[meteorite-list] Scientists Find an 'Asteroid' is Apollo 12 Debris

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:37 2004
Message-ID: <200310311622.IAA07445_at_zagami.jpl.nasa.gov>

http://planetary.org/html/news/articlearchive/headlines/2003/apollo12-debris.html

Scientists Find an 'Asteroid' is Apollo 12 Debris
      
Anatomy of an Asteroid Investigation

By A.J.S. Rayl
The Planetary Society
30 October 2003

Heaven and Earth are about to collide . . . An asteroid the size of Texas is
speeding directly toward Earth at 22,000 miles per hour and NASA's executive
director has only one option -- to send up a crew to destroy the asteroid . . .
(1)

It was only a movie. But Armageddon and other films of
its ilk back in the late 1990s presented an image of
asteroid fear and injected it into a public consciousness
that ebbs and flows today.

The more our ability to 'see' in space has improved and
the more missions we send into space, the more we know
there are all kinds of things flying around out there
that could someday, somehow, somewhere drop in on Earth.
That knowledge -- along with evidence of past meteor and
asteroid impacts on Earth and other planets, and those
thought-provoking Hollywood movies - has fueled public
intrigue and concern about anything out of the ordinary
that might be orbiting our world.

Just a glance at a map showing the space debris around our planet reveals that
we are literally encircled in junk, and the prospects for disaster in
imaginative minds can loom large. In reality, however, the general public can
rest assured about one thing: all kinds of people are keeping close watch over
the heavens above.

Every few weeks, automated asteroid surveys scan the skies
looking for any errant space rocks or anything else that's
out of the ordinary and moves. Nothing of any interest, no
matter what it might ultimately turn out to be -- an
asteroid or a piece of space junk, or even an
extraterrestrial spacecraft -- is going to get by this
global group of astronomers and researchers who represent all variety of space
science fields.

Virtually every object that dares venture near our planetary airspace is
detected, analyzed, and scrutinized with multiple methods, almost always from
multiple observatories. In the vast majority of cases, the objects turn out to
be rather docile and non-threatening.

A case in point is the mysterious object found in orbit around the Earth (about
twice as far away as the Moon) by Hong Kong born, Canadian amateur astronomer
Bill Yeung in September 2002. Known as J002E3, Yeung had reason to believe it
was an authentic asteroid and a group of scientists thought it was interesting
enough to take notice and investigate the object every astronomical which way.
How they finally came to the almost unequivocal conclusion that it was actually
the third stage of the Saturn IV booster that launched Apollo 12 in 1969 is a
tale that unfolds something like a modern day detective story, illustrating
along the way the kind of time and effort that go into identifying any thing
strange that may orbit our way.

It all started that September day a little more than a year ago, while Yeung was
reviewing images of the constellation Pisces taken at the Desert Wanderer
Observatory in El Centro, California. Suddenly, he detected a "relatively
bright, fast-mover," and thought it might be a near Earth asteroid.

The PinPoint software he was using to analyze the images -- which is designed to
detect moving objects in starfields -- identified and labeled the object J002E3,
reporting a magnitude of 16.7. Convinced it was an authentic find, Yeung sent
the astrometry in to be posted on the NEO Confirmation Page hosted by the Minor
Planet Center (MPC).

The Minor Planet Center (MPC) - which operates in the[Image]
Harvard-Smithsonian Astrophysical Observatory under the
auspices of the International Astronomical Union (IAU) -- is
responsible for the collection, checking, and dissemination
of astrometric observations and orbits for asteroids or
minor planets and comets.

Yeung's belief that it might be an asteroid was certainly reasonable. The
automated asteroid surveys had no sign of this object in previous months, and
yet there clearly was something orbiting around out there. Whatever it was it
was as bright as a 30-meter wide space rock and it seemed to be moving about as
fast as an asteroid should move.

Object J002E3, as the story goes, hit the NEO Confirmation Page within the hour.
A couple of days later, after the object had been re-observed and found again to
be orbiting the Earth, it caught the attention of scientists from various fields
within the realm of astronomy and space science -- including orbital engineers
Steve Chesley and Paul Chodas from the Jet Propulsion Laboratory (JPL);
astronomers Rob Whiteley and Carl Hergenrother, with the Lunar and Planetary
Laboratory at the University of Arizona; planetary astronomers Andy Rivkin and
Richard Binzel of the Massachusetts Institute of Technology (MIT); and space
debris specialists Kira Jorgensen and Faith Vilas from NASA's Johnson Space
Center.

