Better to err on the side of caution was Monday's motto at NASA Mission Control in Houston, Texas. Persistent, low-altitude cloud cover over the landing strip at the Kennedy Space Center in Florida forced mission controllers first to delay the much anticipated return of Discovery for a few hours, then push it back a full day. The shuttle had been expected to touch down at 10:46 am CET, before the delay changed its landing window to 12:21 pm CET. NASA finally ruled that although the weather met the minimum requirements to give the landing a green light, it preferred to postpone.

On Tuesday, the first landing attempt is expected to come at 12:08 pm CET, if weather above the Kennedy Center permits. The shuttle will also have landing opportunities at Edwards Air Force base in California, or the White Sands base in New Mexico. A successful landing would be a welcome way to wrap up the first shuttle mission since the Columbia disaster in February 2003. NASA is naturally paying extra attention to this shuttle mission, which may be the last for a long time. The US Space Agency grounded its entire shuttle fleet after a piece of insulating foam fell from a fuel tank during Discovery's takeoff almost two weeks ago and damaged its underbelly. Experts say that the same problem resulted in Columbia's disintegration when it tried to re-enter Earth's atmosphere, a tragedy that took the lives of all seven astronauts. NASA earlier had said that the problem was fixed, but then relayed the frightening news that a similar incident had occurred during Discovery's takeoff.

Media coverage of repairs to Discovery's thermal shield has been extensive and the astronauts' spacewalk was even broadcast live on the Internet. Now everyone is holding their breath and waiting for a successful landing. If only the August weather would cooperate. (3 p.m. CET)

Jumbo Jet Countermeasures Would Mean Help for Boeing

With the trade battle between Airbus and Boeing set for a lengthy litigation phase at the WTO, you'd think the trans-Atlantic sparring would cool down over the summer. Both the US and the EU have said that they remain hopeful negotiations can still bring a solution to the subsidy dispute. But a new bill proposed in the US Congress may again throw oil onto the fire.

John Mica, Chairman of the US House of Representatives aviation subcommittee, has proposed legislation that would require commercial airplanes with a maximum capacity of over 800 seats to be equipped with electronic countermeasures to defend against attack from heat-seeking missiles. Funny thing, though, is that the rules would only apply to a single airplane: The Airbus 380. Smaller jumbo jets like the Boeing 747 would be exempt. It's all in the name of security, says Mica, who calls the larger planes "irresistible targets for terrorists."

Skeptics -- or anyone who has closely followed the Airbus/Boeing duel for that matter -- would immediately look for Mica's Boeing connection. But there is none. The same is not true for Northrop Grumman, however -- the company was a considerable donor to Mica's campaigns for Congress. And the defense manufacturer -- who also made the F-14 -- just happens to be developing systems that defend commercial airliners from missile attacks.

All this is starting to look like news from 30 years ago, when local authorities in New York tried to ban the British-French Concorde airplane from landing there because of noise concerns. If the legislation passes, it would be enforced in the US by the Federal Aviation Administration (FAA), so any A380 travelling there would have to be equipped with a countermeasure system. Most likely, this would mean all A380s, because airlines would want to be able to use the planes freely on diverse routes.

In today's security environment, it's hard to imagine a passenger who would say no to additional safety measures. But a bill that would affect only a single plane seems suspicious. And if it passes, it will be interesting to see just how specific the writing gets regarding the technology required. Till now, one of the best countermeasures for missile attacks is a relatively cheap system that drops flares to send incoming missiles off target. A plan to use tax revenue to outfit US commercial airliners was proposed two years ago by New York Senator Charles Schumer, but it has since floundered due to the high costs involved. Would forcing Airbus to adopt such systems really be fair? (12:22 p.m. CET)

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