I wonder if this article is confusing two different types of clean room.
I can understand why a lander like Phoenix has to be biologically clean, needing bio-isolation and alcohol-swabbed surfaces, but why is there this requirement for the Herschel space telescope? It stays in space. Surely the telescope would just require protection from dust, etc. during assembly in an environment similar to a chip fab? I'm not too surprised that bacteria could find their way into such an environment.
I worked IT for JPL's Cleanroom Group a few years ago. Biological contaminants are only one factor. 95-99% of the cleanrooms they have are not much cleaner than something like a typical elementary classroom with a well kept air filtration system (not great). These are Class 100K rooms [1]. Less than 100K particles of 0.1 um size or bigger per m^3 of air (dust, hair, skin, anything really). Offenders of contaminating the rooms some brought in unapproved or contaminated materials, like non-cleanroom notepads or gaseous/non-cleanroom markers/pens, cardboard. The reason why the rooms were not operated cleaner is because of their size. Some were large like 40m by 40m by 40m (the main Spacecraft Assembly Facility where the Herschel instrument saw final assembly), others housed special capabilities like the 25-foot Space Simulator [2], shakers and bakers (rotation/vibration test pedestals, and space vacuum hot/cold chambers), or isolation pads (pedestals mounted on ultra heavy 40'x40'x40' blocks of concrete to reduce vibration for optics instrument testing). It was also common practice to certify a room at one level, and operate it like it was the next higher level with minimal cost and maximal benefit. Things like additional air exchanges, daily or twice daily cleanings (instead of weekly), extra HEPA filters, stricter ESD operations, stricter temperature and humidity control (ESD & Planetary Protection reasons). This was often more than sufficient to appease the Principal Investigators, Instrument Designers, and Planetary Protection.
Many rooms were Class 10K capable. A few were Class 1K or Class 100 capable. But those were very small rooms, sometimes even 10'x10'x10' tents setup in a one level less capable room. Only two rooms operated were even capable of operating at Class 100, IIRC, and only did so when necessary. There were apart of chip fabrication building.
To answer your question, Herschel has its base requirements similar to anything we send off into space, and then it had it optics instruments requirements. Projects have been ruined when instruments do not work or do not work as well as designed because of dust, ESD, or a hair particle. It's really hard/expensive to wipe your lens with a microfiber cloth in space; JPL once did a study to determine the cost/feasibility. It dwarfed the original project.
Scientists go to all this trouble for the purpose of “planetary protection”—which usually means protecting other planets from contamination by microbes originating on Earth. Most spacefaring countries have agreed to follow guidelines from the International Council for Science’s Committee on Space Research to reduce the chances of their vehicles carrying Earth organisms to other planets. The clean room procedures also safeguard against scientists mistaking Earthly microbes as extraterrestrial in origin if they are discovered on another planet, having caught a ride with a man-made spacecraft. “The whole idea of collecting information about what kind of bugs we have in the spacecraft assembly facility is to have baseline information so that in the future, if you find it on Mars, you have some grounds to rule out the possibility that it came from Mars,” Vaishampayan says.
Being able to make the distinction between panspermia induced by human activity, and panspermia that occurred through some other mechanism is important. The possibility that life jumped the gap on meteorite strike debris does not make protecting against contamination any less important.
Actually, I would say that it makes it more important. If there was no possibility for non-human related panspermia, then if we found an organism on Mars that appears closely related to an earth organism, then we could write it off as contamination and ignore it. However since non-human related panspermia could conceivably happen, it would be more difficult to pin such a discovery on contamination.
Citation please (sounds interesting, but yeah), and does it get exchanged at the speed that this stuff does, or does it take thousands^x years to arrive?
Not that I disagree. Just wondering if there are a few orders of magnitude that need to be considered.
Looking back for the specific citation, I can't find it. Looking naively to find the source, it seems like it was an estimate (I mean, we know there are meteorites, but the actual frequency and when they landed, and the total amount isn't known exactly).
http://arxiv.org/pdf/1205.1059v1.pdf
(ignore the part about lithopanspermia. I'm just discussing the facts of the matter, not the crazy speculation part).
OK. Turns out I was using the wrong search term. It's "meteorite flux",
and here are several sources. Unfortunately, Google obscured the PDF link, so do:
[ mars earth meteorite flux ]
In particular,
"Assessment of Planetary Protection Requirements for Mars Sample Return Missions" has data.
1) agreed. there's solid evidence that Mars sends junk to us - not sure about the other way around.
2) does that matter, since they're in orbit, thus zero/microgravity? You still need energy to leave an orbit, whether up or down, I don't see how it makes a difference. There's no friction to speak of to make "down" a direction that things are predisposed to move in. Over ridiculous time scales sure, but ridiculous time scales are nothing like human time scales, so we still have many orders of magnitude difference if we fling stuff at Mars intentionally.
orbit. gravity is canceled out by orbital velocity, as far as distance-from-sun is concerned. it costs Mars nothing to stay in orbit, and to go down to a -100m/s orbit or up to a +100m/s orbit costs the same amount of energy: (mass of mars) * (100m/s velocity change)
if Mars and the Earth were not orbiting, I would completely agree. drop something from Mars and it'll land on Earth, and the reverse is not true. but they're not - drop something on Mars and it's just in Mars' orbit.
