BY JUSTIN RAY

Follow the countdown and launch of the Boeing Delta 2 rocket with NASA's Swift gamma-ray burst detection observatory. Reload this page for the very latest on the mission.

THURSDAY, NOVEMBER 18, 2004
1535 GMT (10:35 a.m. EST)

The weather outlook for Saturday predicts a 90 percent chance of acceptable conditions during the launch window. You can read the full forecast here.

1510 GMT (10:10 a.m. EST)

Suspect parts in the Boeing Delta 2 rocket's safety system must be replaced, delaying until at least Saturday the launch of NASA's Swift gamma-ray observatory on its two-year mission to detect the most powerful explosions in the universe.

Saturday's launch window extends from 12:10 to 1:10 p.m. EST (1710-1810 GMT). Liftoff will occur from pad 17A at Cape Canaveral Air Force Station, Florida.

Last night, officials were targeting liftoff no sooner than Friday as engineers continued their efforts to isolate the source of a problem discovered in the rocket's Range safety destruct system. By this morning, ground support equipment had been eliminated and parts on the rocket were found to be the culprit, NASA said.

"The additional day was deemed necesarry overnight as workers determined the Range Command Receiver Decoder equipment on the launch vehicle is the likely reason for the voltage variance seen earlier this week and needs to be replaced," space agency spokesman Bruce Buckingham said.

"Workers will gain access to the equipment today and replace the necessary parts. The system will then be re-tested on Friday."

A mission management team meeting is planned for this afternoon to confirm the new launch date.

"We think there is a pretty good shot at Saturday," Buckingham said.

1440 GMT (9:40 a.m. EST)

NEW DATE. Launch of Swift is now targeted for no earlier than Saturday. The additional delay will give technicians time to replace Range safety equipment on the Delta 2 rocket. Saturday's launch time is 12:10 p.m. EST.

0208 GMT (9:08 p.m. EST Wed.)

Engineering teams continue to troubleshoot concerns with the safety system aboard the Boeing Delta 2 rocket that will carry NASA's Swift gamma-ray observatory into space, postponing liftoff from Cape Canaveral until Friday at the earliest.

Wednesday's initial launch opportunity was called off hours in advance after an issue was raised with the Command Receiver Decoder equipment on the Delta rocket at pad 17A. The system would receive signals from Range safety officers to destroy the vehicle during ascent if it went off course.

Launch crews were gearing up for a potential Thursday liftoff if the problem could be resolved in time. But officials decided a short time ago that another 24-hour delay in the launch was necessary.

"After a Wednesday evening management meeting, it was determined that a launch on Thursday was not possible due to the additional time required to continue assessments of the command receiver on the Delta. The launch team will continue analysis through the night, leaving open the possibility of a launch as early as Friday, November 19," NASA spokesman Bruce Buckingham said.

"The management team will meet again Thursday afternoon to confirm the earliest practical launch date based on the most recent engineering assessments."

Engineers are looking to find the source of the problem, which will determine if the fix will be straightforward and permit launch Friday or something more significant requiring a longer postponement to correct.

0158 GMT (8:58 p.m. EST Wed.)

DELAYED FURTHER. Officials have determined a launch attempt is not possible on Thursday as engineers continue to work through the Range safety system problem. Launch could occur as early as Friday. Details to follow.

WEDNESDAY, NOVEMBER 17, 2004
1925 GMT (2:25 p.m. EST)

A NASA spokeswoman says a decision whether Swift can launch tomorrow won't be made until late tonight. An announcement is expected around 9 p.m. EST (0200 GMT).

1507 GMT (10:07 a.m. EST)

NASA says this Range safety system problem involves the Command Receiver Decoder equipment on the Delta vehicle. The concern arose after the "safe and arm" devices were connected on the launch vehicle. The system would be used to destruct the rocket during launch in the event of a major problem.

"The decision to postpone the launch occurred as engineers were making final checks prior to launch tower roll back at Complex 17 on Cape Canaveral Air Force Station in Florida," the space agency said in a statement issued a short time ago.

"The management team will meet later today to confirm the launch date based on the latest engineering assessments which are on going today."

We'll update this page as additional information becomes available.

1258 GMT (7:58 a.m. EST)

The launch of Swift could be rescheduled for Thursday at the earliest, NASA says, if a glitch with the Delta 2 rocket's safety system can be resolved quickly.

"An issue occurred overnight regarding the Range safety system aboard the vehicle. Managers will be meeting later this morning to determine the extent of the need to either replace or repair that electronic system," NASA spokesman Bruce Buckingham said.

All rockets launched from Cape Canaveral are equipped with the safety system that allows the Range to destroy the booster if it veers off course or experiences a malfunction during ascent. The system is meant to protect the public.

1215 GMT (7:15 a.m. EST)

DELAY. Today's launch was scrubbed overnight due to a technical problem, Boeing says. Mission managers will meet later today to review the issue and determine how long this delay will last. It was not immediately announced what the problem involved.

The mobile service tower remains around the rocket at launch pad 17A.

If the launch is rescheduled for Thursday, the weather forecast calls for better than a 90 percent chance of favorable conditions.

