Asteroid Terms: Explained

Asteroid Terms: Explained

There are interesting asteroid characters in our solar system, including an asteroid that has its own moon and even one that is shaped like a dog bone! Our OSIRIS-REx mission launches at 7:05 p.m. EDT today and will travel to asteroid Bennu.

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Scientists chose Bennu as the target of the OSIRIS-REx mission because of its composition, size and proximity to Earth. Bennu is a rare B-type asteroid (primitive and carbon-rich), which is expected to have organic compounds and water-bearing minerals like clays.

Our OSIRIS-REx mission will travel to Bennu and bring a small sample back to Earth for study.

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When talking about asteroids, there are some terms scientists use that might not be in your typical vocabulary…but we’ll help with that!

Here are a few terms you should know:

Orbital Eccentricity: This number describes the shape of an asteroid’s orbit by how elliptical it is. For asteroids in orbit around the sun, eccentricity is a number between 0 and 1, with 0 being a perfectly circular orbit and 0.99 being a highly elliptical orbit.

Inclination: The angle, in degrees, of how tilted an asteroid’s orbit is compared to another plane of reference, usually the plane of the Earth’s orbit around the sun.

Orbital Period: The number of days it takes for an asteroid to revolve once around the sun. For example, the Earth’s orbital period is 365 days.

Perihelion Distance: The distance between an asteroid and the sun when the asteroid is closest to the sun.

Aphelion Distance: The distance between the asteroid and the sun when the asteroid is farthest away from the sun.

Astronomical unit: A distance unit commonly used to describe orbits of objects around the sun. The distance from the Earth to the sun is one astronomical unit, or 1 AU, equivalent to about 93 million miles or 150 million kilometers.

Diameter: A measure of the size of an asteroid. It is the length of a line from a point on the surface, through the center of the asteroid, extending out to the opposite surface. Irregularly shaped asteroids may have different diameters depending on which direction they are measured.

Rotation Period: The time it takes for an asteroid to complete one revolution around its axis of rotation. For example, the rotation period of the Earth is approximately 24 hours, or 1 day.

Spectral Type: The classification of an asteroid, based on a measurement of the light reflected by the asteroid. 

Asteroid Terms: Explained

Watch live launch coverage of OSIRIS-REx to asteroid Bennu starting at 5:30 p.m, on NASA TV: http://www.nasa.gov/nasatv 

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More Posts from Nasa and Others

9 years ago

Eight Things to Know About Our Flying Observatory

Our flying observatory, called SOFIA, is the world’s largest airborne observatory. It is a partnership with the German Aerospace Center (DLR). SOFIA studies the life cycle of stars, planets (including Pluto’s atmosphere), how interstellar dust can contribute to planet formation, analyzes the area around black holes, and identifies complex molecules in space.

1. A Telescope in an Airplane

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SOFIA stands for the Stratospheric Observatory for Infrared Astronomy. It is a Boeing 747SP aircraft that carries a 100-inch telescope to observe the universe while flying between 38,000 and 45,000 feet – the layer of Earth’s atmosphere called the stratosphere.

2. The Short Aircraft Means Long Flights

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SP stands for “special performance.” The plane is 47 feet shorter than a standard 747, so it’s lighter and can fly greater distances.  Each observing flight lasts 10-12 hours.

3. It Flies with A Hole in the Side of the Plane…

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The telescope is behind a door that opens when SOFIA reaches altitude so astronomers on board can study the universe. The kind of light SOFIA observes, infrared, is blocked by almost all materials, so engineers designed the side of the aircraft to direct air up-and-over the open cavity, ensuring a smooth flight.

4. …But the Cabin is Pressurized!

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A wall, called a pressure bulkhead, was added between the telescope and the cabin so the team inside the aircraft stays comfortable and safe. Each flight has pilots, telescope operators, scientists, flight planners and mission crew aboard.

5. This Telescope Has to Fly

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Water vapor in Earth’s atmosphere blocks infrared light from reaching the ground. Flying at more than 39,000 feet puts SOFIA above more than 99% of this vapor, allowing astronomers to study infrared light coming from space. The airborne observatory can carry heavier, more powerful instruments than space-based observatories because it is not limited by launch weight restrictions and solar power.

