Conference 7.286::space

Newsgroups: sci.space
Subject: Launch Advisory:  COBE launch delayed (Forwarded)
Date: 28 Oct 89 05:02:57 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Jim Cast
Headquarters, Washington, D.C.
 
George Diller
Kennedy Space Center, Fla.
  
    LAUNCH ADVISORY:  COBE LAUNCH DELAYED
  
     The planned November 9 launch of the Cosmic Background Explorer
(COBE) spacecraft from Vandenberg Air Force Base, Calif., has been
delayed until November 19. 
 
     In addition to a delay which occurred when the McDonnell Douglas
Delta launch support team was required on the East Coast to support a
recent Department of Defense mission, the COBE was further delayed due
to a leak in the Delta launch vehicle's second stage fuel tank shutoff
valve - a valve which must be replaced. 

Date: 9 Nov 89 00:21:59 GMT
Subject: COBE Press Kit (Forwarded).
  
                     PUBLIC AFFAIRS CONTACTS
 
                      Paula Cleggett-Haleim
            Office of Space Science and Applications
               NASA Headquarters, Washington, D.C.
                     (Phone:  202/453-1547)
 
                            Jim Cast
                     Office of Space Flight
               NASA Headquarters, Washington, D.C.
                     (Phone:  202/453-8536)
 
                     Carter Dove/Jim Elliott
           Goddard Space Flight Center, Greenbelt, Md.
                     (Phone:  301/286-5566)
 
                    George Diller/Dick Young
                   Kennedy Space Center, Fla.
                     (Phone:  407/867-2468)
 
 
 
                            CONTENTS
 
General Press Release
Cosmic Background Explorer Summary------------------------4
The Cosmic Background Explorer Mission--------------------4
    Major Mission Events----------------------------------6
    COBE Mission Phases-----------------------------------7
    Observatory/Instrument Checkout-----------------------7
    Mission Operations------------------------------------9
    Mission Lifetime--------------------------------------9
 
COBE Science----------------------------------------------9
    COBE Science Questions-------------------------------12
    Cobe Instruments-------------------------------------12
 
Launch Vehicle Preparation-------------------------------14
    Testing and Modifications----------------------------14
    Vehicle Assembly-------------------------------------14
    Launch Pad Refurbishment-----------------------------15
    Delta/COBE Launch Readiness--------------------------15
 
COBE Mission Management----------------------------------15
Science Working Group------------------------------------16
Contractors----------------------------------------------17

  
GENERAL PRESS RELEASE
 
NASA SPACECRAFT TO LOOK OUT INTO SPACE, BACK IN TIME
 
 
     NASA will launch a spacecraft on Nov. 17, 1989, to study the 
origin and dynamics of the universe, including the theory that 
the universe began about 15 billion years ago with a cataclysmic 
explosion -- the Big Bang.
 
     The Cosmic Background Explorer (COBE) spacecraft will be 
boosted into an Earth polar orbit from Vandenberg Air Force Base, 
Calif., aboard the final NASA-owned, NASA-launched Delta vehicle.
 
     By measuring the diffuse infrared radiation (cosmic 
background) that bombards Earth from every direction, COBE's 
instruments will help clarify such matters as the nature of the 
primeval explosion -- which started the expansion of the universe 
and made it uniform -- and the processes leading to the formation 
of galaxies.
 
     From its orbit 559 miles above Earth, COBE will carry out 
its cosmic search using three sophisticated instruments:  the 
Differential Microwave Radiometer (DMR), Far Infrared Absolute 
Spectrophotometer (FIRAS) and Diffuse Infrared Background 
Experiment (DIRBE).
 
     DMR will determine whether the primeval explosion was 
equally intense in all directions.  Patchy brightness in the 
cosmic microwave background would unmask the as-yet-unknown 
"seeds" that led to the formation of such large bodies as 
galaxies, clusters of galaxies, and clusters of clusters of 
galaxies.  Measurements of equal brightness in all directions 
would mean the puzzle of how these systems could have condensed 
since the Big Bang will be even more vexing than it is today.
 
     To distinguish the emissions of our own Milky Way galaxy 
from the true cosmic background radiation, DMR will measure 
radiation from space at wavelengths of 3.3, 5.7 and 9.6 
millimeters.
 
     FIRAS, covering wavelengths from 0.1 to 10 millimeters, will 
survey the sky twice during the year-long mission to determine 
the spectrum (brightness versus wavelength) of the cosmic 
background radiation from the Big Bang.
 
                              - 2 -
  
     The spectrum that would result from a simple Big Bang can be 
calculated with great accuracy.  Such a spectrum would be smooth 
and uniform and have no significant releases of energy between 
the time of the Big Bang and the formation of galaxies.  If 
FIRAS' measurements depart from the predicted spectrum, 
scientists will know that powerful energy sources existed in the 
early universe between these times.
 
     These sources may include annihilation of antimatter, matter 
falling into "black holes," decay of new kinds of elementary 
particles, explosion of supermassive objects and the turbulent 
motions that may have caused the formation of galaxies.
 
     FIRAS' sensitivity will be 100 times greater than that 
achieved so far by equivalent ground-based and balloon-borne 
instruments.  Producing a spectrum for each of 1,000 parts of the 
sky, the FIRAS data will allow scientists to measure how much 
light was radiated by the Big Bang.
 
     DIRBE will search for the diffuse glow of the universe 
beyond our galaxy in the wavelength range from 1 to 300 
micrometers.  In the final analysis, any uniform infrared 
radiation that remains will be very rich in information about the 
early universe.  One possible source would be light from 
primordial galaxies shifted into the far infrared by the 
expansion of the universe.
 
     The 5,000-pound spacecraft and its three infrared- and 
microwave-measuring instruments were designed and built for the 
Office of Space Science and Applications by NASA's Goddard Space 
Flight Center, Greenbelt, Md.  Goddard also will manage the 
launch and analyze the data returned by COBE during its 1-year 
nominal mission.
 
     Looking out into space, back in time, the COBE spacecraft 
will undertake the esoteric task of providing new insights into 
the origin and evolution of the universe.
 
                             - end -
  
               COSMIC BACKGROUND EXPLORER SUMMARY
  
MISSION:  During the 2-year mission, COBE will determine the 
spectrum of the cosmic background radiation, search for radiation 
from the very first stars and galaxies and map the cosmic 
background radiation with unprecedented accuracy.  COBE will 
study the physical conditions in the very early universe and the 
onset of organization following the Big Bang.
 
LAUNCH:  No earlier than 11/16/89, aboard a Delta 5920 ELV, from 
Space Launch Complex 2 - West, Western Space and Missile Center, 
Vandenberg Air Force Base, Calif.  Launch window is 1/2 hour 
beginning at 6:24 a.m. PST.  An Advanced Range Instrumentation 
Aircraft will cover the down-range burn of the Delta rocket.
 
ORBIT:  559-mile, sun-synchronous, near polar orbit, will circle 
the globe 14 times a day.
 
SCIENCE DATA:  Once a day, data are transmitted to Goddard Space 
Flight Center's Wallops Processing Flight Facility then forwarded 
to the COBE Science Data Center at GSFC.
 
SPACECRAFT:  With 3 solar arrays deployed, 16 feet long, 28 feet 
in diameter, weighing 5,000 lbs.
 
INSTRUMENTS:  Differential Microwave Radiometer, Diffuse Infrared 
Background Experiment and the Far Infrared Absolute 
Spectrophotometer.
 
 
NOTE:  a) Explorers are relatively small, free-flying scientific 
spacecraft.  b) COBE is the 65th Explorer mission.  c) COBE has 
the most sensitive detectors ever flown in a space mission.  d) 
COBE will use the 184th and last NASA-owned Delta.
 
 
             THE COSMIC BACKGROUND EXPLORER MISSION
 
     NASA's COBE mission will produce the most comprehensive 
observations to date of the early universe. 
 
     The wavelength band to be studied by COBE includes the 
cosmic background radiation or so-called "remnant radiation," 
believed to be the signature of the primeval cosmic explosion, 
the "Big Bang."  Current theory also holds that this band 
contains radiation characteristic of the formation of the first 
galaxies and stars.  It also might provide evidence of other 
exotic and energetic events occurring in the epochs between the 
Big Bang and the formation of galaxies. 
 
                              - 5 -
  
     COBE will carry three sophisticated, state-of-the-art 
instruments to study the background radiation:  the Differential 
Microwave Radiometer (DMR), the Far Infrared Absolute 
Spectrophotometer (FIRAS) and the Diffuse Infrared Background 
Experiment (DIRBE).
 
     Because the diffuse cosmic background radiation itself is 
extremely faint, the COBE spacecraft and its three experiments 
have been designed to allow observations at unprecedented 
sensitivities.  To that end, the spacecraft will carry the 
instruments high above the Earth's atmosphere, protect them from 
the light and heat of the sun and the Earth, supply them with 
electrical power and commands and transmit the data they 
accumulate to the ground.
 
     Two of the three science instruments aboard the spacecraft, 
FIRAS and DIRBE, reside in a Dewar -- a giant "thermos bottle" -- 
filled with liquid helium to provide a stable, low-temperature 
environment within 2 degrees Celsius of absolute zero.
 
