As a kid, I lived through several turning points for America, events that had a real impact on history: the beginning of the Space Race, the Cuban Missile Crisis, the escalation in Vietnam. It was hard to appreciate their uniqueness at the time, but one nice thing about getting older is that you have enough perspective to recognize a "historic moment" as it's happening--you can reflect on it in the present. So it is now with the final flight of the space shuttle.

Although American astronauts will still go into orbit, they'll have to hitch a ride with the Russians. We're outsourcing human spaceflight, which is somewhat ironic given that it was our fear and distrust of the Russians that got America into space in the first place.

I've always believed that exploring space is something worth doing, so I'm ambivalent about this. Certainly the shuttle has plenty of negatives: it's expensive and inherently dangerous. That's why the Columbia Accident Investigation Board recommended that it should not keep flying indefinitely.

There's also the question of its larger purpose. The shuttle can't explore new frontiers and distant worlds; it's a taxi, an SUV for moving people and stuff to low earth orbit.

I think that's why I never really felt passionately about the shuttle. I grew up watching Mercury, Gemini, and Apollo launches. Each seemed to do a bit more, go a bit farther--an inspired, and inspiring, steady progression toward eventually landing on the Moon.

The Moon--what a goal! Bold, daring, ambitious. Who cared what politics originally motivated it? For the first time ever, someone would leave our planet and journey to another world. The endeavor seemed noble, and the vast distances and extreme difficulties lent it a monumental scale.

And no part of Apollo seemed as monumental as the Saturn V moon rocket. Weighing thousands of tons, it would rise off the earth and propel three men to a speed of seven miles per second. Everything about it defied the imagination: too big for any road, its stages had to be moved by barge...the building to assemble it was so cavernous it had its own weather inside...the giant crawler that moved it could carry it miles and climb up a hill without tipping it more than a few inches...on and on.

Compared to this, the shuttle seemed boring and pedestrian. Smaller and less powerful, it wouldn't visit other worlds. Even its name acknowledged lesser expectations; it would simply "shuttle" back and forth between the earth and some nearby orbit, never venturing more than a few hundred miles from the planet--not a journey so much as a commute.

But my perspective on the shuttle changed. Making the Nova show Hubble's Amazing Rescue, I was lucky enough to spend two years following the astronauts and engineers working on the final repair of the Hubble Space Telescope.

With that experience, I got to know more. I spent time with people who work on and fly the shuttle. I got to see one, Atlantis, up close, close enough to touch it. And I saw it launch, carrying seven people who I had gotten to know and like.

It's seven months since I last blogged about Hubble

Less than five weeks after my last post (from the September press conference announcing the results of the mission), our film was broadcast and my work on the project drew to a close.

For scientists and humans everywhere who want to see what's out there, it has been the beginning of a new age, driven by a reborn Hubble that's many times more powerful than it ever was before. In just a few months of operation, the rejuvenated telescope has set new records in long-distance observations. 

And since distance equals time in astronomy, Hubble seeing farther away into space means we're also seeing closer to the beginning of the universe.  Hubble has now captured images of the earliest and most distant galaxies ever seen, groups of stars that were burning 600 to 800 million years after the Big Bang.

For astronomers who study the history of the universe, this early period is considered the dark ages, a time that we know little about - but Hubble is beginning to change that.  The telescope is revealing some of the earliest galaxies to form after the Big Bang, and scientists are finding them quite different from what they're used to seeing.  These baby galaxies are smaller, and shaped differently; rather than ellipticals and spirals, they appear irregular and disheveled. Their light is also bluer -- consistent with what would be expected from the earliest stars ever born.

Much of these revelations are a result of stunning imagery coming back from the Wide Field Camera 3 - the very camera that almost never got installed because of a stuck bolt on spacewalk #1.  

That fact alone reminds me in a vivid way how all this exciting science about the dawn of the universe would not be happening if it weren't for those seven astronauts who went to Hubble, and especially the four spacewalkers who actually had their hands on the telescope.  All the grand scientific theory that will come from the new Hubble is rooted in the ability of a guy with his hands on a wrench to free a stuck bolt.

