One year ago, on Sept. 15, 2017, NASA’s Cassini spacecraft ended
its epic exploration of Saturn with a planned dive into the planet’s
atmosphere–sending back new science to the last second. The spacecraft is
gone, but the science continues. Here are 10 reasons why Cassini mattered…
Cassini and ESA (European Space Agency)’s Huygens probe expanded our understanding of the
kinds of worlds where life might exist.
2. A (Little) Like Home
At Saturn’s largest moon, Titan, Cassini and Huygens showed us one of the most Earth-like worlds we’ve
ever encountered, with weather, climate and geology that provide new ways to
understand our home planet.
3. A Time Machine (In a Sense)
Cassini gave us a portal to see the physical processes that likely
shaped the development of our solar system, as well as planetary systems around
4. The Long Run
The length of Cassini’s mission enabled us to observe weather and
seasonal changes over nearly half of a Saturn year, improving our understanding
of similar processes at Earth, and potentially those at planets around other
5. Big Science in Small Places
Cassini revealed Saturn’s moons to be unique worlds with their own
stories to tell.
Cassini showed us the complexity of Saturn’s rings and the
dramatic processes operating within them.
7. Pure Exploration
Some of Cassini’s best discoveries were serendipitous. What
Cassini found at Saturn prompted scientists to rethink their understanding of
the solar system.
8. The Right Tools for the Job
Cassini represented a staggering achievement of human and
technical complexity, finding innovative ways to use the spacecraft and its
instruments, and paving the way for future missions to explore our solar
9. Jewel of the Solar System
Cassini revealed the beauty of Saturn, its rings and moons,
inspiring our sense of wonder and enriching our sense of place in the cosmos.
Outstanding views Venus, Jupiter, Saturn and Mars with the naked eye!
You’ll have to look quickly after sunset to catch Venus. And through binoculars or a telescope, you’ll see Venus’s phase change dramatically during September – from nearly half phase to a larger thinner crescent!
Jupiter, Saturn and Mars continue their brilliant appearances this month. Look southwest after sunset.
Use the summer constellations help you trace the Milky Way.
Sagittarius: where stars and some brighter clumps appear as steam from the teapot.
Aquila: where the Eagle’s bright Star Altair, combined with Cygnus’s Deneb, and Lyra’s Vega mark the Summer Triangle.
Cassiopeia, the familiar “w”- shaped constellation completes the constellation trail through the Summer Milky Way. Binoculars will reveal double stars, clusters and nebulae.
Between September 12th and the 20th, watch the Moon pass from near Venus, above Jupiter, to the left of Saturn and finally above Mars!
Both Neptune and brighter Uranus can be spotted with some help from a telescope this month.
Look at about 1:00 a.m. local time or later in the southeastern sky. You can find Mercury just above Earth’s eastern horizon shortly before sunrise. Use the Moon as your guide on September 7 and 8th.
And although there are no major meteor showers in September, cometary dust appears in another late summer sight, the morning Zodiacal light. Try looking for it in the east on moonless mornings very close to sunrise. To learn more about the Zodiacal light, watch “What’s Up” from March 2018.
Our flying observatory SOFIA carries a telescope inside this Boeing 747SP aircraft. Scientists use SOFIA to study the universe — including stars, planets and black holes — while flying as high as 45,000 feet.
SOFIA is typically based at our Armstrong Flight Research Center in Palmdale, California, but recently arrived in Christchurch, New Zealand, to study celestial objects that are best observed from the Southern Hemisphere.
So what will we study from the land down under?
Eta Carinae, in the southern constellation Carina, is the most luminous stellar system within 10,000 light-years of Earth. It’s made of two massive stars that are shrouded in dust and gas from its previous eruptions and may one day explode as a supernova. We will analyze the dust and gas around it to learn how this violent system evolves.
Celestial Magnetic Fields
We can study magnetic fields in the center of our Milky Way galaxy from New Zealand because there the galaxy is high in the sky — where we can observe it for long periods of time. We know that this area has strong magnetic fields that affect the material spiraling into the black hole here and forming new stars. But we want to learn about their shape and strength to understand how magnetic fields affect the processes in our galactic center.
Saturn’s Moon Titan
Titan is Saturn’s largest moon and is the only moon in our solar system to have a thick atmosphere — it’s filled with a smog-like haze. It also has seasons, each lasting about seven Earth years. We want to learn if its atmosphere changes seasonally.
