Technology

By 9:45 AM, it's official—the field of eleven teams has already dwindled to eight. Oshkosh, AnnieWay, and Intelligent Vehicle Systems' entrants have ground to a halt, forcing them to drop out of the race. Oshkosh's demise was the most dramatic: It slammed into the side of one of the stage-set buildings in the mock urban environment. DARPA officials have declared an "All Pause," ordering the still-viable vehicles to stay put while organizers figure out how best to continue with the competition.

It's been interesting to observe some of the subtle ways the autonomous-vehicle community has changed in the two years since the last Grand Challenge was held. At 2005's event, the vast majority of the participants came from universities, but this year, most teams are built on collaborations between academia and industry—many of the vehicles are plastered with enough business logos to put NASCAR teams to shame (Google and VW are among the notable headliners). This shift seems like a sign that major corporate players are beginning to take notice of the vast profit-generating potential of this kind of technology. Today Victorville, tomorrow the world!—Elizabeth Svoboda

Many spectators have been congregating near a traffic circle early in the course, since it's where a lot of the action seems to be. A mandated lane change in the vicinity has been giving some of the vehicles fits; they appear to interpret the lane change incorrectly as a turn. In the end, most manage to make the lane shift after only a slight hesitation, but car #54, from the German team AnnieWay, lingered at the intersection for several minutes, backed up, paused, and backed up again before finally finding its way to the correct lane.

Meanwhile, elsewhere on the course, #26—the Team Cornell vehicle—came to an unexplained stop smack in the middle of a lane of traffic and lingered there for several minutes before sorting out the confusion and getting back underway. #21, Team Oshkosh's 24,500-pound TerraMax truck, just smacked into a barrier and shows no signs of being inclined to get underway again.

It's mishaps like this that make some participants pessimistic about the potential outcome of the race. "It's definitely a strong field, but the challenges are much more difficult than they were two years ago," says David Armstrong of the University of Florida's Gator Nation team, which was eliminated in the early rounds. "I don't think anyone's going to finish."—Elizabeth Svoboda

"Bot 3-2 has been given permission to commence operation," the announcer booms. "Victor Tango is on the move!" At just after 8 AM Pacific time, "Odin"—the modded SUV from Virginia Tech—purrs to life, passes in front of the bleachers to give spectators an eyeful, and disappears around the corner to a chorus of cheers. Odin's competitor number has a special significance; it honors the 32 students and staff killed in the recent Virginia Tech massacre. A few seconds later, the Stanford Racing Team's "Junior" gets the go-ahead. Junior lurches and pauses for a long moment just after exiting the blocks, but then regains its composure and follows Odin onto the course. The other nine vehicles follow, spaced a few minutes apart to decrease the odds of a collision.

A cortege of human-driven "traffic vehicles" escorts each autonomous entrant. The drivers are there to make sure the robotic vehicles don't "misbehave," as DARPA director Tony Tether puts it—but they could be putting their own lives on the line in the process. In earlier rounds of the competition, "on one merging turn, they had a bet on who was going to get hit first, and somebody won," Tether says. But not to worry, he quickly adds: "All these drivers are well-protected by cages built to NASCAR standards."—Elizabeth Svoboda

Race-day countdown has begun—it's 7:15 AM Pacific time, and the first robot vehicles will rumble from the starting blocks in less than an hour. Despite the morning chill in Victorville, the overall mood is exuberant. Inside the big white breakfast tent, team members in matching jackets bolt down cup after cup of coffee and hunch together over folding tables to discuss strategy. Out at the track, the vehicles slated to launch first are already pulling into their starting positions.

Flash
back to October 8, 2005: Stanford Racing Team's Stanley—a
tweaked VW Touareg with robotic innards—kicks up a cloud of
triumphal dust as it crosses the finish line at the DARPA Grand
Challenge in Primm, Nevada. Stanley was the first of four unmanned
vehicles that day to complete a 132-mile desert course replete with
rocks, treacherous inclines, and cliff-side hairpin turns. Though
Stanford's team grabbed the $2 million top prize, the event
represented a collective victory for autonomous vehicle developers.
After Stanley and its cohorts proved their mettle, self-driving cars
started to seem less like a Jetsons-inspired pipe dream and more like
the automotive wave of the future.

