NEARCHUS: NASA Image of the Day, Aug 12th..[ 1628 ]

The Hellenic Navy (HN) (Greek: Πολεμικό Ναυτικό, Polemikó Naftikó, abbreviated ΠΝ) is the naval force of Greece, part of the Greek Armed Forces. The modern Greek navy has its roots in the naval forces of various Aegean Islands, which fought in the Greek War of Independence. During the periods of monarchy (1833–1924 and 1936–1973) it was known as the Royal Navy (Βασιλικόν Ναυτικόν, Vasilikón Naftikón, abbreviated ΒΝ).The total displacement of all the navy's vessels is approximately 150,000 tons.The motto of the Hellenic Navy is "Μέγα το της Θαλάσσης Κράτος" from Thucydides' account of Pericles' oration on the eve of the Peloponnesian War. This has been roughly translated as "Great is the country that controls the sea". The Hellenic Navy's emblem consists of an anchor in front of a crossed Christian cross and trident, with the cross symbolizing Greek Orthodoxy, and the trident symbolizing Poseidon, the god of the sea in Greek mythology. Pericles' words are written across the top of the emblem. "The navy, as it represents a necessary weapon for Greece, should only be created for war and aim to victory."...............The Hellenic Merchant Marine refers to the Merchant Marine of Greece, engaged in commerce and transportation of goods and services universally. It consists of the merchant vessels owned by Greek civilians, flying either the Greek flag or a flag of convenience. Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and a key element of Greek economic activity since the ancient times. Nowadays, Greece has the largest merchant fleet in the world, which is the second largest contributor to the national economy after tourism and forms the backbone of world shipping. The Greek fleet flies a variety of flags, however some Greek shipowners gradually return to Greece following the changes to the legislative framework governing their operations and the improvement of infrastructure.

Blogger Tips and Tricks

This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς....This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς.........

Friday, August 13, 2010

NASA Image of the Day, Aug 12th..[ 1628 ]

The latest NASA "Image of the Day" image.

50 Years of Communications in Space

The idea behind a communications satellite is simple: send a signal into space, and send it back down to another spot on the globe. In NASA's early days, engineers discovered the easiest way to accomplish this: bounce signals off a giant metal balloon floating in orbit.

The concept was developed into the aptly-named Echo program, and Echo 1A became the first successful launch of the project on Aug. 12, 1960. Echo 1A, now commonly known as just Echo I, was a 100 foot diameter balloon made of mylar polyester.

The spacecraft was designed as a passive communications reflector for transcontinental and intercontinental telephone, radio, and television signals.

Pictured here is a scale prototype of the Echo satellite undergoing a Skin Stress Test on May 1, 1960.

The prototype was 12 feet in diameter, with the size being chosen because that was the ceiling height in the NASA Langley model shop. After an unsuccessful launch attempt for the original Echo I satellite, Echo 1A and the follow-on Echo II were successfully launched. The Echo projects were instrumental in letting the world see that the U.S. was a major force in the space race not very far behind Russia.

Among the many contributions of the Echo programs are the first voice communication via satellite which was made by none other than then President Eisenhower and the first coast-to-coast telephone call using a satellite. In addition, the Echo programs resulted in advances in atmospheric density, solar pressure, gossamer structures, solar sailing, and transmitting videos via satellites.

The Echo 1A satellite re-entered the atmosphere on May 24, 1968.

Image Credit: NASA
Πέμπτη, 12 Αύγουστος

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