Posted on by Carolyn Collins Petersen

Oops. NASA Accidentally Points Voyager 2’s Antenna Away from Earth, Temporarily Losing Contact

It’s every space mission’s nightmare: losing contact with the spacecraft. In the best case, you recover it right away. Worst case, you never hear from your hardware again. On July 21, controllers lost contact with Voyager 2, out in the depths of space. Now they’re waiting for a reset to catch Voyager 2’s next message when it “phones home”. (Update: on August 2, NASA announced via its Twitter account that it has received a “heartbeat” carrier signal from the spacecraft.)

So, what happened? The spacecraft, which is nearly 20 billion kilometers away, seems to be doing fine. It’s probably sending all kinds of communications back to Earth. But, the stream of data is bounding off into space instead of linking up with the Deep Space network. That’s because a series of planned commands to Voyager 2 inadvertently caused the spacecraft to point its antenna 2 degrees away from Earth. Essentially, Voyager 2 and Earth are not in communication. They’re “talking past” each other.

This artist's concept depicts one of NASA's Voyager spacecraft, including its high-gain antenna. Voyager 2 is out of communications until October. Credit: NASA/JPL-Caltech
This artist’s concept depicts one of NASA’s Voyager spacecraft, including its high-gain antenna. The cosmic ray subsystem is highlighted, too. Voyager 2 is out of communications until October. Credit: NASA/JPL-Caltech

Regaining Contact with Voyager 2

All is not lost. Yet. That’s because the spacecraft is programmed to reset its orientation several times a year to keep the antenna pointed toward Earth. The next reset isn’t for several months—on October 15th. Until then, Voyager 2 is speeding along on its planned trajectory. If all goes well, the control team should hear from the spacecraft again on October 15th. At this point, they’re characterizing this loss of signal as a temporary communications pause. There’s nothing to indicate any other problems with Voyager 2, beyond the mistaken commands.

The spacecraft is equipped with a high-gain antenna measuring 3.7 meters across. It communicates with the Deep Space Network via the S band (13 cm wavelength) channel as well as in the X band (3.6 cm wavelength). At its current distance, the spacecraft’s signals take about 17.5 hours to get back to Earth. That time increases as the spacecraft gets farther away.

A Glorious History

Currently, Voyager 2 and its twin Voyager 1 are exploring space beyond the solar system. They launched in 1977 and for the past decades, they’ve made huge discovieres at planets and the outermost bounds of the heliosphere. Their images and data opened up a whole new way of looking at the outer solar system.

Now, they’re in the Voyager Interstellar Mission phase, where their data helps characterize the “limits” of the solar system lie and where deep space begins. Voyager 2 probably entered interstellar space a few years ago, although it still reports on conditions at the “edge” of the solar system. Interestingly, while Voyager 2 is out of communications with Earth, Voyager 1 is still talking with the Deep Space Network. It’s about 24 billion kilometers from Earth.

NASA's Voyager 2 Probe Enters Interstellar Space This illustration shows the position of NASA's Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto. Voyager 1 exited the heliosphere in August 2012. Voyager 2 exited at a different location in November 2018. Credit: NASA/JPL-Caltech
This illustration shows the position of NASA’s Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto. Voyager 1 exited the heliosphere in August 2012. Voyager 2 exited at a different location in November 2018. Credit: NASA/JPL-Caltech

Ultimately, they’re headed out on two very different trajectories through the stars. They have enough power to operate for a few more years (2025 or thereabouts) to send back information to Earth about their environments. Engineers on the project have figured out a way to extend spacecraft power for perhaps a couple more years by tapping some specific onboard reserves. Eventually, however, the spacecraft will fall silent as their power supplies run out. This current outage on Voyager 2 is giving mission engineers an early taste of what that experience will be like, after “talking” with these distant spacecraft for nearly five decades.

For More Information

Mission Update: Voyager 2 Communications Pause
Voyagers Mission Status

One Reply to “Oops. NASA Accidentally Points Voyager 2’s Antenna Away from Earth, Temporarily Losing Contact”

  1. I’m happy to report that Voyager 2 was early rescued and is now returning what appears to be our regular science data stream.

    “But on Tuesday, engineers enlisted the help of multiple Earth observatories that form the Deep Space Network (DSN) to detect a carrier or “heartbeat” wave from Voyager 2, though the signal was still too faint to read the data it carried.

    In a new update on Friday, NASA’s Jet Propulsion Laboratory (JPL), which built and operates the probe, said it had succeeded in a longshot effort to send instructions that righted the craft.

    “The Deep Space Network used the highest-power transmitter to send the command (the 100-kw S-band uplink from the Canberra site) and timed it to be sent during the best conditions during the antenna tracking pass in order to maximize possible receipt of the command by the spacecraft,” Voyager project manager Suzanne Dodd told AFP.

    This so-called “interstellar shout” required 18.5 hours traveling at light speed to reach Voyager, and it took 37 hours for mission controllers to learn whether the command worked, JPL said in a statement.

    The probe began returning science and telemetry data at 12:29 am Eastern Time on August 4, “indicating it is operating normally and that it remains on its expected trajectory,” added JPL.”

    [Phys.org, by Issam AHMED.]

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