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Time-warp: Why June 30 will be a bit longer

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Washington: Strictly speaking, a day lasts 86,400 seconds. On June 30, the day will officially be a bit longer than usual because an extra second or “leap” second will be added and NASA has an explanation for this.

“The Earth’s rotation is gradually slowing down a bit, so leap seconds are a way to account for that,” said Daniel MacMillan, NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

This is the case according to the time standard that people use in their daily lives – Coordinated Universal Time or UTC.

UTC is “atomic time” — the duration of one second is based on extremely predictable electromagnetic transitions in atoms of cesium.

These transitions are so reliable that the cesium clock is accurate to one second in 1,400,000 years.

However, the mean solar day — the average length of a day, based on how long it takes the Earth to rotate — is about 86,400.002 seconds long.

“That is because the Earth’s rotation is gradually slowing down a bit owing to a kind of braking force caused by the gravitational tug of war between the Earth, the Moon and the Sun,” the US space agency said in a statement.

Scientists estimate that the mean solar day has not been 86,400 seconds long since the year 1820 or so.

This difference of two milliseconds, or two thousandths of a second — far less than the blink of an eye — hardly seems noticeable at first.

But if this small discrepancy were repeated every day for an entire year, it would add up to almost a second.

Typically, a leap second is inserted either on June 30 or December 31.

Normally, the clock would move from 23:59:59 to 00:00:00 the next day. But with the leap second on June 30, UTC will move from 23:59:59 to 23:59:60, and then to 00:00:00 on July 1.

In practice, many systems are instead turned off for one second.

Previous leap seconds have created challenges for some computer systems and generated some calls to abandon them altogether.

“In the short term, leap seconds are not as predictable as everyone would like,” said Chopo Ma, geophysicist at Goddard.

“The modelling of the Earth predicts that more and more leap seconds will be called for in the long-term but we cannot say that one will be needed every year,” Ma said.

From 1972, when leap seconds were first implemented, through 1999, leap seconds were added at a rate averaging close to one per year.

Since then, leap seconds have become less frequent.

This June’s leap second will be only the fourth to be added since 2000.

(IANS)

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NASA Running out of Fuel Required for Deep Space Missions : What will be the future of Exploration Missions?

The supply of the critical resource could be exhausted within the next decade, putting in jeopardy NASA's future missions that would require this fuel.

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What will happen to exploration missions if NASA runs out of fuel? Wikimedia

Washington, October 12, 2017 : The shortage of plutonium threatens NASA’s future mission to explore deep space, the US government has warned.

The break in production of plutonium 238 (Pu-238) between 1988 and 2015 could result in a bottleneck situation, where there is not enough of this scarce resource to power spacecraft during long-duration missions, Newsweek.com reported this week citing a government report.

NASA has long used radioisotope power systems (RPS) to generate reliable electrical power and heat energy for long-duration space missions, the US Government Accountability Office (GAO) report said.

But given NASA’s current plans for solar system exploration, the supply of this critical resource could be exhausted within the next decade, putting in jeopardy its future missions that would require this fuel, it warned.

RPS can operate where solar panels or batteries would be ineffective or impossible to use, such as in deep space or in shadowed craters, by converting heat from the natural radioactive decay of plutonium-238 (Pu-238) into electricity.

Missions such as Mars Curiousity rover and the Voyager 1 and 2 spacecraft use radioisotope thermoelectric generators as power source.

The production problems of Pu-238 and subsequent risks to NASA have been known for several years.

The Department of Energy (DOE) and its predecessor agencies have been providing Pu-238 and fabricating RPS for NASA and other federal agencies for more than five decades decades

ALSO READ NASA’S Mars Odyssey Spacecraft Captures First Images of the Martian Moon Phobos after 16 years

DOE currently maintains about 35 kgs of Pu-238 isotope designated for NASA missions, about half of which currently meets the power specifications for spaceflight.

However, given NASA’s current plans for solar system exploration, this supply could be exhausted within the next 10 years.

Specifically, NASA plans to use about 3.5 kg of Pu-238 isotope for one RPS to power the Mars 2020 mission, the Government Accountability Office report said.

