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OFFICE OF PUBLIC EDUCATION AND INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
FOR IMMEDIATE RELEASE:
A command was radioed to the Mariner IV spacecraft
Sunday, Dec. 13, at 6:09 A.M. PST from the Goldstone tracking
station of the Deep Space Net ordering the spacecraft to switch
power amplifiers in its radio transmitter. The spacecraft trans-
mission was interrupted for 90 seconds until the new power tube
completed its warm-up at which time communications from Mariner
were continued.
Mariner was designed with two types of power amplifiers
to provide redundancy. A cavity amplifier has been in use since
launch. The switch over was made to a traveling wave tube ampli-
fier. The traveling wave type can provide more transmitting
power, an increase from 6 1/2 watts to 10 1/2 watts and is
expected to have longer life.
If required, the transmitter can be switched back to
the cavity amplifier.
The traveling wave tube was not used during launch
because it operates at a high voltage level and presented a
possibility of high voltage arcing. High voltage devices will
arc during the launch of a spacecraft in an area of low
atmospheric pressure between 150,000 to 250,000 feet.
The switch over was made at this time to take advantage
of the current high transmission bit rate from the spacecraft of
33 1/3 bits per second. Because of the increasing distance of
-2-
the spacecraft from earth the bit rate will be automatically
switched to 8 1/3 bits per second on Jan. 3, 1965.
All systems aboard Mariner are functioning normally
with the exception of the solar plasma probe.
Distance from earth at 6:00 A.M. Dec. 13 - 2,580,240
Sun based velocity - 73,567
Earth based velocity - 6,961
OFFICE OF PUBLIC EDUCATION AND INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
FOR IMMEDIATE RELEASE:
Two commands from Earth were transmitted to Mariner IV
today, Dec. 17, both of them intended to cause the spacecraft's
attitude control system to fix and remain on the star Canopus.
Light from the star Gamma-Vela had held the tracker's
attention since Dec. 7 when Canopus lock was lost and the Mariner
went into its programmed roll search.
The first of today's commands called a DC-21, was trans-
mitted at 8:00 a.m. PST and commanded the tracker to break lock
with Gamma-Vela and go into roll search for Canopus. Canopus was
reacquired at 8:03:02 a.m. PST.
The second, DC-15, was sent at 9:30 a.m. PST. The
function of this command was to prevent the spacecraft from
losing its lock on the star Canopus. This has occurred several
times during the mission and is believed to be caused by dust
particles drifting in front of the sensor and reflecting a flash
of sunlight into the sensor. A particle 1/3 the diameter of a
human hair and two feet in front of the Canopus sensor, results
in a light intensity sufficient to cause loss of lock and initiate
roll search. DC-15 should make the sensor less sensitive to such
particles.
Both commands were prepared in the Space Flight Opera-
tions Facility, Pasadena, Calif., and transmitted from NASA's Deep
Space Net station at Woomera, Australia.
-2-
In its first 19 days since launch, Mariner IV has made
six and 1/2 million measurements in space outside the Earth's
orbit.
MARINER IV ORBITAL ELEMENTS
Period - - - - - - - - - - - - - - 529.28308 days
Semi-major Axis - - - - - - - - - 191,566,820 km.
Eccentricity - - - - - - - - - - - .23006229
Longitude Ascending Node - - - - - 68.484947 deg.
Argument of Pericenter - - - - - - 352.70981 deg.
Inclination to Ecliptic - - - - - .12858524 deg.
Epoch at Perhelion - - - - - - - - 7 Dec. 1964 - 10 hrs.
22 min. 32.6 sec.
Perihelion Distance - - - - - - - 147,494,520 km.
Aphelion Distance - - - - - - - - 235,639,120 km.
Time of Osculating Conic - - - - - 7 Dec. 1964 - 10 hrs.
22 min. 32.6 sec.
ESTIMATED POST-ENCOUNTER ELEMENTS
Period - - - - - - - - - - - - - - 569.80421 days
Semi-major Axis - - - - - - - - - 201,223,510 km.
Eccentricity - - - - - - - - - - - .16861905
Longitude Ascending Node - - - - - 226.89873 deg.
Argument of Pericenter - - - - - - 200.17315 deg.
Inclination to Ecliptic - - - - - 2.9785797 deg.
Epoch at Perihelion - - - - - - - 6 June 1966 - 21 hrs.
24 min. 44.5 sec.
Perihelion Distance - - - - - - - 167,293,390 km.
Aphelion Distance - - - - - - - - 235,153,620 km.
(Continues above Ecliptic after Encounter)
Time of Osculating Conic - 1 Oct. 1965 - 16 hrs. 09 min.
25 sec.
Office of Public Education and Information
12/29/64
OFFICE OF PUBLIC EDUCATION AND INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
FOR RELEASE THURSDAY, JANUARY 7, 1965
The amount of information transmitted to Earth each
second by the Mars-bound Mariner IV was changed this week by an
automatic switching event aboard the spacecraft.
At 8:59 a.m. PST Sunday, Mariner's central computer and
sequencer switched the telemetry bit rate from 33 1/3 bits per
second to 8 1/3 bits per second. The new rate will remain in
effect for the duration of the 228-day mission. The rapidly
increasing communications distance requires the slower
transmission of data.