TUESDAY, NOVEMBER 16, 2004

NASA's Swift gamma-ray observatory is ready to rocket into space Wednesday to begin a two-year mission of detecting the most intense explosions in the universe. Liftoff is scheduled for 12:09 p.m. EST (1709 GMT), the opening of a 60-minute launch opportunity.

"We are not working any issues," NASA launch manager Chuck Dovale told reporters during the pre-launch news conference Tuesday afternoon.

The mobile service tower enclosing the Boeing Delta 2 rocket at Cape Canaveral's pad 17A will be retracted after 1 a.m. EST (0600 GMT), exposing the 126-foot vehicle to bright floodlights in the Florida nighttime darkness.

Workers will get the tower locked into its launch position and put the final touches on rocket and ground equipment before evacuating the pad by about 9 a.m. EST (1400 GMT).

The Terminal Countdown commences at 9:29 a.m. EST (1429 GMT) for the final two hours and 40 minutes to launch. That is 20 minutes shorter than usual because officials have deleted the typical built-in hold at the T-minus 20 minute mark. Officials schedule hold periods to give engineers time to work problems or catch up on late-running activities. But with Wednesday's hour-long launch window, it was decided the T-minus 20 minute hold wasn't necessary.

The launch team will start loading a highly refined kerosene propellant into the rocket's first stage at 9:49 a.m. EST (1449 GMT). Filling of the first stage liquid oxygen tank will follow beginning at 10:44 a.m. EST (1544 GMT).

The final hour of the countdown will be spent conducting engine steering tests, Range Safety checks and final arming. Swift switches to internal power for launch about six minutes before liftoff time, while the Delta rocket's systems transition to battery power inside the final four minutes.

The count will feature one built-in hold at T-minus 4 minutes lasting for 10 minutes. During that time, mission managers will conduct a series of readiness polls to ensure everyone is "go" to proceed with liftoff.

Weather officials continue to predict a 90 percent chance of acceptable conditions during the launch window.

"After Charley, Frances, Jeanne, one tornado and several days of high winds, I'm happy to say I don't expect any weather problems for tonight and through the next days," Joel Tumbiolo, the Air Force launch weather officer, said Tuesday.

A backup launch opportunity is available Thursday, if needed. The weather forecast calls for perfect conditions.

1903 GMT (2:03 p.m. EST)

The Launch Readiness Review has been completed today and all systems are reported "go" for tomorrow's launch of the Delta 2 rocket carrying the Swift gamma-ray observatory into space.

"NASA, Swift, Boeing, the Air Force and Range are all ready to proceed," NASA launch manager Chuck Dovale says.

1700 GMT (12:00 p.m. EST)

Air Force meteorologists have improve the outlook for tomorrow's launch of NASA's Swift observatory aboard the Boeing Delta 2 rocket. There is now a 90 percent chance of acceptable weather conditions. You can read the full forecast here.

MONDAY, NOVEMBER 15, 2004

Launch of Swift remains on schedule for Wednesday. The weather forecast continues to indicate an 80 percent chance of acceptable conditions during the available launch window extending from 12:09 to 1:09 p.m. EST.

Mission managers will gather for the Launch Readiness Review on Tuesday. That will be followed by the pre-launch news conference. We'll post a complete countdown preview later in the day.

SUNDAY, NOVEMBER 14, 2004

An agile gamma-ray observatory with a focus on the most intense explosions in the cosmos -- cataclysmic blasts occurring every day throughout the universe that seemingly foreshadow the creation of black holes -- will be launched into space Wednesday from Cape Canaveral, Florida.

While circling Earth at an altitude of 375 miles, NASA's Swift spacecraft will detect and study the brilliant bursts of gamma-rays, which erupt in random points across the sky without warning. Swift's scientific data will determine a burst's distance and brightness, plus provide insight into the blast's locale and surroundings to offer clues about what ignites these events.

"Gamma-ray bursts have ranked among the biggest mysteries in astronomy since their discovery over 35 years ago," said Neil Gehrels, Swift lead scientist from NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Gamma-ray bursts last between a few milliseconds and a few minutes and never appear in the same spot again. They emit more than one hundred billion times the energy than the Sun does in an entire year. A lingering afterglow -- a phenomenon discovered just seven years ago -- can last hours or weeks in X-ray and optical light and radio waves, but strangely not all bursts have an afterglow.

Astrophysicists have two competing ideas to explain the origin of gamma-ray bursts and both are linked to black holes. The death of massive stars in extraordinary explosions, called hypernovae, that result in the birth of black holes and two neutron stars orbiting each other that eventually collide and create a black hole are scenarios that would produce such violent releases of gamma-rays.

Project leaders hope the $239 million mission will explain why some bursts are significantly shorter than others, why some lack an afterglow and answer the fundamental question of what triggers a burst. Swift could discover there are different types of gamma-ray bursts, proving more than one of the theories put forth by astronomers.

"Swift is just the right tool needed to solve this mystery. One of Swift's instruments will detect the burst, while, within a minute, two higher-resolution telescopes will be swung around for an in-depth look. Meanwhile, Swift will 'e-mail' scientists and telescopes around the world to observe the burst in real-time," Gehrels said.

