The Indian Space Research Organization (ISRO) has made immense progress since the turn of the century. From its humble beginnings, launching satellites into orbit between 1975 and 2000, the ISRO sent their first mission to the Moon in October of 2008 (the Chandrayaan-1 orbiter), followed by their first mission to Mars – the Mars Orbiter Mission (MOM) – in November of 2013.
And in the coming years, the ISRO intends to become the fourth space agency to send astronauts into space. In so doing, they will join an exclusive club of space agencies that consists of only Russia, the United States and China. Last week (on September 7th, 2018) the organization unveiled the spacesuit that their astronauts will be wearing when they make this historic journey.
Martian dust storms are a pretty common occurrence, and generally happen whenever the southern hemisphere is experiencing summer. Though they can begin quite suddenly, these storms typically stay contained to a local area and last only about a few weeks. However, on occasion, Martian dust storms can grow to become global phenomena, covering the entire planet.
One such storm began back in May, starting in the Arabia Terra region and then spreading to become a planet-wide dust storm within a matter of weeks. This storm caused the skies over the Perseverance Valley, where the Opportunity rover is stationed, to become darkened, forcing the rover into hibernation mode. And while no word has been heard from the rover, NASA recently indicated that the dust storm will dissipate in a matter of weeks.
The update was posted by NASA’s Mars Exploration Program, which oversees operations for the Opportunity and Curiosity rovers, as well as NASA’s three Mars orbiters (Mars Odyssey, MRO, and MAVEN) and the Insight lander (which will land on Mars in 109 days). According to NASA, the storm is beginning to end, though it may be weeks or months before the skies are clear enough for Opportunity to exit its hibernation mode.
As noted, dust storms occur on Mars when the southern hemisphere experiences summer, which coincides with the planet 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.
Since the southern polar region is pointed towards the Sun in the summer, carbon dioxide frozen in the polar cap evaporates. This has the effect of thickening the atmosphere and increasing the surface pressure, which enhances the process by helping suspend dust particles in the air. In some cases, the dust clouds can reach up to 60 km (40 mi) or more in elevation.
Planet-wide dust storms are a relatively rare occurrence on Mars, taking place every three to four Martian years (the equivalent of approximately 6 to 8 Earth years). Such storms have been viewed many times in the past by missions like Mariner 9 (1971), Viking I (1971) and the Mars Global Surveyor (2001). In 2007, a similar storm took place that darkened the skies over where Opportunity was stationed – which led to two weeks of minimal operations and no communications.
While smaller and less intense the storm that took place back in 2007, the current storm intensified to the point where it led to a level of atmospheric opacity that is much worse than the 2007 storm. In effect, the amount of dust in the atmosphere created a state of perpetual night over the rover’s location in Perseverance Valley, which forced the rover’s science team to suspend operations.
This is due to the fact that Opportunity – unlike the Curiosity rover, which runs on nuclear-powered battery – relies on solar panels to keep its batteries charged. But beyond suspending operations, the prolonged dust storm also means that the rover might not be to keep its energy-intensive survival heaters running – which protect its batteries from the extreme cold of Mars’ atmosphere.
Luckily, NASA scientists who have been observing the global event indicated that, as of last Monday (July 23rd), more dust was falling out of the planet’s thin air than was being raised into it. This means that the global weather event has reached its decay phase, where dust-raising events either become confined to smaller areas or stop altogether.
Using its Mars Color Imager (MARCI) and Mars Climate Sounder (MCS), NASA’s Mars Reconnaissance Orbiter (MRO) also noted surface features were beginning to reappear and that temperatures in the middle atmosphere were no longer rising – which indicates less solar heating by dust. The Curiosity rover also noted a decline in dust above its position in the Gale Crater on the other side of the planet.
This is certainly good new for the Opportunity rover, though scientists expect that it will still be a few weeks or months before its solar panels can draw power again and communications can be reestablished. The last time communications took place with the rover was on June 10th, but if there’s one thing the Opportunity rover is known for, it’s endurance!
When the rover first landed on Mars on January 25th, 2004, its mission was only expected to last ninety Martian days (sols), which is the equivalent of about 92.5 Earth days. However, as of the writing of this article, the rover has endured for 14 years and 195 days, effectively exceeding its operational lifespan 55 times over. So if any rover can survive this enduring dust storm, its Opportunity!
