Hayabusa press briefing at 4pm
The major Japanese newspapers carries a headline with the Hayabusa touch down. Some young networker describes the excitements as "I now understand how people got excited about the Apollo 11 in real time..."
After seemingly successful sample return and ascent, Hayabusa experienced some glitch in one of its thrusters. The fuel consumption is higher than nominal. Matsuura's blog covers the press briefing by JAXA/ISAS, and Mr. RogueEngineer's translation covers the good part of Prof. Kawaguchi's briefing.
So here is the rest of the Q&A translation:
Mainichi: Could we take it as the successful firing of the projectile and ascent this time?
Kawaguchi: That's right. The projectile is designed to be engaged when the distortions of the sampler horn either in the longitudinal and lateral directions were detected. According to the data it was engaged by detecting the horizontal distortion. To increase the yield of the sample, we fired the projectile twice, with 0.2 seconds duration.
The landing was performed with the velocity 10 cm per second, and the sampler horn is shrunk by 10 cm. It takes a second to take off since then.
Mainichi: What was your feelings when you realize the touch down, and how was the operation team doing?
Kawaguchi: They were very excited. They excited because the probe touched down as its attitude was aligned to the surface, and took off, all as planned. Of course I was very excited.
NHK: Sorry to be bugging, but are you certain that you got the sample as this operation was performed as planned?
Kawaguchi: I myself regards it as success, but to be certain, we need circumstantial evidences. We would like to wait the data (that supports the evidence).
Kyodo: I understand the remaining propellant is very critical. Would you try another touch down?
Kawaguchi: I myself think we succeeded to get the sample, so I don't think we need another try. I'm sure the operation team regards it as the same way. Upon confirming the successful engagement of the projectile, we will prepare for returning home.
Asahi TV: Would it be fair to say you have cleared the major milestone?
Kawaguchi: We had been thinking the sampling was a major milestone. Returning home is essentially the same as coming here. We still have to perform the reentry maneuver, but I feel we have cleared about 80 % of the milestones.
NHK: We felt it was very smooth this time. What is the point of success?
Kawaguchi: I think it is in the very precise guidance. We brought the spacecraft very near to the point of the last attempt. There was some displacement but we took the last attempt as a very good reference. That would be the reason we could guide the probe precisely. It would be the result of various tools developed by our creative efforts. We accumulated two rehearsals plus one, and two touchdowns. The experience counts.
Gekkan Tenmon: What is the current situation of the thruster? If you fail to overcome the glitch, what would be the consequences?
Kawaguchi: We still don't know what happened. We have a leak means we are not just simply flying in the space. It could not happen if we are in the space. We can state it as that is the consequence of having landed on the different object.
We still not determine it is a leak. We have events that suggest the leak.
Microphone switched to the Tokyo office:
Asahi: I want to make it clear. What are the circumstantial evidences which confirm the sampling?
Kawaguchi: The sampler horn must be perpendicular to the surface, for example. We have confirmed that on the telemetry data. I will explain to you in detail once we get the enough data.
Nikkei Science: You said you accumulated the precise guidance. The challeng had become more challenging because of the (reaction) wheels malfunction. And you have overcome those challenges. Does this mean you achieved more technical scores than nominal?
Kawaguchi: That's right. The probe gets disturbance due to the thrusters because of the lack of the wheels. At the rehearsals there were much more errors in the position and the velocity. We were able to react to them smoothly in the touchdowns because we learned exactly what we had to to.
Fuji Sankei Business Eye: Have you confirmed the engagement of the pyrotechnics?
Kawaguchi: We would like to download the data through Madrid station. But it would be difficult because the probe is now in the safe mode.
Fuji Sankei Business Eye: Has the leak stopped?
Kawaguchi: We are not sure whether it is a leak. The excess in the fuel consumption has stopped.
Fuji Sankei Business Eye: What are the impacts to the returning home?
Kawaguchi: We realize it is very critical. It depends on how we examine the situation.