Delta-v requirements for transfers in space are generally symmetrical. It takes the same amount of delta-v to go from Earth's orbit to Mars's orbit, for example, regardless of direction.
The one thing that changes this equation is aerobraking (or, when dealing with stuff whose structural integrity isn't important, lithobraking). Because drag works in one direction, that means that you can take advantage of it when arriving but not departing. For that reason, for example, it takes more delta-v to reach a transfer orbit to Mars from Earth than it takes to reach Earth from a transfer orbit to Mars. Technically that's not true, but when arriving at Earth, a great deal of delta-v can be provided by the atmosphere or the ground.
It's true tat it's been a long time since I played with this stuff, I work out for a circular orbit
Total energy of an orbit is -G mp mS /(2 r)
mp = mass of planet
mS = mass of sun
r = distance of planet from sun
Even though this is a circular orbit, the basic result should be the same: the greater the distance from the sun the more energy the planet has, per unit mass.
I think I understand your basic point, however, which is that whether we speed it up or slow it down we have to do something to the mass, and how much we do depends only on difference of the orbit radii.
But note that adding 100 m/s or subtracting 100 m/s gives two different differences in r.
About #2, it may be the other way round, anything escaping Earth is easily pulled in towards Mars' orbit by the Sun's gravitational pull. The other way round, it requires more energy to escape.
BTW, I found the source of this quote- it's from Craig Venter (he cites it as a reason for sending his DNA sequencer to Mars). I can't find anything supporting his statement, however.
It's a best effort approach to minimize the risk of "contaminating" planets with Earth life. It applies to any spacecraft in interplanetary space, not just landers, because it's impossible to predict where an object that ends up in heliocentric orbit will end up, it could end up hitting another asteroid, planet, or moon.
Presumably it did not spring into existence fully-formed in a clean room in the last hundred years. So, it must be able to live in other conditions but at population levels that are virtually undetectable.
That's the mind-blowing thing for me about this article. The idea is that it can't compete with other organisms out in the wild. Out in the wild, other organisms reproduce too quickly, are too aggressive, devour these bacteria, etc. But these bacteria have something that allows them to survive in a clean room's extreme environment, something that kills off other more competitive organisms. This is the very definition of niche.
I have a bunch of questions born of my ignorance of microbiology:
Is it possible this organism evolved in the last few decades, with the advent of clean rooms? Or is it more likely that a few of these are around all the time, and only multiply extensively in clean rooms? Also, what do they eat or use for energy to reproduce in such environments? And if they don't really eat, how do they not die on a long space journey?
It is possible for it to have evolved in the last few decades, but really unlikely. The stated figure of less than 5% DNA commonality implies a really extensive divergence. Given the low energy environment it grows it, the bacteria likely reproduces at a very slow rate, making the divergence over the last few decades very unlikely.
That said, its probable that the strains discovered are probably some slight "modification" from the "wildtype" bacteria.
As for what they eat in a clean room, there are a couple options. A) They might be driven mostly by alcohol metabolism and feeding off residual alcohol from the containimation. Or might likely B) they're feeding off the skin flakes coming off the "unshielded" areas of the workers, and that they are just very very slow.
The stated figure of less than 5% DNA commonality implies a really extensive divergence.
Your reasoning is correct, but in case you'd like to edit, I'll point out that the article wrote, "The scientists determined that T. phoenicis shares less than 95 percent of its genetic sequence with its closest bacterial relative." The figures "less than 95 percent" and "less than 5%" imply very different degrees of similarity.
Very niche lifeforms by definition are hard to cultivate in a lab and therefore go undocumented and there are loads of them, more than we even suspect probably.
It's likely a new kind of bacteria, because of the genetic difference. But that doesn't mean it hasn't made any additional adaptions for living in clean rooms specifically. Maybe it started out as a bacteria that could survive in an environment like that but has become even better at it since.
Though the hostile environment of a clean room would keep population size relatively low and keep them from reproducing too often, compared to bacteria in normal conditions. So their evolution would be slower.
"Life form" subtilely connotes alien life, doesn't it? Especially when you put it in a sentence with NASA and Spacecraft.
When they discover actual life on Mars and Europa, it's probably going to have a lot less impact due to the lack of self restraint in using desensitizing wording like this among journalists (Scientific American??)
It's only 96% similar to other bacteria we know of. Which is greater than the difference of most mammals to each other. But still pretty similar and not entirely radical in its genetic makeup (in the grand scheme of things).
I can understand why a lander like Phoenix has to be biologically clean, needing bio-isolation and alcohol-swabbed surfaces, but why is there this requirement for the Herschel space telescope? It stays in space. Surely the telescope would just require protection from dust, etc. during assembly in an environment similar to a chip fab? I'm not too surprised that bacteria could find their way into such an environment.
Disclosure: Obviously I'm not a rocket scientist.