The Trickster “Blinking Planetary”

Leap Day…Why Does It Exist?

Once every four years, an extra calendar day is added: a leap day. But why?

The reason for adding leap days to the calendar is to align the calendar year with the actual year – which is defined by the time it takes Earth to circle the sun. It is equal to 365 days, 5 hours, 48 minutes and 46 seconds, or 365.24219 days.

If all calendar years contained exactly 365 days, they would drift from the actual year by about 1 day every 4 years. Eventually, July would occur during the northern hemisphere winter! Wouldn’t that be weird?

To correct (approximately), we add 1 day every 4 years...resulting in a leap year.

By making most years 365 days but every fourth year 366 days, the calendar year and the actual year remain more nearly in step.

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Image Credit:NASA/JPL-Caltech⁣

In this large celestial mosaic, our Spitzer Space Telescope captured a stellar family portrait! You can find infants, parents and grandparents of star-forming regions all in this generational photo.  ⁣ There’s a lot to see in this image, including multiple clusters of stars born from the same dense clumps of gas and dust – some older and more evolved than others. Dive deeper into its intricacies by visiting https://go.nasa.gov/2XpiWLf ⁣

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A Day in Our Lives With X-Ray Tech

On July 23, 1999, NASA’s Chandra X-ray Observatory, the most powerful X-ray telescope ever built, was launched into space. Since then, Chandra has made numerous amazing discoveries, giving us a view of the universe that is largely hidden from view through telescopes that observe in other types of light.

The technology behind X-ray astronomy has evolved at a rapid pace, producing and contributing to many spinoff applications you encounter in day-to-day life. It has helped make advancements in such wide-ranging fields as security monitoring, medicine and bio-medical research, materials processing, semi-conductor and microchip manufacturing and environmental monitoring.

7:00 am: Your hand has been bothering you ever since you caught that ball at the family reunion last weekend. Your doctor decides it would be a good idea for an X-ray to rule out any broken bones. X-rays are sent through your hand and their shadow is captured on a detector behind it. You’re relieved to hear nothing is broken, though your doctor follows up with an MRI to make sure the tendons and ligaments are OK.

Two major developments influenced by X-ray astronomy include the use of sensitive detectors to provide low dose but high-resolution images, and the linkage with digitizing and image processing systems. Because many diagnostic procedures, such as mammographies and osteoporosis scans, require multiple exposures, it is important that each dosage be as low as possible. Accurate diagnoses also depend on the ability to view the patient from many different angles. Image processing systems linked to detectors capable of recording single X-ray photons, like those developed for X-ray astronomy purposes, provide doctors with the required data manipulation and enhancement capabilities. Smaller hand-held imaging systems can be used in clinics and under field conditions to diagnose sports injuries, to conduct outpatient surgery and in the care of premature and newborn babies.

8:00 am: A technician places your hand in a large cylindrical machine that whirs and groans as the MRI is taken. Unlike X-rays that can look at bones and dense structures, MRIs use magnets and short bursts of radio waves to see everything from organs to muscles.

MRI systems are incredibly important for diagnosing a whole host of potential medical problems and conditions. X-ray technology has helped MRIs. For example, one of the instruments developed for use on Chandra was an X-ray spectrometer that would precisely measure the energy signatures over a key range of X-rays. In order to make these observations, this X-ray spectrometer had to be cooled to extremely low temperatures. Researchers at our Goddard Space Flight Center in Greenbelt, Maryland developed an innovative magnet that could achieve these very cold temperatures using a fraction of the helium that other similar magnets needed, thus extending the lifetime of the instrument’s use in space. These advancements have helped make MRIs safer and require less maintenance.

11:00 am:  There’s a pharmacy nearby so you head over to pick up allergy medicine on the way home from your doctor’s appointment.

X-ray diffraction is the technique where X-ray light changes its direction by amounts that depend on the X-ray energy, much like a prism separates light into its component colors. Scientists using Chandra take advantage of diffraction to reveal important information about distant cosmic sources using the observatory’s two gratings instruments, the High Energy Transmission Grating Spectrometer (HETGS) and the Low Energy Transmission Grating Spectrometer (LETGS).

