Solar System: Things To Know This Week

When you went into space for the first time, what was it like? Were you nervous?

This unprocessed image shows features in Saturn's atmosphere from closer than ever before. The view was captured by our Cassini spacecraft during its first Grand Finale dive between the planet and its rings on April 26, 2017.

As Cassini dove through the gap, it came within about 1,900 miles (3,000 kilometers) of Saturn's cloud tops (where the air pressure is 1 bar -- comparable to the atmospheric pressure of Earth at sea level) and within about 200 miles (300 kilometers) of the innermost visible edge of the rings.

See all the unprocessed images from Cassini: https://saturn.jpl.nasa.gov/galleries/raw-images/ 

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Happy Martian New Year!

For any planet, a year is the time it takes to make one orbit around the sun. Because Mars is farther away from the sun, it has to travel a greater distance than Earth. It takes Mars about twice as long as it does for Earth to make one circle around the sun…therefore, a year on Mars lasts twice as long.

On May 5, Mars passes solar longitude 0 as the sun crosses the equator on Mars. This is the vernal equinox and was chosen by planetary scientists as the start of a new year.

Mars has four seasons, roughly twice as long as those on Earth, but with more variation given Mars’ eccentric orbit and the fact its orbital speed varies more as a result.

Did you know that there’s a U.S. city named Mars? Mars, PA hosts an annual Mars New Year celebration and we’re participating in this two-day science, technology, engineering and math (STEM) event to inspire young people to pursue innovation and exploration.

More info on Mars, PA: http://www.marsnewyear.com/

Get updated images from the events in Mars, PA here: https://www.flickr.com/photos/nasahqphoto/sets/72157683457751005/

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Countdown to Launch of Landsat 9

We’re launching Landsat 9 — the ninth in a series of satellite missions from NASA and the U.S. Geological Survey (USGS) that have been collecting images of our planet for almost 50 years. Follow along as we count down to launch!

A normal launch countdown starts at 10, but for Landsat 9, we’re jumping in with L-9!

There are 9 million images in the USGS/NASA Landsat archive! They’re all available for free, for use by scientists, data managers, and anyone else who’s interested. You can even download them!

Landsat 9 won’t be orbiting alone. Working together, Landsat 9 and Landsat 8 will completely image Earth every 8 days! This helps us track changes on the planet’s surface as they happen in near-real-time.

Landsat sees all 7 continents! From Antarctic ice to growing cities to changing forests, Landsat measures land — and coastal regions — all around the globe.

Working in space is really hard. Landsat 6 never made it to orbit, an important reminder that failures can be opportunities to learn and grow. Shortly after the unsuccessful launch, engineers got to work on Landsat 7, which is still collecting data today — 22 years later.

We have 5 decades of Landsat observations, the longest continuous record of Earth’s land surfaces in existence! While building the original Landsat in the 1970s, it would have been hard to imagine that this mission would still be providing crucial data about our planet today.

For each color band collected, Landsat 9 will see 4 times the shades of light as the previous Landsat mission! With more than 16,000 different intensities detected, Landsat 9 will be able to see crucial details on our planet’s surface.

Our eyes detect 3 colors of light: red, green, and blue — and Landsat does too! But Landsat 9 also detects wavelengths that can be combined to measure things our eyes can’t, like crop stress, coral reef health, fires, and more.

There are 2 instruments on Landsat 9! The Operational Land Imager 2 collects light, and works kind of like our eyes — or cameras — to make data-rich images. The Thermal Infrared Sensor 2 measures temperature, helping monitor plant health, fires, and more.

The Landsat program is the result of 1 amazing partnership! For more than 50 years, we’ve worked with the U.S. Geological Survey to design, build, launch, and manage Landsat satellites.

Two agencies working together makes for the longest continuous record of Earth’s surfaces. Now, let’s launch this satellite!

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Solar System: Things to Know This Week

Like sailors of old, the Cassini mission team fondly thinks of the spacecraft as "she."  On April 22, she begins her Grand Finale, a spectacular end game—22 daring dives between the planet's atmosphere and innermost rings. Here are 10 things to know about her Grand Finale.

1. She's Broadcasting Live This Week

On Tuesday, April 4 at 3 p.m. EDT  (noon PDT), At Jet Propulsion Laboratory, the Cassini team host a news briefing to discuss the mission's Grand Finale.

