Then:
The deployment and usage of satellites and space probes
hadn’t started until a surprisingly long time period of five decades ago.
Before then, we did not have access to rockets powerful enough to launch
something out of our planet’s atmosphere and into space. That changed after
World War II, however, and soon afterwards the Union of Soviet Socialist
Republics, more commonly known as the Soviet Union, launched the world’s first
ever satellite, dubbed Sputnik I, into space on October 4, 1957. Despite being
the first satellite, it did little other than beep periodically, yet the fact
that it was a man-made satellite in space that was not the United States’
property was enough to kick our own space program into gear. Not even half a
year later, the United States launched the first American satellite, dubbed
Explorer I, into space on January 31, 1958 (space exploration 2016). Explorer I
was understandably simple in comparison to the satellites and lunar probes that
we launch in our current day and age, yet they were far from just useless
displays of a country’s ability to launch chunks of metal into the void
surrounding our planet.
It
is impressive just how much information we managed to squeeze out of Sputnik I
during its time spent in orbit. Consisting of what equated to a 184-pound metal
beach ball armed with a radio transmitter that was only capable of transmitting
meaningless “deep beep-beep” sounds back to Earth (Dickson 2001a), we were able
to learn about the density of the upper atmosphere solely through the drag that
Sputnik I experienced as its orbit slowly decayed. Said drag was caused by
Sputnik moving through the ionosphere’s plasma, and it was speculated that the
charge required to achieve this drag could be acquired in the area of our
atmosphere where the aurora borealis phenomena takes place (Warwick 1959).
Alas, Sputnik was only able to help gather “basic” information like this until
it burned up and was destroyed during re-entry. Thankfully for the United
States, our first satellite was launched with proper sensors and as such was
able to relay back to us data more complex than the density of our upper
atmosphere. One of the most important discoveries Explorer I would have to be
the discovery of the Van Allen radiation belt, and it continued to relay data
on it for roughly four months before its batteries finally ran dry. The
satellite continued to orbit the Earth until 1970, where it finally re-entered
the Earth’s atmosphere (Dickson 2001b). It is interesting how the powerless
mass of metal managed to remain in orbit for around 12 years, but I will touch
on that later. |
| Despite looking just like the original, the real Sputnik I burned up in the Earth's atmosphere. |
Now:
We have made leaps and bounds in technological
advancement in terms of satellites since the days of Sputnik I and Explorer I.
As such, I feel that it would not hurt to go over the basics of satellites as
they are now. According to Paleo, a satellite is “an airborne autonomous
platform that carries a set of sensors to capture information on the surface of
the earth, including vegetation, water masses, ice, and the atmosphere” (Paleo
2007). Satellites do more than just examine the Earth from up above, of course.
They can also turn their attention to the distant planets and stars, even
wandering out into the void to do so. They then technically become
interplanetary probes, but seeing as how those are basically a subgenre of
satellites I believe it is worth mentioning. Back on track, there are two kinds
of sensors found on modern satellites: passive and active. Passive sensors are
in charge of capturing the energy that is reflected by or emitted from a
certain geographical area and of a certain wavelength; this is what is used to
create an image of what is being captured. Active sensors send energy to the
surface of the planet and then transmit whatever is bounced back to them. In
general, active sensors are superior to passive sensors in terms of
reliability; active sensors are not affected too much by weather due to using
microwaves, whereas passive sensors are strongly limited by excessive amounts
of clouds like those in storms (Paleo 2007).
As
for the types of satellites, there are three major ones: space probes, weather
and observational satellites, and communications satellites. I already touched
on space probes earlier; they function like regular satellites, yet instead of
orbiting the Earth they wander the solar system and sometimes beyond to gather
information that would normally be impossible to access. Weather and communications
satellites share the similar trait of geosynchronous orbits, which in simpler
terms means that they orbit in a way so that they are constantly positioned
over a specific area of land. This practice is invaluable for weather
satellites, for it is how weather channels are able to provide hour-by-hour
weather time lapses; it would be a little more than awkward if one of said time
lapses started in Michigan and ended in Wisconsin, now would it not? Being
geosynchronous benefits communications satellites since it would be problematic
if they wandered while transmissions were sent to or received from them. As for
how communication satellites work, they have signals sent to them by stations
or other locations and then reflect those signals to receiving stations or
antennae. In either case, they are relayed to the consumer in the form of
television or other form of media (Satellite transmission 2015). |
| Informative imagery such as this would be impossible if it were not for weather satellites. |
Later:
Not even a day ago I saw the descent of a satellite
through the Earth’s atmosphere get mentioned on television. The satellite had
already broken up into several pieces on the way down, with each piece engulfed
in flame and leaving a brilliant trail of light and smoke. This is normally the
fate met by satellites that outlive their usefulness: falling through the sky
in a fireball reminiscent of a shooting star. Given how much surface area of
the Earth is either uninhabited land or open ocean, most of the scrap metal
that survives the descent ends up landing away from civilization. There are a
few unlucky exceptions, however, such as the case of a particular home in the
United Kingdom. One day in the July of 2009, an extremely hot, four-pound chunk
of metal hurtled through the sky and crashed into a home in the town of West
Hull, piercing the roof before stopping in the home’s attic. The owners of the
home were assured that it was most likely a piece of a decades-old satellite
that somehow survived re-entry, but the damage was done (Ernstein et al.,
2012). In the future, we could find ourselves having to launch more satellites,
and more satellites means more man-made meteoroids flying through the sky on
their gradual but inevitable re-entry into our atmosphere. The odds of one of
them hitting something is rather slim, but with more satellites you have more
dice rolls and at least one of those rolls will eventually be a “winner”.
Abandoned
satellites are not only a danger when they re-enter the atmosphere; they pose
an equal, if not greater, risk to other satellites and manned space stations
while above the atmosphere. Collision with a functioning satellite could very
well put the unlucky satellite out of commission, and such damage caused to
manned space stations is scary because of both this and the potential loss of
life. Such a situation almost occurred in 2009 when the International Space
Station was “buzzed” by a chunk of debris. At around five inches in size, it
was like a makeshift cannonball travelling at speeds high enough that it would
have burned up in the Earth’s atmosphere if and when it dipped lower. Some are
able to celebrate the existence of this debris as relics of history, yet this
debris is more than capable of killing an astronaut or puncturing a space
station if either is in the wrong place at the wrong time (Ernstein et al.,
2012). Again, this problem could be exacerbated in the future if and when we
launch more satellites into orbit. I cannot help but think of WALL-E in this
case; fictitious as it may be, having even a fraction of the movie’s amount of
space debris in orbit is very concerning. As a countermeasure, perhaps
satellites could be armed with explosives so that once they serve their
usefulness, they could be reduced to smaller, easier to burn fragments of
metal. This will take a lot of consideration, however, because this also turns
something larger than that aforementioned cannonball into what is the
equivalent of a field of grapeshot going at a speed that rivals sound through a
vacuum until it starts to give in to the Earth’s gravitational pull. |
| Looks harmless now, right? How about when it's traveling as fast as a shotgun blast? |
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