[HAYABUSA link] The press conference at 16:00 JST 26th
Fokkowing is translation by Mr. RogueEngineer. Thank you.
Rough English translation of this entry
(press conference part only, no translation for Q and A session):
Here is a report of press conference at 4:00 PM.
People attended: Project Manager Junichiro Kawaguchi, JAXA Executive Director Hajime Inoue, Professor Kuninori Uesugi (Mission Adviser), and the chairman for this conference, Professor Matogawa.
Prof. Kawaguchi: We are giving a summary of the events from last night to today. This is the second attempt of landing, following the first attempt on November 19th. In the first landing attempt, we did a touchdown and Hayabusa stayed on the surface for 30 minutes. In the second landing attempt today, we aimed for the sampling that did not take place in the first attempt. Just after the first landing, Hayabusa entered safe mode and flew far away from Itokawa. It took us a week to get it back to original position.
At around 10:00 PM yesterday, we started descent from the distance of 1km. We used optical navigation to guide Hayabusa first, then we switched to the vertical descent phase at around 6:00 AM. Vertical descent is a maneuver to send Hayabusa to the MUSES-SEA on Itokawa along with the direction of the gravity. Once we enter that phase, there is basically no way to remote control from the ground. At 6:52 AM, we issued a dummy sequence of launching target marker. During the descent we found the target marker from last landing attempt, and we avoided the risk of confusing guidance system with multiple target markers.
Target marker was originally intended to help the horizontal guidance, but from the first landing attempt, we gained experience of guiding Hayabusa without target marker. So we planned a sequence of descent and landing that does not rely on the target marker for today's attempt.
At 6:53 AM, the probe was descending at the rate of 4 to 5cm/s; at 35m from the surface, we stopped laser altitude meter, followed by the start of LDR 2 minutes later. At 7:00 AM, with hovering, attitude adjustment according to the terrain was done. Shortly after that, it switched to beacon operation from telemetry.
At 7:03 to 7:05, the mode of laser range finder was switched from range finding mode to sampler control mode. For today's attempt, we used the parameter to use fewer safeguard to achieve full execution of the sequence. That means Hayabusa will not start ascent without firing the bullets.
At 7:35 AM, we confirmed two bullets (projectiles) were fired.
At 8:35 AM, we switched to the DSN Usuda. Data replay has started at Usuda.
Shortly before 11:00 AM, a trouble, possible leakage, was detected in the thruster system.
Actually we were seeing the sign of this problem during the descent phase, but at that time we switched to the backup system and continued the descent.
When we switched to the main system from the backup system and started the thruster operation, the same problem occured. Due to the attitude change, the probe automatically switched to the safe mode. After that, we controlled the valve to stop the leakage.
We'll use the next three days to get it out of the safe mode. Getting out of the safe mode will be our first priority. After that we'll start downloading of the data.
The amount of leakage of propellant does not seem to hinder the current operation. But it definitely raised the bar of making Hayabusa back to Earth.
Because of the leakage incident, we are not able to see the detail of sampling yet. However, the sequence of the onboarded computer is confirmed to have executed normally. We expect the touchdown attitude was good, but we'll have to wait for the completion of data downloading for definite answer.
Following is translation by Mr. zunda. Thank you very much, Mr. zunda.
Rough English translation of a part of the Q and A session:
Mainichi: Could we explain that Hayabusa fired the bullets and then taken off, at this time?
Kawaguchi: Exactly. Hayabusa is designed to discharge the bullets after detecting lengthwise or traverse transformation of the sampler horn. The data shows that it detected a traverse transformation and discharged the bullets. To sample more, two bullets were fired with an interval of 0.2 seconds. Hayabusa touches down at a speed of 10 cm/sec and the sampler horn shrinks 10 cm. Then, it would wait a second before ascending.
Mainichi: What did you feel when you knew the landing? How was the operation team?
Kawaguchi: We were glad with great joy. Hayabusa controlled itself according to the terrain, touched down, and ascended. The sequence was just what we wanted. All were so happy, including me, of course.
NHK: I may be repeating, but, does the fact that the sequence has been done mean that the sample is acquired?
Kawaguchi: I myself think so. However, we have to collect circumstantial evidence to make it sure. I would like to wait for evidence (in data).
Kyodo: I heard that not much of extra propellant is left. Is there a possibility for another try?
Kawaguchi: I personally feel that an enough quantity of sample has been collected so that it might not be necessary to decent again. I am convinced that the operation team thinks the same. After confirming the discharge of the bullets from the down-loaded data, we will start preparation for a return.
TV Asahi: At this point, has the mission surmounted the difficulties?
Kawaguchi: I have thought that the sample collection is the most difficult part. The homeward journey is basically the same as the outward journey. Reentry to the atmosphere from the interplanetary space is waiting in the last lap. Nevertheless, I fell that we have surmounted 80% of difficulties.
NHK: Everything went without a hitch this time. What was the point for this success?
Kawaguchi: I think that the accuracy in guidance navigation was the key. We aimed to follow the last trajectory. It should not have been exactly the same; however, the last touch down was a very good reference to navigate the vehicle accurately. We have prepared many ingenious tools from two plus one rehearsals and two touch downs. These tools proved fruitful.
Sky Traveler (Gekkan Tenmon): How is the thruster? What happens if you can not restore it?
Kawaguchi: We do not know what happened yet. If it is leaking, it means that the vehicle has flown not only in the smooth space. It would never happen in the space. It might be prove that the thruster has landed on another body. Anyway, we have not confirmed a leakage. Phenomena around the thruster make me think that it is a leakage.
