After seven years of studying the radiation around Earth, the Van Allen Probes spacecraft have retired.
Originally slated for a two-year mission, these two spacecraft studied Earth's radiation belts — giant, donut-shaped clouds of particles surrounding Earth — for nearly seven years. The mission team used the last of their propellant this year to place the spacecraft into a lower orbit that will eventually decay, allowing the Van Allen Probes to re-enter and burn up in Earth's atmosphere.
Earth's radiation belts exist because energized charged particles from the Sun and other sources in space become trapped in our planet's huge magnetic field, creating vast regions around Earth that teem with radiation. This is one of the harshest environments in space — and the Van Allen Probes survived more than three times longer than planned orbiting through this intense region.
The shape, size and intensity of the radiation belts change, meaning that satellites — like those used for telecommunications and GPS — can be bombarded with a sudden influx of radiation. The Van Allen Probes shed new light on what invisible forces drive these changes — like waves of charged particles and electromagnetic fields driven by the Sun, called space weather.
Here are a few scientific highlights from the Van Allen Probes — from the early days of the mission to earlier this year:
The Van Allen belts were first discovered in 1958, and for decades, scientists thought there were only two concentric belts. But, days after the Van Allen Probes launched, scientists discovered that during times of intense solar activity, a third belt can form.
The belts are composed of charged particles and electromagnetic fields and can be energized by different types of plasma waves. One type, called electrostatic double layers, appear as short blips of enhanced electric field. During one observing period, Probe B saw 7,000 such blips repeatedly pass over the spacecraft in a single minute!
During big space weather storms, which are ultimately caused by activity on the Sun, ions — electrically charged atoms or molecules — can be pushed deep into Earth’s magnetosphere. These particles carry electromagnetic currents that circle around the planet and can dramatically distort Earth’s magnetic field.
Across space, fluctuating electric and magnetic fields can create what are known as plasma waves. These waves intensify during space weather storms and can accelerate particles to incredible speeds. The Van Allen Probes found that one type of plasma wave known as hiss can contribute greatly to the loss of electrons from the belts.
The Van Allen belts are composed of electrons and ions with a range of energies. In 2015, research from the Van Allen Probes found that, unlike the outer belt, there were no electrons with energies greater than a million electron volts in the inner belt.
Plasma waves known as whistler chorus waves are also common in our near-Earth environment. These waves can travel parallel or at an angle to the local magnetic field. The Van Allen Probes demonstrated the two types of waves cannot be present simultaneously, resulting in greater radiation belt particle scattering in certain areas.
Very low frequency chorus waves, another variety of plasma waves, can pump up the energy of electrons to millions of electronvolts. During storm conditions, the Van Allen Probes found these waves can hugely increase the energy of particles in the belts in just a few hours.
Scientists often use computer simulation models to understand the physics behind certain phenomena. A model simulating particles in the Van Allen belts helped scientists understand how particles can be lost, replenished and trapped by Earth’s magnetic field.
The Van Allen Probes observed several cases of extremely energetic ions speeding toward Earth. Research found that these ions’ acceleration was connected to their electric charge and not to their mass.
The Sun emits faster and slower gusts of charged particles called the solar wind. Since the Sun rotates, these gusts — the fast wind — reach Earth periodically. Changes in these gusts cause the extent of the region of cold ionized gas around Earth — the plasmasphere — to shrink. Data from the Van Allen Probes showed that such changes in the plasmasphere fluctuated at the same rate as the solar rotation — every 27 days.
Though the mission has ended, scientists will use data from the Van Allen Probes for years to come. See the latest Van Allen Probes science at nasa.gov/vanallen.
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Our leadership hit the road to visit our commercial partners Lockheed Martin, Sierra Nevada Corp. and Ball Aerospace in Colorado. They were able to check the status of flight hardware, mission operations and even test virtual reality simulations that help these companies build spacecraft parts.
Let’s take a look at all the cool technology they got to see…
Lockheed Martin is the prime contractor building our Orion crew vehicle, the only spacecraft designed to take humans into deep space farther than they’ve ever gone before.
Acting NASA Deputy Administrator Lesa Roe and Acting NASA Administrator Robert Lightfoot are seen inside the CHIL…the Collaborative Human Immersive Laboratory at Lockheed Martin Space Systems in Littleton, Colo. Lockheed Martin’s CHIL enables collaboration between spacecraft design and manufacturing teams before physically producing hardware.
