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NASA’s Kepler Mission
Posted: 09 April 2009 06:37 PM   [ Ignore ]   [ # 31 ]
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http://kepler.nasa.gov/about/news.html

“2009 April 8. Mission Manager Update - The dust cover was successfully jettisoned from the front of the telescope last evening at about 7:18 p.m. PDT. Everything went according to prediction, with the vehicle experiencing a slight push to one side. Kepler’s attitude control system easily responded to the movement, steering the spacecraft back to its original position.

“Starlight was seen in all four of the fine guidance sensors on the corners of the photometer focal plane (the area where light is focused). The spacecraft was maneuvered to the science attitude, or the position where it will collect science data. It will collect images as the temperatures drop to operational range. The next several days will be spent calibrating the alignment of the fine guidance sensors with the spacecraft star trackers, and achieving fine point using the fine guidance sensors. This will enable the spacecraft to stabilize the line of sight at levels similar to the performance of NASA’s Hubble Space Telescope.

“April 8 14:00 UTC - Distance to Kepler: 3,153,000 km; 1,959,000 mi; 0.021 AU; 8.20 times the distance to the Moon.”

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Posted: 11 April 2009 10:55 PM   [ Ignore ]   [ # 32 ]
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The Kepler Mission is readying itself to begin its photographic program.  The equipment used for this purpose is outlined below with photograph appended. 

Photometer and Spacecraft

The Kepler photometer is a simple single purpose instrument. It is basically a Schmidt telescope design with a 0.95-meter aperture and a 105 deg2 (about 12 degree diameter) field-of-view (FOV). It is pointed at and records data from just a single group of stars for the four year duration of the mission.

The photometer is composed of just one “instrument,” which is, an array of 42 CCDs (charge coupled devices). Each 50x25 mm CCD has 2200x1024 pixels. The CCDs are read out every three seconds to prevent saturation. Only the information from the CCD pixels where there are stars brighter than mv=14 is recorded. (The CCDs are not used to take pictures. The images are intentionally defocused to 10 arc seconds to improve the photometric precision.) The data are integrated for 30 minutes.

The Kepler Photometer
The instrument has the sensitivity to detect an Earth-size transit of an mv=12 G2V (solar-like) star at 4 sigma in 6.5 hours of integration. The instrument has a spectral bandpass from 400 nm to 850 nm. Data from the individual pixels that make up each star of the 100,000 main-sequence stars brighter than mv=14 are recorded continuously and simultaneously. The data are stored on the spacecraft and transmitted to the ground about once a week.

Photometer Mounted on the Spacecraft
The spacecraft provides the power, pointing and telemetry for the photometer. Pointing at a single group of stars for the entire mission greatly increases the photometric stability and simplifies the spacecraft design. Other than the small reaction wheels used to maintain the pointing and an ejectable cover, there are no other moving or deployable parts The only liquid is a small amount for the thrusters which is kept from slosh by a pressurized membrane. This design enhances the pointing stability and the overall reliability of the spacecraft.

Drawings of the spacecraft and its payload and onboard controls can be found at: http://kepler.nasa.gov/sci/design/spacecraft.html

[ Edited: 11 April 2009 11:05 PM by Fat Man ]
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Posted: 16 April 2009 05:54 PM   [ Ignore ]   [ # 33 ]
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Kepler Activated - First Images of Rocky Planets Come in to NASA

http://www.comcast.net/articles/news-science/20090416/SCI.Planet.Hunter/
Planet-hunting spacecraft’s first images released
5 hours ago

PASADENA, Calif. — NASA’s new planet-hunting telescope has beamed back the first images of a patch of faraway sky in the Milky Way galaxy where it hopes to find Earth-like planets. NASA on Thursday released several images snapped by Kepler earlier this month, including a view of a distant part of our galaxy containing some 14 million stars. Scientists say more than 100,000 of those stars are potential candidates for research.

