What Have We Learned About Pluto?

This month (March 2016), in the journal Science, New Horizons scientists have authored the first comprehensive set of papers describing results from last summer’s Pluto system flyby. These detailed papers completely transform our view of Pluto and reveal the former “astronomer’s planet” to be a real world with diverse and active geology, exotic surface chemistry, a complex atmosphere, puzzling interaction with the sun and an intriguing system of small moons.

Here’s a breakdown of what we’ve learned about Pluto:

1. Pluto has been geologically active throughout the past 4 billion years. The age-dating of Pluto’s surface through crater counts has revealed that Pluto has been geologically active throughout the past 4 billion years. Further, the surface of Pluto’s informally-named Sputnik Planum, a massive ice plain larger than Texas, is devoid of any detectable craters and estimated to be geologically young – no more than 10 million years old.

2. Pluto’s moon Charon has been discovered to have an ancient surface. As an example, the great expanse of smooth plains on Charon is likely a vast cryovolcanic flow or flows that erupted onto Charon’s surface about 4 billion years ago. These flows are likely related to the freezing of an internal ocean that globally ruptured Charon’s crust.

3. Pluto’s surface has many types of terrain. The distribution of compositional units on Pluto’s surface – from nitrogen-rich, to methane-rich, to water-rich – has been found to be surprisingly complex, creating puzzles for understanding Pluto’s climate and geologic history. The variations in surface composition on Pluto are unprecedented elsewhere in the outer solar system.

4. Pluto’s atmosphere is colder than we thought. Pluto’s upper atmospheric temperature has been found to be much colder (by about 70 degrees Fahrenheit) than had been thought from Earth-based studies, with important implications for its atmospheric escape rate. Why the atmosphere is colder is a mystery.

5. We know what Pluto’s atmosphere is made of. The New Horizon spacecraft made observations of sunlight passing through Pluto’s atmosphere. We see absorption features that indicate an atmosphere made up of nitrogen (like Earth’s) with methane, acetylene and ethylene as minor constituents.

6. We might have an idea for how Pluto’s haze formed. For first time, a plausible mechanism for forming Pluto’s atmospheric haze layers has been found. This mechanism involves the concentration of haze particles by atmospheric buoyancy waves, created by winds blowing over Pluto’s mountainous topography. Pluto’s haze extends hundreds of kilometers into space, and embedded within it are over 20 very thin, but far brighter, layers.

7. There isn’t much dust around Pluto. Before the flyby, there was concern that a small piece of debris (even the size of a grain of sand) could cause great damage to (or even destroy) the spacecraft. But the Venetia Burney Student Dust Counter (an instrument on the New Horizons spacecraft) only counted a single dust particle within five days of the flyby. This is similar to the density of dust particles in free space in the outer solar system – about 6 particles per cubic mile – showing that the region around Pluto is, in fact, not filled with debris.

8. Pluto’s atmosphere is smaller than we expected. The uppermost region of Pluto’s atmosphere is slowly escaping to space. The hotter the upper atmosphere, the more rapid the gasses escape. The lower the planet’s mass, the lower the gravity, and the faster the atmospheric loss. As molecules escape, they are ionized by solar ultraviolet light. Once ionized, the charged molecules are carried away by the solar wind. As more Pluto-genic material is picked up by the solar wind, the more the solar wind is slowed down and deflected around Pluto. So - the net result is a region (the interaction region), which is like a blunt cone pointed toward the sun, where the escaping ionized gasses interact with the solar wind. The cone extends to a distance about 6 Pluto radii from Pluto toward the sun, but extend behind Pluto at least 400 Pluto radii behind Pluto - like a wake behind the dwarf planet.

9. Pluto’s moons are brighter than we thought. The high albedos (reflectiveness) of Pluto’s small satellites (moons) – about 50 to 80 percent – are entirely different from the much lower reflectiveness of the small bodies in the general Kuiper Belt population, which range from about 5 to 20 percent. This difference lends further support to the idea that these moons were not captured from the general Kuiper Belt population, but instead formed by the collection of material produced in the aftermath of the giant collision that created the entire Pluto satellite system.

