Here's the last day, Sunday, May 24, when they landed.  I will follow with one more set of final thoughts.

6am - the sky has large patches of blue; I begin to feel some optimism that they might actually land today.

We follow our usual routine, going through security and driving to the press site.  I'm not the only optimist; everyone seems buoyed by the improved weather, although there are still some clouds and thundershowers offshore.

The word is, one way or another, they're determined to land today.  The shuttle has one more day of supplies, so tomorrow could be an option, but they want to keep it as a last resort emergency day, in case they discover a problem as they're starting the landing prep.

The other possible landing site for Atlantis is Edwards Air Force base in California, the famous dry lakebed that was the setting for much of Tom Wolfe's book The Right Stuff.  Edwards is nearly ideal - it's got miles and miles of nothing, incredibly long runways, and usually excellent weather.

But NASA really would prefer to land at Cape Canaveral, for one simple reason: transporting the shuttle back here from Edwards is a real bear.  It costs about $1.8 million, and it's pretty dangerous to boot.

To transport the shuttle, they strap it on top of a special 747.  Because the shuttle's exterior is so vulnerable to impacts, they won't fly through rain or weather - that could damage the shuttle's surfaces.  Nor can they fly too fast either, also for fear of damaging the shuttle.

So they fly slow and low - below 10,000 feet, where the air is thickest.  Between all the weight they're carrying and the air resistance, they burn through fuel fast.  So they have to stop frequently; they end up doing a series of short hops from one military air base to another.  It takes about a week to fly the shuttle from the West Coast to Florida.

So it's pretty clear why they prefer to land here.  That's why they've tried three days in a row - despite picture perfect weather at Edwards.

By now, on our third day of waiting, our crew is running out of ways to pass the time.  Our sound man tells me a "producer joke:"  Q: How can you tell if a producer is lying?  A: When his lips are moving.

It occurs to me to counter with a "sound man" joke:  Q: How tall is the average sound man?  A:  I don't know, I've never seen one standing up.  (they always sit down on the job, get it?)  But since our sound man today is not only a nice guy, but also happens to be rather short, I refrain.

Instead, I answer with my personal favorite producer joke.  Q:  How many producers does it take to change a light bulb?  A:  I'm really not sure - what do you think?  I like this one because it points up one of the parts of the job that I think is hardest: maintaining objectivity or perspective.  Even though I do tend to have strong opinions, I'll often feel unsure because I'm just too close to a film...

Without warning, an announcement begins and our levity abruptly ceases.  Although the sky looks mostly blue, there are still some storm clouds on the edge of the general landing zone (a circle 30 miles in diameter centered on the runway).   The Weather Officer says the weather here is "too dynamic," meaning it changes often and fast.  Though it's good now, there's no guarantee what it will be like an hour from now.

Therefore, they're going to land at Edwards. 

A collective groan passes through the crowd.  After camping out here for three days, it's definitely a letdown.  A third of the crowd starts to slowly collect their stuff and drift out to their cars; the rest of us wait to watch the Edwards landing on TV.

I remind myself that the astronauts are kept pretty sequestered once they get back to earth; we'd be lucky to get a statement from them, or a short Q&A, but no real one-on-one interviews would be allowed anyway.

An hour later, we watch a beautiful touch down on TV.

They're back, and they're safe.  I'm relieved.

After spending two years filming them practice and prepare, it had started to feel like the actual flight might never happen.  And now, over these past two whirlwind weeks, it has.

I can't believe it's over.

We head for the airport and begin our own journey back home.  I've learned an enormous amount these past two weeks, and changed some long held opinions about the space program.  Tomorrow I'll jot down some final thoughts.

Concussion science has come a long way since the bad old days when head injuries were diagnosed by finger-counting. But a new study finds that minor league hockey players have trouble identifying basic concussion symptoms and don't know when its safe to get back out on the ice after a knock to the head.

