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[JPL] NASA Retires Kepler Space Telescope
« dnia: Październik 31, 2018, 10:54 »
NASA Retires Kepler Space Telescope
OCTOBER 30, 2018


NASA's Kepler space telescope, shown in this artist's concept, revealed that there are more planets than stars in the Milky Way galaxy. Image credit: NASA

After nine years in deep space collecting data that indicate our sky to be filled with billions of hidden planets - more planets even than stars - NASA's Kepler space telescope has run out of fuel needed for further science operations. NASA has decided to retire the spacecraft within its current, safe orbit, away from Earth. Kepler leaves a legacy of more than 2,600 planet discoveries from outside our solar system, many of which could be promising places for life.

"As NASA's first planet-hunting mission, Kepler has wildly exceeded all our expectations and paved the way for our exploration and search for life in the solar system and beyond," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate in Washington. "Not only did it show us how many planets could be out there, it sparked an entirely new and robust field of research that has taken the science community by storm. Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars."

Kepler has opened our eyes to the diversity of planets that exist in our galaxy. The most recent analysis of Kepler's discoveries concludes that 20 to 50 percent of the stars visible in the night sky are likely to have small, possibly rocky, planets similar in size to Earth, and located within the habitable zone of their parent stars. That means they're located at distances from their parent stars where liquid water - a vital ingredient to life as we know it - might pool on the planet surface.

The most common size of planet Kepler found doesn't exist in our solar system - a world between the size of Earth and Neptune - and we have much to learn about these planets. Kepler also found nature often produces jam-packed planetary systems, in some cases with so many planets orbiting close to their parent stars that our own inner solar system looks sparse by comparison.

"When we started conceiving this mission 35 years ago, we didn't know of a single planet outside our solar system," said the Kepler mission's founding principal investigator, William Borucki, now retired from NASA's Ames Research Center in California's Silicon Valley. "Now that we know planets are everywhere, Kepler has set us on a new course that's full of promise for future generations to explore our galaxy."

Launched on March 6, 2009, the Kepler space telescope combined cutting-edge techniques in measuring stellar brightness with the largest digital camera outfitted for outer space observations at that time. Originally positioned to stare continuously at 150,000 stars in one star-studded patch of the sky in the constellation Cygnus, Kepler took the first survey of planets in our galaxy and became the agency's first mission to detect Earth-size planets in the habitable zones of their stars.

"The Kepler mission was based on a very innovative design. It was an extremely clever approach to doing this kind of science," said Leslie Livesay, director for astronomy and physics at NASA's Jet Propulsion Laboratory, who served as Kepler project manager during mission development. "There were definitely challenges, but Kepler had an extremely talented team of scientists and engineers who overcame them."

Four years into the mission, after the primary mission objectives had been met, mechanical failures temporarily halted observations. The mission team was able to devise a fix, switching the spacecraft's field of view roughly every three months. This enabled an extended mission for the spacecraft, dubbed K2, which lasted as long as the first mission and bumped Kepler's count of surveyed stars up to more than 500,000.

The observation of so many stars has allowed scientists to better understand stellar behaviors and properties, which is critical information in studying the planets that orbit them. New research into stars with Kepler data also is furthering other areas of astronomy, such as the history of our Milky Way galaxy and the beginning stages of exploding stars called supernovae that are used to study how fast the universe is expanding. The data from the extended mission were also made available to the public and science community immediately, allowing discoveries to be made at an incredible pace and setting a high bar for other missions. Scientists are expected to spend a decade or more in search of new discoveries in the treasure trove of data Kepler provided.


"We know the spacecraft's retirement isn't the end of Kepler's discoveries," said Jessie Dotson, Kepler's project scientist at NASA's Ames Research Center in California's Silicon Valley. "I'm excited about the diverse discoveries that are yet to come from our data and how future missions will build upon Kepler's results."