6. Studying the Invisible Universe

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Humans cannot see what is beyond the rainbow of visible light. However, many interesting astronomical processes happen in the clouds of dust and gas that often surround the objects SOFIA studies, like newly forming stars. Infrared light can pass through these clouds, allowing astronomers to study what is happening inside these areas.

7. The German Telescope

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The telescope was built our partner, the German Aerospace Center, DLR. It is made of a glass-ceramic material called Zerodur that does not change shape when exposed to extremely cold temperatures. The telescope has a honeycomb design, which reduces the weight by 80%, from 8,700 lb to 1,764 lb. (Note that the honeycomb design was only visible before the reflective aluminum coating was applied to the mirror’s surface).

8. ZigZag Flights with a Purpose

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The telescope can move up and down, between 20-60 degrees above the horizon. But it can only move significantly left and right by turning the whole aircraft. Each new direction of the flight means astronomers are studying a new celestial object. SOFIA’s flight planners carefully map where the plane needs to fly to best observe each object planned for that night.

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7 years ago

Exploring an Asteroid Without Leaving Earth

This 45 day mission – which begins Feb. 1, 2018 – 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.

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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.

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The HERA XVI 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:

Kent Kalogera

Jennifer Yen

Erin Hayward

Gregory Sachs

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.

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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. 

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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: February 1, 2018 - March 19, 2018

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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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5 years ago
NASA Spotlight: Astronaut Jonny Kim

NASA Spotlight: Astronaut Jonny Kim

Dr. Jonny Kim was selected by NASA to join the 2017 Astronaut Candidate Class. He reported for duty in August 2017 and having completed the initial astronaut candidate training is now eligible for mission assignments to the International Space Station, the Moon and eventually Mars. A U.S. Navy SEAL, Kim completed more than 100 combat operations. Kim was commissioned as a naval officer through an enlisted-to-officer program and earned his degree in mathematics at the University of San Diego and a doctorate of medicine at Harvard Medical School. Born and raised in Los Angeles, California to Korean-American immigrants, he enjoys spending time with his family, outdoor activities, academic and professional mentoring, strength training and lifelong learning. 

Dr. Kim took some time from his job as a NASA astronaut to answer questions about his life and career! Enjoy: 

Why did you apply to be an astronaut?

For many reasons. I think that humans are natural explorers. There is a calling in all of us to explore the unknown, push the boundaries and redefine what is possible. I’m drawn to the physical and mental challenges of space exploration and the teamwork required to complete such an objective. And finally, the opportunity to do something good for our country, for humanity, and to inspire the next generation of thinkers, leaders, explorers and scientists.

What was your favorite memory from astronaut training?

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I’m a big believer that people can grow stronger bonds with each other when they succeed through shared hardship. And I think that developing relationships with one another is one of the best ways to forge successful team skills to be successful in any endeavor. With that context, I can tell you that my favorite memory from astronaut training was traversing the deep canyon slots of the Utah Canyon Lands for almost 2 weeks with my classmates. We hiked trails, climbed canyons, swam through deep, dark, cold and murky waters and forged through uncertainty, all while being together. This shared hardship was not only fun, but it helped us grow closer to one another. It’s one of the fondest memories I have when I think about my amazing classmates, and through that shared hardship, I know I can count on any one of my fellow astronauts when the going gets tough.

If you could play any song during launch, what would it be?

Don’t Stop Believin’ by Journey.

What advice would you give to your younger self?

I would tell myself to always follow your passion, never stature or money, because following a life of passion is long-term, sustainable and usually helps others. Be accountable for your mistakes and failures, and maintain the humility to learn from those mistakes and failures. And finally, I would caution myself that all worthwhile goals are difficult to obtain, but with the right attitude and hard work, you can accomplish anything.

How did your time as a Navy Seal impact your astronaut training?

