Space Station investigation called BCAT-CS studies dynamic forces between
sediment particles that cluster together.
For the study, scientists sent mixtures of quartz and clay particles to the space
station and subjected them to various levels of simulated gravity.
Conducting the experiment in microgravity makes it possible to separate out different forces that act on sediments and look at the function of
Sediment systems of quartz and clay occur many places on Earth, including rivers,
lakes, and oceans, and affect many
activities, from deep-sea hydrocarbon drilling to carbon sequestration.
sediments behave has a range of applications on Earth, including predicting and mitigating erosion, improving water
treatment, modeling the carbon cycle,
sequestering contaminants and more accurately finding deep sea oil
It also may provide insight for future studies of the
geology of new and unexplored planets.
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.
This spectacular image, the first released
using all four of TESS’ cameras, shows the satellite’s full field of view. It
captures parts of a dozen constellations, from Capricornus
(the Sea Goat) to Pictor
(the Painter’s Easel) — though it might be hard to find familiar constellations
among all these stars! The image even includes the Large and Small Magellanic
Clouds, our galaxy’s two largest companion galaxies.
The science community calls this image “first
light,” but don’t let that fool you — TESS has been seeing light since it
launched in April. A first light image like this is released to show off the
first science-quality image taken after a mission starts collecting science
data, highlighting a spacecraft’s capabilities.
After nearly a month in space, the satellite
passed about 5,000 miles from the Moon, whose gravity gave it the boost it needed to get into a special orbit
that will keep it stable and maximize its view of the sky.
During those first few weeks, we also got a
sneak peek of the sky through one of TESS’s four cameras. This test image
captured over 200,000 stars in just two seconds! The spacecraft was pointed
toward the constellation Centaurus when it snapped this picture. The bright
Centauri is visible at the lower left edge, and the edge
of the Coalsack
Nebula is in the right upper corner.
After settling into orbit, scientists ran a
number of checks on TESS, including testing its ability to collect a set of
stable images over a prolonged period of time. TESS not only proved its ability
to perform this task, it also got a surprise! A comet named C/2018 N1 passed through TESS’s cameras
for about 17 hours in July.
The images show a treasure
trove of cosmic curiosities. There are some stars whose
brightness changes over time and asteroids visible as small moving white dots.
You can even see an arc of stray light from Mars, which is located outside the
image, moving across the screen.
Now that TESS has settled into orbit and has
been thoroughly tested, it’s digging into its main mission of finding planets around other stars.
How will it spot something as tiny and faint as a planet trillions of miles
away? The trick is to look at the star!
So far, most
of the exoplanets we’ve found were detected by looking
for tiny dips in the brightness of their host stars. These dips are caused by
the planet passing between us and its star – an event called a transit. Over
its first two years, TESS will stare at 200,000 of the nearest and brightest stars
in the sky to look for transits to identify stars with planets.
TESS will be building on the legacy of NASA’s Kepler spacecraft, which also used
transits to find exoplanets. TESS’s target stars are about 10 times closer than
Kepler’s, so they’ll tend to be brighter. Because they’re closer and brighter,
TESS’s target stars will be ideal candidates for follow-up studies with current
and future observatories.
TESS is challenging over 200,000 of our
stellar neighbors to a staring contest! Who knows what new amazing planets
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.
After traveling for two years and billions of kilometers from Earth, the OSIRIS-REx probe is only a few months away from its destination: the intriguing asteroid Bennu. When it arrives in December, OSIRIS-REx will embark on a nearly two-year investigation of this clump of rock, mapping its terrain and finding a safe and fruitful site from which to collect a sample.
The spacecraft will briefly touch Bennu’s surface around July 2020 to collect at least 60 grams (equal to about 30 sugar packets) of dirt and rocks. It might collect as much as 2,000 grams, which would be the largest sample by far gathered from a space object since the Apollo Moon landings. The spacecraft will then pack the sample into a capsule and travel back to Earth, dropping the capsule into Utah’s west desert in 2023, where scientists will be waiting to collect it.
