Skyborne whales: The rise (and fall) of the airship
Can passenger airships make a triumphantly 'green' comeback?
Large airships were too sensitive to wind gusts and too sluggish to win against aeroplanes. But today, they have a chance to make a spectacular return.
This trend brings with it the unique opportunity for the much more environmentally-friendly passenger airships to make a triumphant comeback. Much like they did 100 years ago, today's airships move with the help of propeller-type turbines powered by petrol or diesel engines. However, they emit considerably less CO2 than jet engines. On shorter distances, their speed, on average nine times lower than passenger jets, does not make that much of a difference. Especially since an airship can pick up passengers even in the centre of a metropolis.
Working on refining such a solution is the British company Hybrid Air Vehicles (HAV), founded in 2007. For the past decade, its engineers have been fine-tuning the Airlander 10 project. Standing behind the name is a 92-metres-long vehicle that combines the benefits of an aeroplane and helicopter. It can land and take off from practically any location, take 14 tons of cargo or 60 passengers on board, and then fly at a speed of 140 kilometres per hour for up to five days without having to land. In September 2019 in London, HAV representatives signed a contract with the US company Vertex Aerospace LLC, thereby opening up the possibility of supplying Airlander 10 to the US Department of Defense. Soon after that, the management of HAV announced it was launching preparations for the development of a passenger model powered by electric engines. It is indeed this type of drive unit that could ultimately tip the scales and let these huge machines, the development of which was halted by aeroplanes 100 years ago, take to the skies once more.
A balloon with an engine
The balloon designed and built by Joseph and Jacques Montgolfier never became a useful flying machine due to one fundamental drawback: the direction that it flew in was defined by the blowing wind. For several decades since the summer of 1783, when the brothers held a demonstration of their invention for King Louis XVI by sending a lamb, rooster and duck flying in the air, designers were not be able to overcome this challenge. Granted, there were designs of balloons equipped with sails or even propellers, yet the secret to success lay in a proper drive unit.
French designer Henri Jules Giffard was the first to recognize this. He managed to build a steam engine weighing a little over 100 kilograms that could be installed in the balloon's gondola. He attached his structure to a cigar-shaped balloon 44 metres in length and filled it with hydrogen. Then he loaded 150 kilograms of coke into the gondola and, on 24th September 1852, set out from Paris to Trappes. The flight proceeded in the direction chosen by Giffard, as the French inventor equipped the vehicle with a triangular sail serving the function of a rudder. Yet the flying giant proved to be helpless in the face of slightly stronger gusts of wind. And once again, the problem lay in the drive unit; to be able to squeeze additional power out of a steam engine, it had to be enlarged. That, in turn, meant that the balloon needed to be bigger to be able to lift the heavier load into the sky. But then the vessel would become even less controllable and vulnerable to the wind.
Numerous designers attempted to improve Giffard's masterpiece. An airship designed by two captains of the French Army, Charles Renard and Arthur Krebs, looked very promising. The propeller that pushed the vehicle forward was powered by an 8.5 horsepower electric engine, eight times more powerful than Giffard's steam engine. Thanks to the new drive unit, on 9th August 1884, La France was able to fly eight kilometres in 20 minutes, turn back and return to the place it started from, in spite of the wind. However, Krebs and Renard were not able to manage the issues created by lead acid batteries, as they were too heavy, inefficient and required constant recharging.
The flying count
While French inventors were walking in circles, the Germans set off to conquer the heavens. At the end of the 19th century, Germany was producing the most sophisticated combustion engines in the world. The small yet powerful 28 horsepower engines from the Daimler factory caught the attention of Count Ferdinand von Zeppelin. In 1890, with his 50th birthday on his heels, General von Zeppelin decided to end his military career and engage in the construction of flying machines, thereby fulfilling the dreams of his youth. He caught the aeronautics bug in the US during the Civil War, when he flew in a balloon high above the battle fields as the envoy of the King of Württemberg. 25 years later, he started work on the construction of an innovative airship along with engineer Theodor Kobert. They drew inspiration from the ideas of Hungarian engineer David Schwartz, who had patented the design of an aerostat based on a stiff frame covered with a cotton or aluminium shell, which in turn concealed soft balloons filled with hydrogen.