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Being a Naval Special Warfare Operator taught me that humans are capable of accomplishing ten times what their bodies and mind tell them. I learned there are no limits in life, and the biggest setback one can have is a poor attitude. I learned the value of strong leadership and accountability. I also learned the meaning of sacrifice, hardship, teamwork, love and compassion. All these traits helped me to develop the hard and soft skills required to be an astronaut.

How do we prepare medically for long duration missions? What tools, resources, medications do we anticipate needing, and how do we figure that out?

This is a great question and the answer is evolving. The way we answer this question is by being thoughtful and consulting the medical communities to weigh the pros and cons of every single decision we make regarding this. Mass plays an important factor, so we have to be mindful of everything we bring and how we train for it.

Who was the first person you called after being selected to be an astronaut?

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It would have been my wife but she was with me when I heard the news. The first person I called was my mom.

What is one item from home that you would bring to space?

A picture of my wife and kids.

What does it mean to you to be part of the Artemis generation of astronauts?

NASA Spotlight: Astronaut Jonny Kim

It means that I have a duty and obligation to serve humanity’s best interests. To explore the unknown, push boundaries and redefine what’s possible. It means I have an immense opportunity to serve as an example and inspiration to our next generation of leaders and explorers. It also means there is a hard road ahead, and when the mission calls for us, we will be ready.

What are three personal items, besides photos of family and friends, that you would bring with you on your first spaceflight?

An automatic watch, because the engineering behind a timepiece is a beautiful thing. An American flag, because I proudly believe and uphold the principles and ideals our country stands for. And finally, a nice journal that I can put handwritten thoughts on.

Thank you for your time, and good luck on your first spaceflight assignment!

Follow Jonny Kim on Twitter and Instagram to keep up with his life as NASA astronaut. 

It’s not too late to APPLY to #BeAnAstronaut! Applications close TOMORROW, March 31. 

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5 years ago

What’s aboard SpaceX’s Dragon?

On Dec 5. 2019, a SpaceX Falcon 9 rocket blasted off from Cape Canaveral Air Force Station in Florida carrying a Dragon cargo capsule filled with dozens of scientific experiments. Those experiments look at everything from malting barley in microgravity to the spread of fire.

What’s Aboard SpaceX’s Dragon?

Not only are the experiments helping us better understand life in space, they also are giving us a better picture of our planet and benefiting humanity back on Earth. 

📸 A Better Picture of Earth 🌏

Every material on the Earth’s surface – soil, rocks, vegetation, snow, ice and human-made objects – reflects a unique spectrum of light. The Hyperspectral Imager Suite (HISUI) takes advantage of this to identify specific materials in an image. It could be useful for tasks such as resource exploration and applications in agriculture, forestry and other environmental areas.

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🌱 Malting Barley in Microgravity 🌱

Many studies of plants in space focus on how they grow in microgravity. The Malting ABI Voyager Barley Seeds in Microgravity experiment is looking at a different aspect of plants in space: the malting process. Malting converts starches from grain into various sugars that can be used for brewing, distilling and food production. The study compares malt produced in space and on the ground for genetic and structural changes, and aims to identify ways to adapt it for nutritional use on spaceflights.

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🛰️ A First for Mexico 🛰️

AztechSat-1, the first satellite built by students in Mexico for launch from the space station, is smaller than a shoebox but represents a big step for its builders. Students from a multidisciplinary team at Universidad Popular Autónoma del Estado de Puebla in Puebla, Mexico, built the CubeSat. This investigation demonstrates communication within a satellite network in low-Earth orbit. Such communication could reduce the need for ground stations, lowering the cost and increasing the number of data downloads possible for satellite applications.

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🚀 Checking for Leaks 🚀

Nobody wants a spacecraft to spring a leak – but if it happens, the best thing you can do is locate and fix it, fast. That’s why we launched the first Robotic External Leak Locator (RELL) in 2015. Operators can use RELL to quickly detect leaks outside of station and help engineers formulate a plan to resolve an issue. On this latest commercial resupply mission, we launched the Robotic Tool Stowage (RiTS), a docking station that allows the RELL units to be stored on the outside of space station, making it quicker and simpler to deploy the instruments.

