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How many astronauts have we had work on the underside of the shuttle, within arm's reach of tiles that are made of 10% material and 90% void, and the material's just 1-2mm fibre strands of silica, standing on the end of a wobbily robotic arm?

( http://science.ksc.nasa.gov/shuttle/technology/sts -newsref/sts_sys.html for details on tile composition)

As far as 'afraid to let them out the door,' you do realize these guys are putting the ISS together on spacewalks, and they've lost parts on those excursions as well. Also, suits have been damaged (gash through two layers of glove). You know why we haven't lost anyone on a spacewalk? Because at the first hint of any trouble, they're back in the shuttle.

Here's a physics question for you:

Astronaut standing on robotic arm underneath shuttle.
Arm wobbles towards shuttle, then down, away from shuttle.
What direction does the 200lb astronaut with 200lb gear go?

That's right. Toward the shuttle. Toward tiles that are 90% nothing. But this risk is worth trying out a complex repair maneuver? And you want the space program to continue?

The HRSI tiles are made of a low-density, high-purity silica 99.8-percent amorphous fiber (fibers derived from common sand, 1 to 2 mils thick) insulation that is made rigid by ceramic bonding. Because 90 percent of the tile is void and the remaining 10 percent is material, the tile weighs approximately 9 pounds per cubic foot.

http://science.ksc.nasa.gov/shuttle/technology/sts -newsref/sts_sys.html

My structural physics knowledge is a bit lacking, but something made of 10% rigid fibre 1-2mm thick and 90% void doesn't sound like the sturdiest structure to be applying force to.

I'm trying to think of a similar, down to earth item that mimics that structure...but best I can come up with would be like packing peanuts. Close, but it's not rigid enough.

Photons do not have mass.

From: http://imagine.gsfc.nasa.gov/docs/ask_astro/answer s/960731.html

The Question
(Submitted July 31, 1996)

Do photons have mass? Because the equations E=mc2, and E=hf, imply that m=hf/c2 . Is it so?

The Answer
No, photons do not have mass, but they do have momentum. The proper, general equation to use is E2 = m2c4 + p2c2 So in the case of a photon, m=0 so E = pc or p = E/c. On the other hand, for a particle with mass m at rest (i.e., p = 0), you get back the famous E = mc2.

Not to mention that objects also cast shadows in a vacuum - such as when the shuttlecraft crossed in front of the Enterprise.

Incredibly hard, yes. Unbreakable, no. I suspect if you actually shot that tile with a bullet, the tile would fracture. According to what I've read about the tiles, they're very good at protecting from heat, very hard, and very light. Materials with those characteristics (in the 1970-80s) are also very brittle.

For more information, including how to figure out which tile you have:
http://www-pao.ksc.nasa.gov/kscpao/nasafact/tps.ht m

In the second-to-last picture, there is a smaller yellow dot that appears to have a UV streamer about 1/6 to 1/8 as long as the UV streamer behind Mira. If that is a second (farther away?) star doing the same thing as Mira, then I wonder ... is there a common point of origin for both?

Parent is 100% right.

The first question that immediately struck me about this star's tail is:

The start is going through what? A cloud ? A dark matter thing? A particle wind ?

There is something, otherwise no tail, as for our Sun.

From the article linked to the news:

Really the article should have focused on this, it's a shame.

Another linked article states:

Parent is 100% right.

The first question that immediately struck me about this star's tail is:

The start is going through what? A cloud ? A dark matter thing? A particle wind ?

There is something, otherwise no tail, as for our Sun.

From the article linked to the news:

Really the article should have focused on this, it's a shame.

Another linked article states:

At best, Star Trek popularized scientific theories into science fiction, leading (some) people to be more interested in science. But even then, the people who were interested in these kinds of movies (the so called "nerds", "geeks", "losers", and other anti-social labels) were the people who were interested in science to begin with. Do you really think your average 60's football jock has became interested in physics as a result of watching Star Trek?

Doesn't really matter.

Only case in point you really need to know is that the guy who invented the cell phone (and I forget his name right now, one of the engineers at Motorola) has gone on record many times as saying the cell phone would not exist today if not for Star Trek. He set out to make the Star Trek communicator and that led to the first handheld cell phone. Motorola finally got it right with the StarTAC, which led to the Razr. It all grew out of Star Trek.

There was actually a TV show on the Discovery Channel (IIRC) called "The Science of Star Trek" that talked about all this, and lots more.

There are many, many things we have today as a direct result of Star Trek, and no doubt many more we'll have in the future that would have been considered impossible even just a few years ago. NASA right now has a page up that has this to say about universal translators as seen in Star Trek:

As this is used on the Star Trek shows, it's just an automagical device to enable characters to get through the stories. It would be too tedious and repetitious in a one-hour show for the characters to overcome real language barriers in a realistic manner in every show. The way the Enterprise crew can encounter an alien spacecraft, "hail them on standard frequencies," and establish instant telecommunications on their viewscreens is a preposterous shortcut to keep the plot from faltering. We can certainly dismiss the possibility of such an invention ever being built.

I'm not sure when this was written, but nowadays we have things like babelfish and google's language tools and Amikai (not a misspelling) that do instant translation fairly well. "Babelfish" itself is not based on Star Trek but instead on another piece of Sci-Fi, the Hitchhiker's Guide to the Galaxy, which is itself filled with ridiculously nonsensical things. Nevertheless, babelfish now exists. The algorithms are always improving. I don't see why it's impossible to think that someday we can add voice to those algorithms and put the whole thing on a chip with a small speaker that fits in your ear. (I also don't see what NASA's problem is with "standard frequencies" - few of the aliens in Star Trek live in a vacuum, they've all been in contact with other species and are usually part of one or another galactic organizations. Only non-warp enabled aliens live in a vacuum.)

The point is, Star Trek and other shows like it did drive a lot of our current technology - it only takes one person in the right position to do it - and it continues to drive our technology in ways we never would have thought possible before.

Here are the first hi-resolution shots of the damage and some cool ones of the station and shuttle and miscellaneous:
    http://www.nasa.gov/mission_pages/shuttle/shuttlem issions/sts118/multimedia/fd3/Image_Gallery_Collec tion_archive_3.html (page 3 at time of posting).

Even worse than the speeding bullet part is the section on this page(last paragraph) where it says that 'Coincidentally, Mira and its "whale of a tail" can be found in the tail of the whale constellation.' I think NASA just likes making dumb jokes and references in their media announcements.

Though the payload bay doors were opened without incident, their successful operation provided a clear view of the craft's Orbital Maneuvering System (OMS) pods, which showed signs of heat-shield tile damage. Mission Control counted 15 tiles missing from the OMS pods, which contained the vehicles in-orbit thrusters. Houston determined that the missing tiles would not present any problem, but mission controllers did not know if there was extensive tile damage on the orbiter's underside, an area more sensitive to reentry heating.

Major systems tested successfully on first flight of Space Transportation System. Orbiter sustained tile damage on launch and from overpressure wave created by the solid rocket boosters. Subsequent modifications to the water sound suppression system eliminated the problem. A total of sixteen tiles were lost and 148 tiles were damaged.

Though the payload bay doors were opened without incident, their successful operation provided a clear view of the craft's Orbital Maneuvering System (OMS) pods, which showed signs of heat-shield tile damage. Mission Control counted 15 tiles missing from the OMS pods, which contained the vehicles in-orbit thrusters. Houston determined that the missing tiles would not present any problem, but mission controllers did not know if there was extensive tile damage on the orbiter's underside, an area more sensitive to reentry heating.

Major systems tested successfully on first flight of Space Transportation System. Orbiter sustained tile damage on launch and from overpressure wave created by the solid rocket boosters. Subsequent modifications to the water sound suppression system eliminated the problem. A total of sixteen tiles were lost and 148 tiles were damaged.

His point was correct. I think you were a little harsh. http://science.ksc.nasa.gov/shuttle/missions/sts-1 /mission-sts-1.html The first space shuttle Columbia STS-1 went up in 1981 and came back with 16 tiles lost and 148 damaged.

The Columbia Accident Investigation Board report is unambiguous on this: "a breach in the Thermal Protection System on the leading edge of the left wing, caused by a piece of insulating foam which separated from the left bipod ramp section of the External Tank at 81.7 seconds after launch, and struck the wing in the vicinity of the lower half of Reinforced Carbon-Carbon panel number 8." In Elsewhere, I've seen the size of the foam estimated as 50 cm x 40 cm x 15 cm. The report also says that NASA's decision-making and management processes were broken. (The CAIB report is quite readable and interesting, and has lots of photos -- have a look if you're at all interested in the shuttle.)

Since the snowball fight is not sufficient to convince you, as it was to my 5 year old son, I'll do the physics:

From http://spaceflight1.nasa.gov/shuttle/reference/bas ics
It actually goes supersonic at about A1=8500 m, and hypersonic at A2=50km altitude. aerodynamic load at A2 is similar to 140km/hr at sea level.

The force on a foamball or snowball will be the same. The foamball will impact with a higher speed, but the iceball will spend more time in the airstream, gaining much more momentum, so what is worse?
Since v=2as, F=ra, E=1/2mv^2 where v is impact velocity, a is acceleration and s is distance it is falling before impacting. F is aerodynamic force and equals density r, times acceleration (For a unit size piece). E is impact energy.
Solving for Energy E=2rF^2s^2. Only density is a variable. The rest is constant, so we revrite as

Impact energy E=kr, where k is a constant, and r is density. So ice is worse than foam.

You realy cant count the Enterprise in this, it was a test orbiter that never left the atmosphere.

http://science.ksc.nasa.gov/shuttle/resources/orbi ters/enterprise.html "Following in the Enterprise's, the orbiter Columbia was created and it became the first Space Shuttle to fly into Earth orbit in 1981. "

When looking at missing/damaged tiles, the only shuttles that can be considered are the ones that acualy had to go through the ordeal of launch, reentry, and landing.

Tiles have gone missing during launch from the shuttle before and landed ok. The Columbia disaster happened due to the damage of the wing beyond the tiles. There was litteraly a hole in the leading edge of the wing.

Another thing to keep in mind is these tiles, while able to withstand great heat, are also fragile. http://science.ksc.nasa.gov/shuttle/technology/sts -newsref/sts_sys.html#sts-hrsi

I would be more worried finding the skin under the tile was damaged than finding the tiles were damaged. I think this is more PR of them showing they are trying to keep it safe and reactionary journalism than an acual problem.

With that said, I also reserve the right to be wrong.

You realy cant count the Enterprise in this, it was a test orbiter that never left the atmosphere.

http://science.ksc.nasa.gov/shuttle/resources/orbi ters/enterprise.html "Following in the Enterprise's, the orbiter Columbia was created and it became the first Space Shuttle to fly into Earth orbit in 1981. "

When looking at missing/damaged tiles, the only shuttles that can be considered are the ones that acualy had to go through the ordeal of launch, reentry, and landing.

Tiles have gone missing during launch from the shuttle before and landed ok. The Columbia disaster happened due to the damage of the wing beyond the tiles. There was litteraly a hole in the leading edge of the wing.

Another thing to keep in mind is these tiles, while able to withstand great heat, are also fragile. http://science.ksc.nasa.gov/shuttle/technology/sts -newsref/sts_sys.html#sts-hrsi

I would be more worried finding the skin under the tile was damaged than finding the tiles were damaged. I think this is more PR of them showing they are trying to keep it safe and reactionary journalism than an acual problem.

With that said, I also reserve the right to be wrong.

6 inch by 6 inch but can very in size depending on location on the shuttle.

Those are some dinky little low resolution pics. Here's one of Endeavor with the Earth as backdrop, today's NASA "Image of the day". Yesterday's is spacewalking astronaut Rick Mastracchio fixing something outside the space station. Here it is taking off, and here's another liftoff pic. These are all of the present mission that's still up there inspecting tiles. Here is the "Image of the day" gallery. These are bigassed, high resolution pictures, most of them breathtaking.

-mcgrew

Those are some dinky little low resolution pics. Here's one of Endeavor with the Earth as backdrop, today's NASA "Image of the day". Yesterday's is spacewalking astronaut Rick Mastracchio fixing something outside the space station. Here it is taking off, and here's another liftoff pic. These are all of the present mission that's still up there inspecting tiles. Here is the "Image of the day" gallery. These are bigassed, high resolution pictures, most of them breathtaking.

