A trailblazing payload for the National Reconnaissance Office successfully rocketed into orbit on a Minotaur 1 booster Sunday, beginning a secret mission testing new ways to collect intelligence from space.

The mission was codenamed NROL-66 in the agency's rocket acquisition naming system. The payload is also called RPP, which is short for Rapid Pathfinder Program.

"I commend everyone who made this launch successful," said Robert Brodowski, director of the NRO's advanced science and technology directorate. "This mission is just one example of our ability to rapidly build and launch small spacecraft with on-orbit capabilities that increase the value of NRO systems to our nation's future."

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And see the launch photo gallery from sound-activated cameras at the pad.

This was the National Reconnaissance Office's fourth satellite launch since September, a remarkable surge of missions that continues with two more flights planned in the next two months. The series began and will end with clandestine Atlas 5 flights from Vandenberg.

• An Atlas 5-501 on the NROL-41 mission launched from Vandenberg on Sept. 20
• A Delta 4-Heavy rocket for NROL-32 launched from Cape Canaveral on Nov. 21
• A Delta 4-Heavy rocket for NROL-49 launched from Vandenberg on Jan. 20
• Today's Minotaur 1 rocket on NROL-66
• Next up is the Delta 4-Medium+4,2 rocket for NROL-27 from Cape Canaveral on March 11
• And an Atlas 5-411 for NROL-34 is planned from Vandenberg on April 12

"This is the most aggressive launch campaign we've had in 20 years," NRO Director Bruce Carlson was quoted as saying at the Air Force Association conference last year.

Here's a quote from Vandenberg's post-launch press release:

"I am extremely proud of the large group of professionals that came together to launch this rocket. The 30th Space Wing and its mission partners have a long history of successful Minotaur launches and we are proud to continue that history again here today," said Col. Richard Boltz, 30th Space Wing commander and the launch decision authority.

Here's two great streak shots of the Minotaur rocket's blastoff this morning taken by Gene Blevins at Harris Grade in Lompoc.

Based on a normal Minotaur 1 ascent, the Orion 50XL third stage motor performs its burn immediately after the second stage falls away. That sheds the Minuteman 2 portion of Minotaur and the heritage solid-fuel motors from the commercial Pegasus took over.

Minotaur flies a ballistic coast phase of flight after the third stage burns out. The spent stage holds on while the rocket soars to the orbit's high point, then separates when the fourth stage ignites to deliver the final boost to enter the intended perch above the planet.

As is customary with National Reconnaissance Office launches, no further live updates will be available on the rocket's progress toward orbit or release of the satellite cargo. At the time of the news blackout, Minotaur appeared to be performing normally at the end of its second stage burn.

T+plus 2 minutes. Minotaur is heading southward over the Pacific with systems operating in good shape.

T+plus 100 seconds. Flight path and orientation of the vehicle are nominal.

T+plus 80 seconds. Rocket is flying normally as the second stage SR19 motor fires.

T+plus 66 seconds. The first staging event has occurred. The first stage M55A1 solid rocket motor has jettisoned and the second stage motor ignited.

T+plus 38 seconds. The rocket's is passing through the region of maximum aerodynamic pressures of ascent.

T+plus 16 seconds. First stage motor pressure is nominal as the six-story booster soars into the predawn sky.

LIFTOFF! Liftoff of the Minotaur 1 rocket launching the NROL-66 mission for the Rapid Pathfinder Program.

T-minus 30 seconds to launch.

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

T-minus 75 seconds and counting.

T-minus 90 seconds. The rocket ordnance has been armed.

T-minus 2 minutes. Auto sequence start. Minotaur's flight computer is controlling the countdown.

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

T-minus 3 minutes. The Range is clear for launch.

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

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

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

T-minus 6 minutes. The final round of management polls concluded with the authority to launch right on-time this morning.

T-minus 7 minutes and counting.

T-minus 8 minutes. The safety system is now armed.

T-minus 9 minutes. The rocket's flight safety system has switched to internal power.

