Happy Friday! Have a great and safe weekend everyone.
| | JSC TODAY CATEGORIES - Headlines
- Innovation 2014 - Future of Exploration Series
- Save Date: Bring Our Children to Work Registration
- CGE Training for the JSC Traveler
- Win a Spot on the Orion Cake Contest Judging Panel
- Starport's NEW Flex Friday - July 18 - Organizations/Social
- Starport Youth Basketball Camp - Community
- Help JSC Knock Out Hunger! |  |
| Headlines - Innovation 2014 – Future of Exploration Series
As part of Innovation 2014, there has been a series of discussions about NASA's plans for human spaceflight exploration. Please join Monday, July 14th, for the final presentation of the Future of Exploration series, with an in-depth conversation focused on Space Suit and EVA strategy and Human Health/Human Factors considerations for the Asteroid Redirect Crewed Mission. - Save Date: Bring Our Children to Work Registration
The JSC External Relations Office is pleased to present JSC's "Bring Our Children to Work (BOCTW) Day" on Thursday, Aug. 14, at Space Center Houston. Guest speakers, breakout sessions, demonstration booths and hands-on activities will be scheduled throughout the day to further enhance your child(ren)'s experience! Registration opens July 14. A link will be provided in the JSC Today announcement on that day for you to register for the fun filled event. - CGE Training for the JSC Traveler
The JSC CGE Implementation team and the LF\Financial Management Division will be presenting two CGE Traveler Training sessions to introduce the new CGE (Concur Government Edition) travel management system to JSC travelers. The first session will be held on Monday, July 14 from 1:00pm - 2:30pm. The second session will be on Thursday, July 17 from 9:00am - 10:30am. Both sessions will be held in the Building 30 auditorium. Topics that will be covered include How to Access the System, an overview on How to Navigate the System, Updating your User Profile, and How to Activate E-Receipts. - Win a Spot on the Orion Cake Contest Judging Panel
Do you like cake? Consider yourself a confectionery connoisseur? Here is your chance to be on the V.I.P. judging panel for the Orion Cake Decorating contest! What's in it for you? FREE cake and first dibs. Simply email your name to jsc-orion-outreach@mail.nasa.gov by 5pm today! One name will be randomly selected to join our panel of judges at the cake decorating contest. To be a judge, you MUST be available from 11:30am-1pm on Tuesday, July 15th. The selected judge will be notified Monday morning. - Starport's NEW Flex Friday - July 18
We understand that getting over to the Gilruth Center is not easy during those 9 hour days. Because of that, Starport is launching an amazing assortment of FREE programs on FLEX FRIDAY all JSC employees, contractors, and their families! Flex Friday - July 18 Special FREE programs include: - More SPINNING Classes - Nature Walk - Intro to Weight Machines - Intro to Exercise Class - Beginner's Boot Camp Classes - Outer Space OSFX Class
All Starport locations (Gilruth Center, B3, & B11) will also be running a 10% discount on all athletics, recreation, and fitness merchandise!
Organizations/Social - Starport Youth Basketball Camp
Starport's Youth Basketball camp starts next week! Sign up today or over the weekend to reserve your spot for Monday! $150 per child $15 off registration fee for sibling sign-ups Community - Help JSC Knock Out Hunger!
School may be out, but Hunger is not! Our goal this year is to collect 60,000 pounds of food to locally benefit the Clear Lake Food Pantry & the Galveston County Food Bank. More than 200 families in our area are served by the Clear Lake Food Pantry, and the Galveston County Food Bank serves approximately 52,000 Galveston County residents. 47% of those in need are children. Nearly 24,000 children in Galveston County are on free or reduced-priced school lunches. During the summer months these kids may go without a source for nutritious meals. Through various programs & participating agencies the Galveston County Food Bank can ensure these little tummies are being filled, but we need your help! For the next week JSC is collecting "portable meals" - hamburger/tuna helper, canned soups, stews, all in one meals. Donation bins are located in various buildings across site and both cafes. | |
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| JSC Today is compiled periodically as a service to JSC employees on an as-submitted basis. Any JSC organization or employee may submit articles. Disclaimer: Accuracy and content of these notes are the responsibility of the submitters. |
NASA and Human Spaceflight News
Friday – July 11, 2014
INTERNATIONAL SPACE STATION: ISS astronaut Reid Wiseman has been posting pictures of Typhoon Neoguri to his Twitter account, @astro_reid. His images have been used on more than 200 TV broadcasts and featured in CNN, The Washington Post, Slate Magazine, NBC News, Gizmodo and more. The photo below has nearly 8,000 retweets. HEADLINES AND LEADS
GenCorp Says AJ-26 Test Failure Cost Company $13.5 Million
Peter B. de Selding – Space News
GenCorp Inc., parent company of rocket-engine builder Aerojet Rocketdyne, on July 9 said the failure of an AJ-26 engine during a test firing in May cost the company $13.5 million in lost sales and higher costs for the six months ending May 31.
