Apr 21 2016
From The Space Library
Microscopic "Timers" Reveal Likely Source of Galactic Space Radiation
Most of the cosmic rays that we detect at Earth originated relatively recently in nearby clusters of massive stars, according to new results from NASA's Advanced Composition Explorer (ACE) spacecraft. ACE allowed the research team to determine the source of these cosmic rays by making the first observations of a very rare type of cosmic ray that acts like a tiny timer, limiting the distance the source can be from Earth.
"Before the ACE observations, we didn't know if this radiation was created a long time ago and far, far away, or relatively recently and nearby," said Eric Christian of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Christian is co-author of a paper on this research published April 21 in Science.
Cosmic rays are high-speed atomic nuclei with a wide range of energy -- the most powerful race at almost the speed of light. Earth's atmosphere and magnetic field shield us from less-energetic cosmic rays, which are the most common. However, cosmic rays will present a hazard to unprotected astronauts traveling beyond Earth's magnetic field because they can act like microscopic bullets, damaging structures and breaking apart molecules in living cells. NASA is currently researching ways to reduce or mitigate the effects of cosmic radiation to protect astronauts traveling to Mars.
Cosmic rays are produced by a variety of violent events in space. Most cosmic rays originating within our solar system have relatively low energy and come from explosive events on the sun, like flares and coronal mass ejections. The highest-energy cosmic rays are extremely rare and are thought to be powered by massive black holes gorging on matter at the center of other galaxies. The cosmic rays that are the subject of this study come from outside our solar system but within our Galaxy and are called galactic cosmic rays. They are thought to be generated by shock waves from exploding stars called supernovae.
The galactic cosmic rays detected by ACE that allowed the team to estimate the age of the cosmic rays, and the distance to their source, contain a radioactive form of iron called Iron-60 (60Fe). It is created inside massive stars when they explode and then blasted into space by the shock waves from the supernova. Some 60Fe in the debris from the destroyed star is accelerated to cosmic-ray speed when another nearby massive star in the cluster explodes and its shock wave collides with the remnants of the earlier stellar explosion.
60Fe galactic cosmic rays zip through space at half the speed of light or more, about 90,000 miles per second. This seems very fast, but the 60Fe cosmic rays won't travel far on a galactic scale for two reasons. First, they can't travel in straight lines because they are electrically charged and respond to magnetic forces. Therefore they are forced to take convoluted paths along the tangled magnetic fields in our Galaxy. Second, 60Fe is radioactive and over a period of about 2.6 million years, half of it will self-destruct, decaying into other elements (Cobalt-60 and then Nickel-60). If the 60Fe cosmic rays were created hundreds of millions of years or more ago, or very far away, eventually there would be too little left for the ACE spacecraft to detect.
"Our detection of radioactive cosmic-ray iron nuclei is a smoking gun indicating that there has likely been more than one supernova in the last few million years in our neighborhood of the Galaxy," said Robert Binns of Washington University, St. Louis, Missouri, lead author of the paper.
"In 17 years of observing, ACE detected about 300,000 galactic cosmic rays of ordinary iron, but just 15 of the radioactive Iron-60," said Christian. "The fact that we see any Iron-60 at all means these cosmic ray nuclei must have been created fairly recently (within the last few million years) and that the source must be relatively nearby, within about 3,000 light years, or approximately the width of the local spiral arm in our Galaxy." A light year is the distance light travels in a year, almost six trillion miles. A few thousand light years is relatively nearby because the vast swarm of hundreds of billions of stars that make up our Galaxy is about 100,000 light years wide.
There are more than 20 clusters of massive stars within a few thousand light years, including Upper Scorpius (83 stars), Upper Centaurus Lupus (134 stars), and Lower Centaurus Crux (97 stars). These are very likely major contributors to the 60Fe that ACE detected, owing to their size and proximity, according to the research team.
