NASA managers today proposed new launch dates for the first three shuttle missions of 2007. Planning dates for all remaining flights through the end of shuttle operations in 2010 also were updated based on preliminary launch processing assessments. While several near-term flights face delays due primarily to external tank deliveries and possible conflicts with Russian Soyuz launches, NASA still expects to meet its 2010 deadline for completing the space station and retiring the shuttle.

Shuttle mission STS-116 (Discovery) remains on track for launch Dec. 7, at 9:39 p.m. - NASA's first night launch since 2002. But an Air Force Atlas 5 rocket carrying a military payload currently is scheduled for launch on Dec. 7 from the Cape Canaveral Air Force Station and if that flight stays on track, the shuttle launch will have to slip a few days.

The goal of mission STS-116 is to attach a short spacer truss to the left side of the station's main solar array truss, to retract one of two solar wings providing interim power and to rewire the station to utilize electricity from arrays installed during a shuttle flight in September.

Shuttle mission STS-117 (Atlantis), the next flight in the sequence, slips from Feb. 22 to March 16, around 5:20 a.m., under the new manifest proposal. The goals of that mission are to retract the second interim power solar wing and to attach a new set of arrays to the starboard side of the solar power truss. The March 16 target launch date assumes the next Russian Soyuz flight moves to early April. If the Soyuz stay where it is currently scheduled - March 9 - STS-117 would slip to around March 23.

NASA managers are considering a design change for so-called ice-frost ramps on the shuttle's external tank. One flight test option under discussion is to modify the top three ice-frost ramps on the liquid hydrogen section of the tank slated for STS-117.

NASA is holding open the option of requiring a daylight launch for any external tank design changes to ensure good photo documentation. If that is required for STS-117, launch would slip to April 20. But a final decision on whether to implement an IFR redesign has not yet been made.

STS-118 (Endeavour), which had been targeted for a June 11 liftoff, moves to June 28 under the new manifest proposal. The goals of that flight are to attach an external equipment storage platform, another solar array spacer truss and a system that will permit docked space shuttles to draw power from the station. The crew for STS-118 includes astronaut Barbara Morgan, high school teacher Christa McAuliffe's backup in the original "teacher in space" program.

While not currently planned, STS-118 could be used to launch a refurbished control moment gyroscope to the station in place of the external stowage platform. One of the four stabilizing CMGs currently aboard the station has been taken off line because of excessive vibrations.

NASA plans to launch a multi-hatch connecting module known as Node 2 during the next flight in the sequence, STS-120 (Atlantis), which slips from Aug. 9 to Sept. 7. Again, there is a possible Soyuz conflict that could delay the flight a week or so.

Launch dates for flights after mission STS-120 are based on preliminary hardware processing assessments only and likely will experience subsequent adjustments.

Flight STS-122, featuring the European Space Agency's Columbus research module, remains targeted for launch on Oct. 17, 2007. But that date assumes the station astronauts can carry out three complex spacewalks to hook up Node 2 and a shuttle docking port between the end of STS-120 and the arrival of Columbus.

STS-123, launch of a Japanese pressurized experiment module, moves to Dec. 8 and flight STS-124, launch of Japan's Kibo research module, moves from Feb. 7 to Feb. 29, 2008.

Launch of a Hubble Space Telescope servicing mission - STS-125 - will be targeted for April 17, 2008, if NASA Administrator Michael Griffin ultimately gives his approval. A meeting to discuss the Hubble mission is planned for Oct. 27.

Here are the rest of the flights on the latest shuttle manifest:

06/19/08 - STS-119: Outboard starboard truss segment and arrays
08/21/08 - STS-126: Station resupply; last flight of Atlantis
10/09/08 - STS-127: Kibo exposed experiment facility; logistics
01/15/09 - STS-128: Crew accommodations; six-person crew capability
04/09/09 - STS-129: Logistics flight; last flight of Discovery
07/09/09 - STS-130: Logistics flight
10/01/09 - STS-131: Contingency flight
01/14/10 - STS-132: Node 3, cupola; last flight of Endeavour
07/09/10 - STS-133: Contingency flight

The manifest in graphic format is available here.