Just project X, this is the development of Hayabusa "ion engine" development and fierce fight record

Among limited budgets, ion engines that have been researched and developed with the approach of improving the performance of engines rather than enlarging rockets. The history of about 20 years is exactly a record of blood, sweat and guts, and there are crystals of new technology and ingenuity to hide the overlapping difficulties that were hidden there.

This is the biggest conference for game developers in Japan "CEDEC 2011""Hayabusa" open space unveiled ion engine with explorer"This is a summary of the lecture by Mr. Kunaka who was in charge of development and operation of Hayabusa microwave discharge type ion engine.


Kuninaka:
Thank you very much for your time today. I am planning to tell you about the operation of Hayabusa, especially the ion engine I have been in charge of.


I have prepared some content, but I do not seem to be able to tell you all, so I would like to introduce some of them. I introduced it under the name of ion engine, but in a wider sense it is technology called electric rocket. I'd like to introduce to the beginning what the electric rocket was like to research and develop for what purpose.


It is a childish manga, but when I have a child here I jump, but I hang on but I feel like I can spin well if I fly well. This is a way of flying called inertial flight.


I say how to fly a satellite is flying, but in reality it is not so correct that I say "I am falling" or "I am doing inertial flight". Most of the artificial satellites that are going around the earth are flying inertia. But let's go further, that is, let's go to the tip while turning the sun, there is a way to go with inertial flight. But there is another way, this is Takeko, but the difference between the former and the latter is that the propeller is attached, so the latter is a power flight that gains power. If I rehash the current story to space technology, this is a rocket. As the rocket obviously injects a jet, it will rise, so this is power flight. A satellite is on the tip of the rocket that powers. An artificial satellite is a vehicle that is given an initial speed by a rocket and then carries out inertial flight. So it means that the satellite is spinning around the earth.


It is a big constraint that there is a technical boundary condition of Japan in this another method of power flight. For example, we have been doing manned missions when it is rice, soy. So they have a huge rocket. However, since Japan is not doing a manned mission, it means that the rocket is not powerful compared to rice. Since there is only a small rocket, I would like to achieve a long distance far flight, wanting to extend the reach of a satellite even further in a small rocket. For that purpose, we have improved the performance of propulsion devices mounted on satellites and have increased reach. Therefore, rather than enlarging the rocket, it is our aim that we have aimed at extending the reach by improving the performance of the engine mounted on the artificial satellite.

"What is a high-performance engine, what is a high-performance engine?" This is a momentum conservation formula. What I would like to mention here is the product of the propellant mass and the propulsion jet speed. This is a remarkable parameter. Since we can not load a lot of fuel, the weight we can put on a satellite is limited, so there is a limit to the total amount of fuel that can be placed there. That's why I want to make a little fuel. The formula will become smaller as the fuel is made a little, but if you speed up the jet instead of a little fuel, this formula will be preserved and the numbers will be the same. To make the jet faster, this is the highlight of the high-performance engine I mentioned earlier.


In the case of chemical rockets, the speed of jet injection is about 3 kg per second, if it is another engine it can be kept up to about 5 kg per second. To make it even faster, you can not reach it without using electric rocket technology. Electric rockets, for exampleIon engineIf you use such technology,30 kg per secondA rocket like that can be made relatively easily. In other words, the chemical rocket is 3 kilometers per second and the electric rocket is 30 kph per second, it is 10 times faster. So it is a conclusion that we need only one tenth of the fuel.


A type of ion engine in an electric rocket creates a jet using static electricity. Even if it says static electricity, it will make plasma. Focusing attention on positively charged particles, it is a system to create a high-speed jet using couple drawn by negative electricity, electrostatic force. I use a substance called xenon for gas. Though it is very frightening with a childish picture, three states in our surroundings, solid state, liquid and gas, that is, as ice gradually warms, ice becomes water, water becomes water vapor, and when it warms further it becomes a plasma I will. Plasma also refers to the state of the fourth substance in the three states in our surroundings.


The plasma is very hot. High temperature is a big obstacle. This is a type of ion engine that the US will advance research. The part to accelerate, which I explained earlier, is the grid. It is said to be like an electrostatic grid, an electro static grid system, but in the part before that, called the discharge chamber, we convert the xenon to the plasma.


One way to make it a plasma is to use an electrode to cause an arc discharge between the electrodes and create a plasma. In other words, to create a plasma electrode is necessary, the electrode must be inserted into the plasma. If a solid electrode is inserted into a high temperature plasma, it will inevitably melt. In particularSputteringAlthough it is such a phenomenon, the electrodes are gradually exhausted. As a matter of course if it goes out of consumption it is not considered as a system, the lifetime will be exhausted. Or I just wish that it will be exhausted as it is, but it is not going to be quite so, you can make a lot of metal powder. When powder accumulates in this discharge chamber, a voltage short occurs, so no voltage is applied. There are also such failure modes.

We started researching in the latter half of the 1980s. Obviously it is later generic compared to rice. Late departure is delayed, so it is inferior. In other words, I think that it is also an opportunity to introduce new technology. So, we aimed to develop an ion engine of a type different from rice straw. It is a very nervous part for life and reliability, but what about the system that does not have such trouble?

