- -7
5, 41, AN MA 969-DECEMBER43 D 47 197 AY' 1969-DEEBER 1972 S(NASA-TM-X-70481) TRAJECTORIES OF N73-33809 EXPLORERS 33, 35, 41, 43 AND 47, MAY 1969 - DEC. 1972 (NASA) 72 p HC $5.75 CSCL 22C Unclas
"f -" G3/30 19441 D.' -'.FAIRFIELD K. W. BEAANNON( R. P LEPPING N. F. NESS
"NFORMATN SERVI-E
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S-ENBET MA RYLAND
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14 N- TRAJECTORIES OF EXPLORERS 33, 35, 41, 43 and 47
May 1969-Dec 1972
D.H. Fairfield K.W. Behannon R.P. Lepping N.F. Ness Laboratory for Extraterrestrial Physics Goddard Space Flight Center Greenbelt, Maryland
October 1973
/0 This document represents a continuation of a previous document (Behannon et al. 1970) and is presented with the intention that it will stimulate and facilitate correlative studies of data from various spacecraft. Figures 1-54 consist primarily of solar ecliptic plane projections of orbits of five different satellites although a limited number of XZ projections are shown to illustrate the large excursions of Explorer 33 away from the ecliptic plane.
Nominal positions of the magnetopause and bow shock are included for reference.
The plots are intended only to represent the trajectory of the spacecraft and imply nothing about the operational status of the various experiments nor the availability of the data. Information on these latter points can be ob- tained from the National Space Science Data Center, (e.g.
King, 1971). It should be pointed out, however, that
Explorers33 and 35 were very long lived spacecraft (> 2 yrs) and numerous experiments either ceased operation or exhibited a gradual deterioration during the extended lifetime.
On all plots the points indicating the locations of
Explorers 33, 35 and 47 represent the spacecraft position
1 at the beginning of the day. For Explorers 41 and 43 the
points represent the location and day of apogee. Specific
comments on the various spacecraft are as follows.
Explorer 33 (alternate name AIMP-D) Launched July 1, 1966
The Explorer 33 GSFC magnetometer ceased operation
after 119 weeks which is an interval ending before the period covered by this document. For completeness the trajectory is included through Feb 1970 when the trajectory was readily available to the authors.
Explorer 35 (alternate name AIMP-E) Launched July 19, 1967
The GSFC magnetic Field Experiment on Explorer 35 has been described in detail in a separate publication (Scearce et al., 1969) and more briefly by Ness et al. (1967). The spacecraft is in a lunar orbit (aposelene approximately 9400 km, periselene 2500 km) and consequently on the scale of the magnetosphere its orbit can be approximated by the orbit of the moon. The experiment has provided an extensive body of interplanetary, distant magnetosphere and lunar environment data and was still operating when data collection from the spacecraft was discontinued in June 1973.
2 The flipper on the Explorer 35 magnetometer failed on
May 20, 1969 (week 96, day 139). The result of this failure
was an inability to calibrate the zero level of the spin
axis (Z) sensor. To process the data subsequent to week 96,
the average zero level for weeks 1-95 was used for the Z
sensor. It was concluded from the statistics of the calibra-
tion data in the X,Y and Z axes from the first 95 weeks that
this long term average would be as accurate an estimate as
that obtained by any other means. This estimate is con-
sidered conservatively to be accurate to within +0.5Y when
used to calibrate data beyond week 95, if it can be validly
assumed that the statistical characteristics of the Z sensor
zero offset remained similar to those of weeks 1-95 through-
out the useful instrument lifetime. The overall history
of the X and Y sensor zero levels during almost five years
supports this assumption.
Experimenters were warned by the project to be suspicious
of their data beginning about May 31, 1971 (week 150) because
of the onset of spacecraft performance problems. Magneto- meter data subsequent to that date was still of good quality, but data availability became progressively more intermittent
3 with time and some:increase in the scatter of detailed data points can be seen. The usefulness of the magnetic field data is questionable beyond week 248 (April 1972) due to the frequent gaps in the data and increasing difficulty in obtaining reliable calibration data. By May 1973 little processable data was being received from the spacecraft.
Magnetic field data tapes cover one week intervals and are numbered beginning with spacecraft launch. Table 1 lists the correspondence between week number, date and decimal day (decimal day is the day of the year, where Jan 1 is denoted
day zero) to aid the reader in requesting data.