This years-long quest for knowledge thrusts Bennu into the center of one of the most ambitious space missions ever attempted. But the humble rock is but one of about 780,000 known asteroids in our solar system. So why did scientists pick Bennu for this momentous investigation? Here are 10 reasons:
1. It’s close to Earth
Unlike most other asteroids that circle the Sun in the asteroid belt between Mars and Jupiter, Bennu’s orbit is close in proximity to Earth’s, even crossing it. The asteroid makes its closest approach to Earth every 6 years. It also circles the Sun nearly in the same plane as Earth, which made it somewhat easier to achieve the high-energy task of launching the spacecraft out of Earth’s plane and into Bennu’s. Still, the launch required considerable power, so OSIRIS-REx used Earth’s gravity to boost itself into Bennu’s orbital plane when it passed our planet in September 2017.
2.It’s the right size
Asteroids spin on their axes just like Earth does. Small ones, with diameters of 200 meters or less, often spin very fast, up to a few revolutions per minute. This rapid spinning makes it difficult for a spacecraft to match an asteroid’s velocity in order to touch down and collect samples. Even worse, the quick spinning has flung loose rocks and soil, material known as “regolith” — the stuff OSIRIS-REx is looking to collect — off the surfaces of small asteroids. Bennu’s size, in contrast, makes it approachable and rich in regolith. It has a diameter of 492 meters, which is a bit larger than the height of the Empire State Building in New York City, and rotating once every 4.3 hours.
3. It’s really old
Bennu is a leftover fragment from the tumultuous formation of the solar system. Some of the mineral fragments inside Bennu could be older than the solar system. These microscopic grains of dust could be the same ones that spewed from dying stars and eventually coalesced to make the Sun and its planets nearly 4.6 billion years ago. But pieces of asteroids, called meteorites, have been falling to Earth’s surface since the planet formed. So why don’t scientists just study those old space rocks? Because astronomers can’t tell (with very few exceptions) what kind of objects these meteorites came from, which is important context. Furthermore, these stones, that survive the violent, fiery decent to our planet’s surface, get contaminated when they land in the dirt, sand, or snow. Some even get hammered by the elements, like rain and snow, for hundreds or thousands of years. Such events change the chemistry of meteorites, obscuring their ancient records.
4.It’s well preserved
Bennu, on the other hand, is a time capsule from the early solar system, having been preserved in the vacuum of space. Although scientists think it broke off a larger asteroid in the asteroid belt in a catastrophic collision between about 1 and 2 billion years ago, and hurtled through space until it got locked into an orbit near Earth’s, they don’t expect that these events significantly altered it.
5. It might contain clues to the origin of life
Analyzing a sample from Bennu will help planetary scientists better understand the role asteroids may have played in delivering life-forming compounds to Earth. We know from having studied Bennu through Earth- and space-based telescopes that it is a carbonaceous, or carbon-rich, asteroid. Carbon is the hinge upon which organic molecules hang. Bennu is likely rich in organic molecules, which are made of chains of carbon bonded with atoms of oxygen, hydrogen, and other elements in a chemical recipe that makes all known living things. Besides carbon, Bennu also might have another component important to life: water, which is trapped in the minerals that make up the asteroid.
6. It contains valuable materials
Besides teaching us about our cosmic past, exploring Bennu close-up will help humans plan for the future. Asteroids are rich in natural resources, such as iron and aluminum, and precious metals, such as platinum. For this reason, some companies, and even countries, are building technologies that will one day allow us to extract those materials. More importantly, asteroids like Bennu are key to future, deep-space travel. If humans can learn how to extract the abundant hydrogen and oxygen from the water locked up in an asteroid’s minerals, they could make rocket fuel. Thus, asteroids could one day serve as fuel stations for robotic or human missions to Mars and beyond. Learning how to maneuver around an object like Bennu, and about its chemical and physical properties, will help future prospectors.