-mcgrew

Those are some dinky little low resolution pics. Here's one of Endeavor with the Earth as backdrop, today's NASA "Image of the day". Yesterday's is spacewalking astronaut Rick Mastracchio fixing something outside the space station. Here it is taking off, and here's another liftoff pic. These are all of the present mission that's still up there inspecting tiles. Here is the "Image of the day" gallery. These are bigassed, high resolution pictures, most of them breathtaking.

-mcgrew

Those are some dinky little low resolution pics. Here's one of Endeavor with the Earth as backdrop, today's NASA "Image of the day". Yesterday's is spacewalking astronaut Rick Mastracchio fixing something outside the space station. Here it is taking off, and here's another liftoff pic. These are all of the present mission that's still up there inspecting tiles. Here is the "Image of the day" gallery. These are bigassed, high resolution pictures, most of them breathtaking.

-mcgrew

Those are some dinky little low resolution pics. Here's one of Endeavor with the Earth as backdrop, today's NASA "Image of the day". Yesterday's is spacewalking astronaut Rick Mastracchio fixing something outside the space station. Here it is taking off, and here's another liftoff pic. These are all of the present mission that's still up there inspecting tiles. Here is the "Image of the day" gallery. These are bigassed, high resolution pictures, most of them breathtaking.

-mcgrew

I wouldn't call those too exclusive.... look at the "3D Video of Endeavour Tile Damage" video on this page: http://www.nasa.gov/mission_pages/shuttle/main/ind ex.html

I especially like this flaw:

"The earth receives 51 billion kilowatts of solar energy every second."

Really? Kilowatts per second? So it's increasing? Try kilowatts. No scientist would make this mistake. It's obvious, you buy lightbulbs by the watt, not watt per second. This website is much better (from NASA): http://earthobservatory.nasa.gov/Library/Oven/

"the Sun deposits 342 Watts of energy into every square meter of the Earth."

Watts per square meter is much better. Thank you NASA. Saladin: stop embarrassing pro-evolution.

I see this all the time. A children's book stated that Hawaii lies 2,500 miles from the continental U.S. and helpfully converted it to 4,023 km. It continued that some people were surfing on 3-foot, or 91-centimeter, waves.

And look at this idiocy from NASA:

within a minute the probe will slow down from 20,000 km per hour (12,427 miles per hour) to just 300 km per hour (186.4 miles per hour).

(Correct answers: 4,000 km, meter-high, 12,000 or 10,000 mph, 200 mph.)

The shuttle stack effectively throttles down when the solids burn out.

The SSME's are throttled to 74% or so mid solid flight to avoid max Q. reference. Check 6:36 pm.

One site I found says that there is a throttle down at 7:40.0 to 3G before MECO at 8:00.0 so acceleration can't be much above 3G at 7:40 and would surely not go above 5 at cut off without throttling.

I'm not convinced, but I don't have my numbers in front of me. Remember, towards the end of flight is when you are having the biggest fractional change in mass over time, which is the biggest change is acceleration

5G is OK for a human crew but outside design limits for the shuttle and the shuttle/ET combination, which must be the reason for keeping it at 3G.

The shuttle replacement (Constellation) is stacked vertically, yet the second stage engine (J2-X) retains the ability to throttle. It is very simple to convince yourself this is necessary! In order to get to space you need a lot more fuel than dry mass. (the equations are left to the interested student ... I'll use a ballpark number) Lets say you need 15kg of fuel per 1kg of dry mass. The upper stage gets you half way there, delta-v wise, so you only need 7kg of fuel per remaining kg of mass. So you are clipping along at 3g at first stage burnout T=m*a. Now, you burn off 7/8ths of your mass. Thrust is constant, mass goes down by 7/8ths. Now tell me what happens to acceleration? It increases. Greatly :)

Let's stick with peer-reviewed research, ok? This is a press release. Show me the science this is based off.

You won't be able to tell me that, because CO2 records are maintained for only one place on the planet ... the side of a volcano in Hawaii! That's just false. We have CO2 measurements from all over the world; and the Hawaii measurements are hardly suspect, given the altitude of the measurements.

The press release? That's exactly what I'm talking about. The climate change deniers are putting all their energy into making press releases and publishing articles in the newspaper - instead of publishing research in scientific journals. Where's the research? Don't link to press releases. Link to primary research. You won't be able to - because there isn't any. It's a scam.

Photos of the damage to STS-118 can be found: here, here and here..

Photos of the damage to STS-118 can be found: here, here and here..

Photos of the damage to STS-118 can be found: here, here and here..

"If we are experiencing a global warming trend caused by greenhouse gas emissions, the 80s (and 70s, and 60s, and 50s, and 40s) should have been hotter than the 30s. They weren't. How do you explain this anomaly?"

As many others have pointed out, this data is for the U.S. only. Globally, the 30's don't stand out at all. The 30's were only hotter in the U.S.

Globally, the average 5-year mean temperatures have been the warmest on record over the last 25 years. Over that period the temperatures have been steadily going up, and the rise in temperature even appears to be accelerating.

It was one data set that contained an error, and a fairly marginal one at that. At the cost of repeating myself, go take the corrected data, plot it, and see that not much has changed. Of course, saying "the hottest year is no longer 1998, it's 1934! Its teh climate illuminati!" makes more of a headline.

You conveniently seem to forget that:

1. This error is of no significant consequence to global warming theory. 1934 was a spike, 1998 is part of a trend.
2. There are bunches of other data sets, by NASA and other authorities. This is just one data set that happened to contain an error. Big deal.
3. The corrupted data set was valid for the USA only, not the world. It is not a determining data set for global warming.

Here we go again. The vast conspiracy against solar and wind by those evil baddies. Please.

Why not solar? The Solar Constant, that's why. 1.367kW/m^2. Typical yield is closer to 1kW/m^2. Then some genius suggests that we cover an area roughly the size of Arizona with solar cells to generate all of the power. Riiiiiiiiight. "Just cover all of the roofs, and we'll be set!" Riiiiiiiiiight.

http://apod.nasa.gov/apod/ap970830.html

Those are the roofs. Added up, they might add up to Arizona. Not likely though. Now imagine that you wanted to cover up Arizona with big pieces of paper, the whole state. I want you to imagine the scale of a project like that with just paper. Now I want you to reflect on the difficulty inherent with replacing all of that paper with silicon semiconductors that currently require clean rooms for manufacture.

Nevermind that we can't get 50% cells to last more than a couple months let alone ten years, and that's the expensive, lab-grown variety. But people still hold out hope for "printable" solar panels that get 50% efficiency and last fifty years.

Stirling engines? Sure, cover Arizona with Stirling engines. That's feasible. Riiiiiiight.

And wind? Yeah, let's hear it for the 5 or 6MW wind generators! Well, until you see the stats on land area they use up. Feel free to look up pictures of how big 6MW wind generators actually are. However, most generators aren't anywhere near that big. In fact most wind farms (collections of generators) tend to add up to that 5 or 6MW range all together. There just isn't enough wind. You can't produce energy out of nothing. It has to come from something. If the wind isn't blowing hard enough, no amount of money and research is going to extract thousands of megawatts out of it.

What? Offshore wind generators? Uh hunh, no maintenance involved in keeping mechanical devices with large moving parts in working order in the middle of those salt water oceans. No sir! We could just turn them on and walk away. Let's not even think about those big power cables headed for shore. Nope, those aren't a target for mischief.

Kites? Sure, as long as we ignore the fact that no one has actually been successful at getting 100 kilowatts-hours out of that even for a single hour. I haven't yet heard of a meager first step yet let alone something approaching a working prototype.

Or traffic wind generators? That one takes the cake. If someone can't grasp why traffic wind generators are a moronic idea, that person can't handle the real world. Transferring energy from wind to turn generators will slow the air. If the air is slowed, it makes the cars work harder to maintain speed. If the cars are working harder, they burn more fuel. See where this is headed?

Diablo Canyon and San Onofre, the two nuclear plants in California, each have two working nuclear reactors on site. Each one produces more than 1,000MW. Hmmm... let's figure out how many 5MW wind generators it takes to add up to just one nuclear reactor. Be sure to keep that picture of the 5MW variety of wind generator around for reference.