Cool shades! The ability to visualize engineering designs in virtual reality offers tremendous savings in time and money compared to using physical prototypes. Technicians can practice how to assemble and install components, the shop floor can validate tooling and work platform designs, and engineers can visualize performance characteristics like thermal, stress and aerodynamics, just like they are looking at the real thing.
This heat shield, which was used as a test article for the Mars Curiosity Rover, will now be used as the flight heat shield for the Mars 2020 rover mission.
Fun fact: Lockheed Martin has built every Mars heat shield and aeroshell for us since the Viking missions in 1976.
Here you can see Lockheed Martin’s Mission Support Area. Engineers in this room support six of our robotic planetary spacecraft: Mars Odyssey, Mars Reconnaissance Orbiter, MAVEN, Juno, OSIRIS-REx and Spitzer, which recently revealed the first known system of seven Earth-size planets around a single star, TRAPPIST-1. They work with NASA centers and the mission science teams to develop and send commands and monitor the health of the spacecraft.
See all the pictures from the Lockheed Martin visit HERE.
Next, Lightfoot and Roe went to Sierra Nevada Corporation in Louisville, Colo. to get an update about its Dream Chaser vehicle. This spacecraft will take cargo to and from the International Space Station as part of our commercial cargo program.
Here, Sierra Nevada Corporation’s Vice President of Space Exploration Systems Steve Lindsey (who is also a former test pilot and astronaut!) speaks with Lightfoot and Roe about the Dream Chaser Space System simulator.
Lightfoot climbed inside the Dream Chaser simulator where he “flew” the crew version of the spacecraft to a safe landing. This mock-up facility enables approach-and-landing simulations as well as other real-life situations.
See all the images from the Sierra Nevada visit HERE.
Lightfoot and Roe went over to Ball Aerospace to tour its facility. Ball is another one of our commercial aerospace partners and helps builds instruments that are on NASA spacecraft throughout the universe, including the Hubble Space Telescope and the New Horizons mission to Pluto. Ball designed and built the advanced optical technology and lightweight mirror system that will enable the James Webb Space Telescope to look 13.5 billion years back in time.
Looking into the clean room at Ball Aerospace’s facility in Boulder, Colo., the team can see the Ozone Mapping Profiler Suite. These sensors are used on spacecraft to track ozone measurements.
Here, the group stands in front of a thermal vacuum chamber used to test satellite optics. The Operation Land Imager-2 is being built for Landsat 9, a collaboration between NASA and the U.S. Geological Survey that will continue the Landsat Program’s 40-year data record monitoring the Earth’s landscapes from space.
See all the pictures from the Ball Aerospace visit HERE.
We recently marked a decade since a new era began in commercial spaceflight development for low-Earth orbit transportation. We inked agreements in 2006 to develop rockets and spacecraft capable of carrying cargo such as experiments and supplies to and from the International Space Station. Learn more about commercial space HERE.
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Is it safe to look at the eclipse if it isn't fully covered by the sun? Say 75%
Not without proper eye wear. There will still be too much light that could burn your eyes. But you can have a ton of fun viewing the Sun using a https://eclipse.aas.org/eye-safety/projection. In fact, there is a sunspot that is now on the Sun that you should be able to see using this indirect method!
The universe is full of dazzling sights, but there’s an eerie side of space, too. Nestled between the stars, shadowy figures lurk unseen. The entire galaxy could even be considered a graveyard, full of long-dead stars. And it’s not just the Milky Way – the whole universe is a bit like one giant haunted house! Our Nancy Grace Roman Space Telescope will illuminate all kinds of spine-chilling cosmic mysteries when it launches in 2027, but for now settle in for some true, scary space stories.
One of the first signs that things are about to get creepy in a scary movie is when the lights start to flicker. That happens all the time in space, too! But instead of being a sinister omen, it can help us find planets circling other stars.
Roman will stare toward the heart of our galaxy and watch to see when pairs of stars appear to align in the sky. When that happens, the nearer star – and orbiting planets – can lens light from the farther star, creating a brief brightening. That’s because every massive object warps the fabric of space-time, changing the path light takes when it passes close by. Roman could find around 1,000 planets using this technique, which is called microlensing.
The mission will also see little flickers when planets cross in front of their host star as they orbit and temporarily dim the light we receive from the star. Roman could find an additional 100,000 planets this way!
