Friday, October 5, 1984

Pioneer 4

   1959-013A


The second JPL/ABMA probe, Pioneer IV, again nominally a NASA launch, was launched by Juno II at 0510:56 on 1959 Mar 3. The Jupiter cut off at 0512 and separated 5s later. The Jupiter guidance section remained attached to the Cluster (JPL Cluster 12). Next the nose fairing was separated, and then the Stage 2 fired, separating from the Cluster rotational launcher fixed to the Jupiter guidance section. The remaining stages fired in quick succession, and separated from the payload. The payload was then despun from 416 revs per min to 11 rpm using release masses on wires. Low performance resulted in missing the Moon, but achieving solar orbit. At 2224 on Mar 4 Pioneer IV passed the Moon at a distance of 60600 km and sailed on into solar orbit.

The final stage (motor serial TC-25) and the despin weights also entered solar orbit. It stopped transmitting after 82h, at around 1500 on Mar 6, at a range of 669000 km. It reached perihelion on Mar 17 and aphelion on Oct 1.


Pioneer 4 
 

DateTimeEventOrbit  

1959 Mar 3  0510:56  Launch by Juno II 
 0513:09  Spinup Cluster 
 0514:00  MECO T+3:03 
 0514:05  Jupiter sep T+3:09 
 0514:18  Nose fairing sep T+3:22 
 0514:59  Stage 2 burn T+4:03 at 178 km 
 0514:59 Jupiter guidance section sep 
 0515:04  Stage 2 burