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Lucky or Smart

August 21, 2007 4:31 PM

NASA, given heavily to acronyms, even has one for death: LOCV. It actually stands for Loss Of Crew/Vehicle, and there were passing references to it as mission managers debated what to do about that now-famed gouge mark beneath Endeavour's tail.

Early on, John Shannon, the deputy shuttle program manager, made it clear he'd be more concerned "if we were in a Loss Of Crew/Vehicle situation." They decided shuttles had survived worse tile damage--they had "a rich history" of it, he said--but they worked the problem for nearly a week. Inch-deep holes rarely receive as much attention.

Now Endeavour is safely on the ground in Florida, and we've had our first look at the spot after the heat of re-entry. I'll leave it to others to decide if NASA was more lucky than smart. Your thoughts on that--or other matters technological or scientific--are, as always, welcome.

With STS-118 over, I'm going to take some vacation. I hope you're getting some time for rest too. See you after Labor Day.

August 21, 2007 | Permalink | User Comments (7) | TrackBack (0)

The Storm Below

August 17, 2007 4:11 PM

The shuttle story has been going on for a week now, and it's not over, but here are a few last notes for now:

1) A fair number of you have questioned NASA's decision not to order a spacewalk to fix that damaged tiling; here's some insight into what may have been on engineers' minds.  Todd Halvorsen of Florida Today has posted a report done in May by Christine Stewart of Science Applications International Corp., a NASA contractor, titled "EVA Hazards Due to TPS Inspection and Repair."  (Acronym alert: EVA is Extra Vehicular Activity, or spacewalking; TPS is the shuttle's Thermal Protection System, or heat-shield tiles.) 

The report lays out the risks that a spacewalking astronaut in an EMU--sorry, Extravehicular Mobility Unit, or space suit--could face or cause.  Included on the list: sharp corners that can cut a suit open, high temperatures, electric shocks, toxic fuels, and, well, clumsiness.  "Collision of the EMU, particularly the helmet, could result in damage to the Orbiter TPS beyond that which was already present."  The full document is HERE. 

2) If you wish they'd patched that spot, and the the idea of waiting until Wednesday's scheduled landing makes you uneasy, then keep an eye on Hurricane Dean.  NASA's concerned that the storm may be threatening Houston by then, forcing controllers to evacuate, so it's floating the option of bringing the shuttle home on Tuesday. 

Lead Flight Director Matt Abbott, in a briefing this afternoon, said, "This business that we're in, flying in space, this is what we do all the time, and sometimes we make it look really, really easy, and it's a really, really difficult thing to get these vehicles up in space and keep our friends and colleagues safe up there and get them home safely."

August 17, 2007 | Permalink | User Comments (3) | TrackBack (0)

NASA Shuttle Decision: No Repair Needed

August 16, 2007 10:57 PM

NASA managers have told the crew of Endeavour that no repairs are needed after all to the underside of the shuttle. 

Pictures had shown a three-inch-wide, inch-deep gouge in two heat-shield tiles after launch, and the shuttle's Mission Management Team had debated for nearly a week whether to send astronauts on a space walk to patch it up.

But after a final five-hour meeting, MMT chair John Shannon said he polled the teams of engineers working on the issue--more than 200 people at NASA centers around the country were involved--and they came back with "a unanimous recommendation that the damage was not a threat to crew safety."

Shannon said there was some disagreement, though, over whether to make a repair anyhow; an engineering group in Houston thought it would be, in Shannon's word, "prudent" to send astronauts out to fill the damaged spot with a sealant material. 

Such a spacewalk would carry risks of its own--an astronaut might accidentally hit other tiles and do more harm than good--but the dissenters told Shannon "they could not see a reason that that could cause additional damage to the orbiter."

So, Shannon said, "It was not unanimous but it was pretty overwhelming not to do the EVA."

The Endeavour astronauts were told of the decision shortly before they were supposed to go to sleep.  "It's great we finally have a decision and we can press forward," said mission control.

"Tell everyone thanks for the hard work," replied the shuttle's commander, Scott Kelly.

One consideration: engineers knew the shape of the existing gouge pretty well, said Shannon, and had tested how it would be affected by heated air rushing past it on re-entry.  The same could not have been said for a spot partially filled in by an astronaut with sealant material.

"You have something you know you can live with; why would you take the risk of doing the EVA to change that cavity into what could potentially be an even better situation but also could potentially be a worse situation?" Shannon asked.

"If we had a situation that I thought was a threat to crew safety," he said, "I would go do that EVA and feel good about it."

