SPACE.com -- NASA's Robotic DART Mission Ends in Mishap

An Orbital Sciences-built Pegasus XL rocket successfully orbited NASA's autonomous DART spacecraft on April 15,2004 during an air-launch staged from a Stargazer L-1011 carrier aircraft flying over the Pacific Ocean. Credit: NASA TV. Click to enlarge.

An artist's concept of the DART spacecraft as it bears down on its target satellite in orbit. Credit: Orbital Sciences. Click to enlarge.

NASA's autonomous DART spacecraft (left) sits next to the Orbital Sciences-built Pegasus rocket that launched the autonomous test vehicle into orbit on April 15, 2005. Credit: Orbital Sciences. Click to enlarge.

NASA's Replay of DART Spacecraft's Launch


	NASA's Robotic DART Mission Ends in Mishap By Justin Ray

SATURDAY, APRIL 16, 2005

NASA's $110 million high-risk, high-tech demonstration of a space autopilot for future human spaceships and robotic cargo craft closed within 300 feet of its target Friday night, then inexplicably ran out of fuel to the dismay of helpless engineers on the ground. Read our full story.

1829 GMT (2:29 p.m. EDT)

NASA's Demonstration of Autonomous Rendezvous Technology spacecraft ran out of fuel as it approached its target satellite for autopilot tests last night, the program manager told reporters in a news conference a short time ago. It is not clear why DART used substantially more thruster propellant than envisioned, but officials saw the craft was fighting some guidance errors earlier in the mission.

DART was designed to perform two series of maneuvers around the target satellite, plus featured a 30 percent fuel margin, Jim Snoddy said. But the satellite safed itself at a distance of 92 meters from the MUBLCOM satellite instead of closing within five meters and later performing the flyaround demonstrations.

Sensing it didn't have enough fuel to continue with the mission, DART backed away and began its "retirement" procedures. The craft is supposed to fire engines and deplete its hydrazine fuel in the next half-hour or so, thereby moving into a disposal orbit and formally concluding the $110 million flight.

Check back later for a complete report.

1446 GMT (10:46 a.m. EDT)

MISSION PROBLEM. The DART spacecraft suffered a problem after reaching its target late Friday, failing to complete the planned demonstrations. The satellite went into its "retirement" mode, ending the $110 million test early.

The mission was supposed to last nearly 24 hours before expending battery life and onboard fuel supplies.

"After a successful rendezvous, acquisition of the target spacecraft, and approach to within approximately 300 feet, DART placed itself in the retirement phase before completing all planned proximity operations, ending the mission prematurely," NASA announced a short time ago.

"NASA is convening a mishap investigation board to determine the reason for the DART spacecraft anomaly," the statement said.

The space agency plans a news conference later today.

FRIDAY, APRIL 15, 2005
1905 GMT (3:05 p.m. EDT)

Ground teams have received early batches of data from DART, which reveal the spacecraft is performing well, a NASA spokesman says.

The spacecraft is on course to rendezvous with the MUBLCOM target satellite later tonight.

The entire mission of DART lasts just one-day and finishes with the craft completing a "retirement" engine firing to reach a disposal orbit where it will circle Earth for the next decade or two before re-entering the atmosphere and burning up.

1810 GMT (2:10 p.m. EDT)

NASA's Demonstration of Autonomous Rendezvous Technology spacecraft is alive and operating following its successful delivery into polar orbit today by the air-launched Orbital Sciences Pegasus XL rocket.

The satellite is controlling itself with absolutely no human touch. The revolutionary autopilot technologies will either make or break the mission.

"It'll be an interesting mission where you'll really have no control of your mission once you let go of it, but that's what the technology's all about," said Jim Snoddy, DART project manager from NASA's Marshall Space Flight Center.

NASA expects to release a couple of status updates during the DART rendezvous tests over the next 24 hours. Watch this page for the latest.

