Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
×
Space Science Technology

Exceptional Seeing At Dome C in Antarctica 252

Michael Ashley writes "A paper published in Nature today reports on the exceptional astronomical seeing conditions at Dome C (Coral link) in Antarctica. Obtaining the data posed some significant technological challenges, given that Dome C is uninhabited over winter. The experiment was controlled by a PC/104 computer system that had to survive temperatures down to -85C, and supervise the generation of its own electricity using a jet-fuel powered stirling engine. The computer, running Linux, communicated with the outside world using an Iridium phone. The results are also covered in New Scientist, and the Sydney Morning Herald. Disclaimer: I'm a co-author."
This discussion has been archived. No new comments can be posted.

Exceptional Seeing At Dome C in Antarctica

Comments Filter:
  • by nlawalker ( 804108 ) on Wednesday September 15, 2004 @04:05PM (#10259507)
    Looks like making the ozone hole actually accomplished something.
  • by Anonymous Coward
    polluters, the other scientists.
  • Vow (Score:4, Funny)

    by savagedome ( 742194 ) on Wednesday September 15, 2004 @04:07PM (#10259526)
    Dome C is uninhabited over winter. The experiment was controlled by a PC/104 computer system that had to survive temperatures down to -85C

    Now, that's a savage dome!
  • by grape jelly ( 193168 ) on Wednesday September 15, 2004 @04:07PM (#10259531)
    The experiment was controlled by a PC/104 computer system that had to survive temperatures down to -85C...

    Wait a sec! =-P Computing equipment *loves* cold, as long as you don't have to worry about condensation. =-P In other words, it's not hard to design a system that can survive -85C. Just do a google search for Liquid nitrogen cooling [google.com]. Yay for overclocking fiends who make it so you don't even need to mention computing hardware. ;-)

    btw, there's a tom's hardware link on the results page. Check it out. There's a pic of a CPU mount covered in frost. That *can't* be good! =-P
    • by Homology ( 639438 ) on Wednesday September 15, 2004 @04:13PM (#10259592)
      Large fluctations in temperature can be quite bad for hardware : it will contract and expand, and thus inducing stresses on the computer. And relability is a big factor : You can't just fly down there to replace broken parts.
    • by Waffle Iron ( 339739 ) on Wednesday September 15, 2004 @04:20PM (#10259654)
      When you do a circuit design, you take into account both maximum and minimum delay paths. These are usually spec'd over a recommended operating temperature range, which most likely doesn't get quite that cold.

      While colder can often mean faster, sometimes a signal requires some minimum delay to work correctly. This is especially true of the minimum hold times required on inputs after a clock transition. So it's possible that some signal might go out of spec if you drop the temperature too far. It only takes a single bad signal to hose the whole system.

      Unlike just dropping the temperature of the CPU chip which will have relatively uniform characteristics, getting the whole system cold might cause a wider range of timing variations. Moreover, even dropping the external heat sink of a CPU to extreme cold doesn't mean the chip itself is in the cryogenic range. They usually run at temps well above the bulk of the heatsink.

    • I'm guessing the CPU doesn't mind so much as the hard drives. Moving parts may not like being that cold...
      • I would just put the parts in an insulated box (not too insulated, but enough). As long as you never shut the thing off, you wouldn't have to worry much about the cold. Do it right, and you could probably keep the temperature of the whole system from fluctuating much at all.

        My guess is that due to power restraints, the computer spends most of it's time powered off, or atleast in an extremely low power state.
    • Cold is fine for the CPU, but what about the power supply, motherboard, etc?
    • by moonbender ( 547943 ) <moonbenderNO@SPAMgmail.com> on Wednesday September 15, 2004 @04:31PM (#10259767)
      Read the part on the events of May 17th 2004 [unsw.edu.au]. This has got to be the coolest troubleshooting situation I've ever heard of. An extract (do read the linked paragraphs for the full story!):
      The PC/104 computer was also on the RS-485 bus, and we reasoned that by rewriting the Linux device driver (which we had written in the first place, so we knew what we were doing) we could make the computer impersonate the control panel, and convince the engine that it should keep running. Fortunately, we had a snapshot of the communication traffic between the engine and the control panel from earlier testing in the lab with the manufacturer's MSDOS-based software. But with no hardware available to test our code, we had to modify the driver, send patches over the 2400 baud Iridium link, and rmmod/insmod the driver to try to restart the engine.
      And to think I get nervous flashing a computers CMOS...
    • by mpoulton ( 689851 ) on Wednesday September 15, 2004 @04:37PM (#10259810)
      Computing equipment *loves* cold, as long as you don't have to worry about condensation.

