Nuclear Power in Space, Planetary Defense Insights, and an Aurora Alert for Northern Skies

Astronomy Daily — S05E135 — Wednesday, July 8, 2026 1. World's First Commercial Nuclear-Powered Satellite Reaches Orbit SpaceX's Transporter-17 rideshare mission carried City Labs' BOHR CubeSat to orbit on July 7, the first commercially built satellite to fly a nuclear-powered payload — a tritium betavoltaic cell that generates electricity continuously, day or night, regardless of sunlight. Key points •      Launched July 7, 2026 at 3:12am EDT from Vandenberg Space Force Base aboard a Falcon 9, part of the 81-payload Transporter-17 rideshare mission. •      BOHR (Betavoltaic Orbital High-Reliability) CubeSat built by City Labs, a Miami/Florida-based company. •      Uses a 'NanoTritium' betavoltaic device — converts beta particles from the radioactive decay of tritium directly into electricity via a semiconductor. •      Power output is tiny (micro-to-milliwatt range) but continuous — unaffected by eclipse periods or solar panel orientation. •      Tritium's 12.3-year half-life means the power source stays effective for two decades before decaying to harmless helium-3. •      FAA authorised the launch after finding public radiation exposure would stay below one millirem under conservative assumptions. 2. New Zealand's Fuel-Free Thruster Passes First Orbital Test Auckland-based Zenno Astronautics has successfully tested its 'Supertorquer' — an attitude-control thruster that uses superconducting magnets to push against Earth's own magnetic field, generating thrust with no propellant at all. Key points •      Zenno Astronautics is a spin-off from the University of Auckland, New Zealand. •      The system, called 'Supertorquer', completed its first in-orbit test in early July 2026. •      Superconducting magnets, powered by solar panels, interact with Earth's magnetic field to generate torque and maintain a satellite's orientation — no propellant is consumed. •      Until recently this kind of superconducting hardware was too large and complex to fit aboard a small satellite; miniaturisation has now made it practical. •      Because it needs no fuel, the technology could in principle keep a satellite maneuvering indefinitely, as long as it has sunlight for power. •      Zenno co-founder/company messaging: 'We are essentially looking to remove all reliance on Earth's resources so that we can build a sustainable industry in space.' 3. Tianwen-2 Arrives at Quasi-Moon Kamo'oalewa — And Upends the 'Piece of the Moon' Theory China's Tianwen-2 sample-return spacecraft has arrived at near-Earth asteroid Kamo'oalewa after a 400-day, 1-billion-kilometre journey, beaming back the first close-up image — just as new JWST data throws serious doubt on the leading theory of where this strange little world came from. Key points •      Tianwen-2 launched May 29, 2025, and reached Kamo'oalewa on July 6, 2026, arriving at a station-keeping distance of about 20 km. •      China National Space Administration (CNSA) publicly announced the arrival July 6, releasing the first close-up image via Xinhua. •      Kamo'oalewa (asteroid 2016 HO3) is one of only seven known 'quasi-satellites' of Earth — it orbits the Sun but stays in a stable dance alongside our planet, and has done so for roughly 100 years, with about 300 more to go. •      The image reveals a small, asymmetrical rock roughly 20-30 metres across. •      Long-standing hypothesis (since 2021): Kamo'oalewa is a fragment blasted off the Moon's far side by the impact that created the Giordano Bruno crater, 1-10 million years ago — based on its reflectance spectrum resembling space-weathered lunar soil. •      New twist: a July 1 JWST preprint (Sharkey et al.) models Kamo'oalewa's albedo (reflectivity) at around 0.59 — far higher than the Moon's ~0.12 — which is incompatible with a lunar origin and points instead toward a rare E-type silicate asteroid. 4. Jeremy Hansen Steps Back From Active Astronaut Duty Jeremy Hansen, the Canadian Space...