Below is a preview of the mission:

DART's sophisticated systems will locate the U.S. military's retired MUBLCOM communications satellite and rendezvous with the five-year old craft to demonstrate autopilot concepts. Over a one-day period, DART is programmed to perform a series of maneuvers around the target before concluding the $115 million mission.

The mission timeline called for a checkout of onboard systems starting about 30 minutes after launch. The craft then begins trek to reach its target, which will take about 7 hours or so. The science phase of the DART project to navigate in and around MUBLCOM begins about 8 hours after launch and continues through tomorrow.

"About 21 hours into the mission, God willing, we complete everything," Snoddy said.

If successful, DART will mark the first autonomous rendezvous conducted without any human involvement in U.S. space program history.

"DART is totally autonomous. There is no ability for human intervention," Snoddy said. "Of course systems of the future will want human intervention but DART was not designed to do that just to show that we could put all of these events together is a 24-hour timeline."

The 800-pound, 6-foot DART spacecraft uses its futuristic "brain" and "eye" to smartly chase down the target satellite and maneuver within feet of the object.

"DART has the ability to fire lasers, calculate precise distances down to millimeters to bring two objects together in space. Currently we don't have the technology to do that with a high degree of autonomy and accuracy, and six degrees of freedom so that we can know the X, Y and Z coordinates and be able to have vehicles with pitch, yaw and roll and bring those together with precise accuracy in space."

NASA developed the DART mission to test autopilot capabilities for the now-cancelled Orbital Space Plane project. But the technology is considered valuable for future human spacecraft, cargo-carrying resupply ships and satellite servicing concepts.

"DART is unique relative to the president's vision of going back to the moon and to Mars. We are going to have to put things together in space whether they be for cargo or crews," Snoddy said.

"It is kind of like in the airline industry. You have a pilot but you always want an autopilot. I think of DART kind of like an autopilot. You have the ability to have all of these things automated, so if you have an astronaut and want the autopilot to take over that is fine. But if you have cargo or things like that, you don't have (an astronaut) so you need this autopilot to also be there."

1756 GMT (1:56 p.m. EDT)

The L-1011 has landed safely.

1752 GMT (1:52 p.m. EDT)

Baez said the launch team experienced some communications trouble with the flight termination system prior to drop from the L-1011, but that was cleared up. Otherwise, it was a hectic final minutes of the countdown that culminated with a good launch and successful arrival into orbit for the DART mission.

1752 GMT (1:52 p.m. EDT)

"The launch success today has been incredible," NASA Launch Manager Omar Baez says.

1741 GMT (1:41 p.m. EDT)

T+plus 14 minutes. DART has flown out of range from communication networks. The next tracking station to acquire will be McMurdo located in Antarctica in about 15 minutes.

1739 GMT (1:39 p.m. EDT)

T+plus 12 minutes, 20 seconds. The HAPS upper stage has finished its initial firing. The $110 million DART mission is underway!

1738 GMT (1:38 p.m. EDT)

T+plus 11 minutes, 50 seconds. The hydrazine-fueled upper stage, which remains attached to DART for the mission, has ignited.

1738 GMT (1:38 p.m. EDT)

T+plus 11 minutes, 45 seconds. Separation from third stage confirmed.

1737 GMT (1:37 p.m. EDT)

T+plus 10 minutes, 40 seconds. Reorientation for separation between the spacecraft and third stage has been performed.

1736 GMT (1:36 p.m. EDT)

T+plus 9 minutes, 50 seconds. The third stage has burned out. An initial orbit has been achieved.

1736 GMT (1:36 p.m. EDT)

T+plus 9 minutes, 30 seconds. Velocity has surpassed 14,000 miles per hour as the third stage continues to burn.

1736 GMT (1:36 p.m. EDT)

T+plus 9 minutes, 10 seconds. The third stage firing at normal pressure.

1735 GMT (1:35 p.m. EDT)

T+plus 8 minutes, 50 seconds. Power systems remain strong.