Kepler was launched in March and will spend 3 1/2 years studying these stars in search of small rocky planets.

The $600 million mission will begin searching after engineers tune up Kepler’s science instruments in the next few weeks.

[ Edited: 16 April 2009 05:56 PM by Fat Man ]
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Posted: 17 April 2009 07:44 AM   [ Ignore ]   [ # 34 ]
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NASA’s Kepler Captures First Views of Planet-Hunting Territory

PASADENA, Calif.—NASA’s Kepler mission has taken its first images of the star-rich sky where it will soon begin hunting for planets like Earth.

The new “first light” images show the mission’s target patch of sky, a vast starry field in the Cygnus-Lyra region of our Milky Way galaxy. One image shows millions of stars in Kepler’s full field of view, while two others zoom in on portions of the larger region. The images can be seen online at:
NASA News Release:
http://www.nasa.gov/home/hqnews/2009/apr/HQ_09-085_Kepler_First_Light.html

http://www.nasa.gov/mission_pages/kepler/multimedia/20090416.html

“Kepler’s first glimpse of the sky is awe-inspiring,” said Lia LaPiana, Kepler’s program executive at NASA Headquarters in Washington. “To be able to see millions of stars in a single snapshot is simply breathtaking.”

One new image from Kepler shows its entire field of view—a 100-square-degree portion of the sky, equivalent to two side-by-side dips of the Big Dipper. The regions contain an estimated 14 millions stars, more than 100,000 of which were selected as ideal candidates for planet hunting.

Two other views focus on just one-thousandth of the full field of view. In one image, a cluster of stars located about 13,000 light-years from Earth, called NGC 6791, can be seen in the lower left corner. The other image zooms in on a region containing a star, called Tres-2, with a known Jupiter-like planet orbiting every 2.5 days.

“It’s thrilling to see this treasure trove of stars,” said William Borucki, science principal investigator for Kepler at NASA’s Ames Research Center at Moffett Field, Calif. “We expect to find hundreds of planets circling those stars, and for the first time, we can look for Earth-size planets in the habitable zones around other stars like the sun.”

Photo Caption:

This image zooms into a small portion of Kepler’s full field of view—an expansive, 100-square-degree patch of sky in our Milky Way galaxy. At the center of the field is a star with a known “hot Jupiter” planet, named “TrES-2,” zipping closely around it every 2.5 days. Kepler will observe TrES-2 and other known planets as a test to demonstrate that it is working properly, and to obtain new information about those planets.

The area pictured is one-thousandth of Kepler’s full field of view, and shows hundreds of stars at the very edge of the constellation Cygnus. The image has been color-coded so that brighter stars appear white, and fainter stars, red. It is a 60-second exposure, taken on April 8, 2009, one day after the spacecraft’s dust cover was jettisoned.

Kepler was designed to hunt for planets like Earth. The mission will spend the next three-and-a-half years staring at the same stars, looking for periodic dips in brightness. Such dips occur when planets cross in front of their stars from our point of view in the galaxy, partially blocking the starlight.

To achieve the level of precision needed to spot planets as small as Earth, Kepler’s images are intentionally blurred slightly. This minimizes the number of saturated stars. Saturation, or “blooming,” occurs when the brightest stars overload the individual pixels in the detectors, causing the signal to spill out into nearby pixels.

Image credit: NASA/JPL-Caltech

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Posted: 20 April 2009 05:30 PM   [ Ignore ]   [ # 35 ]
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Some more information about Kepler:

2 / 14
The Milky Way, showing our sun about 25,000 light years from the galaxy’s centre. The yellow cone illustrates the region or ‘starfield’ in which Kepler will hunt for habitable planets
Photograph: Jon Lomberg/Nasa

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Posted: 20 April 2009 05:32 PM   [ Ignore ]   [ # 36 ]
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Kepler: more about the process.