Before retiring the spacecraft, scientists pushed Kepler to its full potential, successfully completing multiple observation campaigns and downloading valuable science data even after initial warnings of low fuel. The latest data, from Campaign 19, will complement the data from NASA's newest planet hunter, the Transiting Exoplanet Survey Satellite, launched in April. TESS builds on Kepler's foundation with fresh batches of data in its search of planets orbiting some 200,000 of the brightest and nearest stars to the Earth, worlds that can later be explored for signs of life by missions such as NASA's James Webb Space Telescope.

NASA's Ames Research Center manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation in Boulder, Colorado, operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

For the Kepler press kit, which includes multimedia, timelines and top science results, visit:

https://www.nasa.gov/kepler/presskit

For more information about the Kepler mission, visit:

https://www.nasa.gov/kepler

Source: NASA Retires Kepler Space Telescope

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Odp: [JPL] NASA Retires Kepler Space Telescope
« Odpowiedź #1 dnia: Listopad 03, 2018, 10:46 »
NASA’s trailblazing Kepler telescope ends planet hunt
October 30, 2018 Stephen Clark


This illustration depicts NASA’s exoplanet hunter, the Kepler space telescope. Credits: NASA/Wendy Stenzel/Daniel Rutter

NASA’s Kepler telescope has run out of fuel and ended science operations, closing out a pioneering decade-long mission that showed planets are commonplace across our galaxy, agency officials said Tuesday.

The observatory’s supply of hydrazine has run low for months, but controllers noticed a dramatic drop in fuel pressure earlier this month, indicating Kepler no longer has enough propellant to maintain the precise pointing required to search for planets around other stars, or exoplanets.

Kepler’s observations since its launch in March 2009 have led astronomers to confirm the existence of 2,681 planets orbiting other stars, with another 2,899 planet candidates in the pipeline that could be confirmed with follow-up observations.

“In 2009, the Kepler mission launched, and immediately our team began detecting a wide variety of planets,” said Bill Borucki, a retired astronomer who led Kepler’s science team through development and its early years of science observations. “In its nine-and-a-half years of operation, the Kepler mission has been an enormous success.

“We’ve shown that there are more planets than stars in our galaxy, that many of these planets are roughly the size of the Earth, and some, like the Earth, are at the right distance from their star so there could be liquid water on their surface, a situation conducive to the existence of life,” Borucki said.

Astronomers discovered a variety of planet types with Kepler, ranging from so-called “hot Jupiters” to “super Earths,” and a handful of rocky planets believed to reside at the right distance from their parent star to maintain liquid water.

“Hot Jupiters” are gas giants that orbit hellishly close to their stars, often completing one lap in a matter of days with surface temperatures above 2,000 degrees Fahrenheit (1,100 degrees Celsius).


NASA’s Kepler space telescope at the Astrotech spacecraft processing facility in Florida before its launch on a Delta 2 rocket in 2009. Credit: NASA

Kepler also found numerous planets between the size of Earth and Neptune. Such planets that orbit the right distance from their star could be water-rich and habitable, astronomers say.

“We’ve also discovered planets completely unlike those in our solar system,” Borucki said Tuesday. “Some of those, in fact, might be worlds of water — actual water worlds. We’ve also found planets that were formed at the beginning of our galaxy, six-and-a-half billion years before the formation of our own star and the before the formation of the Earth. Imagine what life might be like on such planets.”

Scientists said Kepler’s observations yielded the discovery of between 2 and 12 near-Earth size planets in the habitable zone of their stars, according to NASA.

“Because of Kepler, we know that planets are an incredibly diverse set of objects, much more diverse than we observe in our own solar system,” said Paul Hertz, director of NASA’s astrophysics division. “And because of Kepler, we know that solar systems come in a variety of configurations unlike our own.”

Borucki summed it up: “In a sense, our planetary system is quite atypical.”

Kepler was NASA’s first space mission dedicated to the search for planets around other stars.