In the meantime, multiple NASA missions are actively monitoring the storm in support of Opportunity and to learn more about the mechanics of Martian storms. By learning more about what causes these storms, and how smaller ones can merge to form global events, future robotic missions, crewed missions and (quite possibly) Martian colonists will be better prepared to deal with them.
In the coming decades, NASA and other space agencies hope to mount some ambitious missions to other planets in our Solar System. In addition to studying Mars and the outer Solar System in greater detail, NASA intends to send a mission to Venus to learn more about the planet’s past. This will include studying Venus’ upper atmosphere to determine if the planet once had liquid water (and maybe even life) on its surface.
In order to tackle this daunting challenge, NASA recently partnered with Black Swift Technologies – a Boulder-based company specializing in unmanned aerial systems (UAS) – to build a drone that could survive in Venus’ upper atmosphere. This will be no easy task, but if their designs should prove equal to the task, NASA will be awarding the company a lucrative contract for a Venus aerial drone.
In recent years, NASA has taken a renewed interest in Venus, thanks to climate models that have indicated that it (much like Mars) may have also had liquid water on its surface at one time. This would have likely consisted of a shallow ocean that covered much of the planet’s surface roughly 2 billion years ago, before the planet suffered a runaway Greenhouse Effect that left it the hot and hellish world it is today.
In addition, a recent study – which included scientists from NASA’s Ames Research Center and Jet Propulsion Laboratory – indicated that there could be microbial life in Venus’ cloud tops. As such, there is considerable motivation to send aerial platforms to Venus that would be capable of studying Venus’ cloud tops and determining if there are any traces of organic life or indications of the planet’s past surface water there.
As Jack Elston, the co-founded of Black Swift Technologies, explained in an interview with the Daily Camera:
“They’re looking for vehicles to explore just above the cloud layer. The pressure and temperatures are similar to what you’d find on Earth, so it could be a good environment for looking for evidence of life. The winds in the upper atmosphere of Venus are incredibly strong, which creates design challenge.”
To meet this challenge, the company intends to create a drone that will use these strong winds to keep the craft aloft while reducing the amount of electricity it needs. So far, NASA has awarded an initial six-month contract to the company to design a drone and provided specifications on what it needs. This contract included a $125,000 grant by the federal governments’ Small Business Innovation Research program.
This program aims to encourage “domestic small businesses to engage in Federal Research/Research and Development (R/R&D) that has the potential for commercialization.” The company hopes to use some of this grant money to take on more staff and build a drone that NASA would be confident about sending int Venus’ upper atmosphere, where conditions are particularly challenging.
As Elston explained to Universe Today via email, these challenges represent an opportunity for innovation:
“Our project centers around a unique aircraft and method for harvesting energy from Venus’s upper atmosphere that doesn’t require additional sources of energy for propulsion. Our experience working on unmanned aircraft systems that interact with severe convective storms on Earth will hopefully provide a valuable contribution to the ongoing discussion for how best to explore this turbulent environment. Additionally, the work we do will help inform better designs of our own aircraft and should lead to longer observation times and more robust aircraft to observe everything from volcanic plumes to hurricanes.”
At the end of the six month period, Black Swift will present its concept to NASA for approval. “If they like what we’ve come up with, they’ll fund another two-year project to build prototypes,” said Elston. “That second-phase contract is expected to be worth $750,000.”
This is not the first time that Black Swift has partnered with NASA to created unmanned aerial vehicles to study harsh environments. Last year, the company was awarded a second phase contract worth $875,000 to build a drone that could monitor the temperature, gas levels, winds and pressure levels inside the volcanoes of Costa Rica. After a series of test flights, the drone is expected to be deployed to Hawaii, where it will study the geothermal activity occurring there.
All of these missions aim to reach Venus and brave its harsh conditions in order to determine whether or not “Earth’s Sister Planet” was once a more habitable planet, and how it evolved over time to become the hot and hellish place it is today.
