Impressions from the space seat from the Israeli Air Salon - Aerospace Conference 2011 at the Nation Buildings in Jerusalem, November 30
In this article we bring impressions from the space seat from the Israeli Air Salon - Aerospace Conference 2011 in the Nation Buildings in Jerusalem, November 30.
The conference, which opened with congratulatory remarks by Minister Matan Vilnai and senior industry and military representatives, was quite impressive. Hundreds of participants were able to review a comprehensive supplier exhibition where dozens of Israeli and foreign companies presented their wares in the space and aviation field, and sit in a number of professional seats in the fields of technology and defense. Personally, I got to sit in the space seat, which was fascinating.
At the Space Session, Meir Chen, director of development of future issues at Bat Halal (TAA), told about a space constellation for maritime monitoring. Today, monitoring of civilian vessels is done using a VHF transmitter called AIS (Automatic Identification System). According to the order of the International Maritime Organization, (International Maritime Organization - IMO) every ship of 300 ton-meters and more must carry such a transmitter (although smaller ships are also sometimes required to carry one). Signal monitoring is done in the MMG system (geographical information system, such as Google Earth). With the help of the system, it is possible to know the location of any vessel carrying a transmitter, and receive from the system an information card that includes its picture, details about its cargo, its flag, etc.
However, the number of vessels moving at sea will only increase over the years. In the European region, for example, the expectation for 2029 is 100,000 vessels on the coasts and rivers of the continent. Monitoring such a huge amount, in order to ensure their safety, security, proper utilization and documentation of pollution they may produce, will be a huge challenge for the stakeholders (coastal states, maritime authorities, shipping companies, etc.). It is enough to imagine a case of pollution in one of the cruise lines. Without adequate monitoring, we will not be able to know who the polluting vessel is, what substance is emitted into the water, and who will be responsible for and pay for the restoration of the environment. Other reasons that force constant monitoring are illegal fishing that burdens the local environment and economy, such as threats from pirates (though less so on European coasts, at this point).
Recently, the European Space Agency ESA issued a call for commercial companies to cooperate under the name SAT/AIS (Satellite Automatic Identification System). That is, monitoring from space of those radio transmitters. Several companies are already operating in the field, such as ExactEarth and the Canadian SpaceQuest Canada, which collaborate and build nanosatellites. However, the aviation industry also has the commercial capacity to respond to future ESA needs. The Israeli Tuskar and Offset 3000 satellites move at low altitudes and will be able to answer the need for monitoring ships on which no AIS transmitter is installed. Additional Israeli satellites will be able to provide coverage of the North Atlantic Ocean and hundreds of miles into the sea around the coast of Africa, including the pirate-infested Horn of Africa. Of course, these and other satellites will be able to operate jointly (as a constellation) and thus provide extensive coverage in different resolutions.
Ilan Porat, the head of the space department at Alup and Elbit told about the Jupiter optical system, which has the high resolution and wide field, which enables images and measurements even in difficult visibility conditions. Black and white photographic resolution is half a meter from an altitude of 600 km. The width of the field at the same height is 15 km, and the image consists of 30 thousand pixels (size of each pixel: 13 microns). The data transfer rate is 5.6 GB per second, not trivial at all. The camera allows binning, that is, uniting pixels according to need, which reduces the volume of information for faster transfer of images that do not need high resolution. This process has so far been done off-camera on an external computer that required electricity, or on the ground. Despite these capabilities, the humble Jupiter system weighs less than a hundred kilos, and consumes less than 200 watts.
A technological innovation found in the system's detectors themselves reduces the need to offset the movement of the satellite (movement aimed at photographing a target from two different angles). Since seven offsets reduce the flux of solar radiation reaching the solar cells (or stop completely), this has a huge advantage. There are 5200 elements on a single detector, and one detector is actually made of two identical detectors. Each detector has its own power and electronics system. Admittedly, this duplication results in a double consumption of electricity.
But there is a huge advantage here: if we photograph a building from space, it is possible that its shield will fall on a parking lot where important information is hidden. With normal cameras we can only photograph the lighted building and an object of interest standing in the parking lot will be hidden from our view. Alternatively, in order to know what is in the parking lot we will have to overexpose the image, catch the hidden but "burn" the building. So, in order to get all the information, we will have to shoot twice - once with normal exposure, and once with overexposure. And what if the next photo opportunity comes only on the next lap? Or even a few days later? It is possible that we will go back for another shot and the target will already roll out of place or be blurred. In the case of a double detector it is possible to take two pictures with a different white balance, as if we were taking pictures with two separate cameras. That is, at the same time we will get the illuminated building in one image, and the shaded parking lot in another image.
