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The Leonids are the great natural fireworks display of all time. Every man, woman and child can observe and enjoy a meteor shower. Every fireball, faint meteor and persistent train yields information about life on earth, about our atmosphere and about our solar system. This is the final tale of my 2002 Leonid MAC mission adventure. The 2002 Leonids were stunning from 39,000 feet. To state that we were above cloud nine would be an understatement!
An airborne mission needs a pilot. Our NASA DC-8 Airborne Laboratory was piloted by astronaut Gordon Fullerton. Fullerton logged 382 hours in space flight and was an astronaut from 1969 until 1986 when he completed a 30-year career with the U.S.Air Force and retired as a colonel. Fullerton served on the support crews for the Apollo 14, 15, 16, and 17 lunar missions. In 1977, Fullerton was assigned to one of the two two-man flight crews that piloted the Space Shuttle prototype Enterprise during the Approach and Landing Test Program at Dryden. His assignments now include a variety of flight research and support activities piloting NASA's B-52 launch aircraft, the 747 Shuttle Carrier Aircraft (SCA), and other multi-engine and high performance aircraft. Fullerton was the pilot on the eight-day STS-3 Space Shuttle orbital flight test mission Mar. 22-30, 1982. He was commander of the STS-51F Spacelab 2 mission, launched on July 29, 1985. This mission, with the orbiter Challenger, was the first pallet-only Spacelab mission and the first to operate the Spacelab Instrument Pointing System (IPS). He and three other pilots manned the flight deck of our DC-8 airborne laboratory for the 7 day mission.
We took off at 02h UT and the radiant was already above the horizon. We could see Leonids immediately, but there were alot of clouds. When we cleared the clouds the seven members of the 2002 Intensified Meteor Counting Unit — the IMCU — donned their observing i-goggles and started counting meteors by right-clicking for sporadics and left-clicking for Leonids. We had a full night of meteor counting practice on the night we flew from Nebraska to Spain. On that night from 2:00 UT to 7:00 UT, our total meteor count was 258 Leonids and 313 sporadics, including Taurids. We saw more meteors than this in a few minutes on storm night.
We each plugged our meteor counting computer mouse with a machine readable identification number into a serial port corresponding to one of the eight intensified cameras: three on the right side of the aircraft, four on the left and one all-sky camera aimed at the zenith. One member of our team observed the meteors and determined their brightness to establish the r-value — the distribution of meteor magnitudes. On the flight to Spain, we identified the camera field of view we saw in our i-goggles, and calculated the size of this field by plotting the star fields we saw in our goggles. We also counted meteors that night to establish the baseline rate of sporadic meteors, and to get our observing program organized. We were responsible for alerting the instrument operators to any fireballs or persistent trains in our field of view and had a chart identifying where our camera was pointing to assist in communicating the information. Luckily we spotted several persistent trains and were able to get the information to the other researchers in time for action.
But on Leonid night we counted meteors — lots and lots of meteors. By dawn, our team had counted 18,600 meteors. I personally counted 3,730 Leonids and 98 sporadics, many of which were slow bright Taurids. I unplugged my meteor counting mouse whenever 20 percent of my field of view was obscured by land, clouds or moonlight reflecting off the wings of the DC-8. My highest one minute counts came at 04:09 UT during the first shower when I counted 60 Leonids and one sporadic. My highest one minute count for the second peak came at 10:50 UT when I counted 75 Leonids and 1 sporadic meteor. This is no surprise — these are the exact moments of the peaks for both storms. For the 15 minutes before and 15 minutes after the first peak I counted a total of 920 Leonids and 19 sporadic meteors. For the 15 minutes before and 15 minutes after the second peak I counted a total of 1063 Leonids and 9 sporadic meteors. That is more than half of all the meteors I counted in over 6 hours of counting! The Leonid rate stayed quite high — we counted about 100 Leonids per hour during all the hours between the two peaks.
Rather than giving a huge list of my one minute counts and zenithal hourly rates, which use many variables to derive and take some explaining to understand, please refer to the Leonid MAC website for the most current official team count statistics. Here are the first numbers: http://leonid.arc.nasa.gov/index.html
Our counts are higher than those of ground-based observers because we used intensified cameras which allowed us to see many fainter meteors — those that would have been washed out by moonlight, and any dust and moisture in the air. Regardless, our counts and the exponential rise and fall in rates match nicely with the International Meteor Organization counts shown alongside our own first results in the above chart. It was alot of fun to be part of such an exciting mission again!
We had an extra bonus on our flight over the polar regions — the aurora borealis, or northern lights! Dr. Peter Jeniskens wrote "A curtain of aurora over the northern horizon emitted pulsing waves of light into the sky, penetrated by a rain of meteors." The intensified view through my i-goggles was breathtaking and lasted for well over an hour, with columns, sheets, swirls and rays of shimmering light filling my field of view, punctuated by dozens of meteors per minute. I rushed to the window to see the aurora and meteor storm for myself without the aid of goggles or cameras. The pale white glimmering sheet with subtle hints of red and green was stunning. What a fitting end to the 2002 Multi-instrument Aircraft Campaign!