Titan will pass in front of a star in an eclipse-like event called an occultation. We’ll chase down the shadow it casts on Earth’s surface, and fly our airborne telescope directly in its center.
From there, we can determine the temperature, pressure and density of Titan’s atmosphere. Now that our Cassini Spacecraft has ended its mission, the only way we can continue to monitor its atmosphere is by studying these occultation events.
The Large Magellanic Cloud is a galaxy near our own, but it’s only visible from the Southern Hemisphere! Inside of it are areas filled with newly forming stars and the leftovers from a supernova explosion.
The Tarantula Nebula
The Tarantula Nebula, also called 30 Doradus, is located in the Large Magellanic Cloud and shown here in this image from Chandra, Hubble and Spitzer. It holds a cluster of thousands of stars forming simultaneously. Once the stars are born, their light and winds push out the material leftover from their parent clouds — potentially leaving nothing behind to create more new stars. We want to know if the material is still expanding and forming new stars, or if the star-formation process has stopped. So our team on SOFIA will make a map showing the speed and direction of the gas in the nebula to determine what’s happening inside it.
Also in the Large Magellanic Cloud is Supernova 1987A, the closest supernova explosion witnessed in almost 400 years. We will continue studying this supernova to better understand the material expanding out from it, which may become the building blocks of future stars and planets. Many of our telescopes have studied Supernova 1987A, including the Hubble Space Telescope and the Chandra X-ray Observatory, but our instruments on SOFIA are the only tools we can use to study the debris around it with infrared light, which let us better understand characteristics of the dust that cannot be measured using other wavelengths of light.
Jupiter and Venus at sunset, Mars, Saturn and Vesta until dawn.
First up is Venus. It reaches its highest sunset altitude for the year this month and sets more than two hours after sunset.
You can’t miss Jupiter, only a month after its opposition–when Earth was directly between Jupiter and the Sun.
The best time to observe Jupiter through a telescope is 10:30 p.m. at the beginning of the month and as soon as it’s dark by the end of the month.
Just aim your binoculars at the bright planet for a view including the four Galilean moons. Or just enjoy Jupiter with your unaided eye!
Saturn is at opposition June 27th, when it and the Sun are on opposite sides of Earth. It rises at sunset and sets at sunrise. Great Saturn viewing will last several more months. The best views this month will be just after midnight.
All year, the rings have been tilted wide open–almost 26 degrees wide this month–giving us a great view of Saturn’s distinctive rings.
The tilt offers us a view of the north polar region, so exquisitely imaged by the Cassini spacecraft.
Near Saturn, the brightest asteroid–Vesta–is so bright that it can be seen with your unaided eye. It will be visible for several months.
A detailed star chart will help you pick out the asteroid from the stars. The summer Milky way provides a glittery backdrop.
Finally, Mars grows dramatically in brightness and size this month and is visible by 10:30 p.m. by month end.
The best views are in the early morning hours. Earth’s closest approach with Mars is only a month away. It’s the closest Mars has been to us since 2003.
The Moon, Mars and Saturn and the Lyrid meteor shower!
The Moon, Mars and Saturn
The Moon, Mars and Saturn form a pretty triangle in early April, the Lyrid Meteors are visible in late April, peaking high overhead on the 22nd.
You won’t want to miss red Mars and golden Saturn in the south-southeast morning skies this month. Mars shines a little brighter than last month.
By the 7th, the Moon joins the pair. From a dark sky you may see some glow from the nearby Milky Way.
Midmonth, start looking for Lyrid meteors, which are active from April 14 through the 30th. They peak on the 22nd.
The Lyrids are one of the oldest known meteor showers and have been observed for 2,700 years. The first recorded sighting of a Lyrid meteor shower goes back to 687 BC by the Chinese. The pieces of space debris that interact with our atmosphere to create the Lyrids originate from comet C/1861 G1 Thatcher. Comet Thatcher was discovered on 5 April 1861 by A. E. Thatcher.
In the early morning sky, a patient observer will see up to more than a dozen meteors per hour in this medium-strength shower, with 18 meteors per hour calculated for the peak. U.S. observers should see good rates on the nights before and after this peak.
A bright first quarter moon plays havoc with sky conditions, marring most of the typically faint Lyrid meteors. But Lyra will be high overhead after the moon sets at midnight, so that’s the best time to look for Lyrids.