There will still be a spacewalk on Saturday, according to current plans--but it will be routine work on the space station to get it ready for new parts to be delivered by the next shuttle mission.

August 16, 2007 | Permalink | User Comments (26) | TrackBack (0)

Thumbs Up

August 16, 2007 6:54 PM

A little late to be terribly useful, here is a closeup of the damage Wednesday to Rick Mastracchio's spacesuit glove. 

And here's a LINK to a picture of some shuttle tiles on the ground after an experiment to see what would happen if Endeavour re-entered without any repair to the damage on its underside. 

In essence, the tiles were placed in a chamber and exposed to re-entry temperatures and airspeeds.  (Just to be clear, the picture is NOT a new shot of the tiles on Endeavour.)  MMT chair John Shannon said that at hypersonic speeds, the outer layers of tile would be peeled back--the gash would get larger--but with air rushing past, the temperature of the aluminum beneath would only be 40 degrees F. higher than it would be if there were no gouge. 

There's more HERE from AP.

August 16, 2007 | Permalink | User Comments (1) | TrackBack (0)

Torn Glove

August 15, 2007 4:36 PM

NASA just gave a quick, inadvertent illustration of why it's not a slam-dunk decision to send astronauts on a spacewalk to go fix the gouge in the shuttle's underside.

Astronauts Rick Mastracchio and Clay Anderson were outside, configuring components of the space station, when Mastracchio noticed he had cut through one of the outer layers of his left glove. 

The cut was in the left thumb.  Mastracchio was told, as a precaution, to go back to the station's airlock, so that they could repressurize quickly if his suit began to leak oxygen.  Anderson was told to come back in as well.  The men were about five hours into a six-hour EVA, and were running ahead of schedule, so they had finished most of the work planned for them.

"The gloves were good. I don't know where this hole came from," Mastracchio told controllers in Houston.

Since the end of the EVA, Mastracchio has reported "a couple of little pinholes" in the Vectran layer of his right glove as well.

The gloves have five layers.  The outermost is a laminated cover over some parts for thermal protection, and the second, made of a synthetic polymer called Vectran, protects against cuts and scuffs.  That's what was damaged.

Beneath that is a layer of nylon, and then a layer of rubber that actually keeps air inside the suit.  Finally, there's a fabric liner so that the astronaut's skin doesn't rub against the rubber bladder layer.

Vectran, used for all sorts of things from parachute cords to helicopter rescue cables, makes for a protective glove, but also a clumsy one.  NASA's been trying to come up with a more comfortable design for years, and recently held a contest to invite ideas from the public.

Another astronaut, Robert Curbeam, found a cut in the Vectran layer of his glove after he came in from a spacewalk last December.  Since then, astronauts have been told to check their gloves every half hour during a spacewalk.

How does this figure into whether to fill in the gouge in that heat-shield tile?  It's a reminder that spacewalks carry their own risks.  The greater one is that an astronaut, in that big, clumsy suit, might bang against other tiles on the way to fixing the one in which they were interested.  See our interview with astronaut Piers Sellers, posted earlier today.

NASA's John Shannon made it sound like they felt pretty satisfied that a tile repair would not be necessary--one test suggested that the air swirling into the gouge would not reach a temperature of 350 degrees F.  Aluminum, a little of which is exposed, melts at 1,200 degrees at sea level.  But they wanted to see one more test result, and at last word, we were told not to expect a decision today.

(NASA Photo: Astronaut Robert Curbeam in December, during a space walk on the STS-116 mission.)

August 15, 2007 | Permalink | User Comments (2) | TrackBack (0)

Twenty Questions

August 14, 2007 1:42 PM

Amid all the business over the shuttle's tiles, life really does go on.  Barbara Morgan, the teacher turned astronaut, took questions today from schoolchildren at the Discovery Center of Idaho in Boise, about two hours from McCall, where she used to teach.  She was joined by three fellow astronauts, Al Drew and Dave Williams, and Clay Anderson of the Space Station crew.  It was actually quite a bit of fun to watch, and we'll post a video clip on our Technology & Science Page.

