Ever since the Curiosity rover landed on Mars in 2012, it has provided NASA scientists with invaluable data about the planet’s past, as well as some breathtaking images of the planet’s surface. Much like its predecessors, the Spiritand Opportunityrover, many of these images have shown what it is like to look up at the sky from the surface of Mars and witness celestial events.
Of these events, one of the most intriguing has to be the many Martian solar eclipses that have taken place since the rover’s landed. Last month, the Curiosity rover witnessed two eclipses as the moons of Phobos and Deimos both passed in front of the Sun. These latest eclipses will allow scientists to fine-tune their predictions about Mars’ satellites and how they orbit the Red Planet.
During the summer of 2018, the planets of Mars and Saturn (one after the other) have been in opposition. In astronomical terms, opposition refers to when a planet is on the opposite side of the Earth relative to the Sun. This not only means that the planet is closer to Earth in its respective orbit, but that is also fully lit by the Sun (as seen from Earth) and much more visible.
As a result, astronomers are able to observe these planets in greater detail. The Hubble Space Telescope took advantage of this situation to do what it has done best for the past twenty-eight years – capture some breathtaking images of both planets! Hubble made its observations of Saturn in June and Mars in July, and showed both planets close to their opposition.
Hubble’s high-resolution images of the planets and moons in our Solar System can only be surpassed by spacecraft that are either orbiting or conducting close flybys to them. However, Hubble has a major advantage over these types of missions, in that it can look at the Solar planets periodically and observe them over much longer periods of time than a passing spacecraft.
Hubble observed Saturn on June 6th, almost a month before it reached opposition on June 27th. At the time, the ringed gas giant was approximately 1.4 billion km (870 million mi) from Earth. Hubble was able to capture the planet’s magnificent ring system at a time when it was at its maximum tilt to Earth, which allowed for a spectacular view of the rings and the gaps between them.
Hubble’s new image of Saturn also managed to capture the hexagonal storm around the gas giant’s north pole. This stable and persistent jet stream was first observed by the Voyager 1 probe during its flyby of Saturn in 1981, and has been a mystery to astronomers ever since. On top of that, the new image also features six of Saturn’s 62 known moons – Dione, Enceladus, Tethys, Janus, Epimetheus, and Mimas.
Hubble’s new image of Mars was captured on July 18th, 13 days before it reached its closest approach to Earth. This year will see the Red Planet get as close as 57.6 million km from Earth, which is the closest approach made since 2003. On that occasion, Mars was just 55,757,930 km (34,647,420 mi) from Earth, which was the closest the planet had been to Earth in almost 60,000 years!
Mars is at opposition to Earth every two years, so Hubble has had many opportunities to capture detailed images of the planet’s surface. However, this new image is different in that it is dominated by a gigantic sandstorm that is currently encompassing the entire planet. This storm has been raging since May of 2018 and developed into a planet-wide dust storm within several weeks.
Dust storms are a common occurrence on Mars. They take place every year, usually stay contained to a local area, and normally last only about a few weeks. Larger dust storms that can grow to cover the entire planet are a rarer event, and can typically last for weeks or even months. These tend to happen during the spring and summer months in the southern hemisphere, which coincides with Mars being closer to the Sun in its elliptical orbit.
Due to increased temperatures, dust particles are lifted higher into the atmosphere, creating more wind. The resulting wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand. While spacecraft orbiting Mars and rovers and lander can study storm behavior at lower altitudes or from the surface, Hubble observations allow astronomers to study changes in the higher atmosphere.
The combined observations will help planetary scientists to better understanding how these global storms arise. Despite the obscuring dust storm, Hubble still managed to capture several important Martian surface features like the polar ice caps, Terra Meridiani, the Schiaparelli Crater, and Hellas Basin – even though all of them appear slightly blurred in the image.
The Hellas Basin – an impact basin that measures 2200 km (1367 mi) across and is nearly 8 km (4.97 mi) deep – is visible at the lower right and appears as a large and bright oval area. The orange area in the upper center of the image is Arabia Terra, a large upland area in northern Mars. This region is characterized by many impact craters and heavy erosion, which indicates that it could be among the oldest terrains on the planet.