     The COBE spacecraft weighs 5,000 pounds, is 16 feet long and 
is 28 feet in diameter with its three solar panels deployed.  The 
upper half of the observatory is the instrument module, 
consisting of the three instruments, the liquid helium Dewar and 
a shield that is deployed when COBE reaches its orbit to protect 
the instruments from radiation from the sun and the Earth.  
 
     Directly under the instrument module is the spacecraft 
module which includes the mechanical support structure, the 
attitude control system and the spacecraft and instrument 
electronics.  To allow its instruments to scan the sky, COBE will 
spin on its axis at a rate of 0.8 rpm.  
 
     COBE's attitude control system will keep the spin axis 
pointed almost directly away from the Earth and 94 degrees away 
from the sun.  The sophisticated attitude control system is 
comprised of sun and Earth sensors, reaction wheels to provide 
control torque from the Earth's magnetic field, a pair of large 
rotating momentum wheels, electromagnets to transfer excess 
angular momentum from the spacecraft to the Earth's magnetic 
field and a complex set of control electronics.
 
     Monitoring of the status of the spacecraft and operational 
commands from the ground will go through the Tracking and Data 
Relay Satellite System (TDRSS).  The science data from the 
instruments will be recorded on two onboard tape recorders and 
played back to a ground receiving station at Wallops Island, Va., 
once a day.  These data then will be forwarded to the science 
team at the COBE Science Data Center, Goddard Space Flight 
Center, Greenbelt, Md.
 
     COBE will be launched by a two-stage Delta 5920 launch 
vehicle from Space Launch Complex 2 West at the Western Space and 
Missile Center, Vandenberg Air Force Base, Calif.  
 
                              - 6 -
  
     COBE will be placed into a circular, near polar orbit 559 
miles above the surface of the Earth.  Because the plane of the 
orbit will be inclined 99 degrees to the Equator, the orbital 
plane will precess (turn) approximately 1 degree per day, thus 
maintaining a constant orientation of the spacecraft and its 
orbit with respect to the sun.
 
     COBE's nominal mission lifetime is 1 year, allowing its 
instruments to scan the entire sky at least twice.  The actual 
operational lifetime of the FIRAS and DIRBE instruments may be 
somewhat longer and will be determined by the rate at which the 
liquid helium boils away as heat flows into the dewar.  It is 
anticipated that the spacecraft will be operated for a second 
year to allow the DMR to repeat its scans of the sky and achieve 
even greater sensitivity.
 
     The Delta 5920 is approximately 116 feet long and a maximum 
of 8 feet in diameter.  The first stage is a modified Thor 
booster incorporating nine Castor 4A strap-on, solid-fuel rocket 
motors.  The first stage main engine is gimbal-mounted and uses 
liquid oxygen and kerosene.  The second stage has a gimbal-
mounted, pressure-fed restartable engine fueled with liquid 
nitrogen tetroxide and aerozene 50.
 
     Injection into the final mission orbit is accomplished at 
completion of the second burn of the Delta second stage, 
approximately 1 hour after lift-off.  An 8-foot diameter fairing 
protects the spacecraft from aerodynamic heating during the boost 
and is jettisoned as soon as the vehicle leaves the sensible 
atmosphere (shortly after second stage ignition).  The fairing 
separation initiates signals to the spacecraft to properly 
configure the dewar vent valves in the observatory cryogenic 
cooler.  
                      MAJOR MISSION EVENTS
 
     Once the final mission orbit is reached, the Delta reorients 
to the required separation attitude and the Delta inertial 
guidance computer sends a signal to the spacecraft signal 
conditioning unit to start deployment.  That sequence begins with 
the RF/thermal shield deployment prior to spacecraft separation 
from the second stage.
 
     The COBE spacecraft is attached to the second stage Delta by 
a 6019 payload attach fitting.  Because the spacecraft requires a 
near-zero tip-off rate at separation, a two-step release system, 
consisting of three explosive nuts and a secondary latch system 
will be used.  At spacecraft separation, the Delta vehicle second 
stage will use cold gas to back away from the COBE spacecraft.
 
     The signal conditioning unit then initiates momentum wheel 
spin-up, solar array deployment, transmitter turn-on and antenna 
deployment.  The dewar cover is deployed by ground command 
approximately 4 days after separation.   
 
                              - 7 -
 
     Three solar arrays provide 712 watts of power to the 5,000-
lb. spacecraft.  During solar eclipses, batteries will be used to 
support the power loads and will be recharged during the sunlit 
portion of the orbit. 
 
                       COBE MISSION PHASES
 
LAUNCH
 
Location:  Space Launch Complex 2-West (SLC-2W), Western Space 
and Missile Center, Vandenberg Air Force Base, Calif.
 
Time/Date:  6:24 a.m. (PST),Thurs., Nov. 17, 1989 with a launch 
window of 30 minutes.
 
Launch vehicle:  Delta expendable launch vehicle (ELV) model 
5920.
 
 
EARLY ORBIT
 
Liftoff (LO) +57 min., 21 sec.:  The COBE spacecraft will be 
placed into its operational orbit of 559 miles by the second 
stage of the Delta 5920.  
 
LO+60 min., 28 sec.:  The Delta ELV sends discrete signals to 
start COBE's signal conditioning unit (SCU) -- a sophisticated 
electronic timer -- as the Delta is reoriented to the attitude 
required for the spacecraft to separate from the Delta.
 
LO+60 min., 29 sec.:  The COBE SCU turns on the telemetry 
transmitter.
 
LO+60 min., 30 sec.:  The SCU initiates thermal/radio frequency 
shield deployment.
 
LO+61 min., 30-45 sec.:  The Delta second stage releases and 
backs away from the COBE.
 
LO+61 min., 49 sec. to 62 min., 7 sec.:  The SCU initiates 
momentum wheel spin-up, solar array deployment and antenna 
deployment.
 
                OBSERVATORY/INSTRUMENT CHECK-OUT
 
     There will be a 14-day checkout phase, followed by an 
additional 16-day instrument characterization and calibration 
phase.  During this phase, transition to normal survey operations 
will occur.  After initial ground contact at separation, 
communications between COBE and the Earth will be via the 
Tracking and Data Relay Satellite System (TDRSS).  During 
observatory checkout, TDRSS support on an every orbit basis will 
be requested, to be gradually reduced over a transition period.
 
                               - 8 -
 
     Once the observatory and instruments have been fully 
checked, characterized and calibrated (approximately 30 days 
after launch), an S-band, single access forward and return link 
will be required for up to 2 hours per day.  The 2-hour total 
time will be scheduled over a 24-hour period on an every-other-
orbit basis (15 orbits per day).
 
     The observatory engineering checkout extends from day 1 
through day 3; the instrument engineering checkout goes from day 
3 through day 14; and the instrument characterization and 
calibration phase lasts from day 15 through day 30.  In addition, 
the day-to-day schedule will plan the following.
 
     Day 1:  RF acquisition, attitude stabilization and 
spacecraft subsystem initialization. 
 
     Day 2:  Differential Microwave Radiometer (DMR) instrument 
power up and calibration, and spacecraft subsystem checkout 
(including attitude maneuvers).
 
     Day 3:  Far Infrared Absolute Spectrophotometer (FIRAS) and 
Diffuse Infrared Background Explorer (DIRBE) instrument power up.
 
     Day 4:  Attitude maneuver and dewar cover ejection (by 
ground command from the Payload Operations Control Center at 
GSFC).  
 
     Day 5:  FIRAS instrument mechanism unlatching and additional 
instrument engineering checkout.
 
     Day 6:  Spacecraft spin-up to operational spin rate (0.815 
rpm).
 
     Day 7:  Attitude pitch maneuver checkout. 
 
     Day 8:  Attitude roll maneuver checkout and additional 
instrument checkout.
 
     Day 9-11:  Instrument checkout aided by attitude roll and 
pitch maneuvers.
 
     Day 12-14:  Instrument checkout and survey mode parameters 
adjustments.
 
     During the characterization and calibration phase, the 
instruments collect science data, are calibrated and are further 
characterized as orbital and astronomical events occur.
 
     By day 30 the instruments have been calibrated, characterized 
and adjusted to proceed with normal survey operations.
 
                              - 9 -
  
                       MISSION OPERATIONS
 
     The COBE flight operations team will control the COBE 
spacecraft from the Payload Operations Control Center, Goddard 
Space Flight Center, Greenbelt, Md., 24 hours a day, 7 days a 
week following launch.  During this time, the following data 
events are programmed daily:
 
    o  Real-time contact by the flight operations team through 
TDRSS every other COBE orbit.  This contact will allow for up-
link of stored commands once a day; monitoring of subsystems for 
health and safety; collection of tracking data and updating of 
the COBE clock drift.  This will maintain clock accuracy within 
10 milliseconds of Universal Time.
 
    o  One onboard tape recorder playback transmitted each day to 
Wallops Flight Facility (WFF), Va., for data relay to the COBE 
Science Data Room at Goddard Space Flight Center.  At the 655.4 
kilobits per second data dump rate, 24 hours of recorded data can 
be transmitted to Wallops in about 9 minutes.  
 