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🔥 The Spread of Fire 🔥

Understanding how fire spreads in space is crucial for the safety of future astronauts and for controlling fire here on Earth. The Confined Combustion investigation examines the behavior of flame as it spreads in differently-shaped spaces in microgravity. Studying flames in microgravity gives researchers a chance to look at the underlying physics and basic principles of combustion by removing gravity from the equation.

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💪 Staying Strong 💪

Here on Earth you might be told to drink milk to grow up with strong bones, but in space, you need a bit more than that. Astronauts in space have to exercise for hours a day to prevent substantial bone and muscle loss. A new experiment, Rodent Research-19, is seeing if there is another way to prevent the loss by targeting signaling pathways in your body at the molecular level. The results could also support treatments for a wide range of conditions that cause muscle and bone loss back here on Earth.

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Want to learn about more investigations heading to the space station (or even ones currently under way)? Make sure to follow @ISS_Research on Twitter and Space Station Research and Technology News on Facebook. 

If you want to see the International Space Station with your own eyes, check out Spot the Station to see it pass over your town.

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9 years ago

Five Orion Technologies That Will Help Us Get Home From Mars

Orion is a key piece of NASA’s journey to Mars. The spacecraft, which was first tested in space last year, will enable crew to travel to deep space on the journey to the Red Planet and bring astronauts home safely. It’s a critical technology we’ll use to help NASA test, demonstrate and hone the skills and capabilities we need to operate farther and farther away from Earth.

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Environmental Control and Life Support Systems

Water. Air. A temperate environment. A bathroom. These are some of the things astronauts need to survive the long journey back to Earth from Mars. NASA has developed an environmental control and life support system on the International Space Station and is designing such a system for Orion. The system can recycle carbon dioxide and make it back into useable air and process urine to make it into potable water, for example. Right now on the space station, engineers and astronauts are testing a filtering system for efficiency and reliability on long-duration missions. The investigation uses an amine-based chemical compound combined with the vacuum of space to filter and renew cabin air for breathing. When astronauts travel home from Mars, they won’t be able to count on the arrival of spare parts or extra supplies if something breaks or gets depleted, so engineers are hard at work developing reliable and robust technologies to keep crews alive and healthy in space.

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Radiation protection

Astronauts traveling to and from Mars will be far away from the protective shield of Earth’s atmosphere and magnetic field, and their spacecraft and its systems will need to be able to protect against the full spectrum of space radiation. NASA is working now to develop protective methods.  

Orion will use items already on board to protect the crew and create a temporary shelter in the aft bay of the spacecraft, which is the inside portion closest to the heat shield. This location minimizes the amount of equipment to move around while maximizing the amount of material that can be placed between the crew and the outside environment. The items that will be used include supplies, equipment and launch and re-entry seats as well as water and food. By using the items already on board, the astronauts benefit from additional shielding without adding to Orion’s mass.

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Power and Propulsion

A spacecraft needs power and propulsion in space to refine its trajectory during the trip back to Earth. Orion will include a service module capable of helping the spacecraft make any necessary mid-course corrections. A service module provides power, heat rejection, in-space propulsion and water and air for crews, and NASA is working with ESA (European Space Agency) to provide Orion’s service module for its next mission in a partnership that will also bring international cooperation on the journey to Mars. The service module will provide propulsion, batteries and solar arrays to generate power and contain all the air, nitrogen and water for crews.

The ESA-provided element brings together new technology and lightweight materials while also taking advantage of spaceflight-proven hardware. For example, ESA is modeling several key components – like the solar arrays – from technology developed for its Automated Transfer Vehicle-series of cargo vessels, which delivered thousands of pounds of supplies to the space station during five missions between 2008 and 2015. NASA is providing ESA one of the Orbital Maneuvering System pods that allowed space shuttles to move in space to be upgraded and integrated into the service module.

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Heat shield

When an uncrewed Orion was tested in space in 2014, the heat shield withstood temperatures of about 4,000 degrees Fahrenheit, or about twice as hot as molten lava. That heat was generated when the spacecraft, traveling at about 20,000 mph back toward our planet, made its way through Earth’s atmosphere, which acts as a braking mechanism to cause friction and slow down a returning spacecraft. Its speed was about 80 percent of what Orion will experience when it comes back from missions near the moon and will need to be even more robust for missions where return speeds, and therefore reentry temperatures, are higher.

