Robotic Telescope Installed on Antarctica Plateau 128
Reservoir Hill writes "Antarctica claims some of the best astronomical sky conditions in the world — devoid of clouds with steady air that makes for clear viewing. The very best conditions unfortunately lie deep in the interior on a high-altitude plateau called Dome A. With an elevation of up to 4,093m, it's known as the most unapproachable point in the earth's southernmost region. Now astronomers in a Chinese scientific expedition have set up an experimental observatory at Dome A after lugging their equipment across Antarctica with the help of Australia and the US. The observatory will hunt for alien planets, while also measuring the observing conditions at the site to see if it is worth trying to build bigger observatories there. The observatory is automated, pointing its telescopes on its own while astronomers monitor its progress from other locations around the world via satellite link. PLATO is powered by a gas generator, and has a 4000-litre tank of jet fuel to keep it running through the winter. The observatory will search for planets around other stars using an array of four 14.5-centimetre telescopes called the Chinese Small Telescope Array (CSTAR). Astronomers hope to return in 2009 with new instruments, including the Antarctica Schmidt Telescopes (AST-3), a trio of telescopes with 0.5-metre mirrors, which will be more sensitive to planets than CSTAR."
Re:Interesting that robotic was the way to go here (Score:3, Informative)
Where human missions are useful is where the variables are not known. If you are not sure what will need to be done, or if depending on your initial finding the rest of the mission will change unpredictably, you need people in the loop. While the resources needed to get them there and keep them alive are initially higher than most robotic missions would be, having humans on the scene gives you far greater flexibility.
Re:14.5 centimeters? (Score:5, Informative)
Re:Interesting that robotic was the way to go here (Score:2, Informative)
some information on the computer control systems (Score:5, Informative)
As one of the University of New South Wales people involved, I thought slashdot might like some information on the computer systems that PLATO uses.
PLATO uses two redundant PC/104 form factor computers running Debian Etch. The computers boot from a 4GB flash disk (we tested 5 different models in the lab, and found one that worked reliably to -60C, despite only being spec'ed to -25C; all the other models worked to -40C, but had problems below that).
We use a readonly filesystem, with /home, /etc, and /var being created on boot in a ramdisk. This works really well, and it is nice to be able to turn off the power at any time without being concerned about filesystem corruption. Needless to say, with no possibility of any human being on-site for the rest of the year, we have thought very carefully about reliability.
Bulk data storage is provided by terabytes of conventional disks, with the most precious data being backed up on ~64GB of USB flash disks. Conventional disks don't handle the altitude very well, so we don't like to rely on them.
Communication is via two Iridium satellite modems, running at 2400 baud. We can push software updates by sending a set of "Short Burst Data" messages of up to 2000 bytes at a time. We can also login to PLATO using ssh, and I'm logged in as I'm typing this and running experiments.
There is a CAN (Controller Area Network) bus running throughout PLATO and linking the two modules: the Instrument Module, and the Engine Module, 45m apart. Each of 11 nodes on the bus has a small Atmel board that can turn power on/off to experiments, digital and analog I/O, etc.
More info, photos, and links to the health and status data are at http://mcba11.phys.unsw.edu.au/~mcba/plato [unsw.edu.au]
Re:Lots o' jet fuel (Score:5, Informative)
Actually, Dome A is one of the least windy places on Earth, typically just 2-3 metres per second. Dome A is the highest point in the centre of the Antarctic plateau, and this is where the katabatic winds start from. The winds accelerate as they head towards the coast, and that is where they can reach 100's of kph.
So, unfortunately, wind power was not feasible.
Re:Fantastic info - why is this not modded up? (Score:5, Informative)
With two modems going flat out we could theoretically transfer 40MB per day. In practice the link isn't all that reliable and we would be lucky to achieve half of that. Still, it is enough to control the experiments and return reduced data to verify that everything is working. All of the health and status information fits into 12KB per day.
The bulk of the data will be physically returned by the next Chinese traverse team, this time next year.
