Starship Asterisk*

On May 28, 2013, NASA's Kepler mission delivered new data to the NASA Exoplanet Archive.

Over the next week, the team will attempt tests to explore recovery of the spacecraft's reaction wheels. The tests will begin with reaction wheel 4 on Thursday, July 18, 2013.

The team anticipates continuing exploratory tests on reaction wheel 2 on Monday, July 22, 2013 or Thursday, July 25, 2013.

Results of the wheel performance tests will be known later this month and an update will follow.

On Thursday, July 18, 2013 the team initiated exploratory recovery tests on the spacecraft's two failed wheels. The recovery tests are a series of steps to characterize the performance of Reaction Wheels (RW) 4 and 2, and to determine if either could be returned to operation.

The initial test began on Thursday, July 18, 2013, with RW4. In response to test commands, wheel 4 did not spin in the positive (or clockwise) direction but the wheel did spin in the negative (or counterclockwise) direction. Wheel 4 is thought to be the more seriously damaged of the two.

On Monday, July 22, 2013, the team proceeded with a test of RW2. Wheel 2 responded to test commands and spun in both directions.

Over the next two weeks, engineers will review the data from these tests and consider what steps to take next. Although both wheels have shown motion, the friction levels will be critical in future considerations. The details of the wheel friction are under analysis.

Kepler requires extremely precise pointing to detect the faint periodic dimming of distant starlight— the telltale sign of a planet transiting the face of its host star. Too much friction from the reaction wheels can cause vibration and impact the pointing precision of the telescope.

The team has continued exploratory recovery testing of Reaction Wheel 4 (RW4). On Thursday, July 25, 2013, the wheel spun in both directions in response to commands.

While both RW4 and RW2 have spun bi-directionally, friction levels remain higher than would be considered good for an operational wheel. However, it will be important to characterize the stability of the friction over time. A constant friction level may be correctable in the spacecraft’s attitude control system, whereas a variable friction level will likely render the wheels unusable.

With the demonstration that both wheels will still move, and the measurement of their friction levels, the functional testing of the reaction wheels is now complete. The next step will be a system-level performance test to see if the wheels can adequately control spacecraft pointing.

The team is preparing for the next test using RW2. Friction levels on RW4, the wheel that failed in May, are higher and no additional testing is planned at this time. The pointing test involves determining the performance of the wheel as part of the spacecraft system. The test will be conducted in three stages.

The first stage of the pointing test will determine if the spacecraft can sustain coarse-point mode using RW1, 2 and 3. Coarse-point mode is regularly used during normal operations, but has insufficient pointing accuracy to deliver the high-precision photometry necessary for exoplanet detection. During coarse-point the star trackers measure the pointing accuracy of the spacecraft. When using wheels to control the spacecraft, pointing is typically controlled to within an arcsecond, with a fault declared if the pointing error exceeds a quarter of a degree. This degree of pointing accuracy would be equivalent to keeping an imaginary Kepler telescope pointed at a theatre-size movie screen in New York City's Central Park from San Francisco.

In the first stage, testing will demonstrate whether or not operation with RW2 can keep the spacecraft from entering safe mode. A safe mode is a self-protective measure that the spacecraft takes when an unexpected event occurs, such as elevated friction levels in the wheels.

In the second stage, testing will investigate RW2's ability to help control the spacecraft pointing with enough accuracy to transmit science data to the ground using NASA's Deep Space Network. If RW2 can sustain coarse-point in stage 1, the second stage of the test will be to point the high-gain antenna to Earth and downlink the data currently stored aboard. This requires that the pointing be controlled more tightly than simply avoiding safe mode, yet does not require the very fine control needed to return to science data collection.

The final stage of the test will determine if RW2 can achieve and maintain fine-point, the operating mode for collecting science data. During fine-point the fine-guidance sensors measure the spacecraft pointing. When using wheels to control the spacecraft, pointing is controlled to within a few milliarcseconds. Using our imaginary Kepler telescope example, this degree of pointing accuracy would be equivalent to pointing at a soccer ball in New York City's Central Park from San Francisco.

