GPS

GPS

    You already know this since it's basically everywhere, on your phone, in your car, even in those farm tractors.  Global Positoning System, a U.S. government owned and operated entity, launched its completion satellite just a few weeks ago, bringing the grid to a planned 24 orbiting satellites (30 are actually operating).  But how does it all work, this GPS?  How does it find you and guide you?  Magic?  Triangulation?  No, to both.  And there's another problem key to the system, one that NASA has discovered...the global part.  Somewhat concerning (but not thought of by those of us who aren't involved in space engineering) is what happens when we venture away from this planet, as in far, far away.  Every signal, every radio transmission, every adjustment and positioning signal, eminates from GPS, all of which comes from one place and one place only...earth.

    From Mars, a light or radio transmission can take from 3 to 22 minutes (one way), and Mars is relatively close at 140 million miles from earth.  Still pretty far to our minds, but to put it into persepctive, if our solar system were shrunk down to the size of a baseball park, says Edward Packard in his book Imagining the Universe, and our earth was the size of a baseball resting on home plate, our moon would be 7.5 feet away; the smaller planet Mars, however, would rest 1.5 miles outside the ballpark.  Back to real dimensions, that translates into what is close to a 3 year roundtrip space flight.  What if something goes wrong en route, or a part fails, or oxygen is getting low...send message, wait 30 minutes or more (at least, you hope the transmission is that fast), and hope that a solution is coming (allowing time for engineers on earth to figure out the problem).  But there's more...with just 1% of earth's atmosphere, everyone from geologists to microbiologists are anxious to find what awaits humans once they land on Mars.  Imagine the new forms of bacteria and land formations...or can we?

   The Curiosity rover now on Mars (the next rover isn't due to land until 2020) was thoroughly scrubbed and disinfected by NASA before launch, subject to hydrogen peroxide baths for an hour, blasted with ultraviolet light, baked and dosed with high Ph concentrations.  At the end, scientists still found over 56,000 organisms from 377 bacterial strains that survived it all.  One strain was Gracilibacillus, a bacteria found on Martian soil and one that basically eats rocket fuel.  Other strains can survive sodium hydroxide (lye), excessive salt, lack of water and other conditions that might be present on the Martian landscape.  For geologists, the Rover is headed for Mount Sharp, a 5,500-meter-high peak.  Jim Bell, one of the lead researchers guiding the Rover told Discover: “We’re inside of a big hole in the ground — a crater created by an asteroid 4 billion years ago — and for some reason there’s a giant mountain in the middle...The top of the mountain goes higher than the walls of the crater. How does that happen?..The dust grains are microns in diameter, cigarette-smoke size. Imagine blowing smoke at a rock; nothing is really going to happen, but blow smoke at a rock for a billion years?  Dust and sand grains can carve canyons out of mountains — that’s a new thing for geology.”   One scientist, Steve Benner, told Discover that "about a kilogram of Mars lands on Earth every day."

    So backing up a bit, what does all of this have to do with GPS?  For one thing, should a satellite slide behind a planet, communication goes down since the signal to earth is blocked.  This happened in 1998 when the $25 million Climate Orbiter went behind Mars and never came out (the error was in the software, the English units having not been converted to metric units).  But for the oldest GPS satellite in space, the USA-66, orbiting over 20,000 kilometers away from our planet (the International Space Station, by comparison, orbits at 400 kilometers), our old Deep Space Network of radio antennas transmitting and receiving data (the system is now 50 years old) is simply overused and too slow...1.5 gigabytes of data sent from Mars can take six hours to download.  Already, NASA has a satellite using laser transmissions to send data optically, speeding up the transmission by 10 times (the test satellite is currently orbiting our moon).  But again, when the satellite's view is blocked, communication ends.  So imagine a signal far, far away, a signal so faint that it's "20 billion times lower than the power required for a digital watch," which is the signal sent from Voyager at the edge of our solar system.  Can we possibly venture any further, and if so, how will we lock in a navigational signal to let us know where we space explorers are? 

    NASA may have a potential solution, according to Wired, a system titled Deep-Space Positioning System or DPS.  Here's a small part of NASA's toned-down talk to non-engineers: JPLs deep-space positioning system (DPS) consists of narrow- and wide-angle cameras, a coelostat, an S- or X-band receiver and patch antenna, and a central processor that hosts the navigation computations and controls the coelostat.  The DPS instrument determines the location of the hosting spacecraft via images of solar system objects and, optionally, via one-way radio to the Earth or another known object from which Doppler observables are extracted.  Did you catch the word "optionally?"  Communication with Earth would be optional with the new proposed system.

   In Greg O'Brien's book, On Pluto, he wrote: The Kuiper Belt is an elliptical icy plane far outside the orbit of Neptune and billions of kilometers from the sun.  It is a long way from Ireland's Ring of Kerry.  The Kuiper Belt was formed from fragments of the Big Bang, spin-off from creation of the solar system, and is home to dwarf planets like Pluto, Haumea (named after the Hawaiian goddess of childbirth), Makemake (the god of fertility of the native people of Easter Island), trillions of anonymous objects, and the mysterious Oort Cloud, a suspected source of comets that flash about our sun.  Here, deep in the cosmos, Sedna orbits--the first observed body belonging to the inner Oort Cloud.  This remote expanse holds the answers to life.  Of course (as mentioned in my earlier post), author O'Brien was using the metaphor to describe Alzheimer's, "...the asteroids, dwarf planets and the Oort cloud of this disease refract reality.  One is left with random manifestations, successions of real-time, mind-bending warning ciphers that serve only to confuse, yet underscore the progression of a beast that attacks without forewarning."  But key to his point was the distant communication, the weak signal trying to get through, struggling, yet somewhere out there holding "the answers to life."

    Some people, some talented engineers and some battling Alzheimer's, are looking well past our planet, stepping willingly or unwillingly into the void.  They are going behind the planets and thus temporarily losing communication with us, but are also now looking for a new form of navigating into the unknown.  Both sets of personalities take courage, and in most cases, money.  But before we discount their efforts, we may just want to remember just how the rest of us are truly tied to this planet.  Looking elsewhere for another home might sound well and good, but we've got a lot to figure out first, our tether rope expending only so far.  Satellites and GPS might tell us where we are...but where are we really?