T-minus 9 minutes, 30 seconds. The guidance computer's voltages and currents are reported normal.

T-minus 10 minutes and counting.

T-minus 12 minutes. The exact 1226:00 GMT (4:26:00 a.m. PST) launch time is being loaded into the rocket's flight computer.

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

T-minus 15 minutes. The launch readiness poll of various team members just occurred. All systems are "go" for liftoff of the Minotaur rocket and the NROL-66 mission from Vandenberg Air Force Base, Calif.

Launch team members will be polled in the next few minutes to confirm everything is ready for liftoff.

T-minus 19 minutes. High-altitude winds are acceptable for launch.

T-minus 20 minutes and counting. Minotaur's target launch time remains 4:26:00 a.m. local.

Now passing the T-minus 25 minute mark in the countdown.

T-minus 27 minutes. A safety test of the rocket's flight termination system is underway.

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

T-minus 35 minutes. The earlier ground problem has been resolved. So all elements are reporting "go" status at the present time.

T-minus 37 minutes. Voltage and current readings from the rocket on external power are verified as normal by the launch team.

T-minus 40 minutes and counting. The launch pad danger area has been confirmed clear of all personnel.

Minotaur's guidance system is in alignment for today's climb to orbit.

The S-band data communications link tests are complete.

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

T-minus 60 minutes and counting. The launch team is opening up the final checklist to guide activities through liftoff.

Officials expect the ground problem currently being worked will be resolved in the next half-hour or so. Clocks continue to tick down for launch at 4:26 a.m. local.

As the countdown proceeds toward launch this morning, you can follow along right here on this page.

But if you will be away from your computer, sign up for our Twitter feed and get text message updates on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

Just 75 minutes remain in the countdown to launch of the Minotaur 1 rocket. The Orbital Sciences-managed rocket uses decommissioned first and second stages from Minuteman 2 intercontinental ballistic missiles and solid-propellant motors from the commercial Pegasus rocket program for its third and fourth stages. The vehicle was created to launch small satellites.

Minotaur 1 has flown eight times since 2000, successfully placing 30 spacecraft into orbit. Five missions originated from Vandenberg and three flew from Wallops Island, Virginia.

Today's launch will be the first flight with the National Reconnaissance Office as the customer.

This is the quiet period in the countdown. Technicians will begin marching through the final launch checklist starting at T-minus 1 hour.

Now 100 minutes from the scheduled launch time. All systems on the Minotaur are "green" with no issues being reported on the vehicle. However, there is another ground issue being assessed right now.

The launch support equipment is being powered up again.

Hands-on work at the launch pad has been finished. Crews are now departing Space Launch Complex 8 in preparation for this morning's predawn liftoff of the Minotaur 1 booster.

Arming, closeouts and launch site preps are complete at the Minotaur's pad on the south end of Vandenberg.

T-minus 2 hours. The Orbital launch conductor has given the "go" to proceed with the final pad work.

T-minus 2 hours, 15 minutes and counting down to today's launch of the Minotaur 1 rocket carrying a technology demonstration payload for U.S. national security satellites from Vandenberg Air Force Base, California.

T-minus 2 hours, 26 minutes. The pad crew is prepared for arming and final closeouts of the Minotaur rocket.

If you will be away from your computer but would like to receive occasional countdown updates, sign up for our Twitter feed to get text message updates on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

T-minus 3 hours and counting. Everything continues to look good.

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

Simulated liftoff testing is occurring to ensure that receiving stations will be able to detect the signal announcing Minotaur's launch.

Minotaur's C-band beacon used for tracking the rocket during launch have been tested.

And the second stage steering test has been accomplished.

First stage engine steering sequence test is complete. Moving to the second stage now.

The pre-flight alignment of the rocket's inertial navigation system has been verified complete. A steering test of the Minotaur engine nozzles is coming up.

The Minotaur's main computer is initialized for the pre-flight guidance alignment.

The rocket S-band transponder interrogation tests and link checks to the vehicle's flight safety system have been run.

Minotaur is ready to be powered up in preparation for upcoming pre-flight system testing.