Explorer 41 (alternate names IMP-G, IMP-5) launched June 21, 1969
The GSFC magnetometer experiment on Explorer 41 was very similar to the experiment on Explorer 34 (IMP-4) (Mish,
1972). The Explorer 41 experiment provided high quality magnetic field data for 381 orbits until the spacecraft reentered the atmosphere on Dec 23, 1972. Data coverage was continuous except for orbits 262-269 when no tracking was provided and orbits 270-284 when coverage was restricted
to intervals when the spacecraft was expected to be near the
4 plasma sheet. The experiment has been described by Fairfield and Ness (1972).
Figure 55 presents the XZ projectionsof four orbits spaced one year apart with apogee in the sunward direction in the noon meridian plane. Comparison of these orbits indicates the gradual changes that took place in the orbit in an inertial coordinate system. It should be pointed out that launch near the summer solstice with apogee in the sunward direction dictated that inbound orbits of Explorer
41 were at high geomagnetic latitude and provided good coverage of the polar cusp in the outer magnetosphere.
Explorer 43 (alternate names IMP-I [eye], IMP-6) launched March 13, 1971
The GSFC magnetometer experiment on Explorer 43 (Seek et al.,1973; Fairfield, 1973) continues to provide high quality magnetic field data at the time of this writing
(Aug 1973) after more than two years operation. Data coverage has been continuous throughout this interval.
Figure 56 presents the XZ projectionsof two noon meridian plane orbits to illustrate the gradual changes taking place in an inertial coordinate system.
5 Explorer 47 (alternate names IMP-H, IMP-7) launched September 22, 1972
The GSFC magnetometer experiment on-board Explorer 47
(Scearce et al., 1973), which was turned on at 1411 UT on
September 26, is one of 13 particle and field experiments on the s/c. Explorer 47 is the first part of a two s/c sub- series (IMP's H and J) planned so that at least one of the two s/c would be in.interplanetary space at any given time to monitor the solar wind in the earth's vicinity and so that unique intercorrelative studies may be pursued. The
H and J orbits are planned to be identical, aside from an
1800 phase difference of s/c position in longitude. IMP-J is scheduled for launch 25 October 1973.
The overall experiment differs from the previous magnetic field experiments in the IMP series in two major ways: (1) its increased sampling rate of 25 samples/sec and (2) the manner in which the data is compacted on-board the s/c through a technique of delta-modulation, enabling the higher sampling rate at a moderate telemetry bit-rate
(180 BPS).
6 The experiment on-board Explorer 47 has experienced two serious misfortunes. On Dec. 28, 1972 the sensor flipper, useful for determining the spin axis zero level offset, ceased functioning. Then on April 4, 1973 a mal- function in the power supply rendered the experiment totally inoperative. Also the quality of the data, due to s/c antenna pattern problems, is partially degraded, especially during the first two months. Nevertheless, the experiment yielded over 6 months data, most of which are of good quality.
Degradation of the data due to the flipper failure is less serious, because of reliable zero level determination based on statistical methods.
The orbit for Explorer 47 is nearly circular with a radius of 35 + 2-1/2 RE; the first full orbit eccentricity was
0.0756. The inclination of the orbital plane with respect to the ecliptic plane was 32.60 on September 25, 1972 and
31.10 one year later.
In figures 51-54 inclusive the ecliptic plane projection of the orbit is shown as a dashed curve. Notice that dots are used to designate the first 13 days of any month, crosses for days 14 to 25 inclusive, and open circles for days 26
7 to the end of the month. Only odd days are labeled, except for December. During the highly elliptical initial trans- fer orbit shown in figure 51, no experiment had yet been turned on. For January through April 6, 1973 (after experiment failure) the s/c, of course, follows a similar near circular orbit with the azimuths shown in table 2.
