Galileo Spacecraft: First Orbiter of Jupiter

Artist rendering of Galileo arriving at Jupiter

Artist rendering of Galileo arriving at Jupiter – Credit: NASA

Space Shuttle Atlantis carried a special payload during its STS-34 mission. Commander Don Williams and crew transported the Galileo spacecraft into Earth orbit, from which point it was launched on a years-long voyage to Jupiter. Galileo would become the first spacecraft to orbit an outer planet and would go on to reveal fascinating views of the gas giant and its moons, as well as make monumental discoveries about the nature of the Jovian system.


Quick Facts:

  • Launch Date: October 18, 1989, Shuttle Atlantis STS-34
  • Primary Mission: October ’89 to December ’97.
  • Extended Missions: 3, from ’97 to ’03.
  • Number of Jupiter orbits: 34
  • Total distance traveled during mission: 4,631,778,000 km (approx 2.8 billion miles)
  • Mission End: September 21, 2003

Getting Galileo to Jupiter

Work on the Galileo craft began in 1977, after the exploration of Jupiter was listed as the number one priority in the Planetary Science Decadal Survey published in 1968. Fly-bys of the massive planet were conducted by the twin Pioneer 10 and 11 and Voyager 1 and 2 spacecrafts, but Galileo was set to do more than just perform a fly-by. It would launch an instrument-laden probe into Jupiter’s atmosphere, and then continue to orbit the planet for years. This mission would provide knowledge of the Jupiter system that could hardly even be imagined.

Galileo deploying from Shuttle Atlantis

Galileo deploying from Shuttle Atlantis – Credit: NASA

Galileo suffered a number of postponements. The first planned launch was to be from Space Shuttle Columbia in 1982, but development delays in the Space Shuttle program made that early of a launch unfeasible. The upside is that this gave the Galileo developers more time to work on the probe. Further planned launches and postponements occurred in 1984, 1985, and 1986.

As we all know, 1986 was the year of the Challenger disaster. Galileo would be put on hold during the 32-month hiatus that followed the tragedy, as every detail of the Shuttle program was examined and made safer. Galileo was originally planned to be attached to a liquid hydrogen-fueled Centaur-G booster; however, new safety protocols following Challenger prohibited the booster from being carried in the Space Shuttle’s payload bay. Mission designers had to reconsider how they would get Galileo from the Shuttle’s low Earth orbit to Jupiter. They decided on employing a solid-fuel Inertial Upper Stage booster (IUS). Whereas the Centaur-G would have propelled Galileo on a short and direct trajectory to Jupiter, the IUS would take longer and also require some technical gravitational slingshot maneuvers to make it to the gas giant.

Galileo was finally launched from Space Shuttle Atlantis, during mission STS-34 on October 18, 1989. From there, its IUS booster was started and it began its unique “VEEGA”, or Venus Earth Earth Gravity Assist, maneuvers.

Galileo spacecraft trajectory

Galileo spacecraft trajectory – Source: NASA

  • Galileo flew by Venus on February 10, 1990 at an altitude of 16,000 km (10,000 miles).
  • It then flew by Earth on December 8, 1990 at an altitude 960 km (597 miles).
  • Its trajectory took it near Asteroid Gaspra on October 29, 1991, coming within 1,601 km (1,000 miles).
  • Then it was back to another Earth fly-by on December 8, 1992, this time at an altitude of only 303 km (188 miles).
  • On its way back towards the outer solar system it flew by Asteroid Ida on August 28, 1993, coming within 2,400 km (1,400 miles) of the asteroid.

On its way to Jupiter, Galileo was positioned perfectly to observe the doomed Comet Shoemaker-Levy 9 as it impacted the planet. Pieces of the comet, having been torn into fragments by Jupiter’s immense tidal forces, impacted Jupiter from July 16 – 22, 1994, on the side facing away from Earth. Fortunately, Galileo had a prime view and was able to record the impact. Earth-based telescopes could only observe the impact sites as they rotated into view a few minutes afterwards.