The fulfilment of his dream proved to be a costly venture, and after eight years of struggling, Von Zeppelin founded the Gesellschaft zur Förderung der Luftschiffahrt in Stuttgart in 1898. In July 1900, on the coast of Lake Constance, he was able to present to shareholders and onlookers his enormous flying machine, the Luftschiff Zeppelin (LZ 1). The cigar-shaped creation, which was 128 metres in length, majestically glided across the sky around 300 metres above the waters of the lake thanks to two Daimler engines. Following that success, and thanks to public fundraisers and lotteries, Von Zeppelin managed to collect 250,000 marks to build yet another airship, abbreviated the LZ 2. The count was expecting that the German army would buy it for 1.5 million marks, but the price proved to be prohibitively high. The army was initially not interested in the LZ 3 model either, although it made 45 flights safely, covering an air distance of 4000 kilometres.
A breakthrough did not come until the matter of the high-profile catastrophe of the LZ 4 airship appeared. The count had turned the LZ 4 into a near masterpiece. The 136-metre-long cigar-shaped vehicle was divided into 17 chambers filled with hydrogen, and attached beneath it was a gondola for the pilots and mechanics, as well as a second luxury passenger gondola. Even King Wilhelm II of Württemberg, who had been persuaded to try the airship out in July of 1908, had no complaints about its level of comfort. After the marketing success, Count Zeppelin announced that his vehicle would make a 24-hour flight without landing, hoping to convince the head of the German army that airships were the perfect solution for attacking the deep hinterland of the enemy. However, on 5th August 1908, a storm forced the LZ 4 pilot Hugon Eckener to land near the city of Echterdingen. There, a gust of the storm wind snapped the airship's tether and threw it to the ground; the hydrogen exploded and the machine burned to ashes.
That loss pushed Count Zeppelin's company to the brink of bankruptcy. When the news became widespread, the Germans spontaneously organized a fundraiser for the engineer, whom they were proud of. Soon, he received a sum of over six million marks. This capital allowed Zeppelin to found Luftschiffbau Zeppelin GmbH, a company that, in line with its name (Luftschiffbau means 'airship engineering'), specialized in the construction of airships. Financial aid was also promised by the Minister of War Karl von Einem, who was increasingly more interested in the combat potential of the flying machines.
Civil and bomber
The mass participation of regular Germans in the fundraiser gave Von Zeppelin the idea that his airships could compete with train travel. In November 1909, he surprised the world by founding the Deutsche Luftschiffahrts Aktiengesellschaft (DELAG) passenger airline. DELAG transported the first 20,000 passengers for free, thereby promoting the trend for air travel, and after that he offered tickets for 200 marks. The amount was equivalent to average monthly wages in Germany at the time; nonethless, its flights were becoming more and more popular. On board the 12 DELAG airships, servicing routes connecting the 10 largest cities of the German Empire, you could travel in the company of aristocrats, politicians, millionaires, generals, or even members of the Imperial Family. In 1914, the airline proudly announced that it had transported 34,000 passengers, and that not one of them died during the flights. Users of highly unreliable aeroplanes could only dream of such statistics at the time.
So when World War I broke out, as the late Walter J. Boyne wrote in his book The Influence of Air Power Upon History, "Germany was so convinced of the potential of dirigibles [...] that it allowed the Army and the Navy to develop their own airship fleets [...]." Ferdinand von Zeppelin, now nearing 80 years of age, was at the height of his fame, while his factories were working at full capacity. Right after the airships, commonly referred to as Zeppelins, appeared over the front lines in France and Great Britain, they raised alarm. In September 1914, in an attempt to anticipate any actions of the enemy, the First Lord of the Admiralty Winston Churchill planned a series of attacks of British bombers on airship bases in Cologne and Düsseldorf, and on an airship manufacturing plant in Friedrichshafen. Despite the great dedication of the airmen, the action brought little effect, as only one Zeppelin burned down on the ground when it was hit by a bomb. Yet the expected retaliation attacks did not take place right away. "At a joint meeting September 1914, representatives of the Army and Navy decided that there were as yet too few airships to bomb England, and further, that they were inhibited by Kaiser Wilhelm's reluctance to bomb the homes of many of his royal relatives," Boyne explains. It wasn't until Germany realized enormous losses on the front that the monarch changed his mind.
