During its existence, our planet has collided with asteroids and comets countless times. During her youth, this happened often and often had disastrous consequences. Later, such collisions happened immeasurably less frequently, but from time to time they did take place. Suffice it to recall the 10-kilometer celestial alien that fell to Earth 65 million years ago and put an end to the era of dinosaurs, as well as the cometary nucleus that exploded over Podkamennaya Tunguska on June 30, 1908.
The controversy about threats from space has not subsided for several centuries. At the end of the 17th century, the English astronomer Edmond Halley, the one in whose honor the most famous comet was named, pondered about this danger. In 1694, he shared with his colleagues in the Royal Society of London his fears that the fall of a giant comet could destroy life on Earth. And 130 years later, George Gordon Byron came to the idea that mankind could defend itself from a comet … with the help of steam. Nowadays, more serious methods are proposed - from the use of thermonuclear and kinetic weapons to changing the trajectory of the celestial "aggressor" using traction motors and even sunlight.
Paradoxically, the first detailed space defense projects were carried out not by the military, but by students and graduate students of the Massachusetts Institute of Technology, who worked under the guidance of Professor Paul Sandorff. In the spring of 1967, Sandorff invited students of his course on space technology to find a way to save the Earth from a hypothetical encounter with the asteroid Icarus, which was to approach our planet next year. The introductory one was that Icarus would not slip 6.5 million kilometers from the Earth, as it should have happened and happened in reality, and on June 19, 1968, it would fall into the Atlantic Ocean 3000 km east of Florida. The students had to come up with a plan to prevent this cataclysm - naturally, within the time allowed by nature.
Terrible Icarus
It is now known that Icarus is about 1.5 km across and weighs 2.9 billion tons. In 1967, these data were not yet available, and the parameters of the asteroid were estimated very approximately (in particular, it was believed that its mass was from 380 million to 17 billion tons). The "Rescue Service" estimated that a thermonuclear explosion with a capacity of 1000 megatons of TNT was needed to destroy Icarus. In the absence of hydrogen warheads of such power and giant missiles for their transportation, this option was considered unrealistic. Alternatively, Sandorff's students decided to hit Icarus with six hundred-megaton warheads, which could be produced within a reasonable time. For their delivery, they chose the most powerful of the American space boosters Saturn V, designed for the Apollo program. It was assumedthat in the event of an imminent threat from space, American aerospace corporations will be able to mobilize production resources and build nine such missiles in a year. Three "Saturns" were intended for test launches, the other six - for impact on Icarus.
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Break into pieces
It was planned to intercept the asteroid in two stages. From April 7 to May 17, 1968, four rockets had to go into space at two-week intervals in order to hit Icarus at far distances from Earth - from 32 to 12 million kilometers. The warheads were to be detonated at the command of the onboard radar 30 m from the surface of the asteroid. The calculation was made on the fact that powerful thermonuclear explosions would tear out a gigantic mass of matter from the asteroid's body and throw it into space. With a favorable combination of circumstances, this could change the trajectory of Icarus and force him to miss the Earth. The designers also assumed that the explosions could shatter Icarus into separate fragments, although in the absence of data on its structure, mass and shape, the likelihood of such an outcome was estimated very roughly.
In addition to a direct nuclear strike on an asteroid, other methods of preventing a collision with the Earth are now being considered. True, most of them are effective only "at distant approaches" - only in this case there will be enough time to "move" the asteroid by a distance sufficient for a miss.
Calculations, however, have shown that the success of the first series of launches is by no means guaranteed. Therefore, the Sandorff group proposed to launch two more rockets on June 14 to meet Icarus just a couple of million kilometers from Earth. These explosions were expected to shatter the asteroid into fragments that would cause less damage to the Earth than hitting one large block.
90% or less
The Icarus project was completed almost 45 years ago. Since that time, similar problems have been solved by other teams, and with much more sophisticated tools - up to detailed computer modeling. However, the work of the guys from MIT went down in history as the first study of its kind. Their leader believed that if the project was implemented, the probability of success would be at least 90%. Modern experts are inclined to think that this estimate is significantly overestimated - after all, we are talking about space technologies almost half a century ago. But it’s good that it didn’t have to be tested in practice!
Alexey Levin