imp-c press kit

8/8/2019 IMP-C Press Kit

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NAllI)NAL AEROrJALJII(S AND SPACE ADMINISTRATION TELS WO2--4t55WASHING TON, D ( 20'46 WO 3-6925

w FOR RELEASE: MONDAY AMISF May 24, 1965RELEASE NO: 65-164

PROJECT: c

CONTENTS

GENERAL NEWS RELEASE. ..... . . . . . . . *. , 3


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NATIONAL AERONAUTICS AND SP/..E ADMINISTRATION TELS WO 2-41- -ASHINGTON, D.C. 20546 WO 3-69FOR RELEASE: MONDAY AM' SMay 24, 1965RELEASE NO: 65-164

NASA WILL LAUNCHTHIRD INTERPLANETARYMONITORING PLATFORM4

The third in the Interplanetary Monitoring Platform(IMP) series of Explorer satellites is mheduled for launchby the National Aeronautics and Space Administration no


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The new satellite, IMP-C, will bf c launched by a thrce-stage Delta. The highly elliptical orbit is planned to beinclined 33 degrees to the Equator and to take the satellite130,000 miles into interplanetary space and a. close toEarth as 120 miles. About four days will be required forthe 130-pound satellite to complete an orbit.

The spacecraft contains nine experiments by scientistsfrom the universities of California, Berkeley, and Chicago,


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The IMP studies complement thc Scientific objectives cIf

to the development of' Solar flare prediction capability whilch

will be uoeful to the NASA Apol~o manned Moon landing progrcmi.


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THE IMP SATELLITE

The IMP-C is a compact 130-pound physics laboratory.It has an octagon base, eight inches high and about 28 inchesin diameter. All but two of its experiments are mounted Inthis eight-sided base.

Magnetometers, which measure magnetic fields in space,have been mounted to avoid interference froma the weak magnetic


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LAUNCH WINDOW

The period during which the launch can be made (launchwindow) is calculated to take full advantage of the gravitationalinfluences of the Earth, Moon and 3un on the spacecraft. Thewindow is limited to about a one-hour period on certain daysof the month.

SCIENTIFIC OBJECTIVES

As were the earlier IMP satellites, the primary objectives


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1. The rubidium-vapor magnetometer, a five-pound ball-shaped device, 13 inches in diameter, mounted six.eet above the satellitests main structure.

2. Two fluxgate magnetometers, mounted on seven-footbooms attached to the base of the satellite.

The experiments accurately measure magnitude anddirection of the magnetic field in space. The informationobtained is of value in determining the physical state of


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-7-The two fluxgate magnetometers are to measure the

direction of weak magnetic fields. The instrumentation iscomplementary in that the rubidium vapor magnetometer permitsthe calibration of the zero levels of the fluxgate magnetometersin flight.

The dynamic range of the fluxgate sensors is 4 40 gamma(1 gamma = 10-5 gauss) with an accuracy of + .16 gammas.The dynamic range of the rubidium vapor magnetometer is 0.1gammas to 1000 gammas. The magnetic field strength nearthe Earth varies from 30,000 gammas at the equator to about70,000 gammas at the poles.


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-8-in detail the particle energies resulting from solarflares which may occur during the satellite's lifetime.It will also look for low energy trapped protons in theEarth's magnetosphere. (Prepared by the ITniversity ofChicago.)

2. Two pancake-shaped geiger counters--called particletelescopes--are to obtain data on direction and flux ofcosmic rays produced by large solar flares. With thisdata, it is hoped an integrated idea of interplanetary


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-9-4, An ion chamber to measure the presence of protonradiation and determine its quantity in terms of adose rate of roentgens per hour. Changes in intensityof cosmic radiation caused by flare activity also willbe recorded. (Prepared by the University of California.)