ACE was launched on August 25, 1997 to a point 900,000 miles away between Earth and the sun where it has acted as a sentinel, detecting space radiation from solar storms, the Galaxy, and beyond. This research was funded by NASA's ACE program.
Additional co-authors on this paper were: Martin Israel and Kelly Lave at Washington University, St. Louis, Missouri; Alan Cummings, Rick Leske, Richard Mewaldt and Ed Stone at Caltech in Pasadena, California; Georgia de Nolfo and Tycho von Rosenvinge at Goddard; and Mark Wiedenbeck at NASA's Jet Propulsion Laboratory in Pasadena, California.
Gene Analysis System Could Accelerate Pace of Research on the Space Station
Biologists around the world routinely perform gene expression analysis to better understand living systems. Gene expression analysis examines the types and amounts of molecules produced by genes in living cells, telling us which genes are active and which are inactive at a given point in time. This reveals valuable information about the highly dynamic internal states of cells in living systems. NASA’s WetLab-2 hardware system is bringing to the International Space Station the technology to measure gene expression of biological specimens in space, and to transmit the results to researchers on Earth at the speed of light.
“WetLab-2 is truly a first,” said Macarena Parra, WetLab-2 project scientist at NASA’s Ames Research Center in California’s Silicon Valley. “Investigators using WetLab-2 will be able to analyze the first run of a spaceflight experiment and immediately apply what they learn to subsequent runs of the experiment during the same flight mission. It will allow us to accelerate the pace of research on the station while saving time and cost.”
Currently, life science research aboard the space station must follow pre-set plans: A rocket carries the experiment into space, an astronaut follows the plan and then sends samples to Earth for analysis. If the post-flight analysis shows that something unusual or unpredicted occurred in space, the researcher will want to further study those phenomena, but this requires planning an entirely new experiment and waiting for an opportunity to fly it to the station.
WetLab-2 employs a standard method of measuring gene expression called Quantitative Polymerase Chain Reaction, or qPCR, which involves extracting certain types of ribonucleic acid (RNA) molecules from biological samples and then measuring the amounts extracted. RNA molecules are found inside cells, and they play key roles in the basic functions of living cells, such as making cellular proteins. Today, qPCR analysis is performed in many biology labs around in the world. The WetLab-2 system uses a commercially available instrument to perform the qPCR analysis on the space station.
Microgravity complicates even the simplest laboratory procedures, such as adding liquid to a test tube. Additionally, on the station, a complete pantry of chemicals is not available, and astronauts maintain a packed schedule. To address these constraints, the WetLab-2 team developed a new method to allow station crew members to extract RNA from multiple types of biological specimens in less than 30 minutes.
“This innovative RNA extraction technology, currently in the patenting process, was a multidisciplinary effort of cell biologists, chemical engineers and mechanical engineers who designed the sample manipulation and processing chemistry,” said Julie Schonfeld, WetLab-2 project manager at Ames.
WetLab-2 will enable a broad range of life science investigations in space, such as analysis of genes that indicate infectious disease, cell stress, changes in cell cycle growth and development, and genetic abnormality. Researchers also can use the system for real-time analyses of air, surface and water samples to monitor environmental conditions and crew health on the station.
“The ultimate goal of the WetLab-2 system is to help humans live and work in space,” said Schonfeld. “This system will help researchers identify changes in gene expression. This can help us determine how to mitigate negative effects of spaceflight and add to our knowledge about how genes work.”
The WetLab-2 system was developed at Ames and funded by the International Space Station Program at NASA’s Johnson Space Center in Houston.
WetLab-2 launched April 8 aboard the eighth SpaceX cargo resupply mission to the space station. The goal of the first flight is to validate system performance. After successful completion of the validation study, WetLab-2 will be available to speed delivery of gene expression data to principal investigators on Earth for academic, commercial and NASA research.
The space station serves as the world's leading laboratory where researchers conduct cutting-edge research and technology development that will enable human and robotic exploration of destinations beyond low-Earth orbit, including asteroids and Mars.