That's a sobering thought to anyone who watched Chicago Blackhawk Martin Havlat lying glassy-eyed on the ice after taking a major thump during one of last week's NHL playoff games. Okay, maybe not so many people watched that (except for Canadians, Chicagoans, and Detroiters like me), but here's the kicker: Two days later, Havlat was back in the game. Not for long, though: After taking a fresh hit, he made his way off the ice and didn't come back.

Concussions aren't harmless, especially when they come in pairs. NOVA scienceNOW talked about the long-lasting and frustratingly nebulous symptoms of concussion in a story that aired last year. Even more disturbing are results from the Boston University School of Medicine, where researchers are studying the brain tissue of deceased NFL players. Many of these players were in their 30s and 40s when they died, but their brains were mottled with the same tangles neuropathologists expect to see in elderly dementia patients.

Before they died, the players had reported crippling depression, memory problems, uncontrollable emotions, and debilitating headaches. Is this what we envision for our sports heroes' golden years?

They continue to take it right up to the last minute before making their decision.

A little while before Scooter would fire the engines to start their descent - if they were going to land - we heard a command from Mission Control to the astronauts: "begin loading."

I make some inquiries, and it turns out that this refers to "fluid loading" - essentially drinking a bunch of water.  Apparently, astronauts in space tend to get dehydrated.  Returning to earth after nearly two weeks without gravity is tough on their bodies, and dehydration makes it worse.  Some returning astronauts have needed an IV to restore fluids before they can walk steadily out of the shuttle.

To counteract this, they must drink fluids right before they come down - a lot of fluids.  Sixty-four ounces of liquid, which I calculate is just slight less than an entire six-pack.

Now, approaching the second landing opportunity of this morning, I again hear the command: "Atlantis, begin loading."

Wow - they each drank nearly six 12-ounce glasses of water roughly an hour ago, and now they have to do it again.

Again, we assemble at 6:30, go through security, and enter Kennedy Space Center (KSC).  Again the sky is totally overcast; I'm not at all optimistic that they'll land today.

Proceeding from the security checkpoint toward the press site, I suddenly spot the Shuttle Training Aircraft above us and to the left, descending steeply.  Astronaut Steve Lindsay is flying mock shuttle landings in order to assess the conditions that Scooter Altman, Atlantis's commander, will experience if they do end up landing here today.

The Shuttle Training Aircraft is a Gulfstream jet that has been fitted with shuttle-type controls, and modified so as to handle like the shuttle.  Shuttle commanders and pilots (the ones who actually fly the shuttle, as opposed to the "mission specialist" astronauts who do spacewalks but no piloting) use this training airplane to practice landing the shuttle.

Scooter, Atlantis's commander, explained to me that the shuttle comes in 7-times steeper than an airliner.  Watching the training jet make a mock approach, it almost looks like a plane about to crash - it seems to be literally diving toward the ground.

On friday, we meet our camera and sound guys at 6:30am - and things don't look good.  The sky is totally overcast; I can't imagine they'll try to land in this.

By 8:30 we learn that the first opportunity is canceled; an hour later, so is the second.  The forecast doesn't really call for much to change, but nevertheless, they'll try again on Saturday.

I guess it's not so bad for the astronauts; for twelve days every minute of their time has been scheduled, broken down into five-minute increments.  John Grunsfeld, who has flown three previous shuttle missions, has told me that they are so busy in space they literally barely have a moment to look out the window.  Now they've got most of a day for sightseeing

Notes from Thursday's shoot:

With the spacewalks done and the shuttle safe to return, I'm dealing with loose ends and getting ready to travel to Florida for the landing, scheduled for tomorrow.

This morning cinematographer Joe Brunette and I left the hotel at 5 to go shoot the sunrise over Johnson Space Center.  Since the Goddard engineers on the Hubble repair team generally came on shift at 4am each day, for several days we've gotten up in the middle of the night to film them going to work.