7. It will help us better understand other asteroids
Astronomers have studied Bennu from Earth since it was discovered in 1999. As a result, they think they know a lot about the asteroid’s physical and chemical properties. Their knowledge is based not only on looking at the asteroid, but also studying meteorites found on Earth, and filling in gaps in observable knowledge with predictions derived from theoretical models. Thanks to the detailed information that will be gleaned from OSIRIS-REx, scientists now will be able to check whether their predictions about Bennu are correct. This work will help verify or refine telescopic observations and models that attempt to reveal the nature of other asteroids in our solar system.
8. It will help us better understand a quirky solar force …
Astronomers have calculated that Bennu’s orbit has drifted about 280 meters (0.18 miles) per year toward the Sun since it was discovered. This could be because of a phenomenon called the Yarkovsky effect, a process whereby sunlight warms one side of a small, dark asteroid and then radiates as heat off the asteroid as it rotates. The heat energy thrusts an asteroid either away from the Sun, if it has a prograde spin like Earth, which means it spins in the same direction as its orbit, or toward the Sun in the case of Bennu, which spins in the opposite direction of its orbit. OSIRIS-REx will measure the Yarkovsky effect from close-up to help scientists predict the movement of Bennu and other asteroids. Already, measurements of how this force impacted Bennu over time have revealed that it likely pushed it to our corner of the solar system from the asteroid belt.
9. … and to keep asteroids at bay
One reason scientists are eager to predict the directions asteroids are drifting is to know when they’re coming too-close-for-comfort to Earth. By taking the Yarkovsky effect into account, they’ve estimated that Bennu could pass closer to Earth than the Moon is in 2135, and possibly even closer between 2175 and 2195. Although Bennu is unlikely to hit Earth at that time, our descendants can use the data from OSIRIS-REx to determine how best to deflect any threatening asteroids that are found, perhaps even by using the Yarkovsky effect to their advantage.
10. It’s a gift that will keep on giving
Samples of Bennu will return to Earth on September 24, 2023. OSIRIS-REx scientists will study a quarter of the regolith. The rest will be made available to scientists around the globe, and also saved for those not yet born, using techniques not yet invented, to answer questions not yet asked.
Read the web version of this week’s “Solar System: 10 Things to Know” article HERE.
To most of us, dust is an annoyance. Something to be cleaned up, washed off or wiped away. But these tiny particles that float about and settle on surfaces play an important role in a variety of processes on Earth and across the solar system. So put away that feather duster for a few moments, as we share with you 10 things to know about dust.
1. “Dust” Doesn’t Mean Dirty, it Means Tiny
Not all of what we call “dust” is made of the same stuff. Dust in your home generally consists of things like particles of sand and soil, pollen, dander (dead skin cells), pet hair, furniture fibers and cosmetics. But in space, dust can refer to any sort of fine particles smaller than a grain of sand. Dust is most commonly bits of rock or carbon-rich, soot-like grains, but in the outer solar system, far from the Sun’s warmth, it’s also common to find tiny grains of ice as well. Galaxies, including our Milky Way, contain giant clouds of fine dust that are light years across – the ingredients for future generations of planetary systems like ours.
2. Some Are Big, Some Are Small (and Big Ones Tend to Fall)
Dust grains come in a range of sizes, which affects their properties. Particles can be extremely tiny, from only a few tens of nanometers (mere billionths of a meter) wide, to nearly a millimeter wide. As you might expect, smaller dust grains are more easily lifted and pushed around, be it by winds or magnetic, electrical and gravitational forces. Even the gentle pressure of sunlight is enough to move smaller dust particles in space. Bigger particles tend to be heavier, and they settle out more easily under the influence of gravity.
For example, on Earth, powerful winds can whip up large amounts of dust into the atmosphere. While the smaller grains can be transported over great distances, the heavier particles generally sink back to the ground near their source. On Saturn’s moon Enceladus, jets of icy dust particles spray hundreds of miles up from the surface; the bigger particles are lofted only a few tens of miles (or kilometers) and fall back to the ground, while the finest particles escape the moon’s gravity and go into orbit around Saturn to create the planet’s E ring.
