flight report - interplanetary monitoring platform imp-ii (explorer xxi)

8/7/2019 Flight Report - Interplanetary Monitoring Platform IMP-II (Explorer XXI)

1/33

N A S A T E C H N I C A L N O T E -N A S Ae-

F L I G H T R E P O R TI N T E R P L A N E T A R Y M O N I T O R I N G P L A T F O R MI M P - I 1 ( E X P L O R E R X X I )

by Frank A. CarrGoddurd Spuce Flight CenterGreenbelt, M d .

TN D - 3 3 5 3.- ..--

N A T I O N A L A E R O N A U T I CS A N D SPA CE A D M I N I S T R A T I O N W A S H I N G T O N , D. C. J U N E r966


2/33

TECH LIBRARY KAFB, NMIIllill1111111llllI8lllllI1Ill. . OL305bbNASA TN D-3353

FLIGHT REPORTINTERPLANETARY MONITORING PLATFORM

IMP-I1 (EXPLOR ER XXI)By F r a n k A . C a r r

Goddard Space Fl ight Cente rGreenbe l t , Md.

N A T I O N A L A E R O N A U T IC S A N D S P A C E A D M I N IS T R A T I O NFor sale b y the Clearinghouse for Federal Scientific and Technical Information

Springfield, Virginia 22151 - Price $2.00


3/33

ABSTRACTIMP 11 was launched on October 3, 1964 from Cape Kennedy,

Flo rida , by the Delta 26 Launch vehicle. The apogee achieved w a s51,600 n.m., which was l e s s than one-half of the planned alt itude. Th isproblem w a s attributed to the suspected failure of the igni ter assemblyof the third-stage motor, occur ring after about 16 seconds of no rmalburning.

The angle between the space craft spin-axis and the ecliptic planewas reduced by the third-s tage malfunction, resulting in a wider rangeof incident sun-angles during the sa tellite lifetime . Thi s caused lowpower output from the so lar paddles and over-heating of the silver-cadmium battery.

Spacecraft perform ance was satis factory until the +50 "C temper a-tu re environment (about two months afte r launch) caused the fai lure ofthe battery. The rea fter , the spacecr aft operated only during peri ods offavorable incident sun-angles. In all, about five months of useful datawas recorded. A s of mid-1965, the spa cecra ft was operating inte rmi t-tently with esse ntia lly no useful data being obtained. Th er e is somepossibility that perh aps as much as a month's mo re data might be'ob-tained in the futur e.

ii


4/33

CONTENTS

Abstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiINTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1MISSION OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1LAUNCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2THIRD STAGE PERFORMANCE . . . . . . . . . . . . . . . . . . . . . 3ORBIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4ATTITUDE AND SPIN RATE . . . . . . . . . . . . . . . . . . . . . . . 4SPACECRAFT PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . 7PERFORMANCE PARAMETER IN-FLIGHT DATA . . . . . . . . . 8

In-Flight Temperatures. . . . . . . . . . . . . . . . . . . . . . . . . 9Powe r System Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

BATTERY PROBLEM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16CONCLUDING REMARKS . . . . . . . . . . . . . . . . . . . . . . . . . . 18References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

19ppendix A-IMP-I1 Spa cecr aft Operational Pe ri od s. . . . . . . . .Appendix B-IMP-I1 Per for man ce Pa ra m et er Data Teleme teredor Observed Values (Uncorrected) (From QuickLook Tape s). . . . . . . . . . . . . . . . . . . . . . . . . . . 23Appendix C-IMP-I1 Per for man ce Pa ra me te r Data Corr ected 25Appendix D-IMP-I1 Shadow Tim es . . . . . . . . . . . . . . . . . . . . 27

for Analog Oscillator (AO) Calibration Drift . . . . .

iii


5/33

FLIGHT REPORTINTERPLANETARY MONITORING PLATFORMIM P-I I [EXPLORER XXl]

byFrank A. Carr

Goddavd Space Flight Centev

INTRODUCTIONThe I M P ser ies is a continuation and an outgrowth of the success ful ser ie s of GSFC Explorer

sat elli tes including X, X I , X I V , and XV. IMP-I, launched on 26 November 1963, atta ined an apogeeof 106,000 n.m., which carr ied it well into interpla netary space. The spacecraft operated suc-cessfully for more than six months (Reference 1) telemetering a wealth of data. The scienti ficexperiments on IMP - I (Explorer XVIII) provided the first di re ct evidence of a collisi onless mag-netohydrodynamic shock wave surrounding the e art h and its magnetosphere. The spacecraf t alsoprovided many da ta on the na ture of t he transit ion region between the magnetopause and shockfron t; i.e., the magnitude, direct ion, and vari ations of the inter plan etar y magnetic field, and on theenergy and fluxes of th e so la r wind and so la r and cosmic r a y s (Reference 2).

IMP-11, launched slightly more than ten months after the first I M P , carri ed the sa me typeexperiments, but which i n many ca se s we re updated and refined, based on dat a obtained fromIMP-I .

MISSION OBJECTIVESThe miss ion objectives of IMP-I1 (Reference 3), s imi lar t o those of IMP-I, were (1) to study

in detail the radiation environment of cisluna r space, and to monitor this region ove r a significantport ion of a sol ar cycle; (2) to study the quiescent prop erti es of the interpl anetary magnetic fieldand its dynamical relationship with particle fluxes fr om the sun; (3) to develop a solar flare pre-diction capability for Apollo; (4 ) to extend knowledge of so lar t er re st ri al relat ionships ; and(5 ) to furthe r the development of relative ly inexpensive spin st abilzed spac ecraft for interplane-ta ry inves tigations . Because of the achieved apogee of only 51,600 n.m., the pri ma ry objectives(i.e., monitoring of the interplane tary medium) we re not accomplished. However, the spa cec raf t'snine scientific experi ments provided many data fr om within the m agnetosphere which a r e expectedto cont ribute significantly to the unders tanding of th is reg ion.

1


6/33

LAUNCHThe IMP-B spac ecra ft was launched (F igure 1)on 3 October 1964 at 2245:00.4 EST (4 October

1964, 0345:00.4 UT). After a succes sful launch, it was redesignated as IMP-II.The Delta 26 launch vehicle, designated DSV-3C, consis ted of a Douglas Airc raft liquid propel-

lant Thor boost er, an Aeroje t General liquid propellant second stage, and an Allegheny Ballistic ssolid propellant thir d stag e. The 30-inch extended low drag aerodynamic fairing was used.

Fi rs t st age performanc e was above nominal, and second stage engine performance was goodbut with a slightly lower than nominal thr ust level achieved. First and second stage propellant

utilization was 99.7 and 97 percent r espe c-tive ly. At su st aine r engine cutoff (SECO), thevehicle velocity was within 3 ft/ sec of nominal.The spin rate at second/third stage separationwas 80.6 rp m (nominal was 72 *loo/, rpm) withsom e pitch and yaw motions due to the asym-metrical spin rocket arrangement. A mal-function of th e third stage occu rre d about 17seconds af ter ignition which res ulted in re-duced performance and considerable coningof the thi rd s tag e spac ec raf t configuration.*

Figure 1-IMP-I1 launching.

