Please create an account to participate in the Slashdot moderation system


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Journal Journal: Pro-TEK-shun for your car

Hoboken, NJ is paying $198,000 over the next 3 years so their
robotic parking garage will continue to function. Last week
hundreds of cars were jailed by the robotic garage's inability
to operate sans properly licensed software from Robotics Parking,
Inc., and the two sides had quite the spat when the companies'
operators were required to leave the garage so Israel-based
Ultronics could take over operations. Don't feel too bad for
the city, though, the 314-space garage, if full, takes in
nearly $63k a month, so the city gets half of the take to pay
off the capital expenses.


Journal Journal: How to Drive on Snow 2

I come from North Alabama, so I'm familiar with the problems driving on snow and ice. It's that one idiot out there who thinks (s)he can drive 50 MPH on snow that causes a problem. Perhaps some tips for drivers would be in order in addition to the sound guidance, "citizens are encouraged to stay off the roads today." I just vacationed in the Nevada mountains where they got 4 feet of snow in the week I was there, so here are my tips for driving on snow:

  • SNOW IS SLICK. ICE IS FOR HOCKEY. Snow is much slicker than rain on the street. You can control your car, but the slick snow must be respected. Ice is another matter entirely - it is absolutely treacherous. On ice, go straight and do not apply gas or brake. You have no traction on ice. (If we have a big ice storm, do not take a trip involving turns or acceleration.)
  • TEST BRAKING. Get going 10 MPH, check behind you to see nobody is there, and try stopping quickly. You will skid and probably swerve. Let off the brake until you're not skidding. Pump the brakes if you want to stop a little faster. Learn the limits of your vehicle. Be aware that it is much harder to stop going downhill than on level ground, and on a steep hill, it may be impossible to stop.
  • TEST STEERING. A simple curve in the road can be treacherous on snow and worse on ice. Know how your car behaves in snow, and be prepared for it to slide around.
  • STEER INTO THE SKID. To regain control of a skidding car, steer into the skid. Once you have control, decide whether it is best to turn more gently or try to stop. Allow plenty of space around your car in anticipation of skidding. It will happen.
  • DRIVE SLOWLY. 20 MPH is about as fast as you ever want to go on a snow-covered road, and then only when the road is perfectly clear of obstacles as far as you can see. Watch far ahead of your car. You will need the extra distance to respond on the slick snow. Make all movements slowly and gradually.
  • IF AT FIRST YOU DON'T SUCCEED, TRY, TRY AGAIN. If you get stuck going up a hill, you may be able to back up and try the approach again a few times.
  • LEARN TO DRIVE. Allow yourself plenty of time to get accustomed to driving in snow. Driving in snow is very different from driving in rain. In rain, the vehicle sometimes skids. In snow the vehicle frequently skids. Be patient and go especially slowly at first.
  • LOOK OUT! The driver who doesn't know these things is right around the corner unwittingly aiming for your bumper.

Journal Journal: Spooky Action Clocks

Do you have the time? NASA must have it quite precisely to pinpoint objects elsewhere (like rovers on Mars), and for your GPS receiver to work, the satellites must also know the time very precisely (and in turn, the receiver figures out the time as part of the solution to the equation).

Wouldn't you know it - someone wants a better clock. Here's an idea of how to make an atomic clock with precision of 1 second in 30 billion years using a trick einstein called "spooky action at a distance."


Journal Journal: Off-Road Wheelchair

Austrailian IT reports The US Food and Drug Administration has approved a wheelchair that can go up and down steps -- as well as shift into four-wheel drive for grassy hills and elevate occupants to standing height.

Called the iBOT Mobility System, the wheelchair uses sensors and gyroscopes to navigate stairs while balancing on two wheels.


Journal Journal: Infrared Telescope Launches

A new space telescope lifted off this morning. CNN reports, "SIRTF observes in the infrared light band and its scientists joke that SIRTF loks at the 'cold, the dark, and the dirty.'" It "will look at clouds of dust between stars. At shorter infrared wavelengths SIRTF will be able to see through the clouds, similar to how fog lams can view objects further away than normal headlamps." SIRTIF will also examine some of the most distant objects. SIRTF will orbit the sun, lagging behind the earth, which will give it a more stable orbit than an earth orbit.