Well, it's official: the astronomers are completely ecstatic!  And the science results of the mission are actually just beginning to come in.
 
Ed Weiler starts off the proceedings and echoes thoughts I've had myself recently - he calls the mission "a teachable moment in unparalleled teamwork."
 
He introduces Senator Barbara Mikulski as "the Godmother of Hubble."  Mikulski, in a wheelchair with a cast on her ankle, obviously feels strongly about Hubble; she calls the telescope "one of the greatest forms of public diplomacy that the US has," and reminds us that what Hubble does is open and public and given freely to the world.
 
Barred Spiral Galaxy NGC 6217
Photo Credit: NASA, ESA, and the Hubble SM4 ERO Team
She sounds a note of pride as she comments "We thank all our international partners - but when it comes to space, we are the indispensable nation."  And she concludes by saying that Hubble is "about science, it's about discovery, it's about our American character and the future of our children."
 
I'm hearing that the Augustine panel is very close to releasing their report on the future of American human spaceflight (which is rumored to be pessimistic because of lack of funding) and I wonder how much Mikulski intends her comments to sound a defiant note in the face of such uncertainty.
 
Then we get to the specifics.  The new Wide Field Camera is working better than expected.  The camera almost didn't get installed because the one bolt holding in the old camera got stuck - so the line is "Never have so many scientists owed so much to two guys who fixed a stuck bolt."
 

Morning rush hour traffic in DC is awful, but we're parked and loaded in at NASA HQ by 10 am.  The auditorium is empty so far, but there are a bunch of seats reserved; I see name placards for the astronauts, the new NASA Administrator Charlie Bolden (himself a former astronaut who coincidentally was pilot on the mission that launched Hubble in 1990), and Senator Barbara Mikulski, a longtime passionate champion for the telescope (aka "Hubble Hugger").
 
Suddenly a group of well dressed young men and women appear, and an intense conversation ensues between them and several NASA Public Affairs folks.  They're discussing the choreography of who will introduce Senator Mikulski and Administrator Bolden, where each person will stand, who speaks first, when the mic will be turned on and off, etc.  It's a little glimpse of the kind of stuff I imagine happens all the time in Washington - the handlers working out the details of the dance for the powerful people they represent.
 
I run into Mario Livio, astrophysicist at the Space Telescope Science Institute; the last time we saw each other was in May at Cape Canaveral, watching the launch from the roof of the CBS News building.  He confesses that watching the shuttle roar into the sky carrying his friends on that momentous mission, he briefly teared up that day.  I tell him I had seen the emotion he was feeling, and in fact, though I had far less invested in the event, that I had felt it too.

It's 10:45 AM now, and the place is really filling up.  I recognize faces I saw every day in Houston during the mission: scientists, writers, science journalists, Goddard engineers, NASA Public Affairs folks from the various centers.
 
I overhear Matt Mountain, Director of the Space Telescope Science Institute, joking with a friend (who's obviously a fellow astrophysicist): "I get to take credit for something I did absolutely none of the work on - I love this job!"  He's far too modest; Matt may not have gone into space, but he worked the mission tirelessly in Houston, and I know the long hours he kept there.  Plus, not only does he run the place that runs the Hubble, he's also one of the most effective speakers and "translators" of science for regular folks that I've ever met.
 
The place is now full, and I see Senator Mikulski (in a wheelchair) is now in place; they're minutes away from starting...

Flew to Maryland on Tuesday; departure from Boston was delayed two hours, and then we sat on the runway 30 minutes waiting for a gate at Baltimore.  I've lost count of the number of trips to Goddard and Houston over the past two years, but I do know I've never traveled so intensively in my life.  Arriving last night, I realized that the BWI airport is now so familiar to me that I recognize on sight certain TSA security screeners and car rental agents.  Wow - that's not a good sign...
 
This morning NASA Headquarters will be releasing the first images from the new Hubble.  It's interesting; watching the astronauts and engineers prepare and practice over the past two years, I've gotten so immersed in the process that sometimes I almost forget the ultimate goal.
 