X-ray diffraction is also used in biomedical and pharmaceutical fields to investigate complex molecular structures, including basic research with viruses, proteins, vaccines and drugs, as well as for cancer, AIDS and immunology studies. How does this work? In most applications, the subject molecule is crystallized and then irradiated. The resulting diffraction pattern establishes the composition of the material. X-rays are perfect for this work because of their ability to resolve small objects. Advances in detector sensitivity and focused beam optics have allowed for the development of systems where exposure times have been shortened from hours to seconds. Shorter exposures coupled with lower-intensity radiation have allowed researchers to prepare smaller crystals, avoid damage to samples and speed up their data runs.

12:00 pm: Don’t forget lunch. There’s not much time after your errands so you grab a bag of pretzels. Food safety procedures for packaged goods include the use of X-ray scans to make sure there is quality control while on the production line.

Advanced X-ray detectors with image displays inspect the quality of goods being produced or packaged on a production line. With these systems, the goods do not have to be brought to a special screening area and the production line does not have to be disrupted. The systems range from portable, hand-held models to large automated systems. They are used on such products as aircraft and rocket parts and structures, canned and packaged foods, electronics, semiconductors and microchips, thermal insulations and automobile tires.

2:00 pm: At work, you are busy multi-tasking across a number of projects, running webinar and presentation software, as well as applications for your calendar, spreadsheets, word processing, image editing and email (and perhaps some social media on the side). It’s helpful that your computer can so easily handle running many applications at once.

X-ray beam lithography can produce extremely fine lines and has applications for developing computer chips and other semiconductor related devices. Several companies are researching the use of focused X-ray synchrotron beams as the energy source for this process, since these powerful beams produce good pattern definition with relatively short exposure times. The grazing incidence optics — that is, the need to skip X-rays off a smooth mirror surface like a stone across a pond and then focus them elsewhere — developed for Chandra were the highest precision X-ray optics in the world and directly influenced this work.

7:00 pm: Dream vacation with your family. Finally!  You are on your way to the Bahamas to swim with the dolphins. In the line for airport security, carry-on bags in hand, you are hoping you’ve remembered sunscreen. Shoes off! All items placed in the tray. Thanks to X-ray technology, your bags will be inspected quickly and you WILL catch your plane…

The first X-ray baggage inspection system for airports used detectors nearly identical to those flown in the Apollo program to measure fluorescent X-rays from the Moon. Its design took advantage of the sensitivity of the detectors that enabled the size, power requirements and radiation exposure of the system to be reduced to limits practical for public use, while still providing adequate resolution to effectively screen baggage.  The company that developed the technology later developed a system that can simultaneously image, on two separate screens, materials of high atomic weight (e.g. metal hand guns) and materials of low atomic weight (e.g. plastic explosives) that pass through other systems undetected. Variations of these machines are used to screen visitors to public buildings around the world.

Check out Chandra’s 20th anniversary page to see how they are celebrating.

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Solar System: Things to Know This Week

Our solar system is huge, so let us break it down for you. Here are five things you need to know this week:

1. The Lure of the Rings

Scientists and stargazers alike can’t resist the call of Saturn’s rings, or of its moon Titan. Both have been under close scrutiny by the Cassini spacecraft lately, and there are striking new pictures to prove it. Check out the latest images HERE.

2. A New Moon Rises

The Lunar Reconnaissance Orbiter has captured dramatic landscapes on the moon for more than six years. “A New Moon Rises,” now on display at the Smithsonian National Air and Space Museum in Washington, DC, showcases those images ranging from Apollo landing sites to mountains that rise out of the darkness of the lunar poles. See an online version of the exhibit HERE.  

3. Around the (Giant) World in (Just Under) 88 Days

The Juno mission is closing in on Jupiter. On July 4, the spacecraft enters orbit around the king of planets. Learn more about Juno HERE.