      Ah, not so! *processor cores* love cold, not electronics in general. Specifically, electrolytic capacitors freeze and fail below their rated temperature, and it's really tough to find any that are rated to temps that low. Also, because of resistance, capacitance, and crystal frequency value changes at low temps, oscillators and filters tend not to behave. This doesn't even consider the issue of thermal expansion coefficient differences causing BGA chips to pop off the circuit boards! Making anything electronic operate in that environment is highly non-trivial.
    • Some electronics operates below its specified minimum operating temperature, and some doesn't. For example, we had some solid-state disks that were rated to -40C, but that failed at -20C. Mostly we have found that PC/104 computers, memory, etc work fine at -60C. M-Systems solid-state disks have been very reliable.

      You want to avoid spinning up a hard disk at -85C though! The altitude (4000m equivalent) also tends to be rough on hard disks (both due to the cooling problems and the smaller head-gap), which is

    • I doubt the board surface temperature actually made it down to -85C. The powered circuitry itself acts as a kind of heater, so as long as it's in a box and powered on all the time it probably kept itself much warmer than this. "Extended Temperature" support in PC/104 boards usually means -40C to +85C.
    • Actually, semi-conductors are only semi-conductors at near room temperatures. If it gets too hot or too cold, your semi-conducting material becomes an insulator.

      strike
  • by kbahey ( 102895 ) on Wednesday September 15, 2004 @04:10PM (#10259557) Homepage

    Look at this photo [unsw.edu.au]. It is the author's Kyocera mobile phone with a web page showing the temperatures, memory usage and free disk space. Says battery temperature is -34.5 (is that C or F?)

  • Seeing Conditions (Score:5, Informative)

    by ottergoose ( 770022 ) on Wednesday September 15, 2004 @04:10PM (#10259558) Homepage
    What is "seeing"?

    "Seeing" is a term that astronomers use to quantify the turbulence in the atmosphere and how it affects observations from the ground. The stars appear to twinkle because of the effect of this turbulence. In conditions of bad seeing, the stars appear to twinkle vigorously, and the images that you take with your telescope are blurry. In conditions of good seeing, the stars appear more stable, and you can take very sharp images.


    You'd think they'd have a cooler word for that...
    • by lucabrasi999 ( 585141 ) on Wednesday September 15, 2004 @04:28PM (#10259749) Journal
      You'd think they'd have a cooler word for that...

      I apologize in advance for recycling an old joke, but here are some ideas for 'cooler words' (and phrases):

      Untwinkly.

      Non-Twinklifying.

      Steady-State Stars.

      De Tinky Winkied Star.

      Sluggish Stars (antonym of 'vigorous').

      Lethargtic star viewing.


    • You'd think they'd have a cooler word for that...

      As someone with myopia, I'd suggest laymen's terms like "20/20" or "20/10" or whatever (what would it be? "20/8") to describe the improved perspicacity available in low turbulence air. [BTW, I'm looking into Lasik and wondering just how good my vision could get...]

      Or, you could perhaps express it in terms of

      At what elevation above sea level would I need to be at the equator or at New York's latitude to gain equivalently good views of the stars? Higher th

  • by GillBates0 ( 664202 ) on Wednesday September 15, 2004 @04:10PM (#10259559) Homepage Journal
    The experiment was controlled by a PC/104 computer system that had to survive temperatures down to -85C...The computer, running Linux, communicated with the outside world using an Iridium phone.

    I would have to say Linux was the ideal choice in this case. Penguins are polar creatures. you know. I wonder how the Microsoft Rainbow-bee-man would've fared under such conditions.