In July, 1995, Galileo released its atmospheric probe component. For the next five months, the probe and orbiter continued their cruise to Jupiter. On December 7, 1995, Galileo had arrived. The orbiter and probe diverged onto their separate missions.

Atmospheric Probe

On December 7, 1995 Galileo’s atmospheric probe sliced into Jupiter’s atmosphere at 47.6 kilometers per second (106,000 miles per hour). As the atmosphere began to slow the probe, it deployed its drogue and main parachutes and dropped its heat shield to expose its scientific instruments. The probe began recording data and transmitting it up to the main Galileo spacecraft orbiting high above, which then re-transmitted the data to Earth. The probe recorded 58 minutes of data on Jupiter’s weather and atmosphere. Towards the end of its descent, the probe measured wind speeds of 724 kilometers per hour (450 miles per hour). The intense heat and pressure of Jupiter’s atmosphere melted and vaporized the probe less than an hour into its journey through Jupiter’s atmosphere.

Orbiter

While the atmospheric probe’s job was complete, the Galileo orbiter still had years of work left to do. The orbiter received its electric power from two radioisotope thermoelectric generators (RTGs). That may sound complicated, but it’s really quite simple. These RTGs carry the radioactive element plutonium-238. As the plutonium decays, it releases energy in the form of heat. That heat can then be easily turned into electricity through the Seebeck effect. This type of energy generation is long-lasting and reliable, as well as impervious to the cold temperatures and strong radiation fields of the Jupiter system. Galileo carried two of these RTGs, with a combined total of approximately 22.7 kilograms (50 pounds) of plutonium-238. While these radioactive components had been used on previous space missions, Galileo drew extra concern due to it being both carried by the Shuttle as well as the multiple Earth fly-bys. Anti-nuclear activists protested Galileo’s launch, fearing a malfunction could cause radiation poisoning for many thousands of people on Earth. NASA, however, argued that the probability of risk was extremely low.

Jupiter's ring system, as observed by Galileo

Jupiter’s ring system, as observed by Galileo – Credit: NASA/JPL/Cornell University

Galileo conducted slow orbits of Jupiter, approximately 2 months long each. The orbits were elongated, and designed to bring the spacecraft within different distances to Jupiter, which allowed it to sample different areas of the planet’s magnetosphere. These orbits were also designed to bring Galileo and its instruments into close fly-bys of Jupiter’s largest moons. Galileo completed its primary mission on December 7, 1997; however, the craft was still functioning extremely well and was able to continue taking measurements and sending valuable data back to Earth. Its mission was extended three times, operating until 2003.

Volcanic activity on Io, as observed by Galileo

Volcanic activity on Io, as observed by Galileo – Credit: NASA/JPL

The orbiter made several discoveries during its mission:

  • It discovered a possible ocean under Europa’s icy crust
  • Revealed Ganymede’s very own magnetic field, the only moon known to have this feature
  • Made the first observations of ammonia clouds in another planet’s atmosphere
  • It created hundreds of images of Jupiter’s large ‘Galilean moons’: Io, Callisto, Europa, and Ganymede
  • It measured the high levels of volcanic activity on Io

Sagan Criteria for Life

The late astronomer Carl Sagan devised a set of experiments to be conducted by Galileo during its first fly-by of Earth. The purpose of the experiments was to see if life could be easily detected from a spacecraft. The results of the experiments were published by Sagan in 1993, in the scientific journal Nature. The experiments were a success, as Galileo was easily able to detect what are referred to as the ‘Sagan requirements for life’. These include strong absorption of light at the red end of the spectrum (indicative of plant photosynthesis), absorption bands of molecular oxygen (again, indicative of plant life), the detection of methane in the atmosphere (a gas created by either volcanic or biological activity), and the detection of narrowband radio wave transmissions (could indicate a technologically advanced civilization).