When a planet passes in front of its sun this causes a mind-bogglingly tiny change in the star’s overall brightness. “If Kepler were to look down at a small town on Earth at night from space, it would be able to detect the dimming of a porch light as somebody passed in front,” says James Fanson, project manager at Nasa’s Jet Propulsion Laboratory in California. An orbiting planet will produce a regular, periodic change in the brightness of its star
Photograph: Nasa

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Posted: 21 April 2009 04:49 AM   [ Ignore ]   [ # 37 ]
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What struck me, after the adventures of Hubble, is that that Kepler’s optics have been left slightly out of focus, and that that’s by design: the telescope’s there to monitor light levels, not shapes.

Relatively raw image:
329144main_fullFFIHot300-516.jpg

Jazzed-up-for-the-public image:
ffi04132009hot300yellow_95-566.jpg

Sometimes the gutter between the individual detectors (rectangles) is slightly bigger than other times.  That too is by design.  There are bright stars in the foreground there that would obscure that area of view. Kepler has been positioned just right so the brightest stars don’t glare all over the place.

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Posted: 04 May 2009 06:56 PM   [ Ignore ]   [ # 38 ]
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Kepler Mission News and Schedule

Jim Fanson, Kepler,
JPL Project Manager

2009 May 1. Mission Manager Update - Kepler’s calibration data collection is drawing to a close. Several hundred data sets have been acquired to characterize and map the optical and noise performance of the telescope and the electronics for the focal plane array (the area where light is focused). The data sets are now being analyzed on the ground. Optimally shaped “windows” of pixels will be defined for each of the more than 100,000 target stars and a table of these pixels uploaded to the spacecraft. These are the pixels that will ultimately help the science team find planets—the pixels will be downlinked to Earth and used to construct light curves, or measurements of brightness over time, for each star.

After science observations begin, the data analysis “pipeline” at the Science Operations Center at NASA’s Ames Research Center in Moffett Field, Calif., will process the light curves to identify “threshold crossing events,” which is the first step in identifying potential transiting planets. Various tests will be applied to these events to weed out false indications. Once confidence is built for candidate transits, observations by ground-based telescopes will be performed to further rule out phenomena that can masquerade as transiting planets.

2009 May 01 14:00 UTC - Distance to Kepler: 5,382,000 km; 3,344,000 mi; 0.036 AU; 14.00 times the distance to the Moon.
2009 April 30 14:00 UTC - Distance to Kepler: 5,277,000 km; 3,279,000 mi; 0.035 AU; 13.73 times the distance to the Moon.
2009 April 29 14:00 UTC - Distance to Kepler: 5,173,000 km; 3,214,000 mi; 0.035 AU; 13.46 times the distance to the Moon.
2009 April 28 14:00 UTC - Distance to Kepler: 5,069,000 km; 3,150,000 mi; 0.034 AU; 13.19 times the distance to the Moon.
2009 April 27 14:00 UTC - Distance to Kepler: 4,966,000 km; 3,086,000 mi; 0.033 AU; 12.92 times the distance to the Moon.
2009 April 26 14:00 UTC - Distance to Kepler: 4,863,000 km; 3,022,000 mi; 0.033 AU; 12.65 times the distance to the Moon.
2009 April 25 14:00 UTC - Distance to Kepler: 4,762,000 km; 2,959,000 mi; 0.032 AU; 12.39 times the distance to the Moon.
2009 April 24 14:00 UTC - Distance to Kepler: 4,661,000 km; 2,896,000 mi; 0.031 AU; 12.13 times the distance to the Moon.
2009 April 23. Mission Manager Update - The Kepler telescope’s focus has been successfully optimized. This involved moving the primary mirror of the telescope toward the focal plane array, the area where light is focused, by 40 microns (1.6 thousandths of an inch) and tilting it by 0.0072 degrees. Various other calibrations are underway, including: detailed measurement of star images formed by the telescope at various locations on the focal plane; determination of the exact sky coordinates of every one of the camera’s 95 million pixels, and mapping of “ghost” images, which result when the light from bright stars reflects off the front of the camera’s charge-coupled devices (CCDs), bounces off lenses inside the telescope, and winds up back on the CCDs in another location.
2009 April 23 14:00 UTC - Distance to Kepler: 4,561,000 km; 2,834,000 mi; 0.03 AU; 11.87 times the distance to the Moon.

