The Space Show Presents Dr. Alan Stern, Friday, Aug. 28, 2026
Quick Summary
The Space Show featured Dr. Alan Stern discussing the New Horizons mission, its recent 11-month hibernation, and ongoing scientific activities in the outer solar system. Stern explained the mission’s budget constraints, which limit ground operations and data return, and the need for additional funding to keep heliospheric instruments running. He detailed the spacecraft’s current position, its study of the Kuiper Belt, and the search for a new flyby target using ground telescopes and the upcoming Roman Space Telescope. Stern shared new findings about Pluto, including evidence of liquid nitrogen flows, and highlighted the diversity of trans-Neptunian objects. The conversation also covered future propulsion technologies like nuclear thermal and fusion, their potential to revolutionize space travel, and the concept of a mission to intercept interstellar comets. Stern answered questions about spacecraft operations, instrument capabilities, and the challenges of deep space communication.
Detailed Summary
The Space Show welcomed listeners and introduced Dr. Alan Stern, the principal investigator of New Horizons, as the guest for the Friday Space Show. Alan explained that New Horizons hibernated for 11 months from August 2025 to June 2026, during which some subsystems were turned off while others, including three scientific instruments, recorded data continuously. He noted that hibernation was primarily due to budget constraints, as sufficient funding was not available to staff mission control year-round or operate all scientific instruments.
Our guest explained that New Horizons has three scientific instruments: a dust detector studying Kuiper Belt dust distribution, and two plasma spectrometers measuring the Sun’s outer heliosphere. The spacecraft can perform targeted flybys like the 2019 encounter with Arrokoth, with plans to search for another flyby target using ground-based telescopes and potentially the Nancy Grace Roman Space Telescope. Alan clarified that the mission’s operational lifespan is limited by the spacecraft’s nuclear power supply, which will lose power around 2050, rather than communication range issues, making it impossible to continue operations beyond that time.
Alan provided updates on New Horizons’ current position at 66 astronomical units from the sun and discussed the mission’s trajectory toward the galactic center direction, similar to the Voyagers but in the plane of the solar system. He explained that New Horizons will likely leave the Kuiper Belt within the next 7 years, depending on its extent, and shared recent discoveries about Pluto’s Sputnik Planitia glacier showing evidence of liquid nitrogen flow. Alan highlighted budget constraints affecting the mission, noting they need additional funding to staff mission control and keep heliospheric instruments operational, as data transmission requires significant human oversight to manage the spacecraft and deep space network coordination.
Discussed in detail, the New Horizons mission and its capabilities, highlighting that the Roman telescope would be crucial for their current search as it offers 50 times the capability of James Webb for this type of exploration. When asked about the impact of AI on spacecraft design, Alan explained that while AI could help speed up processes and reduce risks today, it was not available during New Horizons’ design in the early 2000s, though the spacecraft remains fully functional after nearly 21 years. Alan also provided details about the Arrokoth flyby, explaining they passed at a distance of a few thousand miles and that Arrokoth measures about 35 kilometers in length, and confirmed that New Horizons continues to collaborate with Johns Hopkins Applied Physics Lab for mission control and spacecraft operations.
Alan discussed the surprising diversity of Kuiper Belt objects, explaining that these dwarf planets exhibit greater diversity in parameters like composition, satellites, and reflectivity than the terrestrial planets. He recommended a mission to Triton as it would provide insights into Pluto while also allowing study of the Neptune system with better instrumentation than Voyager. When asked about the chemical composition, Alan described three main categories: objects with super-volatile ice like molecular nitrogen and carbon monoxide, those with organic molecules, and water ice balls similar to giant planet satellites. Alan also shared his experience flying on Virgin Galactic’s spacecraft in 2023 and discussed how Starship would be a gamechanger for future planetary missions, particularly enabling human colonization of Mars and other missions that weren’t possible before.
The importance of nuclear propulsion systems for space exploration was talked about, explaining that while chemical rockets are necessary for Earth launch, nuclear fission and fusion systems could significantly reduce transit times across the solar system. He highlighted that nuclear systems offer specific impulses 10-100 times higher than chemical rockets, with fusion drives potentially enabling travel to Pluto in under a year. The group discussed specific technical details about nuclear thermal propulsion, with Alan recommending that interested parties consult NASA’s development plans and the Helicity Space website for more information. At the end of the discussion, Alan offered to provide contact information for Stephane Lintner, CEO of Helicity Space, for potential media opportunities.
Bill proposed an idea for the end-of-life operation of the Voyager spacecraft, suggesting that when it can no longer point at Earth, it could be put into a tumble to transmit an intermittent carrier wave signal. Alan explained that while the concept was interesting, the Voyager high-gain antenna’s narrow beam would likely make successful Earth communication intermittent once it loses tracking ability. Alan also discussed his work on fusion propulsion systems for spacecraft and mentioned plans for a potential NASA mission to intercept interstellar comets, which would require rapid response capabilities. The group discussed the temporary naming of Ultima Thule and its eventual formal naming process.
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