I noticed that if the fragile parts (the electrode which is easy to wear out) disappears wonderfully, the elements such as life expectancy, reliability and such worrying are completely gone. It is to become a machine like a dream. So, instead of putting in electrodes, how to make a plasma is to put a microwave into the plasma using radio waves and magnets. I will call it ECR. Let's make a plasma by the method of electron cyclotron resonance (electron cyclotron resonance).


The first thing I made is the Y1 machine which I made in 1989. Of course I could move it to work fine. Although it is in the laboratory, we have succeeded in producing plasma and generating ion jet with speed of 40 km / sec with electrostatic acceleration. However, as far as performance is concerned, it was not a substitute that could be used very much in the universe.

This chart shows the performance of ion source and plasma source. The vertical axis is a parameter representing the power required to operate. I say to the wind that less power is better. The axis of abscissas is a parameter that shows how efficiently the propellant was used. The closer it is to 100%, the better. So in this chart the bottom right will be high performance. The first model I made was very poor performance. This is a place where logs are miso if you look at the vertical axis. It is 100, 1000, 10000, so it was like a performance that is about two orders of magnitude, compared with the level that is usable.


However, as we pursue research and development without encouragement, we have improved the performance significantly in 1990, 1991 and 1992, and when it comes to the μ 10 (Muthen) ion engine that we took on Hayabusa, it got 200 volts , I could reach 80%. When reaching this area it means that compared to the USSO machine, it was able to reach a level that is comparable to the performance. Just to watch it means that it took more than 10 years from 1989 to 2001 and here. To achieve demonstration performance from the idea is that it takes time comparable to 10 years. Because it's technology, I can not do it in a moment.

R & D of systems as well as research and development of ion engines are required. What kind of power supply is used for the engine and what kind of logic will it run with? Development of power supply, development of logic, etc. will be carried out in parallel. In the early 1990s, we collect things around our laboratory, and the ion engine starts working in the laboratory. At that time there was no cost to abundance, so microwave amp ...... This is a very expensive one, but I got very close to the junk shop and gathered junk with feeling like "Is not a good fruit?" There is a memory that I was driving the ion engine.


Though it is nostalgic PC - 98 though it is a nostalgic PC - 98 (lower right of the above picture), I connected the GPIB bus to such a buddy and made something like making software on my own and moving it. From my current computer, I was able to organize machines and make commands similar to hardware, so I remember that it was very interesting and pleasant research in such a sense.

So far it will be part of my research efforts as a researcher and engineer. The other is an organization, the Institute of Space and Astronautical Science that I belong to, or JAXA, but this organization is also deeply thinking about what I would like to do with my organization.


I talked about a satellite a while ago. Please think that there are two in the universe. It is the universe that goes around the earth and the universe that goes around the sun. It was in the first half of the 1970s that Japan jumped out into the universe around the Earth, but it was around 1985 that I debuted in the universe turning around the sun. At that time it was an observation fleet of international Halley's cometsHalley fleet) Was launched from each country, we made a fleet and observed Halley's comet. NASAICE (ice)It is a spacecraft called 390 kg. This is EuropeanGiotto, This is 580 kg. SovietVegaThere are two No. 1 and No. 2, but this is a very large spacecraft of 5 tons. Vega is very involved and I dropped by Venus before dropping to Halley's comet, dropping the upper part, which is a Venus balloon (balloon probe). After stopping by Venus, we are doing very elaborate things to observe towards Halley's comet.


Japan also made a debut in the deep space circling the sun in 1985, but at that time I raised only 140 kilos and it means that there was no ability to raise very slim satellites. As I said at the beginning, it means that the rocket is not powerful compared with the US-Soviet Union, which was a big hindrance. At that time in Japan, 1985 when there was no technical ability to inject only 140 kilometers into deep space. A group called Asteroid sample return small study group is held the same time in 1985. This is a propaganda, but let's try doing in the future that Astronauts (astronauts) will attach to asteroids, pierce the surface with a rock drilling machine, take out the sample and bring it to the earth In the beginning of 1985 I was beginning to think that I should try it in Japan. It is still impossible to do such a difficult thing, but as a propaganda, this means that we were already thinking about going back to asteroids with these satellites.


Let's think about concretely the asteroid sample return mission everyone in 1993. We got a meeting like let's design in 90 days.


This is the document proposed at this time, it is a document issued by the project manager Kawaguchi. This includes technical matters. At the bottom is "Rendezvous, you need a large speed increase for departure, probablyElectric propulsionWe have no choice but to use. In 1993, it was concluded that studies on electric propulsion will be started concretely, such as exploring asteroids and making round-trip exploration.


From the beginning of 1996 the development of the system and the development of the spacecraft will begin. This chart is the difference in development scale between Japan and the United States. The level of US space technology is very high. Again motivation to space development, the dynamics is very different from Japan compared to Japan. Technology has been developed to a very high level. Even if it is called an artificial satellite it is an aggregation of various technologies. For example, it is a propeller, a communication device, a computer, a thermal design, a structural design, a collection of various technologies. We are developing these technologies individually before making artificial satellites. As a result, TRL (Technology Readiness Level, Technology maturity level), technical preparation status is very high. In other words, we say that technologies already close to completion are already lined up on the shelf. For example, once you decide to go to a specific mission, Mercury, go to Jupiter, we will gather the technologies that are already on the shelf and combine it with a bunch of artificial satellites. I am doing this way. Therefore, the satellite development period is very short, and we will assemble the satellite in about three years.


