STS-67 Day 5 Highlights
Back to STS-67 Flight Day 04 Highlights:
- On Tuesday, March 7, 1995 at 9 a.m. CST, STS-67 MCC Status Report # 10
reports: Earlier this morning, flight controllers did some
troubleshooting after a circuit breaker tripped, cutting power to a
portion of the Commercial Materials Dispersion Apparatus
Instrumentation Technology Associates Experiment (CMIX). When Lawrence
reset the circuit breaker on the middeck experiment and repowered the
heater controller, ground controllers noticed a short. Lawrence
subsequently was directed to turn off the heater, which maintained a
slightly higher temperature (20 degrees Centigrade vs. 4 degrees
Centigrade) for a portion of the Commercial Refrigerator Incubator
Module (CRIM). three of the four experiment trays already had been
chemically fixed, and scientists won't know until after landing what
affect the heater loss will have on the samples. The CMIX/CRIM
experiments which require no heat, referred to as the "cold"
experiments, were unaffected by this event.
- Other activities performed by the Blue Team include a successful
alignment of the inertial measurement units which was performed by
Lawrence, and a 12-hour water dump using the flash evaporator system
was initiated this morning.
- On Tuesday, March 7, 1995 at 6 a.m. CST, STS-67 Payload Status Report # 11
reports: (5/5:22 MET) Crew members for the second Astro
Observatory (Astro-2) mission spent a busy fifth night in space,
working with three unique ultraviolet telescopes to help scientists on
Earth learn more about the universe. Pilot William Gregory and
Mission Specialist Wendy Lawrence maneuvered the Space Shuttle
Endeavour into different orbital positions as Payload Commander Tammy
Jernigan, Mission Specialist John Grunsfeld, and Payload Specialists
Ronald Parise and Sam Durrance aligned the telescopes nestled in
Endeavour's payload bay.
- From the Marshall Space Flight Center in Huntsville, Ala., the
science teams for the Hopkins Ultraviolet Telescope (HUT),
Ultraviolet Imaging Telescope (UIT) and the
Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) watched
video from the HUT target acquisition camera onboard the Shuttle while
they calibrated their instruments. During this calibration period, in
which HUT was pointed at a hot dwarf star in the constellation Auriga,
scientists were able to check the data from their telescopes against
- Three types of galaxies were observed by the Astro-2 telescopes
overnight to help scientists understand more about the formation of
stars in a galaxy system. UIT used both of its onboard cameras to
make images of these galaxies in both the long and short wavelength
ranges. A prime target for UIT was a globular cluster in the
constellation Carina. This cluster is a massive spherical
concentration of stars containing up to several hundred thousand
stars. This group of stars, which is extremely old, provides
astronomers with information about the latter part of the evolution of
- HUT and WUPPE observed a massive blue star called Psi Persei, a
luminous star that spins rapidly and has outer layers that show
evidence of being peeled off by their stellar winds. Previous
observations have suggested that these gas-laden winds are strongest
near the equator of these rapidly spinning stars. Psi Persei has an
unusual ultraviolet spectrum that may be caused by a shell of gas
around the star, possibly the remains of the layer that has been
peeled off the star. Scientists hope to accurately determine this
type of star's temperature (in order to analyze its atmospheric
emission), search for stellar winds and study absorption in the
interstellar medium, gas and dust between these stars.
- HUT and WUPPE also used a bright star much like a flashlight to
illuminate the gas and dust between stars. This type of observation
will help scientists understand more about the chemical composition
and physical nature of the dust and gas between stars in our Milky Way
galaxy. During the first Astro mission, astronomers learned that some
parts of our galaxy seem to have dust grains that resemble tiny hockey
pucks, while other parts seem to have a mixture of several sizes,
shapes and kinds of dust grains. During Astro- 2, WUPPE Principal
Investigator Dr. Arthur Code hopes to determine whether different
conditions in some parts of the galaxy affect the formation of these
- The science teams for HUT, UIT and WUPPE observed video from the
HUT target acquisition camera as their instruments measured a
supernova remnant known as Cygnus Loop. This supernova remnant, in
the constellation Cygnus, the Swan, is from a star that exploded many
years ago. Both cameras of the UIT imaged the supernova remnant in
both the short ultraviolet and long ultraviolet ranges. Guest
Investigator Dr. John Raymond is using HUT to obtain information about
shock waves the physics of collisionless shocks, the destruction
of grains in shocked gas, instabilities behind radiative shocks and
shock wave parameters.
- The Astro-2 ultraviolet telescopes also observed a Wolf-Rayet star,
thought to represent one of the final phases in the evolution of
massive O and B stars, which have between 100,000 and 1,000,000 times
the radiance of the sun, with temperatures up to 100 times greater.
One of the most unusual features of this type of star is that it has
almost no dark, or absorption, lines in its spectrum, only bright,
broad emission lines.
- The three Astro-2 ultraviolet telescopes also gathered information
about spiral galaxies during the night. Guest Investigator Dr. Wendy
Freedman is using the UIT to image several large, face-on (top or
bottom view) galaxies in the far- and near-ultraviolet spectrum.
