SATOBS ML, 27 Aug 2021: LED beacon of NAPA-2cubesat imaged!

From: Marco Langbroek via Seesat-l <seesat-l_at_satobs.org>
Date: Sat, 28 Aug 2021 00:56:57 +0200
Hi all,

In cooperation with ISISpace in Delft, who built the satellite, I made a rather
unique observation last night (27 August): the LED beacon of a 6U cubesat,
NAPA-2 (2021-059CN)!

NAPA-2, launched as part of the Transporter 2 rideshare mission on 30 June, is a
6U cubesat in a 520 x 540 km orbit sun-synchronous orbit, built for the Royal
Thai Air Force. It carries two Earth observation cameras.

It also carries an experimental LED beacon (consisting of 12 bright LED's). It
is an experiment to see whether such a beacon can aid in optical tracking of
cubesats.

Over the past week I made 3 attempts to image the beacon, in coordination with
ISISpace who provided me with information on which passes the beacon was active.
They also adjusted the beacon's blink rate to facilitate it being "on" at least
once while passing through the FOV of my camera, and made sure that the
satellite's attitude was such that the beacon pointed into the direction of
Delft and Leiden. The first attempt was negative, the second marginally positive
only, the third attempt (with a larger lens) 100% positive.

The beacon was imaged for two seconds last night and the moment it temporarily
switched off was captured (the beacon was in a "3-seconds-on, 1-second-off" mode).

The beacon was faint (fainter than expected), with an R magnitude of about
+10.2. It was faintly but unambiguously visible in the imagery, taken at 25 fr/s
with a WATEC 902H2 Supreme fitted with a Samyang 2.0/135 mm lens.

Video:
https://vimeo.com/593285105

More imagery (framestacks) and a more elaborate report:
https://sattrackcam.blogspot.com/2021/08/first-positive-observations-of-led.html

You can see the LED's switch off when the satellite is about in the center of
the FOV.


Astrometry:

48963 21 059CN  4353 G 20210827005238401 56 75 0235083+485754 16 S
48963 21 059CN  4353 G 20210827005238441 56 75 0235104+485902 16 S
48963 21 059CN  4353 G 20210827005238600 56 75 0235245+487058 16 S
48963 21 059CN  4353 G 20210827005238920 56 75 0235548+489288 16 S
48963 21 059CN  4353 G 20210827005238960 56 75 0235559+489369 16 S
48963 21 059CN  4353 G 20210827005239241 56 75 0236219+491484 16 S
48963 21 059CN  4353 G 20210827005239561 56 75 0236505+493724 16 S
48963 21 059CN  4353 G 20210827005239600 56 75 0236520+493851 16 S
48963 21 059CN  4353 G 20210827005239761 56 75 0237107+495137 16 S
48963 21 059CN  4353 G 20210827005239801 56 75 0237095+495331 16 S

-----------------------------------------------------------------------------
WATEC 902H2 Supreme + Samyang 2.0/135 mm + GPS time-inserter + TANGRA
What these numbers mean: http://www.satobs.org/position/IODformat.html
-----------------------------------------------------------------------------

Residuals w.r.t. elset 21239.30175625:

     STA   YYday HH:MM:SS.sss   AZ     EL      XTRK    deltaT   Perr
( 1) 4353  21239 00:52:38.401   78.0   60.9   -0.02     0.02    0.023
( 2) 4353  21239 00:52:38.441   77.9   60.9   -0.02     0.04    0.033
( 3) 4353  21239 00:52:38.600   77.7   60.9   -0.02     0.03    0.030
( 4) 4353  21239 00:52:38.920   77.2   61.0   -0.02     0.03    0.025
( 5) 4353  21239 00:52:38.960   77.2   61.0   -0.02     0.06    0.044
( 6) 4353  21239 00:52:39.241   76.7   61.0   -0.02     0.03    0.031
( 7) 4353  21239 00:52:39.561   76.2   61.0   -0.02     0.03    0.031
( 8) 4353  21239 00:52:39.600   76.2   61.0   -0.02     0.05    0.044
( 9) 4353  21239 00:52:39.761   75.9   61.0   -0.02     0.03    0.025
(10) 4353  21239 00:52:39.801   75.9   61.0   -0.03     0.04    0.041

rms     0.03367


At the time of my observation, the satellite was at a range of 598 km, at a sky
elevation of 62 degrees.

It was still in earth shadow at that time, so all the light visible in the video
came from the 12 LED's! Amazing that LED's on a cubesat at almost 600 km can be
imaged!

The LED beacon is not continuously operational: it will only occasionally be
switched on for a few minutes on certain passes, while in reach of a tracking
station.

- Marco


-----
Dr Marco Langbroek  -  SatTrackCam Leiden, the Netherlands.
e-mail: sattrackcam_at_langbroek.org

Cospar 4353 (Leiden):     52.15412 N, 4.49081 E (WGS84), +0 m ASL
Cospar 4355 (Cronesteyn): 52.13878 N, 4.49937 E (WGS84), -2 m ASL
Station (b)log: http://sattrackcam.blogspot.com
Twitter: _at_Marco_Langbroek
-----

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Received on Fri Aug 27 2021 - 17:59:16 UTC

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