NASA managers, engineers and contractors met Friday for a program-level review of the shuttle Discovery's ground processing and readiness to launch Feb. 24 on a long-delayed space station assembly mission. An executive-level fight readiness review is planned for Feb. 18.

This illustration shows the shuttle docked to the International Space Station. Credit: NASA

Along with reviewing ground processing and external tank repairs, shuttle managers also are considering the possibility of staging what might be considered the ultimate photo op during Discovery's mission to deliver critical supplies and a final U.S. module to the space station.

The idea is to have a Russian Soyuz spacecraft undock so its three-man crew can photograph the station from a distance, showing the completed lab complex with the shuttle attached, along with Russian, European and Japanese cargo ships and crew capsules. Discovery's mission represents the last time a shuttle and all current types of visiting spacecraft will be present at the station before the shuttle fleet is retired later this year.

But the plan would require Russian approval and cooperation and it's not yet known if they will go along.

It is not a trivial undertaking. Anytime a manned spacecraft undocks, there is the possibility of a malfunction that could prevent a re-docking. In that case, the Soyuz and its three-man crew -- Soyuz TMA-01M commander Alexander Kaleri, Oleg Skripochka and Expedition 26 commander Scott Kelly -- would be forced to return directly to Earth, reducing the station's crew from six to three.

The Soyuz TMA-01M spacecraft is now docked to a space-facing port on the Russian segment of the station. Credit: NASA

"This only hit people's radar at the end of last week," said one NASA manager. While video and still photos showing the completed space station with a shuttle attached would no doubt be spectacular, at least some agency insiders believe the risks outweigh the benefits. Others, seeing a chance to capture a defining image of the shuttle-station complex, are hopeful the Russians will approve.

The Russians staged a similar photo operation on July 4, 1995, when the shuttle Atlantis undocked after NASA's first linkup with the Russian Mir space station. Just before Atlantis separated, cosmonauts Anatoly Solovyev and Nikolai Budarin undocked in a Soyuz spacecraft and photographed the shuttle's departure from a distance of about 300 feet.

Just after Atlantis undocked, however, Mir's central computer shut down, apparently misinterpreting the jarring caused by the shuttle's separation as a fault. The cosmonauts successfully redocked and eventually rebooted the computer. Whether that experience might affect how the Russians view the current proposal remains to be seen.

Atlantis undocks after its first visit at Mir. Credit: Roscosmos/NASA

NASA originally hoped to launch Discovery Nov. 1, but the flight was delayed because of bad weather and relatively minor technical snags. A launch attempt Nov. 5 was called off because of a gaseous hydrogen leak in a vent line attached to the ship's external tank. Then, during propellant draining operations, engineers discovered cracks in vertical rib-like stringers making up a central compartment in the huge tank.

Launch then was put on indefinite hold while engineers worked to repair the cracks and figure out what caused them in the first place. After a fueling test, extensive testing and additional inspections, NASA managers concluded the root cause was a combination of factors, including the effects of ultra-low temperature propellant, manufacturing issues and use of an aluminum-lithium alloy that was not as strong as expected.

Managers ultimately decided to install stiffeners on nearly all of the 108 stringers used in the so-called "intertank" section of the external tank. That work is complete, but tests and analysis have continued to make sure the modified tank has the required margin of safety.

In recent days, engineers have run into a variety of fresh problems with the gaseous hydrogen vent line that leaked Nov. 5, derailing Discovery's last launch attempt.

The leak was blamed on subtle alignment issues that, in the presence of low-temperature hydrogen gas, opened a leak path. Corrective actions were taken and during a fueling test Dec. 18, the fitting worked normally, without any significant leakage.

Because of trouble disconnecting the line later, technicians replaced a seal in the system this week. But during work to re-attach the vent line and rig it for launch, workers noticed unexpected movement in a component at the base of the umbilical plate that attaches the line to the side of the tank. Leak checks were successfully completed, but additional troubleshooting was planned.

In addition, a multi-blade tool called a "feeler gauge," similar to tools used to measure the gap in a spark plug, apparently came apart at the pad during work to rig the vent line fitting. Some of the tool's metal blades fell free and at least one of them hit Discovery's external tank. But a detailed photo analysis showed the damage was minor and no repairs were necessary.

In an unrelated issue, engineers preparing to service the system used to move the nozzles of the shuttle's two solid-fuel boosters heard an unexpected bang-like noise Monday. There were no obvious signs of trouble with the hardware and it's possible the sound was caused by a gust of wind slamming a door or an access panel closed on the launch pad gantry.