Microphone has returned to Sagamihara.
Fuji TV: It may be bugging, but could you explain to the children watching the TV about what knowledge you gain on the success of this mission.
Kawaguchi: As for the science we obtain the knowledge of the history of our Solar system. I see Prof. Fujiwara in the guest seats, and he may be better suited. I'm not sure whether he could give us simpler answers. (Laughter)
For the engineering, we are about to be able to carry out the two-way mission to the celestial objects. Sorry to say this. We are still in the middle of the mission.
Fuji TV: Which direction Japanese space development would evolve, based on this success?
Kawaguchi: The deep space exploration is not the whole story. But I regard the mission like this one has a meaning, if they are to stimulate the science and technology. How about you, division director Inoue and Prof. Uesugi? (They just laughed.)
Akahata: What were your and the members' sleeping hours and your lives since November?
Kawaguchi: We are very tired. We performed the descent to Itokawa six times this month, with only this one had the nominal ascent (laughter). Yet we had the thruster glitch. I feel as if we endured the launch of the rocket several times.
Weekly Post: Did you use the target marker for guidance, the one you dropped last time?
Kawaguchi: We have planned the schedule not to use target markers this time. But we chose to keep recording the data if the probe finds it. And indeed it found the marker.
Weekly Post: This might be a bit of sentiment, but would it be appropriate to say, "the names of 880,000 people guided the spacecraft into success"?
Kawaguchi: I accept that.
Gekkan Tenmon: What about the system of quarantine upon the retrieval of the sample? Also how are you going to analyze them?
Kawaguchi: The fuel on return is the question, but we definitely want to have the quarantine built. We are working on it. As for the analysis of the sample, we have established the collaborations with domestic and foreign institutes.
Gekkan Tenmon: Are there any changes to the share of the sample?
Kawaguchi: No changes.
Sankei: How much sample would you get with the two bullets?
Kawaguchi: It would still be about several hundreds milligram. We shot twice as we know we are going to get sample from regolith. Shooting into regolith generates more debris, but the rate of the trap is small.
Unknown: What are the parameters for the risk abort operation this time?
Kawaguchi: We have reduced the traps to three. 1) LIDR lost the altitude, 2) two of the four laser range finders lost the distance measurements and 3) the delta angle of the spacecraft aligning to the surface exceeds 60 degrees. As for the obstacle sensor, we had set it to the lowest gain last time but it was still triggered (for nothing?). So we turned off the abort on the obstacle sensor.
The sensor was triggered again this time, after changing the attitude to the surface. We made a touchdown despite of this sensor.
Prof. Matogawa and the space science research division head Inoue, please make your comments.
Inoue: We have achieved various results with limited budgets and the resource of launch. I'm affirmed with this accomplishment that the way we have chosen was not wrong. I hope this success would lead to pushing the Japanese space development forward.
Hayabusa is a mission with clearly defined objectives. They succeeded by going through the series of tests step by step. I am respectful of the operation team.
We had various glitches on the media relations as we never experience such a mission. We are here today because of your support and understandings. We thank you very much.
Matogawa: Mission advisor Prof. Uesugi, make your comments.
Uesugi: We thank you for the incredible support on the net. Every member inludeing Prof. Kawaguchi have mastered the operation to a great depth. We had errors of a few cm per second in the first rehearsal, but we maintained at a few millimeter per second in this and the last touchdowns. I am grateful that we have come the long way since our first missions Sakigake and Suisei twenty years ago.
It is the great achievement that we have landed and took off to a celestial body other than Moon. Thank you.
Prof. Matogawa reads the acknoledgement by the JAXA general manager Keiji Tachikawa. (It will be posted to the JAXA home page soon.)
The media takes their pictures.
The picture on Matsuura's blog: from left to right: Prof. Matogawa, Division head Inoue, the project manager Kawaguchi, Prof. Uesugi. Photo by Mitsunari Kita.
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