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Vision deterioration in astronauts likely owing to lack of a day-night cycle in intracranial pressure: Scientists

Vision deterioration in astronauts is likely owing to the lack of a day-night cycle in intracranial pressure, say scientists

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Mars plans to send a manned mission to mars by 2030, Pixabay
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New York, Jan 19, 2017: Vision deterioration in astronauts is likely owing to the lack of a day-night cycle in intracranial pressure, say scientists, adding that using a vacuum device to lower pressure for part of each day might prevent the problem.

To study how zero-gravity conditions affect intracranial pressure, researchers from University of Texas Southwestern Medical Centre recruited volunteer patients who had had a port permanently placed in their head as part of treatment for cancer.

The ports provided a way for researchers to measure intracranial pressure.

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NASA flights then flew the eight volunteers one by one on steep up-and-down maneuvers (parabolic flights) that created 20-second intervals of weightlessness.

The researchers measured intracranial pressure during the zero-gravity intervals and compared these with intracranial pressure during standard times of sitting, lying face upward (supine), and lying with head inclined downward.

The findings showed that intracranial pressure in zero-gravity conditions, such as exists in space, is higher than when people are standing or sitting on Earth, but lower than when people are sleeping on Earth.

“These challenging experiments were among the most ambitious human studies ever attempted and changed the way we think about the effect of gravity – and its absence – on pressure inside the brain,” said senior author Dr Benjamin Levine, Professor of Internal Medicine.

It suggests that the constancy of pressure on the back of the eye causes the vision problems astronauts experience over time.

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“The information from these studies is already leading to novel partnerships with companies to develop tools to simulate the upright posture in space while astronauts sleep, thereby normalising the circadian variability in intracranial pressure,” added Dr Levine.

“The idea is that the astronauts would wear negative pressure clothing or a negative pressure device while they sleep, creating lower intracranial pressure for part of each 24 hours,” noted first author Dr Justin Lawley in a paper appeared in the Journal of Physiology. (IANS)

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Chandra Observatory By NASA Back in Action

Scientists are currently performing analyses and tests to determine what options were available to recover the gyro to operational performance

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NASA's Chandra Observatory back in action. Pixabay

NASA Chandra X-Ray Observatory, observing the universe in high-energy light since 1999, is back in action after suffering a glitch due to the failure of the gyroscope and going into safe mode last week.

The cause of Chandra’s safe mode on October 10 has now been understood and the Operations team has successfully returned the spacecraft to its normal pointing mode, according to the US space agency.

“The safe mode was caused by a glitch in one of Chandra’s gyroscopes resulting in a 3-second period of bad data that, in turn, led the on-board computer to calculate an incorrect value for the spacecraft momentum. The erroneous momentum indication then triggered the safe mode,” NASA said in a statement late on Monday.

The team has completed plans to switch gyroscopes and place the gyroscope that experienced the glitch in reserve.

Once configured with a series of pre-tested flight software patches, the team will return Chandra to science operations which are expected to commence by the end of this week, NASA said.

On October 10, Chandra X-ray Observatory entered safe mode, in which the observatory is put into a safe configuration, critical hardware is swapped to back-up units, the spacecraft points so that the solar panels get maximum sunlight, and the mirrors point away from the Sun.

Chandra is 19 years old, which is well beyond the original design lifetime of five years. In 2001, NASA extended its lifetime to 10 years.

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NASA’s Dawn spacecraft, which has been orbiting the dwarf planet Ceres since March 2015, is also nearly out of fuel and might run out as early as October. Flickr

The US space agency said that it was also continuing to work towards resuming science operations of the Hubble Space Telescope that on October 5, entered safe mode after one of the three gyroscopes (gyros) being used to point and steady the telescope failed.

Gyroscopes help spacecraft maintain proper orientation.

Scientists are currently performing analyses and tests to determine what options were available to recover the gyro to operational performance.

Till that time, science operations with Hubble have been suspended.

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Besides Chandra and Hubble, NASA’s planet-hunting Kepler space telescope is also almost out of fuel. Kepler has found about 70 per cent of all known alien worlds to date.

NASA’s Dawn spacecraft, which has been orbiting the dwarf planet Ceres since March 2015, is also nearly out of fuel and might run out as early as October.

The space agency’s Mars rovers Opportunity and Curiosity too have faced issues of late. (IANS)