During the ensuing weeks, these scientists, along with other interested
astronomers, looked at and measured the object in just about every conceivable
way, logging some 1200 observations from September 2002 to May 2003 at more than
25 observatories.

Orbital deduction

The sleuthing began at JPL with Chesley and Chodas calculating the orbit of the
object. "We didn't know what it was at the time," remembers Chesley, senior
engineer in the solar systems dynamics group in the Navigation and Mission
Design Division at the JPL. "Everybody assumed it was a spacecraft, but we
couldn't figure out what it could possibly be out that far."

Through their calculations, Chesley and Chodas - who
frequently to the asteroid database -- quickly
discovered that J002E3 was on a large 48-day orbit around
the Earth, unlike most asteroid orbits that only briefly
pass near the Earth on their orbits about the Sun. "It was
looping around Earth once every 48 days or so, coming as
close to our planet as the Moon and ranging as far away as two
lunar distances," according to Chodas, an expert in planetary motion.

"Part of the problem -- and one of the strongest arguments for J002E3 being
manmade -- is that we could see the effect of solar radiation pressure and
non-gravitational acceleration. If this were an asteroid it would not be
following this particular path," Chesley explains.

In other words, space debris and asteroids behave differently and since this
object was not exactly behaving like an asteroid, by simple deduction it must be
something manmade. As their orbital research continued, Chesley and Choda were
confident in that early hypothesis.

Within a matter of days, the object was taken off the NEO Confirmation page, the
investigation turned to manmade objects.

So what was it?

The Apollo Saturn-IV boosters (S-IVs) were, according to Chesley, "the most
obvious explanation from the start." Postulating that scientifically, however,
would require much more proof.

"When we first discovered this object, we took a look at
where it had come from [by studying the object's past
motion] and where it was going [by studying the object's
future orbit]," explains Chesley, who presented a talk on
J002E3 at the Australian Minor Planet Workshop last summer.
"With a week or two worth of data -- we could already see
that it had been captured by the Earth-Moon system in early
2002. It also became clear that it was going to be ejected
from the Earth-Moon system in early 2003."

Chesley and Chodas considered current space missions, for about a minute. "There
are very few active missions orbiting the Earth beyond the lunar distance, and
the few potential candidates were easily ruledout," offers Chesley.

>From an asteroid to manmade

With the Chesley-Chodas orbit information, Rob Whiteley and Carl Hergenrother
spent Sept. 12 and 13 taking photometric observations from the Steward
Observatory 61-inch telescope near Mt. Bigelow, north of Tucson, Arizona. They
found that J002E3 had "a very fast rotation rate and a possible pole-on
orientation," according to space debris specialist Kira Jorgensen, who had been
discussing analyzing NEOs with Whiteley when this object was found.

In fact, the spectrum of sunlight reflected from the object that Whiteley and
Hergenrother measured suggested that it had different colors than an asteroid.
"The colors were consistent with . . . titanium dioxide paint -- the type of
paint used on Apollo moon rockets 30 years ago," according to Hergenrother. That
was the first direct evidence that the newly discovered object orbiting Earth
may actually have been debris from one of the Apollo moon launches more than 30
years ago.

"Rob and Carl were able to get the initial visible measurements, and what at
that point we thought was the light curve, which showed a 63-second spin period,
and how the object varies over a certain amount of time," offers Jorgensen. "We
still are unsure if the number Whiteley obtained is the actual rotation rate.
Asteroids and human-made objects have different variations in their light
curves. This fact, however, is just evolving and infant in its studies. What we
still wanted to get was visible observations of what we believed to be the full
rotation of the object based on the spin rate calculations."

Enter Rivkin and Binzel. Using the spin rate calculations
from Whiteley, the MIT team took two nights of spectral
observations of J002E3, at multiples of 63 seconds, at the
NASA Infrared Telescope Facility (IRTF), located atop
Hawaii's Mauna Kea. The infrared data measured what they
believe was the full rotation of J002E3 on a different
wavelength.

"The spin-rate and the IRTF observations also indicated that this object was not
a 'normal' asteroid, the team wrote on a poster * presented at the Division for
Planetary Sciences meeting of the American Astronomical Society meeting held in
August. Observations from the Small Main-Belt Asteroid Spectroscopic Survey
(SMASS), conducted by Binzel, Rivkin, and others at MIT, revealed that the shape
and slop of J002E3 did not match any of the so-called "regular" asteroids.

