Earth Protection from
Mars Sample Return Missions

NASA has plans to conduct a series of sample return missions from Mars within the next 10 years. The ultimate goal for these sample return missions is, to determine if there is or has been, life on Mars. A proposed set of guidelines now exists on how to maintain the scientific integrity of these samples and to ensure that there is no contamination of our environment from these samples. The following table summarizes the proposed sample return contamination control procedures.

Mission Phase	Procedure
1) Pre-Launch	1) Partial Sterilization
2 ) Launch	2) Bioshield
3 ) Sample Handling	3) Seal, Preservation
4) Transit Vehicle	4) Break Surface Contact Chain
5) Earth Return	5)Terrestrial Containment Faculty

The above proposed procedures include:

1) sterilization, by some suitable method, of spacecraft parts that will come in contact with the surface material;

(2) enclosing the spacecraft in a bioshield to prevent recontamination during launch and cruise;

(3) sealing of the sample, its preservation at as close to ambient as possible, and returning it to Earth unsterilized;

(4) breaking the contact chain with the surface by transfer of the sample canister to another vehicle or external sterilization of the return vehicle; and,

(5) return of the sample to an Earth based containment facility where a quarantine protocol could be performed on the sample, if required.

Reference:

DeVincezi, D. L., and H. P. Klein, Planetary Protection Issues for Sample Return Missions,Adv. Space Res., Vol. 9, No. 6, pp. (6)203-(6)206, 1989.