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It’s a U.S. Record! Cumulative Days in Space: 383

Today, Astronaut Scott Kelly has broken the record for longest time spent in space by a U.S. astronaut! Over the course of his four missions, Kelly has spent 383 cumulative days in space. This record was previously held by Astronaut Mike Fincke, with 382 days in space over three flights. Here are some more fun facts about this milestone:

4: The number of humans that have spent a year or more in orbit on a single mission

215 Days: The record currently held by Mike Lopez-Alegria for most time on a single spaceflight by U.S. astronaut. On Oct. 29, Kelly will break this record

377 Days: The current record for most days in space by a U.S. female astronaut, held by Peggy Whitson

879 Days: The record for most cumulative days in space by a human, currently held by Russian cosmonaut Gennady Padalka

Why Spend a Year in Space?

Kelly’s One-Year Mission is an important stepping stone on our journey to Mars and other deep space destinations. These investigations are expected to yield beneficial knowledge on the medical, psychological and biomedical challenges faced by astronauts during long-duration spaceflight.

Kelly is also involved in the Twins Study, which consists of ten separate investigations that are being conducted with his twin brother, who is on Earth. Since we are able to study two individuals who have the same genetics, but are in different environments for one year, we can gain a broader insight into the subtle effects and changes that may occur in spaceflight.

For regular updates on Kelly’s one-year mission aboard the space station, follow him on social media: Facebook, Twitter, Instagram.

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9 years ago

NASA Gemini Mission Spacewalk. Famous shot. Note the hand held maneuvering gun

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7 years ago

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Incoming! We’ve Got Science from Jupiter!

Our Juno spacecraft has just released some exciting new science from its first close flyby of Jupiter!

In case you don’t know, the Juno spacecraft entered orbit around the gas giant on July 4, 2016…about a year ago. Since then, it has been collecting data and images from this unique vantage point.

Juno is in a polar orbit around Jupiter, which means that the majority of each orbit is spent well away from the gas giant. But once every 53 days its trajectory approaches Jupiter from above its north pole, where it begins a close two-hour transit flying north to south with its eight science instruments collecting data and its JunoCam camera snapping pictures.

Space Fact: The download of six megabytes of data collected during the two-hour transit can take one-and-a-half days!

Juno and her cloud-piercing science instruments are helping us get a better understanding of the processes happening on Jupiter. These new results portray the planet as a complex, gigantic, turbulent world that we still need to study and unravel its mysteries.

So what did this first science flyby tell us? Let’s break it down…

1. Tumultuous Cyclones

Juno’s imager, JunoCam, has showed us that both of Jupiter’s poles are covered in tumultuous cyclones and anticyclone storms, densely clustered and rubbing together. Some of these storms as large as Earth!

These storms are still puzzling. We’re still not exactly sure how they formed or how they interact with each other. Future close flybys will help us better understand these mysterious cyclones.

Seen above, waves of clouds (at 37.8 degrees latitude) dominate this three-dimensional Jovian cloudscape. JunoCam obtained this enhanced-color picture on May 19, 2017, at 5:50 UTC from an altitude of 5,500 miles (8,900 kilometers). Details as small as 4 miles (6 kilometers) across can be identified in this image.

An even closer view of the same image shows small bright high clouds that are about 16 miles (25 kilometers) across and in some areas appear to form “squall lines” (a narrow band of high winds and storms associated with a cold front). On Jupiter, clouds this high are almost certainly comprised of water and/or ammonia ice.

2. Jupiter’s Atmosphere

Juno’s Microwave Radiometer is an instrument that samples the thermal microwave radiation from Jupiter’s atmosphere from the tops of the ammonia clouds to deep within its atmosphere.

Data from this instrument suggest that the ammonia is quite variable and continues to increase as far down as we can see with MWR, which is a few hundred kilometers. In the cut-out image below, orange signifies high ammonia abundance and blue signifies low ammonia abundance. Jupiter appears to have a band around its equator high in ammonia abundance, with a column shown in orange.

Why does this ammonia matter? Well, ammonia is a good tracer of other relatively rare gases and fluids in the atmosphere…like water. Understanding the relative abundances of these materials helps us have a better idea of how and when Jupiter formed in the early solar system.

This instrument has also given us more information about Jupiter’s iconic belts and zones. Data suggest that the belt near Jupiter’s equator penetrates all the way down, while the belts and zones at other latitudes seem to evolve to other structures.