Beca use of the thi rd s tage malfunction,the injection velocity was 1.8 percent belownominal, and an apogee of only 51,600 n.m.(nominal was 110,000 n.m.) w a s achieved. Inaddition, the dynamic perturbations introducedby the malfunction caused a shi ft of the spac e-craf t spin axi s of about 78 degree s resultingin a wider range of incident sun angles whichin turn res ulte d in low power output from the

sol ar paddles and overhea ting of the spa cec raft battery.Orbit injection occurred at 0351:29.5 UT 4 October 1964 and at approximately 23.3 d egr ees

north latitude and 66.7 degrees west longitude from an initial azimuth of 108 de gr ee s out of Pad17A7 Cape Kennedy, F lor ida. Injection alt itude w a s 197 km, and velocity at injection was35,023 ft/sec.

The launch phase sequence of events oc cur red as planned (Table 1). Spacecraft telemet rydata, relayed fr om Ascension Island, confirmed, in real -tim e, so la r paddle erecti on and space-craft separation from the third stage.~- -*Delta 26 , Final Report, Goddard Launch Operations Division, GSFC, GLOR-137.

2


7/33

-

122,4576,883

35,65610,708

~~

Table 1Flight Sequence of Events* Delta 26, LMP-I1 3 October 1964

51,6002,097

35,023**10,081**

Event

LiftoffMECO (Main Engine Cutoff)Stage I1 IgnitionFair i ng EjectionSECO (Sustainer Engine Cutoff)Spin-UpSeparationStage 111 IgnitionStage 111 BurnoutErec t So la r PaddlesE r e c t F l u Gate BoomsSeparationFir e S tage I11 Tumble Rockets*Rrference 4 .t R a s e d on Doppler data.

THIRD STAGE PERFORMANCE

Seconds From LiftoffNominal

2245:OO EST148.56152.56182.56325.63361.56363.56367.56390.16451.6453.6458.6462

-~2_Actual

2245:00.4 EST144.59148.60180.05322.81357.60359.60363.17388.7t----

Following the fa ilur e of Delta 26 to inject IMP-I1 into the desi red o rbit, thorough ana lyses ofthe launch data were made. The resu lts are documented in References 4 and 5 respectively.

The nominal, predicted, and actual par ame ter s at third stage burnout (Reference 4) are givenin Table 2.

The effective velocity increment imparted by the third stage was five to s ix percent belownominal, which caused the tot al inj ection velocity to be about 1.8 percent low. Fo r an IM Pmissio n (Le., high orbit eccentricity ), a sm all change in injection velocity cause s a larg e changein apogee height (Figure 2).

Table 2IMP-II Parameters

Apogee (n.m.)Per iod (min)Velocity (ft/sec)Stage UI Velocity (ft/sec)

NominalDetailed T es t Objective 1 p I Actual(DTO)

110,0005,915

35,59110,708

*Base d on actual pos i t i on and ve loc i ty a t th ird s tage i gn i t ion plus nominal third st ag e performance,Bel l Te l ephone Labs .**Rec onstru cted from orbital eleme nts.

3


8/33

- I L- -. I -__-0.5% NOM INAL +O.5%V E L O C I T Y(35,600 f t lsec)Figure 2-Apogee alt itu de versus inj ect ion vel oci ty.

The difference in the velocity increme ntnoted above was due to reduced perfo rmanceand thrust misalignment occurring about 17second s after ignition. Tracking data indi-cated a decrease in acceleration after 1 6seconds of no rm al burning until burnout, whichwas two secon ds longer than predicted. A tburnout, automatic gain control (AGC) dataindicated that the third st age and spacec raftwere coning (Reference 5) .

The decre ase of a cceleratio n (or thrust)and the longer burn time suggest a decreaseof chamber pres sure . This, combined with theobserved coning motion and some ground testdata, leads to the hypothesis that a por tion ofthe igniter assembly broke under the s t ressesof a ccel erat ion and vib rati on and w a s ejectedthrough the thro at causing an asymmet ricalincrease in throat area (Reference 5 ) .

ORBITThe IMP-I1 spac ecra ft was launched with the line of apsides extending toward the sun, but

inclined about -20 degr ees to the ecliptic. The initial orbit parame ters and those occurring atselected times a fter launch a r e shown in Table 3.

The time of launch was selected to provide, among other things, an increas ing perigean alti-tude. After si x months in orbit, perig ee had climbed from about 200 km at injection to ov er1000 km. The orbit lifetime has been calculated (December, 1964) to be slightly mo re than 25months with re -en try predic ted durin g mid-November, 1966.

ATTITUDE AND SPIN RATEThe orientation of the spac ecra ft spin axis, actual and nominal, is given in Table 4*.

The spacecraft spin axis in inertial space is parallel to a line drawn f rom th e point specified(actual) through the cen ter of the ea rth . The included angle between the me asur ed value andthe nominal value w a s 78.2 deg ree s and repr ese nts the total angular displacement of th e spin axis

__*GSFC memo f rom E . J. P y l e , IMP-B Spin Axis Orientation, 6 November 1964.

4


9/33


10/33

Table 4IMP-II Spin Axis Orientation

fr om nominal. The effect of thi sattitude perturbation was to decr easethe angle between the spin axis andthe ecliptic plane. Hence, the rangeof s pin axis-sun ang les was extendedbeyond nominal limits.

Right AscensionDeclination

7 October 1964 1 The spacecraft entered sunlightliftoff. The initial optical aspect da ta indicated that the spac ecra ft was coning with the s pin axis-sun angle varying fro m about 125 o 130 degrees. The observed spin rate was 14.58 rpm at T + 21minutes. The nominal orbi tal spin rate should have been 23 rpm assuming an ini tial spin-up of80 rp m and norm al erecti on of appendages. The fact that the spacecraft achieved an initial orbitalspin rate of 14.58 rp m ha s not been explained satisfactor ily.

approximately twenty minutes after

Following separat ion of th e spacecraft from the third stage, the coning motion of the space-cra ft damped out and the observed spin rate decreased to 14.25 rp m (four and one-half days aft erlaunch). The spin rate subsequently i ncre ased due to s ola r radi ation pre ss ur e when the incidentsunlight was below t he spac ecra ft equator and decre ase d when the sun was above the equator(Figure 3). The spin axis-sun angle (F igure 3)was about 130 degre es some eight hours afterlaunch (nominal was 105 degrees) and progressing further from the spacecraft equator, ultimatelyreaching a maximum value of 147 degr ees (nominal for the specified launch time w as 135 degrees).

I I I I I I I I1 - CTUAL ~EXTRAPOLATED -I ------ 19

1817

16 -Ea15 2E4,14 5a)

I3

I2

11

0

d.III

' +.i l

1

I_ _ _iI220 2

I 1

1260 270 280 770 180 190 200

~ A ~ R I L 1 1 Ii 1 J U LYII J A N . 65 11 1 N 'G. 1 PT :T.0 C T . 1964 1 NOV. 1 DEC.LA U N C H DAYS AFTER LAUh

Figure 3-Spin axis-sun angle and spin rate versus tim e.

6


11/33

SPACECRAFTPERFORMANCENotwithstanding th e "Mission Fai lur e" l abe l applied to IMP-I1 because of the insufficient

apogee altitude, the spa cec raft did, in fact, provide useful data during its travels within themagnetosphere. While its apogee a lti tude was only half of its immediate predecessor IMP-I , itexceeded and equaled respectively, the altitude of its forerunners, Explorers XI1 and XIV.