South of Arabia Terra are the dark streaks known as Sinus Sabaeus and Sinus Meridiani, features that stretch from east to west along the equator and are made of up dark bedrock and sand deposits from ancient lava flows. Because it was autumn in the northern hemisphere when the image was taken, it is covered in a bright blanket of clouds – and clouds can also be seen above the northern and southern polar ice caps. Last, but not least, Mars’ two small moons – Phobos and Deimos – appear in the lower half of the image.
Comparing these new images of Mars and Saturn with older data gathered by Hubble, other telescopes and the many probes that have taken images of them over the years will allow astronomers to study how cloud patterns and large-scale structures on the Solar planets change over time. These latest images also show that even after almost three decades of being in operation, Hubble is still able to pull its weight!
And be sure to enjoy this video about the images acquired by Hubble, courtesy of Hubblecast:
Mars’ moon Phobos is a pretty fascinating customer! Compared to Mars other moon Deimos, Phobos (named after the Greek personification of fear) is the larger and innermost satellite of the Red Planet. Due to its rapid orbital speed, the irregularly-shaped moon orbits Mars once every 7 hours, 39 minutes, and 12 seconds. In other words, it completes over three orbits of Mar within a single Earth day.
It’s not too surprising then that during a recent observation of Mars with the Hubble space telescope, Phobos chose to photobomb the picture! It all took place in May of 2016, when while Mars was near opposition and Hubble was trained on the Red Planet to take advantage of it making its closest pass to Earth in over a decade. The well-timed sighting also led to the creation of a time-lapse video that shows the moon’s orbital path.
During an opposition, Mars and Earth are at the closest points in their respective orbits to each other. Because Mars and the Sun appear to be on directly opposite sides of Earth, the term “opposition” is used. These occur every 26 months, and once every 15 to 17 years, an opposition will coincide with Mars being at the closest point in its orbit to the Sun (perihelion).
When this happens, Mars is especially close to Earth, which makes it an ideal occasion to photograph it. The last time this occurred was on May 22nd, 2016, when Mars was and Earth were at a distance of about 76,309,874 km (47,416,757 mi or 0.5101 AU) from each other. This would place it closer to Earth than it had been in 11 years, and the Hubble space telescope was trained on Mars to take advantage of this.
A few days before Mars made its closest pass, Hubble took 13 separate exposures of the planet over the course of 22 minutes, allowing astronomers to create a time-lapse video. This worked out well, since Phobos came into view during the exposures, which led the video showing the path of the moon’s orbit. Because of its small size, Phobos looked like a star that was popping out from behind the planet.
This sighting has only served to enhance Phobos’ fascinating nature. As of 2017, astronomers have been aware of the moon’s existence for 140 years. It was discovered in 1877, when Asaph Hall – while searching for Martian moons – observed it from the U.S. Naval Observatory in Washington D.C. A few days later, he also discovered Deimos, the smaller, outer moon of Mars.
In July of 1969, just two weeks before the Apollo landing, the Mariner 7 probe conducted a flyby of Mars and took the first close-up images of the Moon. In 1977, a year after the Viking 1 lander was deployed to the Martian surface, NASA’s Viking 1 orbiter took the first detailed photographs of the moon. These revealed a cratered surface marred by long, shallow grooves and one massive crater – known as the Stickney crater.
Asaph Hall named this crater after Chloe Angeline Stickney Hall (his wife) after discovering it in 1878, a year after he discovered Phobos and Deimos. Measuring some 10 km in diameter – almost half of the average diameter of Phobos itself – the impact that created Stickney is believed to have been so powerful that it nearly shattered the moon.
The most widely-accepted theory about Phobos origins is that both it and Deimos were once asteroids that were kicked out of the Main Belt by Jupiter’s gravity, and were then acquired by Mars. But unlike Deimos, Phobos’ orbit is unstable. Every century, the moon draws closer to Mars by about 1.98 meters (6.5 feet). At this rate, scientist estimate that within 30 to 50 million years, it will crash into Mars or be torn to pieces to form a ring in orbit.
