ESA’s Hera mission, launched in October 2024, is now en route to the Didymos binary asteroid system to complete the first full-scale test of planetary defense begun by NASA’s DART impact in 2022. By arriving in 2026, Hera will transform a headline-grabbing collision into quantified science, measuring how the kinetic strike altered Dimorphos and its orbit. The mission aims to turn a successful demonstration into an engineering blueprint for future asteroid deflection strategies. It is a tightly coordinated international effort designed to answer how, and how well, humanity can nudge a hazardous object off course.
Remove buoyancy, sedimentation, and natural convection, and physics—and biology—behave in surprising ways. That is the premise behind zero-gravity research on platforms such as the International Space Station (ISS), drop towers, parabolic flights, and suborbital rockets. Over the past two decades, this weightless laboratory has enabled experiments that are hard or impossible on Earth, from quantum gases that linger longer to flames that burn without a visible glow. The results are reshaping textbook assumptions, informing spacecraft engineering, and seeding practical advances in medicine and manufacturing. As new facilities come online and commercial stations take shape, microgravity is evolving from a novelty into a precision tool for discovery.
Humanity has not yet launched a spacecraft explicitly aimed at another star, but the first attempts are underway in the form of precursor missions, engineering studies, and enabling technologies. The Pioneers, Voyagers, and New Horizons are slipping into interstellar space, while decades of design work—from fusion rockets to laser-pushed sails—has turned science fiction into engineering roadmaps. In the 21st century, solar-sail demonstrations, chip-scale spacecraft, optical communications, and directed-energy research are converging on concepts like Breakthrough Starshot, which envisions gram-scale probes racing to Alpha Centauri. Interstellar “precursor” mission studies seek to push far beyond the heliosphere as a stepping stone. These are the groundwork phases of a project measured in decades, not years, but they mark humanity’s first concrete moves to send emissaries to other star systems.
Asteroid impacts and solar storms are low-probability but high-consequence events, and Earth is taking them seriously. A global network of telescopes, spacecraft, and emergency planners now works in concert to spot hazardous objects, test ways to nudge them off course, and prepare for worst-case scenarios. Recent missions have demonstrated that deflection is possible, while new surveys promise to find threats earlier. At the same time, space-weather forecasters are improving warnings that protect satellites, power grids, and aviation. Planetary defense has moved from science fiction into practical policy.