Orion’s heat shield is built around a titanium skeleton and carbon fiber skin that provide structural support. A honeycomb structure fits over the skin with thousands of cells that are filled with a material called Avcoat. That layer is 1.6 inches at its thickest and erodes as Orion travels through Earth’s atmosphere.

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Parachutes

A spacecraft bringing crews back to Earth after a long trip to Mars will need a parachute system to help it slow down from its high-speed reentry through the atmosphere to a relatively slow speed for splashdown in the ocean. While Earth’s atmosphere will initially slow Orion down from thousands of miles per hour to about 325 mph, its 11 parachutes will deploy in precise sequence to further slow the capsule’s descent. There are three forward bay cover parachutes that pull a protective cover off the top of the capsule, two drogue parachutes that deploy to stabilize the spacecraft, and three pilot parachutes that are used to pull out Orion’s three orange and white main parachutes that are charged with slowing the spacecraft to its final landing speed. The main parachutes are so big that the three of them together nearly cover an entire football field.

Engineers are currently building the Orion spacecraft that will launch on the world’s most powerful rocket, the Space Launch System, and will enable astronauts to travel farther into space than ever before on the journey to Mars.

Visit NASA on the Web for more information about Orion and NASA’s journey to Mars. http://www.nasa.gov/orion 

8 years ago

7 Things You Need to Know About Small Satellites

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1. Small satellites is the umbrella term for describing any satellite that is the size of an economy-sized washing machine all the way down to a CubeSat, which you can hold in your hand.

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2. CubeSats come in multiple sizes defined by the U, which stands for unit. Making it the Unit unit. 1U CubeSats are cubes 4 inches (10 cm) on a side, weighing as little as 4 pounds. A 3U CubeSat is three 1Us hooked together, resembling a flying loaf of bread. A 6U CubeSat is two 3Us joined at the hip, like a flying cereal box. These are the three most common configurations.

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Photo courtesy of the University of Michigan 

3. CubeSats were developed by researchers at California Polytechnic State University and Stanford University who wanted a standardized format to make launching them into space easier and to be small enough for students to get involved in designing, building and launching a satellite.

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4. Small satellites often hitch a ride to space with another mission. If there’s room on the rocket of a larger mission, they’re in. CubeSats in particular deploy from a p-pod – poly-picosatellite orbital deployer – tucked on the underside of the upper stage of the rocket near the engine bell.

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5. Small sats test technology at lower costs. Their small size and the relatively short amount of time it takes to design and build a small satellite means that if we want to test a new sensor component or a new way of making an observation from space, we can do so without being in the hole if it doesn’t work out. There’s no environment on Earth than can adequately recreate space, so sometimes the only way to know if new ideas work is to send them up and see.

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6. Small sats force us to think of new ways to approach old problems. With a satellite the size of a loaf of bread, a cereal box, or a microwave oven, we don’t have a lot of room for the science instrument or power to run it. That means thinking outside the box. In addition to new and creative designs that include tape measures, customized camera lenses, and other off-the-shelf parts, we have to think of new ways of gathering all the data we need. One thing we’re trying out is flying small sat constellations – a bunch of the same kind of satellite flying in formation. Individually, each small sat sees a small slice of Earth below. Put them together and we start to see the big picture.

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7. Small sats won’t replace big satellites. Size does matter when it comes to power, data storage, and how precise your satellite instrument is. Small satellites come with trade-offs that often mean coarser image resolution and shorter life-spans than their bigger sister satellites. However, small sat data can complement data collected by big satellites by covering more ground, by passing over more frequently, by flying in more dangerous orbits that big satellites avoid, and by continuing data records if there’s a malfunction or a wait between major satellite missions. Together they give us a more complete view of our changing planet.

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3 years ago

New Sun Science Stamps from the U.S. Postal Service

To start off the summer, the U.S. Postal Service issued a set of stamps showcasing views of the Sun from our Solar Dynamics Observatory!