All that time and effort practicing the spacewalks...  all those ingenious tools...  all the support people inspecting each and every one of the shuttle's 24,000 heat tiles, and attending to a million other details.  (Last night I had trouble falling asleep; I pulled out a media reference guide and read the shuttle weather launch rules - two solid pages devoted to weather requirements for launch, including temperature, wind, precipitation, lightning, and ten different rules about types of clouds).
 
And, of course, all the incredible power of the launch itself, shaking the ground, the buildings, my feet and chest from three miles away.  All that power, all these people and work and time and money, all of it for one ultimate purpose: the science to be gained from the images.
 
Trying to put the entire endeavor in perspective, it's kind of inspiring to think that we, as a nation or just as humans, will make this kind of extraordinary effort for no other reason than simply to know.  It's easy to get swept up in the details - they're so extraordinary and the techno stuff is just plain fun, for me at least.  But today I'm struck by the larger purpose: billions of dollars, tens of thousands of people, years (in some cases, lifetimes) of work, all focused on answering one really basic but profound question: what's out there?

 

Publicist Note: Rush DeNooyer is a producer for NOVA's upcoming Hubble's Amazing Rescue premiering Tuesday, October 13th at 8PM ET/PT on PBS (please check local listings). Tomorrow, Rush will be blogging from the NASA press conference where new photos taken by Hubble will be unveiled.  You can read Rush's notes that chronicle his experience filming the Hubble Mission at Follow the Hubble Repair. 


It's a little over three months since the mission ended; I haven't blogged since Memorial Day when I got back home to the small Maine town where I live and started trying to put the whole experience in perspective.
 
For the astronauts and engineers, the mission peaked in late May when the shuttle Atlantis brought everyone home safely, with all repairs complete.  For our NOVA team, the mission is peaking over the next few weeks, as we race to finish editing the film, adding music and animation, and creating the ending to the story.  Naturally, the ending won't be complete without the first images from the new Hubble.
 
So today I fly to Maryland, and Wednesday morning Goddard cinematographer Mike McClare and I will go to NASA Headquarters in Washington for a press conference - the eagerly awaited unveiling of the first images from the rejuvenated Hubble.
 
Actually, early this summer they released a sneak preview when a comet unexpectedly slammed into Jupiter and left a huge visible scar.  But other than that, the scientists at the Space Telescope Science Institute (STScI) in Baltimore have been very secretive, as they've been calibrating all the new and repaired instruments.  No images will be seen until tomorrow.
 
I've pumped my sources at the Institute for information though - and they're telling me that all the repairs seem to have worked.  And they expect people to be blown away by all the things the new Hubble will reveal over the coming months.  I guess the analogy is if you had the same digital camera you bought in 1993, and then replaced it with a brand new one - in the case of one new instrument (Wide Field Camera 3), that's the kind of improvement we may see.
 
On Thursday, we'll film some specialized close-ups of some of the unique tools that Goddard engineers designed for this mission.  And then on Friday, we're filming with Dr. Matt Mountain (Director of STScI) to have him explain for us what the new images reveal, what their significance is, and what future hopes he has for this "brand new" 20-year-old space telescope. 
 
The press conference is midday on Wednesday, and I hope to be able to write directly from there - stay tuned!
 

Here are my notes from Monday

Following Sunday's landing, we catch a late afternoon flight out of Orlando; by the time I finally walk in my door back in Maine, it's 1am.  I've been on the road for 17 days.

Monday morning I attend the Memorial Day parade in my little town, and am overwhelmed with culture shock.  I chat with my neighbor, who makes his living as a logger.  He's an extremely intelligent guy, but he's not had much opportunity to travel in his life.  He's pretty skeptical about the space program, doesn't understand why we send people into space, or what they do once there.  And he's not real supportive of continuing it.

In that respect, he's probably far more typical a citizen than I am.

After the parade, sharing coffee and conversation in the general store of a small rural town, I think about what America has done in space, what we're about to do, and what it all means.

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.

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 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.