Only two spacecraft manufactured by humans are currently journeying through the vastness of interstellar space, and their fuel reserves are dwindling.

**Voyager 1**, which was launched in 1977 and is now over 15.6 billion miles away from Earth, initially housed 10 scientific instruments. However, after **NASA** recently turned off another device to preserve its limited nuclear fuel, only three are still functional. This month, engineers will also deactivate an instrument on **Voyager 2**, the counterpart exploring space.

*”Since their launch, the Voyagers have been the stars of deep space, and we want to maintain that status for as long as we can,”* stated Suzanne Dodd, Voyager project manager at **NASA’s Jet Propulsion Laboratory**. *”However, our electrical power is diminishing. If we don’t disable an instrument on each Voyager now, they will likely have just a few more months of power before we have to announce the end of the mission.”*

With meticulous engineering and skilled troubleshooting, the Voyager probes may stay operational until the mid-2030s.

### Disabling for Sustainability

The latest instrument to be switched off is the **cosmic ray subsystem experiment**, which analyzed high-energy atomic particles traveling through space, frequently generated by **supernova** explosions. This instrument was instrumental in verifying that Voyager 1 had crossed the **heliosphere**—the protective bubble of particles released by the **sun**—and had officially entered **interstellar space** in 2012.

Currently, Voyager 1 depends on three remaining instruments:
– **Magnetometer**
– **Plasma wave subsystem**
– **Low-energy charged particle instrument** (scheduled for shutdown in 2026)

The spacecraft’s **plutonium fuel supply** is gradually running out, with power output declining by approximately four watts each year. For context, a standard toaster consumes between 800 and 1500 watts, while each Voyager probe now produces only **249 watts**.

### The Final Stage

The mission of Voyager 1 will ultimately conclude when it lacks sufficient power to connect with **NASA’s Deep Space Network**, a vast system of large radio antennas distributed worldwide.

As the Voyager probes approach 50 years of deep space exploration, they have withstood harsh radiation and close encounters with icy planets. Their enduring functionality highlights their durable design and the commitment of **NASA engineers**, who have dedicated decades to keeping these aging spacecraft operational—often using vintage computer systems onboard these nearly 50-year-old probes.

*”The engineers deserve commendation,”* remarked Alan Cummings, a cosmic-ray physicist at **Caltech**, the institution overseeing **NASA’s Jet Propulsion Laboratory**.

Despite their diminishing power, the Voyager spacecraft persist in their extraordinary journey, transmitting humanity’s message into the immense unknown.