The mystery satellite shot into orbit atop the classified Delta 4 rocket launch from Cape Canaveral last month has been spotted and identified by hobbyist trackers.

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The joint Air Force and National Reconnaissance Office post-launch press release has been issued and included these quotes:

"The outstanding ULA, NRO and Air Force partnership made yet another successful mission," said Lt. Col. William Heuck, 5th Space Launch Squadron commander.

This was the fifth in a series of six launches scheduled in a seven month period for the NRO.

"I am extremely proud of the entire government and contractor team who supported this launch. We have had an amazing five successful launches in the past 12 months, two in 2010 and three this year. I am looking forward to the launch of NROL-34 in April, which will conclude our most aggressive launch schedule in over two decades, said Col. Alan Davis, Director of the Office of Space Launch in the National Reconnaissance Office.

The Delta 4 rocket has flown into this now-standard news blackout for NRO missions after nose cone separation. The veil of secrecy surrounding the launch of the clandestine satellite means no further information about the progress of the upper stage engine firings and release of the payload will be announced in real-time.

T+plus 4 minutes, 42 seconds. The protective payload fairing enclosing the NROL-27 satellite atop the rocket has separated.

T+plus 4 minutes, 30 seconds. The cryogenic RL10B-2 upper stage engine has ignited!

T+plus 4 minutes, 16 seconds. The Common Booster Core first stage and the attached interstage have been separated in one piece from the Delta 4's upper stage. The upper stage engine's extendible nozzle is dropping into position.

T+plus 4 minutes, 10 seconds. MECO! Main engine cutoff confirmed as the RS-68 powerplant shuts down.

T+plus 4 minutes. The main engine is throttling down to 57 percent thrust in preparation for shutdown.

T+plus 3 minutes, 45 seconds. A spectacular sunset launch!

T+plus 3 minutes, 15 seconds. The main engine continues to perform well, consuming its liquid hydrogen and liquid oxygen propellants.

T+plus 2 minutes, 45 seconds. Delta is 34 miles in altitude, 63 miles downrange from the launch pad.

T+plus 2 minutes. The RS-68 is consuming nearly a ton of propellants per second as the powerplant pushes the Delta 4 rocket closer to the edge of space.

T+plus 1 minute, 42 seconds. Solid motor separation! The spent boosters have been shed from the first stage. Delta 4 continues powering its way toward space on the thrust generated by the RS-68 main engine.

T+plus 1 minute, 37 seconds. The twin solid rocket boosters have burned out of their propellant. Standing by for jettison.

T+plus 60 seconds. Now passing through the region of maximum aerodynamic pressure as the vehicle accelerates through the lower atmosphere.

T+plus 50 seconds. The launcher has broken through the sound barrier.

T+plus 30 seconds. The Delta 4 rocket is climbing away from the planet with its main engine firing at full throttle and the two strap-on boosters giving a powerful extra kick.

T-minus 10, 9, 8, sequencer now controlling, T-minus 6, 5, main engine start, 3, 2, 1 and booster ignition! The Delta 4 rocket begins another critical spacelift mission for U.S. national security as it clears the tower!

T-minus 12 seconds. Ignitors are armed and the residual hydrogen burnoff sparklers have fired beneath the main engine.

T-minus 22 seconds. The steering system for the twin solid rocket motor nozzles has been activated.

T-minus 30 seconds. Green board. All systems remain "go" for launch.

T-minus 35 seconds. Upper stage liquid hydrogen tank is confirmed at flight level.

T-minus 1 minute and counting. The ignition conditions for the RS-68 main engine are "go." The terminal countdown sequencer will take control at T-minus 8.5 seconds. Ignition of the RS-68 powerplant will follow at T-minus 5.5 seconds. The engine powers up to the 102 percent level of thrust for a computer-controlled checkout before liftoff.

T-minus 70 seconds. The Air Force-controlled Eastern Range has given its "go" for launch.

T-minus 75 seconds. The liquid hydrogen fuel tank on the upper stage is being secured for launch.

T-minus 80 seconds. Upper stage liquid oxygen tank has been secured at flight level.

T-minus 1 minute, 43 seconds. The first stage liquid hydrogen tank has reached flight level and pressure.

T-minus 2 minutes. The rocket's upper stage liquid oxygen tank is being secured.

T-minus 2 minutes, 35 seconds. The liquid oxygen tank in the first stage is confirmed at the proper level and pressure for flight.

T-minus 3 minutes, 15 seconds. Replenishment of liquid hydrogen and liquid oxygen to the Common Booster Core first stage is being secured in preparation to pressurize the tanks for launch.

T-minus 4 minutes and counting. Ordnance devices aboard the vehicle are being armed.

