Friday, August 1, 2014

Astronomical Calendar: 2014 August


Image of one of the first practical photographic cameras. This Daguerreotype camera was built by La Maison Susse Frères in 1839, with a lens by Charles Chevalier. August 19 marks the 175th anniversary of the release of the first practical photographic process patent.
More information: http://www.worldphotoday.org/  (Image Source: Wikipedia.org )

Astronomical Calendar for 2014 August:

Link >>> http://buhlplanetarium4.tripod.com/astrocalendar/2014.html#aug


The current month's Astronomical Calendar can also be found on the cover page of the History of The Buhl Planetarium and Institute of Popular Science, Pittsburgh web site at this link:

Link >>> http://buhlplanetarium.tripod.com/#astrocal


Source: Friends of the Zeiss.

2014: 75th Year of Pittsburgh's Buhl Planetarium Historic Zeiss II Planetarium Projector at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.


Want to receive SpaceWatchtower blog posts in your inbox ?
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gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
  < http://andrewcarnegie2.tripod.com/transit >

Wednesday, July 30, 2014

NASA Spacecraft Prepare for Close Comet Flyby of Mars

This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers). The comet's trail of dust particles shed by the nucleus might be wide enough to reach Mars or might also miss it. For more information about this comet, see http://mars.nasa.gov/comets/sidingspring/.
This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers).
Image Credit: NASA/JPL-Caltech

NASA is taking steps to protect its Mars orbiters, while preserving opportunities to gather valuable scientific data, as Comet C/2013 A1 Siding Spring heads toward a close flyby of Mars on Oct. 19.

The comet’s nucleus will miss Mars by about 82,000 miles (132,000 kilometers), shedding material hurtling at about 35 miles (56 kilometers) per second, relative to Mars and Mars-orbiting spacecraft. At that velocity, even the smallest particle -- estimated to be about one-fiftieth of an inch (half a millimeter) across -- could cause significant damage to a spacecraft.

NASA currently operates two Mars orbiters, with a third on its way and expected to arrive in Martian orbit just a month before the comet flyby. Teams operating the orbiters plan to have all spacecraft positioned on the opposite side of the Red Planet when the comet is most likely to pass by.

"Three expert teams have modeled this comet for NASA and provided forecasts for its flyby of Mars," explained Rich Zurek, chief scientist for the Mars Exploration Program at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "The hazard is not an impact of the comet nucleus, but the trail of debris coming from it. Using constraints provided by Earth-based observations, the modeling results indicate that the hazard is not as great as first anticipated. Mars will be right at the edge of the debris cloud, so it might encounter some of the particles -- or it might not."

More - Link >>> http://www.nasa.gov/press/2014/july/nasa-s-mars-spacecraft-maneuvers-to-prepare-for-close-comet-flyby/#.U9gGTaKweKI

Source: NASA.

2014: 75th Year of Pittsburgh's Buhl Planetarium Historic Zeiss II Planetarium Projector at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.


Want to receive SpaceWatchtower blog posts in your inbox ?
Send request to < spacewatchtower@planetarium.cc >..

gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
  < http://andrewcarnegie2.tripod.com/transit >

Saturday, July 26, 2014

Moon Set Favors July Meteor Shower; Also Web-Casts



By Glenn A. Walsh
Reporting for SpaceWatchtower

While the Perseid Meteor Shower, next month, is considered the best meteor shower of the year, this month's Southern Delta Aquariid Meteor Shower may actually be easier to see, due to the Moon setting early during this meteor shower's peak.

The Southern Delta Aquariid Meteor Shower, generally visible from mid-July to mid-August and particularly over the next week, peaks at 5:00 a.m. EDT / 9:00 Coordinated Universal Time on Tuesday Morning, 2014 July 29. New Moon occurs tonight, Saturday, 2014 July 26 at 6:42 p.m. EDT / 22:42 UTC. So, following New Moon, the Moon begins the waxing crescent phase, but sets in the early to mid-evening over the next week.

At its peak, if you have ideal observing conditions, you may be able to see about 20 meteors an hour during the Southern Delta Aquariid Meteor Shower.

However, to see these meteors you need to be away from city lights, as artificial lighting can often drown-out the dimmer meteors. The best time to see any meteor shower is between local midnight and morning twilight, when the Earth is actually turning-into the meteor shower.

Binoculars and telescopes are not very useful for finding meteors. Meteors streak across the sky in a very short period of time, too short to aim binoculars or a telescope. So, the best way to view a meteor shower is lie on the ground, in an area with a good view of the entire sky (with few obstructions such as buildings, trees or hills), and keep scanning the entire sky.