Freedman will combine UIT images gathered on both the Astro-1 and
Astro-2 missions to create a digital atlas of spiral galaxies. Data
gathered about galaxies will also be used to study the similarities
between the types of galaxies viewed by the Hubble Space Telescope in
the visible and ultraviolet spectrums.
- On Tuesday, March 7, 1995 at 4 p.m. CST, STS-67 MCC Status Report # 11
reports: Commander Oswald transferred data from the ground to the
orbiting Middeck Active Control Experiment via a high-speed
air-to-ground link as Gregory took care of orienting the shuttle for
its Astro-2 observations and performed housekeeping duties.Grunsfeld
and Parise each were scheduled for some off-duty time.
- On Tuesday, March 7, 1995 at 6 p.m. CST, STS-67 Payload Status Report # 12
reports: (5/17:22 MET) The Wisconsin Ultraviolet Photo-Polarimeter
Experiment (WUPPE) and Hopkins Ultraviolet Telescope (HUT) viewed
Wolf-Rayet star HD 191765 twice this morning, completing a set of
observations begun last night. "This is a fairly faint star, so we
are observing it four times to get all the information we need,"
explained Guest Investigator Dr. Regina Schulte-Ladbeck of the
University of Pittsburgh. "We know this star's polarization varies
over time, so we put all the observations within a 12-hour period in
order to make them as nearly the same as possible." Schulte-Ladbeck
noted that the first observation showed very high ultraviolet
polarization, and she feels confident that all four data sets will
yield the same result.
- Wolf-Rayet stars are thought to be a final life stage of very hot,
massive and luminous stars. Powerful stellar winds cause matter to be
lost from them, making them less and less massive over time.
Schulte-Ladbeck is studying the mechanism of mass loss from the stars,
as mass is returned to the interstellar medium and new stars are
formed. "Wolf-Rayets are depositing chemically processed matter
containing elements like carbon, nitrogen and oxygen for the next
generation of stars, so the new stars will be different," she
- This afternoon, WUPPE and HUT viewed EZ Canis Majoris, a much
brighter Wolf-Rayet which was observed for a briefer time during
Astro-1. Ultraviolet polarization studies can help astronomers
determine the shape of the material being thrown out from the star, so
they can formulate a three- dimensional "map" of its structure.
- The WUPPE instrument also focused on the bright ultraviolet star HD
25090 to illuminate the interstellar medium for their polarization
study of the dust between stars. Determining characteristics of
interstellar dust will help astronomers make allowances for the
existence of this obstructing matter when studying other objects and
to study its function as the source of new stars.
- All three telescope teams joined today's observations of two active
galaxies, thought to have supermassive black holes at their centers.
NGC 4151 is a Seyfert-1 type galaxy, which emits very bright
ultraviolet radiation. NGC 1068 is a Seyfert-2, with ultraviolet
emissions that are not as strong. "Astro-1 and Hubble Space Telescope
observations suggest there are opaque disks of cold gas around the
cores of these galaxies," said HUT team member Dr. Gerard Kriss. "It
could be that there is no difference in the two Seyfert types, except
that we're viewing Seyfert-2's from the side with the gas disk
obscuring the hot core, and we see Seyfert-1's from the top with our
view of the hot gas unobstructed. It's something like not being able
to see the hole in a donut when you look at the donut from the side."
Actually, Kriss said, NGC 4151 is in the "twilight zone" of Seyferts,
exhibiting unusual characteristics that suggest it might be tilted at
an intermediate angle to Earth.
- "NGC 4151 was five times as bright today as it was during Astro-1
observations in 1990, and there was a 10 percent increase in
brightness today over what we saw when we first observed it two days
ago," said Kriss. The galaxy is known to be extremely variable, so
Astro-2 scientists hope to view it several more times to capture it at
various levels. The multiple pointings should help Hopkins
astronomers learn more about the location, composition, density and
temperature of the gas. Astro-1 observations of NGC 1068 revealed
unanticipated evidence that gas clouds were heated by shock waves
speeding from the galaxy's core. Speaking on air-to-ground
communication loops from Spacelab Control, Kriss guided Payload
Specialist Sam Durrance in placing the telescope's view just outside
the core of NGC 1068, to look for the location of the shock-heated
- Ultraviolet Imaging Telescope (UIT) team members will search
today's photographs of irregular galaxy NGC 4449 for young stars.
Active star formation is on-going in these arms, but not in the
symmetrical distribution more common in spiral galaxies. The Hopkins
telescope focused on a supernova remnant near the galaxy's nucleus,
which has a rich store of atomic oxygen buried in a region of ionized
hydrogen. While the images should reveal details of star formation
regions, spectral measurements of the supernova remnant should show
the composition and temperature of the ionized gas.
- UIT also photographed an open cluster of hot stars, called N4.
These diffuse clusters of stars are thought to be young systems, less
than 10 million years old. UIT's wide field of view allows the camera
to make ultraviolet images of many stars at a time, so the images will
be used to identify hot binary stars pulling matter from one another,
planetary nebulae, X-ray sources, white dwarfs and other faint, hot
- Other observations today included two white dwarf stars, RE 0512
and GD153; the rapid-star formation galaxy NGC 2903; and another
portion of the Cygnus Loop supernova remnant .
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