Tune in Tuesday: youtube.com/nasajpl/live

2. She's Powered in Part By ... Titan

Cassini left Earth with less than 1/30th of the propellant needed to power all her adventures at Saturn. The navigation team used the gravity of Saturn's giant moon Titan to change course and extend the spacecraft's exploration of Saturn. Titan also provides the gravity assist to push Cassini into its final orbits.

More on Cassini's navigation: saturn.jpl.nasa.gov/mission/spacecraft/navigation/

3. She's a Robot

Cassini is an orbiter that was named for 18th century astronomer Giovanni Domenico Cassini. She was designed to be captured by Saturn's gravity and then explore it in detail with a suite of 12 powerful science instruments.

More on the Spacecraft: saturn.jpl.nasa.gov/mission/spacecraft/cassini-orbiter/

4. She Brought a Friend to Saturn

Cassini carried the European Space Agency's Huygens Probe, which in 2005 descended through Titan's thick, perpetual clouds and made the most distant landing to date in our solar system.

More on Huygens: saturn.jpl.nasa.gov/mission/spacecraft/huygens-probe/

5. She's a Great Photographer

Your mobile phone likely captures dozens of megapixels in images. Cassini, using 1990s technology closer to one megapixel cameras, has returned some of the most stunning images in the history of solar system exploration.

Cassini Hall of Fame Images: go.nasa.gov/2oec6H2 More on Cassini's Cameras: saturn.jpl.nasa.gov/imaging-science-subsystem/

6. She's an Inspiration

Those great images have inspired artist's and amateur image processors to create truly fantastic imagery inspired by the beauty of Saturn. Feeling inspired? There's still time to share your Cassini-inspired art with us.

Cassini Inspires Campaign: saturn.jpl.nasa.gov/mission/cassiniinspires/

7. She's Got a Long History

Two decades is a long time to live in the harsh environment of outer space (respect to the fast-approaching 40-year-old twin Voyager spacecraft). Launched in 1997, Cassini logged a lot of milestones over the years.

Explore the Cassini Timeline: saturn.jpl.nasa.gov/the-journey/timeline/

8. She Keeps a Diary

And, you can read it. Week after week going back to 1997, Cassini's adventures, discoveries and status have been chronicled in the mission's weekly significant events report.

Read It: https://saturn.jpl.nasa.gov/news/?topic=121

9. She's Got a Fancy New App

Cassini was the prototype for NASA's Eyes on the Solar System 3-D visualization software, so it's fitting the latest Cassini module in the free, downloadable software is the most detailed, elaborate visualization of any mission to date.

Fly the Mission - Start to Finish: http://eyes.nasa.gov/cassini

10. She's Going Out in a Blaze of Glory

In addition to all the new information from 22 orbits in unexplored space, Cassini's engineers reprogrammed the spacecraft to send back details about Saturn's atmosphere to the very last second before the giant planet swallows her up on Sept. 15, 2017.

More on the Grand Finale: saturn.jpl.nasa.gov/grandfinale

Discover more lists of 10 things to know about our solar system HERE.

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How Do We Learn About a Planet’s Atmosphere?

The first confirmation of a planet orbiting a star outside our solar system happened in 1995. We now know that these worlds – also known as exoplanets – are abundant. So far, we’ve confirmed more than 4000. Even though these planets are far, far away, we can still study them using ground-based and space-based telescopes.

Our upcoming James Webb Space Telescope will study the atmospheres of the worlds in our solar system and those of exoplanets far beyond. Could any of these places support life? What Webb finds out about the chemical elements in these exoplanet atmospheres might help us learn the answer.

How do we know what’s in the atmosphere of an exoplanet?

Most known exoplanets have been discovered because they partially block the light of their suns. This celestial photo-bombing is called a transit.

During a transit, some of the star's light travels through the planet's atmosphere and gets absorbed.

The light that survives carries information about the planet across light-years of space, where it reaches our telescopes.

(However, the planet is VERY small relative to the star, and VERY far away, so it is still very difficult to detect, which is why we need a BIG telescope to be sure to capture this tiny bit of light.)

So how do we use a telescope to read light?

Stars emit light at many wavelengths. Like a prism making a rainbow, we can separate light into its separate wavelengths. This is called a spectrum. Learn more about how telescopes break down light here. 