The team anticipates beginning the pointing performance testing on Thursday, August 8, 2013 and will continue into the following week if all goes well. A determination of whether Kepler can return to exoplanet data collection is expected a couple weeks after these pointing tests are complete.

As engineers explore recovery of the spacecraft, scientists continue to analyze the existing data. Earlier this week the team delivered their findings for 1,236 new Kepler Objects of Interest (KOIs) to the NASA Exoplanet Archive. The new KOIs were found by searching the observational data from Quarters 1 to Quarter 12. Of the 1,236 new KOIs, 274 were judged to be planet candidates, while many others were determined to be false positives. These newly announced Kepler planet candidates bring the current count to 3,548. Some of these new planet candidates are small and some reside in the habitable zone of their stars, but much work remains to be done to verify these results.

Also announced this week is the Kepler Science Conference II Nov. 4-8, 2013 at NASA Ames Research Center at Moffett Field, Calif. Registration is now open.

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Kepler Science Conference II

We are happy to announce that registration for the Kepler Science Conference II, held Nov. 4-8, 2013 at the NASA Ames Research Center at Moffett Field, Calif., is now open. Scientists, post-docs, and students are encouraged to attend and share in the presentation, discussion, and celebration of the latest scientific discoveries made by NASA's Kepler Mission.

• Main Conference Site
• Registration Information
  (Registration Closed: Oct. 18)
• Speaker Information and Abstract Submission
  (Abstract Deadline: Sept. 6)

This conference will highlight the full range of scientific results emerging from more than three years of Kepler observations, as well as what to expect from continued observations.

Topics to be covered include:

• Exoplanet Statistics, False Positives, and Completeness Corrections
• Earth Analogues and Super-Earths
• Multiple Planets and Multiple Star Systems
• Planet Formation and Migration Theories
• Habitable Zone
• Characterizing Transiting Planets
• Stellar Activity, Rotation, Ages, Metallicity
• Eclipsing and Interacting Binaries
• Future Exoplanet Telescopes and Instrumentation
• Asteroseismology
• Galactic and Extragalactic Astrophysics

There is no registration fee for this conference, however all attendees must register through the online registration site.

http://en.wikipedia.org/wiki/Kepler_%28spacecraft%29#Mission_status wrote:
<<Possible future uses [for Kepler] include searching for asteroids and comets, looking for evidence of supernovas, and finding huge exoplanets through gravitational microlensing. Another proposal is to modify the software on Kepler to compensate. Instead of the stars being fixed and stable in Kepler's field of view, they will drift. However, software could track this drift and more or less completely recover the mission goals despite being unable to hold the stars in a fixed view.>>

neufer wrote:

http://en.wikipedia.org/wiki/Kepler_%28spacecraft%29#Mission_status wrote:
<<Possible future uses [for Kepler] ...Another proposal is to modify the software on Kepler to compensate. Instead of the stars being fixed and stable in Kepler's field of view, they will drift. However, software could track this drift and more or less completely recover the mission goals despite being unable to hold the stars in a fixed view.>>

http://en.wikipedia.org/wiki/Kepler_%28spacecraft%29#Mission_status wrote:

<<Possible future uses [for Kepler] include searching for asteroids and comets,
looking for evidence of supernovas, and finding huge exoplanets through gravitational microlensing.>>

http://kepler.nasa.gov/mission/faq/ wrote:
<<Kepler is in an “earth-trailing” orbit, taking 371 days to orbit the Sun. After 61 years, it will be in the vicinity of the Earth, but not collide. Mission Principal Investigator Bill Borucki says “My grandchildren will retrieve Kepler, and place it in the new National Air and Space Museum on the Moon!”>>

http://www.computerworld.com/s/article/9241791/NASA_revives_mothballed_spacecraft_to_be_asteroid_hunter wrote:

[b][color=#0000FF]An artist's depiction of WISE, a NASA spacecraft, which is being brought out of retirement to hunt for asteroids. (Image: NASA)[/color][/b]

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NASA revives mothballed spacecraft to be asteroid hunter
WISE spacecraft will search for near-Earth asteroids
By Sharon Gaudin, Computerworld, August 22, 2013

<<The Wide-field Infrared Survey Explorer (WISE) worked from January 2010 to February 2011, hunting for and characterizing tens of thousands of asteroids throughout the solar system. Now the spacecraft, which has been in hibernation mode with most of its electronics turned off, will begin work again -- this time searching for asteroids flying precariously close to Earth, as well as for asteroids that might be suitable for study.