1735 GMT (1:35 p.m. EDT)

T+plus 8 minutes, 40 seconds. The spent second stage has separated. And the solid-fueled third stage motor has ignited, accelerating the DART spacecraft to orbit.

1734 GMT (1:34 p.m. EDT)

T+plus 7 minutes, 50 seconds. The reorienting is complete.

1734 GMT (1:34 p.m. EDT)

T+plus 7 minutes, 35 seconds. The vehicle is now reorienting in preparation for stage separation and third stage burn.

1734 GMT (1:34 p.m. EDT)

T+plus 7 minutes, 15 seconds. The ballistic coast period continues for Pegasus. About 90 seconds remain until third stage ignition.

1733 GMT (1:33 p.m. EDT)

T+plus 6 minutes, 20 seconds. Altitude is now 380 miles and still climbing toward the current suborbital trajectory's high point where the second stage should be jettisoned and third stage motor ignited.

1732 GMT (1:32 p.m. EDT)

T+plus 5 minutes, 15 seconds. The rocket remains in a normal attitude. The power systems remain in good shape.

1731 GMT (1:31 p.m. EDT)

T+plus 4 minutes, 15 seconds. Third stage ignition is now calculated to occur at approximately T+plus 8 minutes, 36 seconds. The start time based upon the performance of the vehicle's first two stages.

1730 GMT (1:30 p.m. EDT)

T+plus 4 minutes. Altitude is currently 150 miles, traveling at 12,000 miles per hour.

1729 GMT (1:29 p.m. EDT)

T+plus 2 minutes, 45 seconds. The solid-fueled second stage has burned out. The Pegasus rocket is now in a coast period for the next few minutes. During this time the rocket will compute the performance of the flight thus far and adjust the third stage ignition time if necessary.

1729 GMT (1:29 p.m. EDT)

T+plus 2 minute, 10 seconds. The two halves of the payload fairing enclosing the DART satellite on the end of the Pegasus rocket has been jettisoned. Second stage continues to burn.

1728 GMT (1:28 p.m. EDT)

T+plus 1 minute, 45 seconds. Altitude is 50 miles.

1728 GMT (1:28 p.m. EDT)

T+plus 1 minute, 30 seconds. The first stage is jettisoned. The Pegasus' second stage has ignited.

1728 GMT (1:28 p.m. EDT)

T+plus 1 minute, 18 seconds. The solid-fueled first stage has burned out. The vehicle is now in a ballistic coast for a few seconds before the spent stage is jettisoned and the second stage ignites.

1727 GMT (1:27 p.m. EDT)

T+60 seconds. The rocket is over 100,000 feet in altitude.

1727 GMT (1:27 p.m. EDT)

T+plus 45 seconds. The Pegasus rocket is passing through maximum dynamic pressure. Attitude of the vehicle is reported normal.

1727 GMT (1:27 p.m. EDT)

T+plus 30 seconds. The Pegasus rocket is pitched up 35 degrees as it climbs into the sky on the power of its solid-fueled first stage motor at over 1,500 mph.

1726:57 GMT (1:26:57 p.m. EDT)

IGNITION of the Pegasus rocket launching NASA's Demonstration of Autonomous Rendezvous Technology satellite to test autopilot capabilities that will benefit space explorers of the future.

1726:52 GMT (1:26:52 p.m. EDT)

DROP. The Orbital Sciences Pegasus XL rocket has been released from the L-1011 aircraft off the California coastline.

1726 GMT (1:26 p.m. EDT)

The batteries for the first stage flight control fins have been activated, allowing the fins to undergo a sweep test prior to launch. The fins are used to steer the rocket during its initial climb to space.

With the batteries activated there is just 90 seconds to launch today or else an abort will be called. That is due to the limited life of the batteries.

In the final moments prior to release of Pegasus, the L-1011 carrier aircraft crew will oversee the last seconds of the countdown and flip the switch that will drop the vehicle, with the DART spacecraft aboard, from the belly of the jet.

