National Aeronautics and Space administration officials are preparing the Mariner D spacecraft for launch on a Mars trajectory within the current launch opportunity. The launch of Mariner D, now undergoing final checkout at Cape Kennedy, has awaited analysis of the failure of the Mariner 3 mission launched November 5.
If current tests of Mariner, its Atlas/Agena launch vehicle, and the aerodynamic fairing protecting the spacecraft during powered flight goes well, Mariner D will be launched no earlier than November 27.
After a detailed analysis of the Mariner 3 launch project officials concluded that the fairing did not completely jettison as scheduled some 5 1/2 minutes after launch. The spacecraft could not deploy its solar panels and its battery was drained about 9 hours after launch.
Investigation indicated that the fairing, made of a light weight fiberglass, laminated, honeycombed structure, probably had a structural failure when exposed to the flight environment. This prevented shroud separation from the spacecraft.
As a result, a decision was made to design and fabricate a metal shroud section to replace the fiberglass section. This work is being done under direction of NASA's Lewis Research Center, Cleveland, at Lockheed Missile and Space Company, Sunnyvale, California, on a 24-hour-day, 7-day-week schedule. One metal shroud, made of a light weight magnesium alloy, has been completed and is now being tested by Lockheed. A second metal shroud is currently being fabricated.
If the testing goes well, it is planned that the first of the metal shrouds will be shipped to Cape Kennedy this weekend so that all system checks can be conducted on the spacecraft/ launch vehicle combination at Complex 12 next week.
The Lewis Center also has ordered removal of the command destruct system from the Agena second stage of the launch vehicle. The command system is being replaced by a self destruct system. This is similar to the Atlas/Agena configuration which launched the first six Rangers and the first two Mariners. This modification, which reduces the weight of the Agena by about 30 lbs., could gain a few days in the current Mars launch opportunity. It could also off-set the slightly increased weight -- about 50 lb. -- resulting from the proposed switch to a metal fairing.
Current launch opportunity for Mars opens November 4 for about a one month period. The rapid failure analysis and resulting modifications were necessary because a Mars launch opportunity occurs only once every 25 months. Failure to launch in 1964 would mean either cancellation of the Mariner D or a two year storage period with a launch attempt in 1966.
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: A.M.'s of Friday, August 21, 1964
The National Aeronautics and Space Administration will launch two Mariner space vehicles in the fourth quarter of this year to begin the first step by the United States in the exploration of Mars with unmanned spacecraft.
This is the most complex mission to be attempted to date in the U.S. unmanned space program.
Objectives for these first Mariners will be to explore interplanetary space between Earth and Mars and to validate new engineering techniques that will be used for the first time in this mission.
The decision to launch two spacecraft on the same mission was dictated by the difficult engineering task that the Mars mission represents and by the necessity of utilizing untried engineering advancements to achieve any probability of success.
The two Mariners will be prepared simultaneously on separate launch pads because of the relatively short opportunity for a Mars launch. The second spacecraft will be launched as soon as practical after the first. The period in which a spacecraft can be launched to Mars lasts only a few weeks and occurs only once every 25 months.
An Atlas-D/Agena-D combination will be used to launch the Mariners. Maximum performance demands have been placed on these vehicles for this mission.
Management and technical direction for the Mariner Project is assigned by NASA's Office of Space Science and Applications to the California Institute of Technology Jet Propulsion Laboratory. This includes responsibility for the spacecraft, space flight operations, and deep space tracking and communications. The Atlas/Agena launch vehicles are under direction of NASA's Lewis Research Center, Cleveland, and will be launched by Goddard Space Flight Center's Launch Operations from Cape Kennedy, Florida.
Interplanetary scientific equipment on the Mariners will report on radiation, magnetic fields, and micrometeorites.
If either Mariner is functioning at planet encounter, planetary experiments will return television pictures and other measurements of the planet.
Future exploration of Mars will require landing an instrumented capsule on the surface to perform biological experiments. Designing a capsule, however, requires accurate information on the density of the Martian atmosphere. Current scientific estimates vary over a wide range.
Therefore, an attempt will be made to make a measurement of the Martian atmosphere in the Mariner-Mars 64 mission.
This will be accomplished by selecting a spacecraft trajectory that will cause the spacecraft to pass behind Mars and to be occulted from Earth. Prior to occultation the tracking signal transmitted from the spacecraft will pass through the Martian atmosphere. The effects of the atmosphere on this radio signal will yield information on the varying density of the Martian atmosphere. One or both of the Mariners may perform this experiment.
It is expected that the proximity of Mars to the asteroid belt may produce a higher incidence of micrometeorites than was the case in the flight of Mariner II from Earth to Venus in 1962. Part of the exploratory nature of the first Mars mission will be to determine if micrometeorites constitute a serious hazard in flights to Mars.
The first Mars mission will also yield important data on space navigation over tremendous distances and on the capability of powering a spacecraft by converting sunlight to electricity during a mission in which the Sun-spacecraft distance is steadily increasing. The Mars Mariners will be equipped with four solar panels as compared with two for Mariner II and the Ranger lunar impact spacecraft.
Unprecedented distances in space are involved in this mission. At launch, the Mariners will be aimed along a trajectory between the orbits of Earth and Mars, which will be some 350 million miles long. At time of encounter, Mars and Earth will be about 150 million miles apart.
The Mariner Mars spacecraft will weigh approximately 570 pounds with a span of 22 feet, panel extended, and a height of 9-1/2 feet. Flight times vary, relative to day of launch, from 7-1/2 months to 8-1/2 months with an additional three weeks of flight beyond the planet needed to return data.
This mission will utilize the following technical advancements for the first time:
1. High frequency radio communication. The communication distance of more than 150 million miles. This compares with 53.9 million miles achieved for the 1962 Mariner II Venus mission.
2. A midcourse guidance rocket engine that can be fired twice. Earlier spacecraft have not had a re-start capability.
3. First use of the Agena-D second stage and first use of the Atlas-D with many improvements.
4. First use of the star Canopus for spacecraft attitude reference.
The long duration of the mission requires that the Mariners survive in space for a minimum of nine months. The longest previous life-time requirement for a U.S. deep space probe was 3-1/2 months for the Mariner II Venus mission.
The nine-month flight requirement is applied to some 138,000 component parts for the Mariner Mars spacecraft compared with 54,000 component parts for the Mariner II.
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