Stormy Seas In Sagittarius

The Space Shuttle Challenger at a foggy Cape Canaveral, 1984.

(NASA/Department of Defense)

Young Stellar Grouping in Cygnus X

Cygnus X hosts many young stellar groupings. The combined outflows and ultraviolet radiation from the region’s numerous massive stars have heated and pushed gas away from the clusters, producing cavities of hot, lower-density gas.

In this 8-micron infrared image, ridges of denser gas mark the boundaries of the cavities. Bright spots within these ridges show where stars are forming today.

Credit: NASA/IPAC/MSX

Chasing the Shadow of Neptune’s Moon Triton

Our Flying Observatory

Our flying observatory, called SOFIA, carries a 100-inch telescope inside a Boeing 747SP aircraft. Scientists onboard study the life cycle of stars, planets (including the atmosphere of Mars and Jupiter), nearby planetary systems, galaxies, black holes and complex molecules in space.

AND in just a few days SOFIA is going on a special flight to chase the shadow of Neptune’s moon Triton as it crosses Earth’s surface!

In case you’re wondering, SOFIA stands for: Stratospheric Observatory for Infrared Astronomy.

Triton

Triton is 1,680 miles (2,700 km) across, making it the largest of the 13 moons orbiting Neptune. Unlike most large moons in our solar system, Triton orbits in the opposite direction of Neptune, called a retrograde orbit. This backward orbit leads scientists to believe that Triton formed in an area past Neptune, called the Kuiper Belt, and was pulled into its orbit around Neptune by gravity. 

The Voyager 2 spacecraft flew past Neptune and Triton in 1989 and found that Triton’s atmosphere is made up of mostly nitrogen…but it has not been studied in nearly 16 years!

Occultations are Eclipse-Like Events

An occultation occurs when an object, like a planet or a moon, passes in front of a star and completely blocks the light from that star. As the object blocks the star’s light, it casts a faint shadow on Earth’s surface. 

But unlike an eclipse, these shadows are not usually visible to the naked eye because the star and object are much smaller and not nearly as bright as our sun. Telescopes with special instruments can actually see these shadows and study the star’s light as it passes near and around the object – if they can be in the right place on Earth to catch the shadow.

Chasing Shadows

Scientists have been making advanced observations of Triton and a background star. They’ve calculated exactly where Triton’s faint shadow will fall on Earth! Our SOFIA team has designed a flight path that will put SOFIA (the telescope and aircraft) exactly in the center of the shadow at the precise moment that Triton and the star will align. 

This is no easy feat because the shadow is moving at more than 53,000 mph while SOFIA flies at Mach 0.85 (652 mph), so we only have about two minutes to catch the shadow!! But our SOFIA team has previously harnessed the aircraft’s mobility to study Pluto from inside the center of its occultation shadow, and is ready to do it again to study Triton!

What We Learn From Inside the Shadow

From inside the shadow, our team on SOFIA will study the star’s light as it passes around and through Triton’s atmosphere. This allows us to learn more about Triton’s atmosphere, including its temperature, pressure, density and composition! 

Our team will use this information to examine if Triton’s atmosphere has changed since our Voyager 2 spacecraft flew past it in 1989. That’s a lot of information from a bit of light inside a shadow! Similar observations of Uranus in 1977, from our previous flying observatory, led to the discovery of rings around that planet!

International Ground-Based Support

Ground-based telescopes across the United States and Europe – from Scotland to the Canary Islands – will also be studying Triton’s occultation. Even though most of these telescopes will not be in the center of the shadow, the simultaneous observations, from different locations on Earth, will give us information about how Triton’s atmosphere varies across its latitudes. 

This data from across the Earth and from onboard SOFIA will help researchers understand how Triton’s atmosphere is distorted at different locations by its high winds and its strong tides!

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Martian North Pole

ESA / G. Neukum (Freie Universitaet, Berlin) / Bill Dunford

Ask Ethan: Why don’t we build a telescope without mirrors or lenses?

“Why do we need a lens and a mirror to make a telescope now that we have CCD sensors? Instead of having a 10m mirror and lens that focus the light on a small sensor, why not have a 10m sensor instead?”

Every time you shine light through a lens or reflect it off of a mirror, no matter how good it is, a portion of your light gets lost. Today’s largest, most powerful telescopes don’t even simply have a primary mirror, but secondary, tertiary, even quaternary or higher mirrors, and each of those reflections means less light to derive your data from. As CCDs and other digital devices are far more efficient than anything else, why couldn’t we simply replace the primary mirror with a CCD array to collect and measure the light? It seems like a brilliant idea on the surface, and it would, in fact, gather significantly more light over the same collecting area. True, CCDs are more expensive, and there are technical challenges as far as applying filters and aligning the array properly. But there’s a fundamental problem if you don’t use a mirror or lens at all that may turn out to be a dealbreaker: CCDs without lenses or mirrors are incapable of measuring the direction light is coming from. A star or galaxy would appear equally on all portions of your CCD array at once, giving you just a bright, white-light image on every single CCD pixel.

