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"6_2_2_44_4.TXT" (12088 bytes) was created on 03-24-93
MISSION WATCH STS-56
Atmospheric Laboratory for Applications and Science - 2
An Educational Publication of the National Aeronautics and Space Administration
One of the linchpins of NASA's Mission to Planet Earth is the series of
Atmospheric Laboratory for Applications and Science (ATLAS) missions to be
flown on the Space Shuttle. Mission to Planet Earth is NASA's contribution to
the United States Global Change Research Program, a unified study of the planet
and its components, from its interior to its outermost atmospheric regions. In
turn, Mission to Planet Earth is a cooperative element of the International
Geosphere/Biosphere Research Program, one of the most comprehensive scientific
undertakings of all time.
The primary goal of the ATLAS program is to help scientists
characterize the chemical and physical components of the middle part of Earth's
atmosphere, including the effect of the Sun's energy on those components. (The
middle atmosphere or stratosphere and mesosphere contain Earth's protective
ozone layer. Chemical processes there contribute to problems such as ozone
depletion and global warming.)
Because no single space mission can provide enough information to
accomplish this goal or provide data on possible long-term changes, NASA has
planned a series of ATLAS missions. (ATLAS-1 flew between March 24 through
April 2, 1992.) Each mission will carry a core of seven instruments designed to
gather data under a variety of atmospheric conditions over both the Northern
and Southern Hemispheres. Some of the instruments focus primarily on
atmospheric observations while others measure solar energy. Both sets of data
are essential for proper interpretation of the conditions and processes at work
in the middle atmosphere.
ATLAS-2 Mission
The ATLAS-2 mission, planned for spring of 1993, features a core payload of six
instruments that are carried to space on a Spacelab pallet and one instrument
that is carried in two cannisters mounted to the payload bay wall. The pallet,
a U-shaped cradle, fits inside the payload bay of the Space Shuttle Discovery
like a back porch. As a mounting platform, the pallet exposes instruments
directly to the conditions of outer space. Normally, the instruments will be
operated by radio control from the ground, but crewmembers may also operate the
instruments from within the orbiter's cabin. Attached to the pallet in the bay
is the Spacelab igloo. The igloo is a white cannister that houses Spacelab
subsystems, pumps, and power boxes to provide the science equipment with power,
communication links, and environmental control.
Liftoff of the eight day mission is planned for nighttime to make
sunrise observations at high northern latitudes. NASA managers will decide
during the mission if an extra day can be flown for additional science
observations.
ATLAS-2 Instruments
The Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument will survey
concentrations of trace molecules by measuring absorption of solar infrared
radiation. This instrument will help scientists determine what chemicals are
present in the middle atmosphere, what their concentrations are, where they are
located, and what chemical reactions they influence.
The Millimeter-wave Atmospheric Sounder (MAS) will also study
atmospheric constituents. MAS will measure ozone concentrations, temperatures,
water vapors and chlorine monoxide in the middle atmosphere. Chlorine monoxide
is a key trace molecule involved in the destruction of ozone.
Two instruments, the Solar Spectrum Measurement (SOLSPEC) and the Solar
Ultraviolet Spectral Irradiance Monitor (SUSIM) will characterize the solar
radiation that drives chemical reactions in the middle atmosphere. The SUSIM
will only measure ultraviolet radiation, but will cover a broader range of
ultraviolet radiation (120-400 NM) than will the SOLSPEC instrument. (A
nanometer is a metric unit equal to one-billionth of a meter. The SOLSPEC
instrument's range of 180 to 3,200 nanometers covers the electromagnetic
spectrum from ultraviolet to infrared radiation.) Both instruments, when flown
over many missions, will yield long-term records of solar radiation and its
variations.
The Shuttle Solar Backscatter Ultraviolet (SSBUV) instrument measures
both solar ultra-violet output and stratospheric ozone. This instrument has
flown previously on four other Space Shuttle missions.
Two other ATLAS instruments measure the total solar irradiance. The
Active Cavity Radiometer Irradiance Monitor (ACRIM) and the Measurement of
Solar Constant (SOLCON) seek to measure the total amount of energy the Sun
delivers to the Earth. This amount is referred to as the solar constant,
although it varies by a small amount from year to year. The variance in the
solar constant is significant because small changes in incoming energy can have
dramatic effects on the climate. By measuring incoming energy above the
atmosphere, scientists can get more precise data.
In addition to taking measurements, the instruments on this mission are
invaluable for calibrating similar instruments on scientific satellites. The
longer a satellite operates in space, the greater is the chance that
high-energy radiation or other harsh conditions can damage the hardware and
skew the data gathered. Comparison of the ATLAS data with that of free-flying
satellites can help scientists recalibrate their instruments on the satellites
and ensure their long term accuracy. In particular, ATLAS-2 will underfly the
Upper Atmosphere Research Satellite (UARS) to enhance its data.
Unique Science Opportunities
Measurements taken by ATLAS-2 are particularly crucial in light of recent
atmospheric conditions. Data gathered from the UARS and from an airborne
sampling mission in the Arctic indicate unprecedented levels of the chemical
chlorine monoxide at high northern latitudes during the winter of 1991-1992.
Given these high concentrations, atmospheric models suggest that, under
appropriate meteorological conditions, significant ozone depletion over the
Arctic is possible. (The ozone layer serves as a filter that blocks harmful
ultraviolet radiation from the Sun. When ozone amounts decrease, more
ultraviolet radiation can reach Earth's surface and damage living things.)