"The first attack took place on January 19-20, 1915, with two out of three Zeppelins – L 3 and L 4 – successfully reaching England," Boyne describes. L 3 dropped over a dozen 50-kilogram bombs on Great Yarmouth, while L 4, led by Captain Magnus von Platen-Hallermund, nearly gave the German Emperor a heart attack. Its bombs fell onto Sandringham House, where the cousin of Wilhelm II, the British King George V, happened to be staying at the time. Luckily nothing happened to him, but the public were shocked by the fact that for the first time in 800 years, since the times of William the Conqueror, an enemy from the continent had launched a direct attack on the monarchs of England.
At first, the airships operated over the island with complete impunity. Rifle bullets shot from the ground were not able to pierce the duralumin sheeting of the vessels' hulls. In addition, Zeppelins flew at higher altitudes than fighter planes and were able to climb up more quickly, in spite of their large dimensions. For the first time ever in history, Lieutenant Reginald Warneford managed to shoot down the L 37 airship, but this was only after he flew above it in a plane and dropped six bombs from the top. Therefore, the Germans used them even more boldly. "All the fears seemed to be realised on the night of October 13-14 [1915], when five Zeppelins slashed across England, dropping almost two hundred bombs and killing seventy-one people and injuring another 128," Boyne reports.
The blind path of evolution
"Looking up the clear run of New Bridge Street and Farringdon Road I saw high in the sky a concentrated blaze of searchlights, and in its centre a ruddy glow which rapidly spread into the outline of a blazing airship. Then the search lights were turned off and the Zeppelin drifted perpendicularly in the darkened sky, a gigantic pyramid of flames, red and orange, like a ruined star falling slowly to earth," are the words reporter Michael MacDonagh noted in his journal entry dated 1st October 1916. "It was so horribly fascinating that I felt spellbound – almost suffocated with emotion, ready hysterically to laugh or cry. When at last the doomed airship vanished from sight there arose a shout the like of which I never heard in London before – a hoarse shout of mingled execration, triumph and joy; a swelling shout that appeared to be rising from all parts of the metropolis, ever increasing in force and intensity," he added. A month earlier, right after midnight on 3rd September 1916, London experienced the 'Night of the Zeppelins', when as many as 16 dark cigars hovered over the British capital, each 200-metres long and each dropping bombs to the ground. They seemed to be mighty and impregnable, yet as a result of the wartime arms race, planes and anti-aircraft artillery was being perfected at an amazing pace. A few months down the line, all you needed to take down an airship was an accurately launched machine gun series with ammunition designed to puncture the aluminium shell, or a few artillery shells. When British fighter planes shot down 17 Zeppelins in 1917, the Germans backed out of the London bombings.
The bombs dropped by the airships killed 557 British subjects and caused material damage amounting to $7.5 million. Yet the construction of 17 Zeppelins cost $8.3 million, and over 300 crew members were lost. From a military and economic perspective, the balance was disastrous. Nevertheless, in the Versailles Treaty, the triumphant superpowers prohibited the production of airships in the Weimar Republic.
Fortunately, Ferdinand von Zeppelin did not live to see that day, as he had died in 1917. His successor at Luftschiffbau Zeppelin GmbH, Hugo Eckener, initiated long-term lobbying efforts in the US that lasted until 1922, when American President Warren G. Harding stated that it would be an excellent idea for Germany to pay out part of the war reparations due in brand new airships. London and Paris did not protest to this. In the meantime, engineers had developed a new generation of machines. The first LZ 120 series airship 'Bodensee' had the shape of a 120-metre-long 'teardrop', which was able to fly at a speed of 130 kilometres per hour thanks to four Maybach engines with 245 horsepower each. An improved version of the 'Bodensee', the LZ 127 'Graf Zeppelin', was extended to 236 metres. As a result, it allowed engineers to achieve a significant increase in lift, to the point where in 1929, humanity could follow the flight of the 'Graf Zeppelin' around the world with fascination. At the time, the press was all over the topic of its comfortable cabins for 40 passengers, which were even equipped with separate toilets and showers with hot water, a luxurious restaurant and a lounge, indispensable for evening receptions.