  • by PhraudulentOne ( 217867 ) on Wednesday September 15, 2004 @04:10PM (#10259564) Homepage Journal
    Hell, all that they had to do was stick a new Geforce and an Athlon in there and she'd be warm as toast ;)
  • ... does the PC/104 run Linux? No really, I'm curious ... never heard of it before.

    (Don't bother to mod this post up, I've got all the karma I could possibly spend.)
    • by DiS[EnDeR] ( 195812 ) on Wednesday September 15, 2004 @04:18PM (#10259638)
      A PC/104 is just a form factor. And provides standards for things such as environmental operating parameters.

      CPU boards usually have an intel clone processor MACH86 or VIA Athena.

      So they can run any OS your desktop can.

      • http://www.diamondsystems.com/
        Heres our PC/104 supplier. We also use a GPIB card from National instruments connected to an Agilent Data logger. Add a Modem Card, Video Card, and two DMM32 Data Aquisition cards. Plus the DMM16 thats already on-board.

        The new Athena Processors have video on-board, and faster CPU's.

        I believe Intel sued over teh Mach86 processor and they had to switch.
        • by Voivod ( 27332 ) <cryptic.gmail@com> on Wednesday September 15, 2004 @04:42PM (#10259860)
          The CPU is called the VIA C3 and the chipset is the VIA Eden. The "Athena" in your post refers to a Diamond Systems product name for the board which uses this CPU, not the name VIA calls their own CPU.

          The "Mach86" you're thinking of is the ZFMicro ZFx86 chip. They are battling National Semiconductor, who produced these CPUs under contract for ZFMicro until ZFMicro was no longer able to pay their bills. Intel is not involved at all.

          The other big PC/104 CPU vendors are Transmeta, STMicro (STPC), and AMD (Geode). Recently the Pentium 4-M have been popular for boards which don't need to support extended temperature.

          PC/104 rocks for applications like this. Disclaimer: I work for a PC/104 company. ;-)
    • PC/104 is a form factor and external bus specification, not a CPU type. It could have had any of many embeddable cpus on it.
    • From the article in case it get's slashdotted:

      To operate our experiments over winter, when there was no one at Dome C, we had several problems to address:

      1. For hardware reliability, we wanted to remove all moving parts in the computers, i.e., no disk drives, and no fans. So we used a small PC/104 form-factor computer system with solid-state disk drives.
      2. We had to generate our own electricity. We took two approaches to this:
      1. One experiment, ICECAM, relied entirely on a 5 kg pack of
    • The PC/104 is a standard for the cards that slot into the most common Embedded systems. Oftentimes PC/104 MB's will include a Compactflash or PCMCIA adapter, or expect you to convert IDE to do the same via an adapter.

      In short they are X86 micro motherboards. So yes, they will run linux.
    • Sure why not? It's an x86 so there is no reason you can't boot up a main distro. If you wanted you can run linux on many DVD players too (those that use a DSP)
      -nB
      • by tdrury ( 49462 ) on Wednesday September 15, 2004 @06:11PM (#10260681) Homepage
        as others have said, PC/104 is a board form-factor, but it's more than just a size (roughly 4" square). It also dicates the bus. PC/104 uses .1"x2 stackable headers for the ISA 8-bit and another, smaller, .1"x2 header for the ISA 16-bit bus. The two headers are stuck right next to each other. So you can have non-x86 processors on PC/104 but they must be able to read/control the ISA bus. So chips like the StrongArm must include a little glue logic as a bridge.

        Additionally, there is PC/104+ which includes the 32-bit PCI bus in a 4x2mm stackable connector on the opposite side as the ISA headers.

        There are more features to PC/104 but the size and bus signals are the most important.
  • Corrected Link (Score:4, Informative)

    by Anonymous Coward on Wednesday September 15, 2004 @04:11PM (#10259578)
    The link that the submitter provided to himself doesn't work. The correct link is: Michael Ashley [unsw.edu.au]
  • God I hate those jerks in Dome C!
  • Iridium? Didn't they go out of business a few years ago?