Even for an educational event, NASA doesn't like surprises.  Kids' questions to the astronauts were submitted in advance, and included in the execute summary for the day.  It also gave the astronauts a chance to arrange for appropriate props.  (You can click HERE for the summaries: see Flight Day 6, and go to page 19 of the 28-page PDF for the questions.)  Here are the questions:

1. If you threw a baseball in space, how fast would it go?

2. When you were a kid, did you ever think about becoming an astronaut?

3. What is it like when you first enter space and you are weightless?

4. What types of exercise equipment and regimen are you using to prevent bone loss?

5. If you had an extra day in space, how would you use it?

6. What would you have to do to prepare for a space walk (EVA)?

7. How does the crew get clean air in the shuttle?

8. How does being a teacher relate with being an astronaut on this mission?

9. Could you demonstrate how you drink in space?

10. Can you see the effects of global warming from space?

11. Does the sun's head cause any problems during an EVA?

12. What is the most challenging part about manipulating the robotic arm?

13. What do stars look like from where you are?

14. Can you see the earth rotate when you are orbiting?

15. What are your responsibilities for this mission?

16. How did you train to prepare for microgravity?

17. What was the hardest thing you had to accomplish to prepare for this mission?

18. What was the most interesting aspect of going through the astronaut training?

19. How do you prepare to go into space?

20. How were you selected to do a spacewalk?

Please bring your answers to the front of the classroom after the quiz.

August 14, 2007 | Permalink | User Comments (3) | TrackBack (0)

Shuttle Damage More Serious Than First Thought

August 12, 2007 9:16 PM

It turns out, says NASA, that the three-inch ding in Endeavour's underside is deep enough to go through the thermal tiles to the aluminum skin of the orbiter itself.  It is hardly doom for the mission, or for the shuttle program overall, but it's an extra bit of trouble for both.

You can click on the picture to enlarge.  For perspective, this spot is near the door for the shuttle's right-side landing gear.  The tiles are six inches on a side.

The shuttle crew spent several hours on Sunday afternoon looking over the tiles with a laser rangefinder on a boom attached to the shuttle's robotic arm.  Until they'd done that, they had no sense of the depth of the damage they'd spotted on Friday afternoon as the shuttle docked with the space station.  (See previous post HERE.) 

John Shannon, who heads the Mission Management Team for shuttle flights, says they were prepared for this.  "We have  spent a lot of money in the program and a lot of time and a lot of people's efforts to be ready to handle exactly this case." 

More from NASA is HERE.  It's worth noting that their headline Sunday night was, "Managers Add Three Days to Shuttle Mission."  Endeavour is drawing power from the space station's solar panels instead of its own fuel cells for the first time, so it can stay longer. 

Which gives managers more time to decide whether to send spacewalkers out to go repair the hole; since the Columbia accident in 2003, they've devised various ways of covering it with sealant, or screwing a protective plate over it. 

They have to decide if astronauts, in their clumsy suits, run a risk of doing more harm than good, though.  The hole is not in as sensitive a place as the one that's believed to have led to Columbia's destruction. 

But there will probably be a new round of talk about whether shuttles ought to be launching with the built-in weaknesses that come from having a big fuel tank, full of super cold liquid hydrogen and liquid oxygen, that sheds foam or ice on ascent.  (There's a lot of background detail HERE.)  The bracket from which the suspect foam came this time is one that NASA knew was a known problem; a redesigned version won't be ready until next year.   

This flight is designated STS-118.  They want to get to STS-133, give or take a few flights, then move on.   

=======

(Note, added Monday afternoon: I've changed the headline of this post.  It had used the word "hole" to describe whatever it is on Endeavour's underside, but that seemed to set off a bit of a semantic debate.  John Shannon at NASA has used the word "divot.")

August 12, 2007 | Permalink | User Comments (6) | TrackBack (0)

Shuttle Has Damaged Tile

August 10, 2007 7:18 PM

About 58 seconds after liftoff on Wednesday, NASA says there was something, possibly a small piece of ice, that hit the belly of the shuttle Endeavour. 

And now, from pictures taken by the space station crew, they can see a spot, a couple of inches long, where it looks as if a heat shield tile has been damaged. 

How serious might this be?  John Shannon, the head of the Mission Management Team in Houston, says he would not venture to guess.  But he says shuttles have landed in the past with entire tiles missing.  They'll take a closer look with the shuttle's robot arm on Sunday, then decide if spacewalkers need to fix it.

Click on the picture to enlarge.  The issue is the white spot near the left edge of the image.  There are other, wider pictures HERE. 

What to make of it?  The spot is a few inches wide, but there's no saying whether it's at all deep.  The pictures were taken by space station crew members during that slow back flip the shuttle routinely does now before docking, and they're two-dimensional.  Sunday's look-see will be done with a laser rangefinder, during time already set aside for just such inspections.

When we know more, we'll pass it on.

August 10, 2007 | Permalink | User Comments (7) | TrackBack (0)

Watching the Shuttle

August 10, 2007 12:40 PM

This afternoon the Shuttle Endeavour closed in on the Space Station.  The the pictures were quite cool, and it's all on your computer.

