Target Pillar: Key Milestones in the History of Space Exploration
Last Updated: August 21, 2026 Author: Sarah Mitchell
Introduction
Voyager 1 and Voyager 2 launched in 1977, built to study Jupiter and Saturn on a mission originally planned to last a few years. Both spacecraft are still operating today, in 2026 — nearly half a century later, farther from Earth than any human-made object has ever traveled, and still returning genuine scientific data from a region of space no other spacecraft has ever reached.[^1] Keeping them alive this long hasn’t happened by accident. It’s the result of increasingly creative NASA engineering, executed in real time, to squeeze a few more years out of hardware never designed to survive this deep into the 21st century.
Where the Voyagers Actually Are
As of NASA’s most recent published figures, Voyager 1 sits more than 15 billion miles (25 billion kilometers) from Earth, and Voyager 2 is over 13 billion miles (21 billion kilometers) away — figures that continue increasing, since both spacecraft remain in motion, traveling at roughly 34,000 to 35,000 mph relative to the Sun.[^2][^3] Both are classified by NASA as being in interstellar space, having crossed the heliopause — the boundary of the heliosphere, the Sun’s protective bubble of solar wind particles and magnetic fields that shields the solar system from the wider galactic environment.[^4] Voyager 1 crossed that boundary in 2012; Voyager 2 followed in 2018, crossing at approximately 119.7 astronomical units from the Sun.[^1][^4]
No other human-made spacecraft has operated in interstellar space.[^2] That distinction is precisely why NASA has gone to such lengths to keep the Voyagers alive well past any originally planned mission duration — their instruments are collecting data from a region of space that literally nothing else has ever measured directly.
Why They’re Running Out of Power
Both spacecraft are powered by radioisotope thermoelectric generators (RTGs), which produce electricity from the natural radioactive decay of onboard plutonium — a power source that doesn’t depend on sunlight, which is essentially nonexistent at the Voyagers’ current distance from the Sun.[^5] The tradeoff is that RTG output inevitably declines over time as the radioactive material decays, and NASA reports each spacecraft loses about 4 watts of available power every year.[^6] After 47 years, that steady, unavoidable decline has left both Voyagers with only a fraction of their original electrical capacity — not a sudden failure, but a slow, entirely predictable squeeze that NASA has had to manage proactively for years.
The “Big Bang”: A Genuinely Clever Fix
In 2026, NASA engineers at the Jet Propulsion Laboratory executed a particularly inventive intervention on Voyager 2, nicknamed the “Big Bang.” The team switched off selected onboard powered devices and replaced their functions with lower-power alternatives, freeing up enough electricity to keep all three of Voyager 2’s remaining science instruments operating for at least another year — power that would otherwise have required shutting down an additional instrument before the end of 2026.[^7] Kareem Badaruddin, Voyager mission manager and systems engineer at JPL, described the team’s relief after the switch-off command executed without incident: “I don’t want to jinx it, but this ‘big bang’ test has gone remarkably smoothly. Voyager 2 — we’re done, and it went exactly to plan.”[^8]
Before greenlighting the change, engineers spent May and June 2026 running detailed power and thermal tests on Voyager 2 to confirm the reconfiguration wouldn’t create new risks, before finally executing it in July.[^8] NASA has indicated plans to attempt the same procedure on Voyager 1 as well, with cautious hope that any resulting power savings might eventually allow the team to restore its previously disabled cosmic ray subsystem experiment.[^8]
This wasn’t NASA’s first resourceful power-saving move for the mission either. Back in 2023, engineers began tapping into a small reserve of backup power originally set aside for an onboard safety mechanism regulating spacecraft voltage — a move that, at the time, successfully postponed an instrument shutdown on Voyager 2 that would otherwise have been necessary before 2026.[^5]
What’s Already Been Turned Off, and What’s Still Running
Each spacecraft originally carried ten scientific instruments; both are now down to just a few active systems, having shed the rest gradually over decades as power reserves shrank.[^1] As of NASA’s latest published instrument status, Voyager 1 has its Cosmic Ray Subsystem switched off (since February 2025) but keeps its Low-Energy Charged Particles instrument, Magnetometer, and Plasma Wave Subsystem running. Voyager 2 mirrors this pattern in reverse: its Low-Energy Charged Particles instrument is off (since March 2025), while its Cosmic Ray Subsystem, Magnetometer, and Plasma Wave Subsystem remain active.[^9] Both spacecraft’s imaging cameras and several other instruments were powered down years earlier, back in the late 1980s and 1990s, once their primary planetary flyby science was complete and their power was needed elsewhere.[^9]
With the 2026 power-saving measures in place, NASA now believes both probes could have enough electricity to continue operating with at least one functioning science instrument into the 2030s — though the agency is careful to caveat that projection heavily.[^1] As Voyager project scientist Linda Spilker put it: “Every minute of every day, the Voyagers explore a region where no spacecraft has gone before. That also means every day could be our last. But that day could also bring another interstellar revelation.”[^1]
Why This Mission Still Matters, Nearly 50 Years In
The Voyagers’ scientific legacy was already secure decades before their current interstellar work began. During their original planetary tour, they returned discoveries that fundamentally reshaped scientific understanding of the outer solar system — including active volcanoes on Jupiter’s moon Io, the first ever observed beyond Earth, revealing a solar system far more geologically dynamic than scientists had previously believed possible.[^5] Everything the Voyagers have measured since crossing into interstellar space is a genuine bonus beyond that original mission, data that literally no other instrument anywhere has ever collected, because no other spacecraft has traveled far enough to collect it.
