructive force.

The failed Mars Polar Lander and the Mars Climate Orbiter in 1999 dealt the lab some setbacks. But it has had recent success with orbit of the Mars Odyssey craft, which will study chemical and mineral composition of the red planet.

JPL is now overseeing 13 space missions, including the high-profile Cassini mission to Saturn, expected to enter orbit at the ringed planet on July 1, 2004.

On board Cassini is the Huygens probe. It will be released to Saturn's largest moon, Titan. Titan's atmosphere includes organic compounds leading scientists to believe that the moon may have conditions similar to those on Earth before life began.

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FYI

Jet Propulsion Laboratory

Where: 4800 Oak Grove Drive, Pasadena, near the city's boundary with La Canada Flintridge

Tours: Tours are free, but reservations must be made four to six weeks in advance. Starting this month and through the summer, tours will be given seven days a week. Tours start at 9 a.m., 10 a.m., 1 p.m. and 2 p.m. The tours include a considerable amount of walking. Wheelchairs can be accommodated with advance notice. There are no restrictions on photography. Tours last two to three hours.

To reserve a tour: Contact JPL's Public Services Office at (818) 354-9314. Office fax is (818) 393-4641. Mailing address: Public Services Office, Mail Stop 186-113, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109.

Getting there: Take the 210 Freeway west to Pasadena. Exit at Berkshire Avenue/Oak Grove Drive. Turn right (east) on Berkshire Avenue to Oak Grove Drive. Go left at Oak Grove and head north to the laboratory entrance.

For information: www.jpl.nasa.gov

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JPL Fast Facts

-- JPL developed the Wide Field/Planetary Camera, the main viewing instrument for the Hubble Space Telescope. After a flaw was discovered in the telescope's main mirror, JPL built a second-generation camera that compensated for the problem, like fitting it with eyeglasses.

-- The space lab's first spacecraft was Explorer I in January 1958. The satellite operated for nearly four months.

-- To keep track of its spacecraft 24 hours a day, JPL must compensate for the Earth's daily rotation. It operates a communication network called the Deep Space Network. The network has centers at three points around the globe that are about 120 degrees apart. They are in the Mojave Desert, just outside Madrid, Spain, and near Canberra, Australia.

-- JPL has a work force of 5,400 employees and on-site contractors. Its annual budget is $1.4 billion.

-- The last in a quartet of Earth-orbiting observatories that included the Hubble Space Telescope will be launched in January. The Space Infrared Telescope Facility will peer into deep space through the infrared spectrum, because visible light is obscured by clouds and dust. The telescope must be cooled to near absolute-zero so heat won't interfere with its observations.