Jupiter & Juno
Jupiter will also be visible in the night sky this month!
Through a telescope, Jupiter’s clouds belts and zones are easy to see.
And watch the Great Red Spot transit–or cross–the visible (Earth-facing) disk of Jupiter every 8 hours.
Our Juno spacecraft continues to orbit this gas giant, too!
And Juno’s JunoCam citizen science team is creating exciting images of Jupiter’s features based on the latest spacecraft data.
Next month Jupiter is at opposition–when it rises at sunset, sets at sunrise, and offers great views for several months!
2—Four Hundred Elephants…The Saturn V rocket stood about the height of a 36-story-tall building, and 60 feet (18 meters) taller than the Statue of Liberty. Fully fueled for liftoff, the Saturn V weighed 6.2 million pounds (2.8 million kilograms), or the weight of about 400 elephants.Rockets We Love-Saturn V
Fifty years ago, with President Kennedy’s Moon landing deadline looming, the powerful Saturn V had to perform. And perform it did—hurling 24 humans to the Moon.
The race to land astronauts on the Moon was getting tense 50 years ago this week. Apollo 6, the final uncrewed test flight of America’s powerful Moon rocket, launched on April 4, 1968. Several technical issues made for a less-than-perfect launch, but the test flight nonetheless convinced NASA managers that the rocket was up to the task of carrying humans. Less than two years remained to achieve President John F. Kennedy’s goal to put humans on the Moon before the decade was out, meaning the Saturn V rocket had to perform.
1—“The only chance to get to the Moon before the end of 1969.”
After the April 1968 Apollo 6 test flight (pictured above), the words of Deke Slayton (one of the original Mercury 7 astronauts) and intense competition with a rival team in the Soviet Union propelled a 12-member panel to unanimously vote for a Christmas 1968 crewed mission to orbit the Moon.
2—Four Hundred Elephants…
The Saturn V rocket stood about the height of a 36-story-tall building, and 60 feet (18 meters) taller than the Statue of Liberty. Fully fueled for liftoff, the Saturn V weighed 6.2 million pounds (2.8 million kilograms), or the weight of about 400 elephants.
3—…and Busloads of Thrust
Stand back, Ms. Frizzle. The Saturn V generated 7.6 million pounds (34.5 million newtons) of thrust at launch, creating more power than 85 Hoover Dams. It could launch about 130 tons (118,000 kilograms) into Earth orbit. That’s about as much weight as 10 school buses. The Saturn V could launch about 50 tons (43,500 kilograms) to the Moon. That’s about the same as four school buses.
4—Christmas at the Moon
On Christmas Eve 1968, the Saturn V delivered on engineers’ promises by hurling Frank Borman, Jim Lovell and Bill Anders into lunar orbit. The trio became the first human beings to orbit another world. The Apollo 8 crew broadcast a special holiday greeting from lunar orbit and also snapped the iconic earthrise image of our home planet rising over the lunar landscape.
5—Gumdrop and Spider
The crew of Apollo 9 proved that they could pull the lunar module out of the top of the Saturn V’s third stage and maneuver it in space (in this case high above Earth). The crew named their command module “Gumdrop.” The Lunar Module was named “Spider.”
6—The Whole Enchilada
Saturn-V AS-505 provided the ride for the second dry run to the Moon in 1969. Tom Stafford, Gene Cernan and John Young rode Command Module “Charlie Brown” to lunar orbit and then took Lunar Module “Snoopy” on a test run in lunar orbit. Apollo 10 did everything but land on the Moon, setting the stage for the main event a few months later. Young and Cernan returned to walk on the Moon aboard Apollo 16 and 17 respectively. Cernan, who died in 2017, was the last human being (so far) to set foot on the Moon.
7—The Main Event
The launch of Apollo 11—the first mission to land humans on the Moon—provided another iconic visual as Saturn-V AS-506 roared to life on Launch Pad 39A at Kennedy Space Center in Florida. Three days later, Neil Armstrong and Buzz Aldrin made the first of many bootprints in the lunar dust (supported from orbit by Michael Collins).