3. It’s EVERYWHERE
Generally speaking, the space between the planets is pretty empty, but not completely so. Particles cast off by comets and ground up bits of asteroids are found throughout the solar system. Take any volume of space half a mile (1 kilometer) on a side, and you’d average a few micron-sized particles (grains the thickness of a red blood cell).
Dust in the solar system was a lot more abundant in the past. There was a huge amount of it present as the planets began to coalesce out of the disk of material that formed the Sun. In fact, motes of dust gently sticking together were likely some of the earliest seeds of the planet-building process. But where did all that dust come from, originally? Some of it comes from stars like our Sun, which blow off their outer layers in their later years. But lots of it also comes from exploding stars, which blast huge amounts of dust and gas into space when they go boom.
4. From a Certain Point of View
Dust is easier to see from certain viewing angles. Tiny particles scatter light depending on how big their grains are. Larger particles tend to scatter light back in the direction from which it came, while very tiny particles tend to scatter light forward, more or less in the direction it was already going. Because of this property, structures like planetary rings made of the finest dusty particles are best viewed with the Sun illuminating them from behind. For example, Jupiter’s rings were only discovered after the Voyager 1 spacecraft passed by the planet, where it could look back and see them backlit by the Sun. You can see the same effect looking through a dusty windshield at sunset; when you face toward the Sun, the dust becomes much more apparent.
5. Dust Storms Are Common on Mars
Local dust storms occur frequently on Mars, and occasionally grow or merge to form regional systems, particularly during the southern spring and summer, when Mars is closest to the Sun. On rare occasions, regional storms produce a dust haze that encircles the planet and obscures surface features beneath. A few of these events may become truly global storms, such as one in 1971 that greeted the first spacecraft to orbit Mars, our Mariner 9. In mid-2018, a global dust storm enshrouded Mars, hiding much of the Red Planet’s surface from view and threatening the continued operation of our uber long-lived Opportunity rover. We’ve also seen global dust storms in 1977, 1982, 1994, 2001 and 2007.
Dust storms will likely present challenges for future astronauts on the Red Planet. Although the force of the wind on Mars is not as strong as portrayed in an early scene in the movie “The Martian,” dust lofted during storms could affect electronics and health, as well as the availability of solar energy.
6. Dust From the Sahara Goes Global
Earth’s largest, hottest desert is connected to its largest tropical rain forest by dust. The Sahara Desert is a near-uninterrupted brown band of sand and scrub across the northern third of Africa. The Amazon rain forest is a dense green mass of humid jungle that covers northeast South America. But after strong winds sweep across the Sahara, a dusty cloud rises in the air, stretches between the continents, and ties together the desert and the jungle.
This trans-continental journey of dust is important because of what is in the dust. Specifically, the dust picked up from the Bodélé Depression in Chad – an ancient lake bed where minerals composed of dead microorganisms are loaded with phosphorus. Phosphorus is an essential nutrient for plant proteins and growth, which the nutrient-poor Amazon rain forest depends on in order to flourish.
7. Rings and Things
The rings of the giant planets contain a variety of different dusty materials. Jupiter’s rings are made of fine rock dust. Saturn’s rings are mostly pure water ice, with a sprinkling of other materials. (Side note about Saturn’s rings: While most of the particles are boulder-sized, there’s also lots of fine dust, and some of the fainter rings are mostly dust with few or no large particles.) Dust in the rings of Uranus and Neptune is made of dark, sooty material, probably rich in carbon.
Over time, dust gets removed from ring systems due to a variety of processes. For example, some of the dust falls into the planet’s atmosphere, while some gets swept up by the planets’ magnetic fields, and other dust settles onto the surfaces of the moons and other ring particles. Larger particles eventually form new moons or get ground down and mixed with incoming material. This means rings can change a lot over time, so understanding how the tiniest ring particles are being moved about has bearing on the history, origins and future of the rings.