3. Stronger-Than-Expected Magnetic Field

Prior to Juno, it was known that Jupiter had the most intense magnetic field in the solar system…but measurements from Juno’s magnetometer investigation (MAG) indicate that the gas giant’s magnetic field is even stronger than models expected, and more irregular in shape.

At 7.766 Gauss, it is about 10 times stronger than the strongest magnetic field found on Earth! What is Gauss? Magnetic field strengths are measured in units called Gauss or Teslas. A magnetic field with a strength of 10,000 Gauss also has a strength of 1 Tesla.

Juno is giving us a unique view of the magnetic field close to Jupiter that we’ve never had before. For example, data from the spacecraft (displayed in the graphic above) suggests that the planet’s magnetic field is “lumpy”, meaning its stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action (where the motion of electrically conducting fluid creates a self-sustaining magnetic field) closer to the surface, above the layer of metallic hydrogen. Juno’s orbital track is illustrated with the black curve.

4. Sounds of Jupiter

Juno also observed plasma wave signals from Jupiter’s ionosphere. This movie shows results from Juno’s radio wave detector that were recorded while it passed close to Jupiter. Waves in the plasma (the charged gas) in the upper atmosphere of Jupiter have different frequencies that depend on the types of ions present, and their densities.

Mapping out these ions in the jovian system helps us understand how the upper atmosphere works including the aurora. Beyond the visual representation of the data, the data have been made into sounds where the frequencies and playback speed have been shifted to be audible to human ears.

5. Jovian “Southern Lights”

The complexity and richness of Jupiter’s “southern lights” (also known as auroras) are on display in this animation of false-color maps from our Juno spacecraft. Auroras result when energetic electrons from the magnetosphere crash into the molecular hydrogen in the Jovian upper atmosphere. The data for this animation were obtained by Juno’s Ultraviolet Spectrograph.

During Juno’s next flyby on July 11, the spacecraft will fly directly over one of the most iconic features in the entire solar system – one that every school kid knows – Jupiter’s Great Red Spot! If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno.

Stay updated on all things Juno and Jupiter by following along on social media: Twitter | Facebook | YouTube | Tumblr

Learn more about the Juno spacecraft and its mission at Jupiter HERE.

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8 years ago

(via https://www.youtube.com/watch?v=HU5kpIQ09Iw)

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8 years ago

Spacewalk Friday: Installing a New "Parking Spot" on Station

This Friday, Aug. 19, two U.S. astronauts will install a new gateway for American commercial crew spacecraft at the International Space Station.

Commercial crew flights from Florida’s Space Coast to the International Space Station will restore America’s human spaceflight launch capability and increase the time U.S. crews can dedicate to scientific research.

The adapter being installed (imaged below) was launched on a SpaceX Dragon cargo spacecraft and arrived on orbit July 20. NASA astronauts Jeff Williams and Kate Rubins will perform the spacewalk to install the equipment this Friday, Aug. 19. This will be the fourth spacewalk in Williams’ career and the first for Rubins.

Four previous spacewalks…like the one below…helped set the stage for installation of this docking adapter. During those previous spacewalks, other crew members laid hundreds of feet of power and data cables outside the space station.

On Wednesday, the robotics team using the Canadarm2 and its attached “Dextre” manipulator, will reach into the SpaceX Dragon trunk and pull out the docking adapter and position it for Friday’s spacewalk activities.

The morning of the spacewalk, while the astronauts are getting suited up, the robotic arm will position the docking adaptor near the port so that it will be ready for installation.

The two astronauts will venture outside the space station to install the first International Docking Adapter (IDA). This new adapter port will provide a parking space for U.S. Commercial Crew vehicles.

Watch LIVE!

Coverage of the spacewalk begins at 6:30 a.m. EDT on Friday, Aug. 19; with the spacewalk scheduled to begin at 8:05 a.m. EDT. Stream live online HERE.

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9 years ago

M8 M16 M17 And M20 Gems Of The Summer Milky Way by Martin Campbell on Flickr.

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7 years ago

2017 - Johnson Space Center Year in Review

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7 years ago

NASA BEST engineering design challenges offer a transdisciplinary STEM approach that's fun and engaging! #nasamei2017 (at NASA - Johnson Space Center in Houston, TX)