This viewing is perhaps a reminder that this satellite won’t be with Mars forever. Then again, it will certainly still be there if and when astronauts (and maybe even colonists) begin setting foot on the planet. To these people, looking up at the sky from the surface of Mars, Phobos will be seen regularly eclipsing the Sun. Because of its small size, it does not fully eclipse the Sun, but it does make transits multiple times in a single day.
So there’s still plenty of time to study and enjoy this fearfully-named moon. And while you’re at it, be sure to check out the video below, courtesy of NASA’s Goddard Space Center!
In the coming decades, the world’s largest space agencies hope to mount some exciting missions to the Moon and to Mars. Between NASA, Roscosmos, the European Space Agency (ESA), the Chinese National Space Agency (CNSA) and the Indian Space Research Organization (ISRO), there is simply no shortage of proposals for Lunar bases, crewed missions to Mars, and robotic explorers to both.
However, the Japanese Aerospace Exploration Agency (JAXA) has a different mission in mind when it comes to the coming decades. Instead of exploring the Moon or Mars, they propose exploring the moons of Mars! Known as the Martian Moons Exploration (MMX) mission, the plan is to have a robotic spacecraft fly to Phobos and Deimos to explore their surfaces and return samples to Earth for analysis.
The spacecraft would be deployed sometime in the 2020s, and would be tasked with two main objectives. The first would be to help scientists determine the origins of Phobos and Deimos, which has been a subject of debate for some time. Whereas some believe that these moons are capture asteroids, others have argued that they were created when fragments ejected from Mars (due to giant impacts on the surface) came together.
“MMX will land on Phobos and acquire samples of at least 10 grams from more than 2cm below the surface. Analysis of samples returned to Earth will clarify the nature of the asteroid that led to the formation of the moon. Deimos observations will be limited to flyby imaging, but combined with ground data to be obtained for Phobos, we should be able to constrain its origin in a substantial manner.”
The second objective focuses on the characterization of conditions both on and around the moons of Mars. This includes surface processes on Phobos and Deimos, the nature of the environment in which they orbit, and the global and temporal dynamics of Mars atmosphere – i.e. dust, clouds and water vapor.
“Airless bodies such as asteroids are exposed to space weathering processes,” said Dr. Fujimoto. “In the case of Phobos, an impact event on the surface releases many dust particles. Unlike an asteroid in the interplanetary space, dust particles will not be simply lost but will orbit around Mars and return and hit the Phobos surface. This is regarded as the reason that Phobos has a very thick regolith layer. Knowing this process is to know the attributes of returned samples better.”
Another major objective of this mission is to learn more about small bodies coming from the outer Solar System. As the outermost rocky planet, Mars’ orbit marks the boundary between the terrestrial planets – which have solid surfaces and variable atmospheres (ranging from super-thing to dense) – and the gas and ice giants of the outer Solar System that have highly dense atmospheres.
Because of this, studying Mars’ moons, determining their origin, and learning more about the Martian orbital environment could teach us a lot about the evolution of the Solar System. Not only does such a mission present opportunities to study how planets like Mars formed, but also the process of by which primordial materials were transported between the inner and outer Solar Systems during its early history. As Dr. Fujimoto explained:
“These small bodies were the delivery capsules for water from outside the Frost Line to the Habitable Zone of the solar system, where our planet is situated. Earth was born dry and needed delivery of water for its habitability to be switched on at all. It is likely that one of the (failed) deliveries led to the formation of Phobos, and, sample analysis will tell us about the failed capsule.
“This is obviously the case when the capture idea turns out to be correct. Even for the case of giant impact, the scale of the impact is considered to be not too gigantic to alter fully the materials, implying that sample analysis would tell us something about the impactor asteroid.”
As it stands, the probe is scheduled to launch in September 2024, taking advantage of the fact that Earth and Mars will be at the nearest point to each other in their orbits at this time. It will arrive around Mars by 2025, conduct its studies for a three-year period, and then return to Earth by July of 2029. Once there, it will rely on a suite of scientific instruments to conduct surveys and obtain samples.
