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Astronauts to install a window on the world

Jonathan Amos | 19:26 UK time, Friday, 5 February 2010

The weather is looking good here at the Kennedy Space Center for Sunday's pre-dawn launch of the Endeavour shuttle.

Node 3 and the Cupola are prepared for flightWe had torrential rain and tornado warnings on Friday, but the forecasters say there is an 80% chance of acceptable flight conditions come 0439 EST on Sunday.

The weekend's launch is an important moment for Europe and its involvement in the space station project.

The Endeavour orbiter will deliver the final planned connecting unit, known as Node 3 or Tranquility, and a dome shaped element with windows referred to as the Cupola.

Both units were made in Italy by Thales Alenia Space. Thales has now produced about a half of the total pressurised volume on the US side of the platform.

I'm sure most people probably don't realise quite how much of the station's structure has been fabricated in Europe.

Much of it is the result of clever barter agreements signed between the US and European space agencies (Nasa and Esa) in the late 1990s.

Fitting the largest window in spaceWithout a means to deliver its Columbus science laboratory to the ISS, Europe agreed to make Nodes 2 and 3 for the outpost for "free". In return, Nasa waived the cost of the February 2008 shuttle launch that transported Columbus to orbit.

It was a smart deal because the cash that would otherwise simply just have been given to the Americans was instead invested in European industry, advancing its expertise in human spaceflight engineering.

Tranquility is a very sophisticated module and once on station will house its core life-support systems.

Its delivery, though, is being somewhat overshadowed by the Cupola, which contains the biggest window (at 80cm diameter) ever sent into space.

Artist's impression of the CupolaWhen you talk to astronauts, the Cupola is the one module they all say they want to see installed. And yet, this hardware has had to struggle to find itself a slot in the station assembly sequence. Indeed, it was abandoned twice.

The first time was before ISS construction had even begun, when the design of the station was scaled back and it was decided the domed window unit would not be a priority.

The module's manufacture was subsequently picked up by the Europeans under another of those barter deals, but the Cupola then found itself without a ride.

Its launch slot had been dropped as Nasa, reeling from the Columbia accident, re-scoped the station architecture again and reserved the final space shuttle flights for those ISS components deemed absolutely necessary.

From 2004 onwards, the Cupola sat in the corner here at Kennedy's Space Station Processing Facility. The museum beckoned.

But in the background, the astronauts were pushing to have the Cupola re-instated. And then Philippe Deloo, Esa's project manager for the Nodes and Cupola, cracked a joke:

"Offline in a small group of Nasa counterparts, I made the joke that we should fly the Cupola attached to Node 3. At the time, this was for me a joke because I didn't really believe in it. I don't know if that's what triggered the decision but basically a request from Nasa came back in 2006/7 for us to investigate the feasibility of doing it."

Details of window constructionIt's probably the best joke Philippe Deloo will ever tell. The Cupola will travel to orbit on Sunday attached to the front, or end cone, of Tranquility.

It wasn't designed to do that. It was designed to launch on a shuttle pallet. Engineers had to check the new method of carriage was possible. They've had to put in place some contingencies, but the bottom line is that the dome flies.

Once on station, it can be re-positioned to a hatch that has the correct connections to support its functions. This is on a downward facing port. When all the shutters are open, astronauts will be able to look along the full length of the station's belly.

And, of course, the Cupola will also offer a jaw-dropping view of Earth. Simonetta Di Pippo is Esa's director of human spaceflight:

"I had some astronauts who are now retired telling me: 'We would love to fly again just to look outside from the Cupola'. You know, when you spend so much time in orbit, far away from your family, far away from the Earth - it's important that you can look outside. Psychology, it's important. Talking to the astronauts, for them the Cupola is a big step."

The shutters won't be left open all the time. In fact, most of the time they will be closed. This will ensure the glass maintains its clarity and integrity for as long as possible.

These are thick windows, the 80cm-diameter one in particular. Philippe Deloo explains the construction:

There are four panes of glass. In the middle, there are two pressure panes. One is the primary pane; the other is redundant - it is there in case the first one fails so you still have a barrier to maintain the pressure. Both of these panes are 3cm thick.
And then there are two thinner panes just over a centimetre thick. On the outside is the debris pane. It's there to protect the structural glass from micrometeorites, crew kick loads, tools, or whatever might be floating around. And then you have the same thing on the inside to protect the structural glass from the crew.

And if you're wondering: yes, they can be replaced if needed. That would be some glazing job, though.


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  • 1. At 09:47am on 06 Feb 2010, The Realist wrote:

    Well it's nice to see they are giving something to people that risk their lives who go up there. It would be nice for the agencies to send up the former residents of ISS as well to give them a chance to see Cupula forst hand. I am sure they can still contribute to science during a short stay.