Saturn V rockets carried 24 humans to the Moon, and 12 of them walked on its surface between 1969 and 1972. Thirteen are still alive today. The youngest, all in their early 80s, are moonwalkers Charles Duke (Apollo 16) and Harrison Schmitt (Apollo 17) and Command Module Pilot Ken Mattingly (Apollo 16, and also one of the heroes who helped rescue Apollo 13). There is no single image of all the humans who have visited the Moon.
This was the last launch of a Saturn V, but you can still see the three remaining giant rockets at the visitor centers at Johnson Space Center in Texas and Kennedy Space Center in Florida and at the United States Space and Rocket Center in Alabama (near Marshall Space Flight Center, one of the birthplaces of the Saturn V).
10—The Next Generation
The Saturn V was retired in 1973. Work is now underway on a fleet of rockets. We are planning an uncrewed flight test of Space Launch System (SLS) rocket to travel beyond the Moon called Exploration Mission-1 (EM-1). “This is a mission that truly will do what hasn’t been done and learn what isn’t known,” said Mike Sarafin, EM-1 mission manager at NASA Headquarters in Washington.
Read the web version of this 10 Things to Know article HERE.
Someone’s got to be first. In space, the first explorers beyond Mars were Pioneers 10 and 11, twin robots who charted the course to the cosmos.
Voyager, with its outer solar system tour and interstellar observations, is often credited as the greatest robotic space mission. But today we remember the plucky Pioneers, the spacecraft that proved Voyager’s epic mission was possible.
2-Where No One Had Gone Before
Forty-five years ago this week, scientists still weren’t sure how hard it would be to navigate the main asteroid belt, a massive field of rocky debris between Mars and Jupiter. Pioneer 10 helped them work that out, emerging from first the first six-month crossing in February 1973. Pioneer 10 logged a few meteoroid hits (fewer than expected) and taught engineers new tricks for navigating farther and farther beyond Earth.
3-Trailblazer No. 2
Pioneer 11 was a backup spacecraft launched in 1973 after Pioneer 10 cleared the asteroid belt. The new mission provided a second close look at Jupiter, the first close-up views of Saturn and also gave Voyager engineers plotting an epic multi-planet tour of the outer planets a chance to practice the art of interplanetary navigation.
4-First to Jupiter
Three-hundred and sixty-three years after humankind first looked at Jupiter through a telescope, Pioneer 10 became the first human-made visitor to the Jovian system in December 1973. The spacecraft spacecraft snapped about 300 photos during a flyby that brought it within 81,000 miles (about 130,000 kilometers) of the giant planet’s cloud tops.
Pioneer began as a Moon program in the 1950s and evolved into increasingly more complicated spacecraft, including a Pioneer Venus mission that delivered a series of probes to explore deep into the mysterious toxic clouds of Venus. A family portrait (above) showing (from left to right) Pioneers 6-9, 10 and 11 and the Pioneer Venus Orbiter and Multiprobe series. Image date: March 11, 1982.
6-A Pioneer and a Pioneer
Classic rock has Van Halen, we have Van Allen. With credits from Explorer 1 to Pioneer 11, James Van Allen was a rock star in the emerging world of planetary exploration. Van Allen (1914-2006) is credited with the first scientific discovery in outer space and was a fixture in the Pioneer program. Van Allen was a key part of the team from the early attempts to explore the Moon (he’s pictured here with Pioneer 4) to the more evolved science platforms aboard Pioneers 10 and 11.
7-The Farthest…For a While
For more than 25 years, Pioneer 10 was the most distant human-made object, breaking records by crossing the asteroid belt, the orbit of Jupiter and eventually even the orbit of Pluto. Voyager 1, moving even faster, claimed the most distant title in February 1998 and still holds that crown.
We last heard from Pioneer 10 on Jan. 23, 2003. Engineers felt its power source was depleted and no further contact should be expected. We tried again in 2006, but had no luck. The last transmission from Pioneer 11 was received in September 1995. Both missions were planned to last about two years.
9-Galactic Ghost Ships
Pioneers 10 and 11 are two of five spacecraft with sufficient velocity to escape our solar system and travel into interstellar space. The other three—Voyagers 1 and 2 and New Horizons—are still actively talking to Earth. The twin Pioneers are now silent. Pioneer 10 is heading generally for the red star Aldebaran, which forms the eye of Taurus (The Bull). It will take Pioneer over 2 million years to reach it. Pioneer 11 is headed toward the constellation of Aquila (The Eagle) and will pass nearby in about 4 million years.