No problems are being reported in this morning's countdown and launch remains on schedule for 4:26 a.m.

T-minus 4 hours and counting.

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 in its launch position away from the rocket.

"SLC-8 is austere but still a very effective system," Lt. Col. Timothy Harris, commander of the 1st Air and Space Test Squadron, said in an interview Thursday. "We have a tug, or forklift, that's attached to the mobile service tower. We fire that up and are able to tow the tower back and out of the way."

Approval has been given to launch pad technicians for rollback of the service structure from around the rocket.

The gantry that has shrouded the Minotaur at Space Launch Complex 8 will slowly roll away from the six-story booster in preparation for today's 4:26 a.m. PST blastoff. The mobile tower provided workers access to the various parts of the rocket and gave the vehicle shelter from the weather during the pre-launch mission campaign.

T-minus 5 hours and counting! A second launch attempt has begun for the Minotaur 1 rocket on the NROL-66 mission for the National Reconnaissance Office.

Following Saturday morning's scrub, the launch team safed the booster and backed out of the countdown sequence. Another shot at liftoff starts now with the team re-entering into the countdown checklists to ready systems for blastoff at 4:26 a.m. local time from California's central coast.

In a post-scrub press release this morning, the Air Force provided further details about the power problem with a piece of critical ground equipment:

"During the countdown, Western Range controllers observed a power fluctuation on a transmitter used to maintain positive control over the launch vehicle throughout range operations," the statement said.

"Safety is our number one priority, so we are analyzing the situation and taking every necessary precaution," said Col. Richard Boltz, 30th Space Wing commander and launch decision authority.

Launch is rescheduled for Sunday at 4:26 a.m. PST (7:26 a.m. EST; 1226 GMT), pending resolution of the power issue.

Weather forecasters are predicting another day of good conditions for a launch attempt on Sunday morning. The outlook calls for just a few high clouds at 30,000 feet, good visibility, easterly winds of 12 to 18 knots and a temperature in the low 50s F.

To recap, liftoff of the Minotaur rocket was scheduled for 4:26 a.m. PST today and countdown activities were proceeding smoothly throughout the early morning hours. But a mandatory ground support asset developed a problem and the clocks were forced to stop at T-minus 16 minutes.

After monitoring the progress of troubleshooting efforts, officials reset launch for 6:12 a.m. PST and restarted a recycled countdown from the T-minus 60 minute mark.

But at about T-minus 37 minutes, the countdown was halted again because of the on-going problem. Technicians determined the glitch could not be fixed in time for a launch this morning.

The launch vehicle is being safed for this 24-hour postponement. The preliminary game plan calls for another countdown on Sunday morning for liftoff of the Minotaur 1 rocket from Vandenberg Air Force Base, California.

The launch team will prepare for another countdown and liftoff attempt on Sunday morning.

The Minotaur rocket is being powered down and soon the launch pad will be reopened for workers to return.

HOLD. Countdown has been stopped again. The problem can't be resolved in time for a launch today, so the Minotaur will not fly this morning.

T-minus 40 minutes and counting to the new launch time of 6:12 a.m. PST.

Weather remains "go" and the rocket has no issues. But still awaiting confirmation that the ground problem is fixed.

The rocket's inertial guidance system is going through another pre-launch alignment.

Checks have been taken of the S-band telemetry communications antenna signal strength.

T-minus 1 hour and counting. The launch team has recycled the countdown back to the T-minus 60 minute mark and will re-perform the various tasks to get Minotaur back into a flight configuration again.

NEW LAUNCH TIME. Liftoff officially retargeted for 6:12 a.m. local (9:12 a.m. EST; 1412 GMT).

Still working to fix the ground glitch that is delaying this morning's Minotaur launch. Management is coordinating an official new launch time that will be announced shortly.

The problem holding up the countdown is not with the rocket. Officials report the issue involves ground equipment that is required to support the launch.

Minotaur is aiming for a potential new launch time of 5:20 a.m. local (8:20 a.m. EST). But that is preliminary and could change.