But not too long after that, the factories of William E. Boeing in Seattle started to offer to airlines its innovative passenger aeroplane model, the B 247; it was a beautiful twin-engine machine able to fly at speeds of over 300 kilometres per hour. It provided a sound-proof cabin for 10 passengers with the possibility of controlling the temperature. But it didn't outbid the offer of luxurious airships just yet; the decisive factor in this new race was... gas. German engineers replaced the flammable hydrogen with the much safer helium. They had to buy it from the Americans though, as only they had the technology available to produce helium on an industrial level. When Hitler came to power in Germany, fears were increasingly expressed across the Atlantic that a fleet of combat airships could launch an unexpected attack on American cities and ports. To the great joy of Boeing, President Franklin D. Roosevelt introduced an embargo on the export of helium to the Third Reich. So Zeppelins would once again be filled with hydrogen. The explosion of hydrogen during a landing at the airport in Lakehurst (New Jersey) on 6th May 1937 destroyed the LZ 129 'Hindenburg'. The catastrophe, in which 35 people were burned alive, resounded to the point that potential air travel buffs lost all trust in airships. It wasn't such a great sacrifice for them though, as only a few months after the 'Hindenburg' had burned, Boeing offered them the four-engine B 307 'Stratoliner', the first passenger plane with a pressurized cabin that was able to fly at an altitude of nearly 8000m and had a range of 3800 kilometres. Airlines no longer needed the giant cigars. The army used them for third-rate patrol operations at sea and as barriers attached to cables to make it harder for bombers to attack cities.
That's how the age of the airship came to an end, but maybe not an indefinite end. According to the study concept by Hybrid Air Vehicles, the new generation vessels would be powered by electric engines supplied not only by energy from batteries, but also by energy from solar panels. That would allow the vehicle to embark on flights lasting several days continuously, not to mention neutrality for the natural environment. And that advantage can only gain importance in the very near future.
Translated from the Polish by Mark Ordon
Reprinted with permission of Przekrój. Read the original article.
New ‘bullet plane’ aims to make private flights affordable
Otto Aviation says the hourly cost of flying the new Celera 500L is about six times cheaper than conventional aircraft.
- The unusual shape of Otto Aviation's Celera 500L was designed to maximize laminar flow.
- Laminar flow is the smooth flow of air over an aircraft's wings, and optimizing laminar flow can make aircraft incredibly efficient.
- The plane can hold up to six passengers, and is expected to hit commercial markets around 2025.
An American aviation company claims to have designed an ultra-efficient plane that could someday make the cost of private flights comparable to flying commercial.
Otto Aviation says it's completed 31 successful test flights of its new Celera 500L, a.k.a the "bullet plane." According to the company, the plane features seats for six passengers, a 4,500-nautical-mile range and a top cruise speed of 460 miles per hour. That means it could fly nonstop from New York City to Los Angeles in about the same time as a conventional private aircraft.
But most notable is the low flying cost of $328 per hour. Compare that to the $1,300 to $3,000 hourly cost you and several friends would currently pay to charter a private jet.
How is the price so low?
It's mainly because of the plane's unusual shape. The cylindrical fuselage is especially aerodynamic because it maximizes laminar flow. Laminar flow occurs when air flows smoothly over an aircraft's wings, which reduces drag and boosts fuel efficiency.
Celera 500L
Otto Aviation
Otto says the Celera 500L requires about one-eighth the fuel of a conventional jet.
"The design of the Celera fuselage takes advantage of an optimum length-to-width ratio to maximize laminar flow," Otto Aviation wrote on its website, adding that the design results in a 59-percent reduction in drag compared to similarly sized aircraft. "These benefits will not scale for large jet transports and are therefore well suited for an aircraft like the Celera."
Other specs include:
- Glide range of 125 miles at 30,000 feet, which is roughly three times better than conventional aircraft.
- Fuel efficiency levels that are 30 percent better than FAA and ICAO target emissions standards for aircraft entering service after 2031.
- Liquid-cooled V12 engine, twin 6-cylinder bank, capable of independent operation with mutually independent critical engine sub-systems for each bank.
Celera 500L
Otto Aviation
"We believe the Celera 500L is the biggest thing to happen to both the aviation and travel industries in 50 years," William Otto Sr., the Chairman and Chief Scientist of Otto Aviation, said in a statement. "Beyond using our aircraft for passenger travel, it can also be used for cargo operations and military applications. Since the results from our prototype test flights have been so promising, we're ready to bring the Celera 500L to market."
The company hopes to deliver the Celera 500L to market around 2025, pending FAA certification. If successful, manufacturers like Otto Aviation, Transcend Air, and Airbus could usher in the era of air taxis, where people hail aircraft like they do taxis or Ubers. Paris, for example, was planning to have flying taxis in time for the 2024 Olympic Games, though it's unclear whether the pandemic will affect the project.