8. Moon Dust is Clingy and Might Make You Sick
So, dust is kind of a thing on the Moon. When the Apollo astronauts visited the Moon, they found that lunar dust quickly coated their spacesuits and was difficult to remove. It was quite abrasive, causing wear on their spacesuit fabrics, seals and faceplates. It also clogged mechanisms like the joints in spacesuit limbs, and interfered with fasteners like zippers and Velcro. The astronauts also noted that it had a distinctive, pungent odor, not unlike gunpowder, and it was an eye and lung irritant.
Many of these properties apparently can be explained by the fact that lunar dust particles are quite rough and jagged. While dust particles on Earth get tumbled and ground by the wind into smoother shapes, this sort of weathering doesn’t happen so much on the Moon. The roughness of Moon dust grains makes it very easy for them to cling to surfaces and scratch them up. It also means they’re not the sort of thing you would want to inhale, as their jagged edges could damage delicate tissues in the lung.
9. Dust is What Makes Comets So Pretty
Most comets are basically clods of dust, rock and ice. They spend most of their time far from the Sun, out in the refrigerated depths of the outer solar system, where they’re peacefully dormant. But when their orbits carry them closer to the Sun – that is, roughly inside the orbit of Jupiter – comets wake up. In response to warming temperatures, the ices on and near their surfaces begin to turn into gases, expanding outward and away from the comet, and creating focused jets of material in places. Dust gets carried away by this rapidly expanding gas, creating a fuzzy cloud around the comet’s nucleus called a coma. Some of the dust also is drawn out into a long trail – the comet’s tail.
10. We’re Not the Only Ones Who’re So Dusty
Dust in our solar system is continually replenished by comets whizzing past the Sun and the occasional asteroid collision, and it’s always being moved about, thanks to a variety of factors like the gravity of the planets and even the pressure of sunlight. Some of it even gets ejected from our solar system altogether.
With telescopes, we also observe dusty debris disks around many other stars. As in our own system, the dust in such disks should evolve over time, settling on planetary surfaces or being ejected, and this means the dust must be replenished in those star systems as well. So studying the dust in our planetary environs can tell us about other systems, and vice versa. Grains of dust from other planetary systems also pass through our neighborhood – a few spacecraft have actually captured and analyzed some them – offering us a tangible way to study material from other stars.
Read the full version of ‘Solar System: 10 Things to Know’ article HERE.
Tonight, Australians, Africans, Europeans, Asians and South Americans will have the opportunity to see the longest lunar eclipse of the century. Sorry North America.
Lunar eclipses occur about 2-4 times per year, when the Moon passes into the Earth’s shadow. In order to see a lunar eclipse, you must be on the night side of the Earth, facing the Moon, when the Earth passes in between the Moon and the Sun. Need help visualizing this? Here you go:
What’s the difference between a solar eclipse and a lunar eclipse?
An easy way to remember the difference between a solar eclipse and a lunar eclipse is that the word ‘eclipse’ refers to the object that is being obscured. During a solar eclipse, the Moon blocks the Sun from view. During a lunar eclipse, the Earth’s shadow obscures the Moon.
Why does the Moon turn red?
You may have heard the term ‘Blood Moon’ for a lunar eclipse. When the Moon passes into the Earth’s shadow, it turns red. This happens for the exact same reason that our sunrises and sunsets here on Earth are brilliant shades of pinks and oranges. During a lunar eclipse, the only light reaching the Moon passes through the Earth’s atmosphere. The bluer, shorter wavelength light scatters and the longer wavelength red light passes through and makes it to the Moon.
What science can we learn from a lunar eclipse?
“During a lunar eclipse, the temperature swing is so dramatic that it’s as if the surface of the Moon goes from being in an oven to being in a freezer in just a few hours,” said Noah Petro, project scientist for our Lunar Reconnaissance Orbiter, or LRO, at our Goddard Space Flight Center in Greenbelt, Maryland.