Launch team members are going through procedures to put the Minotaur in a good configuration to wait out this hold.

The countdown continues to hold. Clocks have been re-synced to T-minus 16 minutes.

To recap, there's a technical problem that engineers are troubleshooting right now. The issue forced the launch team to stop the countdown before going into the final readiness polls and retracting the thermal blanketing from the Minotaur rocket. There's no estimate on how long this hold will last. But launch still could happen this morning, if the problem can be resolved.

This hold means liftoff won't happen at 4:26 a.m. local. The launch time will be delayed by this unplanned hold.

Clocks were stopped at T-minus 15 minutes, 55 seconds.

The countdown has been halted due to a problem. Officials are working to get this issue resolved so the countdown can resume for liftoff this morning.

An issue has arisen that could stop the clock at T-minus 16 minutes.

Launch team members will be polled in the next few minutes to confirm everything is ready for liftoff.

T-minus 19 minutes. High-altitude winds are acceptable for launch.

T-minus 20 minutes and counting. Minotaur's target launch time remains 4:26:00 a.m. local.

T-minus 26 minutes. A safety test of the rocket's flight termination system is underway.

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

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

T-minus 36 minutes. Voltage and current readings from the rocket on external power are verified as normal by the launch team.

T-minus 40 minutes and counting. The launch pad danger area has been confirmed clear of all personnel.

Minotaur's guidance system is in alignment for today's climb to orbit.

The S-band data communications link tests were completed.

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

T-minus 60 minutes and counting. No problems are being reported with the Minotaur rocket as clocks continue to tick down for launch at 4:26 a.m. local.

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

As the countdown proceeds toward launch this morning, you can follow along right here on this page.

But if you will be away from your computer, sign up for our Twitter feed and get text message updates on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

Just 75 minutes remain in the countdown to launch of the Minotaur 1 rocket. The Orbital Sciences-managed rocket uses decommissioned first and second stages from Minuteman 2 intercontinental ballistic missiles and solid-propellant motors from the commercial Pegasus rocket program for its third and fourth stages. The vehicle was created to launch small satellites.

Minotaur 1 has flown eight times since 2000, successfully placing 30 spacecraft into orbit. Five missions originated from Vandenberg and three flew from Wallops Island, Virginia.

Today's launch will be the first flight with the National Reconnaissance Office as the customer.

Now 90 minutes from the scheduled launch time. This is a very quiet period in the countdown right now. Technicians will begin marching through the final launch checklist starting at T-minus 1 hour.

T-minus 2 hours and counting down to today's launch of the Minotaur 1 rocket carrying a technology demonstration payload for U.S. national security satellites from Vandenberg Air Force Base, California.

The launch support equipment is being powered up again.

Hands-on work at the launch pad has been finished. Crews are now departing Space Launch Complex 8 in preparation for this morning's predawn liftoff of the Minotaur 1 booster.

Arming, closeouts and launch site preps are complete at the Minotaur's pad on the south end of Vandenberg.

T-minus 2 hours, 36 minutes. The Orbital launch conductor has given the pad crew a "go" for arming and final closeouts of the Minotaur rocket.

If you will be away from your computer but would like to receive occasional countdown updates, sign up for our Twitter feed to get text message updates on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

T-minus 3 hours and counting.

Simulated liftoff testing is occurring to ensure that receiving stations will be able to detect the signal announcing Minotaur's launch.

The pre-launch checkout of rocket systems just wrapped up, allowing equipment to be powered down for now.

Minotaur's C-band beacon used for tracking the rocket during launch have been tested.

First and second stage engine steering sequence tests were accomplished as planned over the past couple of minutes.

The pre-flight alignment of the rocket's inertial navigation system has been verified complete. A steering test of the Minotaur engine nozzles is coming up.

Interrogation tests of the rocket's S-band transponder and link checks to the vehicle's flight safety system have been run. And the Minotaur's main computer is initialized and ready for the pre-flight guidance alignment.