DARPA
is upping the real-world ante with this year's Urban Challenge, held
in Victorville, Calif. The field of 11 robotic finalists won't just
need to steer, turn, and brake successfully to navigate the 60-mile
course; they'll also have to obey traffic laws and signals, negotiate
merges on lane-marked roads, and carry out simulated battlefield
supply missions. The race organizers' immediate objectives are
military—Congress has pledged to replace one-third of its
operational ground fleet with autonomous vehicles by 2015—but if
this year's entrants can pull off bravura performances, the civilian
implications will be enormous. Robotics engineers envision a new
generation of computerized cars that will redefine the term
autopilot, ferrying passengers unassisted from point A to point
B, maintaining ideal speed at all times, and braking for dogs and
bikes faster than any human driver ever could.

The
first vehicle to complete the course will win $2 million, and second-
and third-place finishers will bank $1 million and $500,000
respectively. Flag fall will take place at 8 am Pacific time
tomorrow—stay tuned for up-to-the-minute live coverage of the race.—Elizabeth Svoboda

And then there were eleven. Yesterday, the Defense Advanced Research Projects Agency (DARPA) announced that it had narrowed the field for its Urban Grand Challenge to just under a dozen robotic vehicles. 35 teams were part of this week's qualifying rounds.

The finalists, which include a truck, a Prius and a sedan, will be competing this weekend for $3.5 million in prize money. To finish, each robot has to complete a 60 mile course in under six hours. And there's going to be live traffic—roughly 50 human-driven vehicles will be on the road. The robots will even have to deal with four-way-stops. Which would be amazing, since that's something most humans can't even figure out. Tomorrow, watch the race live here.—Gregory Mone

NASA is planning an emergency repair of the damaged solar panel astronauts discovered recently outside the International Space Station. Set to take place on Saturday, just a few days before the shuttle returns home, the plan will require two spacewalking astronauts, and it's risky but necessary.

If NASA does nothing, the tear could worsen and the entire panel might have to be jettisoned. Yes, the ISS does have a few more at its disposal, but this panel provides 15% of the station's electricity, and the ISS needs every bit of that to incorporate the planned new modules. The fix will require some ingenuity, as the ripped panel is far from an anchoring point for the spacewalking repairman. But NASA has pulled off plenty of feats like this before.—Gregory Mone

Astronauts working outside the International Space Station just noticed a tear in one of its solar panels. Two of these 110-foot-long panels were due to be unfurled, and the first unrolled without a hitch, but NASA halted the second one when its spacewalkers saw the damage.

This caps a tough few days for the station, as astronauts also confirmed a problem with one of the motorized joints that turns the panels to face the Sun. NASA had suspected there was a problem, and astronaut Dan Tani confirmed it up close, noticing shards of metal scrapings throughout the joint. Next up: figuring out where they came from.—Gregory Mone

(Image credit: NASA)

To see how to fly into an asteroid in three easy steps, launch the gallery here.

Spiderman is arguably the most popular cinematic superhero since Superman, and with the imminent release of the DVD of Spiderman 3 on October 30th, what better moment to do a little Spiderman 3 physics? In most successful movie franchises its hard for the sequels to match the original, and in the case of superhero action movies the cohesiveness of plot and dialogue tend to diminish in favor of ever more spectacular (and improbable) action sequences and special effects. Spiderman 3 is no exception to this phenomenon, however, that said, its still really fun to watch and the CG sequences are truly amazing. (check out the Birth of Sandman scene).

Now when analyzing the physics in a superhero fantasy obviously you have to suspend disbelief and accept the basic (impossible) premise of the movie if you want to have any fun. No matter how cool it would be, being bitten by a genetically enhanced super spider cannot change your own genetic structure and give you amazing super powers as it does Peter Parker. But at least hes still humanoid—unlike the Sandman who seems to offer proof that the human soul exists; not just because hes actually a nice guy deep down, but because you can blast him into a million little pieces (of quartz) thus destroying his body altogether, and yet he can reconstitute himself at will.

Allowing for such fantastic elements, it may be instructive to apply some basic Newtonian mechanics to a few of the action sequences in order to analyze Spidermans astonishingly resilient physiology.

We see in the climactic battle scene (scene 43 on the DVD), that Spiderman can survive a fall of 80 stories without a single broken bone, concussion, or presumably any internal bleeding. Using Newtons Second Law (Fnet = ma) lets calculate how much force the ground exerts on Spiderman upon impact.

First of all, for an 80 story plummet, Spidey will be close to his terminal velocity before he crashes. In the case of a skydiver, or a falling Spiderman, 60 m/s (about 130 mi/hr) is a reasonable and conservative estimate.

