BY JUSTIN RAY

Follow the countdown and launch of the Orbital Sciences Minotaur rocket with the U.S. military's STP-R1 "Streak" technology demonstration satellite. Reload this page for the very latest on the mission.

FRIDAY, SEPTEMBER 23, 2005

A grand spectacle in the evening sky created by a spacebound rocket delighted stargazers and frightened the uninformed across hundreds of miles in the southwestern United States on Thursday. Read our full story.

0427 GMT (9:27 p.m. PDT Thurs.)

The Streak satellite's operator -- the Defense Advanced Research Projects Agency -- says the spacecraft was deployed from the Minotaur fourth stage.

0240 GMT (7:40 p.m. PDT Thurs.)

T+plus 16 minutes. No confirmation of spacecraft deployment from the rocket has been announced. We'll be awaiting additional information from launch officials to determine if Minotaur has successfully completed its mission this evening.

0235 GMT (7:35 p.m. PDT Thurs.)

T+plus 11 minutes. Standing by for further word.

0232 GMT (7:32 p.m. PDT Thurs.)

T+plus 7 minutes, 50 seconds. Thrust has tailed off from the solid-fueled fourth stage to complete the burn.

0231 GMT (7:31 p.m. PDT Thurs.)

T+plus 7 minutes, 15 seconds. All systems appear normal as fourth stage continues to burn.

0230 GMT (7:30 p.m. PDT Thurs.)

T+plus 6 minutes, 30 seconds. Fourth stage stage ignition!

0229 GMT (7:29 p.m. PDT Thurs.)

T+plus 6 minutes, 28 seconds. The third stage has been jettisoned from the fourth stage. Coming up on ignition of the fourth stage.

0229 GMT (7:29 p.m. PDT Thurs.)

T+plus 5 minutes. Minotaur remains in the ballistic coast phase of flight. The spent third stage will be shed, followed by fourth stage ignition in approximately 90 seconds from now.

0228 GMT (7:28 p.m. PDT Thurs.)

T+plus 4 minutes. Performance so far in this launch indicates the target apogee altitude high point will be reached.

0228 GMT (7:28 p.m. PDT Thurs.)

T+plus 3 minutes, 35 seconds. The solid-fuel third stage has burned out, and the rocket is now in a brief coast period.

0227 GMT (7:27 p.m. PDT Thurs.)

T+plus 3 minutes, 15 seconds. All appears normal with the flight as the third stage solid motor continues to fire.

0227 GMT (7:27 p.m. PDT Thurs.)

T+plus 2 minutes, 45 seconds. The rocket's payload fairing nose cone has separated.

0226 GMT (7:26 p.m. PDT Thurs.)

T+plus 2 minutes, 19 seconds. Third stage ignition confirmed as the spent second stage falls way. This sheds the Minuteman 2 portion of Minotaur and the Pegasus heritage solid-fuel motors take over.

0225 GMT (7:25 p.m. PDT Thurs.)

T+plus 80 seconds. Second stage is burning well.

0225 GMT (7:25 p.m. PDT Thurs.)

T+plus 67 seconds. Staging has occurred. The first and second stages separated. And the second stage motor has ignited.

0225 GMT (7:25 p.m. PDT Thurs.)

T+plus 45 seconds. The rocket's orientation remains normal as it passes through the region of maximum aerodynamic pressures of ascent.

0224 GMT (7:24 p.m. PDT Thurs.)

T+plus 25 seconds. A good flight of Minotaur is being reported from the vehicle telemetry receiving sites.

0224 GMT (7:24 p.m. PDT Thurs.)

T+plus 10 seconds. First stage motor pressure nominal.

0224:29 GMT (7:24:29 p.m. PDT Thurs.)

LIFTOFF! Liftoff of the Minotaur rocket with the Streak satellite, launching a new Space Test Program research mission for the U.S. military.

0223:59 GMT (7:23:59 p.m. PDT Thurs.)

T-minus 30 seconds.

0223:29 GMT (7:23:29 p.m. PDT Thurs.)

T-minus 1 minute. Data recording charts are running.

0222 GMT (7:22 p.m. PDT Thurs.)

T-minus 100 seconds. The rocket ordnance has been armed.

0222 GMT (7:22 p.m. PDT Thurs.)

T-minus 2 minutes. Auto sequence start. Flight computer is controlling the countdown.