NASA’s Opportunity mission can rightly be called the rover that just won’t quit. Originally, this robotic rover was only meant to operate on Mars for 90 Martian days (or sols), which works out to a little over 90 Earth days. However, since it made its landing on January 25th, 2004, it has remained in operation for 14 years, 4 months, and 18 days – exceeding its operating plan by a factor of 50!
However, a few weeks ago, NASA received disturbing news that potentially posed a threat to the “little rover that could”. A Martian storm, which has since grown to occupy an area larger than North America – 18 million km² (7 million mi²) – was blowing in over rover’s position in the Perseverance Valley. Luckily, NASA has since made contact with the rover, which is encouraging sign.
NASA’s Mars Reconnaissance Orbiter first detected the storm on Friday, June 1st, and immediately notified the Opportunity team to begin preparing contingency plans. The storm quickly grew over the next few days and resulted in dust clouds that raised the atmosphere’s opacity, which blocked out most of the sunlight from reaching the surface. This is bad news for the rover since it relies on solar panels for power and to recharge its batteries.
By Wednesday, June 6th, Opportunity’s power levels had dropped significantly and the rover was required to shift to minimal operations. But beyond merely limiting the rover’s operations, a prolonged dust storm also means that the rover might not be able to keep its energy-intensive survival heaters running – which protect its batteries from the extreme cold of Mars’ atmosphere.
The Martian cold is believed to be what resulted in the loss of the Spirit rover in 2010, Opportunity’s counterpart in the Mars Exploration Rover mission. Much like Opportunity, Spirit‘s mission as only meant to last for 90 days, but the rover managed to remain in operation for 2269 days (2208 sols) from start to finish. It’s also important to note that Opportunity has dealt with long-term storms before and emerged unscathed.
Back in 2007, a much larger storm covered the planet, which led to two weeks of minimal operations and no communications. However, the current storm has intensified as of Sunday morning (June 10th), creating a perpetual state of night over the rover’s location in Perseverance Valley and leading to a level of atmospheric opacity that is much worse than the 2007 storm.
Whereas the previous storm had an opacity level (tau) of about 5.5, this new storm has an estimated tau of 10.8. Luckily, NASA engineers received a transmission from the rover on Sunday, which was a positive indication since it proved that the rover still has enough battery charge to communicate with controllers at NASA’s Jet Propulsion Laboratory. This latest transmission also showed that the rover’s temperature had reached about -29 °C (-20 °F).
Full dust storms like this and the one that took place in 2007 are rare, but not surprising. They occur during summer in the southern hemisphere, when sunlight warms dust particles and lifts them higher into the atmosphere, creating more wind. That wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand. While they can begin suddenly, they tend to last on the order of weeks or even months.
A saving grace about these storms is that they limit the extreme temperature swings, and the dust they kick up can also absorb solar radiation, thus raising ambient temperatures around Opportunity. In the coming weeks, engineers at the JPL will continue to monitor the rover’s power levels and ensure that it maintains the proper balance to keep its batteries in working order.
In the meantime, Opportunity’s science operations remain suspended and the Opportunity team has requested additional communications coverage from NASA’s Deep Space Network – the global system of antennas that communicates with all of the agency’s deep space missions. And if there’s one thing Opportunity has proven, it is that it’s capable of enduring!
Fingers crossed the storm subsides as soon as possible and the little rover that could once again emerges unscathed. At this rate, it could have many more years of life left in it!
Our understanding of distant stars has increased dramatically in recent decades. Thanks to improved instruments, scientists are able to see farther and clearer, thus learning more about star systems and the planets that orbit them (aka. extra-solar planets). Unfortunately, it will be some time before we develop the necessary technology to explore these stars up close.
But in the meantime, NASA and the ESA are developing missions that will allow us to explore our own Sun like never before. These missions, NASA’s Parker Solar Probe and the ESA’s (the European Space Agency) Solar Orbiter, will explore closer to the Sun than any previous mission. In so doing, it is hoped that they will resolve decades-old questions about the inner workings of the Sun.
These missions – which will launch in 2018 and 2020, respectively – will also have significant implications for life here on Earth. Not only is sunlight essential to life as we know it, solar flares can pose a major hazard for technology that humanity is becoming increasingly dependent on. This includes radio communications, satellites, power grids and human spaceflight.