Past that, Rivkin and Binzel's IRTF data also correlated well with -- white
titanium dioxide paint.

Awash in white paint

Meanwhile at JSC, Jorgensen had been conducting materials analyses and was soon
comparing Rivkin's and Binzel's infrared data with the infrared data on
spacecraft white paint available in NASA's laboratory.

The IRTF observations, she found, compared similarly with
laboratory samples of flown spacecraft materials.
"The absorption features in the infrared matched very well
with laboratory white paint, so we figured either the
asteroid is covered in white paint -- the likelihood of
which is very slim, or it's part of a spacecraft," she
explains. "That's how we were able to say that it's
definitely manmade."

Around the same time at JPL, Chesley and Chodas continued unraveling more of
J002E3's orbital history by conducting a number of computer simulations of the
object's trajectory. "Once we had enough data, we realized that it was just
passing through the Earth-Moon system in 2002 and 2003 -- this was a temporary
capture, and then it was going on its way," Chesley says.

They also traced the motion of J002E3 backwards in time to find out where it had
been. "We found out that it had been captured at some time in the early 1970s
and was ejected from the Earth-Moon system in 1971," says Chesley. "That was an
important clue pointing to Apollo." In other words, that orbital data indicated
that it could be a piece of debris from a rocket launched back in the late
1960s, early 1970.

Apollo 14, as history shows, launched in January 1971, and according to Chodas'
calculation J002E3 broke out of Earth orbit in March 1971. There was only one
problem with that hypothesis: NASA had accounted for all of the major pieces of
that particular spacecraft.

"The Apollo missions were launching at that time, but we knew exactly where the
stages from those missions were - at least most of them," says Chesley. "Apollos
8 through 17 had sent their Saturn IV boosters (S-IVB) out past Earth orbit and
Apollo 13 through 17 had confirmed that their upper stages had hit the Moon. So
we knew it couldn't be one of those, and Apollos 8 through 11 were confirmed to
go into orbit about the Sun, escaping the Earth-Moon system before late 1969.
That left Apollo 12."

Back at JSC, Jorgensen had created a model of the Apollo rocket body for
additional comparisons. "I took the same materials that went into the Apollo 12
rocket body and made a model cylinder that was of the same dimensions and
painted the same as Apollo had been, to match the two as best as I could," she
explains.

Within a couple of weeks, her comparisons were complete. The observations of
J002E3 showed a "strong correlation" of absorption features to a combination of
human-made materials including mostly white paint, black paint, and aluminum.

Jorgensen then went on to validate the IRTF observations of J002E3 with
observations at the Air Force Maui Optical and Supercomputing site (AMOS), as
well as comparing both sets of observations with previous data on spacecraft
launched in 1965 and in 1981. "The comparisons of the visible and the
near-infrared observations of J002E3 taken from IRTF and AMOS matched well with
the observations of a rocket body launched in 1965 and not those of one launched
in 1981," says Jorgensen. "This may indicate that the two objects, the 1965
rocket body and J002E3, have spent similar time in the space environment
[although] they are not in the same trajectory."

Apollo 12, where are you?

When Apollo 12 launched in November 1969, the mission team programmed the S-IVB
to go into orbit around the Sun, but an error occurred during the maneuver. The
crew had jettisoned the rocket body on 15 November 1969 when it was almost out
of fuel. Once the astronauts were safely on their way, ground controllers
ignited the S-IVB's engine to send it into a Sun-centered orbit, but the burn,
for whatever reasons, went on too long and instead of circling the Sun the third
stage entered a barely stable orbit around Earth and Moon. In essence, says
Chesley, "(I)t didn't get the right kick from the Moon, so that thing was lost."
Until a year ago last September, that is.

After the failed injection in 1969, Apollo 12's S-IVB "limped" around the
Earth-Moon system for a year and a half, Chesley adds. "Eventually it was kicked
out in early 1971. Then, for the next 30 years or so, it circulated around the
Sun in an orbit very much like the Earth, until last year when it lapped the
Earth and was captured again. It didn't stay for long this time. After six
rotations in fact the debris was on its way out of Earth orbit last summer. "It
is a little hard to say exactly at what point it 'escaped' since it left the
Earth-Moon vicinity over a period of months," Chelsey explains.

