

FITSAT-1 (NIWAKA)

A Small Artificial Satellite Developed at the Fukuoka Institute of Technology FITSAT Project: Takushi Tanaka (JA6AVG) News ********************************************************************

"Web Based Observatory" helps to find flashing NIWAKA.

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Project Member

Main Mission We developed a 5.84GHz high speed transmitter for artificial satellites.

It consists of an exciter module with a 115.2kbps FSK modulator and

a liner amplifier which amplifies a 10mW signal to 4W.







But, these two modules were too big for a cube-sat. So, we have developed a

new module which combines the exciter and the liner amplifier of 2W output.







Using this module, we have developed a small artificial satellite

named FITSAT-1. It also has the nickname "NIWAKA".

The shape is a 10cm cube, and the weight is 1.33kg.



The main mission of this satellite is to demonstrate the high speed

transmitter developed. It can send a jpeg VGA-picture(480x640)

within 6 sec.







Radio

NIWAKA uses the 430MHz band for beacon transmission and remote commands.



The beacon signal is a standard Morse code CW signal.

The signal starts with "HI DE NIWAKA ..." and telemetry data follows.





(telemetry format)











NIWAKA also sends telemetry data stored by 1200bps AX.25 packets.

It is on demand, so not always send the packets.

The format is here.







The following table summarizes the radio frequencies of NIWAKA.









Second Mission

NIWAKA has another experimental mission to test the possibility of optical

communication by satellite. It will actually twinkle as an artificial star.



NIWAKA's high power LEDs will be driven with more than 200W pulses to

produce extremely bright flashes. These, we hope, will be observable by

the unaided eye or with small binoculars.



NIWAKA will write messages in the night sky with Morse code as:





(JAXA movie 120MB)





The LEDs will also be driven in detecting faint light mode.

The light will received by a photo-multiplier equipped on telescope

aligned with the 5.84GHz parabolic antenna.



Duty 30%, 10Hz signal is modulated with also duty 30%, 5kHz signal.

So the average input power will be 220W x 0.3 x 0.3 = 20W.

In order to detect the faint light, a high gain band pass amplifier with

the central frequency of 5kHz may be useful.



While, the Morse code is modulated with duty 15%, 1kHz signal. So, the

signal can directly drive a speaker with AF-amplifier to hear Morse sound.







Overview (Flight Model)







(Bottom View)







Structure

The NIWAKA body is made by cutting a section of 10cm square aluminum

pipe. Both ends of the cut pipe are covered with aluminum plates.

The surface of the body is finished with black anodic coating.







The CubeSat slide rails and side plates are not separate; they are

made as a single unit. The thickness of the square pipe is 3mm, but

the surfaces attached by solar cells are thinned to 1.5mm because of

weight limit. In order to make the 8.5mm square CubeSat rails, 5.5mm

square aluminum sticks are attached to the four corners of the square pipe.







The following picture shows the inside of NIWAKA.







The "L" at upper left is a lever to push the deployment switch.

The rotor at upper center is 437MHz antenna extension mechanism.

The antenna element is stored in a polycarbonate case in spiral.

This mechanism was developed by Mr. T.Otsuka who was an undergraduate

student of Intelligent Mechanical Engineering Department.

There are connectors for flight pin and testing functions at upper right.







Block Diagram







Orbit

The trajectory of the ISS is inclined 51.6 deg from the equator, so NIWAKA will

travel between 51.6 degrees south latitude and 51.6 degrees north latitude.



NIWAKA will carry a mounted neodymium magnet to force it to always point to

magnetic north like a compass. When NIWAKA rises above the horizon, it will

be to the south of the Fukuoka ground station, and both the 5.84GHz antenna

and the LEDs will be aimed accurately enough by the magnet aligning itself

and the satellite with the earth's magnetic field that the Fukuoka ground

station will be within the main beams.



We will perform both 5.84GHz high-speed and optical communication experiments

for about 3 minutes as the satellite travels along the orbit shown as the red

line in the figure.















Naming

The name NIWAKA is from "Hakata Niwaka", which is traditional impromptu comical

talking with this mask. Here, Hakata is old name of Fukuoka city.





Deployment

NIWAKA was launched from the International Space Station

at 15:44 on 4th October 2012 (UTC) as shown here.





(JAXA movie 60MB)



After Deployment from NASA pictures













Ground Station







The 5.840 GHz signal is converted to 440 MHz with LNB which is attached

to the focal point of 1.2m parabola antenna. The parabola is mounted on

an equatorial telescope.











The 440 MHz signal is converted to 10.7 MHz by AR8600 receiver.

The 10.7 MHz signal is detected by 280/500 kHz FM detector.

As we use a simple FSK, FM detector directly generates RS232C

signal for PC.











A jpeg-picture data consists of 128 bytes packets as follow:



(Photo Data)



00 00 7A 00 FF D8 FF E0 ...

01 00 7A 00 09 0A 16 17 ...

...

12 34 56 00 ..... FF D9 ...





Namely, the first 4 bytes and the last 2 bytes do not consist the

photo data. Data size of all packets except the last is 122(=7A hex).

A jpeg-picture data starts with "FFD8" and ends with "FFD9".

The jpeg picture is made by connecting the data part of each packet by

removing the first 4 byte and the last 2 byte.

20 VGA-pictures are sent at a time. Each picture is sent around 4-6 sec.

There is 8 msec interval between packets. and 5 sec interval

between pictures.





Circuit Schematics

Software

I appreciate Timothy HB9FFH who made a telemetry decoder for FITSAT-1. It is available from the Carpcomm website: http://carpcomm.com/satellite/fitsat1 He made the program based on the column "Radio" of this web-page. I found an error in the column written in red character. So, please 3 times the value of s22. One of our student also made the similar software on windows: CW-Analyzer All programs for 5.84GHz are developed on Linux. A simple shell script controls receiving data and displaying pictures. Here is tgz file which we have developed.

References

Current position

Verification Card

FITSAT sends the beacon signal 30 min after the deployment. Please send

the signal report and your postal address to fitsat1@hotmail.co.jp and

also cc to tanaka@fit.ac.jp. You will receive this verification card.



The beacon frequency 437.250MHz of FITSAT-1 conflicts with the satellite

PRISM of Tokyo Univ. Please confirm that the CW starts "HI DE NIWAKA ...".



The orbit is almost same as ISS.







TV News (in English)



(NHK-international-TV 2012.07.23 56MB)







TV News (in Japanese)



(KBC-TV 2012.06.24 8.7MB)









(NHK-TV 2012.06.25 39MB)









(NHK-TV 2012.10.05 83MB)









(RKB-TV 2012.10.05 78MB)









(FBS-TV 2012.10.29 44MB)









(TV-Tokyo 2012.12.06 148MB)



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(NHK-TV 2012.07.14 40MB)





You tube Movie



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