By the end of its mission, Galileo had conducted 34 orbits of Jupiter and had made multiple fly-bys of Jupiter’s moons: Io 7 times, Callisto 8 times , Ganymede 8 times, Europa 11 times, and one fly-by of Amalthea.

Due in part to Galileo’s discovery of potential oceans on Europa (and possibly other Jovian moons), the decision was made to end the orbiter’s mission by sending it to the same fate as the atmospheric probe eight years prior. Rather than risk contaminating (with either Earth bacteria or radiation from the RTGs) one of Jupiter’s potentially life-harboring moons, Galileo would be ordered to impact Jupiter. On September 21, 2003, Galileo entered Jupiter’s atmosphere at 48.2 kilometers per second (108,000 mph).

The Galilean Moons: Jupiter's four largest satellites

The Galilean Moons: Jupiter’s four largest satellites – Credit: NASA/JPL/DLR

The total mission cost was approximately $1.4 billion USD, had more than 100 scientist partners from many different countries, and involved the work of more than 800 individuals.

In spite of postponements, an antenna that failed to fully deploy, and a tape recorder malfunction, Galileo performed magnificently. It was a mission that brought us up close and personal with our Solar system’s largest planet and provided us with a much more detailed understanding of the Jovian system. Galileo paved the way for future studies of Jupiter and its moons. Its successor, the Juno orbiter, is currently en route and arriving in July of 2016, and plans are being considered to investigate Europa’s oceans. Like the astronomer that the spacecraft took its name from, Galileo Galilei, this mission revealed new worlds that we previously could only distantly wonder about.

 

Soyuz Spacecraft Returns to Earth: Year-In-Space Mission Ends

The image below shows the Soyuz TMA-18M spacecraft’s return to Earth, on March 2nd, 2016. Inside are NASA astronaut Scott Kelly, and Russian cosmonauts Mikhail Kornienko and Sergey Volkov. Both Kelly and Kornienko spent almost an entire year in space aboard the International Space Station, in a research effort to understand the health impacts of long-term spaceflight.

Soyuz TMA-18M spacecraft, floating back to Earth

Soyuz TMA-18M, floating back to Earth – Credit: (NASA/Bill Ingalls)

Click the image for an even gorgeous-er huge version.

Isn’t that image simply amazing?

In Memoriam: Captain Donald Edward Williams

Captain Donald Edward Williams

 

Captain Donald Edward Williams passed away on Tuesday, February 23, 2016. He was 74.

Early Life, Education, and Military Service

Donald Edward Williams was born on February 13, 1942, in Lafayette, Indiana. He grew up working on his father’s farm, spending his time after school running tractors, tending to animals, and completing general repairs. While working, he always took note of the jets flying overhead and thought to himself that being up there looked like a lot more fun that what he was doing down in the dirt. He graduated Otterbein High School, Otterbein, Indiana, in 1960 before earning a bachelor of science degree in Mechanical Engineering from Purdue University. At Purdue, he received his commission through the Naval Reserve Officers Training Corps (NROTC). He completed flight training in Florida, Mississippi, and Texas, earning his pilot wings in 1966.

Williams completed a total of  four deployments to Vietnam, aboard USS Enterprise, as a member of Attack Squadron 113 and Attack Squadron 97. During his deployments, he flew a total of 330 combat missions. After Vietnam, Williams enrolled at the Armed Services Staff College, graduating from the U.S. Naval Test Pilot School in 1974.

Williams was selected as a member of the NASA class of 1978, also known as Astronaut Group 8 or the Thirty Five New Guys (which, I must point out, included gals, too). This was the first new group of astronauts since 1969. He served in various capacities at NASA until being pegged to serve on two separate Space Shuttle missions:

STS-51-D

STS-51-D Mission Patch

STS-51-D Mission Patch

He served as pilot on Space Shuttle mission STS-51-D, which was completed on shuttle Discovery in 1985. That mission included completing a number of experiments (including some utilizing simple toys, with the results being shared with school students), and launching a couple of satellites. One of the satellites malfunctioned upon deployment. As a result, NASA authorized its first unscheduled 3-hour EVA (extravehicular activity).