Celera 500L
Otto Aviation
As far as how COVID-19 has affected the launch of the bullet plane?
"We didn't anticipate Covid-19," Otto told CNN. "But there are enhanced market opportunities in being able to afford to fly with only those you choose to. Being able to avoid crowded airports and lines is another big benefit. [...] In many cases, individuals and families will be able to charter the Celera 500L at prices comparable to commercial airfares, but with the convenience of private aviation."
New algorithm computes how to find those lost at sea
Researchers devise an effective new predictive tool for maritime first-responders.
- Predicting the locations of objects and people lost at sea is devilishly difficult.
- MIT and other institutions have developed a new algorithm that identifies floating "traps" that can attract floating craft and people.
- The new TRAPS system has just completed a successful first round of testing.
When the first pieces of Malaysian Air Flight 370 finally turned up in July 2015, they were found on Réunion Island off the eastern coast of Africa in the Indian Ocean, thousands of miles from the best-guess location of where the plane went down. Experts weren't especially surprised at the drift, given the complexities of the ocean.
Finding a missing craft or person at sea in a hurry is a nightmare for first responders, and the math involved in tracking survivors — and debris — is anything but simple, given the sea's ever-changing mix of wind, weather, and wave conditions.
Researchers at MIT, the Swiss Federal Institute of Technology (ETH), the Woods Hole Oceanographic Institution (WHOI), and Virginia Tech recently announced the first successful trials of their new "TRAPS" system, a system they hope will provide faster, more accurate insights into the floating locations of missing objects and people by identifying the watery "traps" into which they're likely to be attracted. The team's TRAPS research is published in the journal Nature Communications.
According to Thomas Peacock, professor of mechanical engineering at MIT, "This new tool we've provided can be run on various models to see where these traps are predicted to be, and thus the most likely locations for a stranded vessel or missing person." He adds that, "This method uses data in a way that it hasn't been used before, so it provides first responders with a new perspective."
A Eulerian approach
Image source: MIT
The TRAPS acronym stands for "TRansient Attracting Profiles." It's an algorithm based on a Eulerian mathematical system developed by lead study author Mattia Serra and corresponding author George Haller of ETH Zurich. It's designed to discover hidden attracting fluidic structures in an onrush of changing data.
The traps the researchers seek are regions of water that temporarily converge and pull in objects or people. "The key thing is," says Peacock, "the traps may not have any signature in the ocean current field. If you do this processing for the traps, they might pop up in very different places from where you're seeing the ocean current projecting where you might go. So you have to do this other level of processing to pull out these structures. They're not immediately visible."
The new algorithm crunches through data representing the most reliable available wave-velocity snapshots at the last-known position of the missing item, and rapidly computes the location nearby traps in which a search is likely to be productive. As velocity data is continually updated, so is TRAPS.
Comparing the new Eulerian algorithm with previous Langrangrian predictive methods, Serra says, "We can think of these 'traps' as moving magnets, attracting a set of coins thrown on a table. The Lagrangian trajectories of coins are very uncertain, yet the strongest Eulerian magnets predict the coin positions over short times."
At sea
Image source: MIT
Theory is one thing, and functioning out on the real, maddeningly complex ocean is another. "As with any new theoretical technique, it is important to test how well it works in the real ocean," says Wood Hole's Irina Rypina.
The study authors were pleased — and surprised — at how well TRAPS worked. Haller says, "We were a bit skeptical whether a mathematical theory like this would work out on a ship, in real time. We were all pleasantly surprised to see how well it repeatedly did."
The researchers tested TRAPS off Martha's vineyard in the Atlantic Ocean in 2017 and 2018. WHOI sea-going experts assisted as they attempted to track the trajectories of a range of floating objects — buoys and mannequins among them — set into the water at various locations.
One challenge is that different objects may behave in their own ways in the ocean. "These objects tend to travel differently relative to the ocean because different shapes feel the wind and currents differently," according to Peacock.
"Even so," says Peacock, "the traps are so strongly attracting and robust to uncertainties that they should overcome these differences and pull everything onto them."
In their experiments, the researchers tracked freely floating objects for hours via GPS as a way to verify the TRAPS system's predictions. "With the GPS trackers, we could see where everything was going, in real-time," says Peacock. Watching the objects move via GPS, the researchers, "saw that, in the end, they converged on these [predicted] traps."
