All posts by johnruhl

Antarctica 2014 – Spider in McMurdo

This is a belated start to posting from our 2014 campaign…

I left the US on 11/1, the day after Halloween.  My itinerary took me to Dallas, then Los Angeles, then Sydney (Australia), and finally to Christchurch, New Zealand.  Here’s my giant (double decker!) plane for the 15 hour flight from LA to Sydney…



… and here we are dropping into the well-manicured city of Christchurch, NZ, about 33 hours after leaving Cleveland…  Note the proliferation of hedges!


The next day, we got our “Extreme Cold Weather Gear” at the US Antarctic Program’s “Clothing Distribution Center”.



Here are a few of us trying on all the gear, which comes in two orange bags per person…



Here’s my kit, before I changed out the boots and pants for a slightly different type.  The “Big Red” parka, a “Little Red” (uninsulated) wind jacket (not shown), some insulated pants, and super-warm boots… plus a bunch of warm long underwear (tops and bottoms), a fleece jacket, warm socks, and various gloves, hats and a neck warmer.  Enough to stay warm, even down there (we hope!).



Next up… our flight to Antarctica, which was one day later… but that’s another post!

6 weeks later…

Severe lack of posting… but much progress.   I’ve been in and out of Palestine several times now, but the team has persevered and gotten SPIDER together.  We’re doing “full up” tests now, and getting all the on-board software that runs the thing into shape.

The payload sure looks impressive… here it is, looking out the highbay door at night while mapping telescope response on a “hot source” in the parking lot.  We have five of the six telescopes in place – the dark circles are baffles that keep stray light from getting into the telescopes.  The whole payload is, in this picture, hanging from a crane, scanning back and forth driven by its onboard systems.

Here’s the source – it’s just a small hot “oven” with a circular hole in it, broadcasting thermal radiation (its “glow”) toward Spider.  You can barely see the source in this picture, but you can see how it’s set up high on a lift bucket.  The big black sheet is for some “fake stars” used during the daytime scanning, so the star camera has something to look at.  At night, like in this photo, the gondola pointing is controlled using the real stars in the background!
When we’re doing these tests, the team is inside the highbay working to control the instrument;  here’s Jamil, a UToronto grad student, controlling the gondola motion from his laptop.

The balloon base is a beautiful place at night;  here’s the big water tower, in a very overexposed image, with its red light (so airplanes from the nearby airport won’t hit it) on top.

And, very late at night, we undoubtably get a little slap happy at times.  Here’s a “creative” shot of Sasha and Sean, getting ready to leave for the night.   I had been playing with long exposures outside to get the water tower picture, and took a long shot while rotating the camera to get this.

more arts and crafts, closing time

I had to return to Cleveland on Thursday night, but here are some pictures from before I left.  Lots more “arts and crafts” to get things ready…

Natalie (U Toronto grad student) applying aluminized mylar tape to the inside of an electrical box, which helps cool the components when the instrument is up wehre there’s no air…

and Lorenzo (Caltech postdoc), buttoning up a receiver

and Bill (Princeton prof) using his favorite tool, the power drill.
You would think that we were always serious, toiling away at our science, but here you see the usual mood, which is rather upbeat – in this case Anne and Jon doing some wiring
Sean doing some dremeling,
and Ziggy (Pton postdoc) doing some painting with black goo on our 2K baffles.
Finally (for the arts and crafts pictures), here’s Barth, examining the big carbon-fiber support the UT group built for the sun shields… this is going to look very interesting, when on the gondola!
The afternoon before I left, I took a walk out to the launch pad, where they (used to) launch balloons, and where you can get a great view of the highbay we work in, with the water tower behind it.
Today, from what I hear, the top and bottom domes went into place, so soon the cryostat will be on the pump.  I’ll be headed down in earlyish July to help with the optical testing, once the thing gets cold… keeping fingers crosse for all that!

Arts and Crafts

Some people think that scientists sit at computers all day.  Or wear white lab coats, perhaps working with fancy instruments with streamlined panels and lots of buttons and lights.  One of the great things about building a new instrument like Spider is that we often get to do hands-on arts and crafts.

That’s right, to be a experimental cosmologist you need to tape, glue, and use scissors.

Here’s Ed, a graduate student from Princeton, doing some taping of a special filter that’s part of our telescope optics…

and Anne, another Pton grad student, doing some aluminum taping,
and Johanna, one of my students at Case Western, after assembling a filter stack (the mirror-like thing),
and Becky, a Caltech graduate student, playing with a filter assembly.  (Okay, she’s actually working, not playing… but it looks like fun, right?)
Finally here’s yours truly, taking off some electrical connectors at the bottom of the cryostat (which involved undoing tape and string), as part of getting ready to put telescopes into the cryostat (where they live during flight) for fit checks.
All the arts-and-crafts work got our telescopes a little closer to being ready to put into the cryostat… a couple more days and we hope to have them in place.  We did discover one small “feature”, an alignment issue of the telescopes with the halfwave plates at the top of the cryostat;  we’ll have to adjust the alignment of each telescope to its particular halfwave plate in a custom fashion, since we found the first one was a little out of alignment if we just put it in its default position.  This isn’t a big deal, but gives us a little more “arts and crafts” to do over the next couple days!
So, if you want to do my kind of science, learn to cut, tape and glue well… and because we work in groups and rely on eachother to figure things out and get things done… practice playing well with others.  🙂

Spider: the journey begins in Texas

For the past… maybe 7, 8? years or so, we’ve been working to build a balloon-borne experiment to measure the polarization signature of Inflation (if that signature is there) in the Cosmic Microwave Background radiation – the remant glow from the big bang.   We call it “Spider” because that made some sense in the early days given what it was supposed to look like and do… the design has since changed but the name stuck.

Finally, the instrument is coming together. We’ve just begun our “integration campaign” in Palestine, Texas, at NASA’s Columbia Scientific Balloon Facility. We’ll spend the next couple of months getting the instrument together and checked out with NASA’s flight equipment, after which we’ll box it up and send it off to Antarctica for the flight in December. (More on that later).

 The first people on our team arrived a week ago, and I just got here today – I had to finish up a little hectic last-minute work on some hardware we need here before I could come down. It’s getting late on the first night here, but I thought I’d post a couple pictures. Here’s the highbay we’re working in:

 The big doors are so tall because the payloads we work on have to be picked up by a crane to be pulled out of the building once they’re completely assembled. Tomorrow I’ll post pictures of the highbay from the inside. Here’s a sunset shot looking through the trees to the balloon launch pad they have here – quite a beautiful site in West Texas… sunset is always welcome when the day was in the 90’s.

 Finally, for the aficionados, here’s a picture of five of our receivers (aka telescopes) getting put together… still lots to do, but things are coming together fast!

 Finally, here’s a terribly-focused picture of some of the crew in the kitchen/eating area in the highbay enjoying home-cooked pizza, thanks to Jon Gudmundsson, one of the Princeton grad students, who slaved over a hot oven for our benefit. Thanks Jon!  (That’s him in the back, in the brown shirt)


Polar vehicles

There are definitely some funny-looking, unique, vehicles down here… In addition to the snowmobiles pulling sleds that we ride behind on

and interesting planes,

here’s a really good one – a modified van, with tracks instead of wheels!

The tracks help it go over the soft snow, especially early in the season when the “roads” have not been compacted enough by travel.

Finally, here’s both a “lift bucket” (the orange thing) that raises up workers that are doing something up high, in this case taking down some “side shields” from our telescope to make room for a new “guard ring” around the primary mirror… and a crane (the black thing) that is lifting the heavy parts to bring them down to the ground once they’re detached.