Since Japan has a low TRL, we need to carry out development from satellite system development to component development in parallel. Refining components, researching systems must be done in parallel. Therefore, it means that the period will inevitably become long. For example, component development means "Do you develop ion engines so far?" In my case development expenses are developing and researching at a scale of millions of yen per year at that time.

Next, if you try to make a machine to be mounted on an artificial satellite, you will still need a scale of hundreds of millions of yen a year. This has a two-digit gap. This may also be a bit more comfortable research development if you divide it a couple of times, but at that time it was doing space development with such a scheme. As I mentioned earlier, in order to realize an ion engine of a different type from Yonso, I have made various ideas of them and made it. As a next step, I left the greenhouse called the laboratory, went out to space, I started wanting a great desire to try to move the ion engine.

To do so, we must somehow acquire the cost of this scale and develop the technology. Just whether I can do it. It is the first time for me, so there is nothing for me, whether I can finish it or not. It becomes uneasy as a research institute. When asked, "Can you complete your skills in 5 years?" When you say that "I have not done so, I do not know," I said, "I will not stop using your skills" As it may be told, "I am OK, I can do it." Otherwise we can not proceed to the next step. It is where I think that bluff and bluff are necessary at one time.

It is the durability test of the ion engine that we have to do by spending about that cost. Although I said that it is a long life because I do not use an electrode earlier, it is said that this is qualitatively a long lifetime, it does not prove quantitatively long life. Therefore, it is necessary to prove long life on the ground before launch. The requested lifespan means that it will last 14,000 hours in total operating time in space. We tried to prove 14,000 hours with an endurance time of 20,000 hours. 365 days x 24 hours a year does not reach 9000 hours. It will take two and a half to demonstrate 20,000 hours. We can not but accelerate test, so we have no choice but to prove in real time. So I'm doing the exam for two and a half twice. Actually, we spend time for 5 years only with durability test. This began in April 2000, this red line is the cumulative working time.


We finally reached 18,000 hours at the end of 2002 and completed the second exam. Since the launch is in May of 2003, almost all tests have been carried out to the very last minute of the launch.


How to end this durability test quickly. It is best to drive continuously. BRUNKING FOR 24 HOURS Drive all the time without New Year. And since we can not afford human beings in front of the test equipment, we started doing things like remote monitoring and remote control by connecting the system to the Internet that began to develop at the time. It was in 1996 that I started making this system, and since I started driving in 1997, the Internet environment was not yet full yet, but at that time it was a telephone line, a modem, something troubled I will call you that I've ever heard of it. Next was a pager. An emergency contact comes in at the pager. Pocket bells are gradually disappeared, become mobile phones, then connect with a mobile computer to see how the engine is driving, control from the outside, control on / off, etc., to make such a system There is a memory like I was doing this kind of thing.


This is the situation of driving that was on the web. It is a snapshot of those who seem to feel nostalgic, Netscape. This is a snapshot of the moment when I cleared just 18,000 hours. It says that it is 18,000 hours here. While publishing information on these webs, I was doing durability test.


After all it seems that there was access from quite "NASA" and I was very interested in our activities. As a durability test, it will progress quietly. Especially there was no big problem, but it went smoothly.

Here is the only enjoyment, this is a mission patch .... It is a shot down mark. I will stick these stickers to the vacuum tank every 1000 hours, but if it is 18 to 20, it means that the durability test has been completed. This is the Space Battleship Yamato. Picture of the microwave engine in place of the wave cannon engine. It is a remodeled space battleship Yamato.


This is a sticker when it reaches 9000 hours. This is the shape of the acceleration grid, but before the experiment, this is after 18,000 hours, but the diameter is a bit bigger, but still enough to use this still. I was able to prove sufficient durability.


We are developing various technologies in parallel. Finally it will be finished as a developed asteroid explorer and will be launched. This is our asteroid explorer Hayabusa. Two wing solar cell, this is made up of very high performance solar cell with efficiency of 27% called triple junction cell. This can generate about 2.6 kilowatts of electricity.


This is a parabolic antenna for communication, and the ion engine is mounted on the side. As an ion engine, four ion engines are offered to Hayabusa, and one can run a total of 8 millinewtons at the same time, so it can deliver thrust of 24 millinewtons. One gram of a circle ball has a force of 10 millinewtons pulled by the gravity of the earth. Although it has only a very small force when it is called 24 millinewtons, the universe has no air resistance, so it will take some time but it will accelerate little by little every day, after a year or two years It will be a system that will reach very fast speed.


The Hayabusa probe has a total weight of 500 kilometers. We launched it in 2003, once back to the earth,Swing byWhile doing this, while arriving in 2005 to the asteroid while accelerating with the ion engine all the time. I arrived at the asteroid Itokawa, observed nearby, then landed, taken off, sampled and planned to return to Earth in 2007, but in 2010 I returned home to the earth in relation to various troubles It is a program called.


And finally we will launch it on M - V Rocket No.5 on May 9th, 2003.


It is time for the ion engine to finish. Actually, the rocket phase is just tolerating just because the artificial satellite shop does not do anything. It is finally time to take satellite technology to the Akatsuki when it is put into space. From here it is a fighting place for the ion engine. There are two years of hard quota imposed, and I have little time to stop. This is a voyage for about a month in July of 2004. Red, green and blue represent the fuel injected by each engine.