In addition to a low apogee, the launch malfunction indirectly caus ed the fa ilu re of the space-cr af t batte ry. Symptoms of the failure began to appear som e 57 days after launch as the batteryproved incapable of susta ining spacec raf t operat ion within the shadow of the eart h. By 63 daysafter launch, the ba tte ry had failed completely (but in a fail safe mode). Therea fter, the space-cra ft would operat e (Figure 4 and Appendix A) only during pe riods of favora ble incident sun angles.However, each time the spacecraft entered a shadow, it would tu rn off fo r th e (nominal) 8-hourrecycle period.

Under these conditions, the spa cec raft trans mit ted 56 days of da ta during the 59-day pe riodbeginning 12 December and ending 9 Fe brua ry 1965, and 28 days of d at a during the 32-day per iodbeginning 5 March and ending 5 April 1965.

During a th ird period of favorable sun angles (July, 1965) signi ficant quanti ties of da ta we renot obtained. The reason for this is not known at th is writing, but de creas ed paddle output due toradiation damage is a possibility.

Throughout the per iods of operat ion (app roxima tely five months) all experiments and space-craft syst ems performed satisfactorily. No fail ures have been reported by any experime ntersalthough all da ta have not yet been analyzed.I 1964 I 1965I OCT. I NOV. I DEC. I JAN. I FEB. I MAR. I APR. I MAY. I JUNE 1 JUL. I AUG. I SEPT. I OCT.

~~

I-1ATISFACTORY OPERATION\\\- INTER MlnENT OPERATION

NOTES:0 OCTOBER 1964- LAUNCH (EXPLORER XXI, SUMED AS SU N-A NG LE REACHED A FAVORABLEDELTA 26). POSITIO N.

POOR SUN-ANGLE.@a@ U N D E R - V O L TA G E T U R N - O F F S DUE TO @ 13 - 18 DECEMBER-UNDER-VOLTAGETURNOFFS( 4 ) EAC H TIME THE S/C ENTERED THE EARTH'S@-@ UNDER - VOLTAGE TURN - OFFS WHILE IN0 5 DECEMBER THRU 12 DECEMBER- INTERMITTENT

SHADOW AT PERIGEE.ORBIT.0 4 FEBRUARY 196 5-S /C TELEMETRYSPURIOU SLYCOMMA NDED OFF; 23 1/ 2 HOURS OF DATALOST BEFORE TELEMETRY WAS COMMANDED ON.

EARTH'S SHADOW. @ 1 8 DECEMBER-S/C ENT ERS IW/OUNLIGHTOPERATION DUE TO FAILURE OF S/C BAl lERYCAUS ED BY EXCESSIVE TEMPERATURE.@ 13 DECEMBER- SATISFACTORY OPER ATION RE -

Figure 4-IMP-I1 status of operation.

0 FEBRUARY - NTERMITTENT OPERATION RE -SUMED AS SUN -ANGLE BECAME UNFAVORABLE;DURATION OF " O N " PERIO DS WERE LESS TH AN5 MINUTES UNTIL 3 MARCH.13 5 MARCH - SAME AS @) ABOVE.14 5 APRIL - INTERMITTENT OPERATION RESUMEDAS SUN - ANGLE BECAME UNFAVORABLE.OF OPERATION AS

7


12/33

On 4 and 5 Feb rua ry 1965, the spacecr aft signal was lost for 23-1/2 hour s. It was deter-mined tha t the tran sm it te r had been commanded-off by an unknown sour ce. Fortunately, re -activation occurr ed by command fro m Canarvonc about one-half hour pr io r t o the commencementof a sola r st orm . The spacecr aft transm itted continuous data throughout the s torm period beforeresum ing interm ittent oper ation sev era l days late r, due to unfavorable incident sun angles.

Several off period s which oc curred in ear ly April are suspected to be caused by sim ilar cir-cumstances, but it ha s not been pos sib le to dete rm ine the origin of th e off commands. On-boardproblems or respo nse due to commands intended for other spacecra ft are possibilities.

Because of the fail ure of the sp acec raf t batter y, the undervoltage-recycle p rog ram mer func-tion operated properly f or some 420 cycles as of 1 August 1965. The re cycle time, a nominal8 hours, proved to be quite consistent at about 7 1/4 hours.

PERFORMANCE PARAMETER IN-FLIGHT DATAOne of the 1 6 fr am es of th e telem etry fo rma t is allocated to the meas ureme nt of fifteen

analog performance par am ete rs (PP). Included are the measu remen t of fou r voltages, th ree cur -rents, seven tem per atur es, and one calibration point. About thir ty meas ure men ts of each pa-ram eter ar e made in one hour of operation.

Voltages MeasuredPP1 syst em voltage (19.6 volts, norma lly)PP2 prime converter + 50 vol ts &l%,egulated outputPP8 prime converter + 12 volts * l%,egulated outputPP12 multi-converter + 7 volts * l%, egulated outputCurrents MeasuredPP 3 battery charge curren tP P ~pacecraf t curren t (1.9 amps)PP9 sola r paddle output curren t

Temperatures Measured

PP 5 center tubePP6 Rb gas cellPP7 batteryPPlO sol ar paddle

.-*The tracking s tat ion s were unaware of IMP-11's off-on command capability since this was designed to be used only in the terminationof the spacec raft mission. Accordingly, they did not know that a normal range and range rate interrogation would reactivate the spa ce-craft transmitter. In thi s case , Canarvon i ssued a range and range r a te command on schedule, despite the fact that they had been un-able to acquire the spacecraft signal as i t came over the horizon. They reported, with some surprise, that they acquired the sp ace-craft telemetry immediately upon issu in g the range and range rate command.

8


13/33

Temperatu res Measured (cont 'd)PP13 Rb lampPP14 prime converterPP15 transmitter

The location of the voltage and curr en t se ns or s is shown relative to the IMP electricalsystem in Figure 5. The placement of the the rm ist or s is shown in Figure 6 .rqXPERIMENTTELEMETRYPAOOLES CONVERTER TRANS MIi7ER

DUMPINGCIRCUITRY CONVERTER

TO EXPiRIMENTS &OTHER SPACECRAFTI lNSTRUMENlATlON3"'"CURRENT SENSORVOLTAGE SENSORFigure 5-IMP-I I elect rical performance parameters.

Fr om anal ysis of the IMP-I1 PP data, aswell asIMP-I (Reference 1)andground tes t dataon IMP-type analog o scil lato rs, it is apparentthat the PP data dr if t following launch, reach-ing an e r r o r of about 2 or 3 percent after amonth or two of operation. The tel emete reddata in Appendix B have been analyzed and an

GAS CELL( PP6, C EN TERS P H E R E )

R b L A M P ( P P

OF

13 1

ADDLE ( INTERNA

NOT SHOWN:PR I ME C O N VER TER P P 14T R A N S M l l T E R P P 15Figure 6-IMP-I1 placement of thermistors.

appropriate correction factor assigned. The resulting adjusted data are shown in Appendix C.I t is estimated that the accu racy of the observed or telemetered data is *3 perc ent (frequencybasis) and the adjusted data +1 percent.