T-minus 4 minutes, 10 seconds. The systems of the first and upper stages of the Delta 4 rocket have switched from ground-fed power to internal batteries for launch.

T-minus 5 minutes and counting! The final phase of today's countdown has commenced for launch of the Delta 4 rocket carrying a clandestine satellite for the National Reconnaissance Office. Liftoff is set to occur at 6:38 p.m. EST from pad 37B at Cape Canaveral Air Force Station.

The mission director and the launch director have given approval to resume the count for liftoff at 6:38 p.m. EST.

The launch team is being polled again to verify all systems are "go" for the 6:38 p.m. EST liftoff time.

WINDS ARE GO. The most recent weather balloon has found acceptable winds as the conditions have eased.

An Air Force spokesman confirms the new launch time is the end of today's window.

NEW LAUNCH TIME. Liftoff has been retargeted for 6:38 p.m. EST. Engineers continue to work on the upper altitude winds and the shear between 10,000 and 15,000 feet.

Winds remain "red" for launch.

A new flight profile based on the latest winds is being loaded into the Delta 4 rocket's guidance computer.

Still standing by while engineers gather more wind data.

There's no estimate on how long this hold will last.

HOLD EXTENDED. The countdown will remain holding at T-minus 5 minutes to wait for the winds aloft to improve.

The final readiness polls of the launch team and mission managers have been completed. No technical problems are being worked. But upper level winds remain "no go".

Standing by for the launch team readiness check for continuing the countdown.

Upper level winds are still unacceptable for launch right now. The launch team is hopeful they will go "green" in time for an on-time blastoff at 5:57 p.m. EST (2257 GMT).

T-minus 5 minutes and holding. The countdown has entered a planned 15-minute hold. This pause is designed to give the launch team the opportunity to catch up on any work running behind schedule and verify all is in readiness for the final moments of the count. A series of management polls will be conducted during the hold to give approval to proceed with the launch.

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Now 25 minutes away from blastoff of the Delta 4 rocket and NROL-27 mission. The team is not working any technical issues and activities are running on the planned schedule.

The ULA launch team and management are guiding the countdown from the Delta Operations Center, located about 9,200 feet from the pad. The engineers overseeing the rocket and ground systems are located on the third floor and the Mission Directors Center room is on the fourth floor. Both rooms have a view of pad 37B and the Delta 4 rocket out their windows. Other rooms are also set up for engineering support.

The DOC was formerly built to support the Titan-Centaur program but was refurbished to support Delta 4.

The Air Force launch weather officer has given his final planned briefing to mission managers in the countdown. There's no worries about clouds, rain or surface winds today.

The issue about upper level winds is a vehicle engineering issue and that final decision on conditions aloft will be made later in the countdown.

A potential issue threatening an on-time launch could be the upper level winds and wind shear. Weather balloons are released throughout the countdown to measure the wind speeds and directions aloft. That data is computed by engineers to ensure the rocket's available flight profiles are safe to launch.

T-minus 30 minutes and counting. The countdown is headed to the T-minus 5 minute point where a 15-minute hold is planned. Liftoff is targeted for 5:57 p.m., which is the opening of today's launch window.

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With fueling of the Delta 4 rocket completed, this phase of the count is fairly quiet. Engineers are monitoring systems while the clocks tick down the final hour.

Everything continues to proceed on schedule at Cape Canaveral for liftoff at 5:57 p.m. EST.

The RS-68 first stage main engine spin start pressurization operation is starting.

Checks of the rocket's safety system have been completed successfully.

The countdown is entering the final 90 minutes until the Delta 4 rocket launch from Cape Canaveral at 5:57 p.m. EST. Here's a look at some stats about today's mission. This will be:

• The 353rd Delta rocket launch since 1960
• The 16th Delta 4 rocket mission since 2002
• The 13th Delta 4 rocket launch from Cape Canaveral
• The 7th Medium+ 4,2 configuration to fly
• The 9th Delta 4 under the ULA banner
• The 2nd Delta 4 launch this year
• The 12th use of Delta 4 by the Air Force
• The 5th classified Delta 4 for the NRO

The flight slews and commanding tests for the vehicle steering systems are complete.

Now two hours and counting.

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The launch team is kicking off the steering checks for the RS-68 main engine and RL10 upper stage engine, plus commanding tests with the solid rocket motors.

The radio frequency link checks between the rocket and ground have been performed successfully.

You can watch a live video webcast of launch right here on this page. Hit reload on your browser and the video stream will activate. The webcast will play as our text updates automatically refresh for the rest of the countdown and launch.