And in the coming decades, Low-Earth Orbit (LEO) is expected to become increasingly crowded as commercial space stations and even space tourism become a reality. By improving our understanding of the processes that drive solar flares, we will therefore be able to better predict when they will occur and how they will impact Earth, spacecraft, and infrastructure in LEO.
As Chris St. Cyr, the Solar Orbiter project scientist at NASA’s Goddard Space Flight Center, explained in a recent NASA press release:
“Our goal is to understand how the Sun works and how it affects the space environment to the point of predictability. This is really a curiosity-driven science.”
Both missions will focus on the Sun’s dynamic outer atmosphere, otherwise known as the corona. At present, much of the behavior of this layer of the Sun is unpredictable and not well understood. For instance, there’s the so-called “coronal heating problem”, where the corona of the Sun is so much hotter than the solar surface. Then there is the question of what drives the constant outpouring of solar material (aka. solar wind) to such high speeds.
As Eric Christian, a research scientist on the Parker Solar Probe mission at NASA Goddard, explained:
“Parker Solar Probe and Solar Orbiter employ different sorts of technology, but — as missions — they’ll be complementary. They’ll be taking pictures of the Sun’s corona at the same time, and they’ll be seeing some of the same structures — what’s happening at the poles of the Sun and what those same structures look like at the equator.”
For its mission, the Parker Solar Probe will get closer to the Sun than any spacecraft in history – as close as 6 million km (3.8 million mi) from the surface. This will replace the previous record of 43.432 million km (~27 million mi), which was established by the Helios B probe in 1976. From this position, the Parker Solar Probe will use its four suites of scientific instruments to image the solar wind and study the Sun’s magnetic fields, plasma and energetic particles.
In so doing, the probe will help clarify the true anatomy of the Sun’s outer atmosphere, which will help us to understand why the corona is hotter than the Sun’s surface. Basically, while temperatures in the corona can reach as high as a few million degrees, the solar surface (aka. photosphere), experiences temperatures of around 5538 °C (10,000 °F).
Meanwhile, the Solar Orbiter will come to a distance of about 42 million km (26 million mi) from the Sun, and will assume a highly-tilted orbit that can provide the first-ever direct images of the Sun’s poles. This is another area of the Sun that scientists don’t yet understand very well, and the study of it could provide valuable clues as to what drives the Sun’s constant activity and eruptions.
Both missions will also study solar wind, which is the Sun’s most pervasive influence on the solar system. This steam of magnetized gas fills the inner Solar System, interacting with magnetic fields, atmospheres and even the surfaces of planets. Here on Earth, it is what is responsible for the Aurora Borealis and Australis, and can also play havoc with satellites and electrical systems at times.
Previous missions have led scientists to believe that the corona contributes to the process that accelerates solar wind to such high speeds. As these charged particles leave the Sun and pass through the corona, their speed effectively triples. By the time the solar wind reaches the spacecraft responsible for measuring it – 148 million km (92 million mi) from the Sun – it has plenty of time to mix with other particles from space and lose some of its defining features.
By being parked so close to the Sun, the Parker Solar Probe will able to measure the solar wind just as it forms and leaves the corona, thus providing the most accurate measurements of solar wind ever recorded. From its perspective above the Sun’s poles, the Solar Orbiter will complement the Parker Solar Probe’s study of the solar wind by seeing how the structure and behavior of solar wind varies at different latitudes.
This unique orbit will also allow the Solar Orbiter to study the Sun’s magnetic fields, since some of the Sun’s most interesting magnetic activity is concentrated at the poles. This magnetic field is far-reaching largely because of solar wind, which reaches outwards to create a magnetic bubble known as the heliosphere. Within the heliosphere, solar wind has a profound effect on planetary atmospheres and its presence protects the inner planets from galactic radiation.
In spite of this, it is still not entirely clear how the Sun’s magnetic field is generated or structured deep inside the Sun. But given its position, the Solar Orbiter will be able to study phenomena that could lead to a better understanding of how the Sun’s magnetic field is generated. These include solar flares and coronal mass ejections, which are due to variability caused by the magnetic fields around the poles.