8 TABLE 1 EXPLORER 35 CALENDAR
Week Begin Date Decimal Day Week Begin Date Decimal Day
94 1969 May 1 120 125 Dec 4 337 95 8 127 126 11 344 96 15 134 127 18 351 97 22 141 128 25 358 98 29 148
99 June 5 155 129 1970 Jan 1 0 100 12 162 130 8 7 101 19 169 131 15 14 102 26 176 132 22 21 133 29 28 103 July 3 183 104 10 190 134 Feb 5 35 105 17 197 135 12 42 106 25 204 136 19 49 107 31 211 137 26 56
108 Aug 7 218 138 Mar 5 63 109 14 225 139 12 70 110 21 232 140 19 77 111 28 239 141 26 84
112 Sept 4 246 142 Apr 2 91 113 11 253 143 9 98 114 18 260 144 16 105 115 25 267 145 23 112 146 30 119 116 Oct 2 274 117 9 281 147 May 7 126 118 16 288 148 14 133 119 23 295 149 21 140 120 30 302 150 28 147
121 Nov 6 309 151 Jun 4 154 122 13 316 152 11 161 123 20 323 153 18 168 124 27 330 154 25 175
9 Week Begin Date Decimal Day Week Begin Date Decimal Day 155 1970 July 2 182 186 Feb 4 34 156 9 189 187 11 41 157 16 196 188 18 48 158 23 203 189 25 55 159 30 210 190 Mar 4 62 160 Aug 6 217 191 11 69 161 13 224 192 18 76 162 20 231 193 25 83 163 27 238 194 Apr 1 90 164 Sept 3 245 195 8 97 165 10 252 196 15 104 166 17 259 197 22 111 167 24 266 198 29 118
168 Oct 1 273 199 May 6 125 169 8 280 200 13 132 170 15 287 201 20 139 171 22 294 202 27 146 172 29 301 203 June 3 153 173 Nov 5 308 204 10 160 174 12 315 205 17 167 175 19 322 206 24 174 176 26 329 207 July 1 181 177 Dec 3 336 208 8 188 178 10 343 209 15 195 179 17 350 210 22 202 180 24 357 211 29 209 181 31 364 212 Aug 5 216 182 1971 Jan 7 6 213 12 223 183 14 13 214 19 230 184 21 20 215 26 237 185 28 27
10 Week Begin Date Decimal Day Week \ Begin Date Decimal Day 216 1971 Sept 2 244 251 May 4 124 217 9 251 252 11 131 218 16 258 253 18 138 219 23 265 254 25 145 220 30 272 ; 255 June 1 152 221 Oct 7 279 256 8 159 222 14 286 257 15 166 223 21 293 258 22 173 224 28 300 259 29 180
225 Nov 4 307 260 July 6 187 226 11 314 261 13 194 227 18 321 262 20 201 228 25 328 263 27 208
229 Dec 2 335 264 Aug 3 215 230 9 342 265 10 222 231 16 349 266 17 229 232 23 356 267 24 236 233 30 363 268 31 243
234 1972 Jan 6 5 269 Sept 7 250 235 13 1:2 270 14 257 236 20 19 271 21 264 237 27 26 272 28 271
238 Feb 3 33 273 Oct 5 278 239 10 40 274 12 285 240 17 47 275 19 292 241 24 54 276 26 299
242 Mar 2 61 277 Nov 2 306 243 9 68 278 9 313 244 16 75 279 16 320 245 23 82 280 23 327 246 30 89 281 30 334
247 Apr 6 96 282 Dec 7 341 248 13 103 283 14 348 249 20 110 284 21 355 250 27 117 285 28 362
11 TABLE 2.
EXPLORER 47 (IMP-7) LOCATIONS FOR 1973
Date (1973) Time (UT) 0 (Solar Ecliptic Azimuthal Angle) Jan. 2 0200 2700 5 1300 00 8 0500 900 11 0730 1800 14 1930 2700 18 0030 00 20 2230 . 90 24 0000 1800 27 1300 2700 30 1300 0° Feb. 2 1830 90 5 1700 1800 9 0730 2700 12 0730 00 15 1500 90 18 0900 1800 22 0230 2700 25 0500 00 28 0830 90 Mar. 3 2230 1800 6 1930 2700 9 2100 0o 12 1900 90 15 1100 1800 19 1030 2700 22 0900 0o 25 0230 90 28 0200 1800 31 2300 2700 Apr. 3 1930 00 6 1100 90
12 REFERENCES:
Behannon, K.W., K.H. Schatten, D.H. Fairfield and N.F. Ness, Trajectories of Explorers 33,34 and 35 July 1966- April 1969 Goddard Space Flight Center document X-692-70-64 revised Feb. 1970.
Fairfield, D.H., and N.F. Ness, IMP-5 Magnetic Field measurements in the high latitude outer magnetosphere near the noon meridian, J. Geophys. Res., 77, 611-623, 1972.