"The WISE mission achieved its mission's goals...," said John Grunsfeld, NASA's associate administrator for science, in a statement. "NASA is now extending that record of success, which will enhance our ability to find potentially hazardous asteroids, and support the new asteroid initiative. Reactivating WISE is an excellent example of how we are leveraging existing capabilities across the agency to achieve our goal."

Asteroids have been a key point of interest for NASA. While scientists are always on the lookout for near-Earth objects that could impact the planet, NASA announced in April that President Obama's 2014 budget request included funding for a plan to capture and redirect an asteroid into orbit around Earth so astronauts could study it.

Ultimately, the project, which is getting resistance from House Republicans, is aimed at learning more about the makeup of asteroids in an attempt to protect the Earth from devastating collisions.

NASA said Wednesday that the WISE spacecraft will be revived next month and refocused on discovering and characterizing space rocks that can be found orbiting within 28 million miles of Earth.

NASA said scientists anticipate WISE will use its 16-inch telescope and infrared cameras to discover about 150 previously unknown near-Earth objects and characterize the size, ability to reflect light and thermal properties of about 2,000 others.

While WISE was working on its initial mission between 2010 and 2011, the spacecraft made about 7,500 images daily. It made the most accurate survey to date of near-Earth objects and discovered 21 comets, more than 34,000 asteroids in the main belt between Mars and Jupiter, and 135 near-Earth objects, NASA reported.

"The data collected two years ago have proven to be a gold mine...," said Lindley Johnson, NASA's WISE program executive. "It is important that we accumulate as much of this type of data as possible while the WISE spacecraft remains a viable asset.">>

mjimih wrote:

neufer wrote:

http://en.wikipedia.org/wiki/Kepler_%28spacecraft%29#Mission_status wrote: <<Possible future uses [for Kepler] ...Another proposal is to modify the software on Kepler to compensate. Instead of the stars being fixed and stable in Kepler's field of view, they will drift. However, software could track this drift and more or less completely recover the mission goals despite being unable to hold the stars in a fixed view.>>

seriously? that seems like a no brainer. any hangups for this solution foreseen?

Chris Peterson wrote:
I question the degree to which this could recover the mission goals. A drifting star image means that each pixel sees a shorter exposure time, which means less signal compared to the fixed readout noise. So the net effect is reduced S/N compared with a fixed star image. Not that this means Kepler couldn't still be used for its designed purpose, but I think it would be operating at a lower sensitivity.

Oh...the HORROR

• arXiv.org > astro-ph > arXiv:1309.0009 > 30 Aug 2013

orin stepanek wrote:Maybe 40 billion Earth sized planets!

mjimih wrote:Chris
Do you think my 50 million 'almost exactly like Earth is today' number, seems like a good guesstimate or not? maybe a billion?

The team is drafting plans for a new mission called K2, which would repurpose the space telescope in spite of its defects to continue the exoplanet hunt.

Since the problem is one of precision and stabilization, the plan is to point the telescope at the ecliptic, the plane drawn by Earth’s orbit. In this position, the pressure from solar radiation will act as a virtual third wheel, balancing out the remaining two reaction wheels to enable a pointing precision that (the team hopes) will be on par with what Kepler had in its full-functioning state. K2 would search for planets around smaller, cooler dwarf stars and in a range of stellar environments not in Kepler’s previous view, such as star clusters and nurseries. The team will submit their proposal in the next few months.