Explorer 1: America’s First Space Satellite

Explorer 1

Explorer 1 – Source: NASA

You probably know that Russian Sputnik satellite was the first human-made satellite to be placed into orbit. If not, I’m guessing you’ve at least heard of it. While the Russians beat the United States in that first declaration of space dominancy, America wasn’t far behind. Today we learn the story of the United States’s first orbital satellite: Explorer 1 1.

Towards the end of 1957, news of the Russian’s space accomplishments was rocketing around the world. Their successful Sputnik spacecrafts had recorded new entries in world history: Sputnik 1 was the first human-made object put into Earth orbit; and Sputnik 2 carried the first living creature larger than a microbe, a poor dog sacrificed in the name of science, named Laika.

The United States’s credibility was in question. Could the US compare to the Russian’s space prowess?

News of Sputnik’s milestones kickstarted an otherwise stalled United States space satellite program. The United States Army Ballistic Missile Agency (ABMA), directed by Wernher von Braun, teamed up with the federally-funded research facility, JPL (Jet Propulsion Laboratory) under the direction of Dr. William H. Pickering. JPL designed the Explorer 1 craft, while the ABMA modified one of its Jupiter-C rockets (gaining the designation Juno 1) to carry Explorer 1 payload into orbit.


A few months prior, in December of 1957, the United States Navy had attempted to put the first US satellite in orbit. That rocket made it about four feet above the launchpad before failing catastrophically in a magnificent ball of fire. Its failure earned such laughable nicknames as: Flopnik, Stayputnik, Oopsnik, and my favorite, Kaputnik.


Rapid work began on the satellite and launch system, and in only 84 days they had completed the design, construction, and assembly of Explorer 1 and its complementary rocket.

Explorer 1 schematic

Explorer 1 schematic – Source: NASA

Explorer 1 consisted of two major components: the 37.25 inch scientific portion, containing science and communication instruments, mated to a 45.5 inch rocket booster. This package was placed atop the 70-foot-tall Juno 1: a four-stage, Redstone-family booster rocket.

Explorer 1 launched from Cape Canaveral, Florida, at 10:48pm local time on January 31, 1958.

Explorer 1 entered an eccentric orbit around Earth, with the closest point in its orbit at 358 kilometers (222 miles) and its furthest at 2,550 kilometers (1,580 miles). It completed an orbit every 114.8 minutes. Mercury batteries powered the craft’s high-power transmitter for 31 days, with the low-power transmitter operational for 105 days. Explorer 1’s final transmission was received on May 23, 1958. The silent Explorer 1 continued to orbit for more than 12 years, its orbit finally decaying to the point of re-entry and destruction in the atmosphere over the Pacific on March 31, 1970. By then, it had completed more than 58,000 orbits.

Explorer 1 effectively initiated the Cold War space race. But it did more than just prove that the United States could compete with the Russians in putting things in orbit. Explorer 1 conducted real science and made some important discoveries that would be important to understand as the world progressed into a space-faring society.

Explorer 1 contained two main scientific instruments: one for detecting cosmic rays, and another for studying micrometeorites.

The micrometeorite package consisted of a “wire grid (arrayed around the aft section of the rocket body) and an acoustic detector (placed in contact with the midsection)“. Over the course of the experiment, 145 micrometeorite hits were detected.

The cosmic ray detection equipment made even greater discoveries. This was accomplished by an “Anton 314 omnidirectional Geiger tube detector“, which measured the flux of charged particles hitting the detector. The experiment was overseen by Prof. James A. Van Allen.

A peculiarity was noted in this experiment: the expected radiation count was approximately 30 per second, but the detector would occasionally return a result of zero. It was determined that these zero count intervals coincided with altitudes greater than 2,000 kilometers (1,200 miles). Further research determined that at those altitudes, the detector was actually being over-saturated and overwhelmed by the radiation. This led to the discovery of an energetic belt of charged particles that surround magnetized planets , such as Earth. This belt was named after James Van Allen, and today are known as Van Allen radiation belts. Knowledge of this region would become essential to the survival of humans that would travel through them in later space programs. The discovery was designated as one of the greatest of the International Geophysical Year.

William Hayward Pickering, James Van Allen, and Wernher von Braun at a press conference announcing the orbital insertion of Explorer 1.

William Hayward Pickering, James Van Allen, and Wernher von Braun at a press conference announcing the successful orbit insertion of Explorer 1 – Source: NASA

At around 1:00 am on February 1, 1958, just hours after Explorer 1’s successful orbit insertion was verified, William Hayward Pickering, James Van Allen, and Wernher von Braun were ushered to the National Academy of Sciences building in Washington, D.C.  to conduct a press conference that would make headlines around the globe.

That press conference produced one of the most iconic images of the Space Age. In the image, Pickering, Van Allen, and von Braun stand triumphantly, holding a model of Explorer 1 high above their heads.