These instruments include a Neutron and Gamma-ray Spectrometer (NGRS), a Near-Infrared Spectrometer (NIRS), a Wide Angle Multiband Camera (WAM), a Telescopic Camera (TL), a Circum-Martian Dust Monitor (CMDM), a Mass Spectrum Analyzer (MSA), and a Light Detection and Ranging (LIDAR) instrument.
The mission will also leverage some key partnerships that JAXA is currently engaged in. These include an agreement reached with NASA back in late March to include the Neutron and Gamma-ray Spectrometer (NGRS) in the MMX’s instrument suite. And in April, JAXA and the National Center for Space Studies (CNES) signed an Implementation Agreement (IA) that would allow the French national space agency to participate in the mission as well.
If all goes as planned, JAXA will be spending the next decade gathering information that could bridge findings made by Lunar and Martian missions. Whereas lunar research will reveal things about the history of the Moon, and Martian missions will offer new insights into Mars’ geology and evolution (and perhaps if life still exists there!), the MMX mission will reveal things about the history of Mars’ moons and the early Solar System as a whole.
Other proposals that JAXA is currently working on include the Jupiter Icy Moons Explorer (JUICE) and SPICA, two missions that will explore Jupiter’s Galilean Moons and conduct infrared astronomy (respectively) in the coming decade.
Virtually every planet in the Solar System has moons. Earth has The Moon, Mars has Phobos and Deimos, and Jupiter and Saturn have 67 and 62 officially named moons, respectively. Heck, even the recently-demoted dwarf planet Pluto has five confirmed moons – Charon, Nix, Hydra, Kerberos and Styx. And even asteroids like 243 Ida may have satellites orbiting them (in this case, Dactyl). But what about Mercury?
If moons are such a common feature in the Solar System, why is it that Mercury has none? Yes, if one were to ask how many satellites the planet closest to our Sun has, that would be the short answer. But answering it more thoroughly requires that we examine the process through which other planets acquired their moons, and seeing how these apply (or fail to apply) to Mercury.
Where did Mars’ moons Phobos and Deimos come from? How did they end up in orbit around Mars? This cool video from the folks at Kurzgesagt answers the most-oft asked questions about these mini moons.
You should also check out their other wonderful videos, like the one about our own Moon, below, which explains how big our Moon really is. The answer might surprise you.
Who is Kurzgesagt? They are video designers who create fun and intellectually stimulating content about space, science and many other topics. “Kurz gesagt” is a German expression for “to make a long story short” and the Kurzgesagt team says it precisely conveys their goal to present complex topics in a short and understandable way to the world. “Also, we want to make stuff that simply looks awesome.”
Mission accomplished! Look for more videos from Kurzgesagt on Universe Today in the future.
Mars moon Phobos (above, center) rising in the night time Martian sky shortly after sunset in this still image from a movie taken by NASA’s Mars rover Curiosity on Sol 317, June 28, 2013. The apparent ring is an imaging artifact. Credit: NASA/JPL-Caltech See the complete ‘Phobos Rising’ movie below [/caption]
Every once in a while when the time is just right and no one is looking, Curiosity’s Earthly handlers allow her some night time Martian delights.
In this case a pair of rising and setting celestial events bookend another magnificent week in humankinds exploration of the Red Planet – courtesy of NASA.
This past week NASA’s Curiosity rover captured esthetically stunning imagery of Phobos rising and Our Sun setting on Mars.
Phobos is the larger of Mars pair of tiny moons. The other being Diemos.
On June 28, (Sol 317) Curiosity aimed her navigation camera straight overhead to captured a breathtaking series of 86 images as Phobos was ascending in the alien evening sky shortly after sunset.
NASA combined these raw images taken over about 27 minutes into a short movie clip, sped up from real time.
Video Caption: ‘Phobos Rising’ – This movie clip shows Phobos, the larger of the two moons of Mars, passing overhead, as observed by NASA’s Mars rover Curiosity in a series of images centered straight overhead starting shortly after sunset. Phobos first appears near the lower center of the view and moves toward the top of the view. The images were taken on June 28, 2013. The apparent ring is an imaging artifact. Credit: NASA/JPL-Caltech
The pockmarked and potato shaped moon measures about 26.8 × 22.4 × 18.4 kilometers.
