IMPLICATIONS OF MICRO-ORGANISMS FOUND ON ISS AND MARS ROVER
The discovery that there are micro-organisms living and growing on the ISS and on and near the Mars Curiosity Rover brings to light questions of great importance concerning both the issue of extraterrestrial life and the issue of human intentions for exploration beyond earth.
In exploring some of the issues concerning the latter — explorations beyond earth — questions brought up by this need to be dealt with if we are to explore the cosmos. One issue is the source of these extremophiles. It is unknown for a certainty what their sources are. If their sole source is earth, then perhaps the answer lies in finding effective ways to completely sterilize spacecraft. If some of them are found to be sourced in space, then the problems could possibly increase exponentially.
As reported online by the publication: “ cosmology.com” to be found at: http://cosmology.com/FungiContaminateMarsRovers.html the extent and speed of the damage caused by these micro-organisms to the Curiosity Rover is worrying and the finding that there are organisms growing on and actually causing damage to the titanium glass of the ISS must certainly give pause to those considering the integrity of materials of which space exploration vehicles are to be constructed. Questions of how long our machines can last, even in deep space, must be tackled. Space has so long been considered quite sterile that I doubt that much time and effort has been given to these considerations. Most of the dangers considered so far have been more on the order of radiation, micrometeorites and the very long-term reliability of equipment.
The deep cold of deep space may be one answer to the dilemma. All chemical reactions including biological ones are vastly slowed or even brought to a halt at temperatures approaching absolute zero. That of course may solve some problems. However, if there are devices that must operate with any efficiency in such vessels then it would seem that there would likely need to be some components needing to maintain higher temperatures that might allow these organisms to grow. Given the range of substrates that these extremophiles can grow on and damage, substances such as aluminum, steel, plastics, titanium glass, etc., these organisms may prove to be extremely difficult to defend against. Vessels that carry living beings of course need be maintained at more hospitable temperatures so the deep cold of space would not be so helpful.
Part of the answer might be found in oxygen, one of the most reactive chemicals. These life forms are of necessity anaerobic. Many, though not all, anaerobic organisms are poisoned and even killed by oxygen. The spore forms of some of these are impervious to oxygen, though. One clue to the puzzle of this issue may be that the traffic back and forth to the ISS and to earth does not seem to have released upon us any highly destructive micro-organisms so far. Perhaps coatings could be devised that release reactive oxygen when attacked. This might possibly be helpful but is unlikely to be helpful in all cases. Chlorine, used in the same way is another possibility and there are likely other chemicals, such as reactive oxygen and nitrogen species, that might be helpful. Objects that we send into space will probably be there a very long time so these organisms could have a very long time to do their damage.
Other possibilities might be to use exotic forms of more familiar materials. “Metal glass,” metals that through forming procedures or when alloyed with precise amounts of other metals so that their molecular structure is amorphous rather than crystalline are quite resistant to corrosion, though the reports of the organisms growing on and damaging titanium glass, which is an amorphous material, is worrisome. Carbon being the basis of organic life makes it’s use questionable, though perhaps some of it’s forms may be somewhat impervious to damage. Diamond is a possibility and recently discovered processes to create diamond by atomic deposition might eventually make this feasible. Then there is graphene. Graphene seems to be the strongest material in existence and as new and more efficient methods of producing it are developed we will probably see it become more practical to make and use. Early research into graphene coatings are showing orders of magnitude improvements in corrosion resistance for many metals. it will be interesting to see how far this goes.
A number of publications have stated that the microbes allegedly seen to be living on and near the Mars Curiosity Rover are likely the result of contamination from earth carried on the rover.
I have read some information about the impossibility of sterilizing the large devices we send to otherworldly destinations as well. Although some seem ready to proclaim that all of these microbes are from earth, the only thing that seems clear to me is that we don’t know for a certainty the source of nor what is going on with these particular life forms. Yes, we have undoubtedly transported microbiota both to the ISS and Mars. However, in the case of the organisms on Mars there are some rather exceptional considerations. If one looks at the deterioration of parts of the Rover, these life forms seem not only to be eating or at least corroding parts of the machinery but doing this at an exceptionally high rate of speed.
There are microbes on earth that will degrade metal surfaces. However, I cannot recall ever having come across reports of microbes that caused such rapid deterioration of similar substances in such dry and exposed circumstances on earth. It is at this time impossible to know why this is occurring. Perhaps the dry, cold, thin atmosphere of Mars has somehow invigorated earthly organisms to new heights of achievement. However, this seems somewhat unlikely as life on planet Earth would seem to have afforded such organisms little evolutionary opportunity to develop such skills. It seems possible that it might (Please note my qualifiers.) be rather more probable for organisms that have evolved under martian conditions to flourish and act upon their substrates with such vigor. However, all of these conjectures, are at this time nothing more than speculation.
The knowledge that what we have sent beyond earth is biologically contaminated gives only a correlation and therefore hypothetical evidence and cannot at this time be elevated to the level of factual evidence of origin of all the microbes and certainly not to the level of proof. For that we must await the results of further studies. For the present these phenomena must serve as a cautionary note to those who continue to send items off planet and to those who are planning to establish colonies on moons and planets beyond earth.