     There will be a minimum of three passes within range of the 
WFF ground station each day.  These passes will be a minimum of 
10 minutes long and will occur at nearly the same time each 
day.  This regularity will be used to routinely schedule the data 
acquisitions. 
 
                        MISSION LIFETIME
 
     COBE is planned to operate for 24 months following launch.  
The nominal mission lifetime is 12 months.  Minimum mission 
lifetimes to complete an all-sky survey are 6 months for FIRAS 
and DIRBE and 12 months for DMR.  FIRAS and DIRBE are planned to 
operate until the liquid cryogen is exhausted, while the short 
wavelength dectors on DIRBE can operate somewhat longer, current 
estimate is 14 months.  DMR is planned to operate for the full 24 
months.
 
 
                          COBE SCIENCE
 
     Cosmology, the study of the earliest beginnings and the 
largest structures in the universe, has been the subject of 
speculation for thousands of years.  Early in the twentieth 
century a remarkable combination of technology and new physical 
theory led scientists to put forward the Big Bang theory of the 
origin and evolution of the universe.  
 
     Some 25 years ago that theory received its strongest 
observational support to date with the discovery of the cosmic 
background radiation.  COBE's mission is to investigate the 
cosmic background radiation in sufficient detail to uncover the 
nature of the fundamental processes which have shaped the 
universe as seen today.
 
                             - 10 -
  
     The first step in the evolution of modern cosmology was 
development of the general theory of relativity by Albert 
Einstein.  Subsequently, in 1917, Willem de Sitter applied 
Einstein's equations to the universe as a whole with the 
startling result that the universe was not required to be static, 
but instead that the universe was likely in a state of expansion 
or collapse.  
 
     In the 1920's, Edwin Hubble provided the first observational 
confirmation of this picture through his pioneering work on faint 
nebulae.  Hubble proved that many of the nebulae were galaxies, 
huge collections of stars similar to the Milky Way galaxy, and 
also showed that these distant galaxies were receding from the 
Earth.  The nature of the recession was that the farther a galaxy 
lies from the Earth, the higher is its recessional velocity.
 
     Since the universe was observed to be in a state of 
expansion, it was natural to deduce that the universe was smaller 
in the past.  In fact, the evidence has led to the astounding 
conclusion that the galaxies were crowded together into a small, 
extremely dense volume, whose explosive expansion began some 15 
billion years ago and has been dubbed The Big Bang.  
 
     In the 1940's, George Gamow, Ralph Alpher and Robert Herman 
theorized that the early universe was not only extraordinarily 
dense, but also was extremely hot.  This led them to suggest that 
the nuclear reactions taking place in such a hot, dense 
environment accounted for the abundances of hydrogen and helium 
seen in the universe today, together with a small fraction of 
heavier elements.
 
     Alpher and Herman showed that another consequence of the hot 
Big Bang theory is that the universe should be filled with the 
radiation emitted by the hot matter.  That is, if scientists can 
look out in space, back in time to that distant early epoch, then 
they should see the glow of the initial fireball.  
 
     In 1964, Arno Penzias and Robert Wilson of the Bell 
Telephone Laboratories, using a new and very sensitive microwave 
receiver and antenna, found an unexplained source of noise or 
static which came to their antenna equally from all parts of the 
sky.  Their discovery sparked a number of independent 
observations and theoretical analyses to characterize the 
background radiation which they had found.  Today the evidence is 
overwhelming that Penzias and Wilson provided the first glimpse 
back to the primeval fireball which emerged from the Big Bang.  
 
     Since the initial measurements, study of the cosmic 
background radiation has been the subject of hundreds of 
experiments throughout the world, using ground-based, balloon- 
and rocket-borne telescopes.  Because the radiation is faint and 
easily distorted by the Earth's atmosphere, the investigation of 
the relic radiation from such sites is limited confirmation of 
the general shape of the spectrum and its overall uniformity.  
 
                             - 11 -
  
     However, hidden in the details of the spectral shape and 
spatial distribution of the background radiation are essential 
clues to the nature of the fundamental processes which shaped the 
early universe and produced the universe as it appears today.  
 
     COBE's instruments are designed to make full use of the 
vantage point of space to examine the cosmic background radiation 
with unprecedented sensitivity across a broad range of 
wavelengths.  COBE will scan the sky to look for spatial non-
uniformities at a sensitivity level many times what has been 
possible to date.  It will search the spectrum of the relic 
radiation for deviations from the simplest predicted shape, and 
it will carefully dissect the radiation at shorter wavelengths to 
look for evidence of the first stars and galaxies.
 
     COBE's search for variations in the brightness of the cosmic 
background radiation across the sky is designed to probe the 
mystery surrounding the formation of galaxies and clusters of 
galaxies in the universe.  
 
     To the present level of measurement accuracy, the background 
radiation appears smooth, characteristic of an early universe 
with an extraordinary degree of uniformity in its density and 
temperature.  Yet examination of the present day universe reveals 
a great deal of non-uniformity:  stars are collected into 
galaxies, galaxies are gathered into clusters and even these 
gigantic clusters of galaxies may themselves be clustered into 
even more immense structures.  Enormous voids, regions of space 
with almost no galaxies, exist between the clusters.  
 
     Theory indicates that the seeds of this universal structure 
must have been present in the early universe and the imprint of 
these seeds must be found as brightness variations in the relic 
radiation.  COBE has the sensitivity to search for the smallest 
conceivable brightness differences which are consistent with 
modern theory.
 
     COBE's investigation of the detailed spectral shape of the 
remnant radiation is motivated by the suggestion that enormously 
powerful and energetic processes may have taken place in the 
interval of time after the Big Bang and before the formation of 
galaxies.  For example, if massive black holes existed and 
swallowed large quantities of matter, the resulting energy 
release would have been sufficient to distort the spectrum of the 
fireball radiation to a degree measureable by COBE.
 
     Exotic processes, some of which have been suggested on the 
basis of modern theories of high energy particle physics, also 
have the potential of releasing immense quantities of radiative 
energy into the early universe and distorting the spectrum of the 
cosmic background radiation.  COBE will characterize the shape of 
the spectrum of the relic radiation at such a level of precision 
as to allow detailed study of the nature of these postulated 
energetic events.
 
                             - 12 -
  
     COBE's measurement of the diffuse background at wavelengths 
shorter than those characteristic of the remnant radiation from 
the initial fireball is intended to look for the radiation from 
the earliest stages of galaxy and star formation.  This faint 
signature must be detected against the foreground radiation from 
the solar system, the Milky Way galaxy and other nearby 
galaxies.  
 
     Detection of this signature requires the observational 
sensitivity and stability that has been carefully engineered into 
the COBE system.  Study of the radiation from the protogalaxies 
and protostars will aid scientists to probe into the nature of 
galaxy and star formation.
 
                     COBE SCIENCE QUESTIONS
 
     COBE will produce a complete map of the sky at each of 100 
different wavelengths to answer three primary questions:
 
1.  What is the variation in brightness of the cosmic background 
radiation across the sky?
 
2.  Does the cosmic background radiation have the spectrum 
predicted by contemporary cosmological theory?
 
3.  Can we detect the accumulated light from the first stars and 
galaxies?
 
                        COBE INSTRUMENTS
 
     COBE's three instruments -- the Differential Microwave 
Radiometer, the Far Infrared Absolute Spectrophotometer and the 
Diffuse Infrared Background Experiment -- will be able to observe 
the entire sky at least twice during the nominal mission lifetime 
of one year.
 
Differential Microwave Radiometer (DMR)
 
     This instrument will search for minute differences in the 
brightness of background radiation between different parts of the 
sky.  The DMR is capable of detecting brightness variations that 
are many times fainter than limits set by current observations 
and may reveal previously undiscovered physical phenomena.
 
     To distinguish the radiation of our galaxy from the true 
cosmic background radiation, the DMR will map the sky at three 
wavelengths:  3.3, 5.7, and 9.6 millimeters.  To accomplish this, 
it will have six receivers, two for each wavelength, mounted so 
that neither the sun nor Earth will shine directly on them.  Each 
receiver will sensitively measure the difference in microwave 
power entering two antennae looking at different parts of the sky.
 
                             - 13 -
  
    Far Infrared Absolute Spectrophotometer (FIRAS)
 
     This instrument will survey the sky to search for deviations 
in the spectrum of the cosmic background radiation from spectrum 
predicted on the basis of the simple Big Bang model.  FIRAS, as 
well as the DMR, can resolve the sky into 1,000 separate picture 
elements and will produce a spectrum for each element.  
Scientists will be able to compare the spectrum produced by COBE 
against predicted spectra with at least 100 times better accuracy 
than ever before.
 
     FIRAS looks out along the spin axis of the spacecraft.  It 
does not scan the sky as rapidly as the other two instruments 
onboard COBE but will nevertheless scan the entire sky twice 
during the nominal mission.  
 