0221 GMT (7:21 p.m. PDT Thurs.)

T-minus 2 minutes, 30 seconds. Coming up on auto sequence start in 30 seconds.

0221 GMT (7:21 p.m. PDT Thurs.)

T-minus 3 minutes. The Air Force-controlled Western Range is clear for launch.

0220 GMT (7:20 p.m. PDT Thurs.)

T-minus 3 minutes, 40 seconds. The air conditioning duct to the rocket's payload fairing nose cone has been retracted.

0220 GMT (7:20 p.m. PDT Thurs.)

T-minus 4 minutes. The flight computer is armed. And the C-band tracking beacon is functioning as expected on interal power.

0219 GMT (7:19 p.m. PDT Thurs.)

T-minus 5 minutes. The rocket's avionics are switching to internal power.

0218 GMT (7:18 p.m. PDT Thurs.)

T-minus 6 minutes. The final management poll ended with concurrence to launch right on time. There are no problems standing in the way of liftoff.

0217 GMT (7:17 p.m. PDT Thurs.)

T-minus 6 minutes, 45 seconds. The Space Test Program-R1's Streak satellite has been declared "go" for launch.

0217 GMT (7:17 p.m. PDT Thurs.)

T-minus 7 minutes. Coming up on the last pre-launch poll of the mission management team.

0216 GMT (7:16 p.m. PDT Thurs.)

T-minus 8 minutes and counting.

0215 GMT (7:15 p.m. PDT Thurs.)

T-minus 8 minutes, 35 seconds. The flight termination system is now armed.

0215 GMT (7:15 p.m. PDT Thurs.)

T-minus 9 minutes. The rocket's flight termination system has switched to interal power. The FTS would be used to destroy the rocket should a problem arise during flight.

0214 GMT (7:14 p.m. PDT Thurs.)

T-minus 10 minutes and counting.

0213 GMT (7:13 p.m. PDT Thurs.)

T-minus 11 minutes. The guidance computer's voltages and currents are reported normal.

0212 GMT (7:12 p.m. PDT Thurs.)

T-minus 12 minutes. The exact 0224:29 GMT (7:24:29 p.m. local) launch time is being loaded into the rocket's flight computer.

0211 GMT (7:11 p.m. PDT Thurs.)

T-minus 13 minutes. Removal of the thermal blanket covering the Minotaur rocket's Minuteman stages has been completed. This cover is affectionately called the "banana" because of its color and since it's peeled away in sections.

0210 GMT (7:10 p.m. PDT Thurs.)

T-minus 14 minutes. Safety officials confirm that the hazard area and impact zones are clear for launch.

0209 GMT (7:09 p.m. PDT Thurs.)

T-minus 15 minutes. The final launch readiness poll of various team members was just conducted. All systems remain "go" for liftoff of the Minotaur rocket and the Streak spacecraft from Vandenberg Air Force Base, Calif.

The approval has been given to start removing the thermal blanket covering the bottom half of the rocket. This operation is being performed remotely without workers at the pad via an automatic retraction system.

0206 GMT (7:06 p.m. PDT Thurs.)

Minotaur's precise target launch time is 0224:29 GMT (7:24:29 p.m. local).

0205 GMT (7:05 p.m. PDT Thurs.)

T-minus 19 minutes. Ground and high-altitude winds are acceptable for launch.

0204 GMT (7:04 p.m. PDT Thurs.)

Tension is building as the countdown enters the final 20 minutes to launch.

0159 GMT (6:59 p.m. PDT Thurs.)

T-minus 25 minutes. A safety test of the rocket's flight termination system is starting. This system would be activated to destroy Minotaur if the rocket veered off course or experienced a major problem during launch.

0154 GMT (6:54 p.m. PDT Thurs.)

T-minus 30 minutes. The rocket's tracking beacon is being verified by the Western Range.

0149 GMT (6:49 p.m. PDT Thurs.)

Now passing the T-minus 35 minute mark in the countdown. The launch team is not reporting any technical problems.

0144 GMT (6:44 p.m. PDT Thurs.)

T-minus 40 minutes and counting. Voltage and current readings from the rocket have been verified normal by the launch team.

0141 GMT (6:41 p.m. PDT Thurs.)

The launch pad danger area has been confirmed clear of all personnel.