Radio frequency link checks between tracking facilities at the Cape and the launch vehicle are underway.

No technical issues are being tracked in the countdown and launch remains on target for 5:57 p.m. EST.

The thermal insulation inspections have been completed following fueling and there were no problems reported today.

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Engineers are conducting the standard evaluation of the Delta 4 rocket's thermal insulation following the loading of supercold propellants into the vehicle.

Upper stage liquid oxygen topping has commenced. That puts all four cryogenic fuel tanks aboard the Delta 4 rocket in topping mode.

The first stage liquid oxygen system is conditioned for flight.

The first stage liquid hydrogen tank is now entering the topping phase after the post-fueling tests wrapped up.

The topping mode is starting for the upper stage's liquid hydrogen tank.

The chilldown of the upper stage liquid oxygen system is reported complete, clearing the way for loading the rocket's tank with 4,500 gallons. This is the last of the rocket's four cryogenic supplies to be filled in today's countdown to launch.

Post-filling tests on the first stage liquid oxygen system are complete. The tank is now entering topping mode.

Fast-fill loading of the upper stage liquid hydrogen tank has been accomplished as fueling proceeds very smoothly this afternoon at Complex 37.

The "go" has been given for the upper stage liquid oxygen chilldown in advance of filling that tank.

The first stage liquid oxygen loading just finished. The tank has been loaded with its supercold oxidizer that is chilled to Minus-298 degrees F. Topping will be completed as the count rolls on.

Fast-filling of the first stage liquid hydrogen reservoir, the latest of the tanks to be loaded today, just wrapped up. After post-filling checks and valve tests, the tank will be placed in topping mode.

The launch team is actively loading the upper stage's liquid hydrogen tank with 10,000 gallons of propellant for the RL10 engine.

Now four-and-a-half hours till launch. The Delta 4 rocket's Common Booster Core first stage and upper stage are being loaded with supercold liquid oxygen and liquid hydrogen.

Complex 37 has two giant sphere-shaped fuel tanks to store the cryogenic liquid oxygen and liquid hydrogen. The LOX tank holds 250,000 gallons and LH2 sphere about 850,000 gallons. Complex 37 has two giant sphere-shaped fuel tanks to store the cryogenic liquid oxygen and liquid hydrogen. The LOX tank holds 250,000 gallons and LH2 sphere about 850,000 gallons.

The cryogenics are fed from the storage tanks through pipelines to the pad. For the Common Booster Core, the propellants are routed up to the launch table upon which the rocket sits. Tail service masts, the large box-like structures at the base of the vehicle, feed the oxygen and hydrogen to the booster via separate umbilicals.

The upper stage receives its cryos from the middle swing arm that extends from the Fixed Umbilical Tower to the front-side of the rocket.

The chilldown of the upper stage liquid hydrogen system is reported complete, clearing the way for loading the rocket's tank.

First stage liquid oxygen tanking operation is switching from "slow-fill" to "fast-fill" mode. The rocket will be loaded with 40,000 gallons of supercold LOX.

The launch team is starting the chilldown conditioning of the upper stage liquid hydrogen system now.

The first stage liquid oxygen chilldown is complete. Fueling will begin in the "slow-fill" mode to load a small percentage of the tank. The process then speeds up to the "fast-fill" mode until the tank is nearly full.

First stage liquid hydrogen tanking operation is switching from "slow-fill" to "fast-fill" mode.

And approval has been given to begin chilldown of the first stage liquid oxygen system. This preps the tank and pumping to guard against shock when the supercold oxidizer begins flowing into the rocket a short time from now.

The start of liquid hydrogen fueling of the first stage is now confirmed. Some 110,000 gallons of LH2 will fill the rocket's tank.

The cold gas chilldown conditioning of the liquid hydrogen system has been accomplished. Liquid hydrogen propellant will begin to flow into the first stage in "slow-fill" mode. That is sped up to "fast-fill" after a small portion of the tank is loaded.

Chilled to Minus-423 degrees Fahrenheit, the liquid hydrogen will be consumed by the RS-68 main engine along with liquid oxygen during the first four minutes of the launch.

The cold gas chilldown conditioning of the first stage liquid hydrogen system is underway as fueling ops commence today.

The formal "go" to begin fueling the Delta 4 rocket for today's flight.

T-minus 6 hours, 15 minutes and counting! The Terminal Countdown begins now for today's flight of the United Launch Alliance Delta 4 rocket with the NROL-27 mission for the National Reconnaissance Office.

The countdown has one planned built-in hold at T-minus 5 minutes lasting some 15 minutes, leading to liftoff at 5:57 p.m. EST (2257 GMT).