     FIRAS will detect radiation by using a trumpet-shaped cone 
antenna.  Four detectors, each a tiny silicon resistance 
thermometer glued to a piece of blackened diamond only one 
thousandth of an inch thick, are used to detect the radiation 
collected by the cone antenna.  The diamond absorbs the 
infinitesimal heat from the cosmic background radiation and 
conducts this heat to the thermometer where the temperature is 
measured electrically.
 
     The data collected by FIRAS will be carefully analyzed to 
determine any deviations from the theoretically predicted 
spectrum.  Even the slightest discrepancy between measurement and 
theory will have great significance for cosmology.
 
Diffuse Infrared Background Experiment (DIRBE)
 
     This instrument will search for the light from the earliest 
stars and galaxies, luminous energy that is thought to have been 
produced some 200 million years after the Big Bang.  DIRBE 
operates in the infrared part of the spectrum, covering a 
wavelength range of 1 to 300 micrometers in 10 discrete bands.  
 
     It is an off-axis Gregorian telescope with baffles, stops, 
and super-polished mirrors, which will minimize response to 
unwanted "stray" light coming from outside its field-of-view.  
This design allows DIRBE to achieve the measurement accuracy 
necessary to distinguish between nearby objects and those at 
cosmological distances.
 
     DIRBE will not focus on a single object, but will instead 
measure the collective glow of millions of objects.  It will 
measure emission from warm dust in the Solar System and the Milky 
Way galaxy so precisely that scientists should be able to detect 
the uniform glow from the first stars and galaxies even if it is 
only 1 percent as bright as our local celestial environment. 
 
                             - 14 -
  
     Analysis of DIRBE data is complicated by the many kinds of 
known celestial objects as well as by the motion of the Earth 
within the interplanetary dust cloud.  When analysis is complete, 
a faint and uniform residual signal may remain after all known 
sources have been understood and subtracted.  The small residue 
would be the long-sought light of first, primordial objects.
 
             DELTA/COBE LAUNCH VEHICLE PREPARATIONS
 
     The COBE will be launched from Vandenberg Air Force Base, 
Calif., aboard a Delta expendable launch vehicle by a 90-member 
NASA/McDonnell Douglas launch team based at NASA's Kennedy Space 
Center, Fla.
 
Testing and Modifications
 
     The first stage of the Delta arrived Feb. 9 at Cape 
Canaveral Air Force Station in Florida.  There it underwent 
mission-specific modifications and electrical testing.  This 
stage is a standard Delta 1 booster upgraded with the Castor 4A 
strap-on solid rocket motors used on the Delta 2 launch vehicle.
 
     The Delta booster underwent about a month of testing and 
checkout of its hydraulic, propulsion and electrical systems.  
Following the completion of modifications and testing, the 
booster was shipped to Vandenberg Air Force Base, Calif.  It 
arrived there on April 1, to await its scheduled erection on the 
launch pad.
 
     The Delta second stage arrived at the Cape on Dec. 15, 1988, 
and underwent electrical and mechanical modifications to support 
the COBE mission.  This included attachment of a retro package 
containing two propulsion nozzles to allow the stage to back away 
from the spacecraft following separation.  This second stage 
modification is necessary since the COBE spacecraft does not 
require a third stage to achieve its final orbit.  The Delta 
second stage was shipped to California in early May.
 
     Before shipment to Vandenberg, the first and second stages 
were electrically mated for a simulated flight test, an exercise 
which simulates inflight events.  Before shipping the flight 
vehicle to Vandenberg, a pathfinder vehicle was erected on the 
launch pad to validate equipment and procedures and also to serve 
as a "dry run" for pad personnel.
 
Vehicle Assembly
 
     After arrival in California and temporary storage, the Delta 
was erected on Space Launch Complex 2-West.  The first stage was 
raised into position on Aug. 16.  The nine Castor 4A strap-on 
solid rockets, which augment thrust during the boost phase, were 
fastened to the first stage in sets of three beginning on Aug. 
14.  The second stage was hoisted atop the Delta first stage on 
Sept. 29.
 
                             - 15 -
  
Launch Pad Refurbishment
 
     KSC personnel have been involved in extensive refurbishment 
activities at the West Coast launch site for more than 2 years.  
SLC-2 West has been inactive since the Landsat 5 launch on March 
1, 1984.
 
COBE/Delta Launch Readiness
 
     A Simulated Flight, a post lift-off test which exercises the 
onboard systems active during ascent, occurred on Oct. 11.  Final 
testing of the vehicle for launch includes first-stage tanking 
with RP-1 fuel, a highly refined kerosene, and the cryogenic 
liquid oxygen.  This occurred on Oct. 27, together with a 
practice countdown and launch team certification.
 
     The COBE satellite was scheduled for mating with the Delta 
vehicle 2 days later to be followed by vehicle/spacecraft 
integrated testing.
 
     The next significant milestone occurs 3 days before launch 
with the final loading of the RP-1 propellant.  Two days before 
launch, the second stage will be loaded with storable 
propellants.  The liquid oxygen is loaded during the terminal 
count beginning at the T-75 minute mark.
 
     NASA has been launching the Delta rocket since 1960.  
Delta/COBE is the final official NASA launch of a NASA-owned 
Delta vehicle.
 
                     COBE MISSION MANAGEMENT
 
     The Office of Space Science and Applications (OSSA), NASA 
Headquarters, is responsible for the overall direction and 
evaluation of the COBE Program.  The Director of the Astrophysics 
Division has the Headquarter responsibility for COBE.  
 
     The Goddard Space Flight Center (GSFC) has Project 
Management responsibility for the design, development, testing, 
operation and analysis of the data.  The Office of Space 
Operations, NASA Headquarters, has overall tracking and data 
acquisition responsibility.  The Delta launch vehicle project 
management is the responsibility of GSFC as part of the NASA 
Expendable Launch Vehicle Program under the Office of Space 
Flight.  The responsible personnel within these areas are:
 
L.A. Fisk, Associate Administrator for Space Science and
   Applications
A.V. Diaz, Deputy Associate Administrator for Space Science and 
   Applications
C.J. Pellerin, Jr., Program Director
D.A. Gilman, Program Manager
L. Caroff, Program Scientist
 
                             - 16 -
  
W.B. Lenoir, Associate Administrator for Space Flight
J.B. Mahon, Deputy Associate Administrator for Space Flight
C.R. Gunn, Director, Unmanned Launch Vehicles and Upper Stages
P.T. Eaton, Chief, Small and Medium Launch Vehicles Branch
C.T. Force, Associate Administrator for Space Operations
J.W. Townsend, Jr., Center Director, GSFC
J.H. Trainor, Associate Director, GSFC
Peter Burr, Director, Flight Projects
D.L. Fahnestock, Director of Mission Operations and Data 
   Analysis, GSFC
J.R. Busse, Director of Engineering, GSFC
R. Mattson, COBE Project Manager, GSFC
J.M. Beckham, Delta Project Manager, GSFC
J.C. Mather, Project Scientist and Principal Investigator for 
   FIRAS, GSFC
N.W. Boggess, Deputy Project Scientist for Data, GSFC
D.K. McCarthy, Deputy COBE Project Manager, GSFC
J. Peddicord, Deputy Project Manager/Resources, GSFC
J.F. Turtil, Systems Engineer, GSFC
A.D. Fragomeni, Observatory Manager, GSFC
E.W. Young, Instruments Manager, GSFC
J.L. Wolfgang, Software Systems Manager, GSFC
R.G. Sanford, Mission Operations Manager, GSFC
Gen. F. S. McCartney, Center Director, KSC
J.T. Conway, Director, Payload Management and Operations
J.L. WomackDirector, Expendable Vehicles
S.M. Francois, Chief, Launch Operations Division
L. J. Holloway, Director, McDonnell Douglas Space Systems, Cape 
   Canaveral Air Force Station.
 
