Old UNID was Vostok 2 and its rocket body

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Sat, 29 Aug 2015 13:17:14 -0400
Project Blue Book case 7562, was the brief sighting on 1961 Aug 6, from the Pacific Ocean in the Far East, of 2
pulsating objects, one behind the other, headed south. The five page case file begins here:

https://www.fold3.com/image/8297683

One of the witnesses reported the sighting to the U.S. Navy, in a letter written on 1961 Aug 07 on United States Lines
letterhead, the body of which stated:

"While on route to Manila from Honolulu, on course 267 deg true at exactly 0800 8/6/61 GMT, 2000 Local time, Lat: 22 deg
27 min N, Long: 175 deg 19 min E, two objects were observed in the sky by myself and two AB'S [able seamen] while on
watch.

On this dark clear night, these two objects, one behind the other and pulsating, were picked up bearing 315 deg true,
and crossed the sky from North to South.

They appeared for approximately 10 seconds at an approximate speed of 9 times the speed of U.S. Satellite Echo. The two
objects passed over having a sextant altitude of 53 deg 26.5 min, approximately the same height as the star Arcturus, at
that time."

On Aug 24, the Navy forwarded the letter to NASA. On Sep 20 NASA/GSFC forwarded it to the "Foreign Technical
Intelligence Center" at Wright-Patterson AFB. (Most likely, they meant the Aerospace Technical Intelligence Center,
which in July 1961 became the Foreign Technology Division of the newly established Air Force Systems Command.)

Project Blue Book listed the case as Insufficient Data for Evaluation, with the following comments: "It is possible that
this was either a missile or meteor. Pulsating effect tends to lead to missile evaluation, however, there was no known
launch this date."

It occurred to me that this might have been a re-entry. I found that the rocket body of Vostok 2 was reported to have
decayed 3 days later - too late for the re-entry hypothesis, but it led me to check the launch information of Vostok 2.
It had been launched two hours before the sighting, at 06:00 UTC, piloted by cosmonaut Major Gherman Titov on his one
day mission.

Jonathan McDowell has the TLEs of Vostok 2 (1961-019A / 168) and its rocket body (1961-019B / 169), which are the same
as those at Space Track:

http://www.planet4589.org/space/elements/00100/S00168

http://www.planet4589.org/space/elements/00100/S00169

There are two TLEs of each object, all of which are in reasonable agreement with the sighting in question, but with
considerable variance among them. In those days, the initial elements of new launches were not very accurate, so the
variance is not surprising.

On the assumption that the second TLE of Vostok 2 (epoch 61218.85853340) was the more accurate of the two, I used it to
compute an ephemeris of the key events:

   UTC    AZ EL
07:55:12 333  0 rose
07:58:07 315 42 reported bearing of first sighting
07:58:17 303 54 reported altitude of sextant measurement of elevation
07:58:32 248 68 culminated
07:58:36 224 67 entered penumbra
07:58:46 190 55 disappeared into umbra
08:02:11 159  0 set while in eclipse

The temporal and spatial correlation is strong. The time was within 2 min, of the sighting report. The track passed
through azimuth 315 deg, southbound.

Arcturus was near azimuth 271 deg, at 56.6 deg elevation, in agreement with the comment that it had been at about the
same elevation as that of the two objects, as measured with a sextant.

The duration of the sighting was limited by entry into eclipse, which is imprecisely known. The TLEs vary greatly
regarding the time of this event. The above eclipse time is considerably earlier than those of the other TLEs. It
indicates a total sighting duration of 30-40 s, quite a bit longer than the reported 10 s. Imprecise recollection of the
duration and imprecise TLEs probably account for the discrepancy.

The witness reported that the speed had been approximately 9 times that of Echo 1 (1960-009A / 9). The peak angular
velocity of Vostok 2 was 2.24 deg/s. He did not specify a particular pass of Echo 1, but it did happen to make a 47 deg
elevation pass less than 30 min. before Vostok 2, during which its peak angular velocity was 0.23 deg/s. That would
have made Vostok 2's angular velocity 9.7 times that of Echo 1. He could well have observed Echo 1 on other occasions
and measured its angular velocity.

The TLEs of the rocket body reveal that it passed at about the same time as its payload, with the aforementioned large
variances in track. I have no reason to doubt that they were in fact still close together, with one appearing to follow
behind the other.

One discrepancy between Vostok 2 and the sighting report, is the statement that both objects had pulsated. The rocket
body could well have gone into a rapid spin (tumble), but the Vostok was stabilized. I suspect that the witness was
either imprecise in making the description, or was mistaken in his recollection of the reportedly brief sighting.

Sven Grahn's report on Vostok 2 from primarily the radio observation perspective provides further context to the visual
sighting:

http://www.svengrahn.pp.se/histind/Vostok2/vostok2.html

Twenty minutes prior to the sighting, "at 0738 UT, after completing first orbit, Titov and Khrushchev exchanged
greetings."

Ted Molczan





_______________________________________________
Seesat-l mailing list
http://mailman.satobs.org/mailman/listinfo/seesat-l
Received on Sat Aug 29 2015 - 12:18:06 UTC

This archive was generated by hypermail 2.3.0 : Sat Aug 29 2015 - 17:18:07 UTC