What forces are acting on our superhero during contact with the ground? There are only two: his weight force acting in a downward direction, and the upward force of the ground. It is the value of the force that the ground exerts on Spidey that we are concerned about. Applying the second law we get:

Fnet = Fground mg = ma

where mg is Spidermans weight (m is his mass which we estimate to be about 70 kg and g is the acceleration due to gravity), and a is the upward acceleration that Spiderman undergoes as the ground brings him to an abrupt halt. Since most collisions with hard objects (like concrete) occur on time scales of approximately one one-hundredth of a second we can calculate Fground as follows:

Fground = mg + ma = mg + mΔv/Δt

= (70 kg)(9.8 m/s2) + (70 kg)(60 m/s)/0.01 sec  ≈ 420,000 Newtons (thats 47 tons!).

Spideys acceleration upon impact is 6000 m/s2 or 600 gs. Since most bones will break if the body experiences forces exceeding 90,000 N, and concussions are pretty much inevitable for normal humans experiencing accelerations greater than 100 gs we can already see that Spiderman has no ordinary skeletal system!

In particular consider Spidermans skull. It must be constructed of some truly phenomenal material. In Spiderman 3 our hero experiences at least a half dozen collisions of his head with various solid objects. In the most violent of these (scene 47), Spidey gets flung into a steel beam with a speed that we estimate to be at least 15 m/s. Since he is brought to a stop by the beam and almost all of the force is exerted directly on his head (in about 0.01 second), the force on his head will be about:

Fnet = ma = mΔv/Δt = (70 kg)(15m/s)/0.01 second = 105,000 N.

According to some experiments, a direct impact to the skull exceeding 873 N will always result in a fracture (in fact the skull may fracture when exposed to forces much less than that), but Spideys skull is capable of withstanding forces at least 120 times as big. I guess when M.J. says Peter is hard-headed she really means it!  —Adam Weiner

On day two of the 2007 X Prize Cup, between dealing with Armadillo Aerospaces faltering attempts to win the Northrop Grumman Lunar Lander Challenge and serving as master of ceremonies for the days events, X Prize founder Peter Diamandis took a few minutes to talk to PopSci about the future of his organizations marquee event. Read the interview after the jump.—Seth Fletcher

Image Courtesy Zero-Gravity Corp

That tiny speck in the distance is Armadillo Aerospace's MOD 1 aircraft, right before not quite winning the Northrop Grumman Lunar Lander Challenge at the X Prize Cup in Alamogordo, New Mexico on Saturday. To win Level One, the lander has to rise up to 150 feet in the air, hover for 90 seconds and land on a pad 100 meters away. Then it has to do the same thing in reverse. MOD 1 nailed the first part, but failed in the final stretch of its reverse trip. A nozzle failure knocked the lander off balance with only seven seconds to go, causing it to miss the landing pad. As a result, the $350,000 prize is still unclaimed. —Seth Fletcher

Update: Sunday morning's attempt failed, too, again on the reverse trip. Sounds like the problem this time was a crack in the MOD 1's engine—MOD 1's new engine, which the Armadillo team installed after yesterday's failed try. Word is they'll try it Level One again this afternoon.

Another update: No dice for Armadillo this year. Their afternoon attempt failed; there was talk earlier today of a possible third attempt this evening, but according to an X Prize spokesperson, Armadillo founder John Carmack decided against it. That means it'll be this time next year, at the earliest, before anyone wins the prize.

Hauntingly fascinating is this speech by William Safire (most famous these days for his "On Language" column in the New York Times), drafted for President Richard Nixon to read in the event of a mishap during the Apollo 11 mission that would have stranded Neil Armstrong and Buzz Aldrin on the moon:

Fate has ordained that the men who went to the moon to explore in peace will stay on the moon to rest in peace.
These brave men, Neil Armstrong and Edwin Aldrin, know that there is
no hope for their recovery. But they also know that there is hope for
mankind in their sacrifice.
These two men are laying down their lives in mankind's most noble goal: the search for truth and understanding.
They will be mourned by their families and friends; they will be
mourned by the nation; they will be mourned by the people of the world;
they will be mourned by a Mother Earth that dared send two of her sons
into the unknown.
Read the full text here [via kottke.org]. —John Mahoney

At long last, the long-delayed A380 has finally made its first commercial flight—over 18 months behind schedule but still early enough to meet the conditions of our PPX proposition. A380FLIES has been delisted and paid out at POP$100 per share.

Personally I was skeptical, but the market was leaning toward success all along, with the proposition trading above $80 for the last few months. It closed at POP$99.75—doesn't get much more certain than that!

Above is a video of the historic touchdown in Sydney, courtesy of the UK's Telegraph. —John Mahoney