T-minus 4 hours and counting. All systems on the launch vehicle are "green" with no issues being reported. The weather also remains acceptable for today's flight.

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 in its launch position away from the rocket.

"SLC-8 is austere but still a very effective system," Lt. Col. Timothy Harris, commander of the 1st Air and Space Test Squadron, said in an interview Thursday. "We have a tug, or forklift, that's attached to the mobile service tower. We fire that up and are able to tow the tower back and out of the way."

Tower rollback is underway. The service gantry that has shrouded the Minotaur rocket at Space Launch Complex 8 is slowly rolling away from the six-story booster in preparation for today's 4:26 a.m. PST blastoff. The mobile tower provided workers access to the various parts of the rocket and gave the vehicle shelter from the weather during the pre-launch mission campaign.

Technicians at Space Launch Complex 8 are ready to retract the pad's service structure from around the rocket.

Controllers have been testing communications and telemetry links at Vandenberg during this early portion of the countdown. The launch support equipment was turned on a short time ago, then approval was given to power up the rocket in preparation for upcoming pre-flight system testing.

T-minus 5 hours. And the launch countdown has begun for liftoff of the Minotaur 1 rocket on the NROL-66 mission for the National Reconnaissance Office. The launch team is starting to proceed through the countdown checklists to ready systems and the vehicle for blastoff, which remains scheduled to occur at 4:26 a.m. local time from California's central coast.

The likelihood of low-clouds and fog has been introduced into the launch weather forecast for Saturday's predawn blastoff of the Minotaur 1 rocket.

Meteorologists now expect some stratus clouds at the surface and fog that will reduce visibility to between two and five miles at the pad.

But none of that poses a constraint to launch. There's still a 100 percent chance of weather allowing an on-time liftoff. It's just an issue for photographers and spectators watching the ascent.

A technology trailblazer for U.S. national security spacecraft will streak into orbit before dawn Saturday atop a Minotaur 1 rocket from Vandenberg Air Force Base, California.

Liftoff is scheduled for 4:26 a.m. local time (7:26 a.m. EST; 1226 GMT) from Space Launch Complex 8, the southern-most pad at the Western spaceport.

"We're essentially clean and green at this point, pressing toward stepping into the count," said Lt. Col. Timothy Harris, commander of the 1st Air and Space Test Squadron. "We are not working any issues at this time."

The final launch readiness meeting was held Thursday afternoon and granted permission to proceed into the Friday night's countdown activities as scheduled.

"It's a five-hour count for a Minotaur 1," said Harris, who also serves as the Air Force launch director.

"Obviously I'm excited to have a chance to sit on console and be part of the final countdown. It'll be good fun."

Weather forecasters are predicting fine conditions for the launch opportunity and no chance of violating any of the strict rules governing a rocket flight.

With high pressure dominating California, the outlook calls for just a few clouds around 30,000 feet, good visibility, northeasterly winds and a temperature in the high 40s F.

A backup launch window is available on Sunday morning if the mission is postponed for some reason.

Check out a photo gallery of Air Force pictures showing the Minotaur rocket's prelaunch activities.

And watch this page for live updates during countdown and launch!

The U.S. military plans to launch a Minotaur rocket Saturday with a secret technology research mission for the National Reconnaissance Office, the government agency that oversees the country's spy satellites.

The solid-fueled Orbital Sciences Corp. Minotaur 1 launcher is scheduled to lift off some time Saturday from Vandenberg Air Force Base, Calif. The launch window is a secret for now, but the Air Force plans to announce a time for the blastoff Thursday evening.

The NRO is keeping quiet on the mission's specifics, but the agency says it is part of a science and technology development effort to lay the groundwork for future systems.

"If you have heard our director speak, one of his priorities is to have a healthy science and technology effort," said Rick Oborn, an NRO spokesperson. "This particular payload carries some of the work we do in techniques and methods to improve intelligence collection. All part of our work to keep improving the value of our data."

The satellite is known as RPP, which stands for the Rapid Pathfinder Program. The launch is codenamed NROL-66 in the spy agency's rocket acquisition naming system.

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