Washington, Feb 10, 2017: NASA said its OSIRIS-REx spacecraft has started a two-week search for an enigmatic class of near-Earth objects known as Earth-Trojan asteroids.
The mission, currently on a two-year outbound journey to the asteroid Bennu, will spend almost two weeks searching for evidence of these small bodies, the US space agency said on Thursday.
Although scientists have discovered thousands of Trojan asteroids accompanying other planets, only one Earth-Trojan has been identified to date, asteroid 2010 TK7.
Scientists predict that there should be more Trojans sharing Earth’s orbit but they are difficult to detect from Earth as they appear near the sun on the Earth’s horizon.
“So this search gives us a unique opportunity to explore the primordial building blocks of Earth,” said principal investigator Dante Lauretta of the University of Arizona, Tucson.
Trojan asteroids are trapped in stable gravity wells, called Lagrange points, which precede or follow a planet.
Launched on September 8, 2016, OSIRIS-REx is currently travelling through Earth’s fourth Lagrange point, which is located 60 degrees ahead in Earth’s orbit around the sun, about 150 million km from Earth.
The mission team will use this opportunity to take multiple images of the area with the spacecraft’s MapCam camera in the hope of identifying Earth-Trojan asteroids in the region.
“Because the Earth’s fourth Lagrange point is relatively stable, it is possible that remnants of the material that built Earth are trapped within it,” Lauretta said.
The operations involved in searching for Earth-Trojan asteroids closely resemble those required to search for natural satellites and other potential hazards around Bennu when the spacecraft approaches its target in 2018, NASA said. (IANS)
Sue Finley, now 80 years old and NASA’s longest-serving female employee, recalls her early days with the space agency when she worked as a human “computer,” calculating rocket trajectories by hand at a time when computers were huge and expensive to operate.
Finley arrived at Jet Propulsion Laboratory (JPL) in Pasadena, California, in January 1958, one week before the U.S. Army launched Explorer 1, America’s first earth satellite.
“It was a very big deal,” she recalls of the launch, a response to the launches a few months earlier of the first satellites, Sputnik 1 and 2, from the former Soviet Union.
She was at JPL for Pioneer 1, the first satellite sent aloft by the newly formed National Aeronautics and Space Administration (NASA) in late 1958, which marked the beginning of the international space race.
Unmanned space probes
Since then, Finley has had a role in nearly every U.S. unmanned space probe, and some missions of other nations.
There were failures to overcome and spectacular successes, but always new goals as scientists expanded our knowledge of the earth and solar system.
“We were certainly proud,” she says of NASA accomplishments, “but you just go to the next thing.”
Finley has been through several career changes with the space agency, one of the most important when NASA phased out human computers, moving, initially, to simple electronic versions.
“We got little tiny computers,” she recalls. “One I had 16 wires, jumper cables to code with. One had 10 pegboards that you programmed with.”
As modern computers took over navigational tasks, Finley developed and tested software as a subsystem engineer.
Among her career highlights: the Vega mission, a Soviet-French collaboration with Venus, and Halley’s Comet, which received navigational help from NASA and dropped balloons into the atmosphere of Venus.
She had to change the software for the antenna that tracked the mission, “and it worked,” Finley recalls. “Everything worked. That’s what was so exciting!”
Finley has worked since 1980 on NASA’s Deep Space Network, which coordinates satellite facilities in California, Spain and Australia that allow communication with space probes.
Highlights of NASA career
Career highlights include developing software that generates audio tones sent back from spacecraft, informing engineers on the ground what is happening in space. It was first developed for the Mars missions.
Each tone has a meaning that communicates data, noted one of Finley’s colleagues, Stephen Lichten.
“If a parachute opened, it would send a tone,” Lichten, manager for special projects for the Deep Space Network, said.
“The spacecraft lets go of its heat shield, and it would send a different tone, and so engineers like Sue were here listening for those special frequencies which told them the spacecraft was telling them what it has just done,” he said.
He notes that Finley also helped develop communication arrays that combine multiple antennas to act in unison and other advances that now crucial to space missions.
Lichten once shared an office with Finley and says she inspired her younger colleagues.