Borucki, who retired from NASA in 2015 after 53-year career, started working on a planet-hunting telescope mission in 1983, nine years before astronomers even confirmed the discovery of the first exoplanet with ground-based observatories. His concept focused on using an ultra-sensitive instrument — using an array of light-detecting sensors called photometers coupled with a telescope — to monitor the brightness of stars and register faint dips in light when planets pass in front of their stars.

The technique is called the “transit method” for finding exoplanets, and it tells scientists about the size of each world, which can lead astronomers to infer whether the planet is a gaseous object or a rocky one.

Based at NASA’s Ames Research Center in California, Borucki and his team worked on the photometer technology in labs and on ground-based telescopes until NASA selected his Kepler proposal for full development in 2001.

Speaking with reporters Tuesday, Borucki likened Kepler’s technological achievement to “trying to detect a fly crawling across a car headlight when the car was 100 miles away. And the instrument must do it for 150,000 stars simultaneously.”


President Barack Obama congratulates William Borucki on receiving the Samuel J. Heyman Service to America Medal, or Sammie, in the East Room of the White House. Credit: Official White House Photo by Pete Souza

Built by Ball Aerospace, the Kepler spacecraft launched from Cape Canaveral on March 6, 2009, aboard a United Launch Alliance Delta 2 rocket. The launcher deployed Kepler into an Earth-trailing orbit around the sun, and the spacecraft has distanced itself from its home planet over its nearly decade-long mission, now located around 94 million miles (151 million kilometers) from Earth, according to Charlie Sobeck, Kepler’s project system engineer at Ames.

During Kepler’s four-year primary mission — from the observatory’s launch in March 2009 until early 2013 — the craft aimed its telescope at the same field of more than 150,000 stars in the constellations Cygnus and Lyra.

The 2013 failure of a second of four reaction wheels used to keep Kepler’s 3.1-foot (95-centimeter) telescope pointed prompted engineers to re-plan the mission. An extended observations campaign dubbed K2 began in 2014, using a combination of the two remaining reaction wheels, hydrazine fuel and solar pressure to maintain the telescope’s aim at a new star field every few months.

Kepler launched with 12 kilograms, or a little over 3 gallons, of hydrazine fuel feeding rocket thrusters to occasionally unload momentum from the observatory’s spinning gyro-like reaction wheels and offset solar pressure that could influence the spacecraft’s orientation.

“We knew when we launched that the spacecraft would ultimately be limited by its fuel load,” Sobeck said.

Sobeck said Kepler operated more than twice its original design life, and ground controllers first noticed signs of Kepler’s waning fuel supply in June as telemetry measurements showed pressures dropping in the spacecraft’s propulsion system.

“Because of fuel exhaustion, the Kepler spacecraft has reached the end of its service life,” Sobeck said. “While this may be a sad event, we are by no means unhappy with the performance of this marvelous machine.”

Sobeck said controllers will send the final command to Kepler in the coming weeks, ordering the spacecraft to disable its on-board fault protection software and turn off its transmitters.

Kepler collected its last science observations in September, ending a run that observed more than 530,000 stars and returned 678 gigabytes of data. Kepler’s discoveries also helped astronomers write nearly 3,000 scientific papers, a number that will continue to climb.


Artist’s concept of Kepler-16b, first planet around a double-star system Credits: NASA/JPL-Caltech/T. Pyle

“We found small potentially rocky planets around some of these bright stars, and those are now prime targets of current and future telescopes so we can move on to see what these planets are made of, how they are formed, and what their atmospheres be like,” said Jessie Dotson, Kepler project scientist at Ames.

“While we have ceased spacecraft operations, the science results from the Kepler data will continue for years to come,” she said.

A NASA spokesperson said the Kepler mission cost $692 million, including its development, launch and operations.

“I always felt like it was the little spacecraft that could,” Dotson said. “It always did what we asked of it, and sometimes more, and that’s a great thing to have from a spacecraft.”