1724 GMT (1:24 p.m. EDT)

Launch is about two minutes away.

1724 GMT (1:24 p.m. EDT)

The launch team confirms the SIGI onboard flight computer is configured.

1723 GMT (1:23 p.m. EDT)

The rocket's SIGI guidance computer is being configured for flight now. The earlier difficulty appears resolved.

1722 GMT (1:22 p.m. EDT)

The launch team has been given a "go" to enter the final phase of the countdown at L-minus 4 minutes.

1722 GMT (1:22 p.m. EDT)

T-minus 4 minutes. Countdown is running a few minutes behind schedule.

1721 GMT (1:21 p.m. EDT)

The Pegasus rocket's avionics have switched from power provided by the L-1011 to internal battery power.

1721 GMT (1:21 p.m. EDT)

The Air Force confirms the Range is clear for the launch.

1720 GMT (1:20 p.m. EDT)

Checks of the flight termination system have been completed. The Range reports the results were nominal.

1720 GMT (1:20 p.m. EDT)

The Air Force launch weather officer confirms conditions are "go."

1718 GMT (1:18 p.m. EDT)

NASA Launch Manager Omar Baez has polled his team for the "go" to enter terminal count.

1716 GMT (1:16 p.m. EDT)

The Pegasus launch controller aboard the L-1011 is reporting a problem on his console display when trying to switch the rocket flight computer to internal power.

1716 GMT (1:16 p.m. EDT)

L-1011 has maneuvered to the proper heading for launch.

1715 GMT (1:15 p.m. EDT)

The SIGI flight computer is going to internal power.

1714 GMT (1:14 p.m. EDT)

The flight termination system is now running on internal power. The safety system would be used to destroy the Pegasus rocket in the event a problem during launch.

1713 GMT (1:13 p.m. EDT)

The launch team members report they are ready to switch the rocket's flight termination system to internal power.

1710 GMT (1:10 p.m. EDT)

The drop mechanism that releases Pegasus from the belly of the L-1011 aircraft has been armed.

1705 GMT (1:05 p.m. EDT)

Now 20 minutes till launch. Today marks the 36th flight of the air-launched Pegasus rocket and the 26th using the XL version. This will be the first Pegasus launch in 20 months.

1700 GMT (1:00 p.m. EDT)

The carrier jet has passed through the launch point, verifying good weather conditions. The aircraft is heading northward right now but will soon make a wide, sweeping U-turn for return to the rocket drop zone on a southerly heading.

1657 GMT (12:57 p.m. EDT)

A chase plane flying beside the L-1011/Pegasus duo over the Pacific Ocean is performing a routine visual inspection of the rocket prior to launch.

1655 GMT (12:55 p.m. EDT)

The L-1011 is passing the P-Power waypoint.

1645 GMT (12:45 p.m. EDT)

The climb to altitude by the L-1011 and flight off the coast is progressing without trouble. The jet is flying a pre-determined "race track" pattern over the Pacific to reach the proper launch point where Pegasus will be released to roar into orbit.

1635 GMT (12:35 p.m. EDT)

Now 50 minutes from the scheduled launch of Pegasus.

The air-launched rocket will be released from the L-1011 jet over the Pacific Ocean west of California's central coast. Weather permitting, the rocket's exhaust trail should be visible to residents throughout central southern California as the Pegasus streaks southward on the trek to space.

1634 GMT (12:34 p.m. EDT)

"We are excited for a successful mission today," Jim Snoddy, DART project manager, just said. He indicated that all of the ground tracking stations for DART and the MUBLCOM satellite that serves as the target for this rendezvous mission are up and operating successfully today.

1627 GMT (12:27 p.m. EDT)

WHEELS UP. The "Stargazer" carrier aircraft with the Orbital Sciences Pegasus XL rocket has departed Vandenberg Air Force Base in California for today's launch to place NASA's DART spacecraft into orbit to test autopilot technologies.

1626 GMT (12:26 p.m. EDT)

The L-1011 is rolling down the runway.