The Diviner team from LRO measures temperature changes on the Moon through their instrument on the spacecraft as well as through a thermal camera on Earth. How quickly or slowly the lunar surface loses heat helps scientists determine characteristics of lunar material, including its composition and physical properties.
When is the next lunar eclipse?
North Americans, don’t worry. If skies are clear, you can see the next lunar eclipse on January 21, 2019. The eclipse will be visible to North Americans, South Americans, and most of Africa and Europe.
July’s night skies feature Mars opposition on the 27th, when Mars, Earth, and the Sun all line up, and Mars’ closest approach to Earth since 2003 on the 31st.
If you’ve been sky watching for 15 years or more, then you’ll remember August 2003, when Mars approached closer to Earth than it had for thousands of years.
It was a very small percentage closer, but not so much that it was as big as the moon as some claimed.
Astronomy clubs everywhere had long lines of people looking through their telescopes at the red planet, and they will again this month!
If you are new to stargazing, this month and next will be a great time to check out Mars.
Through a telescope, you should be able to make out some of the light and dark features, and sometimes polar ice. Right now, though, a huge Martian dust storm is obscuring many features, and less planetary detail is visible.
July 27th is Mars opposition, when Mars, Earth, and the Sun all line up, with Earth directly in the middle.
A few days later on July 31st is Mars’ closest approach. That’s when Mars and Earth are nearest to each other in their orbits around the Sun. Although there will be a lot of news focusing on one or the other of these two dates, Mars will be visible for many months.
By the end of July, Mars will be visible at sunset.
But the best time to view it is several hours after sunset, when Mars will appear higher in the sky.
Mars will still be visible after July and August, but each month it will shrink in apparent size as it travels farther from Earth in its orbit around the Sun.
On July 27th a total lunar eclipse will be visible in Australia, Asia, Africa, Europe and South America.
For those viewers, Mars will be right next to the eclipsing moon!
Next month will feature August’s summer Perseids. It’s not too soon to plan a dark sky getaway for the most popular meteor shower of the year!
When our next Mars rover lands on the Red Planet in
2021, it will deliver a groundbreaking technology demonstration: the
first helicopter to ever fly on a planetary body other than Earth. This
Mars Helicopter will demonstrate the first controlled, powered,
sustained flight on another world. It could also pave the way for future
missions that guide rovers and gather science data and images at
locations previously inaccessible on Mars. This exciting new technology
could change the way we explore Mars.
1. Its body is small, but its blades are mighty.
One of the biggest engineering challenges is getting the
Mars Helicopter’s blades just right. They need to push enough air
downward to receive an upward force that allows for thrust and
controlled flight — a big concern on a planet where the atmosphere is
only one percent as dense as Earth’s. “No helicopter has flown in those
flight conditions – equivalent to 100,000 feet (30,000 meters) on
Earth,” said Bob Balaram, chief engineer for the project at our Jet
2. It has to fly in really thin Martian air.
To compensate for Mars’ thin atmosphere, the blades must
spin much faster than on an Earth helicopter, and the blade size
relative to the weight of the helicopter has to be larger too. The Mars
Helicopter’s rotors measure 4 feet wide (about 1.2 meters) long, tip to
tip. At 2,800 rotations per minute, it will spin about 10 times faster
than an Earth helicopter.
At the same time, the blades shouldn’t flap around too much, as
the helicopter’s design team discovered during testing. Their solution:
make the blades more rigid. “Our blades are much stiffer than any
terrestrial helicopter’s would need to be,” Balaram said.
The body, meanwhile, is tiny — about the size of a softball. In
total, the helicopter will weigh just under 4 pounds (1.8 kilograms).
3. It will make up to five flights on Mars.
Over a 30-day period on Mars, the helicopter will attempt
up to five flights, each time going farther than the last. The
helicopter will fly up to 90 seconds at a time, at heights of up to 10
to 15 feet (3 to 5 meters). Engineers will learn a lot about flying a
helicopter on Mars with each flight, since it’s never been done before!