NASA may also use an additional 10.5 kg of Pu-238 isotope for its New Frontiers #4
mission if three RPS are used.

If DOE’s existing Pu-238 supply is used for these two missions, NASA would be forced to eliminate or delay future missions requiring RPS until DOE produces or acquires more Pu-238, the report said. (IANS)

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NASA’S Mars Odyssey Spacecraft Captures First Images of the Martian Moon Phobos after 16 years

Phobos has an oblong shape with an average diameter of about 22 kilometres

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On September 29, Phobos was observed by Thermal Emission Imaging System (THEMIS) camera on Mars Odyssey orbiter, which has been launched in 2001. Pixabay

Washington, October 8, 2017 : After orbiting the Red Planet for 16 years, NASA’s Mars Odyssey spacecraft has captured its first images of the Martian moon Phobos.

The Thermal Emission Imaging System (THEMIS) camera on Mars Odyssey orbiter, launched in 2001, observed Phobos on September 29.

Phobos has an oblong shape with an average diameter of about 22 kilometres.

Cameras on other Mars orbiters have previously taken higher-resolution images of Phobos, but none with the infrared information available from THEMIS.

Observations in multiple bands of thermal-infrared wavelengths can yield information about the mineral composition of the surface, as well as the surface texture, NASA said in a statement this week.

“Although THEMIS has been at Mars for 16 years, this was the first time we have been able to turn the spacecraft around to look at Phobos,” said THEMIS Mission Planner Jonathon Hill of Arizona State University.

The researchers combined visible-wavelength and infrared data to produce an image color-coded for surface temperatures of this moon, which has been considered for a potential future human-mission outpost, NASA said.

“This half-moon view of Phobos was chosen because it allowed us to observe a wide range of temperatures on the surface,” Hill added.

ALSO READ NASA Scientists Reveal New Information on Mars’ Formation and Evolution, Claim The Red Planet has a Porous Crust

One major question about Phobos and Mars’ even smaller moon, Deimos, is whether they are captured asteroids or bits of Mars knocked into the sky by impact.

The researchers believe that compositional information from THEMIS might help pin down their origin.

Since Odyssey began orbiting the Red Planet in 2001, THEMIS has provided compositional and thermal properties information from all over Mars, but never before imaged either Martian moon.

The September 29 observation was completed to validate that the spacecraft could safely do so, as the start of a possible series of observations of Phobos and Deimos in coming months.

“There is heightened interest in Phobos because of the possibility that future astronauts could perhaps use it as an outpost,” said Odyssey Project Scientist Jeffrey Plaut of NASA’s Jet Propulsion Laboratory in Pasadena, California. (IANS)

 

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NASA to put humans on the Moon again: Mike Pence

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NASA to put humans on the Moon again: Mike Pence (Image:Wikimedia)

Washington, Oct 6: The Trump administration will direct NASA to land humans on the Moon and establish presence on the lunar surface before sending astronauts to the Red Planet and beyond, US Vice President Mike Pence has said.

Pence made the administration’s intentions known in a Wall Street Journal op-ed, as well as a speech he gave during the inaugural meeting of the National Space Council — a newly resurrected executive group aimed at guiding the US space agenda, The Verge reported on Thursday.

“We will return NASA astronauts to the Moon — not only to leave behind footprints and flags, but to build the foundation, we need to send Americans to Mars and beyond,” he told reporters at the Smithsonian National Air and Space Museum’s Steven F. Udvar-Hazy Center in Chantilly, Virginia.

Pence made it clear that space is a national priority, acting NASA Administrator Robert Lightfoot said in a statement after the first meeting of the Council.

“The vice president also announced a call for renewed U.S. leadership in space – with a recommendation to the president that NASA help lead and shape the way forward,” Lightfoot said.

“Specifically, NASA has been directed to develop a plan for an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system, returning humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations,” Lightfoot added.

The Council acknowledged the strategic importance of cis-lunar space — the region around the Moon — which will serve as a proving ground for missions to Mars and beyond, Lightfoot added. (IANS)