“This marks the formal end of data collection, but not the end of data analysis thanks to NASA’s public archives,” tweeted Natalie Batalha, an astrophysicist and former Kepler project scientist. “I’m not sad.  We did everything we wanted and more. Onward!”

NASA’s Transiting Exoplanet Survey Satellite launched in April to extend Kepler’s search across nearly the entire sky over a two-year prime mission. TESS will use the same “transit” search method as Kepler, but will focus on bright, nearby stars.

“NASA is handing off the mantle of planet-hunter from the Kepler space telescope to TESS — the Transiting Exoplanet Survey Satellite — which is already in orbit and is discovering new exoplanets even as we speak,” Hertz said.

The long-delayed James Webb Space Telescope, now set for launch in 2021, will have the power to probe many of the planets discovered by Kepler and TESS and study the make-up of their atmospheres.

“The planets that TESS can find, we are hoping to put the next layer of information on those and determine what those planets are like as places,” said Padi Boyd, TESS project scientist at NASA’s Goddard Space Flight Center in Maryland. “It’s easy to measure the size of a planet — comparatively easy — but it’s much, much harder to be able to tell if that planet has an atmosphere, which is so important to life here on Earth. And if it does have an atmosphere, what does it contain? Does it contain water, which we believe is an essential building block for life?”

Source: NASA’s trailblazing Kepler telescope ends planet hunt

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Odp: [JPL] NASA Retires Kepler Space Telescope
« Odpowiedź #2 dnia: Listopad 19, 2018, 00:00 »
Kepler Telescope Bids 'Goodnight' with Final Commands
NOVEMBER 16, 2018 [JPL]


NASA's Kepler space telescope discovered thousands of planets outside our solar system, and revealed that our galaxy contains more planets than stars. Credit: CNASAredit: NASA Ames/JPL-Caltech

On the evening of Thursday, Nov. 15, NASA's Kepler space telescope received its final set of commands to disconnect communications with Earth. The "goodnight" commands finalize the spacecraft's transition into retirement, which began on Oct. 30 with NASA's announcement that Kepler had run out of fuel and could no longer conduct science.

Coincidentally, Kepler's "goodnight" falls on the same date as the 388-year anniversary of the death of its namesake, German astronomer Johannes Kepler, who discovered the laws of planetary motion and passed away on Nov. 15, 1630.

<a href="http://www.youtube.com/watch?v=cwDkPKPi1mY" target="_blank">http://www.youtube.com/watch?v=cwDkPKPi1mY</a>
https://www.youtube.com/watch?v=cwDkPKPi1mY

The Kepler space telescope has had a profound impact on our understanding of the number of worlds that exist beyond our solar system. Through its survey, we've discovered there are more planets than stars in our galaxy. As a farewell to the spacecraft, we asked some of people closest to Kepler to reflect on what Kepler has meant to them and its finding of "more planets than stars."

The final commands were sent over NASA's Deep Space Network from Kepler's operations center at the Laboratory for Atmospheric and Space Physics, or LASP, at the University of Colorado in Boulder. LASP runs the spacecraft's operations on behalf of NASA and Ball Aerospace & Technologies Corporation in Boulder, Colorado.

Kepler's team disabled the safety modes that could inadvertently turn systems back on, and severed communications by shutting down the transmitters. Because the spacecraft is slowly spinning, the Kepler team had to carefully time the commands so that instructions would reach the spacecraft during periods of viable communication. The team will monitor the spacecraft to ensure that the commands were successful. The spacecraft is now drifting in a safe orbit around the Sun, 94 million miles away from Earth.

The data Kepler collected over the course of more than nine years in operation will be mined for exciting discoveries for many years to come.

NASA's Ames Research Center in California's Silicon Valley manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from LASP.

For the Kepler press kit, which includes multimedia, timelines and top science results, visit:

https://www.nasa.gov/kepler/presskit

For more information about the Kepler mission, visit:

https://www.nasa.gov/kepler

Source: Kepler Telescope Bids 'Goodnight' with Final Commands