In this way, the Parker Solar Probe and Solar Orbiter are complimentary missions, studying the Sun from different vantage points to help refine our knowledge of the Sun and heliosphere. In the process, they will provide valuable data that could help scientists to tackle long-standing questions about our Sun. This could help expand our knowledge of other star systems and perhaps even answer questions about the origins of life.
As Adam Szabo, a mission scientist for Parker Solar Probe at NASA Goddard, explained:
“There are questions that have been bugging us for a long time. We are trying to decipher what happens near the Sun, and the obvious solution is to just go there. We cannot wait — not just me, but the whole community.”
In time, and with the development of the necessary advanced materials, we might even be able to send probes into the Sun. But until that time, these missions represent the most ambitious and daring efforts to study the Sun to date. As with many other bold initiatives to study our Solar System, their arrival cannot come soon enough!
Volcanic activity on Io was discovered by Voyager 1 imaging scientist Linda Morabito. She spotted a little bump on Io’s limb while analyzing a Voyager image and thought at first it was an undiscovered moon. Moments later she realized that wasn’t possible — it would have been seen by earthbound telescopes long ago. Morabito and the Voyager team soon came to realize they were seeing a volcanic plume rising 190 miles (300 km) off the surface of Io. It was the first time in history that an active volcano had been detected beyond the Earth. For a wonderful account of the discovery, click here.
Today, we know that Io boasts more than 130 active volcanoes with an estimated 400 total, making it the most volcanically active place in the Solar System. Juno used its Jovian Infrared Aurora Mapper (JIRAM) to take spectacular photographs of Io during Perijove 7 last July, when we were all totally absorbed by close up images of Jupiter’s Great Red Spot.
Juno’s Io looks like it’s on fire. Because JIRAM sees in infrared, a form of light we sense as heat, it picked up the signatures of at least 60 hot spots on the little moon on both the sunlight side (right) and the shadowed half. Like all missions to the planets, Juno’s cameras take pictures in black and white through a variety of color filters. The filtered views are later combined later by computers on the ground to create color pictures. Our featured image of Io was created by amateur astronomer and image processor Roman Tkachenko, who stacked raw images from this data set to create the vibrant view.
Io’s hotter than heck with erupting volcano temperatures as high as 2,400° F (1,300° C). Most of its lavas are made of basalt, a common type of volcanic rock found on Earth, but some flows consist of sulfur and sulfur dioxide, which paints the scabby landscape in unique colors.
This five-frame sequence taken by NASA’s New Horizons spacecraft on March 1, 2007 captures the giant plume from Io’s Tvashtar volcano.
Located more than 400 million miles from the Sun, how does a little orb only a hundred miles larger than our Moon get so hot? Europa and Ganymede are partly to blame. They tug on Io, causing it to revolve around Jupiter in an eccentric orbit that alternates between close and far. Jupiter’s powerful gravity tugs harder on the moon when its closest and less so when it’s farther away. The “tug and release”creates friction inside the satellite, heating and melting its interior. Io releases the pent up heat in the form of volcanoes, hot spots and massive lava flows.
How would you like to take an all-expenses-paid trip to the Sun? NASA is inviting people around the world to submit their names to be placed on a microchip aboard the Parker Solar Probe mission that will launch this summer. As the spacecraft dips into the blazing hot solar corona your name will go along for the ride. To sign up, submit your name and e-mail. After a confirming e-mail, your digital “seat” will be booked. You can even print off a spiffy ticket. Submissions will be accepted until April 27, so come on down!
The Parker Solar Probe is the size of a small car and named for Prof. Eugene Parker, a 90-year-old American astrophysicist who in 1958 discovered the solar wind. It’s the first time that NASA has named a spacecraft after a living person. The Parker probe will launch between July 31 and August 19 but not immediately head for the Sun. Instead it will make a beeline for Venus for the first of seven flybys. Each gravity assist will slow the craft down and reshape its orbit (see below), so it later can pass extremely close to the Sun. The first flyby is slated for late September.
When heading to faraway places, NASA typically will fly by a planet to increase the spacecraft’s speed by robbing energy from its orbital motion. But a probe can also approach a planet on a different trajectory to slow itself down or reconfigure its orbit.
