Artemis 1: magnitude estimates

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Sun, 28 Aug 2022 18:06:01 -0400
Artemis 1 is scheduled for launch from KSC on 2022 Aug 29 at 12:33 UTC.

JPL Horizons has ephemerides of the spacecraft. I did not check Horizons for any other pieces from the launch.

https://ssd.jpl.nasa.gov/horizons/app.html

Horizons does not have magnitude estimates for Artemis 1, so I have made rough estimates.

Based on dimensions published by NASA, I have estimated standard magnitude (1000 km range, 90 deg phase angle) of 4.6 for the Orion spacecraft, and 3.9 for the final stage of the booster plus spacecraft adapter. The estimated uncertainty of both is 2 magnitudes.

Below are magnitude estimates for a variety of ranges, for 100% illumination and 50% illumination. Since Horizons states range in astronomical units, I have done likewise and included the km equivalent. Note: Horizons uses the term delta for range.

      Range       Estimated Magnitude
   AU        km   100% Ill.  50% Ill.
0.00001     1496     4.2       5.5
0.00002     2992     5.7       7.0
0.00003     4488     6.6       7.9
0.00004     5984     7.2       8.5
0.00005     7480     7.7       9.0
0.00006     8976     8.1       9.4
0.00007    10472     8.5       9.7
0.00008    11968     8.7      10.0
0.00009    13464     9.0      10.2
0.00010    14960     9.2      10.5
0.00020    29920    10.7      12.0
0.00030    44879    11.6      12.9
0.00040    59839    12.2      13.5
0.00050    74799    12.7      14.0
0.00060    89759    13.1      14.4
0.00070   104719    13.5      14.7
0.00080   119678    13.7      15.0
0.00090   134638    14.0      15.2
0.00100   149598    14.2      15.5
0.00110   164558    14.4      15.7
0.00120   179517    14.6      15.9
0.00130   194477    14.8      16.0
0.00140   209437    15.0      16.2
0.00150   224397    15.1      16.3

Uncertainty = 2 magnitudes
Subtract 0.7 mag for rocket body

Happy hunting!
Ted Molczan




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Received on Sun Aug 28 2022 - 17:07:41 UTC

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