Soyuz Rocket Launches Second Batch of O3b Satellites from French Guiana
Peter B. de Selding – Space News
A Europeanized Russian Soyuz rocket on July 10 successfully placed four O3b Networks Ka-band broadband satellites into their unusual medium Earth orbit in the second of three planned four-satellite launches for the company. The third launch is scheduled for early next year.
Fireball as Russian space junk 'belly flops' to Earth above Australia
Hilary Whiteman - CNN
A fireball the size of a small truck, which shot through the sky over Australia Thursday night, was space junk from Russia's Soyuz rocket, astronomers said.
Mercury probe monitors Sun and space weather too
Paul Sutherland – SEN
NASA's MESSENGER probe has been orbiting the innermost planet Mercury since March 2011, sending back more than 200,000 images of that rocky world.
SpaceX Just Got Permission to Build a Spaceport in Texas
Jason Koebler – MOTHERBOARD
SpaceX just got approval from the Federal Aviation Administration to build a 56.5-acre spaceport along the Gulf of Mexico on the Texas-Mexico border—a huge step toward actually making the spaceport a reality.
Hubble Space Telescope shows astronomers a string of cosmic pearls they've never seen
Lee Roop – Huntsville (AL) Times
Astronomers are using words like "awesome" and "exciting" to describe the implications of a recent Hubble Space Telescope photograph. The photograph – wrap your head around this – shows a structure 100,000 light years long made of two colliding galaxies linked by a corkscrewing string of newly born stars.
Supermoon is here again
Doyle Rice – USA Today
The full moon this weekend will be another so-called "Supermoon," the first of three to grace the sky this year. Since the moon is "fullest" early Saturday morning, you can look for the Supermoon both Friday and Saturday nights.
NASA MESSENGER Spacecraft Reveals High-Energy Processes of the Sun from Mercury
Catherine Griffin - Science World Report
Astronomers are learning a bit more about the high-energy processes that occur on the sun. NASA's MESSENGER spacecraft and STEREO measurements have opened up a new way for scientists to understand exactly what's happening within our nearest star.
NASA Plans Tests Of Distributed Electric Propulsion
Light aircraft are early targets for the efficiency and safety benefits touted for electric propulsion
Graham Warwick | Aviation Week & Space Technology
Aviation did not enter the Jet Age overnight, and a decades-long journey to the next propulsion paradigm may already be underway. At NASA, the exploration has begun with plans for ground and flight tests to determine whether hybrid and distributed electric propulsion could be the next disruptive shift in civil aviation.
COMPLETE STORIES
GenCorp Says AJ-26 Test Failure Cost Company $13.5 Million
Peter B. de Selding – Space News
GenCorp Inc., parent company of rocket-engine builder Aerojet Rocketdyne, on July 9 said the failure of an AJ-26 engine during a test firing in May cost the company $13.5 million in lost sales and higher costs for the six months ending May 31.
The incident forced Dulles, Virginia-based Orbital Sciences Corp. to delay the launch of its Antares rocket, which uses two AJ-26 engines as its first stage, to determine whether the test-stand failure indicated a wider issue with the AJ-26. The company has since cleared the AJ-26 engine now on the Antares rocket and is proceeding with the launch, carrying an unmanned cargo freighter to the international space station.
Rancho Cordova, California-based GenCorp, in a filing with the U.S. Securities and Exchange Commission, said that as of May 31 it had eight more AJ-26 engines to deliver to Orbital under its current contract.