Now we need establishing shots - bigger panoramas we can use to signify the passage of time in the film.  And nothing says "day over" or "new day begins" like a sunset or sunrise.

The problem is, Houston is as flat as a pancake, and we need a high vantage point.  We've spotted the perfect spot - the back yard of a Houston Fire Dept station next to NASA.  Their roof would be even better, perfect really, but we can't imagine they'd give us permission to go up there.

The station seems deserted; we walk in, calling out "Hello?  Anybody here?" and feeling somewhat like intruders.  Finally two suspicious firemen emerge from a back room with a definite "who the hell are you, and what are you doing in our house?" look.  "Can I help you?"

I begin my standard spiel: this is who we are, we're making a film about the Hubble mission for PBS, it's part of the series "Nova," we need to shoot the sunrise, we just want to place our camera here, we won't disrupt your routine or damage your property, I'll be happy to sign something, blah, blah, blah -- when fireman Rudy interrupts me: "I love Nova - how 'bout using our roof?"

Joe and I exchange glances; this is more than we had dared hope for.

Hi guys;
Landing postponed 2 days in a row -- tomorrow should be it, whether it's here in FL or out at Edwards Air Force base in CA will be decided at the very last moment.

I have gotten somewhat caught up on more blog posts. 

Wednesday 5/20 -- 2
Late in the day we got the word that the team scrutinizing video of the shuttle has pronounced it free of damage - so it's safe to return.

The whole subject of danger on this mission is a strange one.  Whenever I ask the astronauts about danger, I notice I speak in general terms, whereas they answer me in the language of mathematics and probability.  I tend to think of the danger as very dramatic and a big deal; they boil it down to numbers.  And they never say "danger" - they always call it "risk."

They trust experts to calculate the odds of disaster, which are expressed in a ratio like 1:200, or 1:160 (I have no idea how they arrive at these numbers).  Back in February, two satellites collided in orbit, greatly increasing increasing the amount of space debris.  That event also increased the chances of the shuttle getting destroyed during the Hubble repair mission.

Shortly after the satellite collision, Greg Johnson ("Ray Jay") the pilot, told me that the experts had recalculated the risk of "loss of crew and vehicle" due to getting hit by debris; the latest estimate was something like 1 in 160.  I was surprised; that sounded uncomfortably dangerous to me.

But to him, it was a number.  And mission planners were taking steps to change the number to make it more acceptable (I'm told they prefer to keep the risk around 1:200).  This is what they call "risk management" or "mitigating" the risk.

Hi guys;
Well, the weather forced a postponement of today's landing.  It doesn't look too good for tomorrow either; they may end up landing at Edwards Air Force base in CA.

The good part was that it has given me some time to do more writing. Here are my thoughts from Wednesday.

With all the spacewalks complete and 100% successful, and Hubble once again released into its own orbit, there's a sense of the mission starting to wind down.  And for the Goddard engineers and many of the Hubble repair team on the ground it is.  But they're just part of an even larger team, which deals with launching, flying, and landing the shuttle.  Repairs over, that team is now shifting gears; the focus now changes to getting their seven friends in space safely back on the ground.

It's not getting much attention, but at this very moment the rescue shuttle Endeavour is on the launch pad in Cape Canaveral just days away from being ready to launch.  It normally takes weeks and a cast of thousands to get a shuttle prepped and off the ground, so to save time the rescue mission has been proceeding as if they're going to go.  We're told they won't cancel Endeavour's countdown until Atlantis has actually fired its engines and started for home.

Sorry -- I fell behind in my updates these past few days.  My recent evenings have been spent shooting sunsets and nighttime exteriors at NASA, plus some very early morning sunrises.  So I haven't had much writing time since Monday.

I flew to Cape Canaveral today; they're supposed to try and land tomorrow morning.  But the weather here is bad, so they'll probably postpone the landing a day.  If so, I'll try to catch up on my updates over the next couple of days.