Meteor showers appear to emanate from a radiant point in the sky. For the Southern Delta Aquariid Meteor Shower, the radiant appears to be the Star Delta Aquarii, the brightest star in the Constellation Aquarius. However, you should not, necessarily be looking only at Aquarius, when looking for meteors in this shower. Meteors can appear in any part of the sky at any time.

Southern Hemisphere observers are a little favored during this meteor shower, as the radiant is higher in the sky south of the equator, during the peak of this meteor shower.

Of course, meteor showers. like all celestial observations, are weather-permitting. If the weather in your area does not permit direct viewing outdoors of this meteor shower, it can viewed during special web-casts at a couple sites on the Internet.

Internet Sites to View Southern Delta Aquariid Meteor Shower Near Peak, July 28 to 30:

Slooh Community Observatory: Link >>> http://live.slooh.com/

NASA Marshall Spaceflight Center: Link >>> http://www.nasa.gov/watchtheskies/delta-aquarids-ustream-2014.html#.U9QAq6KweKI

More on the Southern Delta Aquariid Meteor Shower:
Link >>> http://en.wikipedia.org/wiki/Southern_Delta_Aquarids

Source: Glenn A. Walsh, Reporting for SpaceWatchtower, a project of Friends of the Zeiss.


2014: 75th Year of Pittsburgh's Buhl Planetarium Historic Zeiss II Planetarium Projector at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.


Want to receive SpaceWatchtower blog posts in your inbox ?
Send request to < spacewatchtower@planetarium.cc >..

gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
  < http://andrewcarnegie2.tripod.com/transit >

Thursday, July 24, 2014

Earth Misses Catastrophe of 2012 Solar Storm

If an asteroid big enough to knock modern civilization back to the 18th century appeared out of deep space and buzzed the Earth-Moon system, the near-miss would be instant worldwide headline news.

Two years ago, Earth experienced a close shave just as perilous, but most newspapers didn't mention it. The "impactor" was an extreme solar storm, the most powerful in as much as 150+ years.

"If it had hit, we would still be picking up the pieces," says Daniel Baker of the University of Colorado.

splash
A ScienceCast video recounts the near-miss of a solar superstorm in July 2012.  Play it

Baker, along with colleagues from NASA and other universities, published a seminal study of the storm in the December 2013 issue of the journal Space Weather.  Their paper, entitled "A major solar eruptive event in July 2012," describes how a powerful coronal mass ejection (CME) tore through Earth orbit on July 23, 2012.  Fortunately Earth wasn't there.  Instead, the storm cloud hit the STEREO-A spacecraft.

"I have come away from our recent studies more convinced than ever that Earth and its inhabitants were incredibly fortunate that the 2012 eruption happened when it did," says Baker.  "If the eruption had occurred only one week earlier, Earth would have been in the line of fire.

More - Link >>> http://science.nasa.gov/science-news/science-at-nasa/2014/23jul_superstorm/

Source: NASA Science News.

2014: 75th Year of Pittsburgh's Buhl Planetarium Historic Zeiss II Planetarium Projector at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.


Want to receive SpaceWatchtower blog posts in your inbox ?
Send request to < spacewatchtower@planetarium.cc >..

gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
  < http://andrewcarnegie2.tripod.com/transit >

Tuesday, July 22, 2014

European Space Probe Aims for 1 Comet, Finds 2

(Image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)

by Jacob Aron

Comet-chaser Rosetta has lucked out with a two-for-one deal. Pictures from the European Space Agency (ESA) probe suggest that its target comet, Churyumov-Gerasimenko, is actually two icy rocks stuck together in an arrangement known as a contact binary.

"This is the reason we organise these missions, to find surprises," says Pedro Lacerda of the Max Planck Institute for Solar System Research in Göttingen, Germany, who has set up a team to analyse results from Rosetta.

Launched 10 years ago, Rosetta's mission is to make the first-ever landing on a comet. This latest discovery could complicate the mission.

It's not yet clear whether these are two different comets that have come together, or parts of a single comet that fractured but remained gravitationally bound.

More - Link >>> http://www.newscientist.com/article/dn25904-rosettas-target-comet-is-a-surprise-double-space-rock.html#.U87rvaKweKI

Source: New Scientist Magazine.

2014: 75th Year of Pittsburgh's Buhl Planetarium Historic Zeiss II Planetarium Projector at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.


