To get there will require more than a rocket. The fledgling spaceliners will need to park their ships once they arrive at their destinations.

An engineering test NASA plans for this week should, if successful, provide a good starting point.

The Demonstration of Autonomous Rendezvous Technology, or DART, is NASA's attempt to develop what the Russian space program has been building and flying for decades: an automated docking system for spacecraft.

Beginning with the Gemini program, which served as the buildup for the Apollo moon missions in the late 1960s and early 1970s, NASA has opted to put a pilot in the loop for rendezvous and docking spacecraft.

The first attempt to bring together two orbiting spacecraft was in March 1966 during the Gemini 8 mission.

Pilots Neil Armstrong and David Scott successfully docked their capsule with an unmanned Agena target vehicle, but the milestone quickly was overshadowed by an inflight emergency.

About 27 minutes after docking, a stuck thruster on the Gemini vehicle sent the connected ships into a wild spin and roll.

With the Gemini capsule near its structural limits, and with the pilots about to pass out from the gyrations, Armstrong undocked from the Agena, thinking that would solve the problem.

"It only made it worse," recounts space historian Mark Wade, in Encyclopedia Astronautica, an online space reference publication.

When the capsule started rolling again, the crew decided to shut down the main orbital steering system and use their re-entry rockets to settle the ship.

The plan worked, but left the crew short of fuel for the rest of the planned flight. Flight controllers called for an emergency landing and the crew splashed down safely in the Pacific Ocean less than 12 hours after launch.

Ultimately, the astronauts of Gemini 11 and 12 each successfully rendezvoused and docked with an Agena, setting the stage for the Apollo program.

These maneuvers allowed the Apollo astronauts to descend to the surface of the moon in the Lunar Module, then return safely to their orbiting mother ships for the journey back to Earth.

Since then, not much has changed. NASA developed similar systems to berth its space shuttles at the Russian space station Mir in the mid-1990s, and later to the International Space Station.

On Friday, though, the agency plans to take its first steps toward a new, unmanned docking system.

"The goal of DART is to basically have an autopilot," Jim Snoddy, DART manager, said during a prelaunch news conference.

The project, which was managed by Marshall Space Flight Center, began in 2001 and has included extensive ground tests, as well as flight tests of laser ranging systems during two space shuttle missions.

"It does work," project spokeswoman Kim Newton, with Marshall Space Flight Center, said in an interview with UPI's Space Race 2. "They've completed it time and time again on the ground."

Friday's test begins with the spacecraft's release from its launch vehicle, an air-launched Pegasus booster, built by Orbital Sciences.

Pegasus is mounted beneath the wing of a modified L-1011 aircraft, which will take off from California's Vandenberg Air Force Base, northwest of Los Angeles.

Once in position, about 100 miles from the California coast and 40,000 feet in altitude, the rocket will be dropped and then will fire its engines to catapult DART into a 300-mile high parking orbit.

After a spacecraft checkout, DART is to fire its own booster to climb another 170 miles higher, where it will begin tracking its target, which should be about 24 miles in front of and 4 1/2 miles above DART.

DART is programmed to attempt about 50 close encounters over the next 24 hours with one of a trio of military satellites, an experimental communications craft called Multiple Paths, Beyond Line-of-Site Communications or MUBLCOM.

The target satellite is equipped with two sets of reflectors to bounce back DART's laser beams. DART will use the information to determine its position relative to MUBLCOM, and attempt to close in on the satellite.

DART also will make use of an onboard global positioning system for navigation.

DART is expected to run through a preprogrammed set of rendezvous maneuvers, including flying around the satellite, moving in close, backing away and descending from above the spacecraft.

For its debut test flight, DART will not come closer than about 16 feet to MUBLCOM.

"Once DART is launched it's gone," Newton said. "It's totally autonomous. It can correct itself."

Before its battery power runs out, DART is programmed to put itself in position to re-enter Earth's atmosphere and fire its engines. The spacecraft will be incinerated to avoid becoming another piece of space junk orbiting Earth.

Data relayed during the test will be analyzed by researchers and applied to future missions to test automated dockings in space.

"Whether you're going to the moon or Mars, you're always going to have to put things together in space," Snoddy said. "This technology will become more important as we get farther away from Earth."

"It's a very early prototype for now, but it has applications to anything that could use autonomous rendezvous in space," Newton added.

Space Race 2 is a weekly series by UPI exploring the people, passions and business of private human spaceflight written by long-time aerospace journalist Irene Klotz. E-mail [email protected].

All rights reserved. � 2005 United Press International. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by United Press International. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of United Press International.

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