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Additional coverage for subscribers:
VIDEO: ROOT CAUSE OF SHUTTLE TANK CRACKS FOUND PLAY

VIDEO: WORK UNDERWAY TO REMOVE FOAM AND SENSORS PLAY | HI-DEF
VIDEO: SETTING UP ACCESS PLATFORMS AROUND TANK PLAY | HI-DEF

VIDEO: SHUTTLE ROLLED BACK TO ASSEMBLY BUILDING PLAY | HI-DEF
VIDEO: DISCOVERY DEPARTS LAUNCH PAD 39A PLAY | HI-DEF
VIDEO: LUNAR ECLIPSE OVER DISCOVERY PLAY | HI-DEF

VIDEO: HIGHLIGHTS FROM THE FUELING TEST PLAY | HI-DEF
VIDEO: RECAP OF THE FUELING EXERCISE PLAY
VIDEO: FUELING TEST COUNTDOWN UPDATE PLAY
VIDEO: COMMENTS FROM SHUTTLE LAUNCH DIRECTOR PLAY
VIDEO: GROUND UMBILICAL CARRIER PLATE CHECKED PLAY
VIDEO: INFO ON EXTERNAL TANK INSTRUMENTATION PLAY
VIDEO: DETAILED INFORMATION ON SPECIAL FUELING TEST PLAY

VIDEO: SHUTTLE DISCOVERY'S LAUNCH DELAYED TO FEBRUARY PLAY

VIDEO: FINAL PREPS FOR INSTRUMENTED TEST PLAY | HI-DEF
VIDEO: STRAIN GAUGES ATTACHED TO TANK PLAY | HI-DEF
VIDEO: BACKSCATTER INSPECTIONS OF TANK MIDSECTION PLAY | HI-DEF

VIDEO: INSTALLING DOUBLERS OVER STRINGERS PLAY | HI-DEF
VIDEO: GASEOUS HYDROGEN VENT ARM RETURNED PLAY | HI-DEF
VIDEO: DOUBLERS TO BEEF UP CRACKED BEAMS PLAY | HI-DEF
VIDEO: HYDROGEN FITTING IS REINSTALLED PLAY | HI-DEF
VIDEO: OPENING UP TANK'S ENTRANCE DOOR PLAY | HI-DEF
VIDEO: GUCP DETACHED AND SEALS REMOVED PLAY | HI-DEF
VIDEO: BROKEN FOAM REMOVED FROM THE TANK PLAY | HI-DEF
VIDEO: VENT ARM LETS GO FROM LEAKY GUCP PLAY | HI-DEF
VIDEO: DISCOVERY AWAITS REPAIRS TO TANK PROBLEMS PLAY | HI-DEF

VIDEO: INFORMATIVE DESCRIPTION OF TANK CRACK PROBLEM PLAY
VIDEO: DISCOVERY'S LAUNCH DELAYED TO MID-DECEMBER PLAY

VIDEO: GASEOUS HYDROGEN VENT ARM DETACHED FROM SHUTTLE PLAY

VIDEO: STS-133 MISSION PREVIEW MOVIE PLAY | HI-DEF
VIDEO: SHUTTLE DISCOVERY CREW BIOGRAPHIES PLAY | HI-DEF
VIDEO: ISS EXPEDITION 25-26 PREVIEW MOVIE PLAY | HI-DEF
VIDEO: SPACE STATION CREW BIOGRAPHIES PLAY | HI-DEF

VIDEO: POST-SCRUB NEWS BRIEFING ON LEAK PLAY
VIDEO: GASEOUS HYDROGEN LEAK SCRUBS LAUNCH PLAY | HI-DEF
VIDEO: BAD WEATHER DELAYS DISCOVERY LAUNCH PLAY
VIDEO: ELECTRICAL ISSUE NO LONGER A CONCERN FOR DISCOVERY PLAY
VIDEO: LAUNCH POSTPONED BY ELECTRICAL CONCERN PLAY
VIDEO: TUESDAY MORNING'S COUNTDOWN STATUS CHECK PLAY
VIDEO: DISCOVERY'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: COUNTDOWN PREVIEW BRIEFING AND WEATHER FORECAST PLAY
VIDEO: ANOTHER 24-HOUR DELAY ORDERED TO FINISH REPAIRS PLAY
VIDEO: LAUNCH DELAYED 24 HOURS BY LEAK REPAIRS PLAY

VIDEO: ASTRONAUTS ARRIVE FOR LAUNCH PLAY | HI-DEF

VIDEO: FLIGHT READINESS REVIEW SETS LAUNCH DATE PLAY

VIDEO: SHUTTLE AND STATION PROGRAM BRIEFING PLAY
VIDEO: THE STS-133 MISSION OVERVIEW PRESENTATIONS PLAY
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: IN-DEPTH BACKGROUND ON ROBONAUT 2 HUMANOID PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY

VIDEO: PAYLOAD BAY DOORS CLOSED FOR LAUNCH PLAY | HI-DEF
VIDEO: CREW LEAVES KSC FOR TRIP TO HOUSTON PLAY | HI-DEF
VIDEO: ASTRONAUTS INSPECT THE PAYLOAD BAY PLAY | HI-DEF
VIDEO: SHUTTLE EVACUATION PRACTICE PLAY | HI-DEF
VIDEO: ASTRONAUTS EGRESS SHUTTLE AS SEEN LIVE PLAY
VIDEO: ASTRONAUTS BOARD DISCOVERY PLAY | HI-DEF
VIDEO: SUN RISES ON LAUNCH PAD 39A PLAY | HI-DEF
VIDEO: LAUNCH DAY REHEARSAL BEGINS PLAY | HI-DEF
VIDEO: COMMEMORATIVE WALL SIGNING IN VAB PLAY | HI-DEF
VIDEO: CREW BRIEFED ON EMERGENCY PROCEDURES PLAY | HI-DEF
VIDEO: IN SHUTTLE TRAINING AIRCRAFT'S COCKPIT PLAY | HI-DEF
VIDEO: TEST-DRIVING AN EMERGENCY ARMORED TANK PLAY | HI-DEF

VIDEO: PRE-LAUNCH INTERVIEW WITH STEVE LINDSEY PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH ERIC BOE PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH AL DREW PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH TIM KOPRA PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH MIKE BARRATT PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH NICOLE STOTT PLAY

VIDEO: PAYLOADS INSTALLED INTO DISCOVERY PLAY | HI-DEF
VIDEO: MISSION PAYLOADS ARRIVE AT LAUNCH PAD PLAY | HI-DEF
VIDEO: CANISTER HAULING PAYLOADS TURNED UPRIGHT PLAY | HI-DEF
VIDEO: MODULE HOISTED INTO SHIPPING CANISTER PLAY | HI-DEF
VIDEO: WEIGHING NEW SPACE STATION MODULE PLAY | HI-DEF

VIDEO: GANTRY PLACED AROUND DISCOVERY PLAY | HI-DEF
VIDEO: SHUTTLE ATLANTIS REACHES PAD 39A PLAY | HI-DEF
VIDEO: CROWDS WATCH DISCOVERY'S FINAL ROLLOUT PLAY | HI-DEF

VIDEO: SHUTTLE HOISTED FOR ATTACHMENT TO TANK PLAY | HI-DEF
VIDEO: CRANE ROTATES THE ORBITER VERTICALLY PLAY | HI-DEF
VIDEO: DISCOVERY DEPARTS ITS HANGAR PLAY | HI-DEF

VIDEO: TIME-LAPSE SHOWS DISCOVERY ASCENDING IN VAB PLAY
VIDEO: TIME-LAPSE SHOWS THE MOVE TO ASSEMBLY BUILDING PLAY

VIDEO: DISCOVERY'S MAIDEN FLIGHT: FIRST TRIP TO VAB PLAY
VIDEO: DISCOVERY'S MAIDEN FLIGHT: ROLLOUT TO PAD 39A PLAY
VIDEO: DISCOVERY'S MAIDEN FLIGHT: TEST-FIRING ENGINES PLAY
VIDEO: DISCOVERY'S MAIDEN FLIGHT: ASSORTED VIEWS OF FRF PLAY

VIDEO: THE HISTORY OF SHUTTLE DISCOVERY PLAY
VIDEO: THE HISTORY OF SHUTTLE ENDEAVOUR PLAY
VIDEO: THE HISTORY OF SHUTTLE ATLANTIS PLAY

VIDEO: INSPECTION OF THE MISSION PAYLOADS PLAY | HI-DEF
VIDEO: ROBONAUT ARRIVES AT KENNEDY SPACE CENTER PLAY | HI-DEF
VIDEO: SPACE STATION'S SPARE THERMAL RADIATOR PLAY | HI-DEF
VIDEO: BLANKETING LEONARDO WITH INSULATION PLAY | HI-DEF
VIDEO: RACK INSERTED INTO LEONARDO FOR LAUNCH PLAY | HI-DEF
VIDEO: LEONARDO RETURNS FROM ITS PREVIOUS FLIGHT PLAY | HI-DEF
VIDEO: STATION'S SPARE PARTS DEPOT ARRIVES PLAY | HI-DEF

VIDEO: ORBITER'S PAYLOAD BAY CLOSED FOR ROLLOUT PLAY | HI-DEF
VIDEO: ASTRONAUTS VISIT THEIR SPACECRAFT PLAY | HI-DEF
VIDEO: CREW INSPECTS LEONARDO MODULE PLAY | HI-DEF
VIDEO: DISCOVERY RECEIVES ITS MAIN ENGINES PLAY | HI-DEF
VIDEO: FUEL TANK MATED TO SOLID ROCKET BOOSTERS PLAY | HI-DEF
VIDEO: HOISTING FUEL TANK INTO CHECKOUT BAY PLAY | HI-DEF
VIDEO: EXTERNAL FUEL TANK UNLOADED FROM BARGE PLAY | HI-DEF
VIDEO: MISSION'S FUEL TANK ARRIVES AT SPACEPORT PLAY | HI-DEF

VIDEO: POST-FLIGHT DESERVICING: OMS POD PLAY | HI-DEF
VIDEO: POST-FLIGHT DESERVICING: OBSS BOOM PLAY | HI-DEF
VIDEO: POST-FLIGHT DESERVICING: ENGINES PLAY | HI-DEF
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