Roman is going to be one of the best ghost hunters in the galaxy! Since microlensing relies on an object’s gravity, not its light, it can find all kinds of invisible specters drifting through the Milky Way. That includes rogue planets, which roam the galaxy alone instead of orbiting a star…
…and solo stellar-mass black holes, which we can usually only find when they have a visible companion, like a star. Astronomers think there should be 100 million of these black holes in our galaxy.
Black holes aren’t the only dead stars hiding in the sky. When stars that aren’t quite massive enough to form black holes run out of fuel, they blast away their outer layers and become neutron stars. These stellar cores are the densest material we can directly observe. One sugar cube of neutron star material would weigh about 1 billion tons (or 1 trillion kilograms) on Earth! Roman will be able to detect when these extreme objects collide.
Smaller stars like our Sun have less dramatic fates. After they run out of fuel, they swell up and shrug off their outer layers until only a small, hot core called a white dwarf remains. Those outer layers may be recycled into later generations of stars and planets. Roman will explore regions where new stars are bursting to life, possibly containing the remnants of such dead stars.
If we zoom out far enough, the structure of space looks like a giant cobweb! The cosmic web is the large-scale backbone of the universe, made up mainly of a mysterious substance known as dark matter and laced with gas, upon which galaxies are built. Roman will find precise distances for more than 10 million galaxies to map the structure of the cosmos, helping astronomers figure out why the expansion of the universe is speeding up.
Learn more about the exciting science this mission will investigate on Twitter and Facebook.
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How does it feel to take a walk in space?
It’s Friday…which seems like a great excuse to take a look at some awesome images from space.
First, let’s start with our home planet: Earth.
This view of the entire sunlit side of Earth was taken from one million miles away…yes, one MILLION! Our EPIC camera on the Deep Space Climate Observatory captured this image in July 2015 and the picture was generated by combining three separate images to create a photographic-quality image.
Next, let’s venture out 4,000 light-years from Earth.
This image, taken by the Hubble Space Telescope, is not only stunning…but shows the colorful “last hurrah” of a star like our sun. This star is ending its life by casting off its outer layers of gas, which formed a cocoon around the star’s remaining core. Our sun will eventually burn out and shroud itself with stellar debris…but not for another 5 billion years.
The material expelled by the star glows with different colors depending on its composition, its density and how close it is to the hot central star. Blue samples helium; blue-green oxygen, and red nitrogen and hydrogen.
Want to see some rocks on Mars?
Here’s an image of the layered geologic past of Mars revealed in stunning detail. This color image was returned by our Curiosity Mars rover, which is currently “roving” around the Red Planet, exploring the “Murray Buttes” region.
In this region, Curiosity is investigating how and when the habitable ancient conditions known from the mission’s earlier findings evolved into conditions drier and less favorable for life.
Did you know there are people currently living and working in space?
Right now, three people from three different countries are living and working 250 miles above Earth on the International Space Station. While there, they are performing important experiments that will help us back here on Earth, and with future exploration to deep space.
This image, taken by NASA astronaut Kate Rubins shows the stunning moonrise over Earth from the perspective of the space station.
Lastly, let’s venture over to someplace REALLY hot…our sun.
The sun is the center of our solar system, and makes up 99.8% of the mass of the entire solar system…so it’s pretty huge. Since the sun is a star, it does not have a solid surface, but is a ball of gas held together by its own gravity. The temperature at the sun’s core is about 27 million degrees Fahrenheit (15 million degrees Celsius)…so HOT!
This awesome visualization appears to show the sun spinning, as if stuck on a pinwheel. It is actually the spacecraft, SDO, that did the spinning though. Engineers instructed our Solar Dynamics Observatory (SDO) to roll 360 degrees on one axis, during this seven-hour maneuver, the spacecraft took an image every 12 seconds.
This maneuver happens twice a year to help SDO’s imager instrument to take precise measurements of the solar limb (the outer edge of the sun as seen by SDO).
Thanks for spacing out with us...you may now resume your Friday.
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A human journey to Mars, at first glance, offers an inexhaustible amount of complexities. To bring a mission to the Red Planet from fiction to fact, NASA’s Human Research Program has organized some of the hazards astronauts will encounter on a continual basis into five classifications.
The variance of gravity fields that astronauts will encounter on a mission to Mars is the fourth hazard.