0135 GMT (6:35 p.m. PDT Thurs.)

Minotaur's guidance system is in alignment.

0128 GMT (6:28 p.m. PDT Thurs.)

The S-band data communications link check has been completed.

0125 GMT (6:25 p.m. PDT Thurs.)

The rocket's avionics are being powered to permit the inertial guidance system final pre-launch alignment and test the S-band communications antenna signal strength.

0124 GMT (6:24 p.m. PDT Thurs.)

T-minus 60 minutes and counting. No problems are being reported with the Minotaur rocket as clocks continue to tick down for launch.

The launch team is opening up the final checklist to guide activities through liftoff.

0110 GMT (6:10 p.m. PDT Thurs.)

The countdown quietly rolls on at Vandenberg. Viewing the liftoff from the launch site could be hampered by low fog and high clouds tonight.

0056 GMT (5:56 p.m. PDT Thurs.)

The arming and final closeouts checklist has been completed now that the launch support equipment is powered up again. Technicians plan to begin using the final launch checklist at the T-minus 1 hour mark.

0054 GMT (5:54 p.m. PDT Thurs.)

T-minus 90 minutes.

0044 GMT (5:44 p.m. PDT Thurs.)

The Streak satellite payload atop the Minotaur rocket has been powered and readied to proceed with this evening's launch operation.

0035 GMT (5:35 p.m. PDT Thurs.)

Hands-on work at the launch pad has been finished. Crews are now departing Space Launch Complex 8 in preparation for liftoff.

0024 GMT (5:24 p.m. PDT Thurs.)

T-minus 2 hours and counting down to this evening's launch of the Minotaur rocket carrying an experimental military research satellite from Vandenberg Air Force Base, California.

0017 GMT (5:17 p.m. PDT Thurs.)

Approval has been given for arming and final closeouts of the Minotaur rocket.

0010 GMT (5:10 p.m. PDT Thurs.)

The pre-launch checkout of rocket systems has wrapped up, allowing support equipment to be powered down.

0002 GMT (5:02 p.m. PDT Thurs.)

Interrogation checks of the Minotaur's C-band beacon used for tracking the rocket during launch have been completed.

2354 GMT (4:54 p.m. PDT)

T-minus 2 hours, 30 minutes and counting. The pre-flight alignment of the rocket's inertial navigation system has been completed. Meanwhile, a steering test of Minotaur first stage engine nozzles is upcoming.

2351 GMT (4:51 p.m. PDT)

The mobile launch pad tower is back at the launch location again.

2348 GMT (4:48 p.m. PDT)

Initialization of the rocket's guidance computer brain is underway.

2343 GMT (4:43 p.m. PDT)

The air conditioning duct has been successfully refitted to the Minotaur rocket's white nose cone. The hose had loosened in the windy conditions at the launch pad.

Crews are returning the service tower to its retracted parking spot for launch so that countdown activities can resume.

2330 GMT (4:30 p.m. PDT)

The tower is around the Minotaur vehicle and technicians are working to reconnect the air duct to the rocket payload fairing.

2317 GMT (4:17 p.m. PDT)

The hose-like duct that feeds conditioned air into the rocket's nose cone has become partially disconnected in the high winds blowing across the launch pad this afternoon. The mobile shelter is going to be rolled back around the rocket to give workers access to the duct for reattachment. Once the quick fix is completed, the tower will be returned to its launch location.

2305 GMT (4:05 p.m. PDT)

Link checks between the rocket's flight termination system and one of the backup Range Safety sites have been underway.

2250 GMT (3:50 p.m. PDT)

Telemetry data links with ground-receiving sites are being tested.

2240 GMT (3:40 p.m. PDT)

The mobile shelter that has enclosed the Minotaur rocket on the launch pad just completed its rollback for liftoff. This tower-like structure now stands secured in its launch position away from the rocket.

2226 GMT (3:26 p.m. PDT)

Retraction of the launch pad service structure from around the rocket is beginning.

2224 GMT (3:24 p.m. PDT)

T-minus 4 hours and counting.

2200 GMT (3:00 p.m. PDT)

The Streak satellite is reported in good shape. Meanwhile, initial checks of the rocket's flight computer have been completed.

2140 GMT (2:40 p.m. PDT)

Launch day activities are proceeding at the Minotaur's pad on the south end of Vandenberg. The danger area around the base of the rocket has been cleared of all personnel for the start of hazardous operations in the countdown.

