When the National Aeronautics and Space Administration’s (NASA) spacecraft New Horizon made its first close encounter with Pluto on 14 July 2015, it was the first time the world saw what the planet looked like.
The Commonwealth Scientific and Industrial Research Organisation (CSIRO)’s Canberra Deep Space Communication Complex (CDSCC) played an integral role in that mission, as it was responsible for delivering the first close-up high resolution pictures of Pluto.
The CDSCC, located in Tidbinbilla, just outside Australia’s capital city, celebrates its 50th anniversary this year, and is part of NASA’s Deep Space Network. It is one of three tracking stations in the world that provides continuous, two-way radio contact with spacecraft exploring the solar system. The complex’s sister stations are located in Goldstone, California and near Madrid, Spain.
CDSCC director Ed Kruzins said each station is approximately 120 degrees longitude apart, but with CDSCC located on the southward facing side of the earth, it has a better view of the lower part of the solar system than the northern hemisphere, where the other two stations are located.
Together, the three stations provide around the clock tracking of 40 spacecraft, including missions studying almost every planet of the solar system, comets, the moon, and sun.
Onsite at the CDSCC, there are currently four antennas in operation: a 70-metre antenna, the largest of the lot and the biggest in the southern hemisphere, and three 34-metre dishes, while a fourth 34-metre antenna is currently under construction.
Kruzins said when the cost of running the 70-metre antenna becomes unmanageable one day, the 34-metre dishes will replace the aperture of the large antenna.
“The important thing for us is to have a highly reliable system, and we have a program of planned and corrective maintenance to make sure the antennas are running perfectly,” he said.
“Having said that, it doesn’t always run perfectly; antennas are very complex precision systems and sometimes electronically or mechanically, but we got it fixed and it’s back online. We have a pretty JPL enviable benchmark of 99.77 percent capture of signals.”
The antennas are used to send and receive data, and transmit scheduled commands to the spacecrafts on deep space missions. Kruzins explained the complex’s communication with each spacecraft works around a coordinated schedule set out by NASA’s Jet Propulsion Laboratory (JPL) located in Pasadena, California.
“We’re a bit like being part of a switchboard, or an air traffic control in the sky but in space. We control the spacecraft based on information that is given to us by the Jet Propulsion Laboratory, we work out where they are, so we have a navigation routine, and we take the data down,” he said.
He went on saying the schedules developed by JPL are based on computer predictions of each spacecraft’s location, and suggestions of how CDSCC should configure its antennas’s radio frequency accordingly.
“We get our share of [the schedule] and JPL will request us to work through this, and they work it out based on the position of our station, the position of the satellite, and whether the mission is routine or not. If it’s a non-routine mission then it gets a high priority, like a launch or encounter like New Horizons, which was supported by two CDSCC antennas for three days.
“If it’s a spacecraft emergency, and sometimes that happens, we’ll swing the antennas to find out what’s wrong and send the appropriate JPL commands to make sure it’s fine.”
When the raw data is transmitted from the spacecraft, CDSCC collects it, processes it, and share the information with JPL, before scientists deconvolve the data into images, Kruzins said.
CDSCC went through this process during the initial close encounter of Pluto by New Horizons. Kruzines said New Horizons is expected to send back 50GB of high-resolution images over the next 18 months.
“We’re taking data at roughly a rate of 1.2 kb per second, which is about 10,000 times slower than your internet at home. Why is it so slow? Because it’s so far away…[and] we don’t want to generate errors when we do that. If we go faster, we generate data bit errors, and the pictures will look pixelated or errenous,” he said.
But the Pluto mission is not the only thing keeping the CDSCC on constant monitoring duty. Since launching Voyager 1 and 2 into space 38 years ago for the grand tour of the solar system, where Voyager 2 headed south and Voyager 1 headed north, CDSCC is now the only station that has any contact with the Voyager 2 spacecraft.
“It’s because of where we’re located and because we have a large antenna that is big enough to be able to hear it in the southern hemisphere. The data we have received over the last three years has confirmed that the spacecraft has passed out of the solar system and truly into stellar space,” he said.
Tracking Voyager 2 has since enabled scientists to learn about the size of the solar system boundary or its heliopause, and the distance it takes to reach truly interstellar space from the Sun, Kruzins said.
Other missions on the radar for CDSCC include tracking the Dawn spacecraft that is on a mission of orbiting the dwarf planet Ceres, and the Mars Odyssey and Reconnaissance Orbiter, which are currently searching for the markers for life on the red planet. Information is also being drawn directly from the two rovers on Mars, Opportunity and Curiosity.
But not only is the CDSCC drawing information from planetary missions, Kruzins said the complex is also tracking Kepler, the space observatory on a mission to discovering planets around other stars. He said so far nearly 2,000 of the 3,500 planets indicated by Kepler to date have been confirmed.
The team behind running the 24-hour, seven days a week operation at the complex are classed into three groups, Kruzins said. He said there are the operators that drive the antennas to do the work; the maintenance people who make sure the antennas function normally, and that ranges from electricians to antenna mechanics; and people in service who make sure things run on budget and ensures the complex runs well, almost like a village.
“I think we’ve been involved in every major encounter that has ever happened around a planetary body in the solar system, and there’s more to come,” said Kruzins.