The cold weather is hard on all these vehicles – they break down a lot, but there’s a full time shop here that fixes them and keeps them going. It takes a lot of work down here just to supply us with all the things we need to get our job done. All that is taken care of by Raytheon Polar Services, the “contractor” hired by the National Science Foundation (who gave us the grant to do our work, too) to take care of operations and logistics for the US Antarctic Program. So, we don’t have to worry about heating our buildings, getting electricity, finding or cooking food – it’s all taken care of by NSF and Raytheon. (A big thanks to them!)

The Pole(s)

My sister Anna’s husband Shawn asked me how close the station is to the real, geographic South Pole. Well, here’s a picture of me at the Pole marker… with the blue station building in the background to the left. Very close!

The galley windows look right out over the Pole marker, so the Pole is in view at every meal. 🙂

Interestingly, the Pole marker is re-surveyed (using GPS satellites these days) every year; the 2-mile thick ice sheet that our station rests on is slowly flowing toward the ocean, which means that the station moves with respect to the rotation axis of the earth, the Pole. That movement is about 30 feet/year, so every year when the pole marker is re-surveyed it is moved about 30 feet… to the left in the photo above. I first came here in 1988, 23 years ago, so the Pole marker has been moved about 700 feet in that time!

I’m not sure why, but the NSF also sets up a “ceremonial pole” surrounded by the flags of all the treaty nations. It’s marked by a shiny ball on a barber pole. Here’s a closeup of the ball, with yours truly in reflection.

Many years ago the ceremonial pole was much closer to the station than the actual geographic pole… so it was easier for visitors to get there and get nice pictures… but now the geographic pole is actually closer… 30 years from now the geographic pole will again be further away, unless they move the station!

South Pole Traverse arrives!

As I mentioned before, almost everything we use here at the Pole is delivered by C-130 aircraft. Historically that includes all the fuel that is used to run vehicles here, and to heat and generate electricity for all our buildings. That’s a lot of fuel.

A few years ago they started a “traverse” over land from McMurdo to the Pole, consisting of big tractors pulling “fuel bladders”, or heavy-duty rubber bags of fuel. It’s much cheaper to get the fuel here by that route: in an airplane, for every one gallon of fuel delivered to Pole you burn another 2.5 gallons or so getting it here. By land, it’s 0.5 gallons burned to deliver 1 gallon. (I’m quoting these from poor memory, but will check and correct if they’re off – at any rate, it’s a huge efficiency difference).

They arrived, after 31 days “on the road”, here at Pole early today. By the time I got out to see what was going on they’d unhooked their fuel sleds and parked all their vehicles, but we did talk to a few of the 10 guys (one per tractor) that made the trip. Here are some of the tractors they drove.

They have to be ready for anything along the way – if a tractor or sled breaks, they have to fix it. So, they tow two trailers filled with mechanical supplies and tools, and several of the drivers are heavy-equipment mechanics. Here’s their mechanical supplies/tools trailers:

They sleep in trailers too – here’s the trailer that 8 of them sleep in, which also has a little communications center, a small kitchen and table in it.

Finally, here’s me standing in front of one of the sleds with “fuel bladders” on it. Seeing all this reminds me how odd and unique of a place I’m in – where else gets its fuel delivered like this? 31 days of driving tractors across an ice shelf, up glaciers and across the polar plateau to deliver this to us? This is indeed a place of extremes.

Closed up, telescopin’

We finally, finally, after many hitches, got the optics cryostat closed up. Here is a picture of us flipping the big lid before putting it on:

You may notice two things in that picture – first, I’ve got the funny face of someone taking their own picture with outstretched arm, and second, I haven’t shaved in a week and a half. Beard is growing. 🙂

Here’s what it looked like inside just before closing:

The shiny wrapping in that picture is a heat blanket that helps the insides stay cold. The copper pipe is a “lightpipe” that we use to send in an optical signal from the outside, through a small hole in the secondary mirror inside this cryostat.

