Join Us Now!
Grandy, post: 10257100, member: 179113 Wrote:Is China's space laser for real?
It's not a Death Star super laser. It's a space broom.
By Jeffrey Lin and P.W. Singer Yesterday at 11:50pm
It's not this. China's space broom isn't the Death Star super laser. It's an orbiting satellite with a laser only powerful enough to heat up pieces of space junk, so that they change course burn up in the atmosphere. Depositphotos
In a recent article in scientific journal Optik, a faculty member at China's Air Force Engineering University proposed building a laser-armed satellite, a "broom" to do battle with the pernicious problem of space debris.
Laser-armed satellites, naturally, generate a lot of attention, and so the proposal of Quan Wen and his co-authors has made its way into several splashy headlines. But it's more than hype. The concept addresses a real (and growing) problem: there's something like 17,852 artificial objects orbiting earth (PDF), and an estimated 300,000-plus pieces of space debris larger than a marble. At the fast orbital velocities up in space, even large craft like the International Space Station have to maneuver out of the way of small objects to avoid catastrophic damage.
Quan's research looks at the efficacy of a hypothetical laser operating near the infrared spectrum. It would blast away targeted space debris for a couple minutes, at a rate of twenty bursts of laserfire a second. That amount of energy would be sufficient to vaporize part of the object's mass. Contrary to public imagination, space laser brooms like the one proposed don't actually vaporize space debris, but rather "burn off" a chunk. This would create sufficient kinetic force from the chemical combustion to change the object's orbit. With that change in direction, the debris will quickly reenter the atmosphere and burn up. Because of atmospheric distortion, it's much more effective to zap space debris with a satellite than, say, a ground-based laser.
Of course, for now it's all theory. The laser broom would need to be actually mounted on a satellite and lofted into orbit to test its true efficacy. And even then, it'd still face some legal grey areas (technically speaking, space debris are still the property of owners of the satellites they originated from, which is very, very difficult to track) as well as major suspicion about the idea of implementing a weapon-like technology up in space.
Like many others, China's space program has both civilian and military applications. (The AoLong 1 satellite, for example, has a robotic arm for mechanically de-orbiting space debris that has has potential as an anti-satellite sabotage technology.) And so there's an obvious question: can the space laser broom be an anti-satellite weapon? It's certainly possible, though a cost-effective laser broom would need to be small—just big enough to take care of small debris. To quickly deal serious damage to enemy spacecraft, one would need a much larger space laser weapon; perhaps an orbital battlemoon?
Peter Warren Singer is a strategist and senior fellow at the New America Foundation. He has been named by Defense News as one of the 100 most influential people in defense issues. He was also dubbed an official "Mad Scientist" for the U.S. Army's Training and Doctrine Command. Jeffrey is a national security professional in the greater D.C. area.
Solomon2, post: 10305257, member: 12445 Wrote:Has There Been a Loss of Control?
Where will Tiangong-1 reenter?
How Difficult is it to Accurately Predict a Reentry?
Will objects from this reentry hit me or my property?
https://archive.ph/IA7wV/0ce1b3b251ae36e...a73968.jpg ; https://archive.ph/IA7wV/df80d692f622f81...fd/scr.png ; http://web.archive.org/web/2019112520231...emoisa.jpg ; https://defence.pk/pdf/attachments/point...8e3ef7f07a
▲ 2. Official designated reentry area for Tiangong-1: 'Point Nemo' is a watery graveyard for titanium fuel tanks and other high-tech space debris.
One place China's Earth-bound and out-of-control spacelab, Tiangong-1, will probably not hit on Sunday is the forlorn spot in the southern Pacific Ocean where it was supposed to crash.
Officially called an "ocean point of inaccessibility," this watery graveyard for titanium fuel tanks and other high-tech space debris is better known to space junkies as Point Nemo, in honour of Jules Verne's fictional submarine captain.
Point Nemo is further from land than any other dot on the globe: 2,688 kilometres (about 1,450 miles) from the Pitcairn Islands to the north, one of the Easter Islands to the northwest, and Maher Island—part of Antarctica—to the South.
"Its most attractive feature for controlled re-entries is that nobody is living there," said Stijn Lemmens, a space debris expert at the European Space Agency in Darmstadt, Germany.
"Coincidentally, it is also biologically not very diverse. So it gets used as a dumping ground—'space graveyard' would be a more polite term—mainly for cargo spacecraft," he told AFP.
Some 250 to 300 spacecraft—which have mostly burned up as they carved a path through Earth's atmosphere—have been laid to rest there, he said.
By far the largest object descending from the heavens to splash down at Point Nemo, in 2001, was Russia's MIR space lab, which weighed 120 tonnes.
"It is routinely used nowadays by the (Russian) Progress capsules, which go back-and-forth to the International Space Station (ISS)," said Lemmens.
The massive, 420-tonne ISS also has a rendezvous with destiny at Point Nemo, in 2024.
In future, most spacecraft will be "designed for demise" with materials that melt at lower temperatures, making them far less likely to survive re-entry and hit Earth's surface.
Both NASA and the ESA, for example, are switching from titanium to alumium in the manufacture of fuel tanks.
China hoisted Tiangong-1, it's first manned space lab, into space in 2011. It was slated for a controlled re-entry but ground engineers lost control in March 2016 of the eight-tonne craft in March 2016, which is when it began its descent toward a fiery end.
The chances of anyone getting hit by debris from Tiangong-1 are vanishingly small, less than one in 12 trillion, according to the ESA.
"Nemo," by the way, means "no one" in Latin.
