Will Subsurface Samples from a Comet Rewrite Solar System History?
Pioneering Japan’s Next-Generation Comet Sample-Return Mission
Japan’s space agency, JAXA, revolutionized asteroid science with its Hayabusa and Hayabusa2 missions—returning pristine samples from Near‑Earth Asteroids Itokawa (2005) and Ryugu (2018). Building on those triumphs, an international team led by Naoya Sakatani (JAXA/ISAS) has proposed the Next Generation Small‑Body Sample Return (NGSR) mission, targeting a comet in the 2030s to unlock the Solar System’s most primordial secrets.
Strategic-Scale Mission Concept for Comet Sample Return
Rather than merely visiting an asteroid, NGSR aims to rendezvous with a Jupiter‑family comet—specifically 289P/Blanpain, which swept past Earth at 13.6 million km in 2020—and bring back subsurface material that has never felt the Sun’s heat or space weathering. Why subsurface? Because these samples remain unaltered since the Solar System’s birth 4.6 billion years ago, offering a time capsule of nebular chemistry.
Scientific Goals: Probing Primordial Organic and Mineral Origins
Unraveling Presolar Grain Histories
Asteroidal samples show that presolar grains suffered parent‑body metamorphism. Could cometary samples preserve these grains in their original form?
Tracing the Origins of Life’s Building Blocks
Asteroid returns revealed amino acids and complex organics. Will comet samples answer whether life’s precursors truly came from the outer Solar System?
Testing Nebular Hypothesis Models
How did dust grains overcome gas drag and coalesce into kilometer‑scale planetesimals? Direct measurement of unprocessed comet interiors could provide the first empirical evidence.
Mission Architecture: DSOTV, Lander, and Cutting‑Edge Instruments
Deep Space Orbital Transfer Vehicle (DSOTV)
– Carries the sample return capsule back to Earth via an ultra‑high‑speed reentry.
Surface Lander with Small Carry‑on Impactor (SCI)
– Proven on Hayabusa2, the SCI will excavate buried ice and dust.
Advanced Sensor Suite
– Optical Navigation Camera for precise topography.
– Bistatic Radar & Seismometers to probe internal structure.
– Thermal Infrared Camera to map physical properties.
– LIDAR & Gravity Measurements to chart mass distribution.
Timeline: From 2034 Launch Window to 2048 Earth Return
Assuming a 2034 departure, NGSR will span 14 years, including cruise, comet operations, and Earth return. Can JAXA leverage this extended timeline to refine our models of Solar System formation—and maybe even catch the first whispers of life’s extraterrestrial origins?
Questions to Propel Future Research
What presolar grains might remain intact in cometary samples, and what can they tell us about the interstellar medium?
How will organic complexity in comets compare to that in asteroids like Ryugu and Bennu?
Can seismology on a comet reveal clues about early planetesimal porosity and strength?
Might comets hold a greater reservoir of water‑rich minerals critical for understanding Earth’s oceans?
By returning pristine cometary material, NGSR promises to fill critical gaps in our understanding of how the Solar System—and potentially life itself—came to be. As we look ahead to the 2030s, one question looms largest: What cosmic secrets lie buried beneath a comet’s frozen surface, waiting for us to uncover them?
Source: Will Subsurface Samples from a Comet Rewrite Solar System History?