On Mars, astronauts would need to live and work in three-eighths of Earth’s gravitational pull for up to two years. Additionally, on the six-month trek between the planets, explorers will experience total weightlessness.
Besides Mars and deep space there is a third gravity field that must be considered. When astronauts finally return home they will need to readapt many of the systems in their bodies to Earth’s gravity.
To further complicate the problem, when astronauts transition from one gravity field to another, it’s usually quite an intense experience. Blasting off from the surface of a planet or a hurdling descent through an atmosphere is many times the force of gravity.
Research is being conducted to ensure that astronauts stay healthy before, during and after their mission. Specifically researchers study astronauts’ vision, fine motor skills, fluid distribution, exercise protocols and response to pharmaceuticals.
Exploration to the Moon and Mars will expose astronauts to five known hazards of spaceflight, including gravity. To learn more, and find out what NASA’s Human Research Program is doing to protect humans in space, check out the "Hazards of Human Spaceflight" website. Or, check out this week’s episode of “Houston We Have a Podcast,” in which host Gary Jordan further dives into the threat of gravity with Peter Norsk, Senior Research Director/ Element Scientist at the Johnson Space Center.
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This 45 day mission – which began May 5, 2018 and ends today, June 18 – will help our researchers learn how isolation and close quarters affect individual and group behavior. This study at our Johnson Space Center prepares us for long duration space missions, like a trip to an asteroid or even to Mars.
The Human Research Exploration Analog (HERA) that the crew members will be living in is one compact, science-making house. But unlike in a normal house, these inhabitants won’t go outside for 45 days. Their communication with the rest of planet Earth will also be very limited, and they won’t have any access to internet. So no checking social media, kids!
The only people they will talk with regularly are mission control and each other.
The HERA XVII crew is made up of 2 men and 2 women, selected from the Johnson Space Center Test Subject Screening (TSS) pool. The crew member selection process is based on a number of criteria, including criteria similar to what is used for astronaut selection. The four would-be astronauts are:
William Daniels
Chiemi Heil
Eleanor Morgan
Michael Pecaut
What will they be doing?
The crew are going on a simulated journey to an asteroid, a 715-day journey that we compress into 45 days. They will fly their simulated exploration vehicle around the asteroid once they arrive, conducting several site surveys before 2 of the crew members will participate in a series of virtual reality spacewalks.
They will also be participating in a suite of research investigations and will also engage in a wide range of operational and science activities, such as growing and analyzing plants and brine shrimp, maintaining and “operating” an important life support system, exercising on a stationary bicycle or using free weights, and sharpening their skills with a robotic arm simulation.
During the whole mission, they will consume food produced by the Johnson Space Center Food Lab – the same food that the astronauts enjoy on the International Space Station – which means that it needs to be rehydrated or warmed in a warming oven.
This simulation means that even when communicating with mission control, there will be a delay on all communications ranging from 1 to 5 minutes each way.
A few other details:
The crew follows a timeline that is similar to one used for the space station crew.
They work 16 hours a day, Monday through Friday. This includes time for daily planning, conferences, meals and exercise.
Mission: May 5 - June 18, 2018
But beware! While we do all we can to avoid crises during missions, crews need to be able to respond in the event of an emergency. The HERA crew will conduct a couple of emergency scenario simulations, including one that will require them to respond to a decrease in cabin pressure, potentially finding and repairing a leak in their spacecraft.
Throughout the mission, researchers will gather information about living in confinement, teamwork, team cohesion, mood, performance and overall well-being. The crew members will be tracked by numerous devices that each capture different types of data.
Learn more about the HERA mission HERE.
Explore the HERA habitat via 360-degree videos HERE.
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How did your perspective on Earth & humanity change from space?
What would the future look like if people were regularly visiting to other planets and moons? These travel posters give a glimpse into that imaginative future. Take a look and choose your destination:
Our Voyager mission took advantage of a once-every-175-year alignment of the outer planets for a grand tour of the solar system. The twin spacecraft revealed details about Jupiter, Saturn, Uranus and Neptune – using each planet’s gravity to send them on to the next destination.
Our Mars Exploration Program seeks to understand whether Mars was, is, or can be a habitable world. This poster imagines a future day when we have achieved our vision of human exploration of the Red Planet and takes a nostalgic look back at the great imagined milestones of Mars exploration that will someday be celebrated as “historic sites.”