                      SCIENCE WORKING GROUP
 
Dr. Charles L. Bennett, GSFC, Deputy Principal Investigator for 
   Differential Microwave Radiometer (DMR)
Dr. Nancy W. Boggess, GSFC, Deputy Project Scientist for Data 
Dr. Edward S. Cheng, GSFC
Dr. Eli Dwek, GSFC
Dr. Lawrence Caroff, Program Scientist, NASA Headquarters
Dr. Samuel Gulkis, Jet Propulsion Laboratory, 
Dr. Michael G. Hauser, GSFC, Principal Investigator for Diffuse 
   Infrared Background Experiment (DIRBE)
Dr. Michael A. Janssen, Jet Propulsion Laboratory
Dr. Thomas Kelsall, GSFC, Deputy Principal Investigaor for DIRBE
Dr. Philip M. Lubin, University of California at Santa Barbara
Dr. John C. Mather, GSFC, Project Scientist, Principal 
   Investigator for Far Infrared Absolute Spectrophotometer 
Dr. Stephan S. Meyer, Massachusetts Institute of Technology
Dr. S. Harvey Moseley, Jr., GSFC
Dr. Thomas L. Murdock, General Research Corporation
Dr. Richard A. Shafer, GSFC
Dr. Robert F. Silverberg, GSFC
Dr. George F. Smoot, University of California at Berkeley, 
   Principal Investigator for DMR
 
                              - 17 -
  
Dr. Rainer Weiss, Massachusetts Institute of Technology, Chairman 
   of Science Working Group 
Dr. David T. Wilkinson, Princeton University
Dr. Edward L. Wright, University of California, Los Angeles, Data 
   Team Leader
 
                           CONTRACTORS
 
COMPANY                                 SUBSYSTEM/COMPONENT
 
Ball Aerospace Systems Div.             Dewar
P.O. Box 1062, Boulder, CO
 
Solarex                                 Solar Arrays
1335 Piccard Drive
Rockville, MD 20850
 
McDonnell Douglas Astronautics Co.      Batteries
P.O. Box 516                            Delta Launch Vehicle
St. Louis, MO 63166                     Launch Support Services
 
Motorola, Inc.                          Transponder
2501 S. Price Road
Chandler, AZ 85248
 
Ball Aerospace Systems Division         Antenna
Communications Systems
Colorado Engineering Center
10 Longs Peak Drive
Broomfield, CO 80020
 
Gulton Industries, Inc.                 Command/data handling
6600 Gulton, NE
Albuquerque, NM 87109
 
General Electric                        Tape recorder
Bldg. 10-5-3
Front and Cooper
Camden, NJK 18102
 
Engineering and Economic Research       Harness
10289 Aerospace Road
Seabrook, MD 20706
 
Information Development and             Instrument electronics
Applications, Inc.
10759 Tucker St.
Beltsville, MD  20705
 
Digital Equipment Corp.                Instrument ground support
8301 Professional Pl.                  equipment
Landover, MD 20785
 
                              - 18 - 
 
ST System Corp.                         Software
4400 Forbes Blvd.
Lanham, MD 20706
 
Barnes Engineering Company              Earth scanner assembly
88 Longhill Cross Roads
P.O. Box 867
Shelton, CT 06484
 
Applied Physics Laboratory              Momentum management
Johns Hopkins Road                      assembly
Laurel, MD 20707
 
Bendix Field Engineering Company        Reaction wheels
Teterboro, NJ 07608
 
ADCOLE Corporation                      Sun sensors
669 Forest St.
Marlkborough, MA 01752
 
Northrop Precision Products Div.        Gyros
100 Morse St., Norwood, MA 02062
 
Northrop Services, Inc.                 Integration and test
108 Powers Court, Sterling, VA
 
Swales                                  Mechanical design
5050 Powder Mill Road, Beltsville, MD 
 
                             - end -
 
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |
 
------------------------------
 

Newsgroups: sci.space
Subject: NASA Headline News for 11/20/89 (Forwarded)
Date: 20 Nov 89 19:23:07 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
-----------------------------------------------------------------
Monday, November 20, 1989                     Audio: 202/755-1788
-----------------------------------------------------------------
 
    This is NASA Headline News for Monday, November 20:
   
    Project officials at Goddard Space Flight Center report that the
Cosmic Background Explorer satellite is operating well following its
launch into near polar orbit last Saturday.   The COBE spacecraft was
placed into orbit by a Delta rocket.  The Delta rose off the pad ten
minutes into the half-hour launch window after high winds aloft
finally abated enough to allow the lift-off.  COBE was placed into a
559-mile high circular orbit. 
  
    As COBE scientists prepare for their one-year search for remnants 
of the Big Bang some 15 billion years ago, astronomers at Palomar 
Observatory report that they have located a quasar 14 billion light 
years from Earth, making it the most distant and oldest object yet
discovered. 
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon, 
Eastern time.
-----------------------------------------------------------------
A service of the Internal Communications Branch (LPC), NASA 
Headquarters, Washington, D.C.

Newsgroups: sci.space
Subject: COBE Status for 11/21/89 (Forwarded)
Date: 21 Nov 89 17:25:44 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
        Cosmic Background Explorer
        Status Report
        November 21, 1989
  
    Four days after liftoff from the Vandenberg Air Force Base, the
Cosmic Background Explorer (COBE) continues to perform flawlessly. 
Today at 6:19 a.m. EST, a critical milestone was passed as the cover
was ejected from the Dewar. 
 
    This giant "thermos bottle" houses two of COBE's three
instruments: the Diffuse Infrared Background Experiment (DIRBE) and
the Far Infrared Absolute Spectrophotometer (FIRAS).  The liquid
helium in the Dewar keeps the instruments below 2 degrees Kelvin--cool
enough to detect remnant light from the Big Bang and from the first
stars and galaxies. 
 
    This remnant light has been shifted by the expansion of the
Universe from ultraviolet and visible into the infrared and
submillimeter waves (called "red shift"), which will be detected by
these instruments. 
 
    DIRBE began operating at 11 a.m. EST today.  Tomorrow at 6 a.m.
EST, FIRAS' Mirror Transport Mechanism, will be unlatched allowing the
last instrument to begin operating. 
 
    The Differential Microwave Radiometer, which will look for
differences in brightness among parts of the sky, began mapping the
sky on Sunday, November 19.  The maps indicate that the instrument is
performing well. 

Newsgroups: sci.space,sci.astro
Subject: COBE Update 12/1/89 (Forwarded)
Date: 2 Dec 89 01:21:33 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                            COBE UPDATE
                         DECEMBER 1, 1989
 
    Goddard's Cosmic Background Explorer (COBE) continues to function
normally from its orbit 559 miles from Earth and is in the final
phases of instrument check-out.   The COBE may be viewed by the
unaided eye, atmospheric conditions permitting, at approximately 5:35
p.m. each afternoon as it approaches from the south.  In the meantime,
the COBE continues to downlink data twice a day to Wallops Flight
Facility for relay to the COBE science data room at Goddard.  The
Goddard-managed spacecraft was launched on November 18 from Vandenberg
Air Force Base, California.  
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

    	There is an in-depth article on the COBE satellite in the January
    1990 issue of SCIENTIFIC AMERICAN, written by several of the project
    designers.
    
    	Larry
                                                         

Newsgroups: sci.space,sci.astro
Subject: COBE Update - 01/12/90 (Forwarded)
Date: 13 Jan 90 00:56:08 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
    EARLY COBE RESULTS IN ACCORD WITH BIG BANG THEORY
 
     A major advance in cosmology was revealed today as early 
results from NASA's Cosmic Background Explorer (COBE), launched 
last fall, were presented at the American Astronomical Society 
meetings held at Crystal City, Va.
 
     Preliminary results are in accord with the predictions of 
the Big Bang theory, which traces the origin of the universe to a 
primordial explosion some 15 billion years ago.  The universe 
today shows that sometime after the Big Bang additional 
release(s) of energy must have occurred.  COBE's new results 
severely limit the magnitude and character of such a release.
 
     Limited COBE data now indicate a smooth, uniform Big Bang.  
However, small deviations from a blackbody spectrum -- the 
characteristic signature of radiation from an opaque object of 
uniform temperature -- would reveal energetic processes in the 
early universe.
 
     COBE scientists reported that the instruments onboard the 
spacecraft are performing exquisitely with precision never before 
achieved.  Such precision puts new constraints on theories to  
explain the present universe.
 
     Over the 2-year mission, COBE will continue to collect much 
more data.  Scientists expect the final data to be ten times more 
sensitive than these early results. 
 
     These early results were reported to the American 
Astronomical Society by the principal investigators for the three 
instruments:  the Far Infrared Absolute Spectrophotometer 
(FIRAS), the Differential Microwave Radiometer (DMR) and the 
Diffuse Infrared Background Experiment (DIRBE).
 
     Dr. John Mather, Principal Investigator for FIRAS and 
Project Scientist, reported that the spectrum measurement of the 
cosmic microwave background (a relic of the Big Bang) is highly 
accurate and heralds a major advance in observational 
cosmology.  Based on a small sample of data, FIRAS measurements 
show no deviation from a blackbody spectrum as large as one 
percent of the peak brightness of the cosmic microwave background 
over the wavelength range 500 microns to 5 millimeters.
 
     When FIRAS captured these data, it was pointed toward the 
North Galactic Pole, where emissions from our own galaxy, the 
Milky Way, are expected to be low.  Using only 9 minutes of sky 
observations, FIRAS already has produced the most precise cosmic 
microwave background spectrum measurement ever made.  Much more 
exposure time will be obtained during the mission.
 
     Dr. George Smoot, Principal Investigator for the DMR, 
presented the first COBE maps of the variation in brightness of 
the cosmic background radiation over the sky.  The maps, taken at 
frequencies of 31, 53 and 90 GHz, indicate that the cosmic 
background radiation is equally bright in all directions.  The 
question of what and where are the progenitors of galaxies and 
large clusters of galaxies is still open.
 
     The preliminary results from DMR are based on only about 20 
days of data and also indicate the extraordinary smoothness of 
the universe.  This instrument will continue to take data for two 
years, which will improve its sensitivity to search for 
anisotropies, or "lumpiness," in the early universe well beyond 
the present limits.
 
