Debris from re-entered 2016-050B recovered in Indonesia

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Mon, 26 Sep 2016 17:51:54 -0400
Joseph Remis has reported news of the recovery of COPV helium pressurant tanks in Indonesia, from the recently
re-entered Falcon 9 rocket body, 2016-050B / 41730. His message is on the ReentryWatch mailing list:

https://groups.google.com/forum/#!forum/reentrywatch

Muh Ma'rufin Sudibyo identified 2016-050B / 41730 as the source of the debris:

https://ekliptika.wordpress.com/2016/09/26/roket-falcon-9-full-thrust-penerbangan-28-jatuh-di-pulau-madura/

Upon receipt of this report, I propagated the final TLE (epoch 16269.99471699) to decay using GMAT 2015a. I obtained
theoretical impact on 2016 Sep 26 at 02:27:25 UTC, near 6.4 S, 116.0 E, which would be the approximate toe of the debris
footprint. USSTRATCOM reported 02:26 UTC and 5.8 S, 117.5 E.

Shortly after 02:21 UTC, the GMAT-propagated re-entry trajectory passed less than 10 km SSE of the islands Gili Radja
and Giligenting, where COPV tanks were recovered. For perspective, consider that about 97 percent of the recovered
debris of space shuttle Columbia was found within 5 NM (9 km) of its re-entry ground track. In this case, that depends
on the wind having blown from the SSE (I have not researched the actual wind direction).

The decay analysis is highly sensitive to the perigee height given by the TLE, which probably was not all that accurate,
given the difficulty in tracking re-entries from HEO. If a more accurate perigee could be estimated, perhaps by
evaluating more than one of the final TLEs, it could shift the re-entry ground track somewhat.

Here is a plot of the re-entry ground track showing the general region of the debris fall:

http://satobs.org/seesat_ref/misc/16050B_re-entry_trajectory_1.jpg

The alternating red and white line segments depict 5 seconds of flight.

Here is a close-up view of the islands where the debris was found:

http://satobs.org/seesat_ref/misc/16050B_re-entry_trajectory_2.jpg

The kml file containing the 2D and 3D trajectory is here:

http://satobs.org/seesat_ref/misc/2016-050B_re-entry.kml

Use the 2D trajectory to display the ground track, and the 3D to display the trajectory as seen from the Earth.

An ephemeris spreadsheet is available below. It can be used to evaluate sighting reports. The event occurred in
darkness, but it is not clear to me from the above report that there were any sightings; however, I believe there is
mention of what could have been a sonic boom.

http://satobs.org/seesat_ref/misc/16050B_re-entry_ephemeris_v1.xlsm

The spreadsheet opens to an ephemeris for Giligenting. In addition to the usual sky track data, the surface distance
from the observation site to the trajectory is reported in col 15. Ephemerides for different locations can be computed
by editing the co-ordinates at col 15, rows 2-4. A VBA script in this file generated the place mark data for the kml
files.

The GMAT 2015a script that generated the trajectory data embedded in cols 20-26 of the above spreadsheet is here:

http://satobs.org/seesat_ref/misc/16050B_1.script

It may be necessary to edit the file paths at line 52 and 57. The latter points to a file of space weather data, named
sw19571001b.txt. It consists of data downloaded today from Dr. T.S. Kelso's CelesTrak site. Use the contents of either
of the two files on that page.

http://celestrak.com/SpaceData/

Ted Molczan


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Received on Mon Sep 26 2016 - 16:52:41 UTC

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