Here are my  notes from Tuesday:

This morning Megan McArthur, the only woman on the crew, released Hubble back into its own orbit - the last time humans will ever see it in person.  The astronauts have been joking about who has the honor of being the "last person to touch Hubble."  It seems like it was John Grunsfeld at the end of yesterday's spacewalk - but technically it was actually Megan, since she was operating the robotic arm that released Hubble today.

Throughout our two years of following these folks, every time I've asked her about her worst stress or anxiety, Megan has consistently articulated the same answer: "breaking Hubble."  The robotic arm she operates is huge and powerful, and in her work there is enormous potential for one false move to damage the telescope.

It's not often you find the label 'Viewer discretion advised' accompanying a science talk. But that is what this Ted Talk by author Mary Roach warns. And for good reason. In her talk, Roach, bestselling author of 'Stiff' and 'Bonk,' shows a highly disturbing movie of a pig farmer inseminating and 'manually stimulating' a female pig to improve its litter numbers.


Framegrab from TED

Aside from the cringe-worthy film, the talk is actually quite interesting. But for all the crazy experiments that have been done over the years to examine orgasms, we still have no clue what evolutionary purpose the behavior serves in us. So although I'm still not sure why it's 'good for me,' I do know why it's good for a pig.

It's the last spacewalk of the last mission to Hubble. I'm pretty sure it's also John Grunsfeld's last spacewalk of his long career, and probably his last space mission ever.

True to form, Grunsfeld is pushing hard for managers to let him add to today's tasks the insulation blanket replacement that they had to skip yesterday (because fixing the STIS instrument went so extra long).

Last night we got a rare glimpse of some negotiating (or "horse trading," as our sound man put it) between ground controllers and the astronauts. They were trying to decide how to revise today's spacewalk agenda, and how hard to push to add yesterday's skipped item (the insulation blanket) to today.

We heard them go back and forth: Grunsfeld was saying, in effect, "I want to try it," and the ground was basically saying "we'll see." I was thinking that in the end, the astronauts are the ones up there, and I wondered how hard Grunsfeld would actually force the issue.

After a long delay involving breaking off the handle that wouldn't budge, and then finding his power tool was dead and having to go retrieve a spare tool, Massimino was behind by two hours, but finally everything was working.

He began removing the 111 screws, inserting his power screwdriver through one hole at a time in the Fastener Capture Plate (FCP). He really zipped through the process, making great time.

Once he got them all loose, he gingerly removed the FCP and--voila! Everyone's eyes are glued to the monitor, looking for any sign of screws drifting loose. But not a single one escaped--the contraption worked exactly as planned.

Well they finally got the doors closed. Today has seen an amazing turnaround; every day they make a list of every single little thing that is at all less than "perfect," down to the tiniest little detail. Usually these lists have many dozens of items; today's list literally had only two.

The morale change has been tangible. Last night people were really worried about today. The thinking was along the lines of "two spacewalks that were supposed to be routine turned out to be really quite difficult; today's is supposed to be extremely difficult at best, so what will happen? Do we even have a chance of success?"

Then the amazing happened--everything went nearly perfectly. The work Grunsfeld did truly set a historical precedent, and he actually got ahead of schedule. Everyone is thrilled and amazed; the scientists here are ecstatic.

However--there are two more spacewalks to go, with lots of critically important work left. Tomorrow is another repair like today's, trying to fix a spectroscope which, like today, involves removing lots of tiny screws and trapping them in the process.

I'm wondering whether today's momentum shift will hold, or whether they'll once again hit a wall of problems. We'll see!

Well, Hubble continues to surprise. The hardest job of the mission, repairing the Advanced Camera for Surveys (ACS), has gone amazingly well.

Working in extremely tight quarters, around a corner from his work site and partially out of view, John Grunsfeld has managed to complete the first actual instrument repair ever done in space.

