Posted on 01/31/2004 12:54:39 PM PST by optimistically_conservative
As the first explorers pushed into the interior of the New World, they found native populations reeling from diseases never seen in the Americas.
The bugs got there first. Leapfrogging ahead of the Europeans, the microbes carrying smallpox, measles and other diseases had decimated communities that had no natural immunity to them.
Now, on a more distant new world, the bugs have done it again -- across 50 million miles of interplanetary space. Decades will pass before the first humans set foot on Mars. But they won't be the first Earthlings to land there.
At six landing sites and a dozen other spots where spacecraft or spacecraft parts have crashed, Earthly microbes -- hitchhiking on U.S., Russian and European spacecraft -- likely have tenuous toeholds on the Red Planet. Three more beachheads have been added in the past month -- the two U.S. rover landing sites and the apparent crash site, location still unknown, of Europe's Beagle 2 lander.
No one expects Earth bugs to take Mars by storm. Some experts question whether they can survive at all. Mars is cold and dry. And its thin carbon dioxide atmosphere provides little protection against incoming ultraviolet radiation, which is unkind to life as we know it.
Primitive life forms, however, have continually proved more resourceful than scientists once thought.
"When the Viking spacecraft reached Mars in 1976, we didn't know that life could thrive in hydrothermal vents in the oceans of Earth," says NASA's John Rummel. "And it's only recently that we've discovered signs that Mars' polar regions may have hanging glaciers with water at the base."
As the agency's planetary protection officer, Rummel is responsible for making sure that terrestrial organisms don't get a chance to colonize other planets -- or vice versa.
"We've already had some surprises and I would be surprised if there weren't more of them," he says. "We don't yet know a lot about Mars and ignorance is not bliss. We have to be conservative about what we do."
NASA has some reason to be concerned.
In 1969, when the Apollo 12 astronauts retrieved a camera from the unmanned Surveyor III, which had landed on the moon earlier, NASA scientists reported finding a colony of Streptococcus mitis. The bacteria were still viable, despite 2 1/2 years without nutrients or water in a near vacuum, exposed to radiation and temperatures of 250 degrees below zero.
Rummel says the report was never vetted in peer review journals of the time, and NASA currently contends that the contamination occurred after the camera was back on Earth.
To prevent interplanetary hitchhiking, the U.N. Space Treaty of 1967 set up "planetary protection" policies that are still in force but have received little public attention since the Apollo moon landing program ended.
Potential impediment
As morally repugnant as contaminating other planets might seem, scientists are more concerned that any microbial invaders might confound future efforts to detect locally grown life elsewhere in the solar system. Recent missions show that the official concern is undiminished.
The chance that the Galileo spacecraft might crash on one of Jupiter's moons and contaminate it with terrestrial organisms prompted NASA last year to send the $2 billion spacecraft on a self-destructive plunge into Jupiter's swirling atmosphere.
When it was launched in 1989, no one decontaminated the spacecraft because Jupiter and its moons were considered uninhabitable. But Galileo found what appears to be an ocean of water under the icy crust of Jupiter's moon Europa and NASA worried that crash landing there might seed the ocean with terrestrial microbes.
NASA is even more concerned about earthly bugs getting on Mars, the planet most like Earth in the solar system.
As with previous missions, the space agency took great pains to ensure that its rovers, Spirit and Opportunity, met international decontamination standards before they were launched last summer. At a cost of $3.8 million, a team of planetary protection engineers from the Jet Propulsion Laboratory spent weeks in the clean rooms at the Kennedy Space Center, preparing the rovers for their journey.
"These things are sanitized like you wouldn't believe," says Mars rover team member Matthew Golombek. "By the time they're launched, they are cleaner than your baby when you wash it."
JPL engineers completely disassembled both rovers. Parts that could withstand high temperatures were baked at 240 degrees. Heat-sensitive components were irradiated with ultraviolet light or swabbed with hydrogen peroxide. Then workers in clean-room "bunny suits" reassembled the rovers and sealed them in the spacecraft.
"We work pretty hard to keep our spacecraft clean, but we can't get everything," says JPL planetary protection engineer Laura Newlin.
NASA guidelines permit up to 300 bacterial spores per square meter of a spacecraft's surface -- cleaner than most surgical instruments. But many more organisms go along for the ride inside electronic components which, under ordinary circumstances, would never escape into the Martian environment.