King, Joseph H., IMP Series Report/Bibliography NSSDC 71-21 published by the National Space Science Data Center, GSFC, Greenbelt, Md 20771, 1971.
Mish, William, IMP-F and G Phase I Magnetic field analysis, GSFC document X-612-67-602 revised April 1972.
Ness, N.F., K.W. Behannon, C.S. Scearce and S.C. Canterano, Early results from the magnetic field experiment on lunar Explorer 35, J. Geophys. Res., 72, 5769-5778, 1967.
Scearce, C.S., N.F. Ness, and S. Cantarano, GSFC Magnetic field experiment Explorers 33 and 35, Goddard Space Flight Center document X-616-69-53, February 1969.
Scearce, C.S., C.V. Moyer, R.P. Lepping and N.F. Ness, GSFC Magnetic field experiments Explorers 47 and IMP-J, in preparation, 1973.
Seek, J.B., J.L. Scheifele, and N.F. Ness, GSFC Magnetic field experiment Explorer 43, to be published 1973.
13 FIGURES
Figure 1 - Solar ecliptic equatorial plane (XY) projections of Explorers 33 and 35, May 1969.
Figure 2 - Solar ecliptic meridian plane (XZ) projections of Explorer 33 and 35, May 1969.
Figures 3-20 - Explorers 33,35 and 41 (IMP-5) June 1969- Feb 1970,XY and XZ projections alternate.
Figures 21-32 - Solar ecliptic XY projectionsof Explorers 35 and 41 (IMP-5) March 1970-Feb 1971.
Figures 33-50 - Solar ecliptic XY projections of Explorers 35, 41 (IMP-5) and 43 (IMP-6) March 1971-Aug.1972.
Figures 51-54 - Solar ecliptic XY projections of Explorers 35, 41 (IMP-5), 43 (IMP-6) and 47 (IMP-7) Sept 72- Dec 72.
Figure 55 - Solar ecliptic XY and XZ projections of four Explorer 41 (IMP-5) orbits in the noon meridan plane spaced one year apart in time. The differences between the XZ projections indicate gradual changes in the orbit that are taking place in an inertial coordinate system.
Figure 56 - Solar ecliptic XY and XZ projections of two Explorer 43 (IMP-6) orbits in the noon meridan plane spaced one year apart in time. The differences between the orbits indicate the gradual changes in the orbit that are taking place in an inertial coordinate system.
14 10 12 - 6
14 -3D 26 24 27 2
-Io \3 206 16 26 XSE OD 7 SO D -3010X -50I_
MAY 116
18 30
.'s 30
20 28
22 24 26
FIGURE'1 YSE MAY 1969 70
50
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FIGURE2
s9o
FIGURE 2 zSE 10 -30
0 1
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XSE 170 1o I .ct~-W 1-50 .3-70 . 2 28 22 24 22 122 - SD
28 26
26 22 20 16UR33 tS 22 70 2
4 16
8 10 12
FIGURE 3 YSE JUNE 1969 1412 10
m24
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FIGURE 4 ZSE JUNE 1969 86
-50-Io 10
12 2 2I
3 -30 20.'23
too GD 100 5 -50-( 16 28~1
6
26
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12 26
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FIGURE 5 YsE JULY 1969 10 12 414
24 -Z0-50 10 12 20 12 20 14 16 18 6 8FIGURE -70
-9D
FIGURE 6 JULY 1969 6 4
2
10 30
6
12y 12/15 -22 5/9
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XE 7o - - 12 14 9to
2922
116 20 282 24 188
20\ 222 20 22 24 2628
FIGURE 7 S AUGUST 1969 .