First he cut through a metal grid and removed it, avoiding the sharp edges, and exposed a cover plate held on by 32 tiny screws. Next he partially loosened all the screws, then installed the Fastener Capture Plate, then removed all the screws.

After two years of worry, amazingly not a single screw stuck, or broke, or was stripped. And, captured inside the special tool, nothing floated loose inside Hubble where it could have damaged the telescope.

Spacewalk #3 is today, which everyone has been saying for months will be the toughest.

The first two were "supposed" to be somewhat routine, but proved to be fairly difficult. So far, two unexpectedly hard days, both of which had problems and went long. Yesterday was one of the longest spacewalks on record (nearly eight hours; they plan on 6:30 and prefer not to exceed that for reasons of fatigue, health, and falling behind schedule from day to day).

First half of today is removing "Costar," the corrective lens originally installed in 1993 to fix Hubble's blurry vision. They now have it out without incident. Next step is to install a new science instrument, the Cosmic Origins Spectrograph, in its place. That's expected to be routine, but the way things have been going, who knows?

Second half of today is the nail-biter: repairing ACS, the Advanced Camera for Surveys. Grunsfeld will be trying to remove 32 tiny screws, then pull out four circuit boards, while working mostly blind.

They're now 1:45 into the spacewalk; it promises to be a very long day.

Spacewalk #2 is in progress.

Highest priority is to replace three Rate Sensor Units, which contain spinning gyroscopes that are used to point Hubble and keep it stable. Because the gyros constantly spin at 1,000s of revs per minute, they wear out (these have been in Hubble since 1999).

On this mission, they have brought a new improved design. Two of three went in okay--problem on the third. It does not seat properly.

They've tried it in two different locations without success. Next they abandoned the improved version, and went to a spare unit they have (one of the original design, removed from Hubble in 1999 and reconditioned).

It, too, has been unable to go in properly, but on the final attempt it just worked.

So they have now successfully replaced all Hubble's gyros, but because of the problems they are at least one hour behind on their spacewalk. Yesterday went long as well, but management allowed them to stay outside late. Today they'll probably have to get that permission again.

Their next task is to replace batteries, which should be easier.

They just got out of an almost big problem.

Their first big task on spacewalk #1 is to replace the Wide Field Camera 2, Hubble's main camera that has taken many of the famous images. It's held in by one big bolt, which refused to loosen on repeated attempts.

The next step was to apply more force at the risk of breaking the bolt (if the bolt breaks, the old Wide Field would stay in and the expensive new camera comes back to Earth without ever being installed--a huge disappointment).

On the final attempt, the bolt finally loosened.

In the end, the new Wide Field Camera 3 was successfully installed. But a job that was supposed to be routine turned out to be a real nail-biter, and the first spacewalk ran long.

No one is saying so out loud, but the feeling I sense here is that this is not a good omen for the start of the mission. But then again, engineers don't believe in omens.

Still, a day that no one expected to be troublesome turned out to be highly problematic and marked by an extremely tense close call. Hubble Program scientist Dave Leckrone said he aged five years during today's spacewalk.

Tomorrow is supposed to be "routine" (just like today was???) although the most important task--replacing Hubble's gyros, used to stabilize the telescope--is known to be "challenging" (astronaut-speak for damn difficult).

We're trying to catch up with Neil deGrasse Tyson, who we know is here to see the launch. The problem is, Neil is a VIP, and the VIP group has their own badges, their own escort, and their own agenda.

We have set up a general plan, but I'm basically reduced to waiting and trying to spot him among the thousand or so people milling around. We have three hours before launch; I fill the time walking circuits through the crowd, scanning for Neil. I feel like a celebrity stalker...

Then I get word: he's here! I get to where he is, and find him surrounded by folks wanting his attention. We manage a quick hello, then he's off to do a live webcast; I'll get him for ten minutes when that's done.