According to the book, Discovery: Champion of the Space Shuttle Fleet:

The mission became an ingenious effort to avert failure by improvising a difficult rescue without prior training. As engineers and astronauts on the ground devised a solution, they sent instructions to the crew to use on-board materials to make something like a flyswatter and a lacrosse stick.

 

Additionally, that Discovery mission included the first elected government official to fly in space. Utah Senator Edwin Garn joined the crew as Payload Specialist 2, acting as a congressional observer to the program. (Talk about perks of the job!)

STS-34

STS-34 Mission Patch

STS-34 Mission Patch

Williams served as Commander of his second and final spaceflight in 1989, on mission STS-34 aboard shuttle Atlantis. A notable accomplishment of that mission was the deployment of the Galileo spacecraft, which became the first spacecraft to orbit and penetrate the atmosphere of an outer planet.

In a 2002 interview with Rebecca Wright, as part of a NASA Johnson Space Center Oral History Project, Williams reflected on the STS-34 mission:

I really enjoyed that mission probably even more so than the first because it was my goal to command a mission, first of all, and I got to do that. But secondly, because we knew that Galileo was going to be a lasting program as opposed to the first flight, [where] we deployed the two satellites, [but] it turned out to be a unique flight, too, because of the spacewalk. The Galileo mission we knew, if it was successful, the spacecraft was going to end up in orbit around Jupiter several years later and then there [were] going to be several years of data and images sent back. It was going to be a living, ongoing program, and we got to be a part of it. That was a really unique experience.

Post-NASA

Williams retired from the U.S. Navy, having earned the rank of Captain, and left NASA. He completed numerous projects as a Division Manager with Science Applications International Corporation before his retirement in 2006.

During Williams’s career, he earned the following special awards and commendations: The Legion of Merit, Distinguished Flying Cross, Defense Superior Service Medal, 2 Navy Commendation Medals with Combat V, 2 Navy Unit Commendations, a Meritorious Unit Commendation, the National Defense Medal, an Armed Forces Expeditionary Medal, the NASA Outstanding Leadership Medal, the NASA Space Flight Medal, the NASA Exceptional Service Medal, the Vietnam Service Medal (with 4 stars), a Vietnamese Gallantry Cross (with gold star), and the Vietnam Campaign Medal.

From his roots as a rural farm-boy with his eyes in the sky, to serving his country valiantly in four deployments during the Vietnam war, and finally having the honor to fly two space shuttle missions as a Pilot and a Commander, Donald E. Williams was a true American hero. He was among the best of the best and should serve as an inspiration for centuries to come. We thank you for your service and honor your legacy.

Godspeed, Mr. Williams.

NASA Astronaut Don Williams aboard Space Shuttle Atlantis

NASA Astronaut Don Williams aboard Space Shuttle Atlantis – Source: NASA

 

John Glenn’s Orbital Journey

On this day in 1962, the Atlas rocket boosters that John Glenn, inside his Friendship 7 capsule, was strapped to the top of ignited. Millions of Americans watched as the resulting 350,000 pounds of thrust vibrated the vehicle that was about to take the first American into orbit around the Earth.

CAPCOM (Capsule Communicator): 3… 2… 1… 0.
John Glenn: Roger. The clock is operating. We’re underway.

Launch of Friendship 7

Launch of Friendship 7, the first American manned orbital space flight. Astronaut John Glenn aboard, the Mercury-Atlas rocket is launched from Pad 14. / Source: NASA

Minutes later, John Glenn became the fifth human in space and the first American to enter Earth orbit. Previously, Alan Shepard and Gus Grissom became the first and second, respectively, Americans in space; however, John Glenn was the first American to reach the important milestone of completing orbits of the Earth.