     Dr. Michael Hauser, Principal Investigator for DIRBE, showed 
maps of half the sky taken at wavelengths of 1.2, 12, and 240 
microns (never before achieved for the 1.2 and 240 micron 
wavelengths).  Final maps from this experiment will enable COBE 
scientists to search for radiation from the first stars and 
galaxies.  
 
     These initial maps, taken over a one-week period, clearly 
reveal bright foreground radiation from stars, dust in our own 
Solar System, and interstellar dust.  DIRBE maps half the entire 
sky every day at 10 different wavelengths and it covers the 
entire sky in 6 months.
 
     At the AAS meeting, Dr. Nancy W. Boggess, Deputy Project 
Scientist, gave an overview of the mission, reporting that COBE 
has met or exceeded all design goals.  At launch, all systems 
deployed as planned.  The RF/Thermal Shield, which protects all 
three instruments from solar and terrestrial radiation, is more 
spectacular than hoped.  
 
     This efficient shield results in a lower than anticipated 
temperature of the dewar, the giant thermos bottle that maintains 
the FIRAS and DIRBE at operating temperatures below 2 degrees K.
The dewar now operates at 1.4 degrees K, though designed for 1.6 
degrees K less. The lower temperature will enable the detectors 
of the COBE instruments to be more sensitive.  It also makes the 
lifetime of the liquid helium, which keeps the dewar 
cryogenically cooled, longer than the original 12 to 14 months.  
It is now expected to last 430 days.  
 
     COBE was launched Nov. 18, 1989, aboard the last NASA-owned 
Delta rocket, from the Vandenberg Air Force Base, Calif.  COBE is 
managed by NASA's Goddard Space Flight Center, Greenbelt, Md., 
for the Office of Space Science and Applications.  GSFC is 
responsible for the design, development and flight operations, as 
well as for the development of the analysis software and for the 
production of the final mission data sets.
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

Newsgroups: sci.space
Subject: NASA Headline News for 04/18/90 (Forwarded)
Date: 18 Apr 90 17:31:52 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
-----------------------------------------------------------------
Wednesday, April 18, 1990             Audio Service: 202/755-1788
-----------------------------------------------------------------
This is NASA Headline News for Wednesday, April 18:
 
Scientists are puzzled with some data from the Cosmic Background 
Explorer Satellite launched last November, but also pleased with 
a visual byproduct.  Wire service reports say scientists meeting 
in Washington, D.C., are confounded by data which indicate an 
unexpectedly smooth and uniform expansion of the Universe and no 
indication of other cataclysmic events that had been theorized.  
Michael Hauser, of NASA's Goddard Space Flight Center says, "The 
quandry is deepening".  A color image of the galactic center of 
the Milky Way was released yesterday free of cosmic dust that has 
obscured our galaxy's center previously. 
_________________________________________________________________
Here's the broadcast schedule for Public Affairs events on NASA 
Select TV.  All times are EDT.
 
    Thursday, April 19:
 
    11:30 a.m.     NASA Update will be transmitted.
  
    Friday, April 20:
 
    10:30 a.m.     STS-35 astronaut news conference from
                   Johnson Space Center.
  
    Sunday, April 22:
 
     1:00 p.m.     STS-31  crew arrival at KSC
  
    Tuesday, April 24..(Subject to change)
 
     9:00 a.m.     STS-31 Countdown Status Report
 
    10:00 a.m.     APU/telescope Status Report
 
    11:00 a.m.     Prelaunch News Conference
  
    Wednesday, April 25..(Subject to change)
 
      4:00 a.m.    STS-31 mission launch coverage begins.
 
NOTE:  During the STS-31 mission television highlights will be 
transmitted on Satcom F1R, transponder #13 at 12 midnight, EDT, 
for the benefits of TV stations and educational institutions in 
Alaska and Hawaii.
 
All events and times are subject to change without notice.
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon, 
EDT.
-----------------------------------------------------------------
A service of the Internal Communications Branch, NASA Hq.

Date: 21 Sep 90 22:19:43 GMT
From: [email protected]  (Peter E. Yee)
Subject: COBE enters new phase of operations after helium depletion (Forwarded)
 
Michael Braukus
Headquarters, Washington, D.C.                          September 21, 1990
(Phone:  202/453-1549)
 
Randee Exler 
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-7277)
 
    RELEASE:  90-129
 
    COBE ENTERS NEW PHASE OF OPERATIONS AFTER HELIUM DEPLETION
 
     With the depletion of its liquid helium supply this morning,
NASA's Cosmic Background Explorer (COBE) is beginning a new phase of
operations, extending its search for structure in the early Universe. 
 
     The liquid helium was housed inside a dewar, a vacuum insulated
"thermos", that provided a stable, low temperature environment for two
instruments -- the Far Infrared Absolute Spectrophotometer (FIRAS) and
the Diffuse Infrared Background Experiment (DIRBE).  The dewar
contained 600 liters of liquid helium. 
 
     Launched last November 18 into a polar orbit approximately 555
statute miles high, COBE was designed specifically to measure the
remnant of the Big Bang, the primeval explosion that started the
expanding Universe.  It completed one full-sky survey in mid-June and
continued with a second survey before helium depletion. 
 
     Both FIRAS and DIRBE require cooling to less than 2 degrees
Kelvin (K) (two degrees above absolute zero), for full sensitivity. 
On the Kelvin scale, average room temperature is 300 degrees K. 
 
     During the next few months, the inside of the dewar which held
the cryogen, is expected to rise to approximately 80 degrees K.  The
near infrared bands in the DIRBE will continue to function at these
higher temperatures. 
 
     Another instrument, the Differential Microwave Radiometer (DMR),
consists of six separate receivers at three different frequencies
located outside the dewar.  The DMR does not require cryogenic cooling
and will continue re-mapping the sky to further increase the
sensitivity of its measurements. 
 
     Of the three instruments, only the FIRAS will no longer take
data, since it requires a very low operating temperature.  FIRAS, as
well as the other instruments, has observed each part of the sky
multiple times during the course of the year.  The FIRAS already has
produced the most sensitive, accurate measurements of the spectrum
ever achieved, according to project officials. 
 
     Even at this early stage of data processing, the COBE data have
made enormous contributions to the field of observational cosmology. 
The first peer-reviewed article on the spectrum results was called by
referees "one of the most important cosmological experiments of this
century." 
 
     Just eight weeks after launch, preliminary results were presented
that revealed the first definitive spectrum of the cosmic background
radiation.  The spectrum showed that the Big Bang theory was confirmed
with textbook perfect agreement with predictions, but further analysis
may well reveal small and very important differences.  DMR maps
confirmed that the Universe was extremely homogeneous (or smooth) at
this early stage, also in accordance with the Big Bang theory.  DIRBE
maps have provided unprecedented new views of our local cosmic
environment, the solar system and the Milky Way Galaxy.  These maps
could provide the first definitive search for the elusive cosmic
infrared background to reveal the glow from the first generation of
objects in the Universe. 
 
     The complex COBE satellite represents a major advancement in
scientific technology, and carries the first cryogenic scientific
instruments with moving parts to fly in a satellite.  This also is the
first time that cryogenic instruments carried their own absolute
calibrators.  All systems met or exceeded their design specifications.
 
     The COBE mission now has a great quantity of data that must
undergo extensive processing.  The "quick-look" data show that the
data are of very high quality, and indicate that COBE's instruments
have good sensitivity, stability and linearity. 
 
     The challenge ahead is to reduce and analyze the data carefully
to understand the conditions in the early Universe.  Calibration and
interpretation of signals from nearby regions that confuse our view of
the Big Bang must be examined and understood.  The great mystery still
remains:  How did the Universe split itself into the great objects that
exist today, including galaxies, clusters of galaxies and huge empty
areas between them?  The COBE data are expected to hold the basic
evidence of this process when the analysis is complete. 
 
     The Goddard Space Flight Center is responsible for the COBE
development, operation, and data processing. 
 

From: [email protected] (Peter E. Yee)
Date: 14 Jan 91 20:31:01 GMT
Organization: NASA Ames Research Center, Moffett Field, CA

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                   January 14, 1991
(Phone:  202/453-1549)                           Noon

Randee Exler
Goddard Space Flight Center, Md.
(Phone:  301/286-7277)


RELEASE:  91-6

COBE MAPS INTERSTELLAR MATERIAL IN MILKY WAY GALAXY


     For the first time, astronomers have mapped the distribution 
of nitrogen throughout our galaxy.  The new observations were 
taken by an instrument on NASA's Cosmic Background Explorer, the 
Far Infrared Absolute Spectrophotometer.

     This all-sky survey, along with additional maps of carbon 
and dust, provides quantitative information that may enable 
scientists to understand better the heating and cooling processes 
that take place throughout the Milky Way.  These accomplishments 
were reported today at the American Astronomical Society meeting 
in Philadelphia by members of the COBE science team.

     COBE scientists presented images that show the locations in 
the galaxy of ionized nitrogen.  The nitrogen map of the Milky 
Way is at the wavelength of 205 micrometers and is the first 
detection of this important spectral line.  The carbon map was 
produced at 158 micrometers and the dust map at 205 micrometer 
wavelengths.