4. Spiders and Volcanoes and Glaciers, Oh My

The more data that New Horizons spacecraft sends down about Pluto and its moons, the more there is to fascinate explorers, from spider-shaped canyons to signs of glacial flow. Take a peek at the new finds on Pluto HERE.

5. World of Wonders

Hexagonal craters, mysterious mountains, eye-catching bright patches — the dwarf planet Ceres is proving to be an intriguing place. The Dawn mission is looking for clues to how it works. See the latest from Ceres HERE.

Want to learn more? Read our full list of the 10 things to know this week about the solar system HERE.

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Space is a Dusty Place!

Butterfly Nebula

When you look at pictures of space, do you know what you’re actually seeing? A lot of the time the answer is dust!

HII region seen by Chandra X-ray Observatory

Clouds of dust drift through our galaxy. Telescopes can take pictures of these clouds when stars light them up. Who knew dust could be so beautiful? But it’s more than just pretty – we can learn a lot from it, too!

Stars like our Sun are born in dust clouds. Over time, leftover dust clumps together to help form planets. That makes it a little less dusty.

At certain times of the year, a band of sun-reflecting dust from the inner Solar System appears prominently just after sunset -- or just before sunrise -- and is called zodiacal light. Credit: Ruslan Merzlyakov/astrorms

But later, objects like comets and asteroids can create new dust by breaking up into tiny rocks. In our solar system, these rocky grains are called zodiacal dust. That’s because it’s mostly visible near the constellations of the zodiac. We can see the hazy glow it creates just after sunset or shortly before dawn sometimes, like in the picture above.

Around other stars, it’s called exozodiacal dust. Try saying that five times fast! It makes it hazy there too, so it can be hard to see distant planets.

Our Nancy Grace Roman Space Telescope will be really good at seeing how much of this dust is swirling around nearby stars. That will help future telescopes know the best places to look to find planets like Earth!

Roman will also see more distant objects. It will peer inside dust clouds where new stars are bursting into life. That will help our James Webb Space Telescope know where to look to find baby planets. Webb can zoom in for a more detailed look at these young worlds by seeing how they filter their host star’s light.

Roman will see huge patches of the sky – much bigger than our Hubble and Webb telescopes can see. These missions will team up to explore all kinds of cosmic mysteries!

Learn more about the exciting science Roman will investigate on Twitter and Facebook.

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5 Space Software Codes We Can Use on Earth

We’ve made some amazingly advanced software for our space missions, from launching rockets to the International Space Station to landing rovers on Mars. But a lot of that software can be applied to other situations here on the ground. We’ve got hundreds of downloadable programs in the NASA Software Catalog available for public use—and they’re all free.

We’ve rounded up five interesting software programs to get your search started.

1. Take a walk on Mars from your living room

Want to walk around Mars from the comfort of your living room? OnSight can help with that. Our engineers and scientists created this mixed reality software to immerse themselves in a visualization of the terrain around the Curiosity rover, so users feel like they are really walking on the Red Planet. The software can be adapted to visualize other locations, which means it could also help us explore places on Earth, like caves and lava fields. No wonder it was awarded NASA’s 2018 Software of the Year! 

2. Enhancing images from space and the doctor’s office

It’s hard to take a perfect picture from space. That’s why our scientists created the Hierarchical Image Segmentation software program – to help us enhance and analyze images taken of Earth from space by the Landsat and Terra missions. But, that isn’t all it can do. Doctors have used the software to analyze medical images, such as X-rays, ultrasounds and mammography images, to reveal important details previously unseen by the human eye.

3. Video game tech helps our engineers build spaceflight hardware

Installing sensitive spaceflight hardware is hardly a time for fun and games. Except when it comes to the Distributed Observer Network, or DON 3.1. This software combines innovative NASA tools with commercial video game technology to train our employees for stressful tasks – like maneuvering important, delicate tools through tight spots when building instruments or spacecraft. DON can be used in many other industries, particularly for overcoming the challenges that face virtual teams collaborating on complex problems.