For the next 4 hours and 55 minutes, John Glenn completed three orbits of the Earth, reaching speeds greater than 17,000 miles per hour. NASA was still concerned about the effects of spaceflight on humans and this was the longest one an American astronaut had been subjected to yet. John Glenn remarked a number of times during the mission that he felt just fine, and was rather enjoying himself.

Five minutes into the mission:

John Glenn: Oh, that view is tremendous!

View of Earth from Friendship 7

View of earth taken by Astronaut John H. Glenn Jr. during his MA-6 spaceflight. / Source: NASA

John Glenn witnessed three sunsets from space during the flight.

John Glenn: The sky above is absolutely black, completely black. I can see stars though up above.

John Glenn: This is Friendship Seven. At this, MARK, at this present time, I still have some clouds visible below me, the sunset was beautiful. It went down very rapidly. I still have a brilliant blue band clear across the horizon almost covering my whole window. The redness of the sunset I can still see through some of the clouds way over to the left of my course. Over.

Sunset from Friendship 7

Orbital sunset photographed by Astronaut John H. Glenn Jr. aboard the \”Friendship 7\” during his Mercury-Atlas 6 (MA-6) flight. / Source: NASA

From his fantastic vantage point, he observed dust storms and fires in Africa and the lights of Perth, Australia.

And then there was his “fireflies”, which he first noticed at about 1 hour and 15 minutes into the flight:

John Glenn: This is Friendship Seven. I’ll try to describe what I’m in here. I am in a big mass of some very small particles, that are brilliantly lit up like they’re luminescent. I never saw anything like it. They round a little: they’re coming by the capsule, and they look like little stars. A whole shower of them coming by.

They swirl around the capsule and go in front of the window and they’re all brilliantly lighted. They probably average maybe 7 or 8 feet apart., but I can see them all down below me, also.

CAPCOM: Roger, Friendship Seven. Can you hear any impact with the capsule? Over.

John Glenn: Negative, negative. They’re very slow; they’re not going away from me more than maybe 3 or 4 miles per hour. They’re going at the same speed I am approximately. They’re only very slightly under my speed. Over.

They do, they do have a different motion, though, from me because they swirl around the capsule and then depart back the way I am looking.

Are you receiving? Over.

There are literally thousands of them.

These “fireflies”, as Glenn called them after the mission, were later determined to be ice crystals that would accumulate on the craft on the dark side of the Earth and then begin to break off of the capsule when the Sun’s heat returned. 1

Back on the ground, serious considerations were being made. A flight controller received a warning from a sensor on Friendship, indicating a loose heat shield. If the sensor was correct in its reading, the only thing holding the heat shield in place was the straps from the retrorocket package. After debate, a decision was made; Glenn was instructed to refrain from jettisoning the retropack — a normal procedure for re-entry — in hopes that it would hold the heat shield in place during re-entry; the alternative was the craft and Glenn disintegrating in the Earth’s atmosphere. Control offered no explanation for the procedure until after successful re-entry. Glenn suspected a problem with the heat shield, but remained focused on the parts of the craft he could control.

CAPCOM: This is Texas Cap Com, Friendship Seven. We are recommending that you leave the retropackage on through the entire reentry.

John Glenn: This is Friendship Seven. What is the reason for this? Do you have any reason? Over.

CAPCOM: Not at this time; this is the judgment of Cape Flight.

The sensor ultimately proved to be faulty and the heat shield remained securely attached to Friendship. 2

Aside from using more fuel than expected for attitude corrections, a hot spacesuit that had to be regularly adjusted for cooling, and excess cabin humidity, the rest of the flight was essentially flawless.