Orbital officials have said the company is likely to use ATK-supplied motors for Antares for the long term. Orbital is merging with ATK's aerospace and defense business in a deal expected to close by the end of the year.
It is unclear whether a new Orbital-GenCorp contract for an interim supply of AJ-26 engines will be signed.
In the filing, GenCorp also said it had exercised an option to extend, by three months, the deadline by which either GenCorp or United Technologies Corp. could cancel their agreement relating to Russia's RD-180 engine, which powers the U.S. Atlas 5 rocket used mainly for U.S. government missions.
Hartford, Connecticut-based United Technologies sold its Pratt & Whitney Rocketdyne engine division to GenCorp in a transaction announced in July 2012 and concluded in June 2013. The agreement had included the transfer to GenCorp of United Technologies' 50 percent ownership of RD Amross, a joint venture with RD-180 manufacturer NPO Energomash of Khimki, Russia, that imports and sells the engines to Atlas 5 maker United Launch Alliance.
The transfer of the RD Amross shares has been awaiting approval by the Russian government since then, and GenCorp had reduced its purchase price of the Rocketdyne division by $55 million as a consequence. United Technologies and GenCorp agreed that either company could cancel the RD Amross transaction starting 12 months after the transaction's closure, meaning June 12 of this year.
Either party is also permitted to extend the deadline by as much as a year, in three-month increments. GenCorp said that on May 30 it exercised the first three-month extension, to September 12.
GenCorp did not say whether the current debate about whether Atlas 5 should continue to use a Russian engine given the political tensions with Russia had changed the company's thinking about the RD Amross purchase.
Soyuz Rocket Launches Second Batch of O3b Satellites from French Guiana
Peter B. de Selding – Space News
A Europeanized Russian Soyuz rocket on July 10 successfully placed four O3b Networks Ka-band broadband satellites into their unusual medium Earth orbit in the second of three planned four-satellite launches for the company. The third launch is scheduled for early next year.
Operating from Europe's Guiana Space Center on the northeast coast of South America, the Soyuz-Fregat vehicle separated the satellites two at a time into an orbit with an altitude of some 7,836 kilometers.
O3b Chief Executive Steve Collar said shortly thereafter that ground teams had picked up signals from all four satellites.
The satellites will use their own propulsion systems to reach their final operating positions at 8,062 kilometers in altitude, inclined at 0.4 degrees relative to the equator. Orbit-raising and satellite system testing are expected to take about three weeks.
The O3b orbit is close enough to Earth's surface to reduce the latency involved in sending signals to and from satellites in geostationary orbit at 36,000 kilometers above the equator.
Satellite fleet operator SES of Luxembourg is a major O3b shareholder and has said that once the O3b business model is proven, it intends to move toward majority ownership of the company, which will provide Internet backbone and other services on a wholesale basis in the world's equatorial regions. SES officials have said the frequency and orbital rights that O3b has — no one else uses this orbit — are such that more than 100 O3b satellites could be launched to provide ever-more throughput and require less work on the part of the steerable ground antennas that follow one satellite before picking up another to assure data continuity.
The O3b satellites each weigh about 700 kilograms at launch and were built by Thales Alenia Space of France and Italy, which has made a specialty of manufacturing low orbiting constellations with the help of France's export-credit agency, Coface, which has provided low-interest loans to satellite fleet operators.
Thales Alenia Space also built major portions of the first- and second-generation spacecraft for the Globalstar mobile communications network, and is under contract to build 81 second-generation satellites for mobile satellite services provider Iridium.
O3b, based in Britain's Channel Islands, has already started limited commercial operations with its first four satellites, which launched in June 2013, despite a power defect that does not affect their performance but is expected to shorten their contractual 10-year operating life.
The issue prompted the company to file a claim with its insurance underwriters for about $240 million; a separate claim for another $81 million was filed more recently. Both claims are still being reviewed by the underwriters.
Industry officials said it is uncertain when the satellites' power will fall to levels that materially degrade service quality. That is not yet the case, but the situation has increased the pressure to get more satellites on orbit and thus created tensions with the executive commission of the European Union, which wanted its own Galileo positioning, navigation and timing satellites to be launched aboard the Soyuz ahead of O3b.