1624 GMT (12:24 p.m. EDT)

A poll of the ground launch team has been completed by the Orbital Sciences launch conductor. Takeoff is just a few minutes away now.

1622 GMT (12:22 p.m. EDT)

NASA Launch Manager Omar Baez has polled the space agency team to verify all is in readiness for takeoff of the L-1011 aircraft. All remains "go" at this time.

1615 GMT (12:15 p.m. EDT)

NASA reports there are no issues with the Pegasus rocket, DART spacecraft, weather or downrange tracking assets. Launch remains targeted for 1725 GMT (10:25 a.m. local time; 1:25 p.m. EDT).

1603 GMT (12:03 p.m. EDT)

The Stargazer carrier jet has rolled from its staging area to the 10,000-foot long runway at Vandenberg Air Force Base in preparation for takeoff.

1530 GMT (11:30 a.m. EDT)

The Pegasus countdown lasts over four hours. Launch team members were expected to report for duty around 1300 GMT today to open the pre-flight checklist, which features a series of ground-based events such as final preparations to the payload, performing power tests on the rocket and checking the Range Safety's Flight Termination System. Engines of the L-1011 are scheduled to be started around this time in advance of the carrier aircraft doing its taxi to the runway.

1455 GMT (10:55 a.m. EDT)

All systems are "go" for this morning's launch of the DART spacecraft aboard the Pegasus rocket. Takeoff from the Vandenberg is expected around 1627 GMT (9:27 a.m. local time; 12:27 p.m. EDT) for the 58-minute flight to the launch point located 62 nautical miles west of Pebble Beach, about 40,000 feet over the Pacific Ocean.

THURSDAY, APRIL 14, 2005

A sophisticated spaceship autopilot will be launched into Earth orbit Friday to test high-tech equipment viewed critical to American exploration plans for returning to the moon and onward to Mars.

NASA's Demonstration of Autonomous Rendezvous Technology craft, called DART for short, will be blasted into space by the air-launched Pegasus XL rocket made by Orbital Sciences.

A modified L-1011 carrier aircraft ferries the Pegasus off the California coast from Vandenberg Air Force Base where the winged rocket will drop around 1725 GMT (10:25 a.m. local time; 1:25 p.m. EDT) about 62 nautical miles west of Pebble Beach.

It will take about 12 minutes to reach the intended orbit.

"We're recently glad to be back here and hopefully put this thing into space tomorrow morning," launch manager Omar Baez told reporters Thursday. "We finished our Launch Readiness Review this morning and we're really looking forward to launch tomorrow."

The mission has been delayed numerous times by a variety of technical concerns. It was supposed to fly last fall, but NASA grounded the launch to double-check the G-force loads the satellite would experience at ignition of the Pegasus second stage.

"This has been a long time in coming. People have been working on this project, developing technologies probably for 10 years now," said Jim Snoddy, DART project manager from NASA's Marshall Space Flight Center. "So I think the excitement is back up to the fevered pitch for one-day before launch."

"The rocket is in excellent condition, the L-1011 is ready to support and we're looking forward to a very uneventful launch," added Bryan Baldwin, Pegasus program director at Orbital Sciences.

DART's sophisticated systems will locate the U.S. military's retired MUBLCOM communications satellite and rendezvous with the five-year old craft to demonstrate autopilot technologies. Over a one-day period, DART is expected to perform a series of maneuvers around the target before concluding the $115 million mission.

"About 21 hours into the mission, God willing, we complete everything," Snoddy said.

If successful, DART will mark the first autonomous rendezvous conducted without any human involvement in U.S. space program history.

The 800-pound, 6-foot DART spacecraft uses its futuristic "brain" and "eye" to smartly chase down the target satellite and maneuver within feet of the object.

"DART is unique relative to the president's vision of going back to the moon and to Mars. We are going to have to put things together in space whether they be for cargo or crews," Snoddy said.

Watch this page for live updates during the countdown and launch.

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