     "Before COBE, it was not possible to map the whole galaxy in 
this way, although these atomic emissions are the dominant way in 
which the interstellar gas cools," said COBE Project Scientist 
Dr. John C. Mather, who added that COBE's unique capabilities 
permit these all-sky measurements unencumbered by atmospheric and 
instrument emission.  Five months of data were used to produce 
the maps.

     The emission from ionized nitrogen atoms was found to occur 
at a precise wavelength of 205.3 micrometers.  The exact 
determination of this wavelength, which had never been measured 
before, is important because it will enable astronomers to build 
future instruments to map this radiation with greater spatial 
resolution.

     The COBE data also were used to measure the total energy 
emitted by the dust, neutral carbon atoms and carbon monoxide 
molecules in the interstellar gas, showing that our galaxy is a 
typical spiral galaxy.

     These new data show that carbon and nitrogen atoms -- some 
of the key building blocks of life -- are extremely widespread in 
the thin gas that fills the space between the stars.  These atoms 
are created inside stars by nuclear reactions and then released 
back into space by stellar winds or explosions at the ends of 
stellar lives.

     The data also confirm theories that the mixture of gas and 
dust in our galaxy is heated by starlight striking dust grains 
and cooled by the carbon and nitrogen emissions.  The greatest 
concentrations of the atoms and dust grains are in the plane of 
the galaxy.

     The data were taken using the Far Infrared Absolute 
Spectrophotometer (FIRAS), one of the three instruments aboard 
COBE, NASA's first satellite primarily designed for cosmological 
studies.  COBE, launched from Vandenberg Air Force Base, Calif., 
Nov. 18, 1989, primarily studies the diffuse microwave and 
infrared light coming from the "big bang" at the beginning of the 
currently observable universe and from the first objects that 
formed after this primordial explosion.

     FIRAS is the same instrument that 1 year ago enabled COBE 
scientists to report the most precise measurements ever obtained 
of the spectrum of the cosmic microwave background radiation.  
The new results show that this instrument also is remarkably 
sensitive to emissions of dust grains, atoms and molecules in the 
galaxy.

     The report was made by Drs. John C. Mather, Richard A. 
Shafer and Charles L. Bennett of NASA's Goddard Space Flight 
Center, Greenbelt, Md., and Dr. Edward L. Wright, of the 
University of California.

     The data were analyzed at the Goddard Space Flight Center. 
The scientific team includes members at Massachusetts Institute 
of Technology, Cambridge, Mass.; General Research Corp., Danvers, 
Mass.; Princeton University, N.J.; University of California at 
Los Angeles, and the Jet Propulsion Laboratory, Pasadena, Calif., 
as well as the Goddard Space Flight Center.  Scientists at 
General Sciences Corp., Laurel, Md., Applied Research Corp., 
Landover, Md.; Universities Space Research Association, 
Greenbelt, Md., and Systems Technologies Corp., Lanham, Md., 
support the reduction and analysis of the data.

     This research is supported by NASA's Astrophysics Division 
of the Office of Space Science and Applications.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                 April 23, 1992

Randee Exler
Goddard Space Flight Center, Greenbelt, Md.

RELEASE:  92-51


     Scientists announced today, at the American Physical
Society's meeting held in Washington, D.C., that they have
detected the long-sought variations within the glow from the
Big Bang  -- the primeval explosion that began the Universe
15 billion years ago -- using NASA's Cosmic Background
Explorer (COBE).  This detection is a major milestone in a
25-year search and supports theories explaining  how the
initial expansion happened.

     These variations show up as temperature fluctuations in
the sky, revealed by statistical analysis of maps made by the
Differential Microwave Radiometers (DMR) on the COBE
satellite.  The fluctuations are extremely faint, only about
thirty millionths of a degree warmer or cooler than the rest
of the sky, which is itself very cold --  only 2.73 degrees
above absolute zero.  The DMR is still gathering data and the
measurements are expected to become even more precise.

     The Big Bang theory was initially suggested because it
explains why distant galaxies are receding from us at
enormous speeds, as though all galaxies started moving away
from the same location a long time ago.  The theory also
predicts the existence of cosmic background radiation -- the
glow left over from the explosion itself.  The Big Bang
theory received its strongest confirmation when this
radiation was discovered in 1964 by Arno Penzias and Robert
Wilson, who later won the Nobel Prize for this discovery.

     Although the Big Bang theory is widely accepted, there
have been several unresolved mysteries.  How could all of the
matter and energy in the Universe become so evenly mixed in
the instant following the Big Bang?  How could this evenly
distributed matter then break up spontaneously into objects
of all sizes, such as galaxies and clusters of galaxies?  The
temperature variations seen by COBE help to resolve these
mysteries.

     "The COBE receivers mapped the sky as it would appear if
our eyes could see microwaves at the wavelengths 3.3, 5.7 and
9.6 mm, which is about 10,000 times longer than the
wavelength of ordinary light," explained Dr. George Smoot,
University of California, Berkeley, the leader of the team
that made this discovery.  "Most of the energy received from
the sky at these wavelengths is from the cosmic background
radiation of the Big Bang, but it is extremely faint by human
standards.

     "Hundreds of millions of measurements were made by the
DMR over the course of a year, and then combined to make
pictures of the sky.  Making sure all the measurements were
combined correctly required exquisitely careful computer
analysis," Smoot explained.

     Another COBE scientist, Dr. Charles Bennett of the
Goddard Space Flight Center, Greenbelt, Md., explained that a
major challenge for the team was to distinguish the Big Bang
signals from those coming from our own Milky Way Galaxy.
"The Milky Way emits microwaves that appear mostly
concentrated in a narrow  zone around the sky.  We compared
the signals at different positions and at different
wavelengths to separate the radiation of the Big Bang from
that of the Milky Way Galaxy," said Dr. Bennett.

     The temperatures and sizes of the fluctuations in the
background radiation COBE detected agree with the predictions
of "inflationary cosmology," a theory that says the structure
and behavior of the Universe were determined by minute
fluctuations occurring when the Universe was much younger
than one-trillionth of a second.  The COBE results provide
new evidence in support of the "inflationary" scenario.

     The amount of gravity provided by these visible
fluctuations was inadequate to draw together the galaxies and
clusters of galaxies.  Instead, astronomers conclude that the
galaxies formed only because most of the material in the
Universe is invisible and totally unlike ordinary matter.

     This "dark matter" provides the necessary gravitational
attraction for forming galaxies.  The fluctuations seen by
COBE are too small to explain how the visible matter in the
young Universe could condense into the galaxies that now
exist.  According to COBE scientist Dr. Edward Wright from
the University of California, Los Angeles, the COBE
measurements support theories postulating large amounts of
dark matter.

     "These theories say that most of the matter in the
Universe is invisible to us and must be a new kind of matter,
not yet detected in our laboratories," he explained.
"Nevertheless, we need such invisible matter to explain how
galaxies formed in the early Universe and gathered themselves
together into huge clusters.  Ordinary matter would be
attracted into regions of concentrated dark matter, and the
Universe as we know it today could develop, eventually
leading to the formation of galaxies, stars and planets,"
Wright said.

     COBE was launched in November, 1989, from Vandenberg Air
Force Base, Calif., aboard a Goddard-managed Delta launch
vehicle.  The Goddard Space Flight Center, Greenbelt, Md.,
manages COBE for NASA's Office of Space Science and
Applications, Astrophysics Division, Washington, D.C.
 

COSMIC BACKGROUND EXPLORER (COBE): COBE continues to acquire data
from the Differential Microwave Radiometer (DMR) and Difuse
Infrared Background Experiment without any problems.  The project
scientists continue analyzing data from all three COBE
instruments including the Far Infrared Absolute Spectrophotometer
(FIRAS).  In April, COBE scientists announced that DMR data show
that the cosmic explosion that began the expanding Universe 15
billion years ago was not perfectly smooth and uniform.  Regions
with different  temperatures, densitites and sizes were produced.
The spacecraft  was rolled back to its normal four-degree Sun
angle this month. This is the last maneuver needed to reconfigure
the spacecraft after its three-month eclipse season (May - July).
The maneuver was not performed sooner to protect the spacecraft
from sunlight reflecting off of both the atmosphere and ice over
the South Pole.  COBE, built and managed by Goddard, launched
November 18, 1989 on a Delta II rocket.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                             January 7, 1993

Randee Exler
Goddard Space Flight Center, Greenbelt, Md.

RELEASE:  93-5


        The Big Bang Theory passed its toughest test yet with the latest
results reported from NASA's Cosmic Background Explorer (COBE) team at the
American Astronomical Society meeting in Phoenix, Ariz., today.

        Precise measurements made by COBE's FIRAS of the afterglow from the Big
Bang -- the primeval explosion that began the universe approximately 15 billion
years ago -- show that 99.97 percent of the early radiant energy of the
universe was released within the first year after the Big Bang itself.

        "Radiant energy" is energy emitted in any form of light, from x-rays
and gamma rays to visible and infrared light or even radio waves.  COBE's Far
Infrared Absolute Spectrophotometer (FIRAS) was designed to receive the
microwave and infrared energy from the Big Bang.