New Sun Science Stamps From The U.S. Postal Service

Since its launch in 2010, the Solar Dynamics Observatory (or SDO) has kept up a near-constant watch on the Sun from its vantage point in orbit around Earth. SDO watches the Sun in more than 10 different types of light, including some that are absorbed by Earth’s atmosphere so can only be seen from space. These different types of light allow scientists to study different parts of the Sun – from its surface to its atmosphere – and better understand the solar activity that can affect our technology on Earth and in space.

New Sun Science Stamps From The U.S. Postal Service

The new set of stamps features 10 images from SDO. Most of these images are in extreme ultraviolet light, which is invisible to human eyes.

Let’s explore the science behind some of the stamps!

Coronal hole (May 2016)

New Sun Science Stamps From The U.S. Postal Service

The dark area capping the northern polar region of the Sun is a coronal hole, a magnetically open area on the Sun from which high-speed solar wind escapes into space. Such high-speed solar wind streams can spark magnificent auroral displays on Earth when they collide with our planet’s magnetic field.

Solar flare (August 2011)

New Sun Science Stamps From The U.S. Postal Service

The bright flash on the Sun’s upper right is a powerful solar flare. Solar flares are bursts of light and energy that can disturb the part of Earth’s atmosphere where GPS and radio signals travel.

Active Sun (October 2014)

New Sun Science Stamps From The U.S. Postal Service

This view highlights the many active regions dotting the Sun’s surface. Active regions are areas of intense and complex magnetic fields on the Sun – linked to sunspots – that are prone to erupting with solar flares or explosions of material called coronal mass ejections.

Plasma blast (August 2012)

New Sun Science Stamps From The U.S. Postal Service

These images show a burst of material from the Sun, called a coronal mass ejection. These eruptions of magnetized solar material can create space weather effects on Earth when they collide with our planet’s magnetosphere, or magnetic environment – including aurora, satellite disruptions, and, when extreme, even power outages.

Coronal loops (July 2012)

New Sun Science Stamps From The U.S. Postal Service

These images show evolving coronal loops across the limb and disk of the Sun. Just days after these images were taken, the Sun unleashed a powerful solar flare.

Coronal loops are often found over sunspots and active regions, which are areas of intense and complex magnetic fields on the Sun.

Sunspots (October 2014)

New Sun Science Stamps From The U.S. Postal Service

This view in visible light – the type of light we can see – shows a cluster of sunspots near the center of the Sun. Sunspots appear dark because they are relatively cool compared to surrounding material, a consequence of the way their extremely dense magnetic field prevents heated material from rising to the solar surface.

For more Sun science, follow NASA Sun on Twitter, on Facebook, or on the web.

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7 years ago

Cassini Spacecraft: Top Discoveries

Our Cassini spacecraft has been exploring Saturn, its stunning rings and its strange and beautiful moons for more than a decade.

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Having expended almost every bit of the rocket propellant it carried to Saturn, operators are deliberately plunging Cassini into the planet to ensure Saturn’s moons will remain pristine for future exploration – in particular, the ice-covered, ocean-bearing moon Enceladus, but also Titan, with its intriguing pre-biotic chemistry.

Let’s take a look back at some of Cassini’s top discoveries:  

Titan

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Under its shroud of haze, Saturn’s planet-sized moon Titan hides dunes, mountains of water ice and rivers and seas of liquid methane. Of the hundreds of moons in our solar system, Titan is the only one with a dense atmosphere and large liquid reservoirs on its surface, making it in some ways more like a terrestrial planet.

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Both Earth and Titan have nitrogen-dominated atmospheres – over 95% nitrogen in Titan’s case. However, unlike Earth, Titan has very little oxygen; the rest of the atmosphere is mostly methane and traced amounts of other gases, including ethane.

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There are three large seas, all located close to the moon’s north pole, surrounded by numerous smaller lakes in the northern hemisphere. Just one large lake has been found in the southern hemisphere.

Enceladus

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The moon Enceladus conceals a global ocean of salty liquid water beneath its icy surface. Some of that water even shoots out into space, creating an immense plume!

