Hayabusa - The Return To Earth, The voyage home Options

[RNeuhaus]

December 7, 2005 05:42 PM

According to the L/D of the Matsuura Shin 也...
Bulletin
* The possibility the bullet not being discharged is high
* It has not recovered the thruster
* Ion using the engine, attitude control (Correction: Speaking accurately, applying the function of the ion engine system, attitude control)
* I To matte (Itokawa) as for starting even with most speed after 14 days
* Concerning return undecided

From blog: Paku http://translate.google.com/translate?u=ht...Flanguage_tools

Brief summary from the blog: Matsuura' newspaper

December 2nd. The chemical engine (the thruster) restart was tried, but small thrust is verified in earnest not to start.

December 3rd, it was verified that the high gain antenna axis of the probe and the angle which the sun and the earth form have expanded to 20 or 30 degrees. As the attitude control method of emergency, the xenon gas for ion engine driving it starts the compilation of the operational software to the thing which does the attitude control with the injection.

December 4th, it executes the attitude modification with the xenon gas injection.

December 5th, the sun, the earth and the high gain antenna axis recover to 10 degree - 20 degrees, presently by way of the medium gain antenna communication does at speed of 256 bit /s. However, because the probe slowly is turning, as for the communication by the medium gain antenna intermittence ones such as 1 minute in 6 minutes.

As of December 6th, it is (Hayabusa) quick the (Itokawa) ぶ, from the I To matte in gaze direction it is in the place of the 550km. As for distance from earth 2 hundred million 9000 ten thousand km. Presently just 1 basis the reaction wheel which remains verifies the recovery moving and the revolution with the 1000rpm.

In the other word, now Hayabusa is around 550 km distance from Itokawa and is 290,010,000 kilometers from Earth. (almost just in the opposite side) The RCS z-axis still works at 1,000 rpm.

Rodolfo

[nop]

More translations have been added on the comment area of Matsuura's blog.

[Harder]

The Dec 8 update of the Y.M. Column is now online. The main issues with Hayabusa are already known, but this is a Must Read, if only for the intense atmosphere described in it. I wish them success!

http://www.planetary.or.jp/en/column/index.html

[odave]

From the above:

During its operation Dr. Kuninaka complained, “Oh boy! We’ve already used as much as 100gr of xenon.” followed by the conversation with a staff, “What? Xenon is getting short so seriously?” “Not necessarily right now but xenon costs as much as 1000 yen per 6gr. So, we’ve used up 20,000 yen worth.” “Don’t be so stingy! Beef steak worth 20,000 yen per 100gr is just common all over in Tokyo, I’ve never had it, though.”

That's about $165 US. If Hayabusa makes it home, everyone on the team should get a steak, chased down with LIPOVITAN-D!

[tedstryk]

From the above:
That's about $165 US.  If Hayabusa makes it home, everyone on the team should get a steak, chased down with LIPOVITAN-D!

I have a stupid question...What is LIPOVITAN-D? I know it is something the Hayabusa team drinks, but what is it?

[odave]

I have a stupid question...What is LIPOVITAN-D?  I know it is something the Hayabusa team drinks, but what is it?

It's the Japanese equivalent of Red Bull, a high-energy drink.

[odave]

Lots of good info in those new translations - the volunteer work is much appreciated! For those who haven't read it yet, there is some hope for getting some kind of sample back:

Asahi: What do you think of the possibility that the sample were stirred up by the landing and actually gathered? [...]

Kawaguchi: Escape velocity from Itokawa is equivalent to the speed of a pencil dropped from 0.5 millimeter height. It would only bounce up 0.5mm on earth, but on Itokawa where the gravity is small it would jump up more than 10 meters. Buton the second touchdown, the vehicle actually touched the ground for only a second and ascended back, so the sampler horn ascended with the sample, thus the sample would not have reached the capsule. In the touchdown on 20th the vehicle landed on the surface for substantially long time, so we think it is highly probable that the sample that were stirred up have entered the capsule.

[ljk4-1]

Status of the Hayabusa

December 7, 2005

Japan Aerospace Exploration Agency


As has been reported, it is estimated that part of a series of
attitude and orbit control commands to restore the Hayabusa from its
safe-hold mode have not gone well, and the functions of its major
systems, including its attitude and communication network, have
significantly deteriorated. However, on Nov. 29, a beacon line through
a low gain antenna was restored.

On Nov. 30, we started a restoration operation by turning on and off
the radio frequency modulation through the autonomous diagnostic
function. Subsequently, on Dec. 1, telemetry data were acquired at 8
bits per second through the low gain antenna, although the line was
weak and often disconnected. According to the data transmitted so far,
the attitude and orbit control commands sent on Nov. 27 did not work
well due to an unknown reason, and either major attitude control
trouble or a large electric power loss seems to have occurred. It is
estimated that the overall power switching systems for many pieces of
onboard equipment were reset as their temperature dropped
substantially due to the evaporation of leaked propellant, and also
because of a serious discharge of electricity from the batteries of
many sets of onboard equipment and systems due to declining power
generation. Details are still under analysis.

On Dec. 2, we tried to restart the chemical engine, but, even though
a small thrust was confirmed, we were not able to restore full-scale
operations. Consequently, the cause of the anomaly on Nov 27 is still
under investigation, and we suspect that one of the causes could be
the malfunction of the chemical engine.