10
so
90 70 30-2c I -oa.~Z a- la20 22 24
144 1622
1822 2022 -0
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Z1 FIGURE 8 AUGUST 1969 4 62 S- 7
10 8 12 1 R
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16 t10 Yd
Z88 188 70 12 so 3 10 ol -3o -SO 20 to
22
24 22B 2 14 26
28
a30 16422
18 20 2
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YSE FIGURE 9 SEPTEMBER 1969 so
z 30
FU 1270 0- 20222
30 0
8128
24 22
-70
Z SE FIGURE 10 SEPTEMBER 1969 I39 10 24 -
2 10
28 26
XSE 30
24
14
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4 1S
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FIGURE 11 YSE OCTOBER 1969 62 30 28
12 14 16 20
26 16 -70
24 22is 18
-0
.- 90
FIGURE 12 ZSE OCTOBER 1969 26 240
248
40 2
1022
30
2S 0. 00- . -7o
4
6 822 12
20 14
16 Is
F3E FIGUE13NOVEMBER 1969 82
SE 80 -7 -0
-70 28
20 4 122
26 6
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FIGURE 14 ZSE
NOVEMBER 1969 NOVEMBER 1969 30 28 a
64
22 4 30
so0 6
4 16 26
6 DE 0MBR 1969 .25 28. 14 242
XSE .soa 70 0o -1 . -s0 -1
22 12 10
12
20
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YSE FIGURE 15 DECEMBER 1969 10
XSE 90(-_2 ,4 0 30 -3 21 - 2 70 --
-1
4 22 0
FIGURE 16 DECEMBER 1969 2
4 -70
2 6 30
o 28 30 4
228 26
-30 26
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XSE 10 - '22 so 70 8 50 0 '7' -30p -5 0 -70 -90 14:1022 a:17 6 31 20 12
18 10 20 16
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14 16
FIGURE 17 Ys JANUARY 1970 so
12
10
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4 16 22 so o 6 4 30 o -10 0o2
-0 2
-o
FIGURE 18 ZSE JANUARY 1970 -70 2
2 28
43 24
22
1. to 28
18 122 g 20
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12 14 to
9 0
YSE FIGURE 19 FEBRUARY 1970 30
12 104 16 18
6
-26
FIGURE 20 FEBRUARYZng 1970 -70
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XSE 70 so 3D a so -so -7
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FIGURE 21 YSE MARCH 1970 .- 10
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2 *5-to
lo I aa io Ib a-o I -oI I22
r2.9 414
YSE FIGURE 22 APRIL 1970 XSE I- 6
22
10
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FIGURE 23 YSE MAY 1970 -70-o
26 28 -50 30
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4 SSE so FIGURE 24 I -- so
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YSE FIGURE 24 JUNE 1970 -go
26
28 24 . so
22 0
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2
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6 30a
16
8 .s F RU1 14
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YSE FIGURE 25 JULY 1970 -30 3090 30
Yso
FIGURE26 AUGUS 9
2 22
10
FIGURE 26 AUGUST 1970 20
28 23
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2
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4
12
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FIGURE27EPEMBER 19 FIGURE 27 SEPTEMBER 1970 -70 22 24 20
26
is
418
16
28
30 12
6 10 8-
70
YSE FIGURE 28 OCTOBER 1970 22 20
24 Is
26 16
29
28 I 14
XSE so 70 30 to -30 -SO0-70 -0
to
30
2
0
8§ 6 1
70
YSE FIGURE 29 NOVEMBER 1970 -'0
22 20
18 24 -so
16
26
28 c -0
SOO
50 +o21
. .2o 28
4 6
YSE FIGURE 30 DECEMBER 1970 2
22
24
-r
26 .- 10
m a 12 o22 70~~ to -W21
300
YSS 6 So-
Yse
FIGURE 31 JA.Rl~v ,971 FI GURE 31 JANUARY1971 -50
20 16
22 14
-lo
260 176 10
184 25
28
27 4
Y FIGURE 32 SE FEBRUARY 1971 -10o
20 18 22
16
24
XSE so 2 ~ ~O0 v IMP 6
IMP 5
30
2
FIGURE 33 SE MARCH 1971 -u
20
22
24 f30-
Sh a so I
28 IMP 5
30 2
e
APRIL 1971 APRIL 1971 18 16 20
14
22
IMP 6 , .*,
24
SE so -30 -SO -m -90 10 to
30 26 M20 3 0
28
5o 6/
30 2
J on
YSE FIGURE 35 MAY 1971 -90
16
W 14
20 IMP 6 12
22
OD70UE - -? -0
6 raa IMP 5 6%1o i2 24 .2
26 6
28
FIGURE 36 JUNEYsE 1971 16 14
12 IMP 6
20 I . 2 26
34 22 IMP 5 1 3
SE 6SE
24RE37
26
30 9
YSE FIGURE 37 JULY 1971 -mo
-10
14 12 16
10
3 6IMP 6
IMP 5 14'15 8 20 5.-9
X SE FGRo 8 i3 -so m
22 6o
24
30 28
YSE FIGURE 38 AUsT 1 16
IMP 5
215
18
11
*22 a,01 1t I sl 10 ,- - I , I -92 20 ~- 4
2
26 .