In less than 48 hours, Russia’s bold Phobos-Grunt mechanized probe will embark on a historic flight to haul humanities first ever soil samples back from the tiny Martian moon Phobos. Liftoff from the Baikonur Cosmodrome remains on target for November 9 (Nov 8 US 3:16 p.m. EDT).
For an exquisite view of every step of this first-of-its-kind robot retriever, watch this spectacular action packed animation (below) outlining the entire 3 year round trip voyage. The simulation was produced by Roscosmos, Russia’s Federal Space Agency and the famous IKI Space Research Institute. It’s set to cool music – so don’t’ worry, you don’t need to understand Russian.
The highly detailed animation begins with the blastoff of the Zenit booster rocket and swiftly progresses through Earth orbit departure, Phobos-Grunt Mars orbit insertion, deployment of the piggybacked Yinghuo-1 (YH-1) mini satellite from China, Phobos-Grunt scientific reconnaissance of Phobos and search for a safe landing site, radar guided propulsive landing, robotic arm manipulation and soil sample collection and analysis, sample transfer to the Earth return capsule and departure, plummeting through Earth’s atmosphere and Russian helicopter retrieval of the precious cargo carrier.
Video Caption: Every step of Russia’s Phobos-Grunt soil retrieval mission. Credit: Roscosmos/IKI
Video Caption: On October 21, the Phobos-Grunt spacecraft arrived at the Baikonur Cosmodrome and was uncrated and moved to assembly building 31 for fueling, final preflight processing and encapsulation in the nose cone. Credit: Roscosmos
Technicians also fueled the companion Yinghou-1 mini-satellite, provided by China, that will ride along inside a truss segment between the MDU propulsion module and the Phobos-Grunt lander.
The 12,000 kg Phobos-Grunt interplanetary spacecraft is being moved to an integration and test area at Facility 31 for integration with the departure segments of the Zenit rocket.
The next step is to enclose Phobos-Grunt inside the protective payload fairing and transport it to Facility 42 for mating atop the upper stage of the stacked Zenit-2SB booster rocket.
After about an 11 month journey, the spaceship will enter Mars orbit and spend several months searching for a suitable landing site on Phobos. The goal of the bold mission is to retrieve up to 200 grams of soil and rock from Phobos and return them to Earth in August 2014. The samples will help unlock the mysteries of the origin and evolution of Phobos, Mars and the Solar System.
Phobos-Grunt is equipped with a powerful 50 kg payload of some 20 international science instruments.
The 110 kg Yinghou-1, which translates as Firefly-1, is China’s first spaceship to voyage to Mars. It will be jettisoned by Phobos-Grunt into a separate orbit about Mars. The probe will photograph the Red planet with two cameras and study it with a magnetometer to explore Mars’ magnetic field and science instruments to explore its upper atmosphere.
Russia is marking the upcoming blastoff of their dauntingly complex Phobos-Grunt sample return mission to the Martian moon Phobos with the release of a quite cool looking mission poster – see above. Phobos-Grunt translates as Phobos-Soil and is due to liftoff on or about November 7, 2011 from the Baikonur Cosmodrome atop a Zenit rocket.
The holy grail of Mars exploration has long been a sample return mission. But with severe cutbacks to NASA’s budget that goal is realistically more than a decade away. That’s why Phobos- Grunt is so exciting from a scientific standpoint.
If successful, this audacious probe will retrieve about 200 grams of soil from the diminutive moon Phobos and accomplish the round trip in three years time by August 2014. Scientists speculate that martian dust may coat portions of Phobos and could possibly be mixed in with any returned samples.
Included here are more photos and graphics of the Phobos-Grunt spacecraft which is equipped with two robotic arms and a sampling device to transfer regolith and rocks to the Earth return vehicle and an on board array of some 15 science instruments, including lasers, spectrometers, cameras and a microscope. Readers please feel free to help with Russian translations.
Phobos-Grunt is the first of Earth’s two missions launching to the Red Planet in 2011. NASA’s Curiosity Mars Science Laboratory is due to lift off on Nov. 25, 2011 from Cape Canaveral, Florida.