When a spacecraft crashes, however, the chances of contamination go up.
NASA engineers say the crash of its 1999 lander somewhere near Mars' South Pole could have released up to 700 million terrestrial spores.
Return trip a risk
Other crashes, including the loss of Europe's Beagle 2 in December and a number of Russian probes, may have had similar results. NASA officials are also concerned about the prospect of alien microbes getting loose on Earth.
Science fiction writers have repeatedly milked the dramatic possibilities of alien bugs -- from the extraterrestrial microbes run amok in "The Andromeda Strain" to H.G. Wells' "War of the Worlds," which had invading Martians felled by "the putrefactive and disease bacteria against which their systems were unprepared."
Not everyone is convinced that such risks are fictitious. One of them is University of Illinois microbiologist Carl Woese, who played a key role in changing the way scientists look at life on Earth.
Woese helped classify a group of organisms called archaea -- a previously unrecognized third branch on the tree of life -- which have a very simple genetic makeup and exist primarily in "extreme" environments thought to represent the early environment on Earth.
"When the entire biosphere hangs in the balance, it is adventuristic to the extreme to bring Martian life here," he says. "Unless you can rule out the chance that it might do harm, you should not embark on that course."
Whether there is any extraterrestrial life is still an open question. Scientists thought they saw hints of primitive Martian life in a Martian meteorite a few years ago, but doubters have carried the day.
Whether Earth is ready or not, however, extraterrestrial material is on its way. In September, NASA's Genesis spacecraft will return to Earth with the first samples of matter from the solar wind, believed to be similar to the matter from which the solar system formed. It will be the first material returned from space since the Apollo program.
And in January, NASA's Stardust spacecraft scooped up microscopic bits of dust from the Comet Wild 2 for return to Earth in 2006. The comet dust will parachute to a landing at an Army test range in Utah.
Special laboratory
Both the solar wind matter and the comet dust will be taken to NASA's Lunar Receiving Laboratory in Houston, where the moon rocks collected by Apollo astronauts are curated.
Starting with a robotic landing on Mars to scoop up and return rock and soil sometime after 2011, future sample returns will require a laboratory that can not only prevent the escape of any microbes in the samples, but assure that they aren't tainted by earthly organisms.
Although the Houston space center has the most experience in operating such a facility, a panel of the National Research Council suggested three years ago that the need for biological containment might make it better suited for location at the Centers for Disease Control and Prevention in Atlanta or at the Army's biological warfare laboratory in Fort Detrick, Md.
NASA is expected to announce sometime next month what features the facility must have. Rummel says the location is yet to be determined and the cost, although still uncertain, could be from $20 million to $50 million.
NASA, of course, quarantined the Apollo astronauts returning from the moon, just in case they'd brought back some exotic organism.
Biologists were horrified when recovery crews departed from the carefully laid plan and opened the door of the Apollo 11 capsule while it was bobbing in the ocean. Years later, astronaut Buzz Aldrin said he developed his own doubts about the value of the three-week isolation period when he noticed ants crawling into the quarantine trailer.
"The containment procedures in place then were laughable and we'll have to do better with the Mars samples," says NASA astrobiologist Michael Meyer. "Of course, the moon was a very unlikely place to find something that was going to infect the Earth," he says. "There's only an outside chance that we'll find anything like that on Mars, but the possibility is not zero."
Sad.
What I would like to know is: "Did we send the very best?"
"Take us to your leader decontamination chamber."
This is a red flag.
When logic has broken down a position with the truth, the looser always whips this argument out.
Beyond that, it is unlikely that Earth-evolved disease organisms could infect native Martians even if such existed. This business of adaptation works both ways. At the time of their introduction into the Americas, the organisms that cause smallpox and measles were already well adapted to infect human beings.
If we have already contaminated Mars, how do we know whether it is a good sample or not. If we bring it back without contaminating it in the process but find our own stuff there anyway, how can we prove it didn't get contaminated post collection.
Everyone knows that this Mars exploration is just about finding oil for Haliburton, right?
The author overlooked the other route of Mars contamination. Every time the toilet is flushed on the orbiting Space Shuttle, the waste is freeze dried in the vacuum of space, and blown into the solar wind.
If Mars happens to be "down wind" of Earth during a mission, billions of fecal microbes could be captured by the planet. Since the solar wind averages about 300-600 km/sec. The microbes would arrive at Mars in a few days.
Actually, that's what I was thinking.
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