Visible light appears to our eyes as the colors of the rainbow, but beyond visible light there are many wavelengths we cannot see.

Now back to the transiting planet...

As light is traveling through the planet's atmosphere, some wavelengths get absorbed.

Which wavelengths get absorbed depends on which molecules are in the planet's atmosphere. For example, carbon monoxide molecules will capture different wavelengths than water vapor molecules.

So, when we look at that planet in front of the star, some of the wavelengths of the starlight will be missing, depending on which molecules are in the atmosphere of the planet.

Learning about the atmospheres of other worlds is how we identify those that could potentially support life...

...bringing us another step closer to answering one of humanity's oldest questions: Are we alone?

Watch the full video where this method of hunting for distant planets is explained:

To learn more about NASA’s James Webb Space Telescope, visit the website, or follow the mission on Facebook, Twitter and Instagram. 

Text and graphics credit Space Telescope Science Institute

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Are we alone in the universe?

There’s never been a better time to ponder this age-old question. We now know of thousands of exoplanets – planets that orbit stars elsewhere in the universe.

So just how many of these planets could support life?

Scientists from a variety of fields — including astrophysics, Earth science, heliophysics and planetary science — are working on this question. Here are a few of the strategies they’re using to learn more about the habitability of exoplanets.

Squinting at Earth

Even our best telescopic images of exoplanets are still only a few pixels in size. Just how much information can we extract from such limited data? That’s what Earth scientists have been trying to figure out.

One group of scientists has been taking high-resolution images of Earth from our Earth Polychromatic Imaging Camera and ‘degrading’ them in order to match the resolution of our pixelated exoplanet images. From there, they set about a grand process of reverse-engineering: They try to extract as much accurate information as they can from what seems — at first glance — to be a fairly uninformative image.

Credits: NOAA/NASA/DSCOVR

So far, by looking at how Earth’s brightness changes when land versus water is in view, scientists have been able to reverse-engineer Earth's albedo (the proportion of solar radiation it reflects), its obliquity (the tilt of its axis relative to its orbital plane), its rate of rotation, and even differences between the seasons. All of these factors could potentially influence a planet’s ability to support life.

Avoiding the “Venus Zone”

In life as in science, even bad examples can be instructive. When it comes to habitability, Venus is a bad example indeed: With an average surface temperature of 850 degrees Fahrenheit, an atmosphere filled with sulfuric acid, and surface pressure 90 times stronger than Earth’s, Venus is far from friendly to life as we know it.

The surface of Venus, imaged by Soviet spacecraft Venera 13 in March 1982

Since Earth and Venus are so close in size and yet so different in habitability, scientists are studying the signatures that distinguish Earth from Venus as a tool for differentiating habitable planets from their unfriendly look-alikes.

Using data from our Kepler Space Telescope, scientists are working to define the “Venus Zone,” an area where planetary insolation – the amount of light a given planet receives from its host star -- plays a key role in atmospheric erosion and greenhouse gas cycles.

Planets that appear similar to Earth, but are in the Venus Zone of their star, are, we think, unlikely to be able to support life.

Modeling Star-Planet Interactions

When you don’t know one variable in an equation, it can help to plug in a reasonable guess and see how things work out. Scientists used this process to study Proxima b, our closest exoplanet neighbor. We don’t yet know whether Proxima b, which orbits the red dwarf star Proxima Centauri four light-years away, has an atmosphere or a magnetic field like Earth’s. However, we can estimate what would happen if it did.

The scientists started by calculating the radiation emitted by Proxima Centauri based on observations from our Chandra X-ray Observatory. Given that amount of radiation, they estimated how much atmosphere Proxima b would be likely to lose due to ionospheric escape — a process in which the constant outpouring of charged stellar material strips away atmospheric gases.

With the extreme conditions likely to exist at Proxima b, the planet could lose the equivalent of Earth’s entire atmosphere in 100 million years — just a fraction of Proxima b’s 4-billion-year lifetime. Even in the best-case scenario, that much atmospheric mass escapes over 2 billion years. In other words, even if Proxima b did at one point have an atmosphere like Earth, it would likely be long gone by now.

Imagining Mars with a Different Star

We think Mars was once habitable, supporting water and an atmosphere like Earth’s. But over time, it gradually lost its atmosphere – in part because Mars, unlike Earth, doesn’t have a protective magnetic field, so Mars is exposed to much harsher radiation from the Sun's solar wind.

