After more than 25 years of stratospheric snooping, the world's fastest and highest-flying planes have begun making their final flights this week -to museums across the country.
The 20 or so dagger-shaped Blackbird spy planes, which have photographed countries from Vietnam to Nicaragua, have been grounded by cuts in military spending as well as technological advances that enable satellites to do similar work for less money.
But some members of Congress and some critics in the Air Force warn that the loss of the planes, which cost as much as $400 million a year to maintain, leaves a gap in the nation's reconnaissance at a time when compliance with arms-control treaties now being negotiated will have to be verified from the sky.
Three decades after it was designed by Lockheed, the SR-71 Blackbird is still regarded as a technological wonder. It can outrun the fastest fighter jets and any missiles fired at it. Skirting the edge of space at altitudes of nearly 100,000 feet, the unarmed plane has never been shot down, although hundreds of attempts have been made.
''If we were getting shot at, we wouldn't bank or dive - we'd simply increase speed,'' said one pilot. ''In 30 seconds we could outrun anything.''
Made almost entirely of titanium, the Blackbird's skin is no thicker than a soda can's. The jet's two engines produce thrust equivalent to that of the Queen Mary's. And the plane carries an array of sensors and cameras capable of photographing the numbers on a license plate from 15 miles up.
Even as the Blackbird is being relegated to museums, details of the plane have been kept a mystery. The Air Force says its top speed is 2,100 miles an hour. But pilots who have flown the plane said it could go 2,600 miles, coast to coast, in an hour.
Perhaps the most famous photographs from the Blackbird came from one of its first missions, when it recorded China's first tests of a nuclear bomb in the 1960's. In 1982 its photographs revealed the presence of Soviet MIG's in Nicaragua, setting off an international dispute. In 1973 it helped verify compliance with the cease-fire in the Arab-Israeli war. The plane was used to assess damage in Libya after the United States bombing in 1987.
While the Air Force will not disclose how much it costs to maintain the planes, estimates range from $250 million to $400 a million a year - as much as it costs to maintain 90 fighter jets. The fuel-guzzling Blackbird needs as many as six refueling planes as escorts on a long mission.
The Bush Administration said it ended the program because of improvements in satellites for spying. The decision last fall was undoubtedly also part of the cutbacks flowing from eased relations with the Communist bloc. But the more versatile Blackbird can photograph a larger area in less time than satellites, which are locked into specific orbits and may have to wait days to pass over a trouble spot. And the plane is less hindered by clouds and darkness than are satellites.
Some Air Force officials said the program was ended because the Air Force viewed it as a liability. Although its operations were paid for by the Air Force, the decision of when and where to fly it rested with the Central Intelligence Agency, National Security Agency and the Defense Intelligence Agency. ''The plane does nothing for the Air Force,'' said an Air Force officer involved with the program, who asked not to be identified. ''It doesn't drop bombs or shoot missiles.''
Decision Sharply Criticized
''It's a national travesty,'' said a high-ranking Air Force officer, who asked not to be identified, of the elimination of the Blackbird.
The Blackbird's predecessor was the U-2 spy plane. First flown in 1955, the U-2 is best known for its darkest day; in May 1960 Francis Gary Powers was shot down and later captured by the Soviets. The U-2 flies lower and much more slowly than the Blackbird, reaching speeds of less than 700 miles per hour.
The Air Force will continue to fly versions of the U-2, which costs much less to maintain than the Blackbird. U-2 funds come from outside the Strategic Air Command's budget. Therefore, the plane competes for money with other intelligence resources like satellites.
Rumors have circulated that the Air Force is developing a new spy plane, code-named Aurora, capable of flying five times the speed of sound, or 3,800 miles per hour. But the Air Force denies its existence.
Of the approximately 20 Blackbirds left (even that number is still classified), nine will go to museums, three will be used by NASA for research and three will be mothballed in Palmdale, Calif., to be recalled in emergencies. The fate of the other planes was not clear.
Pilot Bemoans Life in Slow Lane
The small band of Blackbird pilots, accustomed to traveling faster than a bullet, are finding it difficult adjusting to their slower assignments. ''After this, it's going to be hard going on to anything else,'' said Maj. Dan Watkins, the last to be trained to fly the Blackbird.
The first decommissioned Blackbird was delivered Thursday to Robins Air Force Base in Georgia. Blackbirds will also be displayed at the National Air and Space Museum in Washington and the Air Force Museum at Wright Patterson Air Force Base in Ohio, and at Offutt Air Force Base in Nebraska, Lackland in Texas, and Edwards, March, Castle and Beale in California.
Next month one plane that will be displayed at the National Air and Space Museum will attempt to set a coast-to-coast speed record, flying from Palmdale to Washington in less than an hour.
At first, the Air Force turned down the request for a record run, agreeing to it only after pressure from the museum and some members of Congress.