Quote:Yang-Sui (阳燧) Solar Ignitor, World’s Oldest Solar Device
During the sixth century BCE, Confucius wrote about the common use of curved mirrors shaped from shiny metal to concentrate the rays of the sun for making fire. These became known as yang-suis – translating to solar ignitors, or burning mirrors.
According to the great philosopher, upon waking up the eldest son would attach a solar ignitor to his belt as he dressed for the day. It was his duty to focus the solar rays onto kindling to start the family’s cooking fire.
According to another early text, the Zhouli, which describes rituals dating far back into Chinese antiquity, “The Directors of the Sun Fire have the duty of transferring with burning mirrors the brilliant flames of the sun to torches for sacrifice.”
Although scholars found over the years many ancient texts discussing solar ignitors, the discovery of an extant yang sui eluded them for centuries. Quite recently came the Eureka moment. Digging up a tomb that dated to about 3,000 years ago, a team of archaeologists found in the hand of a skeleton a bowl-shaped metal object. While the inner side could have passed for a wok, the exterior trough had a handle in its center. That’s what caught the eye of the two archaeologist in charge of the dig, Lu Demming and Zhai Keyong. They immediately brought the relic back to the local museum and ordered its specialists to make a mold from the original and then cast a copy in bronze.
After polishing its curved surface to a high degree of reflectance, the inquisitive archaeologists focused sunlight onto a piece of tinder just as the eldest son would have done so many years past, and in seconds the combustible material burst into flames. “This verified without a doubt that the purpose of the artifact is to make fire,” Lu and Zhai later wrote, assured of having found the oldest solar device in the history of humanity.
Now that the world could see what a real yang-sui looked like, museums retrospectively identified 20 more previously unclassified objects as solar ignitors. Multiple molds for turning out yang suislater found at a Bronze Age foundry in Shanxi province, close to the first find, suggest a mass market once existed for them. In fact, yang suis were probably as ubiquitous in early China as are matches and lighters today. The yang sui “should be regarded as one of the great inventions of ancient Chinese history,” remarked its discoverers, impressed by the ability of their forefathers to figure out the complex optics for such optimal performance so early in time.
https://archive.ph/ey1j1/7761884ee427158...250a3a.jpg ; https://archive.ph/ey1j1/953b1ac6915220f...ee/scr.png ; http://web.archive.org/web/2019112521572...b9g215.jpg ; http://web.archive.org/web/2017101823035...66592.html ; http://archive.ph/hfNt7 ; https://defence.pk/pdf/attachments/u1317...d52999bfae
▲ 11. Yang-Sui (阳燧) Solar Ignitor
https://archive.ph/UZEe0/7b150484da8519c...7ac86b.jpg ; https://archive.ph/UZEe0/db35ee202f3c4a5...24/scr.png ; http://web.archive.org/web/2019112522181...7QliLq.jpg ; http://web.archive.org/web/2017071720322...7yoV6K.jpg ; http://s9.sinaimg.cn/mw690/001n7IPZzy6SUaPoNjWc8&690 ; http://blog.sina.com.cn/s/blog_4af8f35f0102vkmc.html ; http://archive.ph/0FVDy
▲ 12. Yang-Sui (阳燧) Solar Ignitor
https://archive.ph/mfkkF/1ebe82fc3aef6a5...4e7215.jpg ; https://archive.ph/mfkkF/86a1523cf9c14ef...71/scr.png ; http://web.archive.org/web/2019112522282...c3ny6S.jpg ; http://ipic.su/7yoV6M.jpg ; http://s3.sinaimg.cn/mw690/001Myf17zy6TZcD1TkC82&690 ; http://blog.sina.com.cn/s/blog_615e1d510102vmlx.html ; https://defence.pk/pdf/attachments/7yov6...d52999bfae
▲ 13. Yang-Sui (阳燧) Solar Ignitor
https://archive.ph/xQ5fV/0f2fbdd1afd64d2...ed8da6.jpg ; https://archive.ph/xQ5fV/bb4f16a30fed24e...86/scr.png ; http://web.archive.org/web/2019112522340...f16dbc.jpg ; http://archive.ph/60kKO ; http://web.archive.org/web/2019112522321...are_p.html ; https://defence.pk/pdf/attachments/9dd4a...78e7f2f421
▲ 14. Flashforward: Korean-style Gigantic Yang-Sui (阳燧) Solar Ignitor?
Quote:Descent of China’s Tiangong-1 will not cause damage to earth: expert
March 14, 2018
According to the latest information issued by China’s manned space engineering office, since Feb. 25 to Mar. 4, 2018, Tiangong-1 was orbiting in stable condition and good shape at an average height of about 251.5 kilometers (perigee height: 238.6 km; apogee height: 264.4 km; orbital inclination: 42.79 degrees).
China has been monitoring Tiangong-1, Zhu said, adding that the space lab will burn up after entering the atmosphere and the remaining wreckage will fall into a designated area of the sea, without endangering the Earth’s surface.
Aerospace expert Pang Zhihao explained that an international tradition to handle retired large spacecrafts operated at near-earth orbits is to let them fall to an abyssal zone in southern Pacific Ocean far away from the continents.
Being called the “graveyard of spacecraft”, the water was the falling location for Mir space station and Progress spacecraft of Russia, and the Compton Gamma Ray Observatory of the US, Pang added.
Quote:We can grasp the mightiness of China, a great neighboring country. More excellent scientific successes will be achieved under the wise leadership of the Communist Party of China.
Kim Jong Un on March 27, 2018.