Evry, France-based Arianespace was placed in the difficult position of arbitrating between O3b, whose network could include dozens of Arianespace-launched satellites — in addition to O3b's links to SES and its 55-satellite telecommunications fleet — and the European Commission, whose Galileo and Copernicus Earth observation constellations make it Arianespace's largest single customer.
The on-board power problem forced O3b to forego a 2013 launch on the Soyuz, and upended Arianespace's planned 2013 flight manifest and revenue forecast. The European Union's Galileo network faced similar satellite-delivery delays, pushing its launches to 2014. The first of those Galileo launches is now scheduled for late August, with second slated for late this year.
But O3b and SES officials in recent weeks have maintained pressure on Arianespace for a late-2014 launch, which likely would mean pushing Galileo into 2015.
Fireball as Russian space junk 'belly flops' to Earth above Australia
Hilary Whiteman - CNN
A fireball the size of a small truck, which shot through the sky over Australia Thursday night, was space junk from Russia's Soyuz rocket, astronomers said.
More accurately, it was "object 40077," the third stage of the Soyuz rocket which was launched from Kazakhstan on Tuesday.
It was hurtling around the Earth at some 18,000 mph, or almost 29,000 kilometers per hour.
"What you're seeing in that fireball is it slowing down really fast. It's belly-flopping on the world's atmosphere at 18,000 miles an hour. That really hurts," said Jonathan McDowell, astronomer at the Harvard-Smithsonian Center for Astrophysics.
Residents who saw the fireball initially guessed it was a meteor. Some feared it was a plane crash and called emergency services. Photos started popping on Twitter with the hashtag #meteor.
"Just saw the biggest meteor I've ever seen, going all way across the sky heading North, amazing!" Justin Nicholas tweeted.
Steve Wright was on the rooftop of a car park trying to take a photo of the Melbourne Star -- the city's giant Ferris wheel -- when he saw the fireball streaking through the sky.
"I had no idea what it was, and at first I thought it was a low flying jet with some wild vapor trails, because it was moving that fast," he told CNN. "But because there was no sound, and it didn't make sense to see a vapor tail it behind the plane at night, I knew it had to be something else."
While the fireball came as a surprise to residents, McDowell said astronomers had an early warning.
Russia launched its Soyuz rocket on July 8 from the Baikonur Cosmodrome in Kazakhstan, carrying the Meteor-M2 weather satellite and other smaller satellites.
The projected path of the third stage of the rocket showed it moving northbound between Melbourne and Canberra.
"They're not usually seen because most of the Earth is either ocean -- or very sparsely inhabited. And of course, if it comes down in the daytime, you may not notice as easily," McDowell said.
"You get reports like this a few times a year. Maybe once or twice a year, but it happens much more often."
One user on Twitter couldn't let the relatively rare opportunity pass without using it as an excuse to join the latest meme involving Australian Prime Minister Tony Abbott.
The Australian leader released an image earlier this week striking a pose with Japanese Prime Minister Shinzo Abe.
Around 1,000 of these types of space junk have re-entered orbit since the start of the space age, McDowell said.
"It's possible that some of the pieces might reach the ground but most of it would melt away."
Mercury probe monitors Sun and space weather too
Paul Sutherland – SEN
NASA's MESSENGER probe has been orbiting the innermost planet Mercury since March 2011, sending back more than 200,000 images of that rocky world.
But its unique position has also allowed it to make close-up studies of activity on the Sun and the effects in that region of the Solar System of space weather.
MESSENGER, which was launched in 2004, gets as close as 45 million km (28 million miles) to our home star, which allows it to detect short-lived neutrons created in solar flares.
These solar neutrons last, on average, only about 15 minutes which means they do not travel far enough to be observed by particle detectors on any satellites orbiting Earth. But scientists believe they have been detected by MESSENGER.
The neutrons are thought to have been created when a solar flare erupted on 4 June, 2011, on the far side of the Sun from the Earth, meaning it was missed by ground-based telescopes. However, NASA's Solar Terrestrial Relations Observatory (STEREO) was in a position where it got a clear view of the flare.