Want to receive SpaceWatchtower blog posts in your inbox ?
Send request to < spacewatchtower@planetarium.cc >..

gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
  < http://andrewcarnegie2.tripod.com/transit >

Sunday, July 20, 2014

45 Years Ago: Man Lands on the Moon !

http://www.nasa.gov/sites/default/files/62297main_neil_on_moon_full.jpg
The American Flag mounted at Tranquility Base on the Moon, after the landing of Apollo 11.
(Image Source: NASA)

By Glenn A. Walsh
Reporting for SpaceWatchtower

At the moment of this blog post, 45 years ago, man first landed on another planetary body, the Earth's Moon. On Sunday Afternoon, 1969 July 20 at 4:17:40 p.m. EDT / 20:17:40 Coordinated Universal Time, the Lunar Excursion Module (LEM) named "Eagle," which included American Astronauts Neal Armstrong and Buzz Aldrin, landed in the Moon's Sea of Tranquility, with only 25 seconds of fuel left.

Upon landing, Neal Armstrong announced, "Houston, Tranquility Base here. The Eagle has landed." Charles Duke, the CAPCOM (Capsule Communicator in the Johnson Space Flight Center in Houston). replied, "Roger, Twan— Tranquility, we copy you on the ground. You got a bunch of guys about to turn blue. We're breathing again. Thanks a lot."

The mission schedule called for the lunar astronauts to have a five hour sleep period, before preparing for walking on the Moon, due to the hectic schedule they had followed for landing the LEM on the Moon. However, both astronauts chose to forgo the sleep period, as they felt they probably could not get to sleep anyway.

Originally, the first walks on the Moon, by the two astronauts, had been scheduled for the early morning hours, North American time, of Monday ("Moonday" - the day of the week actually named for the Moon), July 21. However, with the elimination of the early sleep period, the astronauts started immediately to prepare for stepping onto the lunar surface. This eventually allowed the first steps on the Moon to be seen on live television throughout the world, at the end of the Sunday evening prime-time television period in the Eastern Time Zone of North America (and even earlier for the rest of the United States), instead of during the middle-of-the-night in North America as was originally scheduled.

Neal Armstrong first opened the door of the LEM late Sunday Evening, 1969 July 20 at 10:39 p.m. EDT / July 21, 2:39 UTC. He set foot on  the Moon at precisely 10:56:20 p.m. EDT / July 21, 2:56:20 UTC (hence, by the time scale used by most scientists, Coordinated Universal Time, the first step on the Moon did occur on "Moonday"), saying the now historic words, "That's one small step for [a] man, one giant leap for mankind."

There is some debate (as described in news articles listed below in "Related Blog Posts") as to whether Neal Armstrong's now famous quote said "one small step for man" or "one small step for a man." However, there was no doubt in the minds of millions of television viewers on Earth (the television audience for this event has been estimated to be at least 600 million, worldwide) that two Americans had walked on the Moon.

On 1969 July 20, the Moon was a waxing crescent phase, with 31 percent of the Moon's visible disk illuminated. The lunar phase of First Quarter did not occur until July 22 at 8:10 a.m. EDT / 12:10 UTC. Of course, the Sea of Tranquility, where the Apollo 11 LEM landed, was within this 31 percent of the illuminated Moon, as viewed from Earth.

That day in Pittsburgh, the Moon rose at 11:57 a.m. EDT / 15:57 UTC and set at 11:44 p.m. EDT / July 21, 3:44 UTC. So, at the time of the first steps of men on the Moon, the Moon was still visible in the sky in Pittsburgh, and in most of North America, weather-permitting.

More on the historic mission of Apollo 11:
Link 1 >>> http://www.nasa.gov/externalflash/apollo40/
Link 2 >>> http://www.nasa.gov/apollo45/
Link 3 >>> http://en.wikipedia.org/wiki/Apollo_11

NASA commemorates the historic flight of Apollo 11:
Link >>> http://www.jpl.nasa.gov/news/news.php?release=2014-229&utm_source=iContact&utm_medium=email&utm_campaign=NASAJPL&utm_content=daily20140715

Photograph of Astronaut Neal Armstrong about to step on the Moon for the first time, from the live television broadcast:
Link >>> http://spacewatchtower.blogspot.com/2014/07/astronomical-calendar-2014-july.html

The Historic Mission of Apollo 11, Man Walks on the Moon for the First Time
A Personal Remembrance From 40 Years Ago By Glenn A. Walsh (2009 July):
Link >>> http://buhlplanetarium2.tripod.com/bio/Apolloremembrance.htm

Related Blog Posts ---

45th Anniversary: Apollo 8 Orbits the Moon Christmas Eve  (2013 Dec. 24):

Link >>> http://spacewatchtower.blogspot.com/2013/12/45th-anniversary-apollo-8-orbits-moon.html

 

JFK: Loss of the Man Who Sent Us to the Moon  (2013 Nov. 22):