Tal Inbar, head of the Center for Space Research and UAVs at the Fisher Space Research Institute, presented a familiar problem: during a one-off event (earthquake, tsunami) or continuous (fire, flood), monitoring from space can immediately assist in estimating damages and managing rescue efforts, especially where Every hour counts. However, space infrastructures are often not available at such a time resolution. why? First of all, because the possibility of providing different capabilities from spacecraft already in orbit is very limited (in general, satellites are launched with specific monitoring and movement capabilities that cannot be changed from Earth). In addition, the ability to assemble a satellite on demand and launch it within hours does exist in the hands of NASA, but it has not permeated the rest of the world (and it has not been practiced in the US either, except for a single experiment). Therefore, when the need arises, it sometimes takes several hours or even days to receive important input from a military or civilian satellite that is already in orbit. As a solution, Inbar presented the Responsive Space concept: First, satellites will be better utilized so that they can be freed from their mission to monitor one important event or another. Secondly, warehouses of satellites and satellite parts will be built that will be ready for shipment on demand. One of the main problems here is the standardization of components. We'll explain: how many times have you forgotten your cell phone charger and had to refuse friends' offers because the charger they have doesn't fit your device? This is the problem of standardization, which according to Amber may soon disappear in the field of space. Third, there is a need to develop available, simple and reliable launch structures that will require minimal maintenance before and after launch. This is where the Japanese Space Agency is making a difference, with the development of the M-5 launcher. The twist at the end of Inbar's words is the fact that such an array can be completely civilian (Civilian Responsive Space - CRS), and in the possession of countries that understand the advantage of receiving information from space. Israel is among them.
Midd Farinta, from the Israeli specialist company and former "Amos" satellite man, talked about the problem of space pollution by man. It turns out that tens of thousands of objects larger than 10 cm orbit the Earth, and of these only a few hundred are active satellites that are indeed supposed to be there. The rest are inactive satellites, parts of unused launchers and remnants of satellite collisions. In principle, some of the space debris is monitored, but at a very low level (none of the collisions that happened in space were predicted in advance). In addition, a serious problem emerged when countries began to try ASAT (Anti-Satellite) weapons. These are missiles for all intents and purposes, whose purpose is single: to destroy a satellite in orbit by detonating it. Such an event may create many fragments, most of which will remain in orbit for many years. A serious problem arose when China carried out a brutal experiment in which a Chinese satellite engaged in monitoring the weather was destroyed by a sea-to-space missile launched by the military. This unannounced experiment resulted in the formation of many fragments, most of which will remain with us for many years to come. The space station had to change its course several times in order to avoid crises created during the experiment. Also in 1993, 1998, and 2003 there were collision events associated with the impact of fragments on active satellites. One of the highlights of the events is the collision between an Iridium satellite and a Russian Cosmos satellite. In addition, in January of this year, the space station team evacuated to MMD with 27 minutes' notice due to a fragment of space debris that passed them at a distance of only 250 meters - here it was clearly a great luck. According to Mr. Farinta, the problem is similar to the problem of ocean pollution. If it was once thought that the sea would tolerate everything, such as sewage discharge, marine pollution and waste, then today we all pay the price. So will it be in space. And why wait? The possible consequences of collisions in space are many, starting from the reduction of communication frequencies in space following the loss or damage of important communication satellites to the total halt of launches. If we examine the implications for reducing space communication frequencies, for example, it is an unpleasant story: on these frequencies, television signals, telephony, and even credit card transactions are carried. Reducing the bandwidth for this communication will result in pricing per bit of communication that passes through it, and the cost will, obviously, be passed on to us consumers. And let's not mention the danger of debris falling from space, as happened recently with the American URAS and German ROSAT satellites, which in turn fell to the ground in uncontrolled falls. According to Farinta, controlled entry satellites can be designed so that they burn up completely in the atmosphere, and it is mandatory to do so.
Dr. Nissim Yehezkel, Head of Engineering Administration at the Mabat Halal plant, told how cost-effectiveness and performance sometimes do not change for the better when the size of the satellite is reduced.
