[meteorite-list] Space Oddity: The Mystery of 2013 QW1

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 20 Sep 2013 11:14:01 -0700 (PDT)
Message-ID: <201309201814.r8KIE14Z008107_at_zagami.jpl.nasa.gov>

http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Space_oddity_the_mystery_of_2013_QW1

Space oddity: the mystery of 2013 QW1
European Space Agency
19 September 2013

Last month, ESA's near-Earth asteroid coordination centre
triggered a series of European observations that confirmed an
unknown object was, in fact, of human origin. The confirmation was
the Centre's second such success in recent months and demonstrates
the effectiveness of the Agency's asteroid-monitoring activities.

On 23 August, a rather unusual object was spotted in the sky by
the US PanSTARRS asteroid survey and provisionally named 2013 QW1.

The suspected near-Earth object (NEO) was moving in an Earth-centred
orbit, leading astronomers to ask: was it natural or artificial?

If artificial, it would not be the first time that an
asteroid-hunting survey had rediscovered a lost rocket stage
wandering in space close to the edge of our planet's gravitational
reach.

Another object found in 2002

For example, when the third stage of the Apollo 12 mission failed
to crash on the Moon as planned (NASA used such impacts to
generate "Moonquakes" that could be studied by lunar seismographs
to gain information on the Moon's interior), its subsequent
orbital evolution was alternatively dominated by the attraction of
the Sun and Earth.

The object was eventually rediscovered in 2002 as a temporary
satellite of Earth, and its manmade origin was revealed by
analysing the light reflected by the rocket body, which did not
resemble that of an asteroid but rather revealed the
titanium-enriched white paint used at that time for the Apollo
rockets.

However, for the mysterious 2013 QW1, things were not that simple,
and further observations were needed to determine whether it was
artificial or natural.

That's when ESA's NEO Coordination Centre became involved, sending
an alert to a number of collaborating observatories in Europe to
trigger additional observations that might help to confirm the
object's identity.

European astronomers up to the challenge

The challenge was taken up by a team led by Elisabetta Dotto at
INAF-Osservatorio di Roma, and Davide Perna and Maria Antonietta
Barucci at the Observatoire de Paris, Meudon, who obtained time on
the Italian Telescopio Nazionale Galileo to capture light
reflected from the object.

"It was a bit of a challenge, because the object was moving fast
with respect to a typical suspected NEO," said Dr Perna.

"But despite the difficulties, observations were made with an
instrument called DOLORES, for 'Device Optimized for the LOw
RESolution', which allowed us to obtain the object's spectrum."

The result was a spectrum that does not resemble any asteroid.
Instead, it bore strong similarities with the spectra of
previously observed space junk such as discarded rocket stages,
abandoned boosters or defunct satellites.

These measurements provided convincing evidence of the artificial
nature of 2013 QW1 - it is possibly a booster stage - and
supported it being removed from ESA's NEO catalogue and included,
under the name 2010-050B, in the Minor Planet Center's Distant
Artificial Satellite Observations list
<http://www.minorplanetcenter.net/iau/DASO/000000/DASO_000486.txt>.

ESA's coordinating role

The event highlights the coordination role that ESA's new NEO
Coordination Centre is playing in addition to its primary function
of providing information on all known NEOs, including their
orbits, impact risk and close approaches to Earth.

"The observations by European astronomers coordinated by ESA
demonstrated a very quick reaction in getting high-quality data
that conclusively identified the object as artificial, and hence
no threat," says Detlef Koschny, responsible for NEO activities at
ESA's Space Situational Awareness programme office.

"Our Centre has again shown it is serving as a focal point for
coordinating observations which are vital for the European and
international community involved in asteroid science, impact
monitoring and mitigation."
Received on Fri 20 Sep 2013 02:14:01 PM PDT