SwRI Forecasts New Horizons May Hit Termination Shock Between 2029 and 2040

Q: With next-gen power sources emerging, what mission will succeed New Horizons in exploring true interstellar space?

The most likely successor to New Horizons for pushing into true interstellar space is an **interstellar precursor mission** powered by the new **Next-Generation Radioisotope Thermoelectric Generator, or Next Gen RTG**. That answer follows directly from the latest deep-space planning around New Horizons. SwRI’s new work shows New Horizons may reach the termination shock between 2029 and 2040, but its aging power system could limit science returns by the time it approaches the heliopause in the 2040s. That makes a follow-on mission important if NASA wants dedicated measurements deeper into the heliosphere and beyond. The enabling technology is the Next Gen RTG being developed by L3Harris with the U.S. Department of Energy. The design was finalized in 2026, and the unit is intended to provide about 250 watts for spacecraft operating far from the Sun, where solar power is impractical. Reporting tied to that program says it is aimed at supporting outer solar system missions and **interstellar precursor missions beginning in the early 2030s**. In practical terms, that means the mission expected to succeed New Horizons is not a named replacement already flying, but a new class of **RTG-powered interstellar precursor probes**. These would be built to travel beyond the Kuiper Belt, cross the heliosphere’s outer boundaries with modern instruments, and continue into the local interstellar medium with better power margins than New Horizons.

2 articles · Updated · Universe Today · Jul 4

New Horizons could reach the termination shock as early as 2029 or as late as 2040, giving scientists a target window to prepare measurements at the heliosphere’s outer boundary.
SwRI researchers produced that forecast by combining solar-wind prediction methods with analytical and numerical heliosphere models, aiming to pinpoint the first plasma boundary along the probe’s path.
The team said the crossing may happen more than once because the heliosphere expands during solar maximum and contracts during solar minimum, shifting the boundary over time.
Two papers in The Astrophysical Journal and Advances in Space Research detail the work, which follows New Horizons’ 2019 Arrokoth flyby and supports planning for future missions probing interstellar space.

Sources

Universe Today17h ago

SwRI Develops Solar Wind Forecasting for New Horizons' Termination Shock Encounter

starshipinsider.com3h ago

Researchers develop solar wind forecasting method to locate outer heliosphere | Starship Insider

How will new solar wind data reshape our model of the heliosphere's dynamic and mysterious boundary?

With next-gen power sources emerging, what mission will succeed New Horizons in exploring true interstellar space?

As its nuclear battery fades, can New Horizons solve the mysteries of our solar system's edge before going silent?

Approaching the Termination Shock: New Horizons’ 2029–2040 Mission to Map the Heliosphere’s Boundary

Overview

New Horizons is steadily approaching the heliospheric termination shock, a dynamic boundary about 100 astronomical units from the Sun where the solar wind slows dramatically as it meets the interstellar medium, creating a shockwave. This region is crucial for understanding how our solar system interacts with interstellar space and how cosmic rays and energetic particles enter our system. By directly measuring this boundary, New Horizons will provide new insights into the structure and behavior of the heliosphere, helping scientists better understand the protective bubble around our solar system and informing future interstellar exploration.

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