It’s a remarkable idea, but there’s a good physical reason why it won’t pan out. For the foreseeable future, we still need optics to make a telescope! Find out why on this week’s Ask Ethan.

Solar System: 10 Things to Know This Week

Even the most ambitious plans start with a drawing. Visualizing a distant destination or an ambitious dream is the first step to getting there. For decades, artists working on NASA projects have produced beautiful images that stimulated the imaginations of the people working to make them a reality. 

Some of them offered visualizations of spacecraft that had not yet been built; others imagined what it might look like to stand on planets that had not yet been explored. This week, we look at 10 pieces of conceptual art for our missions before they were launched–along with actual photos taken when those missions arrived at their destinations.

1. Apollo at the Moon

In 1968, an artist with our contractor North American Rockwell illustrated a phase of the Apollo lunar missions, showing the Command and Service Modules over the surface of the Moon. In 1971, an astronaut aboard the Lunar Module during Apollo 15 captured a similar scene in person with a camera.

2. Ready for Landing

This artist’s concept depicts an Apollo Lunar Module firing its descent engine above the lunar surface. At right, a photo from Apollo 12 in 1969 showing the Lunar Module Intrepid, taken by Command Module Pilot Richard Gordon.

3. Man and Machine on the Moon

Carlos Lopez, an artist with Hughes Aircraft Company, created a preview of a Surveyor spacecraft landing for our Jet Propulsion Laboratory in the early 1960s. The robotic Surveyor missions soft landed on the Moon, collecting data and images of the surface in order to ensure a safe arrival for Apollo astronauts a few years later. In the image at right, Apollo 12 astronaut Alan Bean examines the Surveyor 3 spacecraft during his second excursion on the Moon in November 1969.

4. O Pioneer!

In missions that lived up to their names, we sent the Pioneer 10 and 11 spacecraft to perform the first up-close exploration of the outer solar system. At left, an artist’s imagining of Pioneer passing Jupiter. At right, Pioneer 11’s real view of the king of planets taken in 1974.

5. The Grand Tour

An even more ambitious pair of robotic deep space adventurers followed the Pioneers. Voyager 1 and 2 both visited Jupiter and Saturn. Voyager 2 went on to Uranus and Neptune. Even the most visionary artists couldn’t imagine the exotic and beautiful vistas that the Voyager spacecraft witnessed. These images were taken between 1979 and 1989.

6. Journey to a Giant

Our Cassini spacecraft carried a passenger to the Saturn system: the European Space Agency’s Huygens probe. Huygens was designed to land on Saturn’s planet-sized moon Titan. At left is an artist’s view of Cassini sending the Huygens probe on its way toward Titan, and at right are some actual images of the giant moon from Cassini’s cameras.

7. Titan Unveiled

On Jan. 14, 2005, the Huygens probe descended through Titan’s thick haze and revealed what Titan’s surface looks like for the first time in history. Before the landing, an artist imagined the landscape (left). During the descent, Huygens’ imagers captured the actual view at four different altitudes (center)—look for the channels formed by rivers of liquid hyrdocarbons. Finally, the probe came to rest on a pebble-strewn plain (right).

8. Hazy Skies over Pluto

David Seal rendered this imaginary view from the surface of Pluto, and in the sky above, an early version of the spacecraft that came to be known as our New Horizons. At the time, Pluto was already suspected of having a thin atmosphere. That turned out be true, as seen in this dramatic backlit view of Pluto’s hazy, mountainous horizon captured by one of New Horizons’ cameras in 2015.

9. Dreams on Mars, Wheels on Mars

Long before it landed in Gale Crater, our Curiosity rover was the subject of several artistic imaginings during the years the mission was in development. Now that Curiosity is actually rolling through the Martian desert, it occasionally stops to take a self-portrait with the camera at the end of its robotic arm, which it uses like a selfie stick.

10. The World, Ceres

No one knew exactly what the dwarf planet Ceres, the largest body in the asteroid belt, looked like until our Dawn mission got there. Dawn saw a heavily cratered world—with a few surprises, such as the famous bright spots in Occator crater.

There’s more to come. Today we have carefully created artist impressions of several unexplored destinations in the solar system, including the asteroids Psyche and Bennu, and an object one billion miles past Pluto that’s now called 2014 MU69. 

You can help nickname this object (or objects—there may be two) by submitting your names by Dec. 1. Our New Horizons spacecraft will fly past MU69 on New Year’s Day 2019.

Soon, we’ll once again see how nature compares to our imaginations. It’s almost always stranger and more beautiful than we thought.

