In early
March 2008, the European Space Agency launched a new spacecraft called the
Automated Transfer Vehicle (ATV). ATV is a bigger version of the Russian
Progress, a re-supply ship for the International Space Station (ISS). ATV had a
perfect launch and docked to ISS as planned. After delivering supplies, the
craft was used as crew quarters, and at one point helped push ISS out of the way
of a dangerous piece of orbital debris. On September 5, 2008, it was finally
time to call an end to the mission and the ATV was undocked from the ISS, ready
to enter Earth's atmosphere over the South Pacific Ocean. Lacking a heat shield
to save weight, the craft will break up on reentry in a spectacular fireball.
Our team
came in the picture relatively late in the game. It turned out that we were not
the only ones who were fascinated by the fact that the 13-ton ATV would enter
in a controlled manner with a speed of 4.7 miles (7.6 kilometers) per second.
If we could use guidance from the ATV Control Center for latest trajectory
updates, we thought it would be possible to position two research aircraft
alongside the shallow entry trajectory and observe the breakup process in
detail. There is no way to do this for natural fireballs, which appear at
random in the sky and at unknown times. Fragmentation is the single most
important phenomenon that determines the physical conditions in natural
meteors.
ESA was
supportive of our proposed mission. A documentation of the breakup process
could help validate the models built to study how that fragmentation evolves in
a series of disruptions of major components. At reentry into the atmosphere,
ATV would execute one final experiment before the mission
completion. Our experience with meteor spectroscopy carried the promise of
perhaps being able to identify some of the fragments from their radiation
signatures. The ATV-1 "Jules Verne" Multi-Instrument Aircraft
Campaign was born.
A workshop
was organized at NASA Ames Research Center to discuss how best to observe the
ATV reentry, bringing observers and ATV mission managers together. It was
decided to postpone the reentry by three weeks so that the reentry would happen
at nighttime for best viewing conditions.
As in
earlier multi-aircraft
(MAC) missions, NASA Ames took the lead in organizing the effort. Two
aircraft will participate in this campaign. One is NASA's DC-8 Airborne
Laboratory, operated by the University of North Dakota (NSERC) and NASA Dryden Flight Research Center from the Dryden Aircraft Operations Center in Palmdale. The
other aircraft is a privately owned Gulfstream V, operated by H211 LLC at NASA Ames Research Center. Together they make it possible to triangulate the important
fragmentation events and measure their altitude in the atmosphere.
A large
team of researchers from ESA, NASA, universities and private organizations will
join in the mission, including a team from NASA's Orbital Debris Office at NASA
Johnson Space Flight Center. ESA project manager Dr. Jason Hatton has organized
the ESA effort, while program manager Dave Jordan of NASA Ames Research Center has coordinated the NASA effort. The logistics for some 36 researchers are
coordinated by the SETI Institute. SETI Institute's meteor astronomer, Dr.
Peter Jenniskens, is the mission scientist.
The reentry
is expected in the early morning of September 29. The two aircraft will leave
from NASA Ames and NASA Dryden in the evening of September 26 to a staging area
on the island of Tahiti in French Polynesia. From there, the team will depart
deeper into the south Pacific on the early morning of September 29. If all goes
to plan, the reentry will take only about 4 minutes, during which all data need
to be collected.
Observing
the ATV reentry is challenging, requiring good planning and communications with
the spacecraft operators. Past observation attempts have often been
unsuccessful due to lack of good coordination or wrong instrument settings. One
example is the reentry
of MIR, which was not observed from two chartered private aircraft back in
2001. Instead, MIR was directed to enter closer to the staging area, and only
those that stayed behind at the hotel in Fiji observed the MIR reentry.
Our efforts
are supported by the ATV Control Center in Toulouse, France. We hope to receive
last-minute updates on the reentry process to be able to position ourselves
well along the reentry path. Predictions have been made of how bright ATV will
be, just prior to breakup, and we hope that this will enable us to have our
instruments correctly configured. It is still a challenge and we hope you will
be rooting for us. This trip to Tahiti will be no honeymoon.
For more
information on the mission, please visit our mission website at: http://atv.seti.org.
advertisement