A Moment in Time: Explorer 1 – Each of these three men thus represented a component of Explorer 1’s success: the rocket, the satellite and the science payload. Each represented an institutional underpinning crucial to the fledgling American space program: the Army, the Jet Propulsion Laboratory and scientific research as represented by the University of Iowa. Each had converged from his own path to the singular moment depicted in the triumphal image.

 

The success of Explorer 1 can’t be overstated. It proved the efficiency that could be achieved through collaboration between civilian and military agencies, it was one of the major sparks that ignited the Cold War space race, and it confirmed the United States as a powerful contender to the Russians.

  1. At the time of launch, also designated as Alpha 1958

The Pioneer Plaque: Our Calling Card to the Cosmos

In 1972 and 1973, Pioneer 10 and 11, respectively, left planet Earth with one-way tickets out of the Solar System. These two pioneers (heh) explored Jupiter, Saturn, and their associated moons before heading out into the great unknown on an uncharted interstellar voyage. Each of them carried a plaque, dubbed the Pioneer Plaques, and that’s what this story is about.

Eric Burgess, science correspondent for the Christian Science Monitor, recognized that by being the first spacecraft designed to leave our Solar System, it too would be planet Earth’s emissary to the stars. He believed the Pioneers should contain a message from its creators, one that could serve as an introduction and greeting from any being that might make contact with the Pioneers thousands or millions or more years from now. This thought spawned the idea for what became the Pioneer plaques. Burgess approached Carl Sagan, who was at NASA’s Jet Propulsion Laboratory in Pasadena, CA, working in connection with the Mariner 9 program. Sagan was thrilled with the idea and agreed to promote the idea with NASA officials.

Two identical plaques were made–one for Pioneer 10 and one for Pioneer 11. They are 9 inches by 6 inches, .05 inches thick, and constructed of gold-anodized aluminum. They were constructed and engraved by Precision Engravers of California, a company that is still in business today and sells replica plaques. The design itself was created by Carl Sagan and Frank Drake, with the artistic help of Sagan’s then-wife Linda Salzman Sagan. NASA accepted the idea and their design, and received approval to have them flown aboard Pioneer 10 and 11. They would be attached to the craft’s antenna supports, positioned such that they would be protected from erosion caused by interstellar dust.

The design consists of a few different elements symbolizing humanity’s place within the galaxy, and information about our species.

The Pioneer Plaque

Beginning in the top-left is a schematic representing the hyperfine transition of  neutral hydrogen.Hyperfine transition of neutral hydrogen extracted from the Pioneer plaque

Wait! Don’t go! Give me a chance to try and unpack that gobbledygook for you. 

This piece of the plaque is actually kind of important, because it serves as a reference for the other elements of the plaque. For this explanation, consider that the electrons in atoms exist in one of two states: spin up and spin down. Hydrogen was chosen for the diagram due to it being the most abundant element in the Universe as well as one of the simplest, containing a single electron. Basically, the magnetic field of an electron can either be oriented parallel to the magnetic field of the atom’s nucleus, or it can be oriented in the opposite direction. These are the two states I referred to. The diagram shows both of these phases connected by a line that represents the transition–a hyperfine transition I might add–between these two states. When this occurs, a photon is emitted with a specific wavelength of about 21 centimeters and a frequency of 1420 MHz. A being that might one day come into contact with the plaque would hopefully understand the distance and frequency represented, for if they could they would then be able to use it as a reference for the other diagrams on the plaque.

Like, for example, the diagram of us.

Depiction of humans on the Pioneer plaque

 

Here, the plaque depicts a nude male and female human. To the right of the woman figure are hash marks indicating the top and bottom of her height. Between those marks is the symbol “| – – -“, which is the binary symbol for 8. The woman is 8 tall. 8 what, you’re asking? 8 feet? 8 inches? Remember when we created our scale using the hydrogen transition thingamajig, and came up with 21 centimeters? That’s right, the woman is 8 x 21 cm, which equals 168 cm (just a skosh over 5′ 6”). Make sense?

There have been claims made that the original drawing had the man and woman holding hands, but that a conscious decision was made to separate the two out of concern that an alien gazing upon the plaque would think of the two humans as a single being. There are also rumors that the original design included a more anatomically-correct woman body, but that single extra line needed to be erased to garner top NASA official authorization.

What a wonderful time to have been around JPL for those discussions. There’s a lot we can learn about ourselves within a debate on how to present ourselves to alien beings thousands or millions of years into the future.

Moving on…

Silhouette of the Pioneer spacecraft relative to the size of the humans.Behind us (the humans), there’s a silhouette of the Pioneer spacecraft, showing the relative size of humans to the craft. I guess this is there in case the aliens are too lazy to do the hydrogen transition conversion thing we just talked about.

