Public Perceptions, Priorities, and Solar System Exploration
PART 2: SURVIVAL ON THE MOON?
of the retrieval of the Apollo 12 crew at splashdown show that they were not wearing their protective “biological isolation garments.” Once the astronauts were moved from their capsule to an aircraft carrier, they donned their pro- tective garments and entered an isolation unit aboard the carrier. The sample pack containing the Surveyor camera parts was retrieved along with other equipment inside the capsule and returned to the MSC. The sample pack was taken to and quarantined at the Lunar Receiving Laboratory, where “it was placed inside of two Teflon bags and sealed for storage at room temperature.”7 Available NASA records do not clearly indicate who may have handled the camera sample pack in the trip from inside the capsule after splashdown to the carrier and then to the LRL.8
survived on the lunar surface for two and a half years, and, once returned to Earth, revived, and reproduced. NASA had not anticipated the return of Surveyor components to Earth, so it had not conducted any microbial analy- sis of the Surveyor camera’s interior before launch. “Decontamination mea- sures taken before the Surveyor launch did not eliminate the possibility that the spacecraft carried organisms to the moon,” they asserted.12 They noted that conditions during prelaunch vacuum testing and later on the lunar sur- face could have freeze-dried any biological material on the spacecraft and could have played a role in enabling S. mitis to survive on the Moon.
Mitchell and Ellis described the conduct of the Surveyor III camera anal- ysis in great detail. A brief summary of their report follows, starting with cleanroom procedures:
The…camera was placed in a laminar-outflow hood equipped with high- efficiency particulate air filters…in the LRL astronaut debriefing room, which has an air-conditioning system separate from the system used by the rest of the LRL. Every surface of the…hood which would be exposed to the camera was thoroughly washed twice with isopropyl alcohol prior to the camera being placed in the hood…. Only those personnel directly respon- sible for disassembling and sampling the TV cameras were permitted in the room. They were clothed in…surgical caps, face masks, and sterile gloves.13 Samples taken from the Surveyor camera parts were applied to three different types of growth media for aerobic, anaerobic, and mycological analysis. “The protocol established for the aerobic and anaerobic analyses…
contained a system of redundancy and cross-checks designed to identify sus- pected laboratory contamination.… Obvious cases of laboratory contamina- tion could easily be identified and reported as such,” they reported.14 Swabs from only one sampled surface—a 1-cubic-millimeter piece of foam inside the camera—yielded visible microbial growth.
“Every step in the retrieval of the Surveyor III TV camera was analyzed for possible contamination sources, including camera contact by the astro- nauts; ingassing in the lunar module and command module during the mis- sion or at ‘splashdown’; and handling during quarantine, disassembly, and analysis at the LRL,” they said. Mitchell and Ellis dismissed the possibility of contamination by astronauts during retrieval from the Moon as “no viable
12. F. J. Mitchell and W. L. Ellis, “Surveyor III: Bacterium Isolated from Lunar-Retrieved TV Camera,” p. 2721.
13. Ibid., pp. 2723–2724.
14. Ibid., pp. 2725–2726.
terrestrial microorganism has ever been detected in the [lunar] samples col- lected by the astronauts.” They also surmised that the camera’s shroud “may have provided a formidable barrier to ingassing carrying fine particles, per- haps even the size of a bacterium…. Extreme precautions were taken at all times during the analysis to prevent any handling errors which might have caused contamination.”15
“The available data indicates,” they concluded, “that Streptococcus mitis was isolated from the foam sample and suggest that the bacterium was deposited in the Surveyor III TV camera before spacecraft launch.”16
At the very same meeting, M. D. Knittel, M. S. Favero, and R. H. Green presented a paper in which they reported on the results of microbial sam- pling of returned Surveyor III electrical cabling.17 Knittel and Green were both with the Jet Propulsion Laboratory, where Surveyor spacecraft were
15. Ibid., pp. 2728–2729.
16. Ibid., p. 2732.
17. M. D. Knittel, M. S. Favero, and R. H. Green, “Microbial Sampling of Returned Surveyor III Electrical Cabling,” Proceedings of the Second Lunar Science Conference, vol. 3 (Cambridge, MA: MIT Press, 1971), pp. 2715–2719.
Photo taken in January 1970 of the Surveyor III camera being examined. (NASA: P-10709B)
developed.18 Favero was with the Phoenix Field Station of the U.S. Public Health Department. They reported on the results of an experiment they con- ducted to determine whether terrestrial microbial life, if any had been pres- ent on Surveyor III upon launch, could have survived 31 months of exposure to lunar surface conditions. Their findings raised some questions about Mitchell and Ellis’s report.
Knittel, Favero, and Green chose to examine a piece of electrical wire bun- dling running from the Surveyor camera to another part of the spacecraft, because earlier studies had shown that “a high level of microbial contamina- tion [was] associated with wiring bundles.”19 “If, during the actual sampling of the wires,” they observed, “a contaminant were accidentally introduced, it would be impossible to separate it from a lunar survivor.” Thus “it was necessary,” they said, “to perform several simulated assays with a piece of sterile wiring bundle before the lunar sample was assayed. During these simulated assays, all of the procedures that were to be applied in sampling of the Surveyor III cable were used to determine if the sampling could be done without contamination. These procedures increased the confidence that the Surveyor III cable could be examined without contamination.”20
“Prior to opening the Sealed Environmental Sampling Container contain- ing the Surveyor III cable and other parts,” they reported, technicians dis- covered that it had leaked. “When the [container] was opened, it was found to contain a high concentration of oxygen… There was concern whether air- borne bacterial contamination of the exterior wraps would penetrate to the interior of the wiring bundle.” Their work in the lab showed that “if airborne bacteria did pass into the [container] through the leak, the wiring bundle wraps would protect the wires beneath it from contamination.”21
Their results showed “that no viable microorganisms were recovered from that portion of Surveyor III cable that was sampled…. The prelaunch ther- mal and vacuum testing of the Surveyor III spacecraft could have accounted for a major reduction in the bacterial contamination,” they noted. Knittel, Favero, and Green concluded “that no microorganisms survived on the wir- ing bundle during its lunar exposure. That is not to say that a microorgan- ism cannot survive exposure to the lunar environment, but only that none
18. In their paper (p. 2733), Mitchell and Ellis acknowledged Knittel “for supervising the selec- tion of sampling sites and assisting in the [Surveyor] sampling” and Green for “technical and administrative assistance.”
19. Knittel et al., p. 2715.
20. Ibid., p. 2716.
21. Ibid., pp. 2716–2717.
were found on the returned piece.”22 The implication was that if no viable microbes were found on these protected wiring samples, then it would not be likely that any viable microbes would be found on other hardware samples taken from Surveyor III.
NASA subsequently published the findings of both Mitchell and Ellis and Knittel et al., as they were reported at the 1971 Lunar Science Conference in a 1972 report, “Analysis of Surveyor 3 Material and Photographs Returned by Apollo 12.”23
Did Mitchell and Ellis prove that S. mitis could survive on the Moon and come back to life on Earth? Did Knittel, Favero, and Green’s findings raise serious doubts about Mitchell and Ellis’s claims? Subsequent developments further complicated the story of S. mitis on the Moon.