4. Software helps protect Earth from space junk

Those of us on the ground may imagine space as a peaceful place to float among the stars, but in reality, Earth’s atmosphere is filled with junk. This space debris can cause damage to spacecraft and satellites, including the International Space Station. That’s where the Orbital Debris Engineering Model software program comes in. Thanks to this NASA software, we can study the risks of debris impact to help us protect our orbiting equipment and – more importantly – our planet. Communication companies could use this software to prevent debris damage when launching satellites, saving them a lot of time and money.

5. From exploration missions to your office, this software keeps projects on track

Do you manage complex projects at work? There are a lot of steps and moving pieces in play when it comes to getting a spacecraft from the launchpad into space. Used during the space shuttle missions, the Schedule Test and Assessment Tool 5.0 add-on works with Microsoft Project to automate project data to help us stay on track. It’s one of the more popular programs in our software catalog because it provides quick, clear assessment info that can help with decision making.

These are just a few examples of the software NASA has free and available for the public. To browse the new 2019-2020 catalog online, visit https://software.nasa.gov/.

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What was your reaction to getting selected for the Air Force Fellows program?

Get Ready To Launch America!

A new era of human spaceflight is about to begin. American astronauts will once again launch on an American rocket from American soil to the International Space Station as part of our Commercial Crew Program! NASA astronauts Bob Behnken and Doug Hurley will fly on SpaceX’s Crew Dragon spacecraft, lifting off on a Falcon 9 rocket at 4:32 p.m. EDT May 27, from Kennedy Space Center in Florida, for an extended stay at the space station for the Demo-2 mission. 

As the final flight test for SpaceX, this mission will validate the company’s crew transportation system, including the launch pad, rocket, spacecraft and operational capabilities. This also will be the first time NASA astronauts will test the spacecraft systems in orbit.

Behnken and Hurley were among the first astronauts to begin working and training on SpaceX’s next-generation human space vehicle and were selected for their extensive test pilot and flight experience, including several missions on the space shuttle.

Behnken will be the joint operations commander for the mission, responsible for activities such as rendezvous, docking and undocking, as well as Demo-2 activities while the spacecraft is docked to the space station.

Hurley will be the spacecraft commander for Demo-2, responsible for activities such as launch, landing and recovery.

Lifting off from Launch Pad 39A atop a specially instrumented Falcon 9 rocket, Crew Dragon will accelerate its two passengers to approximately 17,000 mph and put it on an intercept course with the International Space Station. In about 24 hours, Crew Dragon will be in position to rendezvous and dock with the space station. The spacecraft is designed to do this autonomously but astronauts aboard the spacecraft and the station will be diligently monitoring approach and docking and can take control of the spacecraft if necessary.

The Demo-2 mission will be the final major step before our Commercial Crew Program certifies Crew Dragon for operational, long-duration missions to the space station. This certification and regular operation of Crew Dragon will enable NASA to continue the important research and technology investigations taking place onboard the station, which benefits people on Earth and lays the groundwork for future exploration of the Moon and Mars starting with the agency’s Artemis program, which will land the first woman and the next man on the lunar surface in 2024. 

Get excited and follow along on social media using the hashtag #LaunchAmerica! 

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Getting to Mars: A New Rocket for the Journey

Do you know what the structural backbone is of our new rocket, the Space Launch System? If you answered the core stage, give yourself a double thumbs up! Or better yet, have astronaut Scott Kelly do it!

We’re on a journey to Mars. For bolder missions to deep space, we need a big, powerful rocket like SLS to take astronauts in the Orion spacecraft to places we've never gone before. The core stage is a major part of that story, as it will house the fuel and avionics systems that will power and guide the rocket to those new destinations beyond Earth’s orbit. Here's how:

It's Big, and It's Fast.

The core stage will be the largest rocket stage ever built and is under construction right now at our Michoud Assembly Facility in New Orleans. It will stand at 212 feet tall and weigh more than 2.3 million pounds with propellant. That propellant is cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle’s RS-25 engines. In just 8.5 minutes, the core stage will reach Mach 23, which is faster than 17,000 mph!

It's Smart.