We lowered the lid gently onto the other half and made the vacuum seal, tightened all the bolts and this is what it looked like in the end:

Meanwhile, the night shift crew has been playing with cranes around the telescope, taking off some parts that we’re going to re-do this year. Here’s a picture of the crane swinging into place to take off some shielding. The yellow arm is a “bucket”, which lifts a person up in the air to do work in high places.

Lots of activity, lots of progress! Still cold, though: -24.9F, -47F windchill as I write this…

What we do at work here

We’ve been here at Pole almost two weeks, and I’ve not yet showed you our telescope, or told you what it is that we’re doing here.

The South Pole Telescope (or SPT), shown below, has been observing
the cosmic microwave background for the past 5 years.

The primary mirror is 10 meters, or about 30 feet, in diameter. Light coming from the sky bounces off that mirror and is focused down through a window into the receiver cabin. That’s where the rest of our optics and our camera sit. The receiver cabin is heated, so we can work on all that equipment… but it’s hard to work on it when it’s pointed up in the air. So, we built the control room with a sliding roof and the receiver cabin with doors on its bottom, and we can point the telescope to dock the receiver cabin floor with the control room roof, open all the doors and easily work on things without going outside. Here’s a picture of the telescope docked. The green “boot” seals the cabin to the control room.

When we first arrived here, we stopped observing and pretty much immediately docked the telescope so we could bring the secondary optics and camera down from the cabin into the control room to work on them. We’re installing a new camera this year, and our job is to change some of the optics for that camera. We also put in some new anchors up on top of the cabin to accommodate a new baffle that will be installed later in the season. Here we are working up on top of the telescope, when it was -40F outside, windchill of about -70F.

The circular thing in that picture is the vacuum window of the optics cryostat (which keeps the secondary optics very cold, 10 degrees Kelvin, more on that below), which was still mounted up in the cabin at the time.

Moving inside, here’s a picture taken inside the control room, looking straight up (about 20 feet) at the optics cryostat and the old camera, just as we were about to lower it into the control room.

It took a couple hours, but we got it down from the cabin, into the control room below. Here it is sitting on its cart, ready for us to start working on it.

We then took the camera off the optics cryostat, and opened up the optics cryostat to reveal its guts. Here’s Ken with the cryostat just as we were about to lift out the guts

The big silvery thing is an assembly that includes the 1 meter diameter secondary mirror and some heat shields and black baffles that keep us from getting bad images due to stray light bouncing around inside the cryostat. The heat shields help us cool the secondary mirror and black baffles to 10 degrees Kelvin, just a little above absolute zero.

We took the assembly apart – here’s me with the secondary mirror, and the baffles and heat shields behind me.

Notice that even though I’m inside I’m wearing a warm fleece jacket and insulated overalls – the control room gets pretty cold when it’s windy outside.

We put a new set of baffles and heat shields, which we brought down with us, on the secondary mirror and reassembled everything. Here is the new assembly – you can see the old one in the background.

The alignment of the heat shields with the cryostat, in particular the opening where light goes into the camera, is very critical and tough to make work correctly. Here is a picture of the setup as we are just about to test-fit the new ones into the optics cryosat.

We had to put in and take out the whole assembly (to readjust it) 3 times before we were happy with the alignment. We put it in for the final time the day before yesterday, and right now we’re doing the final “buttoning up” of everything, checking all the wiring, installing optical filters, etc, before we close up the optics cryostat hopefully for the final time.

And, to reward you for reading this far, here is a poor picture, taken with my small “point and click” canon camera through two layers of aluminized mylar (like the shiny silvery stuff helium balloons are made out of) of the solar eclipse (moon passing in front of the sun) we had here two days ago. In this picture the sky appears black – that’s just because I had to use the aluminized mylar to reduce the glare from the sun enough to get a good exposure. In reality, the sky was still very blue, and in fact the brightness level only dipped a little, it seemed… enough that you could comfortably look around without sunglasses, but still a very bright day.