Voyager 1
A glitch aboard Voyager 1 prevented it from communicating with NASA for about a month. NASA

The Voyager 1 spacecraft, launched nearly 50 years ago and billions of miles out in space, began communicating with NASA again after a glitch prevented it from sending information for about a month.

Voyager 1, which has been exploring the solar system since 1977, suddenly shut down its primary radio, called an X-band transmitter, and activated a weaker S-band transmitter that hadn't been used since 1981, NASA said.

That switch and its distance from Earth, about 15.4 billion miles, prevented engineers from downloading data and information from the probe. The flight team learned of the problem when it couldn't detect a signal from Voyager 1 on Oct. 18.

An engineering team was able to reactivate the X-band transmitter, allowing them to receive information from the spacecraft again last week.

"Now engineers are completing a few remaining tasks to return Voyager 1 to the state it was in before the issue arose, such as resetting the system that synchronizes its three onboard computers," NASA said.

The space agency said the X-band transmitter had been shut down by the probe's protection system when engineers turned on a heater on the spacecraft.

The network is designed to shut down some operations not essential to flying when it detects that Voyager 1 has lost power to keep critical systems operating.

"But the probes have already turned off all nonessential systems except for the science instruments. So the fault protection system turned off the X-band transmitter and turned on the S-band transmitter, which uses less power," NASA said.

Voyager 1, which launched in September 1977, and Voyager 2, which launched in August 1977, are the only two spacecraft operating in interstellar space, and their ages have contributed to their technical problems according to NASA.