We were out at the launch pad yesterday, and the shuttle seemed huge. But from where we are today it looks impossibly tiny. We're three miles away; no one is allowed any closer.

We have about three hours until launch. I'm concerned about our visibility; there's a tree line at the horizon that blocks the lower half of the shuttle from view.

I meet a CBS News producer, and ask if we can have some space on the roof of their building; he's a fan of Nova, and he graciously agrees. My Dad worked for CBS for nearly thirty years, and I'm thinking if he were alive today, how cool he would think it is for me to be on the CBS rooftop - perhaps Walter Cronkite covered launches from here, I don't know...

In 16 years, producing or coproducing five documentary films on space, 11 hours of programming in total, I've never seen a single space launch in person. I've constructed "launch scenes" in films many times, but today will be my first experienced for real.

"There's excitement in the air here" might be a clichéd phrase, but at Cape Canaveral this morning it seems perfectly apt. There are many hundreds of people milling around in the Public Affairs building, probably thousands in total spread across the grass at the site. The place is buzzing.

The giant digital countdown clock is on the lawn in front of us, and scores of live broadcast and webcast booths are set up in tents. Some of the old guard (CBS, NBC) have air-conditioned permanent cinderblock buildings (which from the looks of them must date back to the early years of the Space Race and Apollo launches).

I've seen all this before, in old film footage from the Apollo years or watching shuttle launches on TV--but to actually be here feels very different.

For one thing, after working for two years following the astronauts and engineers conducting this mission, filming them and spending time together, I know the people who will be sitting on top of the rocket. I'm acutely aware of the danger involved, and it's not a good feeling; I'm actually pretty nervous.

Jets and helicopters are patrolling the air space around the launch site, and their noise overhead contributes to the sense of nervous energy.

Now we're off to board buses to see the astronauts walk out--basically a photo op before they board the shuttle. First we have to get all our bags, cameras, and gear "sniffed" by an explosives-sniffing dog.

It's extremely hot--in the mid-90s--and I'm sweating bullets. For some reason, the dog seems oblivious to the heat.

Is rap the ideal medium for spreading scientific knowledge? You be the judge:

If you've been following this blog religiously (as I'm sure you have been), you may have read one of our previous posts about naming a fungus after President Obama, or the one about the attempt to name a piece of the space station after Stephen Colbert.

Well it looks like Colbert will finally get his name claim to fame and - it could be argued - that it's way cooler than a presidential fungus.

Two entomologists took on Colbert's challenge to the science community to "name something cooler than a spider" after him to honor him. So the scientists named a beetle after him. And to let Colbert know about it, they sent him a picture of the bug along with a birthday card asking 'What has six legs and is way cooler than a spider?' The answer, of course is the newly discovered diving beetle from Venezuela, Agaporomorphus colberti.

It's nice to see scientists with a sense of humor similar to Stephen Colbert's.

Like music? Hate invasive species? Bret Shaw has some tunes for you.

Shaw, an environmental communication specialist, teamed up with three singer/songwriters to make rockin' instructional music about preventing the spread of aquatic invasive species. (Invasive species can travel from lake to lake on contaminated boats, bait, and bilge. I don't know what bilge is but it definitely sounds like something that should be properly drained.)

There's The Ballad of Aquatic Invasive Species, the rockabilly-inspired Clean Boats, Clean Waters, and my personal favorite, One Bait, One Lake.

Take a listen...and then take comfort knowing that, when they're not singing about draining bilge tanks and Viral Hemorrhagic Septicemia, these guys all have day jobs.

Okay, college students, here's a simple way to freak out all of your classmates:

1. Buy a label-maker
2. Print out a bunch of labels that say "GERMS"
3. Stick them on every door handle on campus

I don't suggest you actually try this (unless, say, you own stock in antibacterial soap), and I can't take credit for the idea, either: I was actually a victim of this stunt back in my Bright College Years. I don't think I've ever washed my hands so many times in a 24-hour period.