This is 3 weeks, but every Tuesday was a holiday, we rewritten the command, downlinked the data on this day, then wrote the plan of the plan, and for the remaining 6 days we continued the continuous injection for the last 6 days We will continue to do. I will continue these cycles quietly for two years. And finally I could reach the asteroid Itokawa. This is the orbit diagram, here is the sun, here is the earth. Meros asteroids are here. This black solid line has become the trajectory taken by Hayabusa, stayed by the earth for the first year, staying by the planet on purpose, as close as possible to the sun, and keep the electricity of the sun I will use the ion engine to fully accelerate with full throttle, and will continue to speed up. We bend the accumulated speed with the gravity of the earth and change it towards the direction of the asteroid. It is that we arrived at the transition orbit at last and finally took 2 years and a half to asteroid while injecting with ion engine during this period.

In the meantime, the place closest to the sun is 0.86 astronomical unit. From the farthest sun is 1.7 Astronomical Unit. It means that it has almost reached the other side of Mars, almost to the side of Venus.


This is an operation profile for 2 years. This is May 2003, then September 2005 arrived. Firstly, I am in a place close to the sun, so I have enough electric power, but I am thrusting 24 MPT at the same time of three body driving. As the output of the solar cell decreases as you go far from the sun, we will lower the thrust and reduce the power consumption. The minimum output will go down to 4 millinewtons. Passing through the sun's electromagnetic waves, as I approached the sun, I thrust up and finally arrived at the asteroid. It has become such a profile.


It is said that electric rockets and ion engines, which can vary the thrust, are very rare, but it is at a very high level as a technology. Normally it is not necessary to do throttle driving like this around the earth, but in the case of deep space explorers the distance of the sun is very large, so the electricity changes accordingly Power also changes. In order to effectively convert thrust and change the orbit, we have such a function called throttling. Even though I changed to space operation, when I moved the ion engine for 1000 hours, when I moved 10000 hours, I added a shot down mark like this, I will stick many seals to the window of the control room. At first, I thought about filling in with all this, but since it gets complaints, I decided to cut the number of achievements of the mission by making a break of 100 hours, then 1000 hours, 10000 hours at the beginning. This is a mission patch when it moves at 1000 hours. After all this was Space Battleship Yamato, and the previous ion engine is EPL model, but this has been changed to prototype model. The color of the jet also changed a bit.


Finally stopped the ion engine in August 2005. After that it will approach the asteroid by inertial flight for two weeks. Although it was a point at the beginning, it gradually became bigger at the next day and became bigger at the next day, when the shadow appeared on the surface and I saw "That is a crater", actually it is a big rocky piece It was experienced that it was. Actually, I remember that it was two weeks of bliss for me this past two weeks. In other words, my work is half done. It is half of the work that I had on the ion engine to go out of the earth and arrive at the asteroid. Half of that is over and the asteroids are gradually visible. With technological innovation, we will be able to reach where we could not go. I can see what I could not see. I remember that this was just the moment it was embodied.


Every day was a fun two weeks. This is a movie of photographs of recently arrived and photographed asteroids in a state of death.



As for me, I am very pleased that I do not get tired of seeing that "Why is the surface dull and strangely dressed in a strange looking shape, I wonder if she is doing a strange looking out?", But I am delighted with Cacquia Another engineer lying beside me with a slap in me was bothering to see this picture. It is because I can not find where everywhere lands with lots of rocks. The engineer was carrying the task of having to land off somehow. If you look closely, there is a flat place. It is around this place and this place. Although there is a flat place, I think that you can see that the flat place is becoming a hollow ground. It is difficult to land on the dugout.


We will finally land. If you inadvertently approached to landing on a depression, your opponent is turning, so it will hit like this. The place to land is "Muses Sea", the sea of ​​Muses. I land here, but first I look around far away, when I see the landing point, I will make a quick descent. You can only land in this way. This is a movie that joins the images taken by Hayabusa at the time of landing. This is real rather than CG. This black dot is the shadow of Hayabusa himself. In other words, it is well positioned on the axis of the sun and the asteroid. Muses sea has been visible. I am going into a rapid descent from here.


Here the picture is cut off. What is called is that while approaching while approaching while directing the high gain antenna (high gain antenna) and the parabola antenna towards the earth, when it comes to landing, according to the inclination of the ground surface We will align our posture. Then the direction of the high gain antenna changes and the level of the radio wave falls, communication can not be made. Since the remote control from the ground can not be done after that, the spacecraft thinks by himself, automatic landing and automatic takeoff are performed.


Naturally Hayabusa is two astronomical units ahead of the sun. So, the round-trip delay time of radio waves is 32 minutes, which is an environment where remote control from the ground can not be done very much. This is a snapshot of the closest approach. The shadow of Hayabusa is splendidly photographed. This is a camera attached to the bottom of Hayabusa and took the asteroid's surface and my shadow. The target marker that I dropped when approaching in advance is reflected here.


