Ten-Koh 2 deploy from HTV-X1

Satellites & Observations Launches
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Saw the below on the AMSAT mailling list. Looks like at least some of the payload will operating on the amateur band. Probably worth keeping an eye out for more information nearer launch / deployment.

https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org/thread/TVLEGIYNMC7YGHFS7FTHFNYU26EYJA2G/

Ten-Koh 2 will be deployed from JAXA’s new transfer vehicle, HTV-X1.

HTV-X1, the first unit of JAXA’s new transfer vehicle HTV-X, will
carry Ten-Koh 2 to the ISS. After being berthed at the ISS, HTV-X1
will raise its altitude to approximately 500 km. Following this
maneuver, Ten-Koh 2 will be deployed from HTV-X1 using the HTV-X
Small Satellite Orbital Deployer(H-SSOD).

The deployment date has not been announced. It will be NET December.

transponder downlink: 435.875 - 435.915 MHz
transponder uplink: 145.895 - 145.935 MHz
experiment downlink: 435.895 MHz AFSK, Digitalker, 4k8-38k4 GMSK, 38k4 4FSK
CW beacon: 5839.000 MHz

PS: HTV-X1 will deliver six CubeSats to the ISS. KNACKSAT-2 and
UiTMSAT-2 will operate on amateur radio bands. They are expected
to be deployed from the ISS in November.

KNACKSAT-2

UiTMSAT-2

73

Masa JN1GKZ Tokyo, Japan

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any update?

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Sorry not seen any updates. A local UK radio supplier (moonraker) has posted on its socials about it but saying deployment “not before December 2025”. Guess we need to watch for announcement from the team..

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Update!

Screenshot from 2026-02-22 01-49-51
Screenshot from 2026-02-22 01-49-51609×636 66.7 KB

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PDF documents spelling out the CW telemetry formatting as well as the FM downlink telemetry formatting are available for download from:

To Amateur Radio Operators – 奥山研究室

as well as a nice freq. chart:

ten-koh-2_freqs
ten-koh-2_freqs874×485 46.7 KB

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Ok, moments ago HTV-X1 disconnected from the ISS. Anyone know what the schedule is for any satellite deployments?

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According to the official JAXA broadcast, the Ten-Koh 2 deploy is scheduled for about a week from now.
The specific schedule will likely be announced later.

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JAXA-related accounts have announced that the release of Ten-Koh 2 from HTV-X (the H-SSOD system demonstration mission) will take place in the near future. The exact date and time are still unknown.

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image898×813 109 KB

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[Breaking] The release of Ten-Koh 2 from HTV-X transpired without prior notification.
The initiation of observations is imperative.
The release time was around 2026-03-11 09:35 (UTC).

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image712×831 141 KB

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On it to add TLE and change status on DB and start scheduling. Thanks for the notice!

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11

For now I’m going to use HTV-X1 TLE:

0 HTV-X1
1 66174U 25241A   26069.48132270  .00008982  00000-0  17350-3 0  9994
2 66174  51.6323  68.4424 0007951 177.3713 182.7319 15.48562437554476

The same TLE changed to use the tempory NORAD ID:

Ten-Koh 2
1 98542U 25241A   26069.48132270  .00008982  00000-0  17350-3 0  9998
2 98542  51.6323  68.4424 0007951 177.3713 182.7319 15.48562437554470
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12

Please note that Celestrak still has the TLE for HTV-X1 showing as docked to the ISS @ approx. 429km altitude… very distant from the 500km target altitude for deployment of Ten-Koh 2.

So, until / unless that HTV-X1 TLE gets updated, the only hope for any RX reports from Teh-Koh 2 will be from constant monitoring w/ an omni antenna.

Better yet, of course, would be a permanent Object # & TLE for Ten-Koh 2 itself.

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I’m wondering if the 435.860 MHz is right because in IARU coordination I don’t see this frequency listed.

Anyway I’ll schedule a couple of observations on this frequency too, just in case.

EDIT: I’ve just checked and the frequency is in the ITU entry for the satellite.

Good point, space-track.org TLE above seems to be in the same status, let’s hope that HTV-X1 is not far away from ISS.

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The Teh-Koh 2 Team kindly reached out to me last night and 435.860 MHz is the correct freq. for the initial CW beacon

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I don’t know if this is possible in SatNogs (absent an accurate TLE), but it’s my understanding that Ten-Koh 2 at the ~500km altitude is currently running approximately 23 minutes behind the HTV-X1 / ISS position using the current TLE.

If that offset cannot be factored into SatNogs observations, then anyone manually watching for Tek-Koh 2 should factor in that difference for their local tracking.

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There is a new TLE in space-track.org:

0 HTV-X1
1 66174U 25241A   26070.19118651  .00009215  00000-0  17770-3 0  9997
2 66174  51.6325  64.9326 0007932 179.9008 180.1983 15.48575655554479

And with the temporary NORAD ID in DB:

Ten-Koh 2
1 98542U 25241A   26070.19118651  .00009215  00000-0  17770-3 0  9991
2 98542  51.6325  64.9326 0007932 179.9008 180.1983 15.48575655554473

EDIT: This TLE also is like to be similar to the ISS one, I’ll take a more detailed look and see if we can have something better.

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Both are at 416 km.

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Ten-Koh 2’s TLE has been released. It is as follows.

1 66174U 25241A   26068.00000000  .00001847      0-0  77728-4 0 00008
2 66174  51.6328  76.1223 0005874 167.3547  35.4429 15.22787692000308

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I will check my STRF obs when the satellites has passed Europe (18:45 UTC).

Jan | PE0SAT

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TLE changed to follow the temporary NORAD ID in DB:

Ten-Koh 2
1 98542U 25241A   26068.00000000  .00001847  00000-0  77728-4 0 00002
2 98542  51.6328  76.1223 0005874 167.3547  35.4429 15.22787692000302

and the same TLE propagated to a more recent epoch to use to DB as the latest one:

Ten-Koh 2
1 98542U 25241A   26070.19118652  .00000000  00000-0  00000-0 0    03
2 98542  51.6328  65.7002 0005874 258.8299  83.9218 15.22796273    07

Due to the significant difference I’m going to remove all the future observations in Network and re-schedule observations, if any station owner has scheduled any observation, please proceed to re-schedule.

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