From Newsgroup: sci.space.news

http://www.nasa.gov/feature/ames/mission-manager-update-kepler-remains-stable-as-health-check-continues

April 15, 2016

Mission Manager Update: Kepler Remains Stable as Health Check Continues

The Kepler spacecraft remains stable as the process of returning it to
science continues. The cause of the anomaly, first reported on April 8, remains under investigation.

Since Sunday morning the spacecraft has remained safely "parked" in a
stable pointed configuration called Point Rest State. In this state, fuel usage remains low and the communication link to Earth is good. As of Tuesday, mission operations engineers had downlinked all the necessary data from
Kepler to triage the situation and plan the steps toward recovery.

The recovery to science began with a thorough assessment of the data,
which took a couple days, after which the team had learned all they could about the state of the spacecraft from the data. It was then time to turn
back on and test the components deemed low-risk to spacecraft health.
Testing begins on the Kepler spacecraft simulator at the flight planning center at Ball Aerospace in Boulder, Colorado. With the ground-based simulation

a success, we were ready to conduct the tests on Kepler, 75 million miles away. The engineers sent the instructions, along with commands for the spacecraft to protect itself and enter a safe operating mode if there
was a problem, and waited for the spacecraft to report back.

The spacecraft returned a response that is the equivalent of 'so far,
so good.' It did not experience any faults from switching on the components, and all the data suggest the components are working normally. The spacecraft is another step closer to returning to scientific observations for the
K2 mission.

The photometer - Kepler's camera - and the solid state recorder
are powered on. The subsystem interface box, which is the interface between the spacecraft sensors and the main computer, was only briefly powered
on for an initial assessment, but should be back online early next week.
The team will continue recovering the components, as they are deemed safe
and low-risk to the spacecraft.

Over the weekend, NASA's Deep Space Network (DSN) will remain in contact
with the spacecraft while the team gets some much-needed rest. To watch
the worldwide array of antennae communicate with the spacecraft, tune-in
to DSN Now.

The recovery started slowly and carefully, as we initially merely tried
to understand the situation and recover the systems least likely to have
been the cause. Over the last day and a half, we've begun to turn the
corner, by powering on more suspect components. With just one more to
go, I expect that we will soon be on the home stretch and picking up speed towards returning to normal science operations.

Updates will be provided as information warrants.

Regards,

Charlie Sobeck
Kepler and K2 mission manager
NASA's Ames Research Center

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