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Sanjay LimayeDecember 7, 2015

Live from Sagamihara: Akatsuki Orbit Insertion Success!

Sanjay Limaye continues his first-hand account of the Akatsuki orbit insertion, begun here.

December 7, 2015

3:50 am, outside ISAS

Akatsuki is speeding towards Venus at 3.28 km/sec, only 72,000 km away. The sky is partly cloudy so Venus should be visible. Time to go to find the telescopes being set up at ISAS for the public to see Venus.

More than 50 people showed up from as far away as Scuba as well as Sagamihara for the public viewing through telescopes set up in the ISAS compounds. Now the viewing is at the nearby museum which has a telescope. Quite a few people at the viewing session had seen my previous blog entry posted here! A few came up to me and inquired if I was writing and thanked me.

There is a live commentary going on in the Project area and engineers are checking off milestones. Akatsuki is moving at 4 km/sec and only 40,000 km from Venus....

8:00 am, inside ISAS

Takeshi Imamura walks into the work room for breakfast. He is guarded, cautiously optimistic and confident.

Akatsuki is moving at 6.34 km/sec, about 11,100 km away only.

Chikako Hirose, a young female engineer, leads the trajectory design. She will know from the Doppler shift how the burn went. Delta-V expected is ~ 100 m/s. Canberra, Usuda and another JAXA dish near Kagoshima are tracking.

Chikako Hirose (ISAS) who worked on the Akatsuki trajectory, pleased that her work paid off.

JAXA

Chikako Hirose (ISAS) who worked on the Akatsuki trajectory, pleased that her work paid off.

8:13 am. We see the Usuda station signal in the control room

8:30 am. Akatsuki is behind the planet so we cannot see the signal from the high-gain antenna.

8:33 am. Received confirmation of the first command of the burn sequence has been executed. One-way light time is about 8.5 minutes.

Akatsuki Control Room during the orbit insertion process.

JAXA

Akatsuki Control Room during the orbit insertion process.

8:37 am. Some of the team are peering through the glass window into the control room

8:38 am. One of the staff has made special labels for soy milk boxes - a pun on the Japanese word for orbit insertion. "Tounyu" is the name of soy milk and the orbit insertion term.

8:51 am. Maneuver has started.

9:01 am. Graph of expected Doppler shift is on the right screen. So far actual Doppler matches the maximum!

9:19 am. Takehiko tells me now that it has reached 90%. Akatsuki is in orbit it would seem!

9:21 pm. Thrust now is higher than 100%! Could be slight misalignment of thrust value than assumed?

9:23 am. Every one clapping! Masato declared we are in orbit!!

Akatsuki is in orbit!

JAXA

Akatsuki is in orbit!
Masato Nakamura declares Akatsuki is in orbit around Venus.

JAXA

Masato Nakamura declares Akatsuki is in orbit around Venus.

Compared to the exuberance at similar NASA mission events, it feels quite subdued! The Akatsuki team achieved something that no mission has done before – put a spacecraft into orbit around a planet using only the attitude control thrusters. An event that one could not even conceive or propose!

Takeshi Imamura comes out of the control room into the work/break room and looks greatly relieved. He still has work to do. In fact now that the spacecraft is in orbit, the attitude of the spacecraft has to be continuously updated. The commands will be generated manually and uploaded until the orbit is known better.

For the insertion burn, the high-gain antenna could not be used because the orientation of the spacecraft required to be such as to produce thrust counter to the direction of motion to reduce the speed. The medium-gain antenna was receiving signal from the ground station and transponding it back to provide the two-way Doppler, since the entire maneuver was visible from Earth. However, the signal received from the medium-gain antenna is quite weak. When the telemetry data from Akatsuki started to be received after the 8 minute 20 second one-way light time delay, a graph was flashed on the right screen showing the expected cumulative velocity change for maximum thrust from the four rockets and several other curves showing values for different fractions of the maximum thrust. We are all watching the data trickle in – the real delta-V points were falling on the maximum thrust curve! Exciting!! Trajectory calculations were done elsewhere using the data from Usuda (JAXA) and Canberra (NASA/JPL DSN). At one moment there is a break in the graph, a gasp is heard, but the graph resumes again as the data flow continues. The Usuda DSN had switched to a different orbit model, which caused a few seconds break.