Glenn fired his retrorockets and descended back to Earth. He splashed down in the Atlantic, 40 miles downrange from the expected landing site. The USS Noa reached Friendship seventeen minutes later and hoisted it onto the ship. Glenn was supposed to exit the capsule from the top hatch, but instead decided to blow the side hatch instead. With a loud bang, the hatch blew open and Glenn emerged and jumped to the deck of the Noa. With a smile, his first words were: “It was hot in there.”

Astronaut John H. Glenn Jr. in his Mercury spacesuit

Astronaut John H. Glenn Jr. in his Mercury spacesuit. / Source: NASA

Glenn returned to a hero’s welcome and a ecstatic ticker-tape parade in New York City. Americans were energized with the progress in the race with the Soviets. And with John Glenn’s help, America — and mankind itself — took another step forward into the uncharted heavens above.

*This post was originally published February 20, 2011. Small updates have been made since then.


  1. In fact, it was solved during the next Mercury mission, Aurora 7, by Scott Carpenter. To test his theory, he banged on the side of the capsule and watched as they broke off of the exterior of the craft!
  2. And it provided a nice fireworks show for Glenn during re-entry. “My condition is good, but that was a real fireball, boy. I had great chunks of that retropack breaking off all the way through.”

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.


A Space Discovery Milestone, as Kepler Confirms 1000th Exoplanet

Kepler Mission Logo

Kepler Mission logo

It was just a few years ago, and I was excitedly reporting to you the first few exoplanets that the NASA Kepler space instrument was detecting and verifying. In fact, it was almost exactly 4 years ago today that I was telling you about confirmed exoplanet find number 9. That exoplanet, Kepler-10b, was the first confirmed find of a rocky world outside of our own solar system, and at the time was the smallest exoplanet ever discovered, at 1.4 times the diameter of Earth. Then, at the end of that year, I was telling you about the first exoplanet located by Kepler in the “habitable zone”. And in a short period of time, I was telling you about dozens of more exoplanets being confirmed, and mini-planetary systems, and exoplanets that orbit two different stars.

Well since then, Kepler’s been hard at work confirming exoplanet after exoplanet. Today, that count has reached a milestone:

NASA’s Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones

1,000 confirmed other worlds, orbiting other stars. Let me put that significance into perspective: if you were born in 1988 or earlier, you are the exoplanet generation, for 1988 was the year the first exoplanet was confirmed. I don’t know about you, but that fact really resonates with me. It proclaims to me that I live in a fantastic moment of human history. I was alive when Earthlings first knew for certain that there were planets outside of our own Solar system. And in less than three decades, we’ve found over 1,000 more. There are worlds out there, and we’re alive precisely at the time to first know it. And what’s even cooler, at least eight of those are roughly the same size as our own world and orbit their host star in what’s referred to as the habitable zone.

Artist's depiction of the 8 Earthlike planets confirmed by Kepler.

 

The Kepler mission will always be one of the most exciting for me personally, and is expected to confirm thousands more exoplanets over the coming years. What a time to be alive!

If this is as interesting to you as it is to me, here are a couple of other articles posted about Kepler discoveries that I think you’ll particularly appreciate:

Exciting Kepler News – Part 1: Mini-Planetary System

Exciting Kepler News – Part 2: New Circumbinary Planets

Kepler Finds First Earth-Sized Planets


NASA's State of the Solar System

Here’s an excellent infographic that details NASA’s current Solar System (and beyond!) spacecraft missions. It lists every craft NASA out exploring various bodies and their current status.

Click the image to make it a little bigger.

State of the Solar System infographic

State of the Solar System infographic

(Via)

 


New Horizons Awakens

If everything has gone according to its meticulous plan, by the time you are reading this NASA’s New Horizons spacecraft will have awoken from its electronic hibernation for the last time and begun its careful preparations to encounter Pluto in July of 2015.