4. The Mars Helicopter team has already completed groundbreaking tests.
Because a helicopter has never visited Mars before, the
Mars Helicopter team has worked hard to figure out how to predict the
helicopter’s performance on the Red Planet. “We had to invent how to do
planetary helicopter testing on Earth,” said Joe Melko, deputy chief
engineer of Mars Helicopter, based at JPL.
The team, led by JPL and including members from JPL,
AeroVironment Inc., Ames Research Center, and Langley Research
Center, has designed, built and tested a series of test vehicles.
In 2016, the team flew a full-scale prototype test model
of the helicopter in the 25-foot (7.6-meter) space simulator at JPL. The
chamber simulated the low pressure of the Martian atmosphere. More
recently, in 2018, the team built a fully autonomous helicopter designed
to operate on Mars, and successfully flew it in the 25-foot chamber in
Mars-like atmospheric density.
Engineers have also exercised the rotors of a test
helicopter in a cold chamber to simulate the low temperatures of Mars at
night. In addition, they have taken design steps to deal with Mars-like
radiation conditions. They have also tested the helicopter’s landing
gear on Mars-like terrain. More tests are coming to see how it performs
with Mars-like winds and other conditions.
5. The camera is as good as your cell phone camera.
The helicopter’s first priority is successfully flying on
Mars, so engineering information takes priority. An added bonus is its
camera. The Mars Helicopter has the ability to take color photos with a
13-megapixel camera — the same type commonly found in smart phones
today. Engineers will attempt to take plenty of good pictures.
6. It’s battery-powered, but the battery is rechargeable.
The helicopter requires 360 watts of power for each
second it hovers in the Martian atmosphere – equivalent to the power
required by six regular lightbulbs. But it isn’t out of luck when its
lithium-ion batteries run dry. A solar array on the helicopter will
recharge the batteries, making it a self-sufficient system as long as
there is adequate sunlight. Most of the energy will be used to keep the
helicopter warm, since nighttime temperatures on Mars plummet to around
minus 130 degrees Fahrenheit (minus 90 Celsius). During daytime flights,
temperatures may rise to a much warmer minus 13 to minus 58 degrees
Fahrenheit to (minus 25 to minus 50 degrees Celsius) — still chilly by
Earth standards. The solar panel makes an average of 3 watts of power
continuously during a 12-hour Martian day.
7. The helicopter will be carried to Mars under the belly of the rover.
Somewhere between 60 to 90 Martian days (or sols) after
the Mars 2020 rover lands, the helicopter will be deployed from the
underside of the rover. Mars Helicopter Delivery System on the rover
will rotate the helicopter down from the rover and release it onto the
ground. The rover will then drive away to a safe distance.
8. The helicopter will talk to the rover.
The Mars 2020 rover will act as a telecommunication
relay, receiving commands from engineers back on Earth and relaying them
to the helicopter. The helicopter will then send images and information
about its own performance to the rover, which will send them back to
Earth. The rover will also take measurements of wind and atmospheric
data to help flight controllers on Earth.
9. It has to fly by itself, with some help.
Radio signals take time to travel to Mars — between four
and 21 minutes, depending on where Earth and Mars are in their orbits —
so instantaneous communication with the helicopter will be impossible.
That means flight controllers can’t use a joystick to fly it in real
time, like a video game. Instead, they need to send commands to the
helicopter in advance, and the little flying robot will follow through.
Autonomous systems will allow the helicopter to look at the ground,
analyze the terrain to look how fast it’s moving, and land on its own.
10. It could pave the way for future missions.
A future Mars helicopter could scout points of interest,
help scientists and engineers select new locations and plan driving
routes for a rover. Larger standalone helicopters could carry science
payloads to investigate multiple sites at Mars. Future helicopters could
also be used to fly to places on Mars that rovers cannot reach, such as
cliffs or walls of craters. They could even assist with human
exploration one day. Says Balaram: “Someday, if we send astronauts,
these could be the eyes of the astronauts across Mars.”
Read the full version of this week’s ‘10 Things to Know’ article on the web HERE.