THE CSIRO’S LATEST RADIO TELESCOPE—the Australian Square Kilometre Array Pathfinder, or ASKAP—is now taking shape in the remote Western Australian desert.
When completed in 2012 it will comprise 36 dishes all acting in concert to produce the same result as one big dish. Cutting-edge receiver technology invented by CSIRO scientists will give it an extremely wide field of view. This, coupled with high-speed electronics and an ultra-fast optical fibre link to a dedicated computing centre in Perth, will make ASKAP arguably the best radio telescope system in the world.
ASKAP’s first five years of observations are already booked out by teams from around the world, and the science studies it will tackle are some of the biggest around—how did the earliest stars and galaxies form; how have galaxies evolved through time; what role has magnetism played in the cosmos; and can Einstein’s theories stand ever-more stringent tests?
ASKAP is also the Australian and New Zealand “pathfinder” for the ultimate prize—the Square Kilometre Array, or SKA. The SKA will be a vast collection of thousands of dishes and antennae spread across an area the size of a continent. A decision will be made next year by an international committee, as to whether the SKA will be hosted in Australia-New Zealand or southern Africa. The linked telescopes will make images ten times more detailed than those of the Hubble Space Telescope.
SpaceInfo.com.au wanted to get an update on progress with ASKAP, so we spoke to the man in charge—ASKAP Project Director Antony Schinckel, of CSIRO’s Astronomy and Space Science division—to find out how things are going in the WA desert:
Can you give us a rundown on the state of construction of ASKAP?
We’re very happy with how things are going—we’re at the point where there is substantial activity on site. Major infrastructure construction commenced in May. The first phase of that was that the company doing the work needed to put in their temporary accommodation camp, as there are no motels for hundreds of kilometres!
Between now and early December we’ll complete all of the 30 remaining antenna foundations, the access tracks to each antennae, fibre and power distribution around the site and to each antenna, and then the central building as well—all of the primary infrastructure that doesn’t include the science instruments and power systems.
It must be a difficult task, building hi-tech facilities that are essentially in the middle of nowhere?
With these remote sites there are a lot of logistics that need to be understood and got moving properly, but the contractors have a fair bit of experience with that. Most of it is normal civil engineering, although there are a few subtleties—for instance, the concrete foundations for the antennae need to be a certain minimum stiffness.
The unusual bits in a sense are the optical data fibre links between the antennae and the central site. Our raw data rate will be phenomenally high, about 74 terabits per second for the total 36 antennae. That data then goes into some special equipment (the beam former and the correlator) which ramps down the rate fairly significantly before it is sent via cable down to Perth.
How are you going to handle the enormous amounts of data produced by the 36 ASKAP antennae?
Well, it’s going to be a really interesting challenge how we treat this. We can’t afford to archive the absolute raw data—the volume is just too high. So working out which are the critical data products to archive right up front is going to prove a real challenge. We’ve clearly got some plans on which ones are the most important, but it’ll be fascinating to see over the next few years if we end up archiving those or finding we have to modify it a little bit.
The Pawsey Centre in Perth is a key part of this in terms of the data reduction.
The actual fibre in the ground that CSIRO has put in, is through a contract with AARNet with major sub-contracts to CCTS and North Coast Holdings, out of Geraldton. The fibre has now been fully laid and tested. The fibre is all buried, which is easier long term than having it up on aerial poles. The fibre is better protected when buried. There are three booster huts along the length of the fibre.
There are two remote booster huts that are solar powered with the possibility of back-up diesel if required. And there’s one in the town of Mullewa, which is just on grid power with back-up.
As far as terrain goes, there’s a gentle slope 350km up from Geraldton to the site—we end up at an elevation of about 370 metres.
How will you supply electrical power to such a remote site?
With power, our intention long-term is to have as a renewable a power source as we possibly can. For all sorts of obvious reasons, we want to go with generating most of our power through whatever renewable resources we have. Out in that region of Western Australia in particular, solar power is extremely attractive. It’s one of the places with the highest solar insolation in the world. So solar will be a substantial part of it.
To begin with we’ll have a base power capability from diesel generators, but over a number of years we’ll be expecting to be adding or start off with some solar on top of the diesel, and then in a couple of more years we have some additional funds that will enable us to expand that significantly around 2013-14.
Power storage is something of an issue. That’s partly why we’ve put the funding back a couple of years, to see what eventuates with power storage options by the time ASKAP is really up and operational. The focus now is on what we need to get it going.
You have six dishes installed and two more being installed right now. What’s the schedule for the rest of them?
It’s a fairly continuous process of installing the remaining antennae right through this year and into early 2012, at about 3 to 4 per month. A team from the Chinese manufacturer, CETC54, comes out to supervise their construction.
With the dishes, there’s one point there that we’ve been particularly thrilled with. We specified a surface accuracy of 1mm but the delivered capability substantially exceeds that—most of the antennae are coming in with an accuracy of about 0.5mm. This means in the long-term they could be used to do observations at much higher frequencies than originally planned, giving us very good long-term flexibility.
Another thing that CETC54 has achieved is that we don’t have to adjust the surfaces. They’ve come up with a manufacturing technique in China and then at installation here that means it’s literally a case of just bolting the dish panels together … there’s no fine adjustment necessary here in Australia.
Given that it is such remote site, will there be people stationed there on a regular basis?
No, not for operations. Like most telescopes these days, it can be operated by remote control from anywhere. However, with an array as big and as complex as this—36 antennae, vast data rates, these huge specialised digital systems—it really is a dramatic step forward. The telescope is about a factor of 10 more powerful than any other radio telescope in the world. So regular maintenance will be required to keep the system up and running, and there will be people going out to the site to do that.
Finally, from a personal standpoint, what’s it like to be out there in the WA desert? The conditions must be pretty challenging.
Many telescopes are built in remote sites, but mostly they’re built where there’s already some level of infrastructure. For us working out at Boolardy Station, you have to bring in absolutely everything. You know intellectually that that’s true, but nonetheless on the day when you realise you really do need that special screwdriver, you find it is 350km away! It’s one of those classics where you know philosophically how to do something, and you think you’ve got it covered…but boy, there really is no give and take on that.
Summers out there are pretty warm. We’ve managed to move schedules around to deal with that, and it’s quite manageable; it’s just a case of thinking things out sensibly. We’ve worked a lot with regional contractors in WA who are experienced at this and we’ve shifted our mindset to suit the climate.
The wildlife situation reminds us that we’re living in Australia. The numbers of kangaroos, emus, goannas and snakes, has been quite impressive. Snakes in particular are the most dangerous local wildlife, but we’ve got good procedures in place to deal with them.
Story by Jonathan Nally, SpaceInfo.com.au. Images courtesy CASS / Terrace Photographers / Paul Bourke and Jonathan Knispel (Supported by WASP (UWA), iVEC, ICRAR, and CSIRO).
Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz
Like this story? Please share or recommend it…