David Lawrence, of The Johns Hopkins Applied Physics Lab in Laurel, Maryland, looked at data recorded by MESSENGER from 4 and 5 June, 2011. The data showed an increase in the number of non-charged neutrons at Mercury's orbit hours before charged particles from the flare reached the spacecraft.
This told the team that the neutrons were probably produced by accelerated flare particles striking the lower solar atmosphere, releasing neutrons as a result of high-energy collisions.
Lawrence, who is first author of a paper published this week in Geophysical Research: Space Physics, said: "To understand all the processes on the Sun we look at as many different particles coming from the Sun as we can—photons, electrons, protons, neutrons, gamma rays—to gather different kinds of information.
"Closer to Earth we can observe charged particles from the sun, but analysing them can be a challenge as their journey is affected by magnetic fields."
Charged particles from the Sun twirl and gyrate around the magnetic field lines created by the vast magnetic systems that surround it and the Earth. Neutrons, however, as they are not electrically charged, travel in straight lines from the flaring region.
They can carry information about flare processes unperturbed by the environment through which they move. This information can be used by scientists to decipher one aspect of the complicated acceleration processes that are responsible for creating highly energetic and fast solar particles.
MESSENGER's studies of the solar wind of particles streaming off the Sun have also helped scientists spot for the first time, a classic space weather event called a hot flow anomaly, or HFA, from the distance of Mercury. It has previously been spotted at Earth, Venus, Saturn and Mars.
Vadim Uritsky, of NASA's Goddard Space Flight Center in Greenbelt, Maryland, said: "Planets have a bow shock the same way a supersonic jet does. These hot flow anomalies are made of very hot solar wind deflected off the bow shock."
This first sighting of HFAs at Mercury helps scientists to build a picture of space weather across the Solar System.
SpaceX Just Got Permission to Build a Spaceport in Texas
Jason Koebler – MOTHERBOARD
SpaceX just got approval from the Federal Aviation Administration to build a 56.5-acre spaceport along the Gulf of Mexico on the Texas-Mexico border—a huge step toward actually making the spaceport a reality.
Wednesday, the FAA, which handles all commercial space launch permitting in the United States, issued what's known as a "Record of Decision" that suggests the agency would grant launch licenses to the company to operate out of a location about 17 miles east of Brownsville. The FAA says it would likely approve any requests from SpaceX to launch as many as 10 Falcon 9 rockets and two Falcon Heavy rockets per year out of the spaceport, through at least 2025.
"This record of decision provides the FAA's final… approval to support the issuance of launch licenses and/or experimental permits that would allow SpaceX to launch the Falcon 9 and Falcon Heavy orbital vertical launch vehicles and a variety of reusable suborbital launch vehicles from a launch site on privately owned property in Cameron County, Texas," the decision stated.
That's the second bit of good news SpaceX has gotten from the FAA in the last couple months—at the end of May, the agency's environmental impact assessment suggested that the spaceport poses no serious environmental danger. The company has promised to set up a sea turtle monitoring plan, and the FAA also notes that there are ocelots and jaguarundi, two extremely rare wild cats, living in the area. To mitigate the danger to those cats, there will be ocelot crossing warning signs put up, and speed limit for vehicles on the launch site will be limited to 25 miles per hour.
This isn't the end of SpaceX's regulatory race to begin launching from a private facility, however. The company will still need approval from several state agencies, including the Texas Department of Transportation, in order to do things like build new roads and move utility lines.
The FAA's approval, however, should be the last federal hangup before the company can build the spaceport.
Right now, the company is launching its rockets out of Cape Canaveral in Florida, and Vandenberg Air Force Base in California. The company has also looked into spaces in Georgia and Florida, but the Texas site is looking like the most promising option—which means it's the best bet for the company's first major spaceport.
Hubble Space Telescope shows astronomers a string of cosmic pearls they've never seen
Lee Roop – Huntsville (AL) Times
Astronomers are using words like "awesome" and "exciting" to describe the implications of a recent Hubble Space Telescope photograph. The photograph – wrap your head around this – shows a structure 100,000 light years long made of two colliding galaxies linked by a corkscrewing string of newly born stars.