Successfully we were able to land and take off, but the cause is not quite specified, but fuel leak will occur immediately afterwards. Fuel starts to leak from the local place, the whole spins and loses attitude control, it enters high speed spin. Although I did a calculation to help out variously, it does not work, I will lose communication. And it will be missing. Of course, two missing astronomical units across the sun, 300 million kilometers missing in the morning will not normally restore, but Kawaguchi worked hard and devised various measures without giving up. As I thought, "Fuel leaked here as well, it entered a high-speed spin.The spin axis does not point in the direction of the sun, it becomes a high-speed spin toward the day after tomorrow Therefore, I will lose power as I will not hit, and I will have lost all the functions. "

"Since the spin axis turns around in the inertial space fixation, from this position, if the season changes to this position, there may be timing when the sun's light hits the solar cell, although it does not hurt when luck is bad, but luck is so bad Otherwise, the sun will hit the solar cell someday. " "If so, power will be restored, and if the power recovers, the receiver will be switched on automatically, so continue sending a series of commands that will allow the probe to survive successfully towards that receiver."


I do not know what kind of spin rate it is turning, so I do not know at what timing the antenna faces Earth, so I will send commands at various timings. I will continue sending commands in various combinations so that I can accept commands someday even if I rotate at any rotation speed. "I guess they will probably do such a mission for about a year, but I guess they will not be found any more", but actually I thought, very lucky a month and a half later, on January 23 the beacon radio is re-launched I succeeded in capturing. This is truly a miracle. It can only be said as a miracle.


However, this radio wave is only very faintly coming, I know that radio waves are coming, but I can not retrieve any information. So I thought that this is the ON state of the beacon signal, this is the OFF state, but I will turn on / off on / off work. For example, "Is the temperature of a certain place higher than 0 degrees or not higher? If you are higher, turn on and off the beacon", give a question to do nothing if it is not high, now turn on and off the beacon radio So you can see that the temperature of this place is higher than 0 degree. Then change this to 10 degrees, and if you make the same question and there is no change, you can see the data that it is between 0 degrees and 10 degrees. In this way I did something like communication, accumulated data one by one, confirmed that it was roughly okay state.

However, it is not a state of coming back to the earth very much. We must manage our attitude control somehow. At this point, since all the fuel of the chemical propulsion device for attitude control has leaked out, it is not possible to control the attitude very much. There is no way to control posture at all. I was supposed to do a whole thing here, but well, "Wondering if there is such a thing ..."


Actually it was tilted and mounted with a neutralizer. The thrust itself of the neutralizer is small, but since the torque arm has a considerable distance from the center of gravity, it was imagined that when turning on the gas, the turning power comes out so much. I was able to control posture with this, as I tried, it worked very well and I was able to regain the attitude control with the xenon gas jet. This is 2006. And in 2006 we are doing the calculations for various earth return, and in 2007 I will return to Earth. Ion engine, not the Xenon's cold gas jet of the previous time, I will inject the plasma jet and return to Earth I began to say that.


Originally planned to come back in 2007, I will start orbit conversion targeting 2010 by changing the orbit plan. Two of the three reaction wheels were broken, but while preserving the remaining one carefully, inject the ion engine and control the attitude by slightly changing the direction. Although it is not the original scope, I think that I was able to show that I can do such a thing with an ion engine. And I have been using ion engine for 2007, 2008 and 2009.


However, since this is also a simple machine, I intend to provide a machine with a very long life, but if I use it I will gradually descend. This is a thruster B's appearance in the universe, but it is from 0 to 10,000 hours, about one year and several months. This part is data of specific thrust, but it is decreasing.


It's a machine, so it can not be helped. And in the next 7 months I will return to Earth and the engine will break down. At this time I thought of combining thruster C and thruster B and finally going back to the earth.


On November 4, 2009, a phone call came in the middle of the night and I was told that "the engine is stopped." I thought "I was in trouble", because I had the last train, I came to Sagamihara and thruster B was in a situation where neither Winn nor Sunun moved. At this time, thruster A and thruster B broke down and stopped driving. And since thruster C was also a little degraded in performance, it was a situation that the thruster B of Toroko never moves, it will not reach the earth. I was wondering if everything should be done here, but I was preparing different things in that it would be like this, too.


Thruster A talked about the breakdown, but the cause is that the ion source A is broken. On the other hand, the cause of failure of thruster B was that neutralizer B was broken. I was convinced that Neutralizer A and Ion Source B were sound, so if we can successfully connect these with a bypass circuit, we can drive it as a new rapid engine system. Actually, I kept in advance such a bypass circuit. As I've been thinking for a long time, "I guess you can drive like this if you run this", as my engineer soul "A good opportunity came, the opportunity came to show the technology to the world "About 30% I was thrilled in the sense that I would like to try. 70% thought "I got in trouble". Anyway, I was able to recover thrust in this way and I was able to successfully operate the remaining seven months.

The end is actually a very difficult phase. Since the ion engine is small in thrust, it is an engine used to go to the asteroid about to go back to the earth on about. Precise orbital guidance was not in scope. But finally I have to pinpoint it in the desert of Woomera in Australia. Of course, this is a thing to get used by other countries' understanding, so if you have a dangerous thing just a little, you will not be accepted very much. The place I want to aim is Woomera, but there is nothing special in itself in the desert, but if it falls to Sydney, for example, it can not be accepted very much as the Australian government.


So, although the function of Hayabusa has been lost a little, I have to prove that you can make an orbital guidance precisely with an ion engine. I've probably been okay as I've been doing various operations and working with ion engines. "Because of this kind of thing" Because I have carried out various calculations, I have planned precise orbit guidance with an ion engine and I can successfully execute it.