In-Flight TemperaturesDuring the perio ds of operation, mos t of the te mpe ratu res within the octagonal instru ment

compartment remained in the reg ion of + lo* to +60 "C (Fig ures 7 and 8). The tra ns mit ter (typi-cally a hot location) reached a maximum tempera tur e of +58"C about two months after launch; thebattery reached +50"C at about the sa me time, and the prim e conver ter reach ed a maximum of+39"C some s ix months af ter launch.

*Data mentioned herein are the adjusted data , i .e . , they includ e a correction factor fo r calibration drift.

9


14/33

. "T I "+6 0

+50

+ 40

+30g + mde +1 0

0

-uea+

E- 10-2 0

- 30

0 10 20 30 40 50 64 70 80 90 100 110L A U N C H t l N O V 6 4 t l DEC 64 t 1 JA N 65 t l R B 654 O C T 6 4 D A Y S A F E R L AU NC H

Figure 7-IMP-11 temperature data (not adjusted).

tOTE: D ATA HAV E NOT BEENADJUSTED FOR IN-FLIGHTCALIBRATION CHANGES-140

1 I 1150 160 170 180 1

0 10 20 30 40 50 60 70

I LL- 1 1 1- t t %f l 1 4 I1 1 P P 15

I P P 10i i ir i il l

NOTE:

t 1 M AR 65 t l AP R 65

DATA HAVE BEENADJUSTED FOR IN-FLIGHTCALIBRATION CHANGES- 1 1 1 1

t l FEE 65 t 1 M A R 65 t l AP R 651 JA N 65A U N C H t l N O V 6 4 t l DEC 644 OC T 64 D A Y S A F E R L A U N C HFigure 8-IMP-I I temperature data (adjusted).

10


15/33

, , I m . 1 1 . . . 1 1 1 - . - . 1 1 1 ,LE--

,,,, . . . ,. - , .,.,...-, * 1 111 1 1 1 , , , ,, , ,,,,,,..,.,,.,, .. .Two crit ical components of the Rb vapor magnetometer have active therm al contr ol circ uit s

(resista nce heater). The temper ature of the Rb gas cel l remain ed within a satisfactory range of+3 5 to +45 "C durin g al l operational periods while' the Rb l amp w a s satisfac torily maintainedbetween 115 and 120C.

Fo r purposes of comp arison, the predicted and actual (adjusted) tem perature data for th ebattery, p rime converter, and tran smit ter locations are shown in F igur es 9, 10, and 11 respec-tively. In general, the in-flight tem per atu res exceeded predict ions when the sun w a s shining frombelow the sp acecraf t equator (90 degrees to spin axis), while at angles above the equator t heactual temperatures w e r e equal to or le ss than predictions.

Power S y s t e m D a t aThe sol ar paddle output cur ren t and the spacecraft load current are shown as a function of

days after launch in Figu res 12 and 13. The average steady state spacecra ft load remained at37.0 w a t t s throughout the spac ecra ft lifetime. (The MIT experi ment causes a tran sien t of a fewmilliseconds duration to 50 w a t t s twice in ev ery 82 seconds, and a relativ ely constant ten-secondpower drai n to as high as 42 watts once in every 82 second s (neither tran sien t nor ten-secondload a r e telemetered). It is this in crea se that accounts for the fact that, following the fai lur e ofthe battery , t he sp ace craft would not ope rat e continuously, even though the so la r paddle outputexceeded the steady stat e space craf t power req uireme nt. Fo r continuous operation it is neces-s a ry fo r the s ol ar paddles to prod uce enough power to supply the additional MIT load above thesteady state requirement.)

DAYS AFTER LAUNCH0 9 18 30 42 55 70 78 I601 I 1 I (11 I 1 I

Y I PREDICTED RA N.I

.I

92 99 105 111 118 1I

\\\

I

I l l"'J131 138 145 I

I I '

I I I ADJUSTED FOR IN- IFLIGHT CALIBRATIONCHANGESI , I 1 I I l l 1 1 1130 140 150 140 130 120 110 100 90 80 70 60 50

SPIN AXIS - SUN ANGLE (degrees)Figure 9-1 MP -l I batte ry temperature.

11


16/33

1- 1.- l-- l-- l-- 100 90 80 70 60 50

DAY S AFTER LAUNCH55 70 78 85 92 99 105 111 118 125 131 138 145 152 159 166 17460

50-U-w -PI3-2nb-g 20 -8 +10E -

+-E ->

waa

-10

I

-e====

I

0 9I-

~

-40-

30-cs__

0--~

-130 1

I

..-----I

3dw -LLE- -c!5 +10d -z+

-10

I

--.-

I

20-

__

0----I

I


17/33

/ / I /AVERAGE SOLAR PADDLECURRENT (PP 9)K\ -r-

-v-- -SPACECRAFT CURRENT (F

f

-i-

4

-NOTE:-

I I ITATA HAVE NOT BEENOJUSTED FOR IN -F LIGH TCALIBRATION CHANGEI I I I L_____0 10 20 M 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 1 0

LAUNCH t l N OV 6 4 tl D E C 64 t l J A N 6 5 t l R B 6 5 t l M A R 6 5 t l A P R 6 54 OCT 64 DAYS AFTER LAUNCHFigure 12-IMP-I1 current dat a (not adjusted).

4 1 I S O h R P AD OGOUTPUT CURRENT( P P 9 )

5I - 2

SPACECRAFT CUR RENT( P P 4 )

0 10 20 30 40 50 60 i

h

I80 90 100 110 120 130

'E: FOR IN-FLIGHT CALIBRA-TION FHANGES , ,, , I , # ,140 150 160 170 180 190

LAUNCH t l N OV 6 4 t l D EC 6 4 t l J A N 6 5 t l R B 6 5 t l M A R 6 5 t l A P R 6 54 OCT 64 DAYS AFTER LAUNCHFigure 13-IMP-I I current data (adjusted).

The so la r paddles produced an aver age of 65.8 wat ts initially, a low of 43.5 wat ts s ix weeksafter launch, and 61.5 watts 3 1 /2 months afte r launch ( Figu res 14 and 15). Degradation of poweroutput amounted to about 1 6 percent afte r th ree months i n orbit. The variation of paddle outputas the satellite spins is shown in Figu re 13. Fo r example, at spin axis-sun ang les of 140 to 150degrees, the variatio n fro m lowest output to highest was 2 1/2 watts. At sun angles of about 100to 110 degree s, the variation during a spin revolution was over 16.5 watts. The tele mete red(Figur e 16) and adjusted (Fig ure 17) data of the regulated outputs of t he pri me and multi-converters indicates that these voltages remained within the specified tolerances of i l percent.

13


18/33

I 1 I I I I I l l 1 1NO RADIAT ION DAMAGE -33.6 W A l lS PER PADDLE SIDESP IN REVOLUTION

REVOLUTIONlN G A S P I

$-bII- 1 'MINIMUMi lI I0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180( d e g r e e s )

Figure 14-IMP-I I predicted power.

DAY S AFTER LAUNCH0 9 18 30 42 55 70 78 85 92 99 105 111 118 125 13 1 138 145 152 159 166 174 183 191

70i- J 1\\I

I

/

I

1\

I

I

1

PREO ICTED,(N O RADlATlOFDAMAGE)

///iI

TCTUAL POWERP2I I I &I030 140 150 140 130 120 110 100 90

SPIN AXIS - SU N ANGLE (degrees)Figure 15-IMP-I1 comparing overage with predicted power.

14


19/33

. ...