NASA TV has a page HERE, from which you can watch live video of the mission (or anything else NASA broadcasts) in your choice of players. 

And NASA's Human Space Flight section shows where the shuttle and station are in orbit on a map HERE. An apology in advance on both of these: they can get overloaded when things are busy.   

The Mission Management Team reported yesterday that the launch was clean.  They count nine pieces of foam that came off the orange external tank, and say they believe three of them hit the orbiter, but they say they're not terribly concerned about them.   The astronauts are photographing the shuttle's wings and underside now as a matter of course.

The first foam hit was 24 seconds after launch, and bumped against Endeavour's rear body flap--the horizontal fin just beneath the three main engines.  The second, just under a minute into flight, did hit the shuttle's right wing, but does not appear to have done any harm either.  The last was nearly three minutes after launch, when the shuttle is high enough--and the air is thin enough--that a loose piece of debris doesn't get slowed by the air around it. 

All this may sound like rationalizing, but it's genuinely different from what happened in the case of Columbia in 2003--when the shuttle apparently flew its entire mission with a hole in the wing, while a few engineers fretted over the possibility of trouble, managers said there was nothing to worry about...and nobody had a way to look.

August 10, 2007 | Permalink | User Comments (1) | TrackBack (0)

Hurricane Forecast

August 09, 2007 11:30 AM

Don't be lulled, says NOAA.  This morning it updated its hurricane outlook for this year, and basically stuck to its guns, giving much the same numbers it had in May.

The summary is HERE.  It predicts: 

--13-16 named storms (down from 13-17)
--7-9 of those are likely to be hurricanes, with winds over 75 miles an hour (the May number was 7-10)
--3-5 "major" hurricanes--Category 3 or higher on the Saffir-Simpson Scale, with winds over 110 miles an hour.

Gerry Bell, the lead hurricane forecaster at NOAA's Climate Prediction Center, cites three reasons to believe the season is still likely to be an active one:

--Since 1995 we've been in the active part of the "Multi-Decadal Cycle" that typically lasts 25-40 years.  During these periods, winds and temperatures favor storm formation.  Since 1995, 9 of 12 hurricane seasons have been above average.
--The tropical Atlantic and Caribbean are both warmer than normal, providing fuel for storms.
--There appears to be a decent chance that a La Nina will form in the Pacific.  You'll recall that a La Nina--the opposite of an El Nino--is a giant stripe of cooler-than-average water along the equator in the Pacific.  It tends to rearrange the jet streams blowing over it.  An El Nino tends to steer the jet streams southward as they reach the Atlantic--shearing the tops off of some hurricanes that would otherwise hit the U.S. coast.  In the case of a La Nina, no such luck.

"This combination is known to produce very active seasons," said Bell in a teleconference a little while ago.

How can this be, when the season's been so quiet so far?  One graph that's useful is HERE, showing that early storms--June to mid-August--are really very rare.  There have been three named storms in the Atlantic so far this year; NOAA says there are typically two.  The peak of the season is still a month away, in mid-September. 

Bell cautions that all they're offering is a forecast of prevailing conditions for this year, and giving the number of storms that tend to form in similar years.  They cannot say when or where specific storms might yet be, though Bell says that in years that looked like this one, there have, on average, been 2-4 storms that made landfall in the U.S.

========================

Added Note:

To Wes, Chuck, Andy, and all others who may pass this way--it's great to hear your voices...or see your posts...or whatever.

Wes and Chuck asked for more about the Atlantic Multidecadal Oscillation, which seems to be a major factor in the number of hurricanes each year, and I'm happy to oblige.  NOAA's Atlantic Oceanographic and Meteorological Laboratory has done a helpful Q&A on it, which you can find HERE.

Nobody can say how long the "warm" phase of the cycle lasts; the best estimate is 25-40 years, which means that if the current phase began in 1995, it has another 15-30 years to go.  The last "cold period," when there were consistently fewer hurricanes, seems to have run through the 1970s and 80s, though it was only in the 1990s that meteorologists really caught on to it. 

Andy, I'm not in the least worried about hurricanes.  I'm totally freaked out about those colliding galaxies. 

August 9, 2007 | Permalink | User Comments (9) | TrackBack (0)

Galaxies in Collision

August 07, 2007 2:02 PM

Five billion light-years away, the Spitzer infrared Space Telescope has spotted a cataclysm in progress--four galaxies crashing into each other, flinging stars in all different directions. 