The launch support equipment was turned on a short time ago, then the rocket was powered up in preparation for pre-flight system testing.

2124 GMT (2:24 p.m. PDT)

The launch countdown has begun for this evening's liftoff of the Minotaur rocket and STP-R1 mission from California's central coast. The launch team is proceeding through the countdown checklist to ready systems and the vehicle for blastoff, which remains scheduled to occur five hours from now.

THURSDAY, SEPTEMBER 22, 2005

When the sun goes down at California's Vandenberg Air Force Base tonight, an obscure little satellite will blast off to begin its year-long mission for the U.S. military's research and development agency.

The Space Test Program-R1 project's Streak satellite carries a classified price tag and limited details about its underlying purpose. But the launch should be widely visible throughout central and southern California, perhaps as far inland as Arizona and Nevada, if weather conditions permit, when the Minotaur rocket roars into space to deploy its cargo.

Liftoff from the Space Launch Complex 8 pad located on Vandenberg's southern edge will occur during a window extending from 7:24 to 7:40 p.m. PDT (10:24-10:40 p.m. EDT; 0224-0240 GMT). The period opens nearly a half-hour after sunset.

Ascending skyward along a southerly trajectory over the Pacific, the slender white rocket has the potential to produce a spectacular "twilight phenomenon" display of green, blue, white and rose colors in expanding, twisting clouds. The cause: unburned fuel particles and water drops in the rocket's contrail freeze in the less dense upper atmosphere and get reflected by sunlight at high altitudes during launches timed just before sunrise or shortly after sunset.

The Orbital Sciences-managed Minotaur rocket is formed by using decommissioned first and second stages from a Minuteman 2 ICBM missile and solid-propellant motors from the commercial Pegasus rocket program for its third and fourth stages. The vehicle is designed to provide the U.S. government with reliable access to space for small satellites.

This will be the second Minotaur launch of the year and fourth since 2000. All have been successful so far.

Air Force launch officials say it will take about nine minutes for the Minotaur to haul the STP-R1 mission to the desired orbit tonight. The satellite, dubbed Streak by its operator, will test technologies for the Defense Advanced Research Projects Agency.

"Streak is a technology demonstrator whose objective is to demonstrate rapid response, short mission life, low Earth orbit space technologies and gather information about the low Earth orbit environment," a DARPA spokesperson said.

Information released by DARPA indicates Streak is fitted with two instruments -- an ion gauge and an atomic oxygen sensor.

"The vehicle will characterize the orbital regime, demonstrate operational feasibility from a command and control standpoint and also from a platform perspective for future DoD missions," the spokesperson added.

General Dynamics C4 Systems/Spectrum Astro Space Systems built the craft in Gilbert, Arizona.

DARPA is the Defense Department organization whose mission is "to maintain the technological superiority of the U.S. military and prevent technological surprise from harming our national security by sponsoring revolutionary, high-payoff research that bridges the gap between fundamental discoveries and their military use."

Tonight's weather forecast predicts an 80 percent chance of acceptable conditions for launch. Thick clouds are the only concern for violating the launch rules.

"A weak high pressure ridge moves east Thursday afternoon, while a shallow marine layer comes ashore. An upper level trough drops into the area with altocumulus and thick cirrus over Vandenberg, while low ceilings and dense fog obscure visibility," the launch weather officer reported Wednesday.

The "marine layer" of low stratus clouds will cover the entire sky over the launch pad between 400 and 1,200 feet. Mid- and high-level clouds are expected at 15,000 and 23,000 feet. Forecasters also predict fog to reduce visibility to one mile, with a temperature between 64 and 69 degrees, ground winds of 13-to-18 knots from the northwest and maximum high-altitude winds of 44 knots near 40,000 feet.

Should the launch be delayed to Friday evening for some reason, the outlook calls for a 100 percent probability of acceptable liftoff conditions. But the viewing situation at Vandenberg is likely to remain foggy.

"An upper level low and associated trough moves into the Pacific northwest. The marine layer returns, thickening and lifting as the trough moves closer and destabilizes the atmosphere. Visibility improves to 3 miles. The gradient between the exiting ridge and this trough tightens with surface winds out of the northwest at 15 - 20 knots. Upper level winds remain northwesterly."

Watch this page for live updates during this evening's countdown and launch!