Selected Articles from the
March 1999 Odyssey
Editor: Norm Cook
A NASA-industry team has used the results of Space
Shuttle experiments to develop a new flu drug that may decrease the length
and severity of the illness and even prevent the development of symptoms
in those exposed to the virus.
"With NASA support for space and ground-based research, we successfully
mapped the molecular structure of the influenza virus," said Dr. Larry
DeLucas, director of the Center for Macromolecular Crystallography at
the University of Alabama at Birmingham. "The mapping exposed the virus's
weaknesses in greater detail and our industrial partners were able to
develop a drug that exploits those weaknesses."
Dr. Ming Luo, a professor at the Center for Macromolecular Crystallography,
and an international team of crystallographers developed the "molecular
map" of the flu virus from space grown protein crystals. The map was used
to design drugs that block the undesirable characteristics of the virus.
"It's like trying to build a tiny key that fits into a tiny lock," said
DeLucas. "Except this lock is living, breathing, flexing, changing temperatures,
and in constant motion."
Pure, precisely ordered protein crystals of large size and uniformity
are in high demand by drug developers. When grown on the ground, protein
crystals often cannot be grown as large or as well-ordered as researchers
desire, obscuring vital pathways to a better understanding of disease.
The "frequent flyers" of the space program, protein crystal growth experiments
are aboard nearly every Space Shuttle mission, helping researchers unlock
the secrets of how to stop infection and disease on Earth.
Influenza protein crystals flown aboard the Space Shuttle in May 1996
were used to confirm earlier studies and to determine the effectiveness
of potential drugs on the flu virus protein.
"By analyzing space-grown crystals of the influenza virus, we were able
to get a clearer picture of the virus's structure," said DeLucas. "NASA's
support for this research project probably saved considerable time needed
to develop this new drug."
The flu virus infects 20 to 40 million people in the United States each
year, even with vaccines, and thousands are at risk of dying from its
The new drug, part of a new class of medicines called neuraminidase
inhibitors, was developed in a partnership between NASA and the Center
for Macromolecular Crystallography. The new compound was synthesized by
BioCryst Pharmaceuticals in Birmingham, AL, and is under development by
The R.W. Johnson Pharmaceutical Research Institute, Raritan, NJ, a Johnson
& Johnson Company.
Sponsored by the Space Product Development Office, Microgravity Research
Program, at NASA's Marshall Space Flight Center, Huntsville, AL, DeLucas's
organization is chartered as a NASA Commercial Space Center--encouraging
private industry to benefit from space technology.
Neuraminidase inhibitors are designed to block an active site of influenza
neuraminidase, an enzyme associated with the spread of the flu. Unlike
vaccines, which have to be taken before exposure and are only specific
to certain strains of the influenza virus, a neuraminidase inhibitor may
be taken as either treatment or prevention, and is effective against a
wide variety of influenza strains.
The R.W. Johnson Pharmaceutical Research Institute is responsible for
all phases of testing the drug in humans. Before becoming available in
the United States, the drug must undergo this testing and be approved
by the Food and Drug Administration.
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Analysis of data from NASA's Lunar Prospector spacecraft
has confirmed that the Moon has a small core, supporting the theory that
the bulk of the Moon was ripped away from the early Earth when an object
the size of Mars collided with the Earth.
Scientists presented this result and other findings in a series of papers
at the 30th Lunar and Planetary Science Conference in Houston, TX. Their
data show that the lunar core contains less than four percent of the Moon's
total mass, with the probable value being two percent or slightly less.
This is very small when compared with the Earth, whose iron core contains
approximately 30 percent of the planet's mass.
"This is a critical finding in helping scientists determine how the
Earth and Moon formed," said Dr. Alan Binder of the Lunar Research Institute,
Tucson, AZ, principal investigator for Lunar Prospector.
Similarities in the mineral composition of the Earth and the Moon indicate
that they share a common origin. However, if they had simply formed form
the same cloud of rocks and dust, the Moon would have a core similar in
proportion to the Earth's. A third theory suggests that the moon was captured
fully intact by the Earth's gravity.
Based on information first gathered during the Apollo era, scientists
suggested that the Moon was formed when a Mars-sized body hit the Earth
during its earliest history. "This impact occurred after the Earth's iron
core had formed, ejecting rocky, iron-poor material from the outer shell
into orbit," Binder explained. "It was this material that collected to
form the Moon.
"Further analysis of Lunar Prospector data to refine the exact size
of the lunar core and the amounts of elements like gold, platinum, and
iridium in lunar rocks--all of which are concentrated with metallic iron--is
required," Binder added. "This will do much to pin down for good if the
ėgiant impact' model of the formation of the Moon is correct, or if the
Moon formed in a different manner."
The current data come from gravity measurements conducted by Dr. Alex
Konopliv of NASA's Jet Propulsion Laboratory, Pasadena, CA. His results
indicate that the Moon's core radius is between 140 and 280 miles (220
and 450 kilometers). This result is consistent with independent magnetic
data, evaluated by Dr. Lon Hood of the University of Arizona, Tucson,
which suggest that the core radius is between 180 and 260 miles (300 and
In other results from Lunar Prospector, Dr. Robert Lin of the University
of California at Berkeley, Dr. Mario Acuna of NASA's Goddard Space Flight
Center, Greenbelt, MD, and Hood also found that a broad section of the
southern far-side of the Moon has large localized magnetic fields in its
crust. These fields occur opposite the large Crisium, Serenitatis, and
Imbrium basins--three of the "seas" that cover much of the Moon's near
side. This result supports earlier evidence linking strong magnetized
concentrations on one side of the Moon with young, large impact basins
on the other side.
Results of efforts to map the composition of the lunar crust have surpassed
the expectations of the spectrometer team, led by Dr. William Feldman
of the Department of Energy's Los Alamos National Laboratory in New Mexico.
Data obtained are so good that the distribution of thorium has been mapped
with a resolution of 36 miles (60 kilometers). At this amount of detail,
scientists can detect individual deposits rich in thorium and related
elements. Their current observations suggest that thorium was excavated
by impacts of asteroids and comets, and then distributed around craters,
rather than being deposited by volcanic activity.
Lunar Prospector conducted its primary mapping mission at an altitude
of 63 miles (100 kilometers) for almost one year after its arrival in
lunar orbit on Jan. 11, 1998. In December and January, the spacecraft's
altitude was lowered to approximately 15 miles by 23 miles (24 kilometers
by 37 kilometers). Analyses of data from the lower-altitude observations
are expected to further improve scientific understanding of the origin,
evolution and physical resources of the Moon.
The $63 million mission is managed by NASA's Ames Research Center, Moffett
Field, CA, and was developed under NASA's Discovery Program of lower-cost,
highly focused small scientific spacecraft.
Further information about Lunar Prospector, its science data return,
and relevant charts and graphics can be found on the
project web site at the Ames Research Center.
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