At 6 a.m. PST today, Mariner will have travelled more
than 70 million miles in its 325-million-mile flight to Mars. At
the same time, distance between Earth and the spacecraft will be
6,906,935 miles.
Project officials at the Jet Propulsion Laboratory in
Pasadena, Calif., reported that all spacecraft systems are operat-
ing normally after 40 days in space. JPL manages the Mariner
project for the National Aeronautics and Space Administration.
The following five science instruments have been
collecting data in space since November 28, 1964, when Mariner IV
was launched from Cape Kennedy:
Helium vector magnetometer, which investigates inter-
action between planetary and interplanetary magnetic fields and
will determine if Mars has a magnetic field. Scientific investi-
gators are Dr. J. Edward Smith, JPL; Paul J. Coleman Jr., Uni-
-2-
versity of California at Los Angeles; Prof. Leverett Davis Jr.,
California Institute of Technology; and Dr. Douglas E. Jones,
Brigham Young University and JPL.
Cosmic ray telescope, which detects and measures cosmic
rays by type, energy levels and direction of motion. Experi-
menters are Dr. John A. Simpson and Joseph O'Gallagher, University
of Chicago.
Cosmic dust detector, which measures cosmic dust part-
icle momentum and distribution near Earth, in interplanetary space
and near Mars. Experimenters are W. M. Alexander, O. E. Berg, C.
W. McCracken and L. Secretan, all of NASA's Goddard Space Flight
Center; and J. L. Bohn and O. P. Fuchs, both of Temple University.
Trapped radiation detector, which makes radiation measure-
ments in interplanetary space and will determine whether Mars has
trapped radiation belts similar to Earth's Van Allen belts. Experi-
menters are Dr. James A. Van Allen, Dr. Louis A. Frank and Stamatios
M. Krimigas, all of the State University of Iowa.
Ionization chamber, which measures charged-particle
intensity and distribution in interplanetary space and in the
vicinity of Mars. Experimenters are Prof. H. Victor Neher,
Caltech., and Dr. Hugh R. Anderson, JPL.
Two additional experiments will occur after Mariner IV
encounters Mars next July 14.
A single television camera will take black-and-white,
still pictures of the Martian surface. Experimenters are Prof.
R. B. Leighton, Prof. R. P. Sharp and Prof. B. C. Murray, all of
Caltech.
-3-
The occultation experiment will determine density and
scale height of the Martian atmosphere. Experimenters are Dr.
Arvydas J. Kliore, Dan L. Cain and Gerald S. Levy, all of JPL;
Prof. Von R. Eshelman, Stanford Electronics Laboratory; and Prof.
Frank Drake, Cornell University.
One of Mariner's eight scientific experiments ceased to
function on Dec. 7, 1964. This was the solar plasma probe, which
for the first 10 days of the mission measured the intensity of low
energy protons from the sun. Experimenters are Prof. Herbert L.
Bridge and Dr. Alan Lazarus, Massachusetts Institute of Tech-
nology; and Dr. Conway W. Snyder, JPL.
####
OFFICE OF PUBLIC EDUCATION AND INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA TELEPHONE 354-5011
FOR IMMEDIATE RELEASE FRIDAY, FEBRUARY 5, 1965
A solar flare, described as one of medium intensity,
was detected today by the Mariner IV spacecraft en route from
Earth to Mars.
Telemetry from Mariner, via the Johannesburg, South
Africa, tracking station of the Deep Space Network, was received
as the flare occurred by scientists and engineers at the Jet
Propulsion Laboratory in Pasadena, California.
Interplanetary science instruments aboard the
spacecraft showed huge increases in measurements of solar
radiation shortly after 10 a.m. Pacific Standard Time.
Occurence of the "class-two" flare, unusual during a
quiet sun period which currently exists, was confirmed at noon
today by contacting the Solar and Geomagnetic Monitoring Service
at Fort Belvoir, Virginia.
The solar storm is expected to continue for several
days. When the flare occurred, Mariner IV was 14.5 million miles
from Earth and 106 million miles from the sun.
-0-
OFFICE OF PUBLIC EDUCATION AND INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
FOR RELEASE FRIDAY, FEB. 5, 1965:
After nearly 10 weeks in space, the Mars-bound Mariner
IV spacecraft still is performing normally, the National Aero-
nautics and Space Administration announced today.
Telemetry radioed from the spacecraft to the Space
Flight Operations Facility at the Jet Propulsion Laboratory
indicates that all systems, with the exception of the solar
plasma probe, are operating properly.
The solar plasma probe, one of eight scientific experi-
ments aboard Mariner IV, ceased to return intelligible data last
December 7, ten days after the spacecraft was launched from Cape
Kennedy.
At 9:00 a.m. EST today, Mariner IV was 14,421,246 miles
from Earth and had travelled more than 117 million miles in its
sun-circling orbit. It was moving at a velocity of 14,478 miles
per hour relative to Earth and 65,670 miles an hour relative to
the sun.
When the spacecraft makes its closest approach to Mars
- some 5,000 miles from the planet - next July 14, its total
mileage in space will have exceeded 325 million miles.
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