The spacecraft will swing well within the orbit of Mercury and more than seven times closer than any spacecraft has come to the Sun before. When closest at just 3.9 million miles (6.3 million km), it will pass through the Sun’s outer atmosphere called the corona and be subjected to temperatures around 2,500°F (1,377°C). The primary science goals for the mission are to trace how energy and heat move through the solar corona and to explore what accelerates the solar wind as well as solar energetic particles.
The vagaries of the solar wind, a steady flow of particles that “blows” from the Sun’s corona at more than million miles an hour, can touch Earth in beautiful ways as when it energizes the aurora borealis. But it can also damage spacecraft electronics and poorly protected power grids on the ground. That’s why scientists want to know more about how the corona works, in particular why it’s so much hotter than the surface of the Sun — temperatures there are several million degrees.
As you can imagine, it gets really, really hot near the Sun, so you’ve got to take special precautions. To perform its mission, the spacecraft and instruments will be protected from the Sun’s heat by a 4.5-inch-thick carbon-composite shield, which will keep the four instrument suites designed to study magnetic fields, plasma and energetic particles, and take pictures of the solar wind, all at room temperature.
Similar to how the Juno probe makes close passes over Jupiter’s radiation-fraught polar regions and then loops back out to safer ground, the Parker probe will make 24 orbits around the Sun, spending a relatively short amount of face to face time with our star. At closest approach, the spacecraft will be tearing along at about 430,000 mph, fast enough to get from Washington, D.C., to Tokyo in under a minute, and will temporarily become the fastest manmade object. The current speed record is held by Helios-B when it swung around the Sun at 156,600 mph (70 km/sec) on April 17, 1976.
Many of you saw last August’s total solar eclipse and marveled at the beauty of the corona, that luminous spider web of light around Moon’s blackened disk. When closest to the Sun at perihelion the Parker probe will fly to within 9 solar radii (4.5 solar diameters) of its surface. That’s just about where the edge of the furthest visual extent of the corona merged with the blue sky that fine day, and that’s where Parker will be!
Since that time, NASA has been keeping the public apprised of the mission’s progress, mainly by sending back images taken by the spacecraft. The latest image was one of the Earth and Moon, which the spacecraft took using its NavCam 1 imager on January 17th, 2018. As part of an engineering test, this image shows just how far the probe has ventured from Earth.
The image was taken when the spacecraft was at a distance of 63.6 million km (39.5 million mi) from the Earth and Moon. When the camera acquired the image, the spacecraft was moving at a speed of 8.5 km per second (19,000 mph) away from Earth. Earth can be seen in the center of the image as the brightest of the two spots while the smaller, dimmer Moon appears to the right.
Several constellations are also visible in the surrounding space, including the Pleiades cluster in the upper left corner. Hamal, the brightest star in Aries, is also visible in the upper right corner of the image. Meanwhile, the Earth-Moon system is nestled between the five stars that make up the head of Cetus the Whale.
This is merely the latest in a string of photographs that show how far OSIRIS-REx has ventured from Earth. On October 2nd, 2017, the probe’s MapCam instrument took a series of images of the Earth and Moon while the probe was at a distance of 5 million km (3 million mi) – about 13 times the distance between the Earth and the Moon. NASA then created a composite image to create a lovely view of the Earth-Moon system (see below).
On September 22nd, 2017, the probe also snapped a “Blue Marble” image of Earth (seen below) while it was at a distance of just 170,000 km (106,000 mi). The image was captured just a few hours after OSIRIS-REx had completed its critical Earth Gravity Assist (EGA) maneuver, which slung it around the Earth and on its way towards the asteroid Bennu for its scheduled rendezvous in December of 2018.
On both of these occasions, the images were taken by the probe’s MapCam instrument, a medium-range camera designed to capture images of outgassing around Bennu and help map its surface in color. The NavCam 1 instrument, by contrast, is a grayscale imager that is part of Touch-And-Go Camera System (TAGCAMS) navigation camera suite.
The design, construction and testing of this instrument was carried out by Malin Space Science Systems, and Lockheed Martin is responsible for its operation. By the time OSIRIS-REx begins to approach asteroid Bennu in December of 2018, we can expect that the probes cameras will once again be busy.