There’s no place like home. Warm, wet and with an atmosphere that’s just right, Earth is the only place we know of with life – and lots of it. Our Earth science missions monitor our home planet and how it’s changing so it can continue to provide a safe haven as we reach deeper into the cosmos.
The rare science opportunity of planetary transits has long inspired bold voyages to exotic vantage points – journeys such as James Cook’s trek to the South Pacific to watch Venus and Mercury cross the face of the sun in 1769. Spacecraft now allow us the luxury to study these cosmic crossings at times of our choosing from unique locales across our solar system.
Ceres is the closest dwarf planet to the sun. It is the largest object in the main asteroid belt between Mars and Jupiter, with an equatorial diameter of about 965 kilometers. After being studied with telescopes for more than two centuries, Ceres became the first dwarf planet to be explored by a spacecraft, when our Dawn probe arrived in orbit in March 2015. Dawn’s ongoing detailed observations are revealing intriguing insights into the nature of this mysterious world of ice and rock.
The Jovian cloudscape boasts the most spectacular light show in the solar system, with northern and southern lights to dazzle even the most jaded space traveler. Jupiter’s auroras are hundreds of times more powerful than Earth’s, and they form a glowing ring around each pole that’s bigger than our home planet.
The discovery of Enceladus’ icy jets and their role in creating Saturn’s E-ring is one of the top findings of the Cassini mission to Saturn. Further Cassini discoveries revealed strong evidence of a global ocean and the first signs of potential hydrothermal activity beyond Earth – making this tiny Saturnian moon one of the leading locations in the search for possible life beyond Earth.
Frigid and alien, yet similar to our own planet billions of years ago, Saturn’s largest moon, Titan has a thick atmosphere, organic-rich chemistry and surface shaped by rivers and lakes of liquid ethane and methane. Our Cassini orbiter was designed to peer through Titan’s perpetual haze and unravel the mysteries of this planet-like moon.
Astonishing geology and the potential to host the conditions for simple life making Jupiter’s moon Europa a fascinating destination for future exploration. Beneath its icy surface, Europa is believed to conceal a global ocean of salty liquid water twice the volume of Earth’s oceans. Tugging and flexing from Jupiter’s gravity generates enough heat to keep the ocean from freezing.
You can download free poster size images of these thumbnails here: http://www.jpl.nasa.gov/visions-of-the-future/
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Astronauts onboard the International Space station are typically active for at least 9 1/2 hours per day doing science, exercising and maintaining systems. Excluding scheduled time for sleep and lunch, astronauts have only 4 hours of free time during the work week, and that includes time for meals and general hygiene.
Even with a loaded calendar, the few who have such an opportunity to live in the microgravity environment find ways to make the most of this experience. Here are just a few of their favorite things about living in space:
Flying
One of the most self-explanatory (and most fun!) aspects of living in space for the astronauts is “flying”. In space there is no up or down, so there is no floor or ceiling. There are rails throughout the space station that astronauts use to push themselves among the modules.
Eating
Astronauts actually describe the food on the space station as quite tasty! In part, that’s because they have a large role in choosing their own meals. Over time though, a lot of astronauts experience desensitized taste buds from the shifting fluid to their head. Toward the end of their expedition, spicy foods tend to be their favorites because of this phenomenon.
Drinking
Liquid behaves very differently in space than it does on Earth. Astronauts cannot simply pour a cup of coffee into a mug. Without gravity, it would stick to the walls of the cup and would be very difficult to sip. Most of the time, astronauts fill a bag with liquid and use a special straw with a clamp to keep the contents from flying out.
Playing Games
The space station crew occasionally gets downtime which they can spend however they please. Sometimes they watch a movie, read a book or take photos of Earth from the Cupola windows. Other times they invent games to play with each other, and each crew tends to come up with new games. Sometimes it can be hitting a target, flying from one end of the station to the other fastest or playing zero-gravity sports.
Going Out For A Walk
Preparing and executing a spacewalk can take around 8 to 12 hours, and can be a jam-packed schedule. Spacewalkers have to be focused on the task at hand and sticking to the timeline. That said, they can still catch a spare moment to see the Earth 250 miles below. Many astronauts describe that view from a spacewalk as one of the most beautiful sights in their lives.
Watch Commander Scott Kelly and Flight Engineer Kjell Lindgren perform a spacewalk on Oct. 28 at 8:15 a.m. EDT live on NASA Television.
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