        "The Big Bang theory comes out a winner," said COBE Project Scientist
and FIRAS Principal Investigator Dr. John C. Mather of NASA's Goddard Space
Flight Center, Greenbelt, Md. "This is the ultimate in tracing one's cosmic
roots," Mather said.

        All theories that attempt to explain the origin of large scale
structure seen in the universe today now must conform to the constraints
imposed by these latest measurements.

        This includes theories that postulate large amounts of energy released
by such things as black holes, exploding supermassive stars or the decay of
unstable elementary particles.  In other words, there were not a lot of "little
bangs," as suggested by some theories.

        The Big Bang Theory predicts that the spectrum of relic radiation
should be that of a perfect "black body" unless there were major energy
releases more than a year after the explosion. (A black body is a hypothetical
cosmic body that absorbs all radiation falling on it, but reflects none
what-so-ever.  A black body emits at the same temperature at every wavelength.)
These latest FIRAS results reveal that later energy releases did not occur.

        The COBE scientists now can say that the temperature of the afterglow
radiation is 2.726 degrees above absolute zero (273 degrees below zero on the
Celsius scale) with an uncertainty of only 0.01 degrees.

        Today's announcement is the result of analyzing data from the FIRAS
during its 10 months of observations.  Hundreds of millions of measurements
were combined to obtain these unprecedentedly pre "Making certain that all of
the measurements were combined correctly required exquisitely careful work and
lengthy analysis by a large team of COBE scientists," Mather reported.

        "We are seeing the cold glow still remaining from the initially very
hot Big Bang. These results now limit the size of any 'after shocks' following
the Big Bang. The closer we examine the Big Bang the simpler the picture gets,"
said Mather.

        "It took us 18 years of careful effort to reach this point, but now we
can say that the Big Bang Theory has been tested against observations to a fine
degree of precision," explained Mather.

        "Experimental evidence of the Big Bang was first found by Edwin Hubble
in the 1920's.  He found that distant galaxies in ever direction are going away
from us with speeds proportional to their distance.  Therefore, gallaxies that
are farther away are going faster.  This is exactly the pattern that would
occur if the entire universe originated in a single explosion, now called the
Big Bang.

        Papers on these results and their implications soon will be submitted
to the Astrophysical Journal for publication.

        COBE, launched Nov. 18, 1989, is managed by NASA's Goddard Space Flight
Center, for NASA's Office of Space Science and Applications, Astrophysics
Division, Washington, D.C.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61

Article: 75056
Newsgroups: sci.space
From: [email protected] (Urban Fredriksson)
Subject: News from Flight International
Sender: [email protected] (Root System)
Organization: None. I speak only for myself.
Date: Tue, 12 Oct 1993 18:26:38 GMT
 
When commander Tsiblyev's space suit overheated on Sept 28th, his and
Serebrov's space walk was cut short at 1h 52m. Their main task was to
film the exterior of Mir to check for possible damage from the Perseid
meteor shower. 
 
The next Indian PSLV (polar satellite launch vehicle) launch will be
delayed at least two year. The first launch failed when at the second
stage's separation the booster's pitch attitude was altered, leaving
it 75 km lower at third stage cut-off, making it impossible to reach
orbital velocity with the fourth stage. Otherwise "it worked
perfectly", including the new liquid- propellant Vikas second stage
and the 129 ton solid propellant first stage with flexed nozzle (two
of these will be used as strap on booster for the GSLV (geo-stationary
launch vehicle). 
 
The COBE (COsmic Background Explorer) satellite is pieces of debris.
So far, 30 small objects have been tracked. 
--
 Urban Fredriksson  [email protected] 

Article: 75154
From: [email protected] (David Ward)
Newsgroups: sci.space
Subject: Re: News from Flight International
Date: 13 Oct 1993 12:52 EST
Organization: Goddard Space Flight Center - Robotics Lab
 
In article <[email protected]>,
[email protected] (John Fleming) writes... 

>In article <urf.750450398@sw2001>, [email protected] (Urban Fredriksson) wrote:
>> 
>> [ stuff deleted ]
>>
>> The COBE (cosmic background explorer) satellite is pieces of
>                                                     ^^^^^^^^^
>> debris. So far, 30 small objects have been tracked.
>  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
>EEK!!  What is this!!!???  Did I just miss something?  Is COBE ok?  
>Did it blow up? :-(
> 
>Or is it just paint flakes and atomic oxygen erosion of thermal
>blankets and frozen blobs of leaking coolant?  Not that anyone could say 
>for sure, but I'd hate to see another publicly-visible satellite
>faux pas.
>-- 
>John A. Fleming, Motorola Satellite Communications,
>[email protected]

>"In the difficult years that lie ahead, we must remember that the snows of 
>Olympus lie silently beneath the stars, waiting for our grandchildren."
> - Arthur Clarke
 
Relax--COBE's still in one operational piece, although not for long.
Science operations are scheduled to end on COBE this winter (not
exactly sure of the date).  I think the small objects are simply
debris/ contamination that may have come off the spacecraft.  Someone
has speculated that the objects may be thermal blankets that have come
loose, but I haven't heard of any detrimental effects that have been
seen on the spacecraft. 
 
David W. @ GSFC

Date: Mon, 27 Dec 1993 16:52:29 +0500 (EST)
From: A Close Encounter of the Learning Kind <[email protected]>
Subject: NASA ENDS COSMIC BACKGROUND EXPLORER SCIENCE OPERATIONS

12/23/93: NASA ENDS COSMIC BACKGROUND EXPLORER SCIENCE OPERATIONS 

Donald L. Savage
Headquarters, Washington, D.C.                December 23, 1993

Michael Finneran 
Goddard Space Flight Center, Greenbelt, Md.

RELEASE:  93-228

     The final operational instrument on NASA's first spacecraft to
explore the origins of the Universe will be turned off today after
completing 4 years of landmark research, including confirmation of the
Big Bang theory that says the Universe was created in a single
momentous explosion. 

     The Cosmic Background Explorer (COBE) spacecraft, built and
managed by the Goddard Space Flight Center (GSFC), Greenbelt, Md.,
will be used as an engineering training and test satellite by NASA's
Wallops Flight Facility, Wallops Island, Va. beginning in January
after Goddard spacecraft controllers conclude engineering operations. 

     "COBE has more than achieved its technical goals," said Dr. John
Mather, Project Scientist at GSFC.  "It has observed the Universe as
it was at its birth.  It's done everything we asked it to do, and it's
a proud day for us to declare our flight operations complete." 

     Launched on Nov. 9, 1989, on a Delta rocket, COBE's primary
science mission requirement called for one year of observations. Near
the end of its first year the liquid helium coolant needed by two of
the three instruments was exhausted, leaving one instrument and some
channels of a second instrument operational. 

     COBE was the first space mission to address basic questions of
modern cosmology, such as how the Universe began, how it evolved to
its present state and what forces govern this evolution.  According to
the Big Bang theory, the Universe was created about 15 billion years
ago in a violent cosmic explosion that hurled primeval matter in all
directions.   COBE became well known for its very precise measurements
confirming the Big Bang theory and for its detection of the largest
and oldest objects ever discovered. 

     Scientists styudying the mysterious conditions present in the
early Universe and how it evolved into stars and galaxies used precise
measurements from three COBE instruments: 

	*   The Far Infrared Absolute Spectrophotometer (FIRAS),
designed to measure the spectrum of the Cosmic Microwave Background to
great accuracy. 

	*   The Differential Microwave Radiometers (DMR), designed to
measure the "lumpiness," or anisotropies, in the Universe that existed
just 300,000 years after the Big Bang. 

	*   The Diffuse Infrared Background Experiment (DIRBE),
designed to search for the glow from the first stars and galaxies in
the Universe. 

     The FIRAS instrument measured the spectrum of the Cosmic
Microwave Background radiation with unprecedented accuracy, showing
that it is the same as the spectrum predicted by the Big Bang theory. 
Since the COBE measurements show no deviations from the spectrum
predicted by the Big Bang, it is known now that 99.97 percent of the
energy of the Universe was released within the first year after the
Big Bang itself. 

     The FIRAS also showed that the temperature of the afterglow of
the radiation from the Big Bang some 15 billion years ago has cooled
to 2.726 degrees above absolute zero, with an uncertainty of only 0.01
degrees.  At the moment of the Big Bang, the temperature of the
Universe was trillions upon trillions of degrees. 

     The DMR instrument detected the primordial hot and cold spots in
the Big Bang radiation.  The cold spots show denser matter that could
condense into huge clouds of galaxies.  Hot spots were thinner regions
that eventually contained no galaxies. Scientists hailed these
findings because this first detection of primordial seeds will form
the basis of scientist's understanding of how matter was able to form
into galaxies, clusters of galaxies and superclusters of galaxies and
huge empty spaces devoid of galaxies. 

     The hot and cold spots found by COBE are only 30-millionths of a
degree -- one part in 100,000 -- warmer or colder than the regions
next to them.  The COBE results show that these seeds are truly
primordial and were present just 300,000 years after the Big Bang.