Anchors aweigh
The researchers now have sufficient faith in TRAPS that they plan on sharing it soon with the U.S. Coast Guard. Says Peacock:
"People like Coast Guard are constantly running simulations and models of what the ocean currents are doing at any particular time and they're updating them with the best data that inform that model. Using this method, they can have knowledge right now of where the traps currently are, with the data they have available. So if there's an accident in the last hour, they can immediately look and see where the sea traps are. That's important for when there's a limited time window in which they have to respond, in hopes of a successful outcome."
18-ton section of Chinese rocket crash lands following uncontrolled reentry
If you were awaiting screaming death from the skies, you can relax. For now.
- China's Long March 5 rocket core has landed safely in the Atlantic Ocean following an uncontrolled entry.
- Most of the time, returning hardware that doesn't burn up plunges into the ocean or uninhabited areas.
- There have been two larger returnees in the past, though this one was quite big.
Maybe future generations will look back on these early days of space exploration and chuckle at what we had to suffer through. We live in a time when, every now and then, word goes out that some giant chunk of uncontrolled defunct space junk is about to crash down upon us somewhere, so, um, duck? The hope during such moments is that the deadly debris will land in the ocean that covers most of the Earth's surface or in some unpopulated area, and it usually does. Usually.
Anyhow, if you've been anxiously looking up this week — either at the sky or your ceiling in quarantine — waiting for the core section of China's Long March 5 (CZ-5B) rocket to end you, you can breathe a sigh of relief. It landed safely, for humans anyway, in the ocean off the west coast of Mauritania in northwest Africa on May 11.
Long March into the sea
The CZ-5B-Y1 core stage is in a 155 x 366 km orbit, and is expected to reenter around May 11. At 17.8 tonnes, it is the most massive object to make an uncontrolled reentry since the 39-tonne Salyut-7 in 1991, unless you count OV-102 Columbia in 2003.
— Jonathan McDowell (@planet4589) May 7, 2020
Though CZ-5B is one of the largest craft to come down in an uncontrolled reentry, its size is not the only thing that had astronomers like Jonathan McDowell, of the Harvard-Smithsonian Center for Astrophysics, on the edge of their seats. "I've never seen a major reentry pass directly over so many major conurbations!" he tweeted. (A conurbation is an extended urban area.)
While some debris comes down via a controlled landing, that was not the plan for CZ-5B. McDowell tells CNN, "For a large object like this, dense pieces like parts of the rocket engines could survive reentry and crash to Earth." No biggie, he says, since, "Once they reach the lower atmosphere they are traveling relatively slowly, so worst case is they could take out a house."
CZ-5B took off just a week or so ago, on May 5 for just a few days in orbit. Some of its 30-meter-long core stage burned up on reentry, and apparently none of what remained hit anyone, but there are reports of property damage in the Côte d'Ivoire village of N'guinou.
We’ve ducked debris before
A no-doubt radioactive piece of Cosmos 954
Image source: Natural Resources Canada/Wikimedia
At this point, there have been a number of well-publicized spacecraft plummeting down destination-unknown. Probably the scariest was the return of the 4.4-ton Soviet-era spy satellite Cosmos 954. What made its uncontrolled re-entry so frightening is that it was nuclear-powered and threatened to spew radioactive material all over wherever or whomever. The original plan had been to boost it high into a nuclear-safe orbit, but a separation failure doomed the craft to fall back to Earth.
In the end, Cosmos 954 did crash in Northwestern Canada, blowing radioactive debris over a wide area. Canada billed the U.S.S.R $6 million for the cleanup, of which only $3 million was eventually paid.
Probably the first widely publicized uncontrolled return, and one of the two most massive, was of Skylab in 1979. It was another case of a craft coming back earlier than intended, and though NASA couldn't control the 77-ton craft's reentry point, it could control the manner in which it tumbled on down. The nail-biting ended on July 11, 1979, when most of Skylab burned up over the Indian Ocean, though some big pieces survived the descent and landed southeast of Perth, Australia. No one got hurt. The Australian town of Esperance charged NASA $400 for littering. The U.S. also didn't pay up.
