The initial results from the crash operation of a projectile launched by the Deep Impact spacecraft with the comet Temple-1 reinforce previous knowledge about comets and also provide new information
This image was taken by the Impactor - the spacecraft that collided with Comet Temple-1 about five minutes before the collision. There are also pictures taken right near the comet a few seconds before the collision. The BBC reports that the plume of material that came out of the comet due to the collision was bigger and brighter than what NASA had seen. And therefore it is possible that the spacecraft missed the opportunity to observe the crater caused by the collision, due to the large plume created by the ejected material. Viewing the crater was supposed to provide scientists with information about the internal structure of the comet, but the team is convinced that indirect methods for estimating the dimensions of the crater will help them understand the nature of the crater. All over the world, professional and amateur astronomers followed comet Temple-1 before, during (for a few the comet shone in their night sky when it happened) and of course after the crash. About three days after the operation, on 7/7 the Astronomical Club of Tel Aviv University held a conference which was opened by researcher Dina Prielnik who gave a general background of what comets are, and talked about the surprising connection between the materials coming out of novae - exploded stars and the components of the comet. David Polishook from the Department of Astronomy at Tel Aviv University said: "We were part of the international effort because we were registered as an official observatory and therefore we were also updated on all developments. Each night we could only watch Comet Temple for two and a half hours from dark until it set. We used the new telescope at the Wise Observatory in Mitzpe Ramon. Although it is smaller than the old telescope, its mirror diameter is only 18 inches and it has no filters, but on the other hand it works by remote control and changes its direction automatically according to a pre-planned observation plan. Our photographs show that the comet's tail is very thin. You can see through it stars that are behind it. We uploaded photos to the website while observing. We wanted to see if a picture taken on Sunday evening, before the collision and then on Monday - about 12 hours after the collision, and see if there were any differences and we found no differences in brightness, although some saw differences the next day. Apparently after 12 hours the dust subsided, or the clouds and dust lowered the brightness. The reports from the project were compiled by Gal Sharid, a doctoral student whose research specializes in comets: "First we ask ourselves why do we study comets? As Dina said, comets are archeological remains, frozen remains from the formation period of the solar system, they provide clues to the physics and chemistry of the solar nebula, preservation of the interstellar matter and they also contain dust and water which are the bases of life. Also they are just beautiful. "The comets brought water to Earth, perhaps as much as two-thirds of the water on Earth. They brought organic materials - carbon and hydrogen compounds. Comets are responsible for the heavy bombardment of the inner planets - also seen in photographs of planets and moons. We have partial knowledge of the chemistry and physics of the halo and tail but know next to nothing about its internal composition. We do not know about their development and the processes of "disappearance" - the extraction of the gases, whether they are sealed. We do not know about the structure and composition of the nemesis, about the chemical abundance in the halo and nucleus, nor do we know the basic material properties of the nucleus (mass density, strength, heat conduction, etc.) The main goal of the Deep Impact mission was to understand the difference between the interior of the comet and the surface, to determine the properties basic materials; Exploration of "primary" materials below the surface. Until now, missions such as Deep Space 1, Giotto, and Stardust were dedicated to comets, which only photographed the face of the comet that each of them studied. The secondary goals of the operation were to understand the processes of disappearance and the physics of creating craters (a projectile hits some kind of terrain, what happens). The Deep Impact mission is part of a NASA concept called the Discovery Program. According to this plan, NASA will not be the main cause, the main feeder of space missions. NASA wants to produce an abundance of cheap, short, fast space missions. Instead of NASA starting to issue tenders for the construction of a spacecraft, program and more. NASA receives a ready-made project from a person and he must not exceed the budget (300 million) and time (3 years). The famous missions within this project were Mars Pathfinder, Lunar Prospector, Stardust, Genesis - a mission that collected solar particles, sent them in a capsule to Earth and managed to save most of them. Contour - that a month after the launch, contact with her was lost. DAWN to attack Vesta and Ceres and Kepler to help us discover Earth-sized planets outside the solar system. Temple, the man who discovered the comet was a very successful astronomer and discovered many comets in the observatory near Florence that he managed from 1782 until his death. Temple-1 is the first comet he discovered. Comets are divided into three types - Yakutki - a very long time 17 thousand years, Halli which belongs to its own type. and Temple-1 of the righteous comet type (meaning their orbit is inside the orbit of Jupiter). Temple-1's cycle time is 5.5 years, its closest distance to the Sun is 1.5 AU, it rotates around its axis for almost 42 hours, and the effective radius is about 3 kilometers. The comet was observed by the Hubble, Spitzer space telescopes. Its activity is also watched when it approaches the sun - the same jets of matter that are emitted from active areas on the comet's surface. Comet Temple-1 actually rotates around more than one axis. The Deep Impact mission was launched on January 12, 2005. The planned time was about six months. She performed orbit maneuvers, released the impactor, performed another orbit change to position herself in front of the comet. The impactor also performs orbital maneuvers in order to hit a certain point on the comet. At 852 Israel time, Monday morning, 13 minutes of observation by the flying spacecraft, after which it entered a protective mode so that the dust particles thrown from the comet would not damage the delicate instruments. After passing for half an hour at a distance of nearly 500 km from Gal'in, she turned back and continued to photograph the results of the meeting. This is a very simple task. The beauty of it is that it is relatively simple and easy. In total, there are three devices on the spacecraft - a large camera (actually a large telescope), a smaller camera and the impactor - which is not a device the size of a washing machine that crashes into a comet with complete unawareness, but is a functioning spacecraft with navigation software, its own camera, thrusters. The entire platform fits within 3 meters of the head contents of the Delta 2 spacecraft. As for the mother spacecraft, it weighs about 650 kg and receives power from solar cells as well as a small battery to maintain the activity