The launch pad has been verified clear of all personnel and systems now stand ready for fueling activities. The multi-step process of loading all four cryogenic propellant tanks in the two-stage rocket is scheduled to begin in the next half hour and continue into the mid-afternoon.

The launch team has been polled to verify all consoles are manned and ready to begin the Terminal Countdown when this hold ends at 11:27 a.m. No technical issues are being worked and the weather forecast is looking great.

The weather is beautiful along Florida's Space Coast for a Delta 4 rocket launch today. The latest forecast for liftoff time calls for just a few clouds, perhaps even clear skies, good visibility, northwesterly winds of 10 peaking to 15 knots and a temperature of 55 degrees. The odds of acceptable weather are 95 percent, with only a tiny hedge for winds gusting much stronger than expected.

The Terminal Count is scheduled to begin at 11:27 a.m. EST, some six-and-a-half hours before the targeted liftoff time. The countdown will be spent fueling the four cryogenic fuel tanks aboard the rocket, testing critical systems and verifying the hardware is ready to fly.

At 5:37 p.m., the countdown enters a planned 15-minute hold at the T-minus 5 minute mark. This offers managers a chance to perform final readiness polls of the entire launch team to confirm there are no issues or concerns before entering the last phase of the countdown.

Assuming all systems are go, clocks will resume ticking at 5:52 p.m. During those final five minutes, the rocket will switch to internal power, ordnance will be armed, all propellant tanks will be secured and the Range will announce a clear-to-launch for liftoff at 5:57 p.m.

T-minus 6 hours, 15 minutes and holding. A pre-planned one-hour hold has started ahead of the Terminal Countdown sequence. During this time the full launch team will be seated at the consoles, the pad is scheduled to be cleared of all workers and readiness polls will be conducted by mission management to ensure everyone is ready to proceed with the count.

The Terminal Count begins when the clocks resume ticking at 11:27 a.m., leading toward a liftoff of the Delta 4 rocket at 5:57 p.m. EST from Cape Canaveral.

The mobile service tower has been moved away from the Delta 4 rocket as launch day begins at Cape Canaveral Air Force Station for this mission carrying a payload to support the National Reconnaissance Office and intelligence community.

Retraction of the 330-foot tall mobile service tower from around the rocket occurred minutes ago in advance of final countdown preps. The wheeled gantry structure moved along rail tracks to its launch position about the length of a football field from the rocket's mount.

The 9-million pound tower shielded the Delta 4 from the weather, provided workers 360-degree access to the various areas on the vehicle and was needed to hoist the payload atop the upper stage during the launch campaign. The tower is 90 feet wide and 40 feet deep.

The Cape's Complex 37 is the same site used in the 1960s to fly unmanned Saturn 1 and 1B rockets that helped prepare for mankind's voyage to the moon. The site was rebuilt for the Delta 4 era, successfully supporting 12 liftoffs in the next-generation vehicle family so far.

A medium-class version of United Launch Alliance's Delta 4 rocket will give a lift to the National Reconnaissance Office and a clandestine cargo Friday night with blastoff from Cape Canaveral.

The launch is targeted for 5:57 p.m. EST (2257 GMT) from Complex 37 for the classified satellite deployment mission.

Weather forecasters are predicting 90 percent odds of acceptable conditions for launch, with only a sight concern of winds gusting to the 20-knot limit.

The cold front bringing wet weather across Florida on Wednesday night into Thursday is expected to clear out, leaving a launch time outlook on Friday night to include just a few low clouds, some scattered high cirrus, north-northwesterly winds of 10 peaking to 15 knots and a temperature of 65 degrees F.

Favorable conditions are supposed to continue through the weekend, if the backup launch opportunities are needed Saturday and Sunday.

The Delta 4 will head eastward after liftoff, its pair of strap-on solid motors delivering an added boost of thrust to the vehicle's cryogenic main engine for the initial ascent. The rocket is known as the Medium+4,2 configuration, which flew the Delta 4's maiden mission in 2002 and several times since then.

The National Reconnaissance Office is the secretive agency responsible for fielding the country's fleet of spy satellites for the intelligence-gathering community. The identity and purpose of the craft launching Friday are details the NRO doesn't advertise publicly .

This launch continues a remarkable surge of six rocket flights carrying new NRO satellites in just seven months, from start to finish.

• 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
• A small Minotaur 1 rocket for NROL-66 from Vandenberg on Feb. 6
• This Delta 4-Medium+4,2 for NROL-27 from Cape Canaveral is scheduled on Friday
• And an Atlas 5-411 for NROL-34 is planned from Vandenberg on April 12

Watch this page for live countdown and launch coverage throughout the day tomorrow.

And 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.)