But as another rocky planet at the edge of our solar system’s habitable zone, Mars provides a useful model for a potentially habitable planet. Data from our Mars Atmosphere and Volatile Evolution, or MAVEN, mission is helping scientists answer the question: How would Mars have evolved if it were orbiting a different kind of star?

Scientists used computer simulations with data from MAVEN to model a Mars-like planet orbiting a hypothetical M-type red dwarf star. The habitable zone of such a star is much closer than the one around our Sun.

Being in the habitable zone that much closer to a star has repercussions. In this imaginary situation, the planet would receive about 5 to 10 times more ultraviolet radiation than the real Mars does, speeding up atmospheric escape to much higher rates and shortening the habitable period for the planet by a factor of about 5 to 20.

These results make clear just how delicate a balance needs to exist for life to flourish. But each of these methods provides a valuable new tool in the multi-faceted search for exoplanet life.  Armed with these tools, and bringing to bear a diversity of scientific perspectives, we are better positioned than ever to ask: are we alone?

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Eight Things to Know About Our Flying Observatory

Our flying observatory, called SOFIA, is the world’s largest airborne observatory. It is a partnership with the German Aerospace Center (DLR). SOFIA studies the life cycle of stars, planets (including Pluto’s atmosphere), how interstellar dust can contribute to planet formation, analyzes the area around black holes, and identifies complex molecules in space.

1. A Telescope in an Airplane

SOFIA stands for the Stratospheric Observatory for Infrared Astronomy. It is a Boeing 747SP aircraft that carries a 100-inch telescope to observe the universe while flying between 38,000 and 45,000 feet – the layer of Earth’s atmosphere called the stratosphere.

2. The Short Aircraft Means Long Flights

SP stands for “special performance.” The plane is 47 feet shorter than a standard 747, so it’s lighter and can fly greater distances.  Each observing flight lasts 10-12 hours.

3. It Flies with A Hole in the Side of the Plane…

The telescope is behind a door that opens when SOFIA reaches altitude so astronomers on board can study the universe. The kind of light SOFIA observes, infrared, is blocked by almost all materials, so engineers designed the side of the aircraft to direct air up-and-over the open cavity, ensuring a smooth flight.

4. …But the Cabin is Pressurized!

A wall, called a pressure bulkhead, was added between the telescope and the cabin so the team inside the aircraft stays comfortable and safe. Each flight has pilots, telescope operators, scientists, flight planners and mission crew aboard.

5. This Telescope Has to Fly

Water vapor in Earth’s atmosphere blocks infrared light from reaching the ground. Flying at more than 39,000 feet puts SOFIA above more than 99% of this vapor, allowing astronomers to study infrared light coming from space. The airborne observatory can carry heavier, more powerful instruments than space-based observatories because it is not limited by launch weight restrictions and solar power.

6. Studying the Invisible Universe

Humans cannot see what is beyond the rainbow of visible light. However, many interesting astronomical processes happen in the clouds of dust and gas that often surround the objects SOFIA studies, like newly forming stars. Infrared light can pass through these clouds, allowing astronomers to study what is happening inside these areas.

7. The German Telescope

The telescope was built our partner, the German Aerospace Center, DLR. It is made of a glass-ceramic material called Zerodur that does not change shape when exposed to extremely cold temperatures. The telescope has a honeycomb design, which reduces the weight by 80%, from 8,700 lb to 1,764 lb. (Note that the honeycomb design was only visible before the reflective aluminum coating was applied to the mirror’s surface).

8. ZigZag Flights with a Purpose

The telescope can move up and down, between 20-60 degrees above the horizon. But it can only move significantly left and right by turning the whole aircraft. Each new direction of the flight means astronomers are studying a new celestial object. SOFIA’s flight planners carefully map where the plane needs to fly to best observe each object planned for that night.

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Solar System: Things To Know This Week

Weather permitting, you can observe the Moon most nights, unless it's a new moon, when the lighted side of the Moon faces away from Earth. The Moon is by far the brightest object in the night sky and there's plenty to see. But this week is special...

...October 28 is International Observe the Moon Night (also known as InOMN).

Here's all you need to know to join in and celebrate:

1. One Planet. One Moon. One Night.

Everyone on Earth is invited to join the celebration by hosting or attending an InOMN event and uniting on one day each year to look at and learn about the Moon together.

