Radio Info

Orbiting Module

DOWNLINK

  • Frequency
    • 437.31MHz
  • Antenna
    • SRR antenna
  • Polarization
    • Linear
  • Modulation
    • beacon, PSK31
  • Sync Word
    • C1 (ASCII code)
  • Power
    • 30dBm

UPLINK

  • Frequency
    • UHF-band
  • Antenna
    • 12M dish
  • Polarization
    • LHCP, RHCP
  • Modulation
    • FSK
  • Sync Word
    • FAF320

The diagram of communication system (OM)

RF system diagram of Orbiting Module

Link Budget PSK31 & PCM-PSK/PM from OM

Link Budget for PCM-PSK/PM

OMOTENASHI overview

OMOTENASHI is 6U CubeSat, and it composed of three parts: Orbintg Module(OM), Surface Probe(SP) and Solid Rocket Motor(SM). The function of Orbiting Module is to bring Surface Probe and Solid rocket Motor to the Lunar Impact Orbit. Next, the unique characteristic of OMOTENASHI is that; it has a solid rocket motor inside! (This cylindrical component is that. ) We have to design a solid rocket motor to decelerate the Moon lander on the landing phase. We put it vertically through the interior and arranged the other components on either side.
At last, the square box on the head of a rocket motor is the moon lander, Surface Probe. As OMOTENASHI has no soft-landing mechanism(such as legs or parashoot), the light and tiny component only can land and survive on the Moon.

OMOTENASHI (Overview)

OMOTENASHI

OMOTENASHI (FM)

OMOTENASHI The communication systems work on X band and UHF band. The X-band LGA is patch antenna and has about 7dBi. In UHF-band, we develop metamaterial antenna for the limited space. As OMOTENASHI is 6U CubeSat, we don't use big connector such as DSub or SMA, and we apply tiny connectors instead, such as MDM or SMPM.

X Transponder and UHF TX/RX

TRP

X Transponder and UHF TX/RX

TRP

Suraface Probe

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  • Frequency
    • 437.41MHz
  • Antenna
    • invert-F antennax4
  • Polarization
    • LHCP(, RHCP)
  • Modulation
    • FM, PSK31, PCM-PSK/PM
  • Sync Word
    • C1 (ASCII code)
  • Power
    • 30dBm

The diagram of communication system (SP)

RF system diagram of Surface Probe

Link Budget PCM-PSK/PM from SP

Link Budget for PCM-PSK/PM of SP

Link Budget for FM Modulation from SP

Link Budget for FM modulation of SP
Though its Solid Rocket Motor is powerful, only Surface Probe can land on the moon. The Surface Probe's weight is just 0.7kg! To reduce its weight, we had to defeature the functions and leave only minimums. Finally, SP has only batteries, OBC, accelerometer, and UHF transmitter(no receiver!).
In the figure below, you can see Surface Probe in the center, and its shape is a rectangular box. The octagon clothes around the SP is an antenna in the UHF band. We array four invert-F antennas to generate circular polarized RF waves; they have a 90 degrees phase difference with the neighboring element. And the Surface Probe is filled with epoxy to endure the landing shock. We fold this antenna when stored in OM, as the last figure shows.

Surface Probe (Overview)

Surface Probe

Surface Probe (Folded)

Surface Probe

Mission Information

  • Verification of the semi-hard landing with airbag and others
  • Development of ultra-compact transponder and solid motor
  • The trajectory design for robust horizontal landing baesd on precision orbit determination
  • Measuring the radiation environment near the Earth and the Moon
mission sequence

The Operation of OM-Communication

It will transmit beacon or telemetry data with PSK31 in somewhere path on the way to the Moon.
That antenna gain is too small, so it is not easy to receive telemetry data. JHRC sends everyone who succeeds in capturing the beacon or carrier signal.

[Please Send Us Info as Below;]

  • The screenshot proves your success recording the signal or telemetry data.
  • The date and location(country) when you record.
  • We could introduce you on our HP or SNS, if you could inform us your receiver equipment and the above.
Either via email or Twitter DM. Of course, with your callsign!

The Operation of SP-Communication

OM turns on the power of SP before separating from OM. Until landing on the Moon, SP emits radio waves with FM modulation by the 3-axis accelerometer in SP. In FM mode, it occupies about 100kHz bandwidth. After landing, the transmission mode is automatically switched to PCM-PSK/PM and sends the digital telemetry.

[Please Send Us Info as Below;]

  • FM mode: Please record the analog data in 100kHz bandwidth. Center frequency is 437.41MHz.
  • PCM-PSK/PM: The screenshot proves your success recording the signal or telemetry data.
  • The date and location(country) when you record.
  • We could introduce you on our HP or SNS, if you could inform us your receiver equipment and the above.
Either via email or file server. Of course, with your callsign!

Orbit Information

[updated on 2022/2/7 JST]
The launch day is now scheduled at April 2022.
Artemis I Update (blogs.nasa.gov)

Tools for JPL Horizon

These program can create POST request to JPL Horizon. To use Haskell code, you need next modules, http-conduit and bytestring.
The orbit format is TLE (two line elements). As soon as the launch date and orbit information is confirmed, it will be announced on this page and SNS (twitter, facebook).

    The diagram of Ground Station (Wakayama & JHRC)

    Ground Station
    As the polarization of the OM antenna is V (or H), we can receive the signal by aligning the polarization plane at the ground station.
    On the other hand, the SP antenna's polarization is normally RHCP when SP lands with the electrical box facing down on the Moon. Thus, we combine the V and H signals with 90 degrees phase difference.
    However, depending on terrain factors and others, we can't rule out the electrical box's possibility of facing up; this means SP's antenna is upside down and seems like LHCP from the Earth. Be prepared for this, our grand station has a polarization switch (R/LHCP SW in the Figure).

    The Diagram of Ground System

    Ground System

    XQuad Antenna

    XQuad Antenna

    XQuad Antenna Pattern

    XQuad Antenna pattern

    Equipped XQuad on Dish

    equipped XQuad

    Other Components

    Item Product Num. Manufacturer Remarks
    SDR IC-9700 ICOM
    TX/RX SW CN-800N TOHTSU I/F: DPDT
    R/LHCP SW RCT RTL-TN1A4
    CPL MODEL QH6258 WERLATONE
    D/C LOW NOISE XTAL OSCILLATOR VHF Design to downconvert to 33MHz
    LNA ZX60-P103LN+ Mini-Circuits Gain:20.3dB(500MHz)
    Logger RSA300Series (x2) Tektronics

    SNS

    Address [English]

    • address: 252-5210 ISAS, Yoshinodai 3-1-1, Sagamihara-shi Chuo-ku, Kanagawa in Japan
    • [Direct to JAXA Ham Radio Club] torii.wataru "at" jaxa.jp
    • convert "at" to @ on sending mail

    Address [Japanese]

    • 住所: 252-5210 神奈川県相模原市中央区由野台3-1-1 宇宙科学研究所
    • [JAXAアマチュア無線クラブ直通] torii.wataru "at" jaxa.jp
    • "at"を@に置き換えてメールください