Latestvibe, Science
The US equivalent to a Soviet Union satellite equipped with a nuclear reactor is the radioisotope thermoelectric generator or RTG. An RTG is a nuclear reactor type electrical generator. The heat released from the radioactive decay of a specified radioactive element in the device is converted into electricity and used for power.
Thus, RTGs can be considered as a type of battery, and have been used as power sources in satellites, space probes and other unmanned remote facilities (such as a series of lighthouses built by the former Soviet Union inside the Arctic Circle).
RTGs are used where solar cells are not practical and power usage is longer than that which can be provided by fuel cells. A common application of RTGs is as power sources on spacecraft such as Voyager 1, Voyager 2 and Galileo. In addition, RTGs were used to power scientific experiments left on the Moon by the crews of Apollo 12 through 17 (except Apollo 13, as we will see).
RTGs may pose a risk of radioactive contamination: if the container holding the fuel leaks, the radioactive material may contaminate the environment. For spacecraft, the main concern is that if an accident were to occur during launch or a subsequent passage of a spacecraft close to Earth.
One such incident took place on April 21, 1964, when a Transit-5BN-3 navigation satellite failed to reach orbit when launched. The spacecraft burned up over Madagascar and the plutonium fuel in the RTG was injected into the atmosphere over the Southern Atlantic Ocean. Traces of the Plutonium were detected in the atmosphere as a result.
Science, Technology
RORSAT, meaning Radar Ocean Reconnaissance Satellite, is the western term used to describe a series of Soviet Union satellites.
These satellites were launched between 1967 and 1988, to monitor NATO and merchant vessels using radar.
They were referred to as Cosmos satellites and carried type BES-5 nuclear reactors fueled by uranium-235.
For the radar to work efficiently the satellites were placed into low Earth orbit. The plan was for the spacecraft to jettison the reactor into high Earth orbit when the satellites effective life had ended.
However, there were several failures.One such failure was Cosmos 1402. At the end of the satellites intended operational period, the reactor did not separate into high Earth orbit as planned.
When the satellite reentered the atmosphere on February 7, 1983, the reactor was the last piece to come home to Earth. It landed somewhere in the South Atlantic Ocean.
Latestvibe, Science
Dwarf galaxies are tiny but incredibly potent, showing us on a cosmic scale that size doesn’t matter—it’s how you use it that counts.
Astronomers have previously performed astronomical surveys to ascertain the rate of star formation in mid- and high-mass galaxies, but not until recently did they study the smallest ones.
And so they peered eight billion years into the past to determine a relationship between galactic mass and star-forming prowess.After Hubble had glimpsed the miniscule galaxies in infrared, astronomers were surprised to find that the dwarfs produced stars at a much faster rate than their larger, more massive brethren.
That’s quite shocking, since you’d expect more gas to equal more stars. However, the tiniest galaxies proved the most productive with an ability to double up their cache of stars in only 150 million years. In a normal-sized galaxy, such growth would require between one and three billion years of hard gravitational work.
Sadly, astronomers don’t know why the dwarfs are so prolific, but they hope to pry their secrets open as they discover similar specimens at different points in their evolution.
Latestvibe, Science
Carried aboard a pimped-out Boeing 747SP jumbo jet, NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, does most of its (her?) work at 12,000 meters (40,000 ft) and above.
Up here, there’s little atmospheric water vapor to distort measurements, and NASA gets a much clearer view of the cosmos. Recently, SOFIA earned its keep by helping astronomers solve a cosmic mystery.
As you know if you’ve watched any space show ever, stellar material is the basis of humans and everything else in the universe.
But it was unclear how these tiny grains of stardust avoided vaporization at the hands of the supernovae that distribute them throughout the universe.
Peering deep into the 10,000-year-old Sagittarius A East supernova remnant with its infrared eyes, SOFIA discovered that dense regions of gas around the star cushion cosmic dust particles.
This prevents their eradication as they rebound from the massive shockwave of the preceding blast.
Even though only 7–20 percent of the dust around the Sagittarius A East managed to survive obliteration, this is still enough to birth around 7,000 Earth-sized bodies.