Another piece of debris larger than CZ-5B was the Soviet Salyut 7 after nine years in orbit. At the time it came down, it was docked with another spaceship, Cosmos 1686. Salyut 7 weighted in at about 22 tons, as did Cosmos 1686. The connected pair of craft reentered together, burning up and breaking apart over Argentina, with bits raining down on the town of Capitan Bermudez. Amazingly, no one was injured.
One could say we've been pretty lucky so far, though it's hard not to look forward to a time when dying spacecraft can be somehow vaporized out in space where it's safe instead putting those of us down here at absolutely-nothing-you-can-do-about-it risk.
How the Nazis faked part of Hamburg to fool Allied bombers
'Operation Invisibility Cloak' was a waste: Hamburg would soon be firebombed to bits
- In 1941, the Nazis camouflaged an entire lake at the centre of Hamburg.
- A painted tarp was made to look like a bunch of city blocks from above, in the hope of misdirecting RAF bombers.
- But the Brits weren't fooled, and Hamburg would later suffer horrific firebombing.
Operation Invisibility Cloak
Before and after: the Binnenalster and Hamburg's central train station.
Image: Reddit
Now you see it, now you don't: these images, taken by the Royal Air Force in 1941, show how the same part of Hamburg suddenly looked very different from above.
- The most notable difference is the disappearance of the Binnenalster, one of two artificial lakes that mark the center of Hamburg. It has been covered to look like regular city blocks from above.
- Hamburg's Hauptbahnhof, the city's central train station, clearly visible on the top image, has also been camouflaged (although perhaps less effectively).
- A fake bridge, made from wood, wire and thatch, has been slung across the lower part of the Außenalster - the other, larger lake in central Hamburg. By re-creating the actual, hidden Lombardsbrücke, the camouflage operation creates a fake Binnenalster, just north of the real one.
Many attempts at deception
RAF Lancaster bomber over Hamburg during an attack on the night of 30-31 January, 1943.
Image: Imperial War Museum – public domain.
Firstly, because the British bombers targeting Hamburg didn't orient themselves on the Alster lakes. They were guided in by the Elbe, Hamburg's major river.
But most of all, because the Brits caught on quickly to the deception. In fact, the London papers reported on the operation soon after its completion. On July 1941, several published these 'before' and 'after' images.
Operation Tarnkappe was but one of many attempts to deflect the attention of Allied bombers from valuable targets on the ground. Just around Hamburg, the Nazis faked 80 air strips and 32 industrial and traffic installations, while they attempted to cloak real factories, military installations and even Hamburg City Hall.
When the Alster froze in the cold winter of 1940/41, the Nazis planted hundreds of pine trees on the Alster, hoping to trick Allied pilots into thinking they were flying over a forest, instead of the centre of Hamburg.
None of that really made a difference.
Coming within range
As the range of Allied fighter craft expanded, bombing raids deep into Germany became relatively safer for the air crews.
Image: Reddit
As a major industrial center, home to shipyards and harbor for U-boats, the port city of Hamburg was an important target for Allied bombing raids throughout the war.
As British and American airplane technology advanced, Hamburg came within easier range of the Allied bombing effort.
After concentrating on the industrial Ruhrgebiet in western Germany, closer to the UK, Allied Bomber Command eventually started paying its deadly visits to Hamburg.
In July 1943, the Allies unleashed Operation Gomorrah, history's heaviest aerial bombardment yet. It created a huge firestorm that killed more than 42,000 civilians and completely destroyed 21 km2 (8 sq. mi) of the city.
Payback for Coventry
The district of Eilbek, totally wiped out by the firestorm caused by Operation Gomorrah.
Image: Imperial War Museum – public domain.
During the worst night of the attacks, asphalted streets burst into flame, the fiery tornados swept people up into the sky, and many more died of asphyxiation in bomb shelters as the fires consumed all the oxygen in the city above.
A million people fled the city, which saw its production capacity severely handicapped for the rest of the war. After the war, the level of destruction was compared to that of Hiroshima.
Destroying further German cities by firestorm was subsequently called 'hamburgisation' by the Allies; a reply in kind to Joseph Goebbels' cynical invention of the verb 'coventrisieren' to describe the wholesale destruction of a city by aerial bombardment (in reference to the German air raid on Coventry of 14 November 1940).
Hamburg, uncloaked
Central Hamburg today, with the Außenalster and Binnenalster - and even the train station - clearly visible.
Image: Google Earth
Strange Maps #1015
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