NASA Marks Success for Most Complex Drone Traffic Management Test Yet at FAA Test Sites
In the first and largest demonstration of its kind, NASA and operators from the Federal Aviation Administration’s (FAA) unmanned aircraft systems (UAS) test sites across the country flew 22 drones simultaneously to assess rural operations of NASA’s UAS traffic management (UTM) research platform.
Operators outside NASA interacted with the UTM research platform, entering flight plans and planned operations from several geographically diverse locations, using various aircraft and software. The UTM research platform checked for conflicts, approved or rejected the flight plans and notified users of constraints. Engineers at NASA’s Ames Research Center in Silicon Valley, California, monitored operations and system load and gathered qualitative feedback to identify capability gaps to further refine the UTM research.
“We didn’t have any testing problems today,” said Parimal Kopardekar, manager of NASA’s Safe Autonomous Systems Operations project and lead of NASA’s UTM efforts. “NASA extensively tested Technical Capability Level one and worked very closely with the FAA test sites, and the UTM research platform performed well. This test would not have been possible without the six FAA test sites – it was a collaborative effort to ensure a successful test.”
A total of 24 drones flew multiple times throughout the three-hour test, with 22 flying simultaneously at one point. The mission was declared successful, given the minimum success criteria of 16 simultaneous operations was achieved. In addition to the live aircraft interacting with UTM, NASA Ames introduced dozens of virtual aircraft into the same airspace to further enhance the test. This mixing of live flights with virtual flights provided additional insight for future tests to refine the UTM concept.
Conducting a successful test required hours of coordination and logistics. Weather conditions at each of the test sites provided an additional challenge as drones cannot fly in rain or high winds, so engineers monitored weather conditions across the country to ensure the drones could fly. Winds are often greater in the afternoon, so the optimum flight window was 7 a.m. – 3 p.m. PDT. The forecast the prior day predicted a 40% chance of rain for two locations, but the weather cooperated, and all sites – Fairbanks, Alaska; Grand Forks, North Dakota; Reno, Nevada; Rome, New York; Virginia Tech’s locations in Blacksburg, Virginia, and Bushwood, Maryland; and Corpus Christi, Texas – flew during the test.
“After so much preparation and practice, it was very rewarding to see all test sites have success with weather, platforms and connectivity,” said Tony Basile, director of operations at NUAIR and New York test site manager. “It was additionally rewarding to hear from NASA that today’s efforts were successful on their end as well.”
Joseph Rios, flight test director and UTM technical lead explained, “NASA built the research platform and tested it on a local scale, but we needed the experience and expertise at each of the FAA test sites to exercise the platform in this geographically diverse way. Their efforts and skills in managing field deployments were pivotal to the success of this activity.”
Echoing that sentiment, Cathy Cahill, the director of the Alaska Center for Unmanned Aircraft Systems Integration in Fairbanks, said, “This mission demonstrated the technological advances that can be made when the expertise of NASA is combined with the capabilities of our nation’s UAS test sites.”
"We enjoyed working with the NASA UTM team to explore UAS air traffic management concepts through the UTM research platform,” said Richard C. Kelley, chief engineer for the Nevada Advanced Autonomous Systems Innovation Center at the University of Nevada, Reno. “The software performed wonderfully, providing much-needed data and pointing toward open questions for the research community to address as we work to safely integrate unmanned aircraft into the National Airspace System."
Each FAA test site determined how they wanted to interact with NASA’s UTM research platform. For example, the Northern Plains UAS test site from the North Dakota Department of Commerce used fixed wing aircraft from four different manufacturers, two of which built UTM software capabilities into their own ground control stations, while the other two used UTM software in their aircraft.
“We wanted to test UTM concepts across diverse implementation methods, and partnering with a number of local and regional companies was a key factor in our ability to do so, and our success today,” said Doug Olsen, principal investigator of the project at the University of North Dakota.