12:00 PM JST Press Briefing

JAXA's press release on the successful arrival at Venus is posted on their website.

The conference hall at ISAS is full of media persons. Nakamura arrives and an ISAS Press Officer asks him some questions, a after a few words begins taking questions from the media. No handlers for the briefing, no senior officials from ISAS or JAXA – is the Program Manager’s show. I notice only a few persons from the Akatsuki team. Very different from a typical NASA briefing.

Masato is smiling answering questions – it is all in Japanese, so I cannot understand anything, except guess at the question and the answer from Nakamura when he uses the spacecraft model to illustrate. At one point there was laughter - Prof. Nakamura said that unfortunately he cannot give a refund for the express ticket to Venus, but glad that he took us to Venus.

In half an hour the briefing is over.

Venus in the ultraviolet from Akatsuki, December 1, 2015

JAXA

Venus in the ultraviolet from Akatsuki, December 1, 2015
UV (365 nm) image from Akatsuki taken on when Akatsuki was 1.1 million km away from Venus, five days before orbit insertion.
Venus in the infrared from Akatsuki, December 1, 2015

JAXA

Venus in the infrared from Akatsuki, December 1, 2015
Venus at 900 nm wavelength imaged from the IR1 camera when Akatsuki was 1.1 million kilometers away from Venus, five days before orbit insertion.


Following are translations of tweets from the press briefing by space journalist Shinya Torishima (@Kosmograd_info), translated by @5thstar.

Akatsuki PM Nakamura: We completed the ops of Akatsuki entering into the Venus orbit. Confirmed it went smoothly. https://t.co/7Eg4ucCK07

— Fifth Star (@5thstar) December 7, 2015

Direction and the duration of the burn was as planned. We expect Akatsuki is in the right orbit, but the confirmation comes 2 days later.

— Fifth Star (@5thstar) December 7, 2015

Q: There were applauses around 9:20? A: Project Engineer Mr. Ishii confirmed the ops and I congratulated him. https://t.co/hZp9ehuUCb

— Fifth Star (@5thstar) December 7, 2015

Q: There were no VOI-R1c (correction maneuver)? Nakamura: No, we didn't. https://t.co/C07XI3sC3L

— Fifth Star (@5thstar) December 7, 2015

Q: There seem to be two applauses? Nakamura: I said something then there were applauses... https://t.co/z7ZEsP58Zw

— Fifth Star (@5thstar) December 7, 2015

Q: Were there anything not planned? Nakamura: Nothing particularity. https://t.co/ivUzawh3xb

— Fifth Star (@5thstar) December 7, 2015

Q: What did Mr. Ishii and you say? Nakamura: Ishii said "We conclude the entire ops now", then I said... https://t.co/TTxlC6raN6

— Fifth Star (@5thstar) December 7, 2015

... "We've done what we need to do". In English, I said "A dreams (sic) will come true". https://t.co/TTxlC6raN6

— Fifth Star (@5thstar) December 7, 2015

Q: How you feel now after all those 5 years? Nakamura: Long. I felt so frustrated and shameful not being able... https://t.co/9YbSowXx7E

— Fifth Star (@5thstar) December 7, 2015

... to take data with European (satellite). Now we would like to collaborate with Europeans on data analysis. https://t.co/9YbSowXx7E

— Fifth Star (@5thstar) December 7, 2015

Q: What are the plans now? Nakamura: Will start observation between 14:00 and 17:00. After checking the... https://t.co/LfXSl7wUYR

— Fifth Star (@5thstar) December 7, 2015

... conditions of temp, current, power and confirmed that they are all nominal, we move on to the observation. https://t.co/LfXSl7wUYR

— Fifth Star (@5thstar) December 7, 2015

Q: When do you expect to obtain the data such as the photos? Nakamura: It will be after Dec/10 as the... https://t.co/nKHFdqhO6C

— Fifth Star (@5thstar) December 7, 2015

... high gain antenna will point towards the Earth. There will be more checkout ops. We will release them ASAP. https://t.co/nKHFdqhO6C

— Fifth Star (@5thstar) December 7, 2015

Q: What are the status of the instruments? Nakamura: Before the arrival we tested them. Cameras are... https://t.co/GsxNz3xZ26

— Fifth Star (@5thstar) December 7, 2015

...better shape than expected, but only 3 out of 5 are tested. The remaining 2 need to be tested once we... https://t.co/GsxNz3xZ26

