Vanguard 1

Orbit facts

Year/Date Incli. Period Perigee Apogee
58-03-17 34.25° 134.18 min 650 km 3968 km
59-05-23 34.25° 134.01 min 657 km 3936 km
59-07-11 34.24° 134.21 min 653 km 3958 km
59-10-06 34.25° 134.03 min 657 km 3938 km
59-10-25 34.25° 134.13 min 655 km 3949 km
59-12-07 34.25° 134.24 min 655 km 3958 km
60-01-07 34.25° 134.13 min 657 km 3946 km
60-09-05 34.24° 133.98 min 649 km 3942 km
60-11-23 34.24° 134.03 min 650 km 3944 km
61-03-28 34.25° 134.07 min 658 km 3940 km
62-01-22 34.25° 133.94 min 649 km 3939 km
62-02-16 34.25° 134.06 min 653 km 3945 km
64-08-11 34.25° 133.99 min 651 km 3940 km
67-01-01 34.23° 133.97 min 650 km 3940 km
69-05-23 34.25° 133.90 min 650 km 3934 km
72-01-29 34.26° 133.84 min 652 km 3926 km
75-01-02 34.25° 133.82 min 651 km 3926 km
78-01-02 34.24° 133.81 min 655 km 3921 km
79-10-01 34.26° 133.74 min 650 km 3920 km
80-12-24 34.24° 133.61 min 652 km 3906 km
82-04-06 34.23° 133.54 min 652 km 3901 km
83-06-17 34.26° 133.47 min 651 km 3896 km
86-01-06 34.24° 133.46 min 651 km 3894 km
89-01-01 34.25° 133.43 min 651 km 3892 km
90-03-29 34.24° 133.30 min 652 km 3880 km
91-07-31 34.24° 133.23 min 651 km 3875 km
92-04-03 34.24° 133.16 min 654 km 3865 km
95-01-01 34.25° 133.12 min 651 km 3865 km
98-01-02 34.25° 133.10 min 650 km 3864 km
00-07-18 34.25° 133.03 min 650 km 3859 km

Drag has brought down the apogee and perigee, resulting in a decrease in period. Vanguard I's orbital history illustrates the phenomenom of drag bringing down apogee much more than perigee.