during protection and during transit. thrust engines. It's all about the size of a beetle. The impactor - the impact spacecraft - has a mass of 370 kg and an impact speed of 36 km/h. Operates as an independent spaceship only from the moment of disconnection. Starting 24 hours before the impact, basically 2 independent spacecraft were operating. She also has weaker thrust engines. The impactor consists of copper coins stacked one on top of the other, something like 100 kg of copper (45 thousand one-cent coins). At the front of the impactor we see a target sensor - a camera designed to bring the target spacecraft to the most optimal point of impact. The devices - MRI: medium resolution camera. It is a telescope with a diameter of 12 centimeters capable of photographing with a resolution of 10 meters per pixel from a distance of 700 kilometers. A filter operating in the visible range is mounted on it. On its way, the spacecraft photographed the moon for camera calibration purposes. The purpose of the camera is to provide viewing results but also to enable better navigation and maneuvering of the spacecraft. The ITS (impactor target sensor) device is the same as an MRI, only without the visible field filters. The serious and important device on the flying spacecraft is the HRI - a high resolution camera. A slightly bad picture of Jupiter taken on February 6. worried the researchers who determined that the malfunction was due to the accumulation of moisture. They turned on the radiator and fixed it. The diameter of the telescope's mirror 30 centimeters makes it one of the most powerful ever launched for a mission in the solar system. The device provides a separation of 2 meters per pixel from a distance of 700 kilometers. It contains a spectrometer with infrared wavelengths between 1.05 and 4.8 microns. It is an important field because we see reflected light, emitted light, absorption characteristics of ice, silicates and organic compounds, as well as of stimulating gases that can be emitted as a result of the emission of gases from the core. One of the only official results published - towards the end of June, the device photographed Temple-1 and you can see lines of water, carbon monoxide and hydrocarbons. This is similar to Halley's infrared spectra, meaning that the guess about the composition of comets was confirmed in two independent space spectra. As mentioned, 60 observers around the planet watched this mission, and they covered almost the entire world. It was an impressive collaboration. In addition to the professional observers, there were also amateurs and NASA cooperated with them in the widest and most impressive way to date. The program of observations by small observatories and amateur astronomers began 20 years ago but reached its peak with the Deep Impact activity. We of course have observers in space and everyone showed up for the day of the order to observe one tiny object: Spitzer in the red Ipanera field, Hubble in the visible field, Chandra in the X field and Rosetta. The Hubble Space Telescope photographed a nuclear explosion on June 14. Chandra took a great picture. We also see Hubble's observational analysis of another eruption. On April 25, 2005, the first picture showing Temple-1 was taken and it was taken in order to calibrate the spacecraft's navigational means. Along the way, three eruptions of the comet observed from Earth were recorded on June 14, June 22 and July 2. There has never been a continuous observation of comets, so it was a theoretical guess reinforced by random observations. These are natural eruptions. Nothing hurt him. 24 hours before the impactor undocked, there was tension at JPL until a Deep Impact photograph of the prodigal son arrived. An hour and a half before the impact, the impactor started the impact maneuvers. The spacecraft is completely independent and determines by itself the best point to hit. We are looking for the brightest point on the comet, we also consider shape data, aiming not to hit exactly the brightest point. Want to hit a point that is not completely dark but also interesting. Bright components indicate to us ice through which it is possible to penetrate. At 20:300 Israel time the collision The last photo published by NASA taken by the impactor rushing to its death was taken XNUMX seconds before the impact from a distance of XNUMX meters from the comet and in it you can see many landscape formations, including craters. What is the terrain route, what are the bright and smooth areas? What can we learn from the field route? There is also an unpublished photo, which was taken 3 seconds before the collision from a height of 30 meters above the face of the comet. In the control room at JPL, these results have been waiting for seven and a half minutes because the impact occurred at 0.9 astronomical units. Then they see the image of the eruption taken from the spaceship that flew by. NASA TV broadcast the event live. In the control room, you can see a constantly updating image, for a moment it disappears and we were afraid that something had happened to the camera. Indeed, these are the Independence Day fireworks, the 4th of July. The impactor has finished his work and now the work of analyzing the findings begins. The Hubble takes a sequence of pictures an hour and a half after the impact the Hubble takes a picture of a very large fan of dust, it is different in its form from the natural jets. It says something about the speed of the dust particles and their sizes. Newton's X-ray telescope also took pictures but no one talks about them. Probably no successful results. There is a clarification pattern with two peaks - one before the explosion and one after it, but no one has yet analyzed the results. Deep Impact itself looks back, 50 minutes after the impact, the high-resolution camera captures a dust fan. A conical shape that can also teach us about the material itself and its interaction with the material that hit it. 67 seconds after the impact what can be concluded from the impact data and the analysis of the emission from the crater? This is an open question. At the press conference we saw in the photographs of the impact, immediately after the impact a beam came out and then there was another very large eruption. This probably reinforces models of the core structure in which the top layer is soft made of porous ice with a layer of different composition underneath. Pete Schultz, a member of the scientific team that was in charge of the crater experiments. When asked by a journalist who won PULL. We don't know who won but we know for sure who lost. Mike O'Hearn, the project's principal investigator who spent decades studying comets and years planning the mission. - Did the mission meet your expectations of it, he answered: "There are so many things we don't know about comets, I estimate that it will take a few more years until the results are anchored in insight and clear scientific models. As for the same news on the BBC that we started with, according to which due to all the maneuvers and entering the defense of the spacecraft and due to the much more than expected material emitted from the crater, they actually did not photograph the crater. Reid answered: "The exhaustion as a clear and easy-to-view image, I don't believe that they would have photographed it in any way because after the impact there is an emission of dust. The dust reflects light and some of it also emits radiation because it heats up.