— Fifth Star (@5thstar) December 7, 2015

...start the refrigerator up and running. https://t.co/GsxNz3xZ26

— Fifth Star (@5thstar) December 7, 2015

Q: What are the first objectives of the instruments? Nakamura: 3 cameras, LIR, IR1, UV1 to start with. We'd like to https://t.co/G5RhL4CzFf

— Fifth Star (@5thstar) December 7, 2015

...see the clouds of the Venus. First 3 months are the tunings. Scientific ops starts in next April for two years. https://t.co/G5RhL4CzFf

— Fifth Star (@5thstar) December 7, 2015

Nakamura: We've been only monitoring the health of the satellite so far, but from now on we need to boot up the... https://t.co/8F8EKL1lwO

— Fifth Star (@5thstar) December 7, 2015

...instruments everyday. We don't know what we will see, so we need time to sort them out as more instruments comes. https://t.co/8F8EKL1lwO

— Fifth Star (@5thstar) December 7, 2015

Q: What would you say to Akatsuki? Nakamura: I'd say "You are tougher than I imagined". Vendors did... https://t.co/T1TRDNHCur

— Fifth Star (@5thstar) December 7, 2015

...a great job. I would say it's a battleship grade. Much better than I would hope for. https://t.co/T1TRDNHCur

— Fifth Star (@5thstar) December 7, 2015

Q: You compared the process of the burn to the (kids') university entrance exams. How you feel now? https://t.co/r5WgIrFMoL

— Fifth Star (@5thstar) December 7, 2015

... Nakamura: I now feel "I did it". https://t.co/r5WgIrFMoL

— Fifth Star (@5thstar) December 7, 2015

Q: You plan to change the orbit next year for further obs, how was the fuel comsamptions? Nakamura: As planned. https://t.co/283VxbPp6C

— Fifth Star (@5thstar) December 7, 2015

Q: Comments on Japanese planetary missions? Nakamura: With so few missions we don't have much know-hows yet... https://t.co/g6YjJVmbQ6

— Fifth Star (@5thstar) December 7, 2015

...I realized we learn from experiences. US and Soviet also had many failures in the past...

— Fifth Star (@5thstar) December 7, 2015

...and Japan is just at that stage. https://t.co/g6YjJV4AYy

— Fifth Star (@5thstar) December 7, 2015

Q: Are you worrying about something unusual? Nakamura: No. https://t.co/7m6oCbSU3i

— Fifth Star (@5thstar) December 7, 2015

Q: You said sorry for not achieving the expectations of citizens 5 years ago. Nakamura: I cannot compensate... https://t.co/F9r6s5u5m5

— Fifth Star (@5thstar) December 7, 2015

... their disappointment that time, but I would like to try by taking data. I really thank you for your support. https://t.co/F9r6s5u5m5

— Fifth Star (@5thstar) December 7, 2015

Q: What was the duration of the burn? Nakamura: 1228 seconds. Changed before the original plan. https://t.co/xb7ahLN4rO

— Fifth Star (@5thstar) December 7, 2015

Q: And the time? Nakamura: Started at 08:51:29 JST, ended at 09:11:57 JST. https://t.co/S5QHzllD8s

— Fifth Star (@5thstar) December 7, 2015

Q: Do you think it's in the orbit? Nakamura: Yes. https://t.co/UEltFfHtGm

— Fifth Star (@5thstar) December 7, 2015

Q: About the Obs? Nakamura: High contrast objects will be taken sharply. For more delicate ones we need... https://t.co/UEltFfHtGm

— Fifth Star (@5thstar) December 7, 2015

...to adjust exposures and apertures. That's why we starts from clouds. https://t.co/UEltFfHtGm

— Fifth Star (@5thstar) December 7, 2015

Q: What are the first observation targets? Nakamura: Not decided yet. Trial and Errors. So we need 3 months. https://t.co/UEltFfHtGm

— Fifth Star (@5thstar) December 7, 2015

Torishima: Next conf is 2 days later, Dec/9, after confirming the orbit precisions etc. I will tweet again then. https://t.co/eVfsPY4H3O

— Fifth Star (@5thstar) December 7, 2015

Read more: mission status, Akatsuki (Planet-C), Venus

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