Journal Journal: Engineers Should Have Known

NASA has released presentation slides analyzing the external debris impact observed by cameras 82 seconds after launch of Columbia on STS-107.

Slide 10 offers several scenarios where one tile is lost, and in each, they conclude "no issue", even though in the same block on the table they site temperatures approaching double the design temperatures (F). Aluminum melts at 1221F, but it gets brittle before then. The same frigging slide notes the design max temp at 350F.

My theory: Tile was significantly damaged by the foam as per case 1 in the analysis, and on reentry, the airframe heated to the 790F temperature they predicted. It vibrated, wiggled, and finally broke under the force of the atmosphere - about 8 minutes prior to LOS. After the airframe broke beneath one tile, plasma entered the wing, exiting as very hot gas by the aft sensors that failed first, then the plasma carried heat to the wheel well where we observed more failures. All the while, plasma was eating away at the airframe holding other tiles, and the zipper effect happened.


Journal Journal: Space Update

U.S. Air Force Space Command radar indicates that some space junk (rocket parts, paint chips, or a meteorite) passed very near or possibly hit Columbia during its second day of flight. Read more here and here.

No word yet on which wing they found parts of.

NASA is locked into using the Shuttle for the next decade or two because of International Space Station (ISS) considerations and the simple fact that the U.S. has no other manned launch vehicle at the time. They're talking about stepping up speed on the space plane production. Read more.

Did you realize we can't launch a manned rocket to the moon this year even if we want to? That's right. The first Saturn V rocket - the only design so far capable of reaching the moon - flew November 9, 1967. The last manned trip to the moon departed Earth on December 7, 1972 and returned on the 19th. They were on the moon from December 11 to 14. The last Saturn V, rather than going to the moon, hefted the U.S. space station Skylab into orbit on May 14, 1973.

Online, you can read the detailed history of the Saturn V, or read about the Apollo missions to the moon.

If the Shuttle doesn't go to the moon, then where does it go? It flies at an altitude of 200 miles above the Earth. It can't get much farther away than that because of its weight. Travelling at 17,500 miles per hour, the Shuttle still falls towards the Earth, but its forward speed allows it to miss the planet. Then why bother to go just 200 miles up? Because from orbit, everything in the craft seems weightless. Everything is falling towards the Earth (and missing it) at the same rate. In microgravity (that's what they call it because it's not purely zero-gravity), you can subtract the effects of gravity and learn more about processes on Earth.

While I was in Students for the Exploration and Development of Space, I attended a presentation entitled "Liquid Phase Sintering in Metals." Having recently heard a terribly boring presentation on Space Shuttle window construction, I wasn't too hyped about a talk with such an uninteligible title. It turned out to be one of the best, though it was somewhat technical. The problem is how we manufacture tools on Earth. Die cast metals invariably have bubbles in them, and the size and location of the bubbles severely weakens the material. By studying the bubbles in microgravity, we can learn how to make better tools on Earth. Read more.


Journal Journal: Historical Tile Damage

ET=external tank (the big orange thing)
SRB=solid rocket booster (the tall white rockets)

Atlantis sustained notable damage on STS-27 (the second flight after Challenger's explosion). They concluded it was from the right SRB nose cap which had an old-style surface. They also found ET foam and cork from SRB joints in the tile's pits. NASA made an interesting report in approving launch for STS-29.

In December, 1997, NASA was readying Endeavour for STS-89. They sanded the ET near the SRB joints, remarking, "While investigations into the cause of Columbia's unusual tile damage continue, managers hope the additional work will reduce the possibility of external tank foam debris contributing to Shuttle tile damage." One individual wrote about the damage.

Update: The Institute for Operations Research and the Management Sciences (INFORMS) has re-released a report commissioned by NASA about the risk to space shuttles from damage to the spacecraft's protective tiles.



Journal Journal: Picture of Cracks on Columbia's Wing?

The Israeli newspaper Maariv on Monday published a picture of Columbia purportedly showing two cracks on its left wing.