Chlorine monoxide is a key compound in a cyclic process where small
amounts of chlorine may efficiently destroy much larger amounts of ozone in the
stratosphere. Sunrise is the best time to measure the concentration of several
stratospheric molecules. Since these molecules form at night and are destroyed
during the day, the concentration is largest at sunrise.
Other Mission Objectives
On flight day 3, the crew will deploy the Spartan Solar Wind Physics
Experiment. The Spartan is a free- flying platform that is deployed by the
orbiter's Remote Manipulator System (RMS) for independent operations. Two
instruments onboard Spartan will gather data about the corona, the outer most
layer of the Sun, and the acceleration of the solar wind (charged particle
streams emanating from the Sun) in a variety of locations in the Sun's corona.
The RMS will retrieve Spartan after about 40 hours of operation in space.
Other mission activities include biological and medical experiments,
radiation studies, materials processing experiments, and contact with amateur
radio operators through Shuttle Amateur Radio Experiment (SAREX).
In their continuing support of education, the crewmembers will
videotape a variety of preplanned scenes on living in space to be used for an
elementary level educational videotape. The tape will be available to teachers
through the NASA Teacher Resource Center network later in the year.
STS-56 Quick Facts
Crew: Kenneth D. Cameron (COL, USMC) - Commander
Stephen S. Oswald - Pilot
Michael Foale (Ph.D.) - Mission Specialist
Kenneth D. Cockrell - Mission Specialist
Ellen Ochoa (Ph.D.) - Mission Specialist
Vehicle: OV-103, Discovery Mission Duration: 8+1 days
Orbital Inclination: 57 degrees Orbital Altitude: 296 km
Primary Payload
and Experiments:
ATLAS-2 Atmospheric Laboratory for Applications and Science
SSBUV/A-02 Shuttle Solar Backscatter Ultraviolet experiment
SPTN-201 Shuttle Pointed Autonomous Research Tool for Astronomy
CMIX Commercial Materials Dispersions Apparatus Assembly
PARE Physiological and Anatomical Rodent Experiment
STL Space Tissue Loss
CREAM Cosmic Ray Effects and Activation Monitor
SUVE Solar Ultraviolet Experiment
RME III Radiation Monitoring Experiment III
HERCULES Hand-held, Earth-oriented, Real-time, Cooperative,
User-friendly, Location targeting, and Environmental
System
SAREX Shuttle Amateur Radio Experiment
Educational Activities: Videotaping for an elementary level program on living
in space.
Classroom Activities and Questions
1. The entire progress of the mission from launch to landing can be observed
on television if your school has a satellite dish. Direct the dish to the
SATCOM F2R satellite at 72 degrees west longitude. Tune in to NASA Select,
transponder 13, 3960 megahertz. If your school does not have a satellite dish
but does have a cable television hookup, call your local cable company and
request that they receive NASA Select and either distribute it on one of their
channels or tape it for your use. Check local news services for updates on
Discovery's liftoff or call the NASA Kennedy Space Center at 407-867-2525 for a
recorded message.
2. Collect current newspaper and magazine articles on environmental problems
relating to Earth's atmosphere. Contact NASA SPACELINK (see below) for
additional information.
3. What are some of the consequences of atmospheric ozone depletion and global
warming? What are the sources of chemicals that trigger ozone depletion?
4. Contact the American Radio Relay League for the name of a local amateur
radio operator who might be willing to provide a SAREX demonstration for your
classroom. The league coordinates educational activities related to the
experiment, which is expected to fly again on several future Shuttle missions.
American Radio Relay League
225 Main Street
Newington, CT 06111
References and Resources
% To request copies of the publications below, write:
NASA Education Division
Code FET
NASA Headquarters
Washington, DC 20546
% Publication text is also available from NASA SPACELINK. See references and
resources section below.
NASA (1992), The Atmosphere Below (videotape), Liftoff to Learning series.
Comes with a video resource guide for the teacher. NASA Education Division,
Washington, D.C.
NASA (1992), ATLAS Educator Slide Set, NASA Education Division, Washington,
D.C.
NASA (1991), Earth's Mysterious Atmosphere - ATLAS 1 Teacher's Guide with
Activities, EP-282/11-91,
NASA Education Division, Washington, D.C.
NASA (1989), The Upper Atmosphere, A Program to Study Global Ozone Change,
3/89:20K.
NASA SPACELINK provides information about current and historic NASA programs,
lesson plans, the text from previous Mission Watch and Mission Highlights fact
sheets. Anyone with a personal computer, modem, communications software, and a
long distance telephone line can communicate directly with NASA SPACELINK. Use
your computer to dial 205-895-0028 (8 data bits, no parity, and 1 stop bit).
Mission Patch for STS-56
The STS-56 patch is a pictorial representation of the STS-56/ATLAS-2 mission as
seen from the crew's viewpoint. The payload bay is depicted with the ATLAS-2
pallet, Shuttle Solar Backscatter Ultra Violet (SSBUV) experiment, and Spartan,
the primary scientific payloads on the flight. ATLAS-2 is a "Mission To Planet
Earth," so the Earth is featured prominently. The mission's two primary areas
of study are the atmosphere and the Sun. To highlight this, the Earth's
atmosphere is depicted as a stylized visible spectrum and the sunrise is
depicted with an enlarged two-colored corona. The commander's and pilot's
names are written in the Earth field and the names of the mission specialists
are in the space background.