It is finally a capsule reentry. The spacecraft rushes into the earth at a very fast speed of 2nd space speed, 12km / sec. Since the capsule must be returned to the earth, the surface is covered with a heat resistant shield made of carbon so that the interior is protected even if it generates heat with high speed hitting the atmosphere. Since valuable samples are supposed to be inside, it is designed to protect the interior so as not to be hot. Just because the probe is almost made of aluminum, when it enters the atmosphere it completely melts. In the conventional way of thinking, it was planned to change the trajectory by injecting a chemical propeller after separating the capsule, and planning to change to a trajectory that will not fall on the earth, but truly it is impossible to do such a trick with the ion engine, so we I decided to drop the entire spacecraft to the earth as a decision.


It is time to return to Earth. About 70 JAXA staff including me recovered the capsule locally, but it was a movie I took at that time.



This. This is the mother ship 's shining. It comes in at high speed, so it is not designed to be very tolerable.


It is a pattern that the interior exploded now. The spacecraft itself has melted completely in the atmosphere on the tree end. The bright spots here are capsules. Continuing a very stable flight, decelerating in the atmosphere, deploying a parachute at an altitude of 5000 m, we have achieved landing safely.
Hayabusa Re-entry over Australia - YouTube


Although I was worried, the operation of Hayabusa so far was really a mountain of various malfunctions, errors, and troubles, but the capsule worked very well, the best operation over which we were thinking He did me.


The beacon radio went out as scheduled. I can reliably rely on it and fly with a helicopter, after 1 hour I confirm the capsule which I landed by visual inspection. I am going out to the locality with a helicopter the next day and successfully collecting the capsule. I am here. On the 17th, we are delivering the capsule directly to the Haneda airport from the Woomera airfield with a charter machine. I went on very successfully.


Moreover, although mission patches come out, I basically love to make mission patches, and I make it every time I have it. When I started, there was no mission patch, but in the last time I tried to make a patch, so I confined all the parameters of Hayabusa 's mission in this. We launched from Uchinoura with V5 rocket Unit 5, arrived at the asteroid Itokawa, dropped the target marker, and then dropped Minerva separation robot. Then I used the ion engine to make the round-trip mission to the earth and finally dropped the capsule to the wumer of the earth, which condensed all of the keys in this.


Since there are still mission patches, that project, many people are working together, so I think that it is a good merchandise to adjust the sense of unity of those people. This is not just for Japan, but also for Europe, America, and Australia, so we have to work together, so in order to make an international team and to work together one by one, the team I think that it worked effectively to make a sense of integrity.

So far is the first half, what is the second half what we found out after exploring asteroids.


I am not a scientist but an engineer, so I can not talk much about scientific matters. This is a cover of "Science", it is a picture of an asteroid when you arrive. This is the cover page of this month's issue, August issue of 2011, the photomicrograph of the sample you have decorated the cover page.


This is a picture published by NASA in the United States. NASA is proceeding with exploration boldly. Just a few months ago a probe called Dawn arrived at Asteroid Vesta. They are the pictures taken by Dawn. Vesta is a very big asteroid, but America is a picture that I've been to a big asteroid because I like big things. As a comparison, various asteroids are arranged, in order from the top, Lutetia, Matilda, Ida / Dactil, Eros, Gaspla, various photographs taken by various prospecting machines. Itokawa, which Japan has been doing, is a point ahead of the bottom line. Itokawa, which Japan has been doing, is the point beyond this line. It is not reflected in this size. I have it here, but I do not understand it. Itokawa is such small, maybe I want to say that we went to here.


But, this picture has a very political meaning. Actually, Matilda, Aida, Eros and Gaspla were taken by American explorers. This Lutecia and Stain are the pictures taken by European spacecraft Rosetta. And this is Japan. Then, Eros and America are doing until landing. Japan has fulfilled landings, sample returns and returning to the earth, but in that sense I think that it is also a microcosm that the countries around the world compete and are doing space exploration from the advertisement of technology. Another one, I wanted you to experience the size of Itokawa, I have a photo with you. This is where we are. This is Pacifico Yokohama, this is Sakuragicho, this neighborhood is Yokohama. If you superimpose Itokawa's photos here, it will be this size. It is about 500 m from one end to the other. It is a very big rocky piece from our point, but as we approach the landing of this rock of only 500 m from the wide universe and landing. Then I think that you can understand that it is quite a tough thing to return home once more.


There are also rough places as well as smooth places, as we mentioned at the beginning. It was surprising that such a small asteroid had such duality.


Based on these photographs, various researches are proceeding. One has taken a lot of pictures, so these three pictures are lined up here and this part is overlapping so you can stereoscopically view.


I think that you can see that it is very flat when stereoscopically viewing this. "Why can you develop such a flat terrain?" It may develop into something like space geography.



When I think carefully, it is understood that there is a distribution of gravity even though it is small, and it is understood that sand and stones are flowing down from the mountainous area toward the place with low gravity. This is a profile of gravity.


And it is analyzed that the direction in which gravity is facing and the flowing direction of sand are in agreement when arranging the previous pictures.


Many other sciences are progressing, but again after all, we do sample return and discover particles of asteroid origin from the capsule. Although it is a very small grain of 10 microns to 100 microns, it is specified that it is of asteroid origin, and I think that it may be heard from newspapers and news, but only a part of scientific achievements has been announced recently It is place.