Link >>> http://spacewatchtower.blogspot.com/2013/11/jfk-loss-of-man-who-sent-us-to-moon.html

 

Moon Day - A National Holiday ?  (2013 July 20):

Link >>> http://spacewatchtower.blogspot.com/2013/07/moon-day-national-holiday.html

 

Famous Moon Landing Quote Scrutinized by Scientists  (2013 June 2):

Link >>> http://spacewatchtower.blogspot.com/2013/06/famous-moon-landing-quote-scrutinized.html

 

Neil Armstrong's First Words on Moon: Brother Claims Scripted  (2013 Jan. 3):

Link >>> http://spacewatchtower.blogspot.com/2013/01/neil-armstrongs-first-words-on-moon.html

 

1st Man on Moon Dies at 82  (2012 Aug. 25):
Link >>> http://spacewatchtower.blogspot.com/2012/08/1st-man-on-moon-dies-at-82.html

 

Most U.S. Flags on Moon Still Standing  (2012 July 28):

Link >>> http://spacewatchtower.blogspot.com/2012/07/most-us-flags-on-moon-still-standing.html

 

Source: Glenn A. Walsh, Reporting for SpaceWatchtower, a project of Friends of the Zeiss.


2014: 75th Year of Pittsburgh's Buhl Planetarium Historic Zeiss II Planetarium Projector at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.


Want to receive SpaceWatchtower blog posts in your inbox ?
Send request to < spacewatchtower@planetarium.cc >..

gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
  < http://andrewcarnegie2.tripod.com/transit >

Thursday, July 17, 2014

Solar Sail Spacecraft Test in 2016








LightSail is designed to be the first mission
to demonstrate controlled solar sailing for
small, affordable spacecraft called cubesats.
Josh Spradling / The Planetary Society
LightSail 1 will launch onboard SpaceX’s Falcon Heavy rocket to demonstrate propellant-free propulsion.

By Clara Moskowitz

Just as sailboats use wind pressure to propel through water, solar sails use the pressure from light radiated by the sun to move through space. Once the province of science fiction authors such as Arthur C. Clarke, solar sailing is gradually moving into the realm of reality. A privately funded $4.5-million mission to test solar sailing technology called LightSail now has a launch date in April 2016 and a ride to space onboard SpaceX’s Falcon Heavy rocket. Once in orbit, LightSail 1 will make maneuvers using sunlight, rather than rocket fuel. “Solar sailing has been under development at a slow pace for a lot of years,” says LightSail Project Manager Doug Stetson of the nonprofit Planetary Society, which is organizing and funding the mission. “The reason it’s hung on all these years is because of the potential for basically free propulsion throughout the solar system.”

LightSail 1 is a small spacecraft made of a stock of three 10-centimeter-wide squares called cubesats. After being carried to medium Earth orbit—more than 2,000 kilometers above the planet, high enough to escape most of its atmospheric drag—LightSail 1 will deploy four ultrathin Mylar sails that will stretch to 32 square meters (potentially large enough for naked-eye observers to spot from the ground). These sails will be bombarded with sunlight and each light particle, or photon, that impacts them will impart a tiny bit of momentum. Added up, those tiny bits should be enough to move the spacecraft without the need for heavy and expensive chemical propellant. If LightSail’s orbital speed increases once it deploys its sail, engineers will know it works.

In theory, solar sailing should be powerful enough to propel a spacecraft out of Earth orbit and into the solar system. “The disadvantage to that is it takes a long time [to move], just like it takes a lot longer to sail to the Bahamas than drive a speedboat,” Stetson says. Still, in space beyond Earth’s atmosphere without friction to stop it, once a solar sail gets going, it keeps accelerating as long as sunlight keeps hitting it. That makes solar sails an appealing option to explore the whole of the solar system and beyond. Many experts say they’re the likeliest candidate to propel the first interstellar mission to another star, with extra thrust supplied by a laser, perhaps stationed in orbit around the sun, aimed at the sail in addition to sunlight. One downside, however, is that solar sails don’t come with brakes or any means of changing trajectory or slowing down once they’re zooming. One possible solution is using a planet or star’s gravity to decelerate the craft or slingshot it along a desired path.

More - Link >>> http://www.scientificamerican.com/article/lightsail-solar-sailing-launch-date/?&WT.mc_id=SA_DD_20140716

Source: Scientific American Magazine.

2014: 75th Year of Pittsburgh's Buhl Planetarium Historic Zeiss II Planetarium Projector at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.


Want to receive SpaceWatchtower blog posts in your inbox ?
Send request to < spacewatchtower@planetarium.cc >..

gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
  < http://andrewcarnegie2.tripod.com/transit >