On Dec. 3, we found that the angles between the axis of the onboard
high gain antenna (+Z angle) and the Sun, and also that with the earth,
had increased to 20 to 30 degrees. As an emergency attitude control
method, we decided to adopt a method of jetting out xenon for the ion
engine operation. Accordingly, we immediately started to create the
necessary operation software. As we completed the software on Dec. 4,
we changed the spin speed by xenon jet, and its function was confirmed.
Without delay, we sent an attitude change command through this
function.

As a result, on Dec. 5, the angle between the +Z axis and the sun, and
the earth, recovered to 10 to 20 degrees, and the telemetry data
reception and acquisition speed was restored to the maximum 256 bits
per second through the mid gain antenna.

After that, we found that there was a high possibility that the
projectile (bullet) for sampling had not been discharged on Nov. 26,
as we finally acquired a record of the pyrotechnics control device
for projectile discharging from which we were not able to confirm
data showing a successful discharge. However, it may be because of the
impact of the system power reset; therefore, we are now analyzing the
details including the confirmation of the sequence before and after
the landing on Nov. 26.

As of Dec. 6, the distance between the Hayabusa and the Itokawa is
about 550 kilometers, and that from the earth is about 290 million
kilometers. The explorer is relatively moving from the Itokawa toward
the earth at about 5 kilometers per hour.

We are now engaging in turning on, testing, and verifying onboard
equipment of the Hayabusa one by one to start the ion engine. We
currently plan to shift the attitude control to one using the Z-axis
reaction wheel, and restart the ion engine. The restart is expected to
happen no earlier than the 14th. We are currently rescheduling the
plan for the return trip to earth. We need to study how to relax the
engine operation efficiency. We will do our utmost to solve the
problem with the attitude control (such as the restoration of the
chemical engine), then find a solution for the return trip.

Since Nov. 29, our reports have been limited due to difficulties in
confirming telemetry data. We apologize for any inconvenience.
We will inform you as soon as the ion engine is restarted.


This page URL:

http://www.jaxa.jp/press/2005/12/20051207_hayabusa_e.html

---------------------------------------------------------------------

Publisher : Public Affairs Department
Japan Aerospace Exploration Agency (JAXA)
Marunouchi Kitaguchi Building,
1-6-5, Marunouchi, Chiyoda-ku, Tokyo 100-8260
Japan
TEL:+81-3-6266-6400

JAXA WEB SITE :

http://www.jaxa.jp/index_e.html

[RNeuhaus]

Hope that Hayabusa has a match fire on their side for just in the case that the ion engine won't also be able to be ignited....

I am pessimist of a good trail of "mishapes".

Rodolfo

[The Messenger]

Since the xenon was not intended to be used as an attitude control gas, Are they using a venting valve to adjust the spin and attitude, or can they run zenon into the attitude control system?

In either case, the calculations are quite complex: They would have to maintain a slow rotation rate, and vent the gas at just the precise moment for the right percentage of the roll to adjust the tilt. It would take a very careful trial-and-error assessments to do this (the ultimate $170million dollar video game...and a lot of Lipovan

[ljk4-1]

FATE OF JAPAN'S TROUBLED ASTEROID PROBE UNCERTAIN
-------------------------------------------------

Japanese officials are struggling to fix a horde of problems plaguing the
Hayabusa space mission in time to begin its journey back to Earth with or
without a package of specimens that were supposed to have been collected
from the surface of asteroid Itokawa late last month.

http://spaceflightnow.com/news/n0512/11hayabusa/

[odave]

Since the xenon was not intended to be used as an attitude control gas,  Are they using a venting valve to adjust the spin and attitude, or can they run zenon into the attitude control system?

From Matsuura's blog, it sounds like they're venting the xenon through the ion engine nozzles:

NHK How is the attitude control by xenon gas, concretely?

Kawaguchi: The vehicle has four ion engines, and the orifice of each engine has a neutralizer with four nozzles per engine in order to neutralize the jet gas electrically. The nozzles are openable and closable. By opening or closing the nozzles to emit neutralized xenon gas jets, we are controlling the attitude. Its propulsion force is very small.

Kawaguchi goes on to say that if they are forced to use xenon for attitude control on the trip back, they'll need to stop the ion engines every time they need to adjust attitude, then re-start the engines for thrust afterward. That will be a time consuming process and quite an exercise in patience.

[amezz]

Press Conference about Hayabusa present status, will held at 9:30 14rh Dec. JST.

S.MATSU intend to upload Japanese article at 11:00 or so here http://smatsu.air-nifty.com/lbyd/

[elakdawalla]

Just added this to my blog, I thought I'd add it here for all of your benefit too...We just received the following update from Tasuku Iyori of The Planetary Society of Japan regarding Hayabusa:

JAXA announced to the press that it decided to put off Hayabusa's departure from Itokawa after next fall, thereby expecting spacecraft's return to Earth around 2010. Nothing in detail has yet been reported on the website.

--Emily

[Guest_BruceMoomaw_*]

I very much doubt it will be around by then, and I'm afraid we will soon be able to add Hayabusa to Japan's almost unbroken modern record of space failures -- although at least it came a good deal closer to success than most of Japan's missions do. Space missions simply cannot be done on such low funding levels.

I shudder to report that -- according to the Nov. 28 Aviation Week -- JAXA has been taking its advice on how to reform its space program from Dan Goldin.