Re:Lots o' jet fuel (Score:3, Informative)
Re:some information on the computer control system (Score:5, Informative)
The engines are Hatz 1B30, we use two different generators: four are made by eCycle, and two by Mavilor. Each puts out about 1kW at 120VDC.
To start the engines we have two banks of Ultracapacitors. These are amazing devices, 3000 Farads each, charged to 2V, with 12 in each bank arranged to give 12VDC. They can turn over the engines very quickly. We haven't had to crank an engine for more than 2 seconds yet, although we haven't dropped the engine temperatures below 0C.
We tested the system in a pressure tank at UNSW to simulate the roughly 0.5atm pressure. The engines still work well at this altitude.
Re:Really cold (Score:1, Informative)
How PLATO got to Dome A (Score:5, Informative)
For your interest, here is some information on how PLATO got to Dome A.
The PLATO modules were built at the University of New South Wales in Sydney, Australia. Instruments were provided by our collaborators at a number of universities in China, the US, and the UK.
In late November 2007 PLATO was trucked 3912 km to Perth, where it joined a Chinese icebreaker for a two week trip to Zhongshan station on the edge of Antarctica. A helicopter then lifted the modules off the ship and about 100km inland where they joined a traverse for the ~1200 km journey to Dome A.
The traverse was an amazing feat. 17 people, 5 tractors. PLATO itself weighted about 10 tonnes. The traverse moves at speeds of 5-10 km per hour each day for 10 hours, and then rested for 14 hours. After three weeks of this, they arrive at Dome A. I am told that the undulating motion of the tractors over the ice can give you "sled sickness", an unpleasant variety of seasickness.
The team spent 10 days at Dome A, and did a fantastic job of installing the experiments and getting everything working. The temperatures were around -30C, which isn't much of an issue at low wind speeds. The altitude (4090m) is more of a problem, as it makes physical work exhausting, and there are difficulties with sleeping, mental acuity, etc.
Much more information, and a diary of the trip by the Chinese team members, is at http://mcba11.phys.unsw.edu.au/~mcba/plato [unsw.edu.au].
Re:Lots o' jet fuel (Score:5, Informative)
As for astronomy, the team running this automated experiment at Dome A did it previously at Dome C. I was on the first winterover team [gdargaud.net] in 2005 and monitoring the turbulence for astronomy was one of the main goals. Bigger telescopes are being installed as we speak in time for the start of the 4th winterover in a few days.
Dome A is 1000m higher than Dome C (4200m vs 3200m) but is even harder to reach and the temperature in winter borders on the insane: we had -78C during our winterover so I'll let you imagine at Dome A...
Re:Really cold (Score:4, Informative)
Diesels engines are what make power down there, because 1) the compression stroke does provide enough heat to ignite diesel-like fuels. 2) they're more efficient.
They use jet fuels because they're compatible with icing inhibitors--and proper diesel engines don't mind.
Re:some information on the computer control system (Score:5, Informative)
Has your team considered puting the hard drives in a pressure vessel of some sort?
Yes, we have thought about this a lot, and have never had the time to complete the design! It is the best solution, and we should be doing it. It is much easier nowadays that IDE interfaces are going away and serial connections mean that fewer cables need to leave the pressure vessel.
If we use a USB interface, I'm a bit nervous about the reliability of Linux USB storage, or perhaps it is the controllers that interface the drive with USB. I've had many examples of filesystem corruption with external USB drives. And USB flash disks seem to have problems too. Quite often during boot a drive will give all sorts of error messages and will require power cycling to fix it. Googling for these problems show that they are common, but with no solutions that I have found.
Our particular PC/104 computer has both USB 1 and 2 interfaces, but we can only boot reliably off USB 1, and we see intermittent failures if we use both USB 1 and 2. The flakiness of USB for storage is a major frustration.
SATA wasn't an option on our computer. These are low-power embedded systems, so they tend to lag a bit with some of the newer interfaces.