10-The Original Message to the Cosmos
Years before Voyager’s famed Golden Record, Pioneers 10 and 11 carried the original message from Earth to the cosmos. Like Voyager’s record, the Pioneer plaque was the brainchild of Carl Sagan who wanted any alien civilization who might encounter the craft to know who made it and how to contact them. The plaques give our location in the galaxy and depicts a man and woman drawn in relation to the spacecraft.
Read the full version of this week’s 10 Things article HERE.
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1. The Fault in Our Mars
This image from our Mars Reconnaissance Orbiter (MRO) of northern Meridiani Planum shows faults that have disrupted layered deposits. Some of the faults produced a clean break along the layers, displacing and offsetting individual beds.
Our Juno spacecraft captured this image when the spacecraft was only 11,747 miles (18,906 kilometers) from the tops of Jupiter’s clouds – that’s roughly as far as the distance between New York City and Perth, Australia. The color-enhanced image, which captures a cloud system in Jupiter’s northern hemisphere, was taken on Oct. 24, 2017, when Juno was at a latitude of 57.57 degrees (nearly three-fifths of the way from Jupiter’s equator to its north pole) and performing its ninth close flyby of the gas giant planet.
After more than 13 years at Saturn, and with its fate sealed, our Cassini spacecraft bid farewell to the Saturnian system by firing the shutters of its wide-angle camera and capturing this last, full mosaic of Saturn and its rings two days before the spacecraft’s dramatic plunge into the planet’s atmosphere on Sept. 15, 2017.
Saturn’s moon Enceladus drifts before the rings, which glow brightly in the sunlight. Beneath its icy exterior shell, Enceladus hides a global ocean of liquid water. Just visible at the moon’s south pole (at bottom here) is the plume of water ice particles and other material that constantly spews from that ocean via fractures in the ice. The bright speck to the right of Enceladus is a distant star. This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 6, 2011.
Our Solar Dynamics Observatory came across an oddity this week that the spacecraft has rarely observed before: a dark filament encircling an active region (Oct. 29-31, 2017). Solar filaments are clouds of charged particles that float above the Sun, tethered to it by magnetic forces. They are usually elongated and uneven strands. Only a handful of times before have we seen one shaped like a circle. (The black area to the left of the brighter active region is a coronal hole, a magnetically open region of the Sun).
See Jupiter’s southern hemisphere in beautiful detail in this image taken by our Juno spacecraft. The color-enhanced view captures one of the white ovals in the “String of Pearls,” one of eight massive rotating storms at 40 degrees south latitude on the gas giant planet. The image was taken on Oct. 24, 2017, as Juno performed its ninth close flyby of Jupiter. At the time the image was taken, the spacecraft was 20,577 miles (33,115 kilometers) from the tops of the clouds of the planet.
Our Cassini spacecraft obtained this panoramic view of Saturn’s rings on Sept. 9, 2017, just minutes after it passed through the ring plane. The view looks upward at the southern face of the rings from a vantage point above Saturn’s southern hemisphere.
This sequence of images from our Solar Dynamics Observatory shows the Sun from its surface to its upper atmosphere all taken at about the same time (Oct. 27, 2017). The first shows the surface of the sun in filtered white light; the other seven images were taken in different wavelengths of extreme ultraviolet light. Note that each wavelength reveals somewhat different features. They are shown in order of temperature, from the first one at about 11,000 degrees Fahrenheit (6,000 degrees Celsius) on the surface, out to about 10 million degrees in the upper atmosphere. Yes, the sun’s outer atmosphere is much, much hotter than the surface. Scientists are getting closer to solving the processes that generate this phenomenon.
This orthographic projection shows dwarf planet Ceres as seen by our Dawn spacecraft. The projection is centered on Occator Crater, home to the brightest area on Ceres. Occator is centered at 20 degrees north latitude, 239 degrees east longitude.
This image from our Mars Reconnaissance Orbiter shows a small portion of the floor of Coprates Chasma, a large trough within the Valles Marineris system of canyons. Although the exact sequence of events that formed Coprates Chasma is unknown, the ripples, mesas, and craters visible throughout the terrain point to a complex history involving multiple mechanisms of erosion and deposition. The main trough of Coprates Chasma ranges from 37 miles (60 kilometers) to 62 miles (100 kilometers) in width.