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Finding safe impact zones to deflect hazardous asteroids

by Erica Marchand

Paris, France (SPX) Sep 11, 2025

Selecting the point of impact for a kinetic deflection mission is not trivial, according to research unveiled at the EPSC-DPS2025 Joint Meeting in Helsinki. Striking the wrong location could nudge a hazardous asteroid through a gravitational keyhole and set up a future Earth encounter.

“Even if we intentionally push an asteroid away from Earth with a space mission, we must make sure it doesn’t drift into one of these keyholes afterwards. Otherwise, we’d be facing the same impact threat again down the line,” said Rahil Makadia, a NASA Space Technology Graduate Research Opportunity Fellow at the University of Illinois at Urbana-Champaign.

NASA proved kinetic impact can alter an asteroid’s path when DART hit Dimorphos, the small moon of Didymos, in September 2022. DART acted as a high-speed projectile to change Dimorphos’s orbit, demonstrating deflection. ESA’s Hera mission will arrive at Didymos and Dimorphos in December 2026 to characterize the aftermath.

Because the Didymos system is too massive to be redirected toward Earth, DART’s exact impact point mattered less. For other Sun-orbiting objects that pose risk, even small orbital tweaks could route them through a keyhole, a narrow region where a planet’s gravity reshapes a flyby into a later collision course.

“If an asteroid passed through one of these keyholes, its motion through the Solar System would steer it onto a path that causes it to hit Earth in the future,” said Makadia. Avoiding those zones requires mapping how surface strike locations translate into post-impact trajectories and their associated probabilities.

Makadia’s team has devised a method to compute probability maps across an asteroid’s surface, guided by DART results but tailored to each target. Inputs include the body’s shape, topography, rotation and mass. Ideally a rendezvous mission provides these data, but timelines may preclude that for newly found threats.

“Fortunately, this entire analysis, at least at a preliminary level, is possible using ground-based observations alone, although a rendezvous mission is preferred,” said Makadia. By propagating paths from many candidate impact points and flagging those that intersect keyholes, planners can identify safer strike zones.

“With these probability maps, we can push asteroids away while preventing them from returning on an impact trajectory, protecting the Earth in the long run,” said Makadia. The approach offers a practical framework to select impact sites that deflect danger without unintentionally scheduling a future impact.

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Chinese astronauts expand science research on orbiting space station

by Riko Seibo

Tokyo, Japan (SPX) Sep 11, 2025

Shenzhou 20 astronauts – Chen Dong, Chen Zhongrui and Wang Jie – are pushing forward with wide-ranging scientific experiments and technology tests aboard China’s space station, advancing knowledge across multiple research domains.

In space medicine, the crew used electroencephalogram equipment for experiments including visual field studies, executive-function training and exploratory utilization projects. They also employed eye-tracking devices and specialized software to investigate microgravity’s impact on relational cognition and on how astronauts develop trust in AI assistants during extended missions.

The astronauts underwent vascular ultrasound scans, gathering data on organ morphology, blood flow dynamics and functional measures across different mission durations. These findings are expected to improve understanding of how the human circulatory system adapts to long-term weightlessness.

In human-factors technology studies, the crew analyzed operational forces such as push-pull and rotational movements in microgravity, comparing them to terrestrial conditions. This work helps clarify the mechanisms behind variations in astronaut performance over time in orbit.

They also installed and tested a universal biological cultivation module inside the station’s ecological experiment cabinet, creating new opportunities for life science research in space.

Alongside these experiments, the crew continues to maintain station systems and follow health protection protocols to support safe, sustained operations.

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Radiation may explain organic molecules in Enceladus plumes

by Erica Marchand

Paris, France (SPX) Sep 11, 2025

Organic molecules discovered in the geyser-like plumes erupting from Saturn’s moon Enceladus may form when surface ices are exposed to radiation, rather than originating in its hidden subsurface ocean, according to new research presented at the EPSC-DPS2025 Joint Meeting in Helsinki.

Dr Grace Richards of the Istituto Nazionale di Astrofisica e Planetologia Spaziale (INAF) explained that while Cassini’s detection of complex organics in Enceladus’s plumes remains compelling for habitability studies, laboratory simulations suggest that Saturn’s radiation environment could generate similar molecules directly on the moon’s icy surface.

Discovered in 2005, the plumes rise from south polar fractures known as tiger stripes, powered by tidal heating from Saturn’s gravitational pull. Cassini revealed salts and varied organic molecules in the ejected material, raising hopes that the ocean beneath Enceladus could host prebiotic chemistry and potentially life.

Richards’s team, supported by Europlanet, replicated Enceladus-like ices at -200C containing water, carbon dioxide, methane and ammonia at Hungary’s HUN-REN Institute for Nuclear Research. Bombarding the ice with energetic ions produced compounds including carbon monoxide, cyanate, ammonium and amino acid precursors. Some of these chemicals match those already observed in both Enceladus’s surface and its plumes.

“Molecules considered prebiotic could plausibly form in situ through radiation processing, rather than necessarily originating from the subsurface ocean,” Richards said. “Although this doesn’t rule out the possibility that Enceladus’s ocean may be habitable, it does mean we need to be cautious in making that assumption just because of the composition of the plumes.”

Differentiating between ocean-derived and radiation-formed molecules will require data from future missions. One concept is a dedicated Enceladus mission under consideration in ESA’s Voyage 2050 program, which would extend exploration planning into the middle of the century.

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