The picture was taken January 21 as video accompanying a satellite video conference between Israeli Prime Minister Ariel Sharon and Colonel Ilan Ramon, the first Israeli to travel to space.


I suspect the photo shows antennae. Otherwise, the astronauts would have been alarmed at the sight.


Journal Journal: Mourning Columbia

It's been a difficult two days for all of us. I seem to have worked through it much like Owen Garriott, Huntsville resident and astronaut on Skylab 3 and STS-9. He wants more information. I've sought whatever information I could get, and come up with my theories as to what went wrong.

I remember when I was in 7th grade at lunch and someone told me, "The Shuttle blew up." Since those folks knew I liked the space program and since they always picked on me anyway, I figured they were teasing me once more. A teacher set me straight. But then, we thought NASA could do no wrong. Now we know they have had accidents and have improved the systems, but we know they're not perfect.

A college friend called me from Memphis, Tennessee at 9:30 Saturday morning and demanded, "Where's the Shuttle?" I had the TV on in seconds, shortly before they first showed the video of the breakup without being sure it was the Shuttle. I had no doubt. I've been listening to press conferences and news ever since.

Media has focused attention on the piece of foam that fell from the external tank during launch. I still haven't seen a picture of it in which I could make out the foam, but I wouldn't be surprised if there was ice attached which would have made the foam harder and heaver than they figured in their analyses. But what could they have done? Absolutely nothing. I suppose they might have aborted the launch had they figured out what happened in time, but they weren't set up to do that.

The astronauts died doing what they loved to do. They wouldn't have been happy doing anything else. They knew the risks, as did their families. (Families weren't as aware of the risks 17 years ago.) We were better prepared for such a disaster as a community, too, having seen similar things before.

I remember watching Columbia's first flight on the TV. It was spectacular, and all too brief. It was an amazing feat of engineering and technology. I have a large picture of Columbia making its second landing, in White Sands, New Mexico, over the couch in my den. It's been my favorite decoration in the space and southwest-themed room. Now we have seen Columbia's final flight. It too was spectacular, and the craft's tenure too brief. A very difficult sight indeed.

The President and Congressmen have promised that space exploration will continue. And if Owen Garriott knows, it won't be as long a hiatus as it was with Challenger. He said, "This time, it could be a quicker turnaround. We have the space station to be concerned about." Here's the full article.

We must mourn the loss, learn from it, and continue our exploration of the cosmos. Space exploration is not without its risks, and we must accept risks to do anything worthwhile.

Yours in peace,
Jim Scarborough


Journal Journal: Mars Exploration Rover - Comments Due Today

NASA has put together another pair of rovers reminiscent of Sojourner, the little Mars buggy we all watched cruise around in July of 1997. It brought us stereo images from Mars and plenty of information on its rocks. The new rovers are designed to last longer and offer some improved instruments for the next exploration. Read about the Mars Exploration Rover project here.

Scientists propose to keep the electronics from freezing by means of some radioisotope heater units (RHU) combined with some electric heaters. Each rover's 11 RHU's would collectively contain 1 ounce of plutonium (Pu-238) and provide about 11 watts of heat from the radioactive decay. The RHU's together would then contribute 365 Curies. A couple of other instruments would use tiny radioactive samples for calibration or experiments (much like your smoke alarm's Americium), adding another 0.4 curies. NASA's Environmental Impact Statement (EIS) says "RHUs are designed to contain the plutonium dioxide during normal operations and under a wide range of accident environments. The integrity and durability of RHUs have been well documented by the U.S. Department of Energy."

People have been invited to comment, and comment they have. Bruce Gagnon, of the Global Netowrk Against Weapons and Nuclear Power in Space wrote a lengthy comment in which he describes a military development agenda buried within the scientific mission. Gagnon has been party to suits against NASA in the past.

Tony Rusi wrote a thoughtful reply to Mr. Gagnon's comment.

Please, look over the materials and take a moment to write today (the last day they're accepting comments) expressing your support for the program as outlined in the EIS. Send your comments to

Slashdot Top Deals

"The eleventh commandment was `Thou Shalt Compute' or `Thou Shalt Not Compute' -- I forget which." -- Epigrams in Programming, ACM SIGPLAN Sept. 1982