    Or have they switched to niche markets like in this case?

    • Their assets were bought, very shortly before their satellites were supposed to have been deorbited. I don't recall who bought them.
    • by Phat_Tony ( 661117 ) on Wednesday September 15, 2004 @04:37PM (#10259808)
      Iridium was the dumbest investment opportunity since a 3,000 Guilder Tulip bulb in 1624. The constellation cost $5 billion to construct. It was immediately obvious from the very outset to anyone who spent a little while playing around with the math that there would never be any way to make money from this. You could estimate any reasonable supply/demand curve and come up with a loss- from 1 phone at $5 billion apiece to 5 billion phones (about 1 per person on earth who can ho,d a phone) at $2,001 apiece (the phones cost about $2,000 to produce), there was no number in between where they could conceivably ever make money. In fact, there was no way they could do anything but lose billions.

      So they went bankrupt, and no one would buy the system. It was a textbook case of a colossal business failure, and no one would touch it with a 10-ft pole. The judge hated to rule that a $5 billion infrastructure system burn up in the atmosphere, and luckily, at the last minute, Dan Colussy stepped in with a $25 million bid- less than half a cent on the dollar of initial construction costs, and swept it up.

      Then what? The new Iridium Satellite LLC started cleanning up, which it's still doing. Very profitable. It turns out that, while it's impossible to recoup a $5 billion investment on a satellite phone system is impossible, recouping an investment 1/200 that size isn't so bad.

      • This happens a lot. (Score:4, Interesting)

        by juuri ( 7678 ) on Wednesday September 15, 2004 @06:23PM (#10260766) Homepage
        This actually happens quite a lot and is one of the reasons large companies farm off risky things to spinoffs. Typically they wait for the spinoff to flounder AFTER it has sucked in huge amount of external capital and then at the last moment buy everything back for pennies on the dollar.

        A good portion of certain companies DSL setups was done this way.
  • ... oh yes:

    Cool!
  • PC/104 Computers... (Score:5, Interesting)

    by DiS[EnDeR] ( 195812 ) on Wednesday September 15, 2004 @04:15PM (#10259618)
    I work with Diamond Systems PC/104 computers everyday. These systems are robust and the specifications for operating environments are crucial to applications such as these. Their ability to operate in extreme conditions, temperature, vibration, make them fit for such roles.

    We've used PC/104 computers (running QNX 4.25) for everythign from Remote power stations, Fuel cells, even UAV's.

  • This is offtopic, but how's that Coral link thingy work? As it open participation?
  • outta beew (Score:4, Funny)

    by Himring ( 646324 ) on Wednesday September 15, 2004 @04:18PM (#10259636) Homepage Journal
    Base camp: So how's it going there?
    Dome C: Weh, Biwwy daywed me to stiwck my tung to the waw. Oh, and we'we outta beew....
  • Mostly off topic (Score:3, Interesting)

    by bryan1945 ( 301828 ) on Wednesday September 15, 2004 @04:18PM (#10259642) Journal
    But I've applied for a job down there (no reply so out for this year); anyone work down there and have any advice for getting a foot in the door?

    Thanks
  • by notestein ( 445412 ) on Wednesday September 15, 2004 @04:22PM (#10259683) Homepage Journal
    One experiment, ICECAM, relied entirely on a 5 kg pack of lithium thionyl chloride batteries. The batteries had to provide power for a year, so minimized the power consumption of the computer. The experiment only needed to take data every two hours, so we built a CMOS oscillator to power-up the computer for 30 seconds every two hours. We used MS-DOS 6.22 for the PC/104 computer since it boots quickly and was able to average 10 frames from the CCD camera and store them to CompactFlash disk.
  • Thermal Control (Score:4, Interesting)

    by Detritus ( 11846 ) on Wednesday September 15, 2004 @04:27PM (#10259726) Homepage
    One technique that I've seen used is to put the PCB for the computer inside a box lined with foam insulation. This also works with hard drives. The electronics produce enough heat to keep the interior of the box at a reasonable temperature.

    The hard part would be coming up with a thermal control system that worked at both extremes, a hot summer day and the dead of winter.