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  • 2. At 12:20pm on 06 Feb 2010, Pp wrote:

    "redundent"? English is not my first language but perhaps you meant "redundant" Jonathan Amos?

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  • 3. At 12:33pm on 06 Feb 2010, James Makepeace wrote:

    I have no idea where the graphics came from showing a section through this window for the ISS, but it seems unlike the BBC to allow not one but TWO spelling mistakes in such close proximity (or even at all !)
    Tyy looking up "presure" and "redundent" in the Oxford English Dictionary !!!
    Come on BBC ... you can do better than that !!!!!

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  • 4. At 12:50pm on 06 Feb 2010, Larry Hermann wrote:

    Saturday morning - 52 miles from shuttle launch. Am keeping my fingers crossed that we have cloudless weather [like we have this morning] tomorrow... I stand in the street in front of my house and look SE from here to watch the launch. It's really spectacular... with a 300 ft tongue of flame out the back as the boosters do their job.


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  • 5. At 1:06pm on 06 Feb 2010, Mark wrote:

    You've also got the vacuum/ambient gaps backwards.

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  • 6. At 1:08pm on 06 Feb 2010, Gabriel Oaks wrote:

    Astronauts were perplexed by the knocking on the module hatch.

    Yes, the replacement-windows salesman had decided to call....

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  • 7. At 1:46pm on 06 Feb 2010, BeyondThePale wrote:

    "And if you're wondering: yes, they can be replaced if needed. That would be some glazing job, though."

    If Autoglass do it, do you get it free on fully-comp?

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  • 8. At 4:45pm on 06 Feb 2010, Jonathan Amos wrote:

    Thanks Pp, Mark, James. I've removed the graphic and asked the team to fix it and pop it back in. Cheers, I'm indebted.

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  • 9. At 4:55pm on 06 Feb 2010, curiousman wrote:

    Hi Jonathan
    Could you get the web team who does your BBC search angine to ensure when I type "spaceman" in the BBC search box it comes up with your blog site. It doesn't mention it at present. Even typing in "Jonathan Amos" doesn't seem to bring you to the fore!

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  • 10. At 6:07pm on 06 Feb 2010, Macin Tosh wrote:

    how does its mass change from "launch mass 1805kg" to "on orbit mass 1880kg"?

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  • 11. At 8:44pm on 06 Feb 2010, Jonathan Amos wrote:

    @curiousman: I'll have a word with our search team. You've probably noticed they've made a number of changes to the engine recently. You will start to see more and more themed result pages appearing when you make a search. @MicroCosm: When the modules are launched, they do not always fly with all the equipment they will eventually host. Node 3, for example, will have a lot gear brought into it that is already on station, such as the Environmental Control and Life Support Systems and the famous Colbert treadmill.

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  • 12. At 03:43am on 07 Feb 2010, John wrote:

    Of all the modules up there, and all the science and construction that has gone on with the ISS, the Cupola is the most important feature!. The Cupola is the gold medal prize winning view of Earth for the astronauts that spent there whole lives wanting to travel to space.

    Its going to be beautiful, i think Arthur C. Clarke would have been proud to see this module installed on the ISS. If i was up there, i would want to eat, sleep and work inside that Cupola. Its the stuff of dreams, this is science fiction becoming reality!

    Wish i could be there to look out that window. The view would almost be worth the 20 million dollars.

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  • 13. At 04:33am on 07 Feb 2010, David G wrote:

    I suppose it will be nice for the astronauts to be able to look out of their newly installed window at the $100 billion white elephant in which they are riding. (For a breakdown of costs see: ).

    While they are admiring the view of the earth they might wonder how any science done on the ISS could possibly justify the cost - but it will only take them a fraction of second to conclude that this is impossible.

    They might turn to thinking about all the science that could have been done on earth with $100,000,000,000 but they probably won't because this would be too depressing…

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  • 14. At 10:19am on 07 Feb 2010, beechy wrote:

    Hm I see what you're saying David, potentially a lot more beneficial science could have been carried out with that money. But I don't personally feel it has been a waste. Also this $100 billion should really be put in context with the recent $3 trillion bank bail-out and stimulus packages spent in the US alone (, and also with the $1 trillion dollars spent on the Iraq/Afghanistan wars (, just think how much science could have been done with that money. That's what I find depessing.

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  • 15. At 10:04am on 08 Feb 2010, David G wrote:

    If I spend millions to design, develop and produce a sledgehammer in order to crack a nut it would not be strictly correct to say that I had wasted the money - after all I would have been able to eat the nut.

    The fact remains that if I had put the money into developing a range of machines that could crack all kinds of nuts at the rate of thousands of nuts per hour the money might have been better spent…

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