FIGURE 39 SEPTE68ER 1971 FIGURE 39 SEPTEMBER 1971 12 10 14
\
202.
x ILI \5
177 4 162620 to 28 .2125I IMP6M 25 IMP 6 2 9
@ 6n
30
SE 24 t.9 -10SE FIGURE 40 OCTOBER 19713 26 T-28
y SE FIGURE 40 OCTOBER 1971 16 14 IMP 5
56 14
6 NO TRACKING 4
18 XSE so Itoo -ICa -30 -50 -'m -90
20 l15 IMP 6
8 27
2
FIGURE 41 YSE NOVEMBER 1971 10
12 -
lo 14/
16
n .,18 mD'. a Po nl \-Po mo
20 . 10T2 iei IMP2'o 6
22 28
24-L- 26
IGURE2 DECEMBER 1971 108 i6 11 4
14 -0
2 -10 16 --o
TRACKING
IMP6 I2
22 24
YSE FIGURE 43 JANUARY 1972 8l 6
14
XSE *r r , ,D ,' 10 '
to
,*6 27 F. I,6I lIMP 5 IMP 6 1814
to 79
20 24
22
.70
SOD
FIGURE 44 SE FEBRUARY 1972 12 4
14 23. 30
SE so 70 so 27.a 10o -so- -
16 9d. 14* to IMP 6 10 2 8
18 IMP 5
26
20 24 22
YSE FIGURE 45 SE MARCH 1972 -70
8~ 6
4 10 -
30 21.29 . -1o IMP 6 1]?
FIGURE 46 E26
20APRIL1972 2 7 20 IMPIMP 611
9 -10 29 3
XSE to m 30 -30 -50 -70
to
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FIGURE 47 4 SE MAY 1972 4
-2
IMP 6 30 26
28
XSE ... so 3000 -3 -so -70 12 27 2117 26 IMP 5 14
14 24
22
Is 20
FIGURE 48 YSE JUNE 1972 4
6 2 -so
8 IMP 6
4 9,1 7 25 28
10 30O 24i 17**21 SEF I 7 -30 -50 -70 IMP 5 4. 26
12
30 24
14
Sso /22 OJUL 1972 16 20 18
mj
FIGURE 49 YSE JULY 1972 4 30
6 28
II i MPI
XSE o - 4
10 to 24
12 22
14 20
16 18
FIGURE 50 AUGUST 1972 29
22 S3 -
IMP 5 -3
. 13l7 IMP 6 7------. .17
XSE 10 w to to @ 30_30 23 S102 F1E
9 27 ,
IMP 7 -- 29
.a 19
15
so
YSE FIGURE 51 SEPTEMBER 1972 -10
29
I *-x "25
x @( S IMP-5
I 15
72 9'2 23
X11
I
,3\
YSE FIGURE 52 OCTOBER 1972 29 27
225 _ i 13---.
,X' 27x" 25 2 2 x v
34 290- 0 so xw- -1 I X S£ 29x * x I 5 o a ar l a 2951 a bse 3.9
IMP-7 o51' .'s19 "s U s~ 19 7
NOVEMBER 1972
13 15
FIGURE 53 YsE FIGURE 53 S NOVEMBER 1972 --70
29 .. _27
31-50 25
- 20
3 7 23 /X22 - 30
10 \o-31
DEC 23 I/ X23 2 I 5 I\x18 / o5130 21 70 50 1 24 30 10 -0 - XSE I I I iX I I I I XSE xi7
\IMP 6 4/ 6 7 x 6 / 25 x/
IMP 7 \ 6
9
-50
15 13
-70
YSE FIGURE 54 DECEMBER 1972 YSE
-2
-- ORBIT 5 JULY 6, 1969 ----- ORBIT 114 JULY 8, 1970 8
--- ORBIT 222 JULY 7, 1971 ------6 ---- ORBIT 331 JULY 7,1972 4 4
.2 30 20 10 XSE
-2
-6 -8
IMP 5 IN SOLAR ECLIPTIC COORDINATES ZSE FIGURE 55 YSE -5 ORBIT 94
XSE 30 20 10
ORBIT 5
APRIL i, i971
ORBIT 94 ZSE APRIL 4,1972 +5
XSE 30 20
-5
IMP 6 ORBIT IN SOLAR ECLIPTIC COORDINATES FIGURE 56 r7