  • by WormholeFiend ( 674934 ) on Wednesday September 15, 2004 @04:28PM (#10259737)
    so, how far is the secret nazi base [about.com] from Dome C?
  • by arose ( 644256 ) on Wednesday September 15, 2004 @04:28PM (#10259743)
    They seem to maintain a good sense of humor despite the cold. What do the authors look like? [nyud.net]
  • by ewanrg ( 446949 ) <ewan.grantham@gmail.STRAWcom minus berry> on Wednesday September 15, 2004 @04:29PM (#10259755) Homepage
    Not to belittle a heck of an achievement, but I was glad to see the author explain how even under such extreme conditions and with much improved equipment than was used they would be able to do as well as the Hubble only 10% of the time. Which (IMNSHO) again points out the need to keep the Hubble up there.

    However, I think Site C shows promise for imaging sites that are not in the right plane for Hubble to get a look at, or where the long winter night would allow for extended exposures...

    Obligatory plug - please check out my online novel [blogspot.com]

    • There is no part of the sky that the HST can't look at, though obviously at any given time its choices are more limited (e.g. it can't point within 50 degrees of the Sun, but the Sun moves wrt the stars...) The key point about this work is that it would be much, much, much cheaper than HST. Moreover, it's looking at the moment as though the JWST, HST's successor, as well as being very expensive to the US taxpayer, will be restricted to the infrared. A ground-based optical telescope with high resolution cou
    • by Mr_Dyqik ( 156524 ) on Wednesday September 15, 2004 @05:51PM (#10260491)
      We're building a sub-mm polarimeter (Clover)to go to Dome-C (Dome-C is the best site in the world for sub-mm, being high, dry, cold and calm) starting now.

      The total budget is 4.3M GBP, including new detector development, and the telescope will be collecting data from Austral winter 2007 onwards. This telescope will have better results on CMB B-mode polarisation than the Planck satelite mission, before Planck reports results, for about a tenth to hundredth of the cost. The Planck project has a 15 year head start. Admittedly Planck isn't designed to only make the measurements we are trying to make.

      When something goes wrong, we'll be able to send someone out to fix it, and if someone invents better detectors, we can send some out to be installed.

      Hubble is limited to the resolution of its 2m mirror, while optical telescopes on the ground are now reaching 10m (Keck), with sub-mm telescopes reaching 50-100m (LMT and GBT).

      Hershcel/First will be the sub-mm equivalent to Hubble, and is limited to a single 3m mirror, while ground based sub-mm telescopes are using 64 15m mirrors spread across 60 km of the Atacama desert, simulating the resolution of a 60 km mirror.
  • by raehl ( 609729 ) * <raehl311@@@yahoo...com> on Wednesday September 15, 2004 @04:40PM (#10259841) Homepage
    I'm apalled that we are polluting Antartica with this radioactive material. What if the phone melts down? This could have devastating consequences for all of Antartica's residents.
  • Antarctica at night? (Score:3, Interesting)

    by Geiger581 ( 471105 ) on Wednesday September 15, 2004 @04:44PM (#10259877)
    Has to be the most hellish place on the surface of the earth. Dante's Inferno does in fact have the very heart of hell full of darkness and ice, in fact. A more miserable condition than any volcanic brimstone, I'd say.
    • Let's try an experiment. You and I each get
      $1,000 to buy clothing for our chosen destinations. You hike through the molten lava fields into the active volcano and back out (ha!), and I'll hike the equivalent distance across any part of the south polar shelf. Who's going to be alive when the helicopter comes back?
  • Sterling engine? (Score:3, Informative)

    by alwaystheretrading ( 750171 ) on Wednesday September 15, 2004 @04:57PM (#10259985)
    ...and supervise the generation of its own electricity using a jet-fuel powered stirling engine.

    Okay I'm interested in seeing this jet-fuel stirling engine. How well does it work in extreme cold?

    For those of you who may not know much about stirling engines, here's some information. [stirlingengine.com]

  • computer system that had to survive temperatures down to -85C

    Simple solution, just put a Pentium 4 Prescott in there. Keep the whole place nice and toasty.