Many of the operators and test site employees remarked on the potential benefits of future systems that may leverage the results of this work.
“Using a traffic management framework to separate the aircraft and provide position awareness to air traffic control or to a mission commander helps us provide space between manned aircraft and unmanned aircraft, and actually promotes the safety of integrating those two into the airspace,” said Mathew Nelson, a UAS pilot at the Texas FAA test site.
“NASA is developing forward-thinking solutions to today’s aeronautical challenges with UAS,” said Rose Mooney, executive director of the Virginia Tech Mid-Atlantic Aviation Partnership.
UTM is still in the early research stages. This test of UTM Technical Capability Level one addressed rural UAS operations within line-of-site, such as could be potentially used for applications for agriculture, firefighting and power line monitoring. The UTM project has four technical capability levels, each increasing in complexity, culminating with level four – with potential applicability for high-density urban UAS operations. NASA is working closely with the FAA throughout the research process to define deliverables. NASA plans to turn over its UTM research to the FAA in 2019 for further testing.
This activity is sponsored by the Airspace Operations and Safety Program under NASA’s Aeronautics Research Mission Directorate. Four of NASA’s research centers – Ames, NASA’s Armstrong Flight Research Center in Edwards, California; Glenn Research Center in Cleveland; and Langley Research Center in Hampton, Virginia – are actively involved in the agency’s UTM initiative.
RELEASE 16-046 NASA Seeks Industry Ideas for an Advanced Mars Satellite
NASA is soliciting ideas from U.S. industry for designs of a Mars orbiter for potential launch in the 2020s. The satellite would provide advanced communications and imaging, as well as robotic science exploration, in support of NASA’s Journey to Mars.
The orbiter would substantially increase bandwidth communications and maintain high-resolution imaging capability. It also may use experimental cutting-edge technologies, such as high-power solar electric propulsion or an optical communications package, which could greatly improve transmission speed and capacity over radio frequency systems.
Under the direction of NASA’s Mars Exploration Program, the agency’s Jet Propulsion Laboratory (JPL) in Pasadena, California, is conducting pre-formulation planning for this possible orbiter mission. Pre-formulation plans include the procurement of industry studies for a solar-powered orbiting spacecraft. This effort seeks to take advantage of industry capabilities to improve deep space, solar electric propulsion-enabled orbiters to accommodate scientific instruments, demonstrate capability for rendezvous and capture, and advance telecommunications capabilities.
“Our success in exploring Mars, to unravel the mysteries of the Red Planet, depends on having high bandwidth communication with Earth and overhead imaging,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington. “Currently, we depend on our orbiting science missions to perform dual service in making measurements and acting as communication relays, but we can’t depend on them to last forever. This new orbiter will use cutting-edge technology to revitalize our ability to continue to explore Mars and support transformative science, including a potential sample return mission in the future.”
JPL plans to award concept study subcontracts of $400,000 per subcontract in June. The concept studies for the spacecraft will be completed over a four-month period.
In response to an earlier request from NASA, the Mars Exploration Program formed an analysis group that proposed, in a 2015 report, possible science objectives for a Mars orbiter capable of replenishing and advancing the telecommunications and reconnaissance resources available at Mars.
NASA is studying how to implement this mission concept in concert with its international partners to the greatest extent possible. Historically, there have been significant international contributions to NASA Mars missions that include the Curiosity rover, Mars Reconnaissance Orbiter spacecraft and the Mars Atmosphere and Volatile Evolution Mission orbiter, both currently orbiting the Red Planet. The agency will seek such partnerships for this potential future orbiter mission, as well.
NASA is on an ambitious journey to Mars that includes sending humans to the Red Planet, and that work remains on track. Robotic spacecraft are leading the way for the Mars Exploration Program, with current missions, in addition to the planned launch of the Insight lander in 2018, and the design and build of the Mars 2020 rover.