Galactic collisions are actually fairly common, but not on the scale observed in this case.  "When this merger is complete, this will be one of the biggest galaxies in the universe," writes Kenneth Rines of the Harvard-Smithsonian Center for Astrophysics.  More HERE.

Rines reports the find along with Rose Finn of Siena College and Alexey Viklinin of Harvard.  The abstract of their paper, which is being published in Astrophysical Journal Letters, is HERE. 

The picture above (click to enlarge) is an artist's conception, by Tim Pyle, of what the galaxies would look like from a hypothetical planet, circling a star that had been flung into intergalactic space as the galaxies came together. 

The Spitzer Telescope image has been combined with one in visible light from a telescope at Kitt Peak Observatory near Tucson Ariz., to form an image you can find HERE. 

Galaxies, consisting mostly of stars separated by empty space, do not actually "collide" with each other; they actually pass through each other, with the gravity from all those stars pulling them together into larger and larger galaxies.  Hence the astrophysicist's term, "merger."  Our Milky Way will merge with the Andromeda Galaxy in about five billion years, by which time science fiction writers predict we'll either have turned to dust, come to rule the universe, or something in  between. 

(Image credit: NASA/JPL-Caltech/T. Pyle (SSC))

August 7, 2007 | Permalink | User Comments (28) | TrackBack (0)

The American Infrastructure

August 02, 2007 11:20 AM

In the aftermath of last night's bridge collapse in Minneapolis, a lot of Americans may well have driven to work today wondering how things are where they live.

The American Society of Civil Engineers has raised the question in regular "report cards," the latest of them in 2005.  They gave America's bridges a grade of C, saying it would cost "$9.4 billion a year for 20 years to eliminate all bridge deficiencies." There's more HERE.   

The ASCE says there are 590,750 bridges in the country, and as of their last summary, 27.1 percent of them were "structurally deficient or functionally obsolete."

They worried more, though, about other parts of America's infrastructure--they gave grades of D-minus to drinking water, navigable waterways, and wastewater treatment systems. 

The Center for Strategic and International Studies has has its own commission; more HERE.

So there's plenty of worry to go around.  Is enough being done?   What concerns you?

August 2, 2007 | Permalink | User Comments (16) | TrackBack (0)

Swimming With Sharks

August 01, 2007 6:01 PM

One of the nice things about science reporting is that one gets to meet interesting people, doing worthwhile things, who want to tell their stories.

So yesterday, we met Bertha.

Bertha is a sand tiger shark.  She lives at the New York Aquarium, and Hans Walters, the man in charge there, is sure she's lived longer in captivity than any other shark in the world. 

This is more than a point of pride for one aquarium.  Fascinated as people seem to be with these top predators of the ocean, there's very little data on what their lifespans are.

"Bertha’s going to tell us how long these guys live," said Walters when we did our interview next to Bertha's tank.   "I don’t think anybody has come up with any hard evidence on how long sharks live. Well, Bertha, who came here as a  pup in 1965, is now 42, so she’ll show us.  As long as we have her, we’ll know."

It happens to be "Shark Week" at the Discovery Channel, and I was asked to see if there was some interesting science  we could add to an already-interesting subject.  Some items that came up:

--Sharks, of the superorder Selachimorpha, have been around for about 450 million years. 

--There are about 350 different species, most of them less than three feet long as adults.

--Like many other fish, many shark species have a sixth sense: they can pick up the minute electrical charges generated by the body of a fish a few feet away.  Very useful, along with their exquisite hearing, eyesight and sense of smell, for homing in on prey.

The behemoths made famous by the movies are relatively recent.  Until the end of the Cretaceous Period (the last of the dinosaurs), the top aquatic predators were probably marine reptiles, and only when they disappeared was there a niche for large sharks. 

Biologists regard modern sharks as an evolutionary success story.  They're very efficient in the water, they don't waste a lot of energy, and they've adapted to changing conditions.  Among the many places to look are HERE and HERE. 

Why are there a gazillion shark sites on the web?  That probably has more to do with human psychology than shark physiology.  (One good laugh: I searched for "SHARK" in capital letters, found, among other things, a Wikipedia entry on software encryption.  Try lowercase.)

I asked Hans Walters about his own interest.  "What do little boys like?" he said.  "They like fast cars, motorcycles, big dangerous things.  Dinosaurs, large predators, sharks.  I’m the little kid that never grew up."

Oh, one last thing that bears repeating: We were reminded by several scientists that worldwide, sharks attack human beings fewer than a hundred times a year.

August 1, 2007 | Permalink | User Comments (4) | TrackBack (0)