  • Thanks to the excellent astronomical seeing conditions at Dome C, the Australian scientists started work on their second paper:

    "Quasi-Formulaic Investigations into the Space-Time Arrival Calculations of the Zarlanian Horde"

    The paper is being rushed to press with journals such as Nature and New Scientist in the hopes of beating the inevitable alien invasion and, thus, enjoying the publicity prior to enslavement and/or annihilation.

    "We're pretty excited about this second research opportunity. As soon as w
  • by Anonymous Coward on Wednesday September 15, 2004 @05:33PM (#10260323)
    The last question in TFA:

    Can you tell us about the dramatic events of 17 May 2004?

    By 17 May 2004 the AASTINO had worked remotely for 100 days in 2004, and then something went wrong...

    The WhisperGen engine has a control panel connected to it using an RS-485 bus running on CAT-5 cable. The control panel contains a microprocessor, and the engine expects to communicate with it regularly (at least once a second). When this communication is interrupted, the engine shuts down and reboots its own microprocessor.

    Unfortunately, this is what happened on 17 May. - the engine went into a cycle of rebooting every 40 seconds. Once the engine has stopped, we had a ten hour window in which to try to restart it before the 200AH lead-acid batteries would lose too much capacity and become too cold for a restart (which requires 15A at 24V for about 15 minutes).

    During this period we worked feverishly to come up with a solution. Our first priority was to shut down all unnecessary power consumption in the AASTINO - we can do this via a series of Dallas one-wire switches which control power to all the subsystems. A call to the engine manufacturer came up with the suggestion that we wiggle the CAT-5 cable connection - we suspect they forgot that we were over 4000 km away from our engine!

    The PC/104 computer was also on the RS-485 bus, and we reasoned that by rewriting the Linux device driver (which we had written in the first place, so we knew what we were doing) we could make the computer impersonate the control panel, and convince the engine that it should keep running. Fortunately, we had a snapshot of the communication traffic between the engine and the control panel from earlier testing in the lab with the manufacturer's MSDOS-based software. But with no hardware available to test our code, we had to modify the driver, send patches over the 2400 baud Iridium link, and rmmod/insmod the driver to try to restart the engine.

    All the while, the internal temperature of the AASTINO was plumetting towards ambient, at about -60C. We first modified the driver to allow the link traffic to be analysed, and this confirmed the communication problem with the control panel. After several attempts at generating fake packets from the control panel, punctuated by breaks in the Iridium link and agonizing waits for the system to redial (it is dialout only, controlled by a crontab entry), we were unable to prevent the engine from rebooting.

    We watched helplessly as the battery temperatures sank below the minimum threshold for engine restart. Over the next 24 hours we received the occasional connection from the AASTINO computer, but that was all. We are now hoping that the solar panels will be able to recharge the batteries suffiently to re-establish communication before the Dome C station opens for the summer.

  • Take a big circular dish, put mercury in it, spin it around on its central axis. If you do that at the South Pole with enough curvature in the resulting mercury pool, you might be able to take in a really large portion of the sky with fantastic light gathering capability. Asteroid hunting would be a snap. This would miss the equators of course, and a lot of the asteroids are associated with the Zodiac, but it would be a very cheap way of gathering data from a very remote location with good "eyes".

    Probl

    • Freezing point of mercury is -38C (which is just about -38F) ... so it would be solid through much of the Antarctic winter.

      When I froze mercury in the lab, it made a surface that wasn't optically useful -- lots of tiny bumps.

      Also of interest: the century old Mt. Wilson 100-inch telescope used mercury bearings for the polar axis. In the 1970's, mercury pollution worried the operations staff; I don't know what was done about it.
  • by modus ( 122983 ) on Wednesday September 15, 2004 @07:15PM (#10261171)
    You can view the health reports (temperature etc.) that that telescope sent back via Iridium here [unsw.edu.au].

    There may be other tasties too -- I haven't dug too much.

The Tao is like a glob pattern: used but never used up. It is like the extern void: filled with infinite possibilities.

Working...