“There was a parade of people coming in constantly, to ask her advice, to ask her questions,” he recalls. “This was during the Venus balloon mission days and I realized that Sue was regarded as sort of a guru at JPL.”
Finley has been involved with nearly every advance in space communications in recent decades, and she continues her work today, Lichten said.
There are many more women at NASA today than there were when she started, and Finley said she tells young women to be inquisitive.
“I tell them to never be afraid to ask questions, never be afraid to say you don’t know,” she said.
After nearly six decades at the space agency, a mother of two grown sons and a mentor to her colleagues, Finley has no plans of retiring.
“There’s nothing else I want to do,” she said. “And so far, they need me.”
As they have since the earliest days of the space agency. (VOA)
Florida, November 19, 2017: NASA captured 20 years of changing seasons on Earth in a striking new global map of the home planet.
The data visualization, released this week, shows Earth’s fluctuations as seen from space.
The polar ice caps and snow cover are shown ebbing and flowing with the seasons. The varying ocean shades of blue, green, red and purple depict the abundance — or lack — of undersea life.
“It’s like watching the Earth breathe. It’s really remarkable,” said NASA oceanographer Jeremy Werdell, who took part in the project.
Two decades — from September 1997 to this past September — are crunched into 2½ minutes of viewing.
Werdell finds the imagery mesmerizing. “It’s like all of my senses are being transported into space, and then you can compress time and rewind it, and just continually watch this kind of visualization,” he said Friday.
Werdell said the visualization shows spring coming earlier and autumn lasting longer in the Northern Hemisphere. Also noticeable to him is the receding of the Arctic ice caps over time — and, though less obvious, the Antarctic, too.
On the sea side, Werdell was struck by “this hugely productive bloom of biology” that exploded in the Pacific along the equator from 1997 to 1998 — when a water-warming El Nino merged into cooling La Nina. This algae bloom is evident by a line of bright green.
In considerably smaller Lake Erie, more and more contaminating algae blooms are apparent — appearing red and yellow.
All this data can provide resources for policymakers as well as commercial fishermen and many others, according to Werdell.
Programmer Alex Kekesi of NASA’s Goddard Space Flight Center in Maryland said it took three months to complete the visualization, using satellite imagery.
Just like our Earth, the visualization will continually change, officials said, as computer systems improve, new remote-sensing satellites are launched and more observations are made. (VOA)
Washington: The ozone hole over Antarctica shrank to its smallest peak since 1988, NASA said Thursday. The huge hole in Earth’s protective ozone layer reached its maximum this year in September, and this year NASA said it was 7.6 million square miles (19.6 million square kilometers). The hole size shrinks after mid-September.
This year’s maximum hole is more than twice as big as the United States, but it’s 1.3 million square miles smaller than last year and 3.3 million square miles smaller than 2015.
[ FILE – A false-color view of total ozone over the Antarctic pole is seen in this NASA handout image released Oct. 24, 2012. The purple and blue colors are where there is the least ozone. The average area covered by the Antarctic ozone hole in that year was the second smallest in two decades, at 8.2 million square miles; in September 2017, it was 7.6 million square miles ].
Paul Newman, chief Earth scientist at NASA’s Goddard Space Flight Center, said stormy conditions in the upper atmosphere warmed the air and kept the chemicals chlorine and bromine from eating ozone. He said scientists haven’t quite figured out why some years are stormier — and have smaller ozone holes — than others.
“It’s really small this year. That’s a good thing,” Newman said.
Newman said this year’s drop is mostly natural but is on top of a trend of smaller steady improvements likely from the banning of ozone-eating chemicals in a 1987 international treaty. The ozone hole hit its highest in 2000 at 11.5 million square miles (29.86 million square kilometers).
Ozone is a colorless combination of three oxygen atoms. High in the atmosphere, about 7 to 25 miles (11 to 40 kilometers) above the Earth, ozone shields Earth from ultraviolet rays that cause skin cancer, crop damage and other problems.
Scientists at the United Nations a few years ago determined that without the 1987 treaty, by 2030 there would have been an extra 2 million skin cancer cases. They said that overall, the ozone layer is beginning to recover because of the phase-out of chemicals used in refrigerants and aerosol cans. (VOA)