At the bottom of the plaque, we have a depiction of our solar system and where Pioneer came from. Also, more hash marks. I hope the aliens realize that this time they’re supposed to be multiplying by 1/10th of the distance of Mercury’s orbit from the Sun, and not 21 cm like they were to do with the human models. If not, they’ll have a hard time finding us if they’re looking for tiny planets that have orbits mere hundreds of centimeters from their star. I really hope aliens enjoy puzzles.

 

The Solar System with the trajectory of the Pioneer spacecraft.

 

I also hope that by the time they see this part of the plaque that word hasn’t gotten to them about Pluto being downgraded to dwarf planet….

But ours is only one of millions of solar systems within our corner of the galaxy. Providing a map of our solar system won’t help them if they have no way to find it to begin with. That brings us to the next part of the plaque:

800px-Pioneer_plaque_sun

This schematic shows the location of Sol (our sun) relative to the center of the Milky Way and 14 pulsars. I’m going to spare you the technical details and give you the bare bones version. The length of the lines indicate the relative distance between the Sun and the various pulsars. The long binary numbers give the periods of the pulsars, basically their signature. One thing worth noting about the periods of the pulsars, is that their frequency will change over time. Knowing this, a being deciphering this part of the plaque would be able to not only figure out where in the galaxy the Pioneers originated from, but also when they left Earth. Depending on where the plaque is encountered, only some of the pulsars might be visible thus the redundancy of including 14. This should be enough to allow for triangulation back to us. There’s a 15th line coming out of the center of the figure (which, if you haven’t guessed already is where the Sun is located); it’s the long one pointing to the right. It shows the relative distance from the Sun to the center of the Milky Way galaxy.

So there you have it. The Pioneer Plaque: a representation of humans and their size, a celestial map to the place and time the craft and its plaque originated from, and a tool to use as a standard unit of measure to decode all of the details.

If only we put so much effort into the selfies we post of ourselves on Facebook.


Waiting For Curiosity

Even though there’s still just under five months remaining until the Mars Science Laboratory Curiosity rover lands on Mars’ surface, I almost find myself counting down the days. I woke up early to watch the launch of MSL live on NASA-TV last November and have followed the updates on its progress since then. One of the neat features you can find on the MSL website is the “Where Is Curiosity?” page, where simulated views of its progress from Earth to Mars are updated daily over its 36-week journey.

Watching the slight change in the images from day to day gave me an idea: these images could be made into a cool animation! So I hopped over to the Jet Propulsion Laboratory/California Institute of Technology’s Solar System Simulator website, fiddled around with the various options, and then started collecting images for each day that the mission has been elapsed up until today. I put them together into a little video, added some music, and now I offer it to you for your interplanetary enjoyment.

In the top left, you can watch the days tick by. The MSL is labeled in green in the center of the video. If you’re interested in reading some of the details related to distance traveled and the speed of the craft, you’ll want to watch the video in HD and full-screen.

You’ll probably notice that around 14 seconds into the video (specifically, beginning with the frame for January 14), the perspective changes slightly. I’m not exactly sure what causes it, but its the way the simulator changed the images it spit out starting with that date. I’m going to contact the designer with JPL/Caltech and see if they can help me out with different perspectives. I hope to update it from time-to-time between now and August, to put Curiosity’s progress in perspective.


And Curiosity is Off!

Screencap of MSL launch

At around 10am EST (7 PST) this morning, the Mars Science Laboratory carrying the Curiosity rover, lifted off from NASA’s Kennedy Space Center in Florida. The powerful Atlas V rocket had no hesitation after it ignited and propelled the MSL off of the launchpad. Within a few minutes, the MSL was in orbit. 44 minutes after launch the spacecraft separated from the rocket putting it on a trajectory to reach Mars in August of 2012.

Good travels, Curiosity!

Mars Science Laboratory

Curosity on Mars - Artist's concept

Credit: NASA/JPL-Caltech


As you most likely know, we’re just a day away from the planned launch of the Mars Science Laboratory. Curiosity is scheduled to launch on Nov. 26, 2011, at 10:02a.m. EST (7:02a.m. PST) for an eight-month, 570 million kilometer (354 million mile), trip to the red planet. Curiosity will launch from on top of an Atlas V rocket, one of the largest rockets currently available for interplanetary travel. The launch window exists from now until December 18, 2011, but as of today the current weather forecast shows a 70% chance for good weather come launch time.

NASA will be providing coverage of the launch both online and on NASA TV, with launch coverage beginning at 7:30am EST (4:30am PST).
Check out this video for an animated look at some of the mission milestones. (The animation is very cinematic and has what sounds like a Jason Bourne-themed score.)

Stay tuned to 46BLYZ.com for future coverage of the Mars Science Laboratory.