Then there's the issue of how much wind you can get in most areas.
Added to the fact that nuclear reactors and coal plants don't depend on (in)consistent wind patterns, daylight hours, or weather conditions.

How much does wind blow? http://windeis.anl.gov/guide/maps/images/wherewind 800.gif

Be sure to focus on the amount of area that rates above "good." Notice how some states are COMPLETELY screwed with regard to wind power. What? Have some states sell their power to the other states, the completely energy dependent ones? Look up how well that worked when Enron, a Texas company, held sway over the energy supply of a different state, California. Now imagine that happening to a state with less clout than California.

Solar and wind are not going to save us. They are excel

Only just before this mission (STS-118).

http://www.nasa.gov/mission_pages/shuttle/news/wir eless_scanner.html

Basically it's a close-range imager for cracks in the tiles, to reduce the need for manual inspection. Little detail in that link, but the question is: Was it was made for the ground crew or the shuttle crew to inspect the tiles?

Still, at least they have the SSPTS (Station-to-Shuttle Power Transfer System) available and working, which gives them a few more days in orbit to evaluate and fix things.

Lucky for you my young padawan I have no life.

Does anyone know how/if NASA handles things like micrometeorites?

Dunno exactly, how's that for a start? I do know the shuttle's glazings are replaced about once every 10 flights due to impact, mostly with man made stuff like paint chips from exploded satellites. Just guessing here and don't quote me, but the way they deal with this is probably with stats. As in, if a chip of paint can ding a window, I guess a gram-sized piece of debris can poke two holes in the orbiter (an in and an out). Although, that might not be fatal if it doesn't pass through someone's body, the little hole can probably be patched with, you know, the space shuttle hole patch kit they must have.

The Orbiter is maneuvered to avoid known space debris, but that only goes down to about tens of centimeters. So stuff smaller than that has to be handled with stats.

NASA doesn't exactly come across as a "crack" outfit anymore...

I understand why you might say that, but it's a little bit unfair to cast your net that wide.

At one time in my long and sorted career I participated in a NASA sponsored symposium on UBE engines. Have to admit, there was a rush to riding the bus that had NASA written on it, and I had a NASA badge. It was really something, just being associated with that acronym.

My point is, the young lads and lasses that work for NASA are just pumped to be there. Don't disparage them for feeling that way. It's the older bunch that should know right from wrong, and that's where you have a point, they don't always act like they do.

NASA has a unique problem engineering-wise, which is that the very name psyches out the people that work there. Anywhere else, a highly qualified young person would feel protected to call bullshit, but not at NASA.

If I could give any advice to a 20-something working at that place it would be: don't act like you work for a legendary establishment. Act like you work for ACME spaceships Inc. Call it like you see it, and if you find it hard to do think of this: if NASA turfs you out, there are plenty of opportunities for people with those 4 letters on their resume to make obscene amounts of money. So, theres absolutely no reason to worry about your future. Do the right thing.

I wonder how many times this kind of thing happened...

Lots (yes it's a pdf so kill me). See page 9.

Sorta reminds me of the time the de Havilland Comet blew up in mid air and aviation engineers learned about fatigue and decided to go look at other airplanes for signs of fatigue cracks and found them everywhere. Talk about freaking out.

Then, after that, several smart people[1] figured out that cracks always had been everywhere and, you know, chill. The airplanes we fly around on have lots of cracks. The thing that saves our collective butts is that they are understood.

Are you aware that the Tabular data that the dailytech article references that was "quietly" updated were for "Figure D: Annual Mean Temperature Change in the United States"? Note the word "CHANGE".

Which means that the difference in average temperatures in 1934 and the previous year was more than any other year on record, NOT that 1934 was the hottest year on average.

The article is incorrect in interpreting the data in the table. Yes, Figure D was updated, but that figure doesn't say anything about the absolute hottest average temperature... that would be Figure A... and the tabular data behind that figure http://data.giss.nasa.gov/gistemp/graphs/Fig.A.txt did not have its data updated and still indicates that 2005 is the hottest year on record.

You _can_ read right? http://data.giss.nasa.gov/gistemp/ Did you read the background
section? sheesh....