Similar to a car, the rocket needs all the equipment necessary for the "drive" to deep space. The core stage will house the vehicle’s avionics, including flight computers, instrumentation, batteries, power handling, sensors and other electronics. That's a lot of brain power behind those orange-clad aluminum walls. *Fun fact: Orange is the color of the rocket's insulation.

It's a Five-Parter.

The core stage is made up of five parts. Starting from the bottom is the engine section, which will deliver the propellants to the four RS-25 engines. It also will house avionics to steer the engines, and be an attachment point for the two, five-segment solid rocket boosters. The engine section for the first SLS flight has completed welding and is in the final phases of manufacturing at Michoud.

Next up is the liquid hydrogen tank. It will hold 537,000 gallons of liquid hydrogen cooled to -423 degrees Fahrenheit. Right now, engineers are building the tank for the first SLS mission. It will look very similar to the qualification test article that just finished welding at Michoud. That's an impressive piece of rocket hardware!

The next part of the core stage is the intertank, which will join the propellant tanks. It has to be super strong because it is the attachment point for the boosters and absorbs most of the force when they fire 3.6 million pounds of thrust each. It's also a "think tank" of sorts, as it holds the SLS avionics and electronics. The intertank is even getting its own test structure at our Marshall Space Flight Center in Huntsville, Alabama.

And then there's the liquid oxygen tank. It will store 196,000 gallons of liquid oxygen cooled to -297 degrees. If you haven't done the math, that's 733,000 gallons of propellant for both tanks, which is enough to fill 63 large tanker trucks. Toot, toot. Beep, beep! A confidence version of the tank has finished welding at Michoud, and it's impressive. Just ask this guy.

The topper of the core stage is the forward skirt. Funny name, but serious hardware. It's home to the flight computers, cameras and avionics. The avionics system is being tested right now in a half-ring structure at the Marshall Center.

You can click here for more SLS core stage facts. We'll continue building, and see you at the launch pad for the first flight of SLS with Orion in 2018!

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Setting the Standards for Unmanned Aircraft

From advanced wing designs, through the hypersonic frontier, and onward into the era of composite structures, electronic flight controls, and energy efficient flight, our engineers and researchers have led the way in virtually every aeronautic development. And since 2011, aeronautical innovators from around the country have been working on our Unmanned Aircraft Systems integration in the National Airspace System, or UAS in the NAS, project.  

This project was a new type of undertaking that worked to identify, develop, and test the technologies and procedures that will make it possible for unmanned aircraft systems to have routine access to airspace occupied by human piloted aircraft. Since the start, the goal of this unified team was to provide vital research findings through simulations and flight tests to support the development and validation of detect and avoid and command and control technologies necessary for integrating UAS into the NAS.  

That interest moved into full-scale testing and evaluation to determine how to best integrate unmanned vehicles into the national airspace and how to come up with standards moving forward. Normally, 44,000 flights safely take off and land here in the U.S., totaling more than 16 million flights per year. With the inclusion of millions of new types of unmanned aircraft, this integration needs to be seamless in order to keep the flying public safe.

Working hand-in-hand, teams collaborated to better understand how these UAS's would travel in the national airspace by using NASA-developed software in combination with flight tests. Much of this work is centered squarely on technology called detect and avoid.  One of the primary safety concerns with these new systems is the inability of remote operators to see and avoid other aircraft.  Because unmanned aircraft literally do not have a pilot on board, we have developed concepts allowing safe operation within the national airspace.  

In order to better understand how all the systems work together, our team flew a series of tests to gather data to inform the development of minimum operational performance standards for detect and avoid alerting guidance. Over the course of this testing, we gathered an enormous amount of data allowing safe integration for unmanned aircraft into the national airspace. As unmanned aircraft are becoming more ubiquitous in our world - safety, reliability, and proven research must coexist.

Every day new use case scenarios and research opportunities arise based around the hard work accomplished by this incredible workforce. Only time will tell how these new technologies and innovations will shape our world.

Want to learn the many ways that NASA is with you when you fly? Visit nasa.gov/aeronautics.



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