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For decades, scientists didn’t know why Enceladus was the brightest world in the solar system, or how it related to Saturn’s E ring. Cassini found that both the fresh coating on its surface, and icy material in the E ring originate from vents connected to a global subsurface saltwater ocean that might host hydrothermal vents.

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With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist.

Iapetus

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Saturn’s two-toned moon Iapetus gets its odd coloring from reddish dust in its orbital path that is swept up and lands on the leading face of the moon.

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The most unique, and perhaps most remarkable feature discovered on Iapetus in Cassini images is a topographic ridge that coincides almost exactly with the geographic equator. The physical origin of the ridge has yet to be explained...

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It is not yet year whether the ridge is a mountain belt that has folded upward, or an extensional crack in the surface through which material from inside Iapetus erupted onto the surface and accumulated locally.

Saturn’s Rings

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Saturn’s rings are made of countless particles of ice and dust, which Saturn’s moons push and tug, creating gaps and waves.

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Scientists have never before studied the size, temperature, composition and distribution of Saturn’s rings from Saturn obit. Cassini has captured extraordinary ring-moon interactions, observed the lowest ring-temperature ever recorded at Saturn, discovered that the moon Enceladus is the source for Saturn’s E ring, and viewed the rings at equinox when sunlight strikes the rings edge-on, revealing never-before-seen ring features and details.

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Cassini also studied features in Saturn’s rings called “spokes,” which can be longer than the diameter of Earth. Scientists think they’re made of thin icy particles that are lifted by an electrostatic charge and only last a few hours.  

Auroras

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The powerful magnetic field that permeates Saturn is strange because it lines up with the planet’s poles. But just like Earth’s field, it all creates shimmering auroras.

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Auroras on Saturn occur in a process similar to Earth’s northern and southern lights. Particles from the solar wind are channeled by Saturn’s magnetic field toward the planet’s poles, where they interact with electrically charged gas (plasma) in the upper atmosphere and emit light.  

Turbulent Atmosphere

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Saturn’s turbulent atmosphere churns with immense storms and a striking, six-sided jet stream near its north pole.

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Saturn’s north and south poles are also each beautifully (and violently) decorated by a colossal swirling storm. Cassini got an up-close look at the north polar storm and scientists found that the storm’s eye was about 50 times wider than an Earth hurricane’s eye.

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Unlike the Earth hurricanes that are driven by warm ocean waters, Saturn’s polar vortexes aren’t actually hurricanes. They’re hurricane-like though, and even contain lightning. Cassini’s instruments have ‘heard’ lightning ever since entering Saturn orbit in 2004, in the form of radio waves. But it wasn’t until 2009 that Cassini’s cameras captured images of Saturnian lighting for the first time.

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Cassini scientists assembled a short video of it, the first video of lightning discharging on a planet other than Earth.

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Cassini’s adventure will end soon because it’s almost out of fuel. So to avoid possibly ever contaminating moons like Enceladus or Titan, on Sept. 15 it will intentionally dive into Saturn’s atmosphere.

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The spacecraft is expected to lose radio contact with Earth within about one to two minutes after beginning its decent into Saturn’s upper atmosphere. But on the way down, before contact is lost, eight of Cassini’s 12 science instruments will be operating! More details on the spacecraft’s final decent can be found HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com


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9 years ago

Hello, Scott? It’s President Obama.

This afternoon, President Obama spoke by phone with astronaut Scott Kelly to welcome him back to Earth from his record-breaking yearlong mission on the International Space Station. 

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President Obama, above, is seen talking on the phone with Scott Kelly in the Oval Office on March 2, 2016. (Official White House Photo by Pete Souza)

The President thanked Kelly for his service, for sharing his journey with people across the globe through social media, for his participation in important research about what it will take for us to make long journeys in space, and for inspiring a new generation of young people to pursue studies and careers in science, technology, engineering, and mathematics. 

Hello, Scott? It’s President Obama.

The President also noted that Kelly’s year in space would provide critical data to researchers trying to understand how to keep astronauts healthy during long space voyages and fulfill the President’s vision of putting American astronauts on Mars in the 2030s. 