Since I am an engineer, I will introduce this result from a technical point of view. Before we left, we knew the asteroid Itokawa. This is a picture of itokawa taken with a telescope. This black circle surrounded by black circles is Itokawa. From this red line it means that the top is in front of Hayabusa and the bottom is made in Hayabusa. Picture of when rendezvous, photograph when we landed. It is a photomicrograph of particles when sample return was made. This black dot is the particle picked up at the tip of the needle.

This red circle and the green circle are exactly the same if it is at the level of the picture, but I think whether you can understand that the actual size is quite different. Although this has only the resolution of the astronomical unit, since it is a micrograph, it has micron resolution. Since we have material, we are currently analyzing at the molecular and atomic level. I think that it can be said that resolution has reached up to Angstrom. I think that it can safely be said that 22-digit technological innovation has been made from 10 12 to 10 minus 10. This can be reached just because of technological innovation. I think that it is exactly one example that you will see what you could not see.


As for my ion engine's impressions, I am thinking that this is a new concept based on reliability and long life.


On the ground, the durability test of 20000 hours was carried out twice. In space installation, we add 1 extra spare where we can make a round trip with 3 units, and we have built a system with 4 units installed. Furthermore, we adopted an approach to ensure the soundness of the system by using a bypass circuit. It is also equipped with ground handling that is very convenient. Although it was not the original scope of the ion engine, it was able to handle posture control by xenon gas jet, posture control by direction control of plasma jet, precision guidance to the earth.


I think that achieving space operation up to 40,000 hours in this way means that this ion engine was very versatile overall. I think that one can say that engineers on the ground side worked very hard so that we can master it. Once you put satellites into space you can not fix it. It would be nice if someone could go and repair it, but at the moment it's not at that level of technology. As the function gets lost steadily and it degenerates as a mode, the other one we can take is to power up the ground computer and tune it. You can make new software. Although the functions of the spacecraft will degenerate more and more, I believe that it is true that we have backed up the skills of the Earth's computers and engineers who deal with it. I think that I would like to tell such things to you as a stark truth.

About the ion engine, we started research in the latter half of the 80s and 1990s, seven years in research, seven years in system development, seven years in space operation. I have done a total life cycle of over 20 years. All of the development of space technology is done in a very long cycle such as 10 years or 20 years. It has never been a sailing wind for the past 20 years. There was a lot of machinery broke that did not go as I expected. However, I think that I am thankful that I have been able to accomplish these 20 years without losing motivation even in such circumstances. I think this is due to the environment and motivation that my seniors and teachers have given me.


I think there is a way of contributing to various societies. There will be generals who have wide and thin knowledge, and they are very narrow, and instead they are specialists who know everything about it, I guess they are professional stupid, I think that there are people like these. As an aside, Mr. Cliff, my teacher, said, "Become a specialist, specialized stupid, you can be generic afterwards."

One characteristic of Hayabusa's mission is that "various missions are connected to the series". If the M - V 5 rocket does not move properly, the prospecting machine can not operate, and if the ion engine does not move successfully it will not arrive at the asteroid. If we can not land ... ... It will be unavoidable to come back. Not only was Hayabusa able to land and take off, but after that the ion engine moved and finally returned to Earth, the scientific achievements I mentioned earlier were born. In that sense I think that it was a work that connects Tasuki. If the ion engine got stuck here, I could not make up for the latter, so I managed to do my best and made it to arrive at the asteroid. Although there were various things on the way, I managed to bring home the earth with an ion engine somehow.


People with bad mouth say that the mission of Hayabusa is "mission like bubbles". "It is a bad thing that a man who pulled out of Baba and who could not give that Baba to the next person gets a lot of poverty", but we do not think that at all, we always follow the almighty ace of spades all the time I am going to connect the mission to hand over to the people.

Currently we are going to analyze the particles taken from the asteroid. Although it is a trace amount, it does not consume all in this campaign. About 40% will not be contaminated, we will keep it for the future. It is because there is a possibility that a new analyzer will be developed in the future. Then, newly interested people may want to analyze this sample. Rather than analyzing and analyzing this particle with the narrow findings that we have, we want to leave the future to analyze this particle based on the new knowledge that will emerge in the future do.

Because it is such a stone, I do not have anything beautiful, I think scientifically it is a very valuable treasure to take over to the future. There is no way to compare it with treasure of Shosoin Temple or Takamatsuzuka tomb in aesthetic sense, but I think that it is in no way inferior in terms of scientific value, value to be handed over to human beings of the future. Japan has these things. There are techniques to come and have the particles themselves. Divide it into scientists around the world and have them analyze. I hope you understand that you are in such a position.


Next is space exploration. Hayabusa Ⅰ 's heritage is now used to undertake research and development of Hayabusa II. Launched in 2014, arrived in 2017, under the plan to fulfill Earth return in 2020, we are developing at a rapid pace now.


Now we believe that deep space exploration will continue to keep pushing forward with this trend. We introduced about Hayabusa, but Hayabusa II uses Herbushi's Heritage, making it as fast as possible to make a spacecraft at low cost as one scope.


We have already undertaken R & D, and we are considering power sail. Gather a lot of sunlight with a larger solar cell and turn it into electricity. And we are trying to develop a technique to navigate the universe with plenty of electricity. These panel type solar cells are like large size Hayabusa, but we think that such things are already old.


