Voyager 1 Reactivates Thrusters After Decades of Silence

Voyager 1 Fires Engines at 24 Billion km with 23 Watts

The Voyager 1 probe, launched in 1977 and now about 24 billion kilometers from Earth, has activated thrusters that have been unused for decades. The goal is not to move faster, but something much more prosaic: keeping the antenna pointed at us. The news, reported by CNN en Español, was received with more frowns than enthusiasm. And that is where the trouble begins.

What Voyager 1 Activated and Why

The spacecraft has three sets of thrusters: two for attitude control and one dedicated to trajectory correction maneuvers. This is why some people put their hands to their heads when reading "thrusters" and thinking of a movie rocket engine. It is not that. Attitude control is the maneuver that orients an object relative to a reference system, and in a probe, it means, basically, turning the parabola so that Earth falls within the beam.

Hence the most repeated question: if the probe reached its estimulante ilegal years ago and in a vacuum there is no friction to slow it down, why activate anything? The short answer is that it is not activated to accelerate, but to reposition. And here is the fine detail: some argue that moving an antenna with precision of fractions of a millimeter requires mechanisms without real friction, impossible tolerances, and temperature margins that the electronics from half a century ago should not withstand. The breakdown of the link, with antenna gain and signal density, is enough for an entire notebook.

How a 23-Watt Signal is Received at 24 Billion km

Voyager 1's transmitter operates around 23 watts, the power of a modest light bulb. Upon arriving here, the signal is less than an attowatt, that is, one quadrillionth of a watt. We receive it with the Deep Space Network, 70-meter antennas that have been listening to the same point in the sky for decades. The signal is concentrated in a main lobe and transmitted with minimum bandwidth to improve the signal-to-noise ratio.

This is the argument that disarms part of the skepticism and fuels the rest. Because if the physics checks out on paper, everyday experience says otherwise: the slightest thing, the mobile phone loses coverage. The most common comparison is with terrestrial links, capable of covering about 200 kilometers with huge antennas and plenty of electricity; doing so at 24 billion kilometers with two objects in relative motion seems a different league. In contrast, the technical defense is simple: radio frequency technology has not changed so much, what changes is the gain, patience, and signal-to-noise ratio.

Fuel, Gyroscopes, and Failing Memory

It is worth remembering that the probe has no solar panels: its energy comes from a plutonium nuclear generator, and its computer has given scares, with corrupted memory that forced system resets and sent meaningless data for a time. Some point out that the gyroscopes do not function permanently and depend on lubricants that have been in a radiation environment for half a century. That orientation relies on observing the Sun and stars is, in that context, almost artisanal.

Here appears a curiosity that often falls into oblivion: the term attitude control did not originate in the space race, but in aviation, with the artificial horizon that allowed pilots to know if they were upright or upside down without seeing the ground. One of its promoters was Commander James H. Doolittle, the same one from the first bombing on Japanese soil in World War II. Half a century before a probe at 24 billion kilometers needed to turn its head.

From Technical Doubt to "It's All a Setup"

The conversation divides into three very different currents. One doubt from professional experience: those who have assembled microwave links or satellite dishes know that orienting an antenna well is demonic, and they transfer that intuition to a scenario a thousand times greater. Another argues that the matter is elementary physics poorly explained by the media, starting with translations and terms that no one bothers to clarify. And a third jumps directly to total skepticism: if that is impossible, then the entire space program is a set, including the 1969 moon landing.

The clash has a layer that almost no one disputes: we are all laymen in almost everything and end up believing or not believing, which is not the same as knowing. The uncomfortable question is how many of those who sign the condemnation would be able to verify a single piece of data. And the symmetric: how many of those who agree could explain how to discriminate an attowatt signal from background noise.

The fact is that the probe is still there, with its 1.4-meter antenna, its 23 watts, and a signal that takes about 23 hours to arrive. Operating with 1977 spare parts and a dose of luck that, for more than one in the thread, borders on the irrational. How much of what we call scientific certainty is, in reality, confidence in who tells us?