Thanks to Kelly’s work, in addition to that of everyone at NASA and in the U.S. space industry, the President believes the United States will be successful in that journey to Mars and will continue to lead and inspire the world in space exploration.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com


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7 years ago

100 Days in Houston

A lot can happen in 100 days...

At our Johnson Space Center, located in Houston, it has been busy since July 10. Here are six things that have been going on in Houston with our astronauts, the International Space Station and our next great telescope! Take a look:

1. Our James Webb Space Telescope is Spending 100 Days in a Freezing Cold Chamber

Imagine seeing 13.5 billion light-years back in time, watching the birth of the first stars, galaxies evolve and solar systems form…our James Webb Space Telescope will do just that once it launches in 2019.

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Webb will be the premier observatory of the next decade, studying every phase in the cosmic history of our universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems.

On July 10, the Webb telescope entered Johnson Space Center’s historic Chamber A for its final cryogenic test that lasts about 100 days behind a closed giant vault-like door. 

Why did we put Webb in this freezing cold chamber? To ensure it can withstand the harsh environment it will experience in space.

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The telescope has been in a space-like environment in the chamber, tested at cryogenic temperatures. In space, the telescope must operate at extremely cold temperatures so that it can detect infrared light – heat radiation -- from faint, distant objects. 

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To keep the telescope cold while in space, Webb has a sunshield the size of a tennis court, which blocks sunlight (as well as reflected light from the Earth and Moon). This means that the sun-facing side of the observatory is incredibly hot while the telescope-side remains at sub-freezing temperatures.

2. Our 12 new astronaut candidates reported to Houston to start training

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Our newest class of astronaut candidates, which were announced on June 7, reported for training on August 13. These candidates will train for two years on International Space Station systems, space vehicles and Russian language, among many other skills, before being flight-ready. 

3. Our Mission Control Center operated for 2,400 hours

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While astronauts are in space, Mission Control operates around the clock making sure the crew is safe and the International Space Station is functioning properly. This means workers in Mission Control work in three shifts, 7 a.m. – 4 p.m., 3 p.m. – midnight and 11 p.m. – 8 a.m. This includes holidays and weekends. Day or night, Mission Control is up and running.

4. Key Teams at Johnson Space Center Continued Critical Operations During Hurricane Harvey

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Although Johnson Space Center closed during Hurricane Harvey, key team members and critical personnel stayed onsite to ensure crucial operations would continue. Mission Control remained in operation throughout this period, as well as all backup systems required to maintain the James Webb Space Telescope, which is at Johnson for testing, were checked prior to the arrival of the storm, and were ready for use if necessary.

5. Crews on the International Space Station conducted hundreds of science experiments.

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Mission Control at Johnson Space Center supported astronauts on board the International Space Station as they worked their typical schedule in the microgravity environment. Crew members work about 10 hours a day conducting science research that benefits life on Earth as well as prepares us for travel deeper into space. 

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The space station team in Houston supported a rigorous schedule of launches of cargo that included supplies and science materials for the crew living and working in the orbiting laboratory, launched there by our commercial partners. 

6. Two new crews blasted off to space and a record breaking astronaut returned from a stay on space station

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Houston is home to the Astronaut Corps, some of whom end up going out-of-this-world. On July 28, NASA Astronaut Randy Bresnik launched to the International Space Station alongside Italian astronaut Paolo Naspoli and Russian cosmonaut Sergey Ryazanskiy. Joining them at the International Space Station were NASA Astronauts Joe Acaba and Mark Vande Hei who launched September 12 with Russian cosmonaut Alexander Misurkin.

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When NASA Astronaut Peggy Whitson landed with crewmates Jack Fischer of NASA and Fyoder Yurchikhin of Roscosmos, she broke the record for the most cumulative time in space by a U.S. astronaut. She landed with over 650 days of cumulative flight time and more than 53 hours of spacewalk time. Upon her return, the Human Research Program in Houston studies her health and how the human body adapted to her time in space.

Learn more about the Johnson Space Center online, or on Facebook, Twitter or Instagram.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.


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