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A Hitchhiker’s Ride to Space

This month, we are set to launch the latest weather satellite from the National Oceanic and Atmospheric Administration (NOAA). The Joint Polar Satellite System-1, or JPSS-1, satellite will provide essential data for timely and accurate weather forecasts and for tracking environmental events such as forest fires and droughts.

Image Credit: Ball Aerospace

JPSS-1 is the primary satellite launching, but four tiny satellites will also be hitchhiking a ride into Earth orbit. These shoebox-sized satellites (part of our CubeSat Launch Initiative) were developed in partnership with university students and used for education, research and development. Here are 4 reasons why MiRaTA, one of the hitchhikers, is particularly interesting…

Miniaturized Weather Satellite Technology

The Microwave Radiometer Technology Acceleration (MiRaTA) CubeSat is set to orbit the Earth to prove that a small satellite can advance the technology necessary to reduce the cost and size of future weather satellites. At less than 10 pounds, these nanosatellites are faster and more cost-effective to build and launch since they have been constructed by Principal Investigator Kerri Cahoy’s students at MIT Lincoln Laboratory (with lots of help). There’s even a chance it could be put into operation with forecasters.

The Antenna? It’s a Measuring Tape

That long skinny piece coming out of the bottom right side under MiRaTA’s solar panel? That’s a measuring tape. It’s doubling as a communications antenna. MiRaTA will measure temperature, water vapor and cloud ice in Earth’s atmosphere. These measurements are used to track major storms, including hurricanes, as well as everyday weather. If this test flight is successful, the new, smaller technology will likely be incorporated into future weather satellites – part of our national infrastructure.

Tiny Package Packing a Punch MiRaTA will also test a new technique using radio signals received from GPS satellites in a higher orbit. They will be used to measure the temperature of the same volume of atmosphere that the radiometer is viewing. The GPS satellite measurement can then be used for calibrating the radiometer. “In physics class, you learn that a pencil submerged in water looks like it’s broken in half because light bends differently in the water than in the air,” Principal Investigator Kerri Cahoy said. “Radio waves are like light in that they refract when they go through changing densities of air, and we can use the magnitude of the refraction to calculate the temperature of the surrounding atmosphere with near-perfect accuracy and use this to calibrate a radiometer.” 

What’s Next?

In the best-case scenario, three weeks after launch MiRaTA will be fully operational, and within three months the team will have obtained enough data to study if this technology concept is working. The big goal for the mission—declaring the technology demonstration a success—would be confirmed a bit farther down the road, at least half a year away, following the data analysis. If MiRaTA’s technology validation is successful, Cahoy said she envisions an eventual constellation of these CubeSats orbiting the entire Earth, taking snapshots of the atmosphere and weather every 15 minutes—frequent enough to track storms, from blizzards to hurricanes, in real time.

Learn more about MiRaTA

Watch the launch!

The mission is scheduled to launch this month (no sooner than Nov. 14), with JPSS-1 atop a United Launch Alliance (ULA) Delta II rocket lifting off from Space Launch Complex 2 at Vandenberg Air Force Base in California. You’ll be able to watch on NASA TV or at nasa.gov/live.

Watch the launch live HERE on Nov. 14, liftoff is scheduled for Tuesday, 4:47 a.m.! 

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What’s Up November 2017

What’s Up For November?

Dawn pairing of Jupiter and Venus, Moon shines near star clusters, meteor activity all month long!

This month binoculars will come in handy–to view the moon, star clusters, and a close pairing of Venus and Jupiter.

You can’t miss bright Venus in the predawn sky. This month Venus pairs up with Jupiter on the morning of November 13th.

The Leonids peak on a moonless November 17th. Expect no more than 10 meteors an hour around 3:00 a.m., the height of the shower.

The Northern and Southern sub-branches of the Taurid meteor shower offer sparse counts of about 5 meteors per hour, but slow, bright meteors are common.

The nearby November Orionids peak on the 28th. In contrast to the Taurids, the Orionids are swift. But don’t expect more than 3 meteors per hour.

The moon glides by three beautiful star clusters in the morning sky this month, and a pair of binoculars will allow you to see the individual stars in the clusters. Aim your binoculars at the Pleiades and the moon on the 5th.

Then aim at the Messier or M-35 cluster and the moon on the 7th and the Beehive cluster and the moon on the 10th.

Meanwhile, at dusk, catch Saturn as it dips closer to the western horizon and pairs up with Mercury on the 24th through the 28th.

Also, Comet C/2017 O1 should still be a binocular-friendly magnitude 7 or 8 greenish object in November. Use Polaris, the North Star as a guide. Look in the East to Northeast sky in the late evening.  

Watch the full What’s Up for November Video: 

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Saturn photographed by the Cassini spacecraft in 2014

Image credit: NASA/JPL/Cassini; precessed by: Ian Regan