You can't find a mundane explanation for this," German astronomer Grant Tremblay said in a NASA statement.
Scientists have seen the "beads on a string" phenomenon before on the arms of spiral galaxies and between galaxies. They've never seen one corkscrewing through two giant, merging galaxies.
Scientists have three possible explanations for the phenomenon and will try to figure which one is correct. Whatever the origin of the chain, Tremblay said "the result is awesome."
Supermoon is here again
Doyle Rice – USA Today
The full moon this weekend will be another so-called "Supermoon," the first of three to grace the sky this year. Since the moon is "fullest" early Saturday morning, you can look for the Supermoon both Friday and Saturday nights.
A Supermoon occurs when the moon is somewhat closer to Earth than it typically is, and the effect is most noticeable when it occurs at the same time as a full moon, according to James Garvin, chief scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.
The other Supermoons will be in August and September. The one on Aug. 10 will be the biggest of the year, as the moon will be closest to Earth on that day.
The best time to look at the full moon is when it's near the horizon. That is when illusion mixes with reality to produce a truly stunning view, NASA reports. Low-hanging moons look unnaturally large when they beam through trees, buildings and other foreground objects.
Supermoon is a relatively recent term, likely first coined by an astrologer about 30 years ago, reports EarthSky's Bruce McClure. Before that, "we called them a perigee full moon...Perigee just means 'near Earth,'" he writes.
If you're tired of the Supermoon hysteria, other names for the July, August and September full moons are the Buck, Sturgeon and Corn Moon, respectively, reports David Dickinson of Universe Today
NASA MESSENGER Spacecraft Reveals High-Energy Processes of the Sun from Mercury
Catherine Griffin - Science World Report
Astronomers are learning a bit more about the high-energy processes that occur on the sun. NASA's MESSENGER spacecraft and STEREO measurements have opened up a new way for scientists to understand exactly what's happening within our nearest star.
The MESSENGER spacecraft orbits Mercury, and is as close as 28 million miles to the sun as opposed to Earth's 93 million miles. In fact, the spacecraft is near enough to detect solar neutrons that are created in solar flares, which are powerful bursts of radiation. Solar neutrons only last about 15 minutes, and how far they travel from the sun and into space largely depends on their speed. This means that slower neutrons don't travel fast or far enough to be seen by particle detectors in orbit around Earth.
"To understand the processes on the sun we look at as many different particles coming from the sun as we can-photons, electrons, protons, neutrons, gamma rays-to gather different kinds of information," said David Lawrence, first author of a paper examining these particles, in a news release. "Closer to Earth we can observe charged particles from the sun, but analyzing them can be a challenge as their journey is affected by magnetic fields." In order to learn a bit more about these particles, the researchers looked at MESSENGER data that corresponded to solar flares that were accompanied by fast-moving energetic charged particles. Then, the scientists used NASA's Solar Terrestrial Relations Observatory (STEREO) spacecraft to examine the flare itself.
In the end, the researchers found that there was an increase in the number of neutrons at Mercury's orbit hours before the large number of particles reached MESSENGER. This showed that the neutrons were most likely produced by accelerated flare particles striking the lower solar atmosphere, releasing neutrons as a result of high-energy collisions.
The findings don't just reveal a bit more about solar processes, though; they also show that MESSENGER in combination with STEREO can provide a clearer and better view of our nearest star.
The latest findings are published in the Journal of Geophysical Research: Space Physics.
NASA Plans Tests Of Distributed Electric Propulsion
Light aircraft are early targets for the efficiency and safety benefits touted for electric propulsion
Graham Warwick | Aviation Week & Space Technology
Aviation did not enter the Jet Age overnight, and a decades-long journey to the next propulsion paradigm may already be underway. At NASA, the exploration has begun with plans for ground and flight tests to determine whether hybrid and distributed electric propulsion could be the next disruptive shift in civil aviation.
A wing carried high above a truck racing across the dry lakebed at Edwards AFB, California, in November could provide the first validated data to prove that distributed electric propulsion can offer the promised benefits. The 31-ft.-span wing will carry 18 small electrically driven propellers, and is a precursor to a small X-plane demonstrator proposed under NASA's new Transformative Aeronautics Concepts program.
