Radiation poses a major challenge for long-duration space missions, including future trips to Mars planned by NASA and SpaceX. Traditional shielding, while effective, is heavy and expensive to launch from Earth. A recent study explores the idea of using Near-Earth Objects (NEOs) as natural radiation shields to protect astronauts during interplanetary travel.
Asteroids as natural spacecraft shields
Researchers Victor Reshetnyk and a student at Taras Shevchenko National University in Kyiv analyzed data from NASA’s Horizons service. They studied the orbits of over 35,000 NEOs to find asteroids that naturally travel along routes between Earth, Venus, and Mars.
The team identified 525 candidates capable of fast transfers under 180 days. To make the concept realistic, they narrowed the list to asteroids with approach speeds manageable for a spacecraft to catch without excessive fuel consumption. This reduced the options to 120 viable candidates.
Although promising, these asteroids are small. The largest identified candidate is just 0.37 kilometers in diameter—large enough to provide shielding for a spacecraft but far from spacious.
Some asteroids exhibited unique trajectories:
- 11 asteroids could make multiple transfers, such as Earth to Venus and back.
- 2 asteroids could achieve a “double transfer,” like Earth to Venus to Mars, in under a year.
No asteroids with continuous looping orbits (like an “Aldrin Cycler”) were found, though undiscovered candidates may exist.
The role of future missions
NASA’s NEO Survey, launching in 2028, aims to catalog 90% of NEOs larger than 140 meters. This mission could significantly expand the list of viable asteroids, increasing opportunities for asteroid-based radiation shields.
While turning an asteroid into a functional shield for crewed Mars missions remains decades away, this research offers a promising step forward. By identifying natural space resources, future missions could become safer, cheaper, and more efficient.
Source: phys.org.