Maybe I should back up for those that aren’t familiar with New Horizons, or just want a little recap:

New Horizons is the name of a NASA spacecraft and mission to complete a fly-by mission of Pluto and its moons, and then on to view other Kuiper-Belt objects. New Horizons will give us shiny new photos of our favorite dwarf planet and a wealth of other scientific data. It’s about time, too. I mean, just look at the current best image we have of what we–at least  used to–consider 1/9th of our solar system’s planetary awesomeness:

Pluto as imaged by Hubble in 2010.

Pluto as imaged by Hubble in 2010.

Yuck! And NASA was impressed enough to brag about these “most detailed and dramatic images ever taken of the distant dwarf planet“. I’m looking forward to which adjectives they’ll use when we get real images courtesy of New Horizons. But I digress.

On January 19, 2006, New Horizons lifted-off from its Cape Canaveral launchpad and screamed into the heavens. In fact, nothing before or since has left the Earth with such a sense of urgency. New Horizons holds the record for the fastest launch of any spacecraft. It left the Earth with a velocity of 36,373 miles per hour (58,356 kilometers/hour), fast enough to propel it not just out of the Earth’s orbit, but completely out of the solar system (referred to as a solar escape velocity).

Subsequently, New Horizons continued to voyage towards its 2015 encounter with Pluto. Along the way, it came within 1.4 million miles (2.3 million kilometers) of Jupiter, on February 28, 2007, and actually used its proximity to gain a gravity assist boost from the massive gas giant. This gave New Horizons a speed boost of about 9,000 miles per hour (14,000 kilometers/hour). Taking advantage of that graviational slingshot, the voyage to Pluto was shortened by three full years. Score! Free energy!

New Horizons zoomed along, passing Saturn’s orbit in June of 2008, Uranus’s in March of 2011, and then Neptune’s in August of this year.

Next up: Pluto.

Throughout its journey, New Horizons has gone through hibernation/wake cycles more than a dozen times, in fact, spending about 2/3 of its time in an electronic slumber. During hibernation, most of the craft’s systems are powered down or entered into an extremely low-functioning state. This “reduced wear and tear on the spacecraft’s electronics, it lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions”.  Today, however, New Horizons is waking for good.

Beginning in February, the main observation objectives begin. Around the beginning of May, New Horizons will be capturing images of Pluto exceeding the resolution that Hubble was able to produce. For the next two months, Pluto will become more accessible to all of the spacecraft’s instruments. The closest approach is projected for July 14, where New Horizons will be within 6,200 miles (10,000 kilometers) of Pluto. New Horizons’s Long Range Reconnaissance Imager (LORRI) is expected to capture images on the scale of 50 meters per pixel and accomplish a handful of other primary and secondary scientific objectives.

But wait, there’s more!

In addition to Pluto, New Horizons will be observing and recording images and data from Pluto’s known moons: Charon, Hydra, Nix, Styx, and Kerberos.

And that’s still not all. Remember how I mentioned that New Horizons is on a solar system escape trajectory? That means the craft is going to continue hurtling away from the Earth and Sun, away from Pluto, and out beyond the ends of our solar system and into intergalactic space. Included in the craft and mission design, is fly-by opportunities for one ore more Kuipier-Belt Objects (KBOs), the residents of the Kuiper Belt. If you’re not familiar with the Kuiper Belt, think asteroid belt except much larger but instead of rocky asteroids, these bodies consist more of frozen gases such as methane, ammonia, and water. (Some of the moons of our solar system are believed to be former residents of the Kuiper Belt, but that’s another story for another time.) The ability to complete this mission will depend on targetable candidates and remaining fuel supplies.

After all of this, New Horizons slips into the furthest reaches of the Sun’s influence, the fascinating realm known as the outer heliosphere, including the heliosheath and heliopause (again, another story/another time). If the craft is still alive at this point, New Horizons will continue the work of the Voyagers in mapping this interesting environment.

That’s it for today. Stay tuned for updates on this historical mission, and much, much more!