The launch of space shuttle Discovery, planned for early this morning, was called off deep into the countdown due to inclement weather at Kennedy Space Center in Florida. NASA will try again in the wee hours of Wednesday, weather permitting. The launch time is set for 1:10 a.m. (Eastern Daylight Time)—which would provide sky-watchers another chance to see the orbiter climbing in the night sky—and the space agency forecasts a 70 percent chance of favorable conditions.

This is hardly the first time, of course, that a launch has been postponed in Florida's mercurial climate. Last month's STS-127 mission of space shuttle Endeavour to the International Space Station was pushed back three times due to weather, before the skies finally cleared. At that time, we checked in with space historian Roger Launius of the Smithsonian National Air and Space Museum to find out why NASA shoots all their rockets for manned missions from such a stormy place—you can read our Q&A with Launius here.

NASA has decided to proceed with a shuttle launch to the International Space Station (ISS) next week, having concluded that insulation foam losses from the external fuel tank, which occurred during the two previous shuttle launches, did not pose an unacceptable risk to the upcoming mission.

Space shuttle Discovery is set to lift off early Tuesday morning from Kennedy Space Center in Florida on a 13-day mission to the ISS. Discovery will deliver to the station new science gear and additional life-support equipment, as well as Stephen Colbert's namesake exercise device, the COLBERT treadmill.

There was much concern about the safety of the foam insulation that coats the shuttle's external fuel tank. Orbiters in both a May mission to the Hubble Space Telescope and last month's mission to the ISS showed dings from falling pieces of foam during ascent. A large-scale foam loss significantly damaged the heat shield of space shuttle Columbia in 2003, and the shuttle broke up on reentry, killing all seven crewmembers.

Charles Bolden and Lori Garver, President Barack Obama's selections to lead NASA, were confirmed as administrator and deputy administrator for the space agency, respectively, by the Senate yesterday.

Senator Bill Nelson, a Florida Democrat who knows Bolden from a 1986 space shuttle mission and who has campaigned tirelessly for his flight mate, promised via Twitter that "Charlie will bring back the magic from a time when we rode rockets to the moon." Bolden is "perfect to keep America leading in space, science and technology," Nelson also tweeted.

The International Space Station has been a colossal undertaking among five space agencies whose final price tag will likely be in the vicinity of $100 billion dollars. (The U.S. construction costs alone are estimated to be $31 billion.) Just this year the station finally reached its full capacity of six crew members, but it is still under construction—space shuttle Endeavour sits at the ready today to deliver to the ISS pieces of a Japanese experiment module.

But the ISS program manager for NASA is warning that without a change in policy, all that work will go plunging into the ocean in 2016, just six years after the scheduled completion of the station. "In the first quarter of 2016, we'll prep and deorbit the spacecraft," Michael Suffredini told the Washington Post. The ISS's long-term funding from NASA terminates in 2015, the newspaper notes.

Space shuttle Discovery touched down safely at 3:14 P.M. (Eastern Daylight Time) at Kennedy Space Center in Florida, completing its 13-day mission to the International Space Station (ISS). The landing time was pushed back from 1:39 P.M. due to uncertain weather at the landing site earlier in the day.

Discovery delivered a 45-foot (14-meter) truss segment to the ISS, completing the station's 335-foot (102-meter) "backbone," as well as the final set of solar arrays needed to power the station once its crew swells from three to six in the coming months. The ISS now boasts 38,400 square feet (3,570 square meters) of U.S. solar panels, nearly a full acre, generating about 120 kilowatts of electricity. (Unlike solar-powered buildings here on Earth, the space station doesn't need to worry about cloud cover.)

The next space shuttle launch has been pushed back again due to lingering safety concerns stemming from the last shuttle mission in November. NASA needs more time to analyze and possibly conduct further testing on the three flow-control valves that regulate the flow of hydrogen gas from the main engines to the external fuel tank, the space agency announced late Friday. Before the postponement, Discovery had been scheduled to depart on its servicing mission to the International Space Station as early as Friday, which was itself a pushback from an original launch date of February 12.

The safety issue came to light after the Endeavour mission in November, when engineers discovered that one of the valves had been damaged in flight. NASA removed and inspected the valves on Discovery but has been working to identify why Endeavour's valve broke and what safety risks a similar occurrence might pose to the Discovery mission.