74-NOTE DAADCA H ISTEB R I

0 10 20 30 40 50LAUNCH tlNOV64 14 OC T 64

..

..

..

..

DEC 64

4

ii-i hFO . BEENI N - FLI G H TO N , C H A N G ES , 4

I I I - f

JA N 65 t l FEB 65 t 1 M A R 65 t l AP R 650 10 20 30 40 50 60 70 80 '

LAUNCH tlNOV64 t l D E C 6 4 '4 OC T 64 DAYS AFTER LAUNCHFigure 16-IMP-I1 voltage data (not adjusted).

. .

..

..

..

..

..5 .

I .

0 1JA N 65

DAYS AFTER LAUNCH

..

..

.i

. *- 4TADJ L

. . .I .

= I..AVE BEE1EO FOR IC A LI B R A TI O N C H A N G ES

1 130 140 150 160 170 180 190. FEB 65 t 1M A R 65 t l AP R 6

Figure 17-IMP-I1 voltage data (adjusted).

15


20/33

l1111111111111111I II I 1 I I I1II I1 IIIII I I

BATTERY PROBLEMThe battery in IMP-I1 failed as a resu lt of the exce ssive te mper atur e environment to which

it was subjected. Ther e were two fac tor s identified as causes of this unsuitable battery tempera -ture (+55"C at 55 days afte r launch).

1. The tip-off or perturbation of the spin axis incu rred durin g the launch phase caused thespin axis-sun angle to pro gr es s to about 147 degrees , or about 12 deg ree s beyond thenominal limit. This region is the warmest fo r the battery.

2. Although sun ang les over 135 de gr ee s were beyond the nominal limit fo r the launchtrajector y and time, the thermal control design limit for IMP was set at 150 degr ees. Thether mal control failed to maintain the in-flight temp erat ure of the battery within designlimits at angles over 130 degr ees .

It is an established fact that sil ver cadmium batter ies of the type used on IMP exhibit adra sti c reduction of lifetim e when subjected to temp erat ures in exc ess of +35"C.* Te st s haveshown that, compared to lifet imes at +25"C, sil ver cadmium c ell s last only 70 percent as longat +35"C and only 20 percent as long at +50"C. The design of the cel ls employs a multi-layercellophane membrane as a sep ara tor between the silv er and cadmium electrodes . During the lifeof a cell, the sil ver rea ct s with the cellophane, laye r by laye r. This reaction is fairly slow atroom conditions but is accelerated at higher tem pera ture s. When the sepa rat or of a cell fails,a short circuit results, thereby impressing a higher than no rmal c harge voltage on the rema iningcel ls of the batte ry. Gas evolution begins to caus e increasing int erna l pr es su re within the goodcells, ultimately resulting in a cell case ruptu re and electrolyte leakage. Even at th is point, abatt ery might be able to op erat e partially depending upon the a mper age demands of the load.However, when all of the electrol yte outgass es from the leaky cell, an open circ uit exi sts and thebattery is there aft er incapable of supplying any cu rre nt.

In the cas e of IMP-11, batt ery performanc e appeared to be satisfa ctory until the spac ecra ftentered a perigee shadow (Appendix D) on 30 November. The spa cecra ft immediately turned off.However, on the preceding orbit, the batter y operat ed the spac ecra ft through a shadow period of20 minutes duration. It is concluded, i n the failure mode hypothesis, that a fail ure of a cellsep ara tor occu rred between 1200 UT, 20 November and 2200 UT, 30 November 1964-approximately1400 hou rs after launch.

At thi s time, the output of the sol ar paddles was mar ginal due to the incident sun angle, andas the sa te lli te spun, the output periodically fe ll below the needs of the space craf t. Because thedeficiency w a s small, perhaps 100 to 200 milliamp eres, the twelve good ce lls we re able to supplyth is need. However, as the spacecraf t entered the ea rth's shadow, the enti re spa cecraft load(2.8 amp eres ) was tra nsf err ed rapidly to the battery. With only twelve good cells it se ems likely

*Private communication with T. Hennigan and K. 0 . Sizemore, GSFC, December 1964.?Private communication, K . 0 . Sizemore, GSFC, July 1965.

16


21/33

tha t the batt ery voltage dropped below the 12.0 volt thresh old of under-voltage turnoff and causedthe spacec raft power to shut down for eight hours.

Meanwhile, t he twelve good cel ls were subjec ted to the 19.6 volt charg ing voltage. If allcells wer e exactly balanced, each would have 1.63 volts im pres sed ac ro ss its terminals. Sinceexact equality among all cells is not a characte ristic of a typical silver cadmium battery,especially afte r two months in orbit, it is reasonable to ass ume that som e cell s would have le ssand so me more than 1.63 volts acr oss th eir t erminals . Gas evolution begins at 1.64 volts percell and it therefore is suspected that some cells we re producing internal g as pr ess ure build-upsand leakage of electro lyte at this time.

On 3 December, the spacecraft entered a sh ort (le ss than two to thr ee minutes) shadow of themoon which w a s pre ceded and followed by about 30 minutes of penumbra.* The spa cecraft con-tinued to operate through this period. The tr av er sa l of the penumbra caused the gradual dec rea seof so la r output power and the gradual tr an sf er of the load to the battery. Under these conditionsand despite the shorted cell, the battery was able to supply the power demand without having theprimary system voltage drop below the turnoff point (12 volts). The sp acecra ft continued to turnoff each time it entered the earth's shadow, once each orbit.

On 5 Dec ember 1964 at about 1400 UT, the sp acec ra ft turned off while in sunlight. This,according to the hypothesis, ma rk s the complete failu re of the battery, that is, an open circuitcaused by the absenc e of electro lyte in a cell.

Therea fter, the batte ry was totally incapable of supplying any current whatsoever. Thespacec raft could and did oper ate at tim es when the sol ar paddles wer e able to supply all of thepower needed. If the sun angle w a s such that the paddle output would periodically dip below therequire ment of the spacecr aft, as the satellite spun turnoff would occur immediately.

One furt her piece of data furth er substa ntiate s this fa ilur e hypothesis. Since the recycletim ers receive power from a regulator whose input is the solar paddle and/or bat tery voltage,the ti me rs would NOT operate , after a turnoff, fo r any pe rio ds spen t in the shadow of the ea rth,unless the battery w a s capable of supplying cu rren t. In other words, if the batt ery had failed andthe satellite w a s in darkness, the tim er s would recei ve no elec tri ca l power. Thi s being the case,one would expect that the recy cle ti mes would be extended when a turnoff occurred due to a shadowcompared to a no-shadow case . On orbi ts 126 through 131 occurri ng fro m 5 April through 1 2April 1965, apogee shadows of from 2 1/2 to 4 1/2 hours were tra vers ed by the satellite. Thelo ss of signal peri ods for t hese o rbi ts averaged about 12 hour s in duration, instead of t he pre-viously dependable 7 1 /2 + 1/4 h ours. Thi s confirms the supposition that the batter y was notcapable of supplying any cur ren t whatsoeve r.

.~*Region of partial i l l u m i n a t i o n .

17


22/33

CONCLUDING REMARKSThe IMP-II spacecr aft, the second in the continuing s e r ie s of IM P satelli tes, was not injected

into an acceptable orbi t and hence could not accomplish the pri ma ry mission objectives of study-ing the interplaneta ry medium.