Instead, instead of using a structure, spread the membrane surface by centrifugal force to make a large solar cell so that the membrane surface type solar cell, the membrane surface of dozens of meters, is spread by the centrifugal force. That's why we collect the sun's light, drive the ion engine with the electricity of the sun, and divide it into the deeper universe.


In order to establish these technologies, we are doing various research and development. One is Icarus, launched one year ago. This is a 20 m film surface deployment experiment. Although the solar battery is not tight enough yet, it can not generate large electric power, but we have already done a 20 m class membrane surface deployment experiment as a precursor mission to realize a 50 m class electricity sail eventually. Develop this to 50 m class, collect sunlight with large area, turn it into electricity. And I will embark in the deep space. I would like to open the era of the universe voyage of the 21st century with Japanese technology. Just in the 15th century, people in Europe like the sailing boat technology, jumping out of the Mediterranean world and spreading throughout the Earth, we think that we must also open the age of the universe voyage. This is the future image we are thinking of JAXA.


And I think that Jupiter is aimed at. Jupiter is a very big object in a celestial body. Although it is not scientifically interested, it is a celestial body of great interest in engineering engineering. Using the gravity of Jupiter, if you use the technique called gravity swingby, once reaching Jupiter and accelerating with Jupiter's gravity, the future opens up. In other words, it will be an interchange where Jupiter is stretched in the solar system, or Cape of Peace in the Great Voyage. "As we went around the Cape of Good Hope and reached India from Europe, we mean we can also go around Jupiter to reach the end of the solar system." Pioneering a route to Jupiter with Japanese technology, this has become a big objective task imposed technically.


Finally, we collect a lot of light with a large film surface type solar cell and turn it into electricity. It is electric propulsion with a large amount of electricity, and it divides into the deeper universe with the electric rocket. We will promote research and development efforts towards the goal of opening up such a space voyage age. Hayabusa gathered all the power of technicians and scientists, sticky, faced seven years of space navigation, and returned home to the earth. We believe that small technological innovations will succeed in the world and open up the next future. There is no definite future, the future is said to be what we make. However, without the challenge, I believe that the future will not open.


Currently we are worried about everything about the Akatsuki satellite probe, but we are also operating with the greatest efforts to make a major application fulfillment, so even with regards to this warm cheering I think that I would like to ask. In order to adhere to the trend of promotion of science and technology, I would like to ask for your continued support and cooperation in the future.


I would like to receive your question. Hand softly, please. Please raise your hands.

Questioner 1:
I'm Sony Computer 's Ishihara. Please let me ask you two questions. One point is that everyone thinks technicians want to say "Like this thing" like Mr. Sanada, but it is a circuit that crosses the ion engine and neutralizer of the cross circuit as before. Perhaps it is something that is not essential and costly. I think probably threw away other possibilities, but where did it come from, such as the grounds that it was dared to put it in?

Kuninaka:
As you say, if you use the abundance of cost and mass, you can easily replace the electric circuit in any way with cost, time and expense. However, as a satellite mass is also a big parameter, it is obvious that just doing such a thing does not hold. Since Hayabusa has only 500 kilos, it is truly 10 grams, in units of 100 grams, weight control is being done, if 100 grams are used for cross circuit, there is no inconvenience at all. It is not in an environment that can suggest such things very much. Again it is the use of the head. You can do anything with sufficient mass, cost and time.


Instead, I think that it is the key to think about a circuit configuration that can realize it with only 1 gram. Actually in the case of Hayabusa, we added only one diode, so it's a mass gain of some grams. If so it can be recovered by self-help efforts. So of course it means that we will provide a system that can meet the assumed events after satisfying the technical boundary conditions we have to face. As you are an engineer, I am professional about that field and I think that you are a professional because you have a talent who can provide solutions that satisfy such boundary conditions.

Questioner 1:
Under such circumstances, for example, if there is a technology called A and a technology called B, and both are likely to be able to be implemented at the same cost, can you say that feeling or intuition that it is dare A Is it?

Kuninaka:
I can not quite answer it because it is a very general and general question, but I think none and none of A and B are totally equal. Think about where you should pay attention and what you have to pay attention to depending on the application. I think that it is not the same as being tough enough to choose.

Questioner 1:
After all it is the first step to grasp such things such as the situations where you are situated, and there is technology on top of that. Thank you very much.

Kuninaka:
Other, is there any? here you go.

Questioner 2:
Let me question about education. Following this, how many people have you grown up to be able to do the same thing in the next project through this Hayabusa project, for example? Or have you tried to develop human resources within the project?

Kuninaka:
it's difficult. Although I think that there are various kinds of grades from the education of graduate students and the education of professional engineers even for education, I think that there are various kinds of grades as a graduate student from the viewpoint of graduate student education about Hayabusa We have established and are participating directly in operation. So I guess how much they motivated me. In the technical aspect, each research department is refining technology. For example, I am the electric power department. Then there is such a department, such as the orbit planning department, always in such hierarchy, then in the educational system, education of graduate students and education of engineers and then research and development of new technology are done in parallel.

Specifically, some people say it is a bit difficult, but Hayabusa II has done a lot of refreshing activities with young people. Since we have been doing this Hayabusa I in the past ten years scale, people of the same age as me at that time are now working on Hayabusa Ⅱ, so in this sense proper human resource development I am watching it as if I have come up.

Questioner 2:
Thank you very much.