co orbiting

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Despite the possibilities offered by the large dual-keel station, by 1987-88 it was becoming apparent that the station would be too expensive to construct, both in terms of shuttle missions and spacewalks.  Congress balked at the price tag and the station was redesigned to be more affordable and easier to build.

To this end, the second keel was deleted from the design, and the core modules were reduced to “1 Lab, 1 Hab”.  Accordingly, the Japanese Experiment Module and ESA Columbus Laboratory were moved into center of the configuration.  (Columbus was still a full-sized module.)  The PMM now hangs below the central nodes with the airlock on top.  The co-orbiting platform for microgravity experiments has been deleted, though the polar orbiting platform was retained.  An ACRV (Assured Crew Return Vehicle) was added to the design after the Challenger accident, in case a shuttle was unavailable to return a crew.

Unfortunately, Space Station Freedom was heading into the 90′s in serious trouble and the project came to a head in 1990 when a review found the station overweight, underpowered, and extremely complicated to assemble, requiring up to 3,276 hours of spacewalks to assemble the trusses and other equipment.

It was time to go back to the drawing board and revise the design again…

Another brief design was this “Delta Station” concept.  Incorporating the satellite dry dock into the area between the trusses created a very stable structure.  

However, research showed that the number of spacewalks needed to assemble the trusses would be… extreme.  (at this point, station trusses were not prefabricated as on the ISS, rather assembled by hand by Astronauts in space)

Also visible is one of the science co-orbital platforms.  For a time, the space station was to have free-floating platforms to house sensitive microgravity experiments.

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Throwback Thursday: Earth’s second moon?

“So no, we don’t quite have a second moon, but we do finally have a robust discovery of a Trojan asteroid to call our very own. And it isn’t 3753 Cruithne; don’t be fooled. 3,000 years is nothing in the life of our Solar System. When it comes to Trojans, stick with the one that will stick with us, and that’s 2010 TK7!”

Planets can have not only moons, but gravitationally captured bodies co-orbiting the Sun either ahead or behind them in orbit. Jupiter, for example, has not only all the moons that orbit around it, but thousands of gravitationally captured objects in addition: the Trojans (and Greeks). While Earth may have only one true moon orbiting our world, what of these Trojans? Do we have any captured asteroids or comets hanging out around one of our Lagrange points? We absolutely do, but only one of them is here to stay, and it very likely isn’t the one – 3753 Cruithne – you’ve heard of

Two Black Holes Dancing in 3C 75 : What’s happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets’ consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources of gravitational waves. via NASA

Comet Churyumov Gerasimenko in Crescent

Image Credit: ESA, Rosetta, NAVCAM; processing by Giuseppe Conzo

Explanation: What’s happening to Comet 67P/Churyumov–Gerasimenko? As the 3-km wide comet moves closer to the Sun, heat causes the nucleus to expel gas and dust. The Rosetta spacecraft arrived at the comet’s craggily double nucleus last July and now is co-orbiting the Sun with the giant dark iceberg. Recent analysis of data beamed back to Earth from the robotic Rosetta spacecraft has shown that water being expelled by 67P has a significant difference with water on Earth, indicating that Earth’s water could not have originated from ancient collisions with comets like 67P. Additionally, neither Rosetta nor its Philae lander detected a magnetic field around the comet nucleus, indicating that magnetism might have been unimportant in the evolution of the early Solar System. Comet 67P, shown in a crescent phase in false color, should increase its evaporation rate as it nears its closest approach to the Sun in 2015 August, when it reaches a Sun distance just a bit further out than the Earth.

(NASA)  Two Black Holes Dancing in 3C 75
Image Credit: X-Ray: NASA/CXC/D. Hudson, T.Reiprich et al. (AIfA); Radio: NRAO/VLA/ NRL

What’s happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets’ consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources of gravitational waves.

The Real Star Wars

The Growing Risk of a War in Space

One of the most ominous implications of co-orbital anti-satellite warfare is the difficulty of determining what is—or is not—a weapon. Indeed, as military journalist David Axe has written, “It’s hard to say exactly how many weapons are in orbit … With the proverbial flip of a switch, an inspection satellite, ostensibly configured for orbital repair work, could become a robotic assassin capable of taking out other satellites with lasers, explosives or mechanical claws. Until the moment it attacks, however, the assassin spacecraft might appear to be harmless.” This raises the prospect of long-duration sleeper weapons already in orbit, their actual military purpose yet to be revealed. They are weapons-in-waiting.

(Photo credit: NASA/The Atlantic)