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The Planetary Society BlogBy Emily LakdawallaWelcome news on DSN upgradesFeb. 25, 2010 | 10:23 PST | 18:23 UTC
I've written before about a serious problem looming for planetary exploration: the aging infrastructure of NASA's Deep Space Network (DSN). It is through the giant radio dishes of the DSN -- 34 or even 70 meters across -- located in California, Spain, and Australia that we send orders to our distant spacecraft, and receive the volumes of data that they return to Earth. Missions to close destinations like the Moon don't need the DSN; Lunar Reconnaissance Orbiter, for instance, sends its Terabytes of data through a dedicated 18-meter-diameter antenna in New Mexico. But everything that travels beyond Earth orbit has to compete for precious time on those great DSN antennas.
So I was very happy to see today's press release from NASA, announcing that they were breaking ground on three, count them, three new 34-meter-diameter "beam wave guide" dishes at the DSN station in Canberra, Australia, which will be capable of operating in the Ka band. The "beam wave guide" part refers to five mirrors that bounce the radio signals from the dish down to a below-ground electronics room. So when these things need maintenance, the maintenance is performed inside a climate controlled, below-ground room rather than in the open air at altitude on an enormous dish -- something that will make maintentance and upgrading faster, easier, and cheaper. The 34-meter antennas can be used in concert, as an array, to substitute for a 70-meter antenna; Cassini already does some of its communications using arrayed 34-meter antennas. Construction of the three new antennas is expected to be complete in 2018. Why are all three new antennas being built in Australia? Here's two slides from a February 2009 presentation by DSN program manager Michael Rodrigues (PDF format) that illustrate why this is necessary.
Infrastructure upgrades are never sexy projects; it's like replacing a highway bridge instead of building a new sports stadium. But the DSN antennae are our bridges to our robotic spacecraft; it would be all too easy to take the DSN for granted until we wake up one morning to discover that a catastrophic failure has rendered us unable to get hard-won data back from space. I am sure that today's announcement covers just one line item from a whole laundry list of upgrades that are needed at the three DSN stations. I'm not exactly sure how to advocate for better support of the DSN, except by writing about it here. To all the folks who keep those giant dishes running, a hearty thanks! Without you we'd never be able to see the distant wonders of our solar system.
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That answers my question about whether a 34m is really a replacement for the 70m, I think. They're not, not entirely. But they hope to have lots more scheduled downtime.
Are there any plans on constructing similar antennas in South America (or South Africa)? That would be a huge and costly effort, but it would be worthwhile, wouldn't it?
"Infrastructure upgrades are never sexy projects; it's like replacing a highway bridge instead of building a new sports stadium."
Sorry, I'm sure you got it wrong there: I can't begin to imagine how any infrastructure could be more boring than a sports stadium. A bridge, on the other hand, now that's sexy! ;)
Hints at a third are on the horizon, but one important factor is that this upgrade is also ultimately part of a plan to retire the 70-metre dishes by the mid-late 2020s.
http://www.esa.int/esaCP/SEM6Y71P0WF_index_0.html
and
http://www.esa.int/esaMI/Operations/SEM7XQFWNZF_0.html
ESA's first and second DSA-antennas are already operational. They are placed in New Norcia (Western Australia) and Cebreros (Spain), respectively.
All three antennas have or will have 35m diameter and beam-wave guide system with a frequency-sensitive (dichroic) mirror and S- and X-band feeds, cryogenically cooled S- and X-band low-noise amplifiers and 2- and 20-kilowatt S- and X-band transmitters.
There are plans to outfit the stations for data reception in the Ka-band (32 GHz), which will become the future international standard for deep-space missions.