Further orbital research revealed the Apollo 12 S-IVB rocket body was last seen
in an orbit "almost identical to the one in which J002E3 was when Bill Yeung had
found it," adds Chesley. "The energy is the same and everything was right for
J002E3 to be Apollo 12."

By late last Fall, all the data -- the orbital information, various
observations, spectral data, and model comparisons -- were pointing to object
J002E3 being Apollo 12. But the team still didn't have the 'smoking gun' proof
it needed to say unequivocally that it definitely was/is Apollo 12. So,
officially, they concluded: J002E3 is "a human-made object from an Apollo rocket
upper stage, most likely Apollo 12."

That was good enough for some media, as headlines turned belief into fact,
reporting that the 'asteroid' was Apollo 12 debris.

"There's no question that it is some kind of artificial object," reiterates
Chesley. "The other question -- is it Apollo 12's third stage -- we can't think
of any other explanation. But, we also can't be sure. The problem is that we
can't find an orbit that allows J002E3 to pass near the Moon in November 1969,
and, thus, we cannot tie the two objects directly together by a single
trajectory," he explains. "We think we know why: we don't know very well what
solar radiation pressure is doing to the orbit."

First known case of temporary satellite capture

In all likelihood J002E3 is probably the Apollo 12 rocket body, but no matter
what it turns out to be, this much is certain: J002E3 is the first known case of
temporary satellite capture for Earth. Such events are "well documented for
Jupiter, with comets," says Chesley. But for terra firma, the event was novel.

So, will Earth 'capture' the Apollo 12 rocket body again?

"We don't know what the future holds," Chesley says
matter-of-factly. Currently, the rocket body is following an
anarchistic path. "This thing is really a wanderer now in
interplanetary space," he continues. "Once it gets tangled
up in the Earth-Moon system, it follows this chaotic
wandering trajectory, sweeping out essentially into large
volumes of space, and moving so slowly that it could at
some point in the future hit the Earth."

That may sound a lot worse than meant. You see, if that piece of Apollo 12 does
come back around on an impact trajectory for Earth, it really won't present much
danger.

"Although pieces of debris actually do reenter often, this particular Apollo 12
debris is not really an issue," says Jorgensen. Usually, by the time any pieces
of space debris come back in, there's not much left, she says. "Also, NASA does
do reentry assessments on spacecraft that have been launched now that they
realize space debris could pose a problem, so if it's going to come back in,
they know what kind of pieces are going to survive. The main thing to remember
is that 70% of the Earth is covered in water. The chances of it landing on land
are slim to begin with."

Chesley agrees: "Compared to asteroids which have one in a million kind of
impact probabilities, even the dangerous ones -- J002E3 has a very high
probability of impact over say the next 1000 years either into the Earth or
Moon," he elaborates. "Now, that's over thousands of years, and we don't even
know the next time it's going to re-visit the Earth. We can see that it will not
get captured at the next opportunity (when it next laps Earth), but we cannot be
so sure about the second opportunity, about 40 years from now."

Still, even if the Apollo 12 rocket body did come back on a collision course
with Earth, it probably wouldn't even make a splash - or dent. "The re-entry
would be less exciting, and less substantial than SkyLab," says Chesley, which
re-entered over Australia in the summer of 1979, raining some parts onto the
ocean's surface. "This debris would burn up on entry and there would be no real
impact," he adds. "There might be a big lightshow and there might be some pieces
of the hardware that might survive the fall, but that would be about it. Also,
it's more likely, much more likely to hit the Moon than the Earth."

The team still has to define absolutely, unequivocally that this object is the
third stage of the Apollo rocket -- and they plan on seeing this project through
to the very end. "There is work still to do," confirms Chesley. "We want to
definitively link this observed object with the object that was observed in 1971
and with Apollo 12 in 1969. We got as much observable data as we could when we
could see it [before it was ejected out into interplanetary space], and the
research is ongoing. It's just not going very fast right now. We have other
missions [but] when the decks get cleared, we're going to get after this again.
And, in a perfect world, we'll be able to make that connection definitive with
some more effort."

Once their work is complete, the team plans on documenting all the research in a
journal.

Citations

1. From advertising for Armageddon, the movie, Touchstone Pictures, July 1998

2. K. Jorgensen, et al., "Observations of J002E3: Possible Discovery of an
Apollo Rocket Body," International Astronomy Union, Division of Planetary
Sciences annual meeting, Monterey, California, 2003.
Received on Fri 31 Oct 2003 11:22:02 AM PST