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.
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.
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 | |
| | 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