The lowered apogee of only 51,600 n.m. or about one-half of the des ir ed altitude was attri-buted to a malfunction of t he third s tage solid propellant m otor of th e Delta 26 launch vehicle.Therefore the IMP-I1 launch w a s subsequently categorized as a mission failure.

The spac ecraft operated satisfactorily for nearly five of its first six months in space. Thenine scientific experim ents op erated properly and most of the se condary objectives wer e attainedas w e l l as the accumulation of signif icant dat a within the magne tosphe re.

Operation of the sp ace cra ft aft er two months in orbit was m ar re d by the failure of the si lve rcadmium battery which was a direct result of excessive temperature caused by the attitudepert urba tion introduced by the launch malfunction and the inability of the pass ive therm al co ntro lto maintain the battery within its design limi ts. The ther mal design and battery charging tech-niques wer e modified fo r follow-on IMPS to prec lude the prob lem s encountered during the IMP-I1flight.

(Manuscript re ceiv ed October 1, 1965)

REFERENCES1. Ca rr, Fran k A., "Flight Report, Inte rplaneta ry Monitoring Platfor m IMP-I - Explorer XVIII, If

NASA Technica l Note D-3352, 1966.2. "Initial Results from the First Interpla netary Monitoring Pla tform (IMP- l ) , ' IGY Bulletin

No. 84, National Academy of Sciences, June 1964.3. Projec t Development Plan, P ro ject IMP, Revision 2, GSFC, June 1963.4. Flight Report fo r Vehicle S/N 392/20111/20103 Delta Pr og ra m - Mission N o. 26, Douglas

Aircraf t Co., Lo s Angeles, Calif., Report SM-44986, December 1964.5. Delta Vehicle Flight Fai lur e Report, Launch 26, GSFC Document X-623-65-128, March 1965.

18


23/33

l t en

1.2.3.4.5.6.7.8.9.10 .11.12 .13 .14 .15.16 .17 .18 .19.20.21.22.23.24.25.26.27 .28.29.30.31 .32 .33 .34 .35 .36 .37 .38 .

39.40.41.42.43.44.45.46.47.48.49.50.51.52.

3 j 73/233/243/243/243/254/54/5

From

12391435010509322002005201231403

Date10/4/6811/2511/1112/112/212/412/512/512/612/612/612/712/712/712/712/812/812/812/912/912/1012/1012/1012/1112/1112/1212/1212/12

12/9

12/1412/1512/172/5/6512/182/92/92/102/10

3/33/33/43 /43/43/53/73/73/243/243/243/243/25v 5

Timf0345004311440606164703271359*21510612140721470551061321230526131420520518141322120532'1343234909541814023010551929060916500510141417181625234607061426

?

132320490530*1315*2320*0710*1025*2000*0055*0925*1955*2115*02001359

Spacecraft CTo

Date Time

1i j3012/212/312/512/512/512/612/612/6121712/712/712/712/812/812/812/912/912/912/1012/1012/1112/1112/1112/1212/1212/1312/1512/163/4/6512/181/92/93/92/102/10

11/10/64 1720 A 511/25 04182248 40930 2 82011 1706421434*225106421414220905530614220506001328215506481435 *72 2 2 00634*16330125 *41027190603271154 A 52246 S08522 03 5 4 5060317490908162923 5007101430

?

Appendix AI M P 4 Spacecraft Operat ional Periods

DurationMill.

35 +155504 +s24 i2824 *71 53500300722020142341403302 2 A 7080 2 1503333525759 +1517 +24145 *3557355004040404

(Tracking Efforts Reduced Because ofIntermittent Operation)3/3 13333/3 122063/4 105563 4 15253/4 I23503 /7 0257

1017261030471435100807372304

;pacecraft OffDuration

lours777777777770??777777777877777788237777

I : : 7I 1781011124

I 10

Min.25 5152618 +617 12816 +717*17*2125334220 ?

211424232537 *1712*12*162917242835 +1523 *95835l l ?2917171616

1624*19*5520*28*2120 ?20 ?23 ?13?08 ?3653

RemarksSpacecraft Off Perio ds Represen t Undervoltages(-7 1/4 hr s) and/or Oth er Loss of Signal CausesAll Dates and Times are Universal Time (UT)The spacec raft was activated 40 minutes priorto launch

Turnoff at 2/4, 1749 wa s not undervoltage but ratheI command-off o f the spacecraf t ca r r ier f rom un-mown sou rce. Car rie r commanded on at 2/5, 1718End of sp ace cr aft "Lifetime No. 1"Xegligible amounts of d ata were transm itted from1/10 - 3/2/65Start of spacecr aft "Lifetime N o. 2"

rurnoff at 1434:58 during sequence 2, frame 14,ihannel 9.

Extended re cyc le time due to clock stoppage whilein shadow.~~

*Est imatedSources: S T A D A N dai ly report s and s pacecraf t data .

19


24/33

0249101123100730150322381019182209172118045812151937153622580620183109181640

15/654/64/64/74/74/74/74/84/84/94/94/104/104/104 /114/114/124/124/134/13

IMP-11 Spacecraft Operational Periods (Continued)Spacecraft On

ToSpacecraft Of

DurationRemarks

Spacecraft Off Per iods Re present Undervoltages(7 1/ 4 hrs ) and/or Other Loss of Signal CausesAl l Dates and Times ar e Universal Time (UT)LOS period ending at 1856 was an undervoltage.Same as item #51LOS period ending 2310 wa s a n undervoltage.

[temDuration

Time19320256104200080747151922461105183209192137045912201943154123030625183909241645

Min.36073 158171608461002190 10506050 505080605

Min.1715382216192317455921161753 ?1717D6 ?3916

?201717161717171716171530

rime 11 8 5 6 I

-ate Date Hours7712717711714

11777197712147

777777777777

4/5/654/ 64/64/64/74/74/744/84/94/94/104/104/104/114/114/124/124/134/13

7 /117/157/157/157/157/167/167/167/177/177/177/187/187/18

53.54 .55 .56.57 .58.59 .60 .61.62.63.64 .65.6 6 .67 .68 .69 .70 .71 .72 .

73 .74 .75 .76 .77 .78 .79 .80 .81 .82 .83 .84 .85.86.

Same as i tem # 5 114:45 off represents tw o recycle periods.Same as i tem #51LOS period ending at 2118 was an undervoltage.

14:39 off represents two recycle periods.End of sp ace cra ft Lifetime No. 2.Less than 10 minutes of data rec orded p er dayf r o m 4/14 to 7/10/65(Tracking Effo rts Reduced Because ofIntermittent Operation)

?0108083115522325065914352208*0546*13142100045212131950-

7 /117/157/157/157/157/167/167/167/177/177/177/187/187/18

?0111083516082343071814512224*0557*13442135045812202004

1203041618191616163035060714 NOTE: An estimated 420 undervoltage recyclesoccurred as of 1 August 1965.

. ~. .. ~--*EstimatedSources: STADAN daily reports and spac ecraft data.

20


25/33

Day123456789

10111 2131 41516171819202 122232425262728293 03 1

IMP-I1 Spacecraft Operational P eri ods (Continued)IMP-11 Minutes of Data Acquired, 1965July-

--70-----80--

3739

10924260

7053280

198380

664831 2

September6

10880

157

3 4432787

198238169115285

187

216115122100

58338338

8781213-

October

NOTE: A dash means no attempt to acquire data was made.Al l data acquisition efforts ce ased as of 1November 1965.