Next from the Tokyo office...
...and there is an another translation by Mr. 5th star manager. Thank you, Mr. 5th star manager.
And following is translation by Mr. nao. Thank you Mr. nao for your effort.
Rough translation (cnt'd). Sorry in advance for possible mistakes and worse quality than former two sophisticated translators.
Asahi: I'd like to make sure. What do you think as a circumstantial evidence to confirm the sampling?
Kawaguchi: For example, vertical standing posture of the sampler horn with respect to the (asteroid) surface. We confirmed it by telemetry data. I'd like to give you the assured facts after carefully investigating the datails.
Nikkei Science: You said that the team has acquired the skill for guidance navigation. I think the disorder of the wheel made the hard task much severer. But you overcame it to acheive the sampling. It means increasing remarkable achivement in acquisition of skills, isn't it?
Kawaguchi:: Exactly. Absence of the wheel causes disturbance by the thruster on the vehicle. On the descending in the rehearsal, we found substantial errors in the position and speed. Based on such experience, we knew completely what to do this time, and we could execute them successfully.
Fuji Sankei Business Eye: Did you confirmed the operation of the pyrotechnics?
Kawaguchi: We'd like to receive data from NASA Madrid tonight, but it will be difficult because Hayabusa is in the safety mode now.
Fuji Sankei Business Eye: Did the leakage stop?
Kawaguchi: We are not sure if it is the leakage, but over-consumption of the propulsion system is stopped.
Fuji Sankei Business Eye: What influence will that have on the return trip?
Kawaguchi: We recognize that it has got harder now. It depends on the operations from now on.
Next from the Sagamihara Office...
Following is translation by Mr. zunda. Thank you for your effort !
Last part of English translation from the Q&A session
... Back to the Sagamihara campus:
Fuji TV: Please excuse us repeating but could you please give kids in front of TV an easily explanation about what we can understand from the mission, which turned out to be successful?
Kawaguchi: On scientific side, we will be able to unveil the history of the solar system. Prof. Fujiwara in the audience is more adequate to explain. However, I am not sure if his explain would be easier or not (laughter).
On the engineering side, we are starting to see an era that vehicles make round trips to other planets. It might be too early as Hayabusa is still to come back.
Fuji TV: How will Japan's space exploration go after this mission?
Kawaguchi: Going to the deep space is not all of space exploration. However, I think this mission is meaningful if this mission stimulates science and engineering. Director Inoue and Prof. Uesugi, would you like to add something? (Both just smiled)
Akahata: Could you tell us about lives in November of you and your team, including hours of sleep?
Kawaguchi: We are exhausted. In November, we made six round trips to Itokawa and this was the first time we did not make emergency diversion (laughter). Furthermore, the thruster is having a trouble after the ascent. It is like experiencing a number of rocket launches at a time.
Weekly Post: Was the target marker dropped last time used for navigation?
Kawaguchi: We planned the flight plan not to use a target marker. However, when it were found, the data recorder was programmed to record it. Actually, we could find the target marker.
Weekly Post: In a sentimental way, could we say that the 880 thousand names guided Hayabusa to Itokawa?
Sky Traveler: How is a quarantine facility for the sample going? How are analysis arrangements set up?
Kawaguchi: Fuel for homeward journey might be a problem. However, I would like to see the quarantine facility set up. We are working on it. Analysis will be done in Japanese and international institutes.
Sky Traveler: Is allocation of the sample changed?
Sankei: How much sample can we acquire with the two bullets?
Kawaguchi: About a few milligrams. As we thought we are sampling regolith, two bullets were shoot. More dust will fly by shooting a bullet to regolith, but the sampler can only trap a little.
Unknown: What kind of conditions were set to abort landing to avoid dangers?
Kawaguchi: We reduced the conditions to three: 1) When the laser altimeter lost its readings, 2) when two of four laser range finder beams lost their readings, and 3) when attitude adjustment according to the terrain goes over 60 degrees. Last time, the obstacle sensor was set to the lowest sensitivity, and still gave a false alarm. Therefore, we ignored the obstacle sensor.
Actually, the obstacle sensor detected something again at this time after adjusting the attitude according to the terrain. It did not abort the sequence.
Matogawa: Director Inoue, would you have comments?
Executive Director Hajime Inoue: We have accomplished unique results within small budgets and limited launch vehicles. I feel sure that we have been doing right thing in front of this big achievement. I wish that the success will provide a tailwind to Japan's space exploration.
Hayabusa is a mission with clear targets. The operation team made step-by-step tests and operations to produce the results. I respect them.
It was also the first time to communicating with the media. There has been a number of failures. However, you helped us. Thank you very much.
Matogawa: Could we have a comment as the mission adviser, Prof. Uesugi?
Uesugi: I thank everyone who showed responses on the network. Prof. Kawaguchi and his staff learned a lot. Control errors were reduced from cm/s in the first rehearsal to mm/s in the last trial and at this time. I would like to acknowledge the improvement in 20 years since the first satellites: Sakigake and Suisei.
There is no other example that a vehicle touched down to and taken off from a body other than a moon. Thank you.
Prof. Matogawa read a statement from JAXA president: omitted here as this would be uploaded to the JAXA www page.
Matogawa: We have been receiving encouragements about the target marker with the 880 thousand names via e-mails and phone. Thank you the media who published warm articles.
Moving to a photo session...
- 【宣伝】4月15日(日曜日)、 『飛べ！「はやぶさ」小惑星探査機60億キロ奇跡の大冒険』朗読会があります。(2012.04.05)