In parallel, over the next five years, the agency wants to develop technology for compact, high-power-density electric motors generating 1-2 megawatts—sufficient to power an all-electric general-aviation aircraft or helicopter, a hybrid turbine-electric regional airliner or a large transport with many small engines distributed around the aircraft in ways that make it safer and more energy-efficient.
The sweet spot for a first generation of electric-powered aircraft seems to be between 1 and 2 megawatts, says Ruben Del Rosario, NASA Fixed Wing program manager. But the agency also sees an intersection of unmanned and personal air vehicles around electrical propulsion and increasing autonomy, beginning this spiral exploration with small unmanned aerial systems (UAS) (see page 20) and light aircraft.
"What problems are we trying to solve in general aviation?" Mark Moore, advanced concepts engineer at NASA Langley Research Center, reflects. His answer is many, and they encompass the low efficiency; poor safety, emissions and ride quality; and high operating costs of some light aircraft and helicopters.
Distributed electric propulsion promises dramatic increases in aerodynamic and propulsive efficiency, and reductions in noise and energy costs. "It is not just about general aviation, but they are earlier adopters at a smaller scale, faster and cheaper," Moore says.
Electric propulsion is not without its penalties. Energy-storage weights are far worse than those of aviation fuel, and battery-pack costs are high. But electric motors are more efficient than turbines or pistons across a wide rpm range, and power-to-weight ratios are higher; they are quiet, compact and reliable, with zero emissions and energy costs that are much lower than for aviation fuel. And, crucially for aircraft design, efficiency and power-to-weight are independent of size.
"You can have multiple small electric motors with the same output as a large one without much penalty. You can put them anywhere around the aircraft, versus heavy piston engines that can only go in one or two places," says Joby Aviation's Alex Stoll, chief designer of the Lotus small UAS and two-seat S2, both vertical-takeoff-and-landing designs using distributed electric propulsion. "You can use them to make a personal air vehicle practical, versus an expensive, noisy, unsafe helicopter."
To test the premise that the tighter propulsion-airframe integration possible with electric power will deliver efficiency, safety and environmental and economic benefits, NASA has partnered with Empirical Systems Aerospace (ESAero) and Joby to propose the Leading Edge Asynchronous Propeller Technology (LEAPTech) demonstrator as an X-plane testbed for distributed electric propulsion.
A traditional light aircraft needs a large wing to meet the low stall-speed requirement for certification, but this is inefficient in cruise. LEAPTech replaces the big wing with one that is one-third the size for lower drag, and has three times the wing loading for better ride quality. Cruise lift-to-drag ratio at 200 mph is greater than 20, versus 11 for a comparable Cirrus SR22, NASA estimates.
To achieve the required 61-kt. stall speed with such a small wing, LEAPTech mounts an array of small propellers along the leading edge. These accelerate airflow over the wing, increasing dynamic pressure at the leading edge and more than doubling the maximum lift coefficient (CLmax) at low speed. "In computational fluid dynamics, we have seen lift coefficients of 5.5. We need 4.5 for a 61-knot stall," says Stoll. Unblown, with full-span Fowler flaps deployed 40 deg., CLmax is 2.7, says Moore.
Optimized for low speed, the small-diameter, high-solidity propellers have low tip speeds, around 450 ft./sec. compared with an SR22's 919 ft./sec., for reduced noise. In addition, they all operate at slightly different speeds to spread the frequencies and reduce the annoyance. The props blow the wing for takeoff and landing, but fold back to reduce drag in cruise, at which point wingtip propellers optimized for high speed provide propulsion, operating inside the wingtip vortices to increase efficiency.
The intent of LEAPTech is to modify a Tecnam P2006T light twin with the new wing, to provide a direct comparison between conventional and distributed-electric propulsion. But the first step is the Hybrid-Electric Integrated Systems Testbed (Heist), a truck-mounted rig that will enable NASA to ground-test a full-scale wing at the 61-kt. stall condition at lower cost than a wind-tunnel test.