21


26/33

I11111111111111111111111111 I1 II


27/33

Appendix B

Spl"rpm)Rate

14.5814.5114.2914. 2514.2714.3214.4514.5514.7314.80-15. 1315. 2515.3515.515.7516. 016. 518. 616. 717.017. 1I7 2517.3517. 517.717.917. 9I 8 0

~

18.017.9517.917. 817.7217. 6417.517.3817. 28

Date

10/4/6410/410/610/810/1010/1210/1710/2010/2510/2711/111/5l l / 811/1111/1511/2211/3012/1312/1612/1912/2712/301/3/651/6/651/11/651 17/651124.651, 28,'652/ 1/652/4/652/ 7/ 653/5/ 653/103/143/ 183/223/211/21/4

(volts:15.819.619 .619.719.719.719. 819. 819.919.819.819.914.919. 919.9520. 020. 019. 819. 819. 819.819.19.8519.819. 919. 919.9520. 020 019 820. I20. 120. 020. 120. 1-20. 120.120. 1

Days AfterLaunchr + 24 minr + 8 1/2 hr s

2 1/24 1/26 1/28 1/2

13 1/216 1,221 1 223 1/228 1/232 1/235 1/238 1/242 1/249 1/257 1/270737684879194990512162023 li 2265257616589748082

PP4(amps)2. 271. 881.871. 901.901. 911. 931. 951. 961. 961. 971. 982.471.982.002. 002. 001.981.981.971.991 971 991.991.991.981.981. 981. 961. 971.971. 961. 951. 971. 97- -I , 971. 981.98

S""Angle125-130130131133134135137139142143144145148147147148144140138136131129126124120115109108104101998076747168858260

(amps3.093. 093.022. 982. 982. 902. 722. 672. 552. 492. 372. 322.372. 202. 202. 202. 322.432.492. 552. 812. 672.872 722 782. 762.782. 782. 652. 672. 322. 552. 612. 812. 6 1

2. 492.432. 37

I M P 4 P e rf or m an ce P a r am e te r D a t aTe lemetered or 0bserved Va lues (Uncorrec ted ](From Qu ick Look Tap es)

PP 5( C)23. 63741.54244.345.84849.8515152.55353.253 . 95454.755.454.75453. 751. 350. 749.74844.340. 33429. 72520.919. 110.510.510.410.4

11. I12. 112.1

PP 8('C)38. 337.2383838.738.440414141414138.241.441.541.441.943.043.343.343. 944. 044.444.444.844. 84545. 145.34545.445 445.445. 245. 3- -45.045. 045.0

PP2(volts50. 050. 250.450. 550. 550. 550. 650. 850. 951. I51. 351.351. 351. 351. 351. 351. 351. 351.351. 251.351.2551. 351. 351.2551. 351. 351. 351. 351. 351.351. 351. 351. 351. 3-51. 351. 351. 3

(amps)3.423.423. 333. 203. 153. 052. 852. 792. 632. 582.492.402.452. 352.342. 352 362.552.832.712.922.993. 083. 08

~

3. 253. 203. 133. 092.982.882.822.912. 922. 94- -2.952. 902.81

PP 8(volts)12.212.212.212. 212.212. 212. 312. 312. 312.312. 312. 312. 312.312.312.412.512.312.312.312. 312. 312. 312.312.312.312.312 312.312. 2512.312. 312. 312. 312. 3-12.312. 312.3

(amps:3. 783.783. 653. 523.403. 333. 022. 902. 782. 672. 612.552. 612. 492.432.432.492. 722.842.903 213 273. 403. 523. 653. 653. 653. 653. 653.463.463.093.213. 213. 27

3. 403. 403.40

PPI2(volts)7. 07. 17. 17. 17. 17. 17. I7. 157. 27. 27. 27. 27. 27. 27.27. 27.31. 17. 27. 17. 27. 27. 27. 27.27 27. 27. 27. 27. 11. 21. 11. 27. 17. 1-1. 27. 27. 2

PP 3(ma)600

3310-10

91010101161I517

Iariabl3322

:oo- 10125151616202022222325242525222619212020-202020

PP 7( 'C)29.435.439.54041. 643.74546. 4484849.449. 55151. 35252. 853 .852. 251.851. 019.447. 84745.212. 238.532. 42924. 620. 218.8I1 812. 111. 811. 8-

12.813. 614.4

PPI0("C)

~

-8+ I+I0.40+I 2-2-2-4-4- 6- 6- 8-7-7-6-40+l/2+2799. 41113.61516. 516.315. 913. 6139. 31213. 313-10. 69. 29. 2

PPI3('C)

~

108117118118118118. I119. 5119.5119118. 118. c118.4118.4118. 1116. 5I19119.7120120.5120. B121.6121.8122122122122122122122121.8122121120.7120120-119. 7119119

-PPI4('C)

~

29. 324. 5272727. 830.230. 330.431313232-33. 133. 233. 234. 8353535. 535. 935. 536353433. 130. 630.429. 127. 62834. 13636. 538. 6-10. 111.4$1.5~

-PPI!( 'c :-

29.4424646. 548. 951. 352. 553. 6555558. 558.457.859. 559. 659. 761. 459. 859.659.4-

54.85351. 64643. 737.433.329. 324. 72418. 719. 319.519.9-20. 220.320.5-

00-1/2-1/2-1-1-1.85-2. 3-2. 7-3-3. 0-3. 2-3. 5- 3-4.3-4.9-4.9-2. I-2.4-2. 6-3.2-3.2-3.4-3. 3-4-3. 2-3. 4-3 3-3. 5-3-3.5-3.0-3 .0-3.0-3.0-- 3 . 0- 3 . 0- 3 . 0

*Intermittent 17.6.**Cone F ilt er Number (CFN).

23


28/33

1111111111ll IIIII I I1


29/33

Appendix C

PP8(volts)

12. 012. 012. 0

Days >Launch P P I 2(volts)

7. 07 . 07 . 0

I' + 24 M i n8 1/2 h r2 1/24 1/26 1/ 28 1/2

13 1/216 1/ 221 1 /223 1/228 1/232 1/235 1/ 238 1/242 1/249 1/257 1/27073768487919499

10 511 211612 0123 1/212 615215716 116 516 917 418 018 2

P P 6( "C)

36 .33 7 . 238- -

3 8 . 3~~

3 9 . 2

4 0 . 2- -4 0 . 2

- ---

40.341.6

-- --.