Both spacecraft are set to reach their 50th anniversary in 2027, contingent on their aging nuclear power sources and fuel lines continuing to hold out against the extreme cold of deep space.[^10] Whatever their exact remaining lifespan turns out to be, the current chapter of the Voyager mission is, in a very literal sense, humanity’s most distant ongoing act of exploration — a pair of 1970s-era spacecraft, kept alive one clever power-saving trick at a time, still reporting back from farther away than anything else humans have ever built.
Frequently Asked Questions
How much longer will the Voyager spacecraft keep working?
NASA’s current projection, following 2026’s power-saving measures, is that both spacecraft could maintain at least one operating science instrument into the 2030s, though the agency is explicit that this is an estimate, not a guarantee — unforeseen hardware issues could shorten the timeline at any point.
Why don’t the Voyager spacecraft just run out of power and stop completely at some point?
They eventually will — their radioisotope thermoelectric generators produce steadily declining power as the onboard radioactive material decays, roughly 4 watts less per year for each spacecraft. NASA’s ongoing strategy has been to shut down individual instruments and non-essential systems progressively to keep at least some science capability running for as long as possible, rather than the entire spacecraft failing all at once.
What was the “Big Bang” maneuver NASA performed on Voyager 2?
It was a 2026 power-conservation maneuver where engineers switched off selected onboard powered devices and replaced their functions with lower-power alternatives, freeing up enough electricity to keep Voyager 2’s three remaining science instruments running for at least an additional year beyond what would otherwise have been possible.
Are the Voyager spacecraft the only human-made objects in interstellar space?
Yes, as of current NASA data — Voyager 1 and Voyager 2 remain the only spacecraft to have crossed the heliopause into interstellar space, having done so in 2012 and 2018 respectively.
What did the Voyager missions discover before reaching interstellar space?
During their original flybys of Jupiter, Saturn, Uranus, and Neptune, the Voyagers made numerous foundational discoveries, including the first confirmed active volcanoes beyond Earth, found on Jupiter’s moon Io — a finding that revealed the outer solar system to be far more geologically active and dynamic than scientists had previously understood.
Sources
- JPL/NASA — NASA Turns Off Two Voyager Science Instruments to Extend Mission
- NASA Science — Where Are Voyager 1 and Voyager 2 Now?
- ScienceDaily — NASA Shuts Down 49-Year-Old Voyager 1 Instrument to Keep It Alive
- Aerospace Global News — Where Is Voyager 2 Now? NASA Extends Interstellar Mission
- NPR — NASA Is Keeping Voyager 2 Going Until at Least 2026 by Tapping Into Backup Power
- JPL/NASA — NASA Turns Off Two Voyager Science Instruments (power decline rate)
- Aerospace Global News — Where Is Voyager 2 Now? (the “Big Bang” maneuver)
- Time News — NASA Maneuver Extends Voyager 2 Mission Beyond 2026
- NASA Science — Where Are Voyager 1 and Voyager 2 Now? (instrument status table)
- Time News — NASA Maneuver Extends Voyager 2 Mission Beyond 2026 (50th anniversary outlook)
Note on methodology: this article reflects NASA/JPL’s own published mission status pages and August 2026 reporting on the “Big Bang” power-saving maneuver. Voyager mission status changes frequently as power management decisions are made — consult NASA’s Voyager mission pages directly for the current instrument and position status.