Another experiment being flown consists of two geigercounter tubes to~detec-t fluxes oi 1 electrons with an energyabove 40,000 electron volts. Electrons of this energy playan important role in many geophysical phenomena. Informationon this flux helps determine the Sun's role in supplying


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by admitting them through a sltt of known dimensionsin the side of the satellite. (Prepared by the NASAAmes Research Center.)2. Another way to measure the solar wind is with adevice which will permit particles to enter a six-inch-diameter surface through a series of grids that separateelectrons and low-energy positive particles. Thisinstrument will determine flux, speed and direction ofthe particles analyzed. (Prepared by the Massachusetts


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SCIENTIFIC FINDINGS OF EXPLORER XVIII

The experiments carried into space by the first IMP,Explorer XVIII, have given the scientific community valuablenew information.

Of special significance have been the studies of theboundary or transition region between the Earth's magnetosphereand interplanetary space.

The magnetosphere is the envelope formed by the Earth's


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- 12 -Mapring of these regions by Explorer XVIII's

magnetometers shows that the shock wave and the turbulenttransition region trails back and away from the Earth inincreasingly widening bands, much in the manner of the wakeof a ship at sea. This "wake" of particles in lessening intensity,may extend as far back as a quarter of a million miles, or more.

Another important Explorer XVIII discovery was madeDec. 14 and 15, 1963, when the satellite was near apogee duringits fifth orbit. Its magnetometers registered significant


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-13 -More than 5,600 hours Of scientific data were provided

by Explorer XVIII before its transmission became intermittentin May 1964. A few hundred more hours of data were receivedbefore monitoring of the satellite ceased a year later.

The second IMP, Explorer XXI, was launched Oct. 4, 1964.It was short of its planned orbit, but has provided added dataon the magnetosphere.


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Cosmic Ray Experiment - Range versus energy lossDr. J. A. Simpson, EnricoFermi Institute, Universityof ChicagoCosmic Ray Experiment - Energy versus energy loss

Dr. Frank B. McDonald andDr. George Ludwig, GoddardSpace Flight CenterCosmic Ray Experiment - Orthogonal Geiger CounterTelescopeDr. Frank B. McDonald andDr. George Ludwig,

Goddard Space Flight CenterCosmic Ray Experiment - Ion chamber and geiger countertubesDr. Kinsey A. AndersonUniversity of CaliforniaSolar Wind Experiment - Low energy proton analyzer


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FACT SHEET(IMP-C)

Launch: On or about May 28, 1965Eastern Test Range, Cape Kennedy, onDelta rocketApogee: 130,000 statute milesPerigee: 120 statute milesInclination: 33 degreesPeriod: About four daysVelocity: 24,300 mph at perigee780 mph at apogee


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- 17 -Voltage: 11.5 to 19.6 vdcPower: 38 watts

Communications and data-handling systemTelemetry: Pulsed-frequency modulation (PFM)Transmitter: Four-watt output at 136.125 mcsEncoder: PFM with digital data processor (DDP)for accmulation and storage of data

Tracking: Stations of the world-wide SpaceTracking and Data Acquisition Network(STADAN) operated by the Goddard SpaceFlight CenterData-AcquisitionStation: Johannesburg, South AfricaWoomera, AustraliaSantiago, Chile


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The Delta vehicle has the following general characteristics:Height: 90 feetMaximumn Diameter: 8 feetLift-off Weight: About 57 tons

First Stage: Thor space booster, produced by DouglasAircraft Co.Propellants: Liquid (Kerosene with liquid oxygenas oxidizer)Thrust: 170,000 poundsBurningTime: About two minutes and 25 seconds


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During first and second stage powered flight, the BellTelephone Laboratory radio-guidance system is used for in-flight trajectory corrections. It also commands second-stagecutoff when the desired position, velocity and altitude havebeen achieved.

Following second stage cutoff, a 32-second coast periodoccurs. During this period, small rockets mounted on a tablebetween the second and third stages ignite and spin up thethird stage and the satellite to the desired spin rate. The


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MOON'S WAKE ENCOUNTERED BY IMP

WIM P ENCOUNTER>X\\\\X\\\\Koi\ \ \\OUTER BOUNDARYa\\\ Ae3wP-P\ IMP ORBITw\ OF EARTH'S

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