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posted Feb 7, 2015, 8:39 PM by Ranmini Perera   [ updated Jul 14, 2016, 1:51 PM by Upali Salpadoru ]

Hubble Space Telescope.

Fig. 1.A photograph of the planet Saturn taken by HST.

On the 24th of April NASA celebrated the 25th Anniversary of the launching of the Hubble Space Telescope. into orbit. 

It was a massive object, the size of a bus, of 11,110 kg positioned in an orbit around the earth at a height of over 500 km.      

It was doing the trip round the Earth in 95 minutes. The main mirror was 2.4 m. and weighed 828 kg.

Just after launching several problems cropped up. The space photos were no better than those taken from the Land Telescopes. 

In the final grounding of the main mirror, there had been a defect of 2 micrometres.   

The media screamed, “The billion dollar blunder of NASA”.

NASA was silent; they knew what they were doing. 

They had built a masterpiece whose instruments could be replaced or repaired in space. Although the fault remained as it was the light from stars collected by the mirror was made to reflect perfectly using a special device. Most of the highly sophisticated instruments have been replaced periodically. 

Now the eyes of the Telescope are geared to the edge of the universe which is 14 billion light years away.

The sensitivity is such that it cannot be directly aimed at the moon as it is too bright. In addition to normal light it can use rays in the Ultra Violet and Infrared regions. 

HST has made several discoveries which are extremely valuable. Among a few others, it produced sufficient evidence to show that the galaxies are flying at an accelerated speed. It also confirmed the theory of dark matter.

NASA will probably use it for about another five years and will be brought down to Earth as it is too big to be burnt in entering our atmosphere.

 

Voyager Probe.

Has the Voyager entered No man’s land –Inter stellar Space ?  
Well the scientists are not sure.  It is being bathed not with the solar emanations but by  a shower of cosmic dust. On 225-8-2012 scientist believed that V-1 has left the influence of the solar system but now they find that, it has still not escaped the magnetic field of the sun.
We are sharing a Reuters report published by The Dominion Post New Zealand.

Fig 2.  Voyager,launched for 5 yrs; now 35 yrs old.

 

  • A total of 11,000 work-years was devoted to the Voyager project through the Neptune encounter.

The arrangement of Jupiter, Saturn, Uranus and Neptune at the time of launch,  allowed the V-1 qnd V-2  to swing from one planet to the next with the minimum of fuel. “The flyby of each planet bends the spacecraft's flight path and increases its velocity enough to deliver it to the next destination”

 

  • In search of intelligent beings there is a gold plated audio disc with messages in fifty five languages and various earthly sounds.
 

Fig.3. Paths of the Space probes.

 

  • Jupiter's Moons:

 

Flying past Amalthea, Io, Europa, Ganymede and Callisto on 5 March, V-1 returned spectacular photos of their terrain,.It found five new moons and a ring system consisting of thousands of bands, discovered a new ring  G, and found  satellites that keep the rings well defined. During its flyby, the it photographed Saturn's moons Titan, Mimas, Enceladus, Tethys, Dione, and Rhea. Plenty of ice has been detected.V- 1 passed Titan which had a thick atmosphere that completely hid the surface which was composed on 90 % nitrogen. The Pressure and temperature at the surface was 1.6 A, and -180° C, respectively.

 

 

Voyager 1

Voyager 2

Launch

5-9-1977

20-8-1977

 

First photo of Earth and Moon

 

5-3-79

Closest approach to Jupiter

 

9-7-79

 

Closest approach to Jupiter

 

Flies by Saturn

 

12-11-80

Trip out of the Solar System

 

25-8-81

 

Flies by Saturn

 

1982

 

First-ever encounter with Uranus

1987

 

Voyager 2 "observes" Supernova 1987A

1988

 

First colour images of Neptune

1989

 

Voyager 2 returns first color images of Neptune

17-2-1998

Passes Pioneer 10 to become the most distant human-made object in space

 

 

2004 Dec. 15

 
   

Voyager 1 crosses Termination Shock

 

2007 Sep. 5

 

Voyager 2 crosses Termination Shock

 








 We are sharing a Reuters report published by The Dominion Post New Zealand.

Reports last summer that Nasa's long-lived Voyager 1 space probe had finally left the solar system turned out to be a bit premature, scientists said on Thursday.
Rather, the spacecraft, which was launched in 1977 for a five-year mission to study Jupiter and Saturn, has found itself in a previously unknown region between the outermost part of the solar system and interstellar space.
It is an unusual and unexpected thoroughfare, a place where charged particles from the sun have virtually disappeared and those coming from galactic cosmic rays beyond the solar system are plentiful.
By that measure alone, scientists initially thought Voyager 1 did indeed finally reach interstellar space on Aug. 25, 2012, becoming the first man-made object to leave the solar system.
But one key measurement killed that theory. The magnetic field in which Voyager 1 travelled was still aligned like the sun's. If the probe were truly in interstellar space, scientists expect that the direction of the magnetic field would be different.
"You can never exclude a really peculiar coincidence, but this was very strong evidence that we're still in the heliosheath" - the bubble of plasma from the sun that surrounds the solar system, said Voyager scientist Leonard Burlaga, with NASA's Goddard Space Fight Centre in Greenbelt, Maryland.
Additional measurements later turned up a second odd reading. The cosmic ray particles were not uniformly distributed around Voyager 1 like scientists expected them to be in interstellar space. Instead, the charged particles, which stem from distant supernova explosions, were oriented in particular directions.
That led scientists to conclude that Voyager 1 was in some sort of magnetic boundary zone, where particles from inside and outside the solar system could easily swap places, but where the sun's influence still reigns supreme.
"We have no explanation for why we even found this new region," Burlaga told Reuters.
So far, Voyager's sister probe, Voyager 2, which is exiting the solar system in a different direction, has not encountered the same phenomena - nor may it ever.
"Voyager 2 has seen exactly what the models predicted we would see, unlike Voyager 1, which didn't," said lead scientist Ed Stone, with the California Institute of Technology in Pasadena, California.
Voyager 1 may be in an unusual place where the heliosheath and interstellar space connect, he added.
Voyager 1 is now about 11 billion miles (18 billion km) from Earth. At that distance, it takes radio signals, which move at the speed of light, 17 hours to make a one-way trip to Earth.
Scientists do not know how much farther Voyager has to travel to reach interstellar space. The spacecraft, which is powered by the slow decay of radioactive plutonium, will begin running out of energy for its science instruments in 2020. By 2025, it will be completely out of power. 

 

A total of 11,000 workyears was devoted to the Voyager project through the Neptune encounter.
The arrangement of Jupiter, Saturn, Uranus and Neptune at the time of launch,  allowed the V-1 qnd V-2  to swing from one planet to the next with the minimum of fuel. “The flyby of each planet bends the spacecraft's flight path and increases its velocity enough to deliver it to the next destination”   
In search of intelligent beings there is a gold plated audio disc with messages in fifty five languages and various earthly sounds.
Jupiter's Moons:
Flying past Amalthea, Io, Europa, Ganymede and Callisto on 5 March, V-1 returned spectacular photos of their terrain,.It found five new moons and a ring system consisting of thousands of bands, discovered a new ring  G, and found  satellites that keep the rings well defined. During its flyby, the it photographed Saturn's moons Titan, Mimas, Enceladus, Tethys, Dione, and Rhea. Plenty of ice has been detected.V- 1 passed Titan which had a thick atmosphere that completely hid the surface which was composed on 90 % nitrogen. The Pressure and temperature at the surface was 1.6 A, and -180° C, respectively.
                                                        Source: NASA

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