[meteorite-list] Newly Discovered Object Could be a Leftover Apollo Rocket Stage (J002E3)

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From: James_TOM Knudson <peregrineflier_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:24 2004
Message-ID: <F59p8fqwZVkdU8ASJTe0000d0a6_at_hotmail.com>

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<P>Ron, I want to thank you for your posts. Besides the posts back and forth between the list and Steve Arnold, you have the most Interesting posts of them all! : ) I have learned so much from your posts! This list was a great idea and people like you add to its greatness! Please keep them coming!<BR>Thanks, Tom</P>
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<DIV></DIV>From: Ron Baalke <BAALKE_at_ZAGAMI.JPL.NASA.GOV>
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<DIV></DIV>To: meteorite-list_at_meteoritecentral.com (Meteorite Mailing List)
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<DIV></DIV>Subject: [meteorite-list] Newly Discovered Object Could be a Leftover Apollo Rocket Stage (J002E3)
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<DIV></DIV>Date: Wed, 11 Sep 2002 19:03:28 -0700 (PDT)
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<DIV></DIV>Newly Discovered Object Could be a Leftover Apollo Rocket Stage
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<DIV></DIV>Paul Chodas
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<DIV></DIV>Near-Earth Object Program Office
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<DIV></DIV>September 11, 2002
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<DIV></DIV>An analysis of the orbital motion of the newly discovered
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<DIV></DIV>object J002E3 indicates that it could be a leftover Saturn V
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<DIV></DIV>third stage from one of the Apollo missions, most likely
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<DIV></DIV>the Apollo 12 mission, launched on November 14, 1969.
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<DIV></DIV>The new object was discovered on September 3 by Bill Yeung,
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<DIV></DIV>who noted that it was moving quite rapidly. Initial orbit
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<DIV></DIV>computations by the Minor Planet Center indicated that the
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<DIV></DIV>object was only about twice as far away as the Moon, and
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<DIV></DIV>was actually in orbit about our planet. This fact, combined
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<DIV></DIV>with the rather faint intrinsic magnitude, immediately led
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<DIV></DIV>astronomers to suspect that the object is actually a
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<DIV></DIV>spacecraft or rocket body, not an asteroid. But the object
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<DIV></DIV>could not be associated with any recent launch.
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<DIV></DIV>J002E3 is currently observable at magnitude 16.5; it is
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<DIV></DIV>easily detectable in asteroid surveys, and even bright enough
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<DIV></DIV>to be seen by many amateur astronomers. If it is a
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<DIV></DIV>leftover piece from an old launch, why was it not discovered
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<DIV></DIV>until last week? A backwards analysis of the orbital motion
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<DIV></DIV>provides the answer: the object was apparently captured by
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<DIV></DIV>the Earth from heliocentric orbit in April of this year.
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<DIV></DIV>The capture occurred when the object passed near the Earth's
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<DIV></DIV>L1 Lagrange point, a location where the gravity of the Earth
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<DIV></DIV>and Sun approximately cancel. This point serves as "portal"
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<DIV></DIV>between the regions of space controlled by the Earth and Sun.
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<DIV></DIV>J002E3 is the first known case of an object being captured
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<DIV></DIV>by the Earth, although Jupiter has been known to capture
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<DIV></DIV>comets via the same mechanism. (For example, Comet
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<DIV></DIV>Shoemaker-Levy 9, which collided with Jupiter in 1994, had
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<DIV></DIV>been captured by Jupiter decades earlier.)
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<DIV></DIV>Analysis of J002E3's pre-capture orbit about the Sun
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<DIV></DIV>shows that the object was always inside the Earth's
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<DIV></DIV>orbit, and that it may have come within the Earth's
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<DIV></DIV>vicinity in the early 1970s or late 1960s. Many of the
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<DIV></DIV>test cases in our analysis in fact passed through
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<DIV></DIV>the L1 portal, back into Earth orbit (going backwards
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<DIV></DIV>in time) during the early 1970s. In other words, this
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<DIV></DIV>object was very likely orbiting the Earth during
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<DIV></DIV>this period before escaping into the heliocentric orbit
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<DIV></DIV>from which it was captured in 2002. It seems quite
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<DIV></DIV>likely that this object is one of the Apollo Saturn
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<DIV></DIV>S-IVB third stages which flew by the Moon during this
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<DIV></DIV>era (Apollos 8 through 12). The brightness of J002E3
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<DIV></DIV>seems to match the expected brightness of an S-IVB
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<DIV></DIV>stage. Further circumstantial evidence suggests that
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<DIV></DIV>this object is in fact the Apollo 12 stage, which was
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<DIV></DIV>left in a very distant Earth orbit after it passed by
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<DIV></DIV>the Moon on November 18, 1969. This spent rocket body
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<DIV></DIV>was last seen in an Earth orbit with a period of 43
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<DIV></DIV>days, not much different from J002E3's current orbit.
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<DIV></DIV>The future motion of J002E3 is also very interesting.
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<DIV></DIV>A similar orbital analysis which takes into account
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<DIV></DIV>the current orbit uncertainties shows that the object
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<DIV></DIV>has a surprisingly large 20 percent chance of impacting
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<DIV></DIV>the Moon in 2003. Such a lunar impact would not be
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<DIV></DIV>unprecedented: NASA intentionally impacted five Apollo
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<DIV></DIV>S-IVB stages on the Moon from 1970 through 1972
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<DIV></DIV>(Apollos 13 through 17), as an experiment to study the
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<DIV></DIV>interior structure of the Moon. Looking further into
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<DIV></DIV>the future is problematic, due to the chaotic nature of
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<DIV></DIV>J002E3's orbit, but our current analysis shows the object
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<DIV></DIV>to have about a 3 percent chance of impacting the Earth
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<DIV></DIV>within the next 10 years. This should not be of
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<DIV></DIV>concern to the public. Apollo stages have impacted the
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<DIV></DIV>Earth before, in the 1960s, and the larger Skylab
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<DIV></DIV>re-entered in the 1970s. (The even larger Mir Space
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<DIV></DIV>Station was intentionally impacted into the Pacific
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<DIV></DIV>Ocean in March 2001.)
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<DIV></DIV>Additional positional observations of this object are
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<DIV></DIV>being received daily, and our knowledge and modeling of
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<DIV></DIV>its orbit continues to improve. The collision
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<DIV></DIV>probabilities mentioned above will change as we are able
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<DIV></DIV>to make more precise predictions.
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<DIV></DIV>Animations showing how J002E3 was captured into
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<DIV></DIV>its current chaotic orbit around the Earth are available
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<DIV></DIV>on the Near-Earth Object Program website:
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<DIV></DIV>http://neo.jpl.nasa.gov
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<DIV></DIV>______________________________________________
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<DIV></DIV>Meteorite-list mailing list
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<DIV></DIV>Meteorite-list_at_meteoritecentral.com
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<DIV></DIV>http://www.pairlist.net/mailman/listinfo/meteorite-list
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Received on Thu 12 Sep 2002 01:00:01 AM PDT

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