NASA
On Launch Pad 39A at NASA's Kennedy Space Center in Florida, workers removed the vent line attached to the ground umbilical carrier plate on shuttle Discovery's bright-orange external fuel tank. A hydrogen gas leak at that location during tanking for Discovery's STS-133 mission to the International Space Station caused the launch attempt to be scrubbed Nov. 5.
By
updated 12/1/2010 11:25:42 AM ET 2010-12-01T16:25:42

NASA is taking a close look at the December launch options for the final flight of space shuttle Discovery as engineers continue to study fuel tank issues that have kept the spacecraft grounded for weeks.

The next launch opportunity for Discovery's final mission is no earlier than Dec. 17 at 8:51 p.m. ET. But, in a news conference last week, shuttle program manager John Shannon said that he would only feel confident with a mid-December flight if engineering teams had a firm understanding of what initially caused the cracks in the metal ribs on Discovery's external fuel tank.

"We'll leave the option open for a launch window for Dec. 17, but a lot of data has to come together to support that," Shannon said in the Nov. 24 briefing.

Discovery was previously scheduled to lift off on Dec. 3 from NASA's Kennedy Space Center in Cape Canaveral, Fla., but top shuttle program managers opted to delay the launch to give engineers more time to identify and assess the risks. That setback came after several other delays that thwarted launch tries in early November. [ INFOGRAPHIC: NASA's Space Shuttle from Top to Bottom ]

Top shuttle officials will meet Thursday (Dec. 2) to review Discovery's status and discuss the potential of a December launch.

Discovery's launch options
Discovery's next available window opens on Dec. 17 and runs through Dec. 20, giving NASA three possible launch attempts in four days. Mission managers are unlikely to push beyond Dec. 20, however, as the agency would want to avoid having Discovery's 11-day mission overlap with the transition into the new year.

"They've never gone over the New Year's holiday," NASA spokesman Allard Beutel told SPACE.com. "They've never done it before, and they prefer not to, but it's not something so terrible. It's not that the system would crash the computers just have to be reset."

Beutel likened the problem to the Y2K issue of 2000, but stressed that it is not actually the same thing.

The computers on NASA's space shuttles are programmed so that at the end of the year, the systems need to be reset to reflect the date as Jan. 1, instead of Dec. 32, Beutel explained. In other words, at the end of the year, the shuttle computers have to be reconfigured to change from day 365 to day 1.

  1. Space news from NBCNews.com
    1. KARE
      Teen's space mission fueled by social media

      Science editor Alan Boyle's blog: "Astronaut Abby" is at the controls of a social-media machine that is launching the 15-year-old from Minnesota to Kazakhstan this month for the liftoff of the International Space Station's next crew.

    2. Buzz Aldrin's vision for journey to Mars
    3. Giant black hole may be cooking up meals
    4. Watch a 'ring of fire' solar eclipse online
"In general, to shut down and reset the computers, they need to be safely on the ground, landed or docked to the station," Beutel said. "In theory, they could do it while they're in flight, but that's never been done before."

Discovery is slated to deliver a new room and a helper robot to the space station during its final flight. The mission is NASA's second-to-last scheduled shuttle flight before the fleet is retired in 2011. An extra shuttle mission has been approved by Congress and President Obama, but final funding authorization by Congress is still pending.

Traffic jam in space
Space traffic is another consideration for Discovery's December flight options.

If Discovery is cleared to launch on Dec. 17, the shuttle and its six-astronaut crew will reach the International Space Station on Dec. 19, only two days after the arrival of three new station crewmembers also bound for the orbiting lab.

A Soyuz rocket carrying NASA astronaut Catherine Coleman, Russian cosmonaut Dmitri Kondratyev and European astronaut Paolo Nespoli is scheduled to launch from Kazakhstan's Baikonur Cosmodrome on Dec. 15.

The Soyuz TMA-20 will dock at the space station on Dec. 17, and while this could be the same day as Discovery's final launch, the two events will not conflict. After liftoff, it will take Discovery and its crew two days to enter into the station's orbit, catch up, and then dock with the orbiting outpost.

If, however, NASA is unable to launch Discovery in December and the STS-133 mission is pushed into 2011, the agency will have to establish the next launch window while balancing the space station program's already-full schedule.

"All windows are, to some degree, negotiable it's just how much you can negotiate," Beutel said. "But, that doesn't mean it's always going to be practical enough to be feasible. We have to work with the international partners and the station to change things around."

"There are a dozen and a half rockets and spacecraft heading to the station next year, so there's a lot of traffic," Beutel added. "Then there are spacewalks and work going on at the station. All that stuff has to be factored in."

What's next?
As it currently stands, NASA would be unable to launch Discovery during most of January, due to unfavorable sun angles that could cause parts of the shuttle to overheat while it is docked to the station. A couple of days may open up early in February, Beutel said, ahead of the next clear cut launch window on Feb. 27, which was originally reserved for Endeavour's final spaceflight the STS-134 mission.

  1. Space news from NBCNews.com
    1. KARE
      Teen's space mission fueled by social media

      Science editor Alan Boyle's blog: "Astronaut Abby" is at the controls of a social-media machine that is launching the 15-year-old from Minnesota to Kazakhstan this month for the liftoff of the International Space Station's next crew.

    2. Buzz Aldrin's vision for journey to Mars
    3. Giant black hole may be cooking up meals
    4. Watch a 'ring of fire' solar eclipse online
If needed, Endeavour's last mission could be rescheduled for the end of April, NASA officials have said.

Still, once Discovery has been given the clearance to fly, many of the subsequent decisions on how best to carry out the mission will be guided by the requirements of the space station and its program managers.

"The shuttle program is supporting the International Space Station," Beutel said. "It's ultimately what that program and our international partners need."

You can follow SPACE.com Staff Writer Denise Chow on Twitter @denisechow.

© 2013 Space.com. All rights reserved. More from Space.com.

Photos: Month in Space: January 2014

loading photos...
  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
  1. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  2. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  3. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  4. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments