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The official launch countdown for Saturday’s launch of Space Shuttle Discovery and STS-121 began today at 5 p.m. EDT, with the launch clock set at T-43 hours. But for many at NASA, the countdown has been running since last July, when a piece of foam fell off Discovery’s external tank (ET) during launch. NASA managers quickly grounded the entire fleet, including Discovery, barely into her first day in orbit.

Since then, engineers have been struggling with how to best re-engineer the Space Shuttle’s ET to avoid the type of catastrophic impact damage doomed Columbia. The 15-story tall, bright orange fuel tank is covered by an inch-thick layer of polyurethane-like foam, which insulates the shuttle’s 535,000 gallons of cryogenic oxygen and hydrogen fuel, and prevents ice formation on tank exterior. Minute tank expansion can crack the foam insulation, allowing air into the cracks and causing pieces to fall off. When Discovery launched, a chunk of foam fell off the protuberance air load (PAL) ramp, a wedge shaped section of foam that serves as aerodynamic protection for fuel lines that feed the orbiter.

The end result of nearly a year of testing is the most significant re-design of the ET in its first flight in 1981. The PAL ramp is gone, and with it, 34 pounds of problematic foam insulation. Earlier this month on this page, astronaut Thomas D. Jones wrote that foam damage was not a major concern during his shuttle missions:

“My big worry during each of my four launches was that one of the three main engines would suffer an “uncontained” failure during the eight-and-a-half-minute climb to orbit—violently tearing itself apart and blasting shrapnel into the remaining engines and nearby systems. Moonwalker John Young used to tell us new astronauts how that would “blow the back end off” the orbiter—we wouldn’t be coming back. By comparison, tile damage from foam strikes seemed like a mere nuisance. I should have known better.”

Indeed, the Space Shuttle is the most complex machine ever built, and, Jones continues, “even after Challenger, we had perhaps fooled ourselves as to the complexities and dangers of human spaceflight. Columbia harshly reminded us that no flight is routine, and we will never make spaceflight perfectly safe.”

But with the time ticking away from the launch clock, Saturday’s launch might be facing a bigger problem than safety concerns: According to NASA, the launch weather officer reported today that “there is a 60-percent chance that weather may prevent launch on Saturday.” Forecasts for the following two days are the same.—Benjamin Chertoff; Additional reporting: Andrew Nusca

UPDATE: Today’s launch weather forecast has not improved since yesterday’s prediction of a 60% chance of a scrub due to thunderstorm activity in central Florida. Posted: 6/29/2006, 11:23 EDT -BC

Earlier: NASA’s “Go” for Launch, But Is the Space Shuttle?, The Great Space Shuttle Debate: Is the Space Shuttle Safe? A Special Report.

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The Hubble Space Telescope’s main camera has been offline since Monday, June 19, according to NASA. While scientists aren’t precisely sure why Hubble’s Advanced Camera for Surveys (ACS) reported invalid data and suspended operation, Ed Ruitberg, acting Hubble Space Telescope operations project manager at NASA Goddard Spaceflight Center, says engineers have been working to uncover why two of the three detectors in the ACS went into standby—cutting Hubble’s observation capacity in half.

“There’s information the computer collects about the health of the instrument, and one area was detecting invalid values,” Ruitberg says. “This effects two of the three detectors.” The third detector is still functioning.

The Hubble’s ACS was installed in 2002 to increase the telescope’s field of view, image quality and sensitivity. It collects 10 times the amount of data in the same amount of time as the camera it replaced, and detects wavelengths ranging from visible to far ultraviolet. The sensor, which is actually a system of three specialized cameras, forms detailed pictures of galaxies, neighboring stars, planets and planets-to-be.

This recent failure is similar to errors that have occurred in recent past, but the recovery might take longer than previous efforts, Ruitberg says. “We’ve had an instrument failure of similar kind in 2001. In that case, we switched to redundant electronics. We want to make sure we isolate the problem. We’re looking at doing that potentially as soon as Friday this week.”

While some potential culprits have been eliminated, the cause of the problem could be a low-voltage supply interface. The interface can be bypassed by switching to redundant electronic systems, Ruitberg says. “Once we switch to the redundant electronics, we’ll be back up and running, the full science program. The instrument is completely safe. We still have visibility. There’s no rush, and we’re not on any deadline.”

NASA can still use Hubble during the outage. “During this outage period, we’re deferring some of the ACS science,” Ruitberg says. “If you look in the end, we’re doing all the science we’re planning to do, we’re just doing it at a different time. We have a whole year of observing programs to work with.”—Andrew Nusca

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Researchers at IBM and the Georgia Institute of Technology announced today that they have surpassed the speed record for silicon-based chips by using a new semiconductor that operates about 250 times faster than those powering chips today.

The team used liquid helium to “freeze” the chip to minus 451°F.—just nine degrees above absolute zero, or the temperature at which all atomic motion is thought to cease—in a cryogenic test station.

“It allows us to make things faster,” says Dr. David Ahlgren, Senior Engineering Manager of Silicon-Germanium Technology Development at IBM. “We can operate and build applications that need very fast devices and trade off that speed for operating at lower cost.”

At 500 gigahertz, this barn-burning technology blazes past current operating speeds. The chip in your cellphone, for instance, operates at a paltry 2 gigahertz. “Right now there’s no market than being much faster than that,” Ahlgren says. Even at room temperature, he says, the new chip’s speed of 350 gigahertz still blows others out of the water.

“We’re exploring the fundamental speed limits in the way we build these devices,” says John Cressler, Byers professor of electrical and computer engineering at Georgia Tech and the lead researcher on the Georgia Tech team. “If we can understand them at low temperature, then we’ll be better understand them at room temperature.”

Cressler says the chip could be applied to anything from wireless networking to crash-mitigation systems in cars. The Georgia Tech team is also working with NASA to make electronic surfaces using silicon-germanium to handle the extreme temperatures of the moon, he says.

“It’s huge from a space exploration perspective,” Cressler says. “Now you have electronics that can work in an environment from plus 120 degrees C, to minus 180 degrees C.”

Cressler says research with silicon-germanium has taken off in the last few years and is growing rapidly despite concerns that silicon is “running out of steam.”

“In this case, we’re using bang-up engineering techniques,” he says. “I think we’re putting a new stake in the ground.“

The results of the test, conducted by a joint team of students from Georgia Tech and researchers from IBM Microelectronics, will be published in the July issue of IEEE Electron Device Letters.

“There’s a lot of us marching that path to see that it can be done,” Cressler says. “Can you rethink the way making electronics is practiced?” —Andrew Nusca

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Two years after NASA’s Genesis probe failed to deploy her parachute upon re-entry into the Earth’s atmosphere, investigators have found the culprit behind the crash: A design flaw resulted in the backwards installation of two critical sensors. Genesis was doomed from the start.

It was an ambitious mission: The probe was to spend five months orbiting the sun, collecting microscopic particles from solar wind before it returned to Earth, 1.8 billion miles later. And that’s the easy part. To preserving the delicate samples of solar wind, Genesis would not land on the ground. Instead, a helicopter crew would swoop in and pluck the probe out of the sky by her parachute. But the parachute never deployed, and the Genesis tumbled past the waiting helicopter. The craft slammed into the Great Salt Lake Desert, 85 miles southwest of Salt Lake City, just before 10 a.m. on September 8, 2004.

Although the mission was not a total loss—some samples survived the impact—the space agency quickly impaneled a mishap board to conduct an investigation. NASA’s follow-up mission, Stardust, was based on a similar design, and engineers wanted to make sure that the second craft functioned correctly (it did).

According to a report released by the board today, the root cause of the crash was an error in the craft’s original design. In their design of the probe, subcontractor Lockheed Martin inverted the two accelerometers that were supposed to trigger parachute deployment. “They installed [the sensors] the way the designs said,” Genesis project manager Donald Sweetnam says. “But they were backwards.” Investigators had suspected that this was the cause since as early as October, 2004.

Because of the error, the sensors never recorded the craft’s deceleration, an event that would have signaled that the craft had entered Earth’s atmosphere. “The capsule just came in hot and impacted on the ground without anything deploying,” says Sweetnam. “It was essentially like a baseball falling from 100 kilometers altitude.”

Genesis hit the desert floor at 193 miles per hour. “It was a pretty hard impact,” says Sweetnam. “Splat.” Engineers were unaware of an error until after the crash.

The tiny accelerometers, somewhat smaller than the metal ferrule of a No. 2 pencil, function as a switch in a circuit as the craft’s deceleration starts to flatten out. At 3 g’s, they were supposed to arm the pyrotechnics sequencer that would deploy the parachute.

Costing over $260 million Genesis was the first mission since Apollo to return extraterrestrial material to Earth for study. In their report, the mishap board included many suggestions for future missions, including more rigorously defined responsibilities within the project’s hierarchy of management. Most telling, however, was the recommendation that engineers should no longer assume that they already have full working knowledge of so-called heritage technology.

As things in spaceflight often go, engineers are hopeful that this accident will, ultimately, result in a safer space program. “My opinion is, doing things in space is difficult,” says Sweetnam. “You try as hard as you can—when you have a problem, you gotta come back and learn from it.” —Andrew Nusca

Related: On Board with NASA for Stardust’s Return

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European scientists unveiled a powerful new employee to help them in this millenium’s take on a space race to Mars and challenge U.S. exploration efforts of the planet: a robotic rover vehicle nicknamed “Bridget.”

In a new effort to find life on the red planet, the “autonomous robotic scientist” will serve as the keystone of what is intended to be the European Space Agency’s (ESA) most advanced attempt to find life on Mars. Designed primarily by UK scientists, the 10 ft.-by-6 ft., six-wheeled vehicle will carry sophisticated equipment and panoramic cameras as it patrols miles of Mars’ surface. The vehicle will also drill into the planet’s dusty ground, looking for amino acids, cell membranes, pigments and other signs of life, all without the need for detailed supervision from ground control.

The announcement of the new mission, named ExoMars and set for a 2011 launch, comes after the ill-fated, UK-led Beagle 2 stopped transmitting from its Martian orbit in 2004 and the ESA’s own Huygens mission to Saturn’s moon Titan, which arrived at its destination in January of last year. But the chance to earn some Martian bragging rights comes at a hefty price—Bridget’s price tag exceeds $184 million, and the ExoMars mission itself will cost upwards of $500 million. NASA’s Spirit and Opportunity cost $810 million together.

Meanwhile, members of the privately-funded German Mars Society are proposing a new vehicle that will survey large areas of Mars, at an altitude far lower than that of a satellite. Called Archimedes, the craft will hang from a balloon as it floats above the Martian surface after its projected 2009 arrival.—Andrew Nusca

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Competing with re-thought training wheels, parachute recovery systems, automatic candle extinguishers, off-road wheelchairs and every “Quad Zipper” in between, the winner of the History Channel’s Modern Marvels Invent Now Challenge wasn’t the flashiest invention on display in New York’s Grand Central Wednesday night—but it’s bound to make others green with envy.

After a decade and a half of development, 54-year-old former construction supervisor David Ward walked away with a $25,000 grant and a featured spot on the History Channel’s Great Inventions Week series for his Strawjet, a farm implement that processes straw in the field into a mat for use as composite building panel. The Strawjet doesn’t use the resins and chemicals used to make fiberglass or carbon fiber, creating instead a “greener,” more natural material with a low cost that allows it to used for humanitarian efforts in the Middle East.

But making the Strawjet a reality was not an easy process. “I was pretty sure that it was never going to work,” Ward said. “For many years, it was, ‘David, when are you going to get a real job?’”

A cross between a sewing machine and harvesting equipment, the machine’s inspiration came after a doctor who told Ward that tests came back with readings that were off the map from overexposure to worksite chemicals. Parts were the Strawjet were so difficult to come by that Ward said he had to manufacture his own – leading to a trial-and-error process that lasted nearly 15 years.

“Persistence is key,” Ward said. “There are a couple people all along who believe in you. You have to have somebody that believes in you.”

A pool of 25 semi-finalists gathered last night in Grand Central’s Vanderbilt Hall for the awards announcement, with almost 200 people present to cheer them on. Opposite the ceremony, children and passersby browsed a traveling exhibit featuring their inventions. Representing 17 states, the semifinalists were chosen in March from almost 4,300 submissions, from every state in the nation—a diverse cross section, from an 80-year-old businessman from Michigan to a 20-year-old inventor from New Jersey.

Apple Computer co-founder Steve “Woz” Wozniak was on hand to both introduce and inspire the new inventors, commenting that the motivation and compassion of the inventos led them to such great ideas.

“I wanted them to understand how clever thinking [the inventions] are,” Wozniak said. “Almost every one of these exhibits is worthy of winning, They all impressed me.”

In addition to Ward’s grand prize, four finalists were announced: Doctor David Cull, 47, for his “Hemoaccess Valve System,” designed to regulate blood flow in grafts used to connect patients with kidney failure for dialysis machines; 48-year-old firefighter Robert Kelly for his “Resc-hue Lite Line,” a waterproof, fire-resistant flexible light used for safety in low-light conditions; 51-year-old professor Sundaresan Jayaraman for his “Wearable Motherboard/Smart Shirt,” a garment equipped with sensors for unobtrusively monitoring the vital signs of the wearer; and, finally, 20-year-old Kristin Hrabar for her “Illuminated Nutdriver,” a driver equipped with LCDs on the outside of the tool and a laser light inside the tool’s hollow shaft, making it easy to use one-handed, without a flashlight in the other. Each finalist took home a $2,500 grant and a spot on the same History Channel series, which premiered Wednesday night at 10 p.m. EST.

Firefighter Kelly said he hopes his invention, inspired by the courage of his fellow firefighters, makes life safer on the job.

“It all goes back to firefighters.” Kelly said. “When they’re in trouble, who do they call? More firefighters. What I’m trying to do is save seconds when seconds save lives.”

Kelly said winning the award lends some authenticity to a design that went through some 20 prototypes.

“It feels great,” he said. “It makes it a little more meaningful. It makes a lunatic more legitimate.”

Hrabar, the youngest the 25, said her idea came to her in third grade, after she became tired of holding a flashlight for her father while he worked on household appliances.

“It was actually my third grade science project,” she said. “I had to wait for science to catch up with my ideas.”

Hrabar, who began to sell her invention on the market in 2000 at Laserdriverstore.com, said the process helped her overcome Attention Deficit Disorder and boost her self-esteem.

“I’m just really excited [to be a finalist],” she said. “It’s a really great feeling to be acknowledged by the History Channel and TIME magazine.”

As for Ward, the future holds many more prototypes – and the chance to construct a complete mock-up of a house using his winning invention. For young inventors, he said, “believing in yourself is the answer” to success.

But it doesn’t hurt to read a few magazines along the way. “I was talking to the guys who were designing [the exhibit] and said, ‘This has gotta look like the cover of a Popular Mechanics,’ ” he said with a smile. “God’s honest truth.”

As seen in Popular Mechanics.

Motorcyclists know how terrifying—and possibly fatal—a fall can be. Designed to complement the use of a helmet, Triple T Sales’ Hit-Air vest helps protect riders against serious injury by releasing inert gas into pockets in the vest, cushioning a rider’s neck, spine, rib cage, and internal organs if the rider is thrown off. The vest comes with an adjustable, coiled tether that, when attached to a horse’s saddle or the handlebars of a motorcycle or ATV, triggers the vest’s inflation of neck, body and hip cushions on the vest. After the accident, the gas cartridge is replaceable. Since the last thing anyone wants is asphalt for breakfast, think of it like a personal airbag. Too bad it doesn’t do anything to fend off the absent-minded driver behind you.—Andrew Nusca

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We see some pretty handy tools here at PM, but when it comes to moving bulky items, this one biggest cake we can find. For fewer than $40, the Forearm Forklift uses simple physics to help you (and a friend) carry that widescreen TV next door for the big game–so long as you don’t mind looking like a praying mantis doing it. At just over nine feet long, the 48” adjustable, safety-orange webbing straps can carry up to 600 lbs., reducing the stress on your body by 66% (while simultaneously increasing stress on your ego and self-esteem by an estimated 53%) and encouraging your spine to stay straight. Since you’re not using a handtruck or dolly, your carpet and hardwood floors stay undamaged. —Andrew Nusca

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Just what we all need: more 24. Apple Computer’s iTunes Music Store began selling Fox Entertainment programming yesterday in what is the store’s largest debut from a single network, adding 16 new series to the popular online store’s library. Already armed with shows from ABC, CBS, and NBC, the online store’s new addition brings its total collection to over 90 television shows from more than 20 networks. To date, iTunes has sold more than 15 million videos – about a million a week at $1.99 each. All of which adds up to my being able to watch Lost in Space without ever leaving the office. —Andrew Nusca

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As much as we like power tools, it seems some San Francisco fanatics have us beat. On Sunday afternoon at the Ace International Speedway, nearly 60 “bots” battled it out to reign supreme at the junkyard in the Power Tool Drag Races. Taking handheld power tools and modding them, participants raced their home brewed contraptions down a plywood track in weight classes such as “Super Stock,” “Awful Awful Altereds,” and “Funny Car” for an afternoon of “Massive Milwaukee” glory and “Devastating DeWalt” hilarity. Last year’s event even garnered a spot on the Discovery Channel, along with a prominent mention in our roundup of extreme hobbies (which, if you haven’t read, still makes us want to drop our copy editing pencils and pick up some rocket motors). Now where’s Tim Allen when you need him?—Andrew Nusca

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