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  • Writer's pictureQuinn Morley

Save Mars Sample Return With In-Situ Radioisotope Sterilization of Samples

Updated: May 30

Springtime at Mars' South Pole. ESA/Mars Express.
Springtime at Mars' South Pole. ESA/Mars Express.

Contamination between planetary bodies is a paramount challenge for sample return missions. For Mars Sample Return (MSR), strict planetary protection rules for containment and "breaking the chain" result in additional mass and increased complexity for sample return systems. Each link in the chain of sample return becomes heavier and more expensive. These factors are at the root of current MSR challenges, including the threat of mission cancellation if budgets continue to balloon.

However, ionizing radiation from small amounts of radioisotope can be used to sterilize Martian samples in-situ, reducing architecture costs, spacecraft mass, and mechanical complexity. A specially-designed, patent-pending sample container which houses around 30 grams of radioisotope provides a Sterilization Assurance Level (SAL) on the order of 10^-21 over the three-year journey home from Mars.

By tackling planetary protection head-on, instead of introducing mechanical layers of protection throughout the architecture, this novel approach has the potential to unlock sustainable -- not simply feasible -- architectures for Mars Sample Return (MSR). Two architectures for returning samples from the surface of Mars are proposed below, both of which are carefully designed around in-situ sample sterilization. Download our white paper via the link below.


In-Situ Radioisotope Sample Sterilization - White Paper
Download PDF • 1.66MB


In-Situ Sterilization Enabling Sustainable Mars Sample Return With a Mini-MAV


The proposed Orbiting Sample container (OS) has a mass of 2.4 kg, enabling a MAV of under 150 kg. Because of the reduced size and mass of this "Mini MAV" (MMAV), the down-mass fits within the envelope of a modified Perseverance-class rover.


In-Situ Sterilization Enabling Mars Sample Lofting via High-Altitude Hybrid Balloons and a Skyhook


A 40-m solar balloon can carry the proposed 2.4 kg OS to an altitude of 30 km, and as high as 60 km if the solar balloon is a hybrid which can achieve photophoretic propulsion. A purpose-built skyhook system can retrieve the OS from the hybrid balloon at 60 km altitude. The “risk” of the skyhook retrieval method enables the use of an InSight-class lander, which flew for $829 million.


Save Mars Sample Return!

Planet Enterprises, in collaboration with G21 Nucleonics, University of Pennsylvania, Astralytical, and Orbital Arc, hope that this unique approach to Mars Sample Return can:

  1. Provide a sustainable architecture for MSR, or

  2. Help contribute to the return of MSR to a programmatically feasible footing in some way, or

  3. Inspire other innovative MSR solutions or collaborations, thereby contributing at least in a secondary fashion to the ultimate MSR solution.

For these reasons, we are releasing this white paper version of our two Rapid Mission Design Studies for Mars Sample Return (RAS MSR ‘24) proposals to the public. Our enthusiasm for the contributions to science which returned Mars samples will offer humankind is genuine, and we believe this inspirational planetary science program can become one of the defining events of the 21st century—if it loses a little weight, while still keeping both planets safe.

If you would like to collaborate with us or license this technology, please reach out to us at For all other inquiries, please use Thank you!

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