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2018-03-21 17:41:10 UTC
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Has anybody written any sci-fi about refueling Kepler?Raw Message
And giving it repairs and a tune-up while they are there?
(good pictures at both sites cited below.)
NASA's Prolific Planet-Hunting Kepler Spacecraft is running out of fuel
NASA's Prolific Planet-Hunting Kepler Spacecraft Is Running Out of Fuel
By Elizabeth Howell, Space.com Contributor | March 16, 2018 03:00pm ET
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NASA's Prolific Planet-Hunting Kepler Spacecraft Is Running Out of Fuel
A view of Kepler, whose extended mission may be nearing an end as it
runs out of fuel.
Credit: NASA
The Kepler space telescope's prolific planet-hunting days will end soon.
After finding more than 2,300 confirmed planets across its two missions,
Kepler is low on fuel and will run out within several months, according
to NASA engineers.
"Our current estimates are that Kepler's tank will run dry within
several months — but we've been surprised by its performance before! So,
while we anticipate flight operations ending soon, we are prepared to
continue as long as the fuel allows," Charlie Sobeck, system engineer
for the Kepler mission, said in a NASA statement.
"The Kepler team is planning to collect as much science data as possible
in its remaining time and beam it back to Earth before the loss of the
fuel-powered thrusters means that we can't aim the spacecraft for data
transfer," he added. "We even have plans to take some final calibration
data with the last bit of fuel, if the opportunity presents itself."
[Kepler's 7 Greatest Exoplanet Discoveries (So Far)]
The Kepler data will also be plumbed for years as scientists seek to
confirm other possible planets in its archive. As of today (March 16),
Kepler has confirmed the existence of 2,342 planets across its two
missions — about two-thirds of all exoplanets ever discovered. (Just
last month, Kepler scientists released a batch of 95 planets that are
included in this total.) On top of that, there are 2,245 possible
planets that require more observation — a ripe ground for future follow-up.
The $600 million Kepler mission launched in 2009 to search for
exoplanets in a fixed location in the constellation Cygnus. For four
years, it watched the stars for the telltale dimming that occurs when an
exoplanet crosses the face of a star. The mission's ultimate aim was to
find rocky exoplanets that were Earth-size or smaller — a type of planet
rarely found when Kepler went into orbit. But within a few years,
Kepler's data showed that rocky planets are extremely common in the
universe.
Infographic showing how the K2 mission works.
Infographic showing how the K2 mission works.
Credit: NASA
The mission was originally slated to last two years, but it was
extended. In 2013, after four years of operation, three of Kepler's four
gyroscopes — the "wheels" that aimed the craft — failed. Kepler couldn't
maintain a steady gaze in space anymore. So NASA devised a new mission
for the spacecraft, called K2.
Using the pressure of the solar wind to maintain position, the
spacecraft would rotate between different areas of the sky every three
months (which, in the parlance of the mission, is called a "campaign").
This would allow Kepler to keep looking for exoplanets, albeit with a
shorter orbital period. Even with K2, Kepler exceeded expectations.
"Initially, the Kepler team estimated that the K2 mission could conduct
10 campaigns with the remaining fuel," Sobeck said. "It turns out, we
were overly conservative. The mission has already completed 16
campaigns, and this month entered its 17th."
He added that there is no gas gauge on Kepler showing when it might run
out of fuel, so the team relies on estimates. These estimates consider
factors such as changes in thruster performance and drops in the fuel
tank's pressure. But Kepler has an advantage: It's located in deep
space. It's not close to a planet hosting icy moons, unlike the Galileo
mission near Jupiter (which orbited there between 1995 and 2003) and the
Cassini mission near Saturn (which orbited the planet from 2004 to 2017) .
When Cassini and Galileo ran low on fuel, NASA engineers deliberately
aimed these spacecraft on death dives into their respective planets,
just in case the drifting machines accidentally smacked into an icy moon
that has the potential to host life. Kepler, by contrast, can keep going
as long as feasible.
"We can afford to squeeze every last drop of data from the spacecraft —
and ultimately that means bringing home even more data for science,"
Sobeck said. "Who knows what surprises about our universe will be in
that final downlink to Earth?"
While Kepler is in the twilight of its mission, another planet-hunting
spacecraft is ready to take the stage. NASA's Transiting Exoplanet
Survey Satellite will launch no earlier than April 16 from Cape
Canaveral Air Force Station in Florida. It will do a full-sky survey of
at least 200,000 stars, focusing on planets orbiting stars that are
brighter and closer to Kepler. This means it will be easier for
scientists do follow-up observations using ground telescopes or the
James Webb Space Telescope that is slated to launch in 2019.
Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.
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https://www.space.com/40008-kepler-planet-hunter-running-out-of-fuel.html
oh, by the way, from
https://www.airspacemag.com/daily-planet/keplers-unusual-orbit-54411507/
"Unlike the Hubble Space Telescope, which orbits Earth, Kepler has been
placed in what’s called an “Earth trailing” orbit around the sun. A
little wider and slower than our own orbit, the spacecraft will take 371
days to complete one circuit. Each day Kepler falls a little farther
behind Earth—eventually the gap will open to tens of millions of miles.
This unusual orbit, designed by Johnny Kwok of the Jet Propulsion
Laboratory and used for the first time with the Spitzer infrared space
telescope launched in 2003, has advantages for astronomical telescopes.
One is that Earth doesn’t block their view of the sky. The spacecraft
doesn’t need periodic boosts to maintain its altitude above Earth. And
best of all, it’s a very fuel-efficient orbit, requiring less energy
(smaller rocket, lower cost) to reach than the L2 Lagrange point that
originally was to have been Kepler’s destination.
Read more at
https://www.airspacemag.com/daily-planet/keplers-unusual-orbit-54411507/#JvWMsKwRXFGelud7.99