"NFAC [National Full-Scale Aerodynamics Complex wind-tunnel facility] would have cost more than the entire budget [for Heist]," says Moore. "And we need to get to this scale to have reasonable data." The wing will float on an airbag system in the truck to minimize vibration from the lakebed, and the remaining noise will be removed during post-processing to obtain lift measurements with less than 5% error, he says.
ESAero is the prime contractor for Heist. Joby Aviation is building the test rig, wing, motors and props. Combined, the 18 propellers will generate 300 hp and the wing will provide 3,500 lb. of lift. ESAero will conduct shakedown tests on a paved runway before the lakebed tests in November. "We will get ground vibration . . . [but] are confident we can get clean data on lift, drag and pitching moment," says NASA Armstrong Flight Research Center project engineer Sean Clark.
In parallel, NASA is beginning fundamental research to understand and overcome the challenges of electric propulsion. Now taking shape at Armstrong, the Airvolt test stand will be used to characterize each element of a single-string propulsion system, from batteries to propeller. A year from now, this will be upgraded to the Airvolt Hybrid, with a Rolls-Royce M250 turboshaft, electric motor/generator and enlarged batteries. This will be arranged so that both the gas turbine and electric motor can drive the propeller, and will be used to look at power-transfer stability issues with parallel hybrid propulsion.
In February 2016, NASA Armstrong plans to begin the Heist power management and distribution (PMAD) ground demonstration. This will be a static propulsion test stand co-located with Airvolt and used as a long-term research platform. NASA plans to evaluate stability issues inherent in parallel-hybrid electric bus architectures, characterize aggregate thrust control of many motors, investigate algorithms for thrust-augmented yaw control and to assess power generation and consumption problems such as catastrophic load shedding, says Clark.
"We will take the wing off the truck, put it on a static test stand and start to do power distribution studies," he says. These will include shifting between batteries and turbine-driven generator feeding the distributed power bus, and stabilizing the high-frequency electrical loads from the motors. "We will study how to schedule power for yaw control, and how to integrate prognostic health monitoring," including sensors on the motors, Clark says.
A distributed propulsion electronic controller will translate thrust targets input by the pilot into individual thrust commands for each of the propulsors, while managing the balance between power generation, storage and consumption. A control algorithm will manage the loading of the generator, real-time capacity of the energy storage buffer and power demand from the collection of propulsors. Another algorithm will synthesize individual propulsor commands based on total thrust targets and generator- and stored-power availability.
Heist will use 100-120-volt electrical systems. "That's not optimal, but it allows us to do [Heist] within a year, and we do not care about weight," says Andrew Gibson, ESAero business-development president. NASA plans to move to a 600-volt system to reduce distribution wiring weight. "It's the sweet spot; [there are] no arcing concerns and components are available today," says Clark.
To follow PMAD, NASA plans hardware-in-the-loop tests to integrate flight-like electric propulsion hardware with simulated aircraft flight controls. Next up will be aircraft-in-the-loop "iron bird" tests with real controls surfaces, flight-ready control system and flight-like energy storage components. The iron bird would test systems for a kilowatt-class distributed electric propulsion X-plane, the LEAPTech, and a 1-2 megawatt hybrid-electric flight demonstrator, notionally one of NASA's Northrop Grumman RQ-4 Global Hawk unmanned aircraft.
Clark says the iron bird will be used to assess actual electric-propulsion implementation effects such as real-world volume and weight constraints, to address failure modes and recovery strategies, identify and resolve interdependencies between propulsion and other systems, validate aero-propulsive efficiency gains and demonstrate realistic performance benefits from propulsion-airframe integration.
While it seems futuristic, distributed electric propulsion is on the near horizon for light aircraft. Companies such as Joby and secretive Zee.aero are designing personal aircraft around the concept, knowing they must wait for batteries and motors to improve. Joby plans to fly the S2 in 1-2 years and certificate it in "a few years," says Stoll, who believes "by 2020 electric aircraft will fly 500 miles at 200 mph."
Moore believes electric propulsion, coupled with autonomy, will spark a breakthrough in on-demand aviation and that the technology will move up to larger aircraft over time, because, just as "the PC came before the Internet, transformative vehicles lead transformative capabilities," he says. "As you go up in size, the benefits decrease because larger aircraft are already more efficient. But it is still compelling."
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