However, by this time, they will be turned towards its destination. As it nears Bennu, its cameras will need to be calibrated yet again by snapping images of the asteroid on approach. And we, the public, can expect that more beautiful composite images will be shared as a result.
Some truly interesting and ambitious missions have been proposed by NASA and other space agencies for the coming decades. Of these, perhaps the most ambitious include missions to explore the “Ocean Worlds” of the Solar System. Within these bodies, which include Jupiter’s moon Europa and Saturn’s moon Enceladus, scientists have theorized that life could exist in warm-water interior oceans.
By the 2020s and 2030s, robotic missions are expected to reach these worlds and set down on them, sampling ice and exploring their plumes for signs of biomarkers. But according to a new study by an international team of scientists, the surfaces of these moons may have extremely low-density surfaces. In other words, the surface ice of Europa and Enceladus could be too soft to land on.
For the sake of their study, the team sought to explain the unusual negative polarization behavior at low phase angles that has been observed for decades when studying atmosphereless bodies. This polarization behavior is thought to be the result of extremely fine-grained bright particles. To simulate these surfaces, the team used thirteen samples of aluminum oxide powder (Al²O³).
Aluminum oxide is considered to be an excellent analog for regolith found on high aldebo Airless Solar System Bodies (ASSB), which include Europa and Encedalus as well as eucritic asteroids like 44 Nysa and 64 Angelina. The team then subjected these samples to photopolarimetric examinations using the goniometric photopolarimeter at Mt. San Antonio College.
What they found was that the bright grains that make up the surfaces of Europa and Enceladus would measure about a fraction of a micron and have a void space of about 95%. This corresponds to material that is less dense than freshly-fallen snow, which would seem to indicate that these moon’s have very soft surfaces. Naturally, this does not bode well for any missions that would attempt to set down on Europa or Enceladus’ surface.
But as Nelson explained in PSI press release, this is not necessarily bad news, and such fears have been raised before:
“Of course, before the landing of the Luna 2 robotic spacecraft in 1959, there was concern that the Moon might be covered in low density dust into which any future astronauts might sink. However, we must keep in mind that remote visible-wavelength observations of objects like Europa are only probing the outermost microns of the surface.”
So while Europa and Enceladus may have surfaces with a layer of low-density ice particles, it does not rule out that their outer shells are solid. In the end, landers may be forced to contend with nothing more than a thin sheet of snow when setting down on these worlds. What’s more, if these particles are the result of plume activity or action between the interior and the surface, they could hold the very biomarkers the probes are looking for.
Of course, further studies are needed before any robotic landers are sent to bodies like Europa and Enceladus. In the coming years, the James Webb Space Telescope will be conducting studies of these and other moons during its first five months in service. This will include producing maps of the Galilean Moons, revealing things about their thermal and atmospheric structure, and searching their surfaces for signs of plumes.
The data the JWST obtains with its advanced suite of spectroscopic and near-infrared instruments will also provide additional constraints on their surface conditions. And with other missions like the ESA’s proposed Europa Clipper conducting flybys of these moons, there’s no shortage to what we can learn from them.
Beyond being significant to any future missions to ASSBs, the results of this study are also likely to be of value when it comes to the field of terrestrial geo-engineering. Essentially, scientists have suggested that anthropogenic climate change could be mitigated by introducing aluminum oxide into the atmosphere, thus offsetting the radiation absorbed by greenhouse gas emissions in the upper atmosphere. By examining the properties of these grains, this study could help inform future attempts to mitigate climate change.
This study was made possible thanks in part to a contract provided by NASA’s Jet Propulsion Laboratory to the PSI. This contract was issued in support of the NASA Cassini Saturn Orbiter Visual and Infrared Mapping Spectrometer instrument team.
It’s no secret that China’s growth in the past few decades has been reflected in space. In addition to the country’s growing economic power and international influence, it has also made some very impressive strides in terms of its space program. This includes the development of the Long March rocket family, the deployment of their first space station, and the Chinese Lunar Exploration Program (CLEP) – aka. the Chang’e program.
