50 Years Later, This Apollo-Era Antenna Still Talks to Voyager 2

For greater than 50 years, Deep Space Station 43 has been a useful software for area probes as they discover our photo voltaic system and push into the past. The DSS-43 radio antenna, positioned on the Canberra Deep Space Communication Complex, close to Canberra, Australia, retains open the road of communication between people and probes throughout NASA missions.

Today greater than 40 p.c of all knowledge retrieved by celestial explorers, together with Voyagers, New Horizons, and the Mars Curiosity rover, comes by DSS-43.

“As Australia’s largest antenna, DSS-43 has provided two-way communication with dozens of robotic spacecraft,” IEEE President-Elect Kathleen Kramer mentioned throughout a ceremony the place the antenna was acknowledged as an IEEE Milestone. It has supported missions, Kramer famous, “from the Apollo program and NASA’s Mars exploration rovers such as Spirit and Opportunity to the Voyagers’ grand tour of the solar system.

“In fact,” she mentioned, “it is the only antenna remaining on Earth capable of communicating with Voyager 2.”

Why NASA wanted DSS-43

Maintaining two-way contact with spacecraft hurtling billions of kilometers away throughout the photo voltaic system is not any imply feat. Researchers at NASA’s Jet Propulsion Laboratory, in Pasadena, Calif., knew that communication with distant area probes would require a dish antenna with unprecedented accuracy. In 1964 they constructed DSS-42—DSS-43’s predecessor—to help NASA’s Mariner 4 spacecraftbecause it carried out the first-ever profitable flyby of Mars in July 1965. The antenna had a 26-meter-diameter dish. Along with two different antennas at JPL and in Spain, DSS-42 obtained the primary close-up photos of Mars. DSS-42 was retired in 2000.

NASA engineers predicted that to hold out missions past Mars, the area company wanted extra delicate antennas. So in 1969 they started work on DSS-43, which has a 64-meter-diameter dish.

DSS-43 was introduced on-line in December 1972—simply in time to obtain video and audio transmissions despatched by Apollo 17 from the floor of the moon. It had higher attain and sensitivity than DSS-42 even after 42’s dish was upgraded within the early Nineteen Eighties.

The hole between the 2 antennas’ capabilities widened in 1987, when DSS-43 was geared up with a 70-meter dish in anticipation of Voyager 2’s 1989 encounter with the planet Neptune.

DSS-43 has been indispensable in sustaining contact with the deep-space probe ever since.

The dish’s dimension isn’t its solely exceptional function. The dish’s producer took nice pains to make sure that its floor had no bumps or tough spots. The smoother the dish floor, the higher it’s at focusing incident waves onto the sign detector so there’s a better signal-to-noise ratio.

DSS-43 boasts a pointing accuracy of 0.005 levels (18 arc seconds)—which is necessary for guaranteeing that it’s pointed immediately on the receiver on a distant spacecraft. Voyager 2 broadcasts utilizing a 23-watt radio. But by the point the alerts traverse the multibillion-kilometer distance from the heliopause to Earth, their energy has pale to a stage 20 billion occasions weaker than what is required to run a digital watch. Capturing each little bit of the incident alerts is essential to gathering helpful info from the transmissions.

The antenna has a transmitter able to 400 kilowatts, with a beam width of 0.0038 levels. Without the 1987 improve, alerts despatched from DSS-43 to a spacecraft venturing exterior the photo voltaic system probably by no means would attain their goal.

NASA’s Deep Space Network

The Canberra Deep Space Complex, the place DSS-43 resides, is one in every of three such monitoring stations operated by JPL. The different two are DSS-11 on the Goldstone Deep Space Communications Complex close to Barstow, Calif., and DSS-63 on the Madrid Deep Space Communications Complex in Robledo de Chavela, Spain. Together, the amenities make up the Deep Space Network, which is the most delicate scientific telecommunications system on the planet, based on NASA. At any given time, the community is monitoring dozens of spacecraft finishing up scientific missions. The three amenities are spaced about 120 levels longitude aside. The strategic placement ensures that because the Earth rotates, at the least one of many antennas has a line of sight to an object being tracked, at the least for these near the aircraft of the photo voltaic system.

But DSS-43 is the one member of the trio that may keep contact with Voyager 2. Ever since its flyby of Neptune’s moon Triton in 1989, Voyager 2 has been on a trajectory beneath the aircraft of the planets, in order that it not has a line of sight with any radio antennas within the Earth’s Northern Hemisphere.

To make sure that DSS-43 can nonetheless place the longest of long-distance calls, the antenna underwent a spherical of updates in 2020. A brand new X-band cone was put in. DSS-43 transmits radio alerts within the X (8 to 12 gigahertz) and S (2 to 4 GHz) bands; it may well obtain alerts within the X, S, L (1 to 2 GHz), and Okay (12 to 40 GHz) bands. The dish’s pointing accuracy additionally was examined and recertified.

Once the updates had been accomplished, take a look at instructions had been despatched to Voyager 2. After about 37 hours, DSS-43 obtained a response from the area probe confirming it had obtained the decision, and it executed the take a look at instructions with no points.

DSS-43 remains to be relaying alerts between Earth and Voyager 2, which handed the heliopause in 2018 and is now some 20 billion km from Earth.

[From left] IEEE Region 10 director Lance Fung, Kevin Furguson, IEEE President-Elect Kathleen Kramer, and Ambarish Natu, previous chair of the IEEE Australian Capital Territory Section on the IEEE Milestone dedication ceremony held on the Canberra Deep Space Communication Complex in Australia. Furguson is the director of the complicated.Ambarish Natu

Other necessary missions

DSS-43 has performed an important position in missions nearer to Earth as nicely, together with NASA’s Mars Science Laboratory mission. When the area company despatched Curiosity, a golf cart–dimension rover, to discover the Gale crater and Mount Sharp on Mars in 2011, DSS-43 tracked Curiosity because it made its nail-biting seven-minute descent into Mars’s ambiance. It took roughly 20 minutes for radio alerts to traverse the 320-million km distance between Mars and Earth, after which DSS-43 delivered the excellent news: The rover had landed safely and was operational.

“NASA plans to send future generations of astronauts from the Moon to Mars, and DSS-43 will play an important role as part of NASA’s Deep Space Network,” says Ambarish Natu, an IEEE senior member who’s a previous chair of the IEEE Australian Capital Territory (ACT) Section.

DSS-43 was honored with an IEEE Milestone in March throughout a ceremony held on the Canberra Deep Space Communication Complex.

“This is the second IEEE Milestone recognition given in Australia, and the first for ACT,” Lance Fung, IEEE Region 10 director, mentioned throughout the ceremony. A plaque recognizing the know-how is now displayed on the complicated. It reads:

First operational in 1972 and later upgraded in 1987, Deep Space Station 43 (DSS-43) is a steerable parabolic antenna that supported the Apollo 17 lunar mission, Viking Mars landers, Pioneer and Mariner planetary probes, and Voyager’s encounters with Jupiter, Saturn, Uranus, and Neptune. Planning for a lot of robotic and human missions to discover the photo voltaic system and past has included DSS-43 for important communications and monitoring in NASA’s Deep Space Network.

Administered by the IEEE History Center and supported by donors, the Milestone program acknowledges excellent technical developments all over the world. The IEEE Australian Capital Territory Section sponsored the nomination.