2009 April 22 14:00 UTC - Distance to Kepler: 4,461,000 km; 2,772,000 mi; 0.03 AU; 11.61 times the distance to the Moon.
2009 April 21 14:00 UTC - Distance to Kepler: 4,363,000 km; 2,711,000 mi; 0.029 AU; 11.35 times the distance to the Moon.
2009 April 20. Mission Manager Update - The Kepler science team has decided that further refinement of the telescope’s focus would significantly improve the mission’s science return. The project is therefore proceeding with these adjustments. The telescope’s 1.4-meter (55-inch) primary mirror rests on three displacement actuators, much like a three-legged stool. The actuators can be commanded to extend or contract in tiny steps to adjust the mirror in tip, tilt and piston. This adjusts the position of the optical focal surface, the area where light is first focused, relative to the focal plane array, where the imaging detectors are located. An optimized focus of the telescope would make the image quality more uniform across the field of view and minimize the number of imaging pixels required to measure each target star. This would permit more stars to be monitored with less measurement noise, and result in the planet search being more sensitive to smaller planets.
2009 April 20 14:00 UTC - Distance to Kepler: 4,265,000 km; 2,651,000 mi; 0.029 AU; 11.10 times the distance to the Moon.

2009 April 19 14:00 UTC - Distance to Kepler: 4,169,000 km; 2,590,000 mi; 0.028 AU; 10.85 times the distance to the Moon.
2009 April 18 14:00 UTC - Distance to Kepler: 4,073,000 km; 2,531,000 mi; 0.027 AU; 10.60 times the distance to the Moon.
2009 April 17 14:00 UTC - Distance to Kepler: 3,978,000 km; 2,472,000 mi; 0.027 AU; 10.35 times the distance to the Moon.


Kepler Field of View Star Chart and
Animation: Optical Path for the Kepler Photometer

http://kepler.nasa.gov/about/1stlight/index.html

[ Edited: 04 May 2009 06:59 PM by Fat Man ]
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Posted: 29 May 2009 09:25 PM   [ Ignore ]   [ # 39 ]
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Kepler Mission Manager Update 05.29.09
Roger Hunter, Kepler-Ames Mission Manager Kepler remains safe and stable in its “drift-away” heliocentric orbit. The spacecraft is over 8.4 million kilometers from Earth. Kepler has been collecting science data since 12 May. The operations team has had nearly daily contacts using the Deep Space Network to check the spacecraft health. Science data collection is, by design, a very quiet period as the scientists want the spacecraft as stable as possible. Other than the continual collection of science data with Kepler’s photometer, the only activities that occur on the spacecraft, on a regular basis, are reaction wheel desaturations. These desaturations occur about every 3 days.

The orientation of the spacecraft (keeping the telescope pointed at the science field of view) is controlled by reaction wheels which slowly spin up to counter pressure from solar wind. Before any given wheels spin too fast, thrusters are fired to negate the momentum imparted to the spacecraft from the spin-up of the reaction wheels. The reaction wheel speeds are returned to near-zero, and the cycle begins again. We have loaded a command sequence on-board the spacecraft to execute these desaturations.

Meanwhile, scientists at NASA Ames Research Center are continuing their analysis of the instrument calibration data taken during Kepler’s commissioning phase. The data are of very high quality and the scientists are very pleased with the precision of the data. Hundreds of eclipsing binaries and variable stars were seen in this data.

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Posted: 26 November 2009 11:20 AM   [ Ignore ]   [ # 40 ]
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Kepler’s planetary discoveries thus far:

AlanBoss-PlanetDistro.jpg

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