2. What's Up?

October's night skies are full of sights, from the first quarter Moon on InOMN to Saturn making a cameo appearance above the Moon October 23 and 24. Watch our What's Up video for details.

3. Be Social

Hundreds of events are planned around the globe. Click the top link on this page for a handy map. You can also register your own event.

4. Don't Just Stand There

Here are some activities for enhanced Moon watching.

5. Impress Your Friends with Moon Knowledge

Download InOMN flyers and handouts, Moon maps and even some pre-made presentations. There's even a certificate to mark your participation.

6. Guide to the Face of the Moon

Almost dead center on the Earth-facing side of the Moon is the Surveyor 6 robotic spacecraft impact side. Apollo 12 and 14 are a bit to the left. And Apollo 11 - the first steps on the moon - are to the right. This retro graphic tells the whole story.

7. Moon Shots

NASA photographers have done some exceptional work capturing views of the Moon from Earth. Here are a few galleries:

You can't have a solar eclipse without the Moon.

The 2016 "Supermoon" was pretty spectacular.

The Moon gets eclipsed, too.

That IS a Moon - AND the International Space Station.

The Moon is always a great photo subject.

Some spooky shots of the 2014 "Supermoon."

And 2013.

Tips from a NASA pro for photographing the Moon.

8. Walking on the Moon

Twelve human beings walked on the face of the Moon. Here are some of the best shots from the Apollo program.

9. Moon Watch

Our Lunar Reconnaissance Orbiter is up there right now, mapping the moon and capturing some spectacular high-resolution shots.

10. Keep Exploring

Make our Moon portal your base for further lunar exploration.

Check out the full version of ‘Ten Things to Know This Week’ HERE.

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4 people are living in an isolated habitat for 30 days. Why? Science!

This 30 day mission will help our researchers learn how isolation and close quarters affect individual and group behavior. This study at our Johnson Space Center prepares us for long duration space missions, like a trip to an asteroid or even to Mars.

The Human Research Exploration Analog (HERA) that the crew members will be living in is one compact, science-making house. But unlike in a normal house, these inhabitants won't go outside for 30 days. Their communication with the rest of planet Earth will also be very limited, and they won’t have any access to internet. So no checking social media kids!

The only people they will talk with regularly are mission control and each other.

The crew member selection process is based on a number of criteria, including the same criteria for astronaut selection.

What will they be doing?

Because this mission simulates a 715-day journey to a Near-Earth asteroid, the four crew members will complete activities similar to what would happen during an outbound transit, on location at the asteroid, and the return transit phases of a mission (just in a bit of an accelerated timeframe). This simulation means that even when communicating with mission control, there will be a delay on all communications ranging from 1 to 10 minutes each way. The crew will also perform virtual spacewalk missions once they reach their destination, where they will inspect the asteroid and collect samples from it. 

A few other details:

The crew follows a timeline that is similar to one used for the ISS crew.

They work 16 hours a day, Monday through Friday. This includes time for daily planning, conferences, meals and exercises.  

They will be growing and taking care of plants and brine shrimp, which they will analyze and document.

But beware! While we do all we can to avoid crises during missions, crews need to be able to respond in the event of an emergency. The HERA crew will conduct a couple of emergency scenario simulations, including one that will require them to maneuver through a debris field during the Earth-bound phase of the mission. 

Throughout the mission, researchers will gather information about cohabitation, teamwork, team cohesion, mood, performance and overall well-being. The crew members will be tracked by numerous devices that each capture different types of data.

Past HERA crew members wore a sensor that recorded heart rate, distance, motion and sound intensity. When crew members were working together, the sensor would also record their proximity as well, helping investigators learn about team cohesion.

Researchers also learned about how crew members react to stress by recording and analyzing verbal interactions and by analyzing “markers” in blood and saliva samples.

In total, this mission will include 19 individual investigations across key human research elements. From psychological to physiological experiments, the crew members will help prepare us for future missions.

UPDATE:

Mission success! After a simulated mission to an asteroid, the crew “splashed down” around 10:30 p.m. EST on Wednesday, Feb. 24 and exited the habitat for the first time in 30 days.

Want a full, 360 degree look at HERA? Check out and explore the inside of the habitat.

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