January 5 


5 January 1905

 

Two minute exposure of Jupiter's moon Elara with a 24" telescope. Credit: Kevin Heider 


Elara (Jupiter VII), a prograde irregular satellite of Jupiter, was discovered on January 5, 1905, by Charles Dillon Perrine (1867–1951) in photographs taken on January 2, 3 and 4, 1905, at the Lick Observatory on Mount Hamilton at the University of California, San Jose. The images were taken with the 36-inch (0.9 meter) Crossley reflector telescope that Perrine had recently rebuilt. However, poor weather conditions delayed the confirmation of the discovery till the 21st of February.

   Elara is the eighth largest moon of Jupiter. It has a diameter of about 80 km and belongs to the Himalia group of Jupiter's moons. At a distance of about 11.7 million km from Jupiter, Elara takes nearly 260 days to complete one orbit. Elara may be a chunk of an asteroid (a C- or D-class asteroid, judging by the fact that it reflects only about 4 percent of the light it receives), which was broken apart in a collision either before or after being captured by Jupiter's gravity. In this scenario, the other pieces became the other moons in the Himalia group: Leda, Himalia (the largest), and Lysithea.

   The moon is named for one of the lovers of Zeus, the Greek equivalent of the Roman god Jupiter.
 
Charles Dillon Perrine. Credit: Special Collections UC Santa Cruz
 
 
© 2026, Andrew Mirecki
 

 

5 January 1969


Preflight preparations of Venera 5. Credit: NPO Lavochkin

Venera 5 spacecraft was launched from Baikonur on January 5, 1969, at 06:28:08 UTC, on a Molniya 8K78M launch vehicle. Its lander capsule entered the Venusian atmosphere on May 16, 1969.
 
   Venera 5 and Venera 6 spacecraft were of identical design and launched 5 days apart in January 1969. The spacecraft were designed to make in-situ measurements as they descended through the Venusian atmosphere. Measurements included temperature, pressure, and composition. 
 
   Venera 5 spacecraft was very similar to Venera 4 although it was of a stronger design. It comprised a bus with a mass of 1130 kg which held the descent probe. The probe was spherical with a mass of 405 kg and was designed for decelerations as high as 450-g. Venera 5 and 6 were designed with smaller parachutes (15 square meters) than Venera 4 to allow them to fall faster so as to get lower in the atmosphere while still operational. The top of the probe would be ejected to deploy the parachute and expose the instruments to the atmosphere. The probe carried a radio altimeter, two resistance thermometers, an aneroid barometer, eleven gas analyzer cartridges, an ionization densitometer, and photoelectric sensors. The probe also carried a medallion bearing the coat of arms of the U.S.S.R. and a bas-relief of V.I. Lenin to the night side of Venus.

   The bus was essentially identical to the Venera 4 bus. It was 3.5 meter high and powered by 2.5 square meters of solar panel "wings" with a span of 4 meters. A 2.3 meter diameter high-gain parabolic dish antenna was mounted on the cylinder facing opposite the solar panels and a cone-shaped omni-directional antenna was mounted at the end of one of the solar panels. There was a large rocket for mid-course maneuvering, and a set of smaller thrusters, with Sun, Earth, and star sensors, for attitude control. Communications from the probe were achieved by two 1 bit/sec transmitters in the DM waveband. The bus held energetic particle detectors, charged particle traps, and an ultraviolet photometer.  
 
© 2026, Andrew Mirecki
 
 
 

5 January 1972

 
President Nixon (right) and NASA administrator Dr. James Fletcher discuss the Space Shuttle in San Clemente, California. Credit: NASA
 
On January 5, 1972, president Richard Nixon (1913–1994) announced the formal decision to develop the Space Shuttle. 

Statement by President Nixon:
 
"I have decided today that the United States should proceed at once with the development of an entirely new type of space transportation system designed to help transform the space frontier of the 1970’s into familiar territory, easily accessible for human endeavor in the 1980’s and ’90’s.

This system will center on a space vehicle that can shuttle repeatedly from Earth to orbit and back. It will revolutionize transportation into near space, by routinizing it. It will take the astronomical costs out of astronautics. In short, it will go a long way toward delivering the rich benefits of practical space utilization and the valuable spinoffs from space efforts into the daily lives of Americans and all people..."

A Space Shuttle lifts off in this August 1, 1973, artist's illustration. Credit: NASA

   Each Space Shuttle consisted of three major components: the orbiter, which housed the crew, a large external tank that held fuel for the main engines, and two solid rocket boosters that provided most of the shuttle’s lift during the first two minutes of flight. All the components were reused except for the external fuel tank, which burned up in the atmosphere after each launch. The space shuttle was the world’s first reusable spacecraft. The Space Shuttle Columbia made its maiden flight in 1981.

 
© 2026, Andrew Mirecki
 
 
 

5 January 2005

 
Image of Eris and its moon, Dysnomia, taken with the Hubble Space Telescope. Credit: NASA, ESA, and M. Brown (California Institute of Technology)

Dwarf planet (136199) Eris was discovered on January 5, 2005, from data obtained on October 21, 2003, using the Samuel Oschin Telescope at the Palomar Observatory, California. Its discovery was made during survey of the outer solar system by Mike Brown (b. 1965), a professor of planetary astronomy at the California Institute of Technology; Chad Trujillo (b. 1973) of the Gemini Observatory; and David Rabinowitz (b. 1960) of Yale University.
 
   Eris is a scattered-disk object with an orbital period of 559 years, a perihelion 38.3 au and an aphelion 97.5 au. With a diameter of about 2,300 km, it is the most massive and second-largest known dwarf planet in the Solar System. It has a large moon about 700 km in diameter, named Dysnomia. 
 
   The discovery of Eris help trigger a debate in the scientific community that led to the International Astronomical Union's decision in 2006 to clarify the definition of a planet. Pluto, Eris, and other similar objects are now classified as dwarf planets. 
 
Discovery images of Eris taken on Oct. 21, 2003: NASA/JPL/Caltech

 
© 2026, Andrew Mirecki

 
 
 

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