HUALAPAI INDIAN RESERVATION, Ariz. - Indian leaders and former astronauts stepped gingerly beyond the Grand Canyon's rim Tuesday, staring through the glass floor and into the 1,200-metre chasm below during the opening ceremony for a new observation deck.

A few members of the Hualapai Indian Tribe, which allowed the Grand Canyon Skywalk to be built, hopped up and down on the horseshoe-shaped structure. At its edge -- 22 metres beyond the rim -- the group peeked over the glass wall.

"I can hear the glass cracking!" Hualapai Chairman Charlie Vaughn said playfully.

The deck is anchored deep into a limestone cliff. As people walk across it, the glass layers creak and the deck wobbles almost imperceptibly. To one side, the Colorado river appears as a slim, pea-green ribbon. To the other is a triangular dip in the canyon's ridge, known as "Eagle Point" because it looks like a bird with outstretched wings.

When the wind blows, only the most daring visitors resist grabbing the steel rail to steady their knees.

Former astronaut Buzz Aldrin, who was invited to join the tribe along with former astronaut John Herrington, declared it a "magnificent first walk."

"It felt wonderful; not exactly like floating on air," Aldrin said after stepping off the deck.

The Hualapai, whose reservation is about 150 kilometres west of Grand Canyon National Park, allowed Las Vegas developer David Jin to build the US$30 million Skywalk in hopes of creating a unique attraction on their section of the canyon.

"To me, I believe this is going to help us. We don't get any help from the outside, so, why not?" said Dallas Quasula Sr., 74, a tribal elder who was at the Skywalk. "This is going to be our bread and butter."

The tribe will include access to the deck in a variety of tour packages ranging from $49.95 to $199.00. They'll allow up to 120 people at a time to look down to the canyon floor more than 1,200 metres below, a vantage point more than twice as high as the world's tallest buildings.

The Skywalk is scheduled to open to the public March 28.

To reach the transparent deck, tourists must drive drive 22 kilometres on twisty, unpaved roads. But the tribe hopes it becomes the centerpiece of a budding tourism industry that includes helicopter tours, river rafting, a cowboy town and a museum of Indian replica homes.

Robert Bravo Jr., operations manager of the Hualapai tourist attractions called Grand Canyon West, said he hopes the Skywalk will double tourist traffic to the reservation this year, from about 300,000 visitors to about 600,000.

Architect Mark Johnson said the Skywalk can support the weight of a few hundred people and will withstand wind up to 160 kilometres per hour. The observation deck has a 7.5-centimetre-thick glass bottom and has been equipped with shock absorbers to keep it from bouncing like a diving board as people walk on it.

The Skywalk has sparked debate on and off the reservation. Many Hualapai worry about disturbing nearby burial sites, and environmentalists have blamed the tribe for transforming the majestic canyon into a tourist trap.

Hualapai leaders say they weighed those concerns for years before agreeing to build the Skywalk. With a third of the tribe's 2,200 members living in poverty, the tribal government decided it needs the tourism dollars.

Dolores Honga, 71, a tribal elder, said she used to ride horses around what used to be a remote patch of grassland. Her grandparents once herded cattle out here.

"I still don't agree with what's going on here," Honga said. "There's so many memories here. This was my playground."

Jin fronted the money to build the Skywalk, which took two years to construct. According to the tribe, Jin will give it to the Hualapai in exchange for a cut of the profits.

"The terms are confidential, but David will profit for the next 25 years from the Skywalk," said Steve Beattie, chief financial officer of the Grand Canyon Resort Corp., which oversees the tribe's tourist businesses.