42.9

-43.4

43 .843 .8- -----

43 .4

IM P - I I P e r fo rm a n c e P a ra m e t e r Da t aCorrected for Analog Oscil lator [ A O ) Cal ib ra t ion Dr i f t

P P 7 P P l O P P 1 3("C) ("C) ("0

29.4 -10. 1 106.835.4 - 1. 2 -39.5 - 1 . 2 11 7

- 1 . 8 -41.2 - 1 . 4 -- - 1 . 7 -

43. 6 - 6 11 8~~~

- - -- 8. 4 -

4 7 . 8 - -- - - -- _ - -

-11 -48.7 - -- - -

50.4 - 8 .4 117 .548. 9 - 4 .4 117 .9- - - -

- - 2 . 3 ~+ 2 . 5 -- - -

44.2 - 1206.6 -- -

- 1 0 . 5 -30.4 12. 0 .-_ - _ -- _ _ -~ _ _17 .0 8 .6 12010.0 4 . 8 1 1 9 . 1

7. 6 118. 6IO . 0 8. 9 117. 910. 0 8. 6 117. 9- _ _ -11.0 5.8 117. 511.8 4. 7 116. 812.7 4. 7 116. 8

I

~

27. 9 28. 423. 1 39.8- 44. 8- -26. 4 47. 6- 49. 9- -

27. 6 50 .7~~

- -- 53.2

29 .2 ~- -- -

30. 4 56.- -32. 0 57. 932. 2 56. 2- -

32. 7 56. 03 3 . 1 ~

-- 51. 633.2- 48.9

31. 2 46. 4- 4 1 . 5

27. 9 35. 3-~- 27.4~~

25. 2 22. 231. 3 16. 933. 2 17. 5- 17. I35 .7 18 .1- -37 .4 18 .438 .7 18 .538 .8 18 .7

1 P P 2(volts)1.881. 871. 881 . 8 81 . 8 81. 881. 891. 891. 891. 891. 882. 381. 881. 881. 881. 881. 881. 881 . 8 81. 881. 881.881. 88

1 . 8 81. 881.881. 881.88I. 881.88I. 881 . 8 81.88

1.88

1 .881.881.881.88

50. 250. 450. 2

23. 63.02 3.35 3. 65 372. 96 3. 27 3. 52 41. 52. 90 3. 16 3.40 41. 12. 90 3. 09 3. 27 43. 62 .84 2 .99 3 .2 1 45 .22. 64 2. 76 2. 90 47. 22. 55 2. 67 2. 78 48 .42. 43 2. 51 2. 67 49 . 72. 37 2. 46 2. 55 49. 72. 26 2. 37 2.4 9 51. 12. 20 2. 29 2. 43 50. 22. 26 2. 35 2. 49 50. 42. 09 2. 23 2. 37 51. 12. 09 2. 22 2. 32 51. 22.0 9 2. 23 2 .32 -2. 20 2. 24 2. 37 52. 52. 32 2. 43 2. 61 51. 72. 37 2. 51 2 .72 -2.43 2. 60 2.78 -2 .49 2 .80 3 . 09 48.52. 55 2 .87 3 /15 -2. 55 2 . 9 3 3. 27 -2. 61 2 .95 3 .40 45. 3

2. 67 3. 132. 67 3. 082. 67 3. 002. 55 2. 962.55 2.842. 20 2. 762. 43 2. 702.4 9 2. 792.49 2.802.49 2. 82

2. 67 -

- -2. 37 2. 832.32 2. 782. 26 2.7 5_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~

50.2150. 2---

50. 250. 350. 649. 949. 949. 949. 949. 94 9 . 94 9 . 949 .94 9 . 949. 949. 949. 949.949. 949. 949. 949. 949. 949.949 .949.949. 949 .949. 949 .949. 949 .949. 9

12. 0 7. 012. 0 7. 012. 1 6. 9512. 0 6. 9512. 0 7. 012. 0 7. 012.0 7. 012. 0 7. 012. 0 7 . 012. 0 7 . 012 .0 7 . 012. 1 7.012. 2 7. 112. 0 6. 912 .0 7 . 012. 0 6. 912 .0 7. 012. 0 7. 012. 0 7.12. 0 7. 012.0 7. 012 .0 7.12.0 7. 012. 0 7. 012.0 7. 012. 0 6.12 .0 7 .012. 0 6. 912 .0 7 .012. 0 6. 912 . 0 6. 912 .0 -12.0 7 . 01 2 . 0 7 . 012.0 7 . 0

PI(m

12 20000000005

2210

16555

1010101011121212121013

88888888

~

*PPI - 7, Analog Osci l lator 1, PP8 - 1 5 , Analog Osc i l l a tor 2 , Comb Filter Number (CFN).

25


30/33


31/33

PassLAUNCH

1*23456789

1 0111 2131 4151 617181920212223242526272829

Appendix DIMP-II Shadow Times

Date10/4/65

10/510/710/810/91 /1110/1210/141 /1510/1710/1810/2010/2110/2210/2410/2510/2710/2810/3010/3111/211/311/411/611/711/911/1011/1211/1311/15

II Durationmin)Star t Time(UT)0345142501 06114722280908194806281709034914300110115122320912195206321712035314330114115522350916195606361716035614360117

20.32222222222222323232323232323232323232323232323232323232323

* End of orbit 1, etc .

27


32/33

I I I111111IIIII I II I1 ll11l1l1lllI I II

IMP-11 Shadow Times (Continued)~~

Pass

303132333435363738394041-4243444546474849505152

53-12512 612 712 8129130131132

Date

11/1611/1711/1911/2011/2211/2311/2511/2611/2811/2911/3012/2

12/3 (Moon Shadow)12/312/512/612/812/912/1112/1212/1312/1512/1612/18

12/19/64 - 4/4/654/5/654/64/74/94/104/124/13

* Inc ludes only about 2 or 3 m inutes of total darkness .tTotal da rkness , ex c lus iv e of penumbra.

Star t Time(UT)

11582239091919590639171903591439012012002241092216331954063417140403144301231204224509262 0070648-014212032250095421130851-

Duration(min)

23232322222221212121202068*1 91918171 7161 51 4121 0

80

2 hrs 38 min t3 h r s 56 min t4 h r s 2 3 m in t4 h r s 2 0 m in t3 h r s 5 0 m i n t2 h r s 4 5 m in t

0

28 NASA-Langley, 1966 G-703


33/33

T he aeronautical and space activities of the Un ited States shall beconducted so as t o coiitribuie . . . o the expansion of human knowl-edge of phenomena in the atmosphere and space. Th e Administr.ationshall provide for the widest practicable and appropriate disseminationof info rmatio n concerning its activities and the results thereof .

-NATIONALERONAUTICSND SPACE CTOF 1958

NA SA SCIENTIFIC A N D TECHNICAL PUBLICATIONSTECHNICAL REPORTS:important, complete, and a lasting contribution to existing knowledge.TECHNICAL NOTES:of importance as a contribution to existing knowledge.TECHNICAL MEMORANDUMS: Information receiving limited distri-bution because of prelim inary data, security classification, or other reasons.CONTR ACTOR REPORTS: Technical information generated in con-nection with a NASA contract or gra nt and released under NASA auspices.TECHNICAL TRANSLATIONS: Information published in a foreignlanguage considered to merit NASA distribution in English.TECHNICAL REPRIN TS: Information derived from NASA activitiesand initially published in th e form of journal articles.SPECIAL PUBLICATIONS: Information derived from or of value toNASA activities but not necessarily repor ting the results -of individualNASA-pro grammed scientific efforts. Public ations include confere nceproceedings, monographs, data compilations, handbooks, sourcebooks,and special bibliographies.

Scientific and technical information considered

Information less broad in scope but nevertheless

Detai ls on the avai lab i l i ty of these publications may be obtained from:

SCIENTIFIC AND TECHNICAL INFORMATION DIVISIONNATIONAL AERONAUTICS AND SPACE ADMINISTRATION

Washington, D.C. PO546

flight report - interplanetary monitoring platform imp-ii (explorer xxi)

Documents