Given all that, one would not be surprised to learn that China has some big plans for 2018. But as the China Aerospace Science and Technology Corporation (CASC) announced last Tuesday (on January 2nd, 2018), they intend to double the number of launches they conducted in 2017. In total, the CASC plans to mount over 40 launches, which will include the Long March 5 returning to flight, the Chang’e 4 mission, and the deployment of multiple satellites.
In 2017, China hoped to conduct around 30 launches, which would consist of the launch of a new Tianzhoui-1 cargo craft to the Tiangong-2 space lab and the deployment of the Chang’e 5 lunar sample return mission. However, the latter mission was postponed after the Long March 5 rocket that would have carried it to space failed during launch. As such, the Chang’e 5 mission is now expected to launch next year.
That failed launch also pushed back the next flight of Long March 5, which had conducted its maiden flight in November of 2016. In the end, China closed the year with 18 launches, which was four less than the national record it set in 2016 – 22 launches. It also came in third behind the United States with 29 launches (all of which were successful) and Russia’s 20 launches (19 of which were successful).
Looking to not be left behind again, the CASC hopes to mount 35 launches in 2018. Meanwhile, the China Aerospace Science Industry Corporation (CASIC) – a defense contractor, missile maker and sister company of CASC – will carry out a number of missions through its subsidiary, ExPace. These will include four Kuaizhou-1A rocket launches in one week and the maiden flight of the larger Kuaizhou-11 rocket.
In addition, Landspace Technology – a Beijing-based private aerospace company – is also expected to debut its LandSpace-1 rocket this year. In January of 2017, Landspace signed a contract with Denmark-based satellite manufacturer GOMspace to become the first Chinese company to develop its own commercial rockets that would provide services to the international marketplace.
But of course, the highlights of this year’s launches will be the Long March 5’s return to service, and the launch of the Chang’e 4 mission. Unlike the previous Chang’e missions, Chang’e 4 will be China’s first attempt to mount a lunar mission that involves a soft landing. The mission will consist of a relay orbiter, a lander and a rover, the primary purpose of which will be to explore the geology of the South Pole-Aitken Basin.
For decades, this basin has been a source of fascination for scientists; and in recent years, multiple missions have confirmed the existence of water ice in the region. Determining the extent of the water ice is one of the main focuses of the rover mission component. However, the lander will also to be equipped with an aluminum case filled with insects and plants that will test the effects of lunar gravity on terrestrial organisms.
These studies will play a key role in China’s long-term plans to mount crewed missions to the Moon, and the possible construction of a lunar outpost. In recent years, China has indicated that it may be working with the European Space Agency to create this outpost, which the ESA has described as an “international Moon village” that will be the spiritual successor to the ISS.
The proposed launch of the Long March 5 is also expected to be a major event. As China’s largest and most powerful launch vehicle, this rocket will be responsible for launching heavy satellites, modules of the future Chinese space station, and eventual interplanetary missions. These include crewed missions to Mars, which China hopes to mount between the 2040s and 2060s.
According to the GB times, no details about the Long March 5’s return to flight mission were revealed, but there have apparently been indications that it will involve the large Dongfanghong-5 (DFH-5) satellite bus. In addition, no mentions have been made of when the Long March 5B will begin conducting missions to Low Earth Orbit (LEO), though this remains a possibility for either 2018 or 2019.
Other expected missions of note include the deployment of more than 10 Beidou GNSS satellites – which are basically the Chinese version of GPS satellites – to Medium Earth Orbits (MEOs). A number of other satellites will be sent into orbit, ranging from Earth and ocean observation to weather and telecommunications satellites. All in all, 2018 will be a very busy year for the Chinese space program!
One of the hallmarks of the modern space age is the way in which emerging powers are taking part like never before. This of course includes China, whose presence in space has mirrored their rise in terms of global affairs. At the same time, the Indian Space Research Organization (IRSO), the European Space Agency, JAXA, the Canadian Space Agency, the South African Space Agency, and many others have been making their presence felt as well.
In short, space exploration is no longer the province of two major superpowers. And in the future, when crewed interplanetary missions and (fingers crossed!) the creation of colonies on other planets becomes a reality, it will likely entail a huge degree of international cooperation and public-private partnerships.