The Swift spacecraft gets its name from the nimble bird because the satellite can swiftly turn to catch a burst and afterglow on the fly.

The observatory's Burst Alert Telescope, which can see a sixth of the entire sky at one time, will detect and locate the flashes. That positioning information allows the satellite to reorient itself within moments to point the onboard X-ray Telescope and the Ultraviolet/Optical Telescope to conduct a thorough examination of the afterglow, perhaps even the burst itself if the blast lasts long enough.

"Swift is an awe-inspiring mission -- tracking down what are the fastest and most powerful events in the universe," said professor Alan Wells from the University of Leicester, the U.K. lead investigator for Swift's X-ray telescope.

"These telescopes will provide unique information on these bursts to help us unravel what is going on in these amazing cosmological events."

Some bursts may occur in the first generation of stars, scientists believe, and Swift should either prove or squash this theory. By peering billions of years into the past, Swift's research will help study the early universe, too, and potentially offer clues to the rate of black hole creation.

"Some bursts likely originate from the farthest reaches, and hence earliest epoch, of the universe," said Swift mission director John Nousek, professor of astronomy and astrophysics at Penn State. "They act like beacons shining through everything along their paths, including the gas between and within galaxies along the line of sight."

The two-year mission aims to observe more than 200 bursts. The Swift spacecraft -- one of the largest, most sophisticated satellites in NASA's long line of Explorer missions -- includes partners in the U.K. and Italy.

The Burst Alert Telescope was built by NASA's Goddard Space Flight Center; the X-ray Telescope was made by Penn State University, the University of Leicester and Italy's Osservatorio Astronomico di Brera; and the Ultraviolet/Optical Telescope was built by Penn State and the U.K.'s Mullard Space Science Laboratory. Spectrum Astro built Swift's structure.

A two-stage Boeing-built Delta 2 rocket is to loft Swift from Cape Canaveral's pad 17A on Wednesday during a one-hour launch window extending from 12:09 to 1:09 p.m. EST (1709-1809 GMT). The launch was delayed from October by Florida's seemingly magnetic attraction to hurricanes this year and a longer-than-expected wait for another Delta 2 rocket to fly from the neighboring pad 17B carrying a GPS military navigation satellite.

The rocket will haul the 3,417-pound Swift into a circular orbit 373 miles above Earth with an inclination no greater than 22 degrees north and south of the equator.

About 80 minutes after liftoff, the pyrotechnic bolts holding the satellite to the second stage motor will fire and release. Thirty seconds later, latches pop open to physically separate Swift from its launcher. The rocket stage slowly backs away from its payload, leaving the observatory in a stable state, said Mark Edison, the Swift program manager at satellite-builder Spectrum Astro.

A forward-facing video camera mounted on the second stage is expected to provide live coverage of Swift's deployment from the Delta rocket.

Just minutes after separation, Swift automatically switches on its control system and deploys the two power-generating solar arrays that spring upward from stowed positions on the satellite's sides and then unfold.

Over the next 30 days, the satellite systems are checked out via the mission control center located at Penn State University, Edison said.

The science instruments are activated and data begins flowing after the first month. The science commissioning phase could last through the mission's initial four months.

"We expect to be fully operational by Launch + 4 months," Gehrels said.

Swift is designed to operate two years, but Joseph Dezio, the mission project manager at NASA's Goddard Space Flight Center, says a five-year life is possible.

Because the satellite has no steering thrusters or onboard propellant, the two key consumables dictating the mission duration will be Swift's battery and funding by NASA.

The first stage of Boeing's Delta 2 rocket to launch Swift was erected on pad 17A October 1, following delays caused by the hurricanes and closure of Cape Canaveral Air Force Station.

The three strap-on solid rocket boosters were added October 2. Given Swift's relatively light weight and orbit requirements, the Delta 2 will use three solids instead of the usual nine.

The two halves of the 10-foot diameter payload fairing nose cone were lifted into pad's mobile service tower cleanroom for storage on October 4.

Mounting of the second stage atop the Delta rocket's first stage occurred October 8.

Final work on Swift was finished in the Hangar AE cleanroom, allowing the craft to be packaged in the transport canister and driven a few miles to pad 17A. It was mated to the Delta rocket on November 8. Installation of the rocket's nose cone around the satellite occurred Friday.

The Flight Readiness Review was held by senior managers Saturday. The loading of storable propellant and oxidizer into the rocket's second stage is planned for Monday. The Launch Readiness Review to give approval to start the countdown will happen Tuesday.

We will provide live coverage of the countdown and launch on this page!

SATURDAY, NOVEMBER 13, 2004

Today's version of the launch weather forecast removes the concern for rain in the rocket's flight path. Ground winds and thick cloud cover are the two worries for Wednesday's hour-long launch window. See the full forecast here.

FRIDAY, NOVEMBER 12, 2004

The early weather forecast for Wednesday's launch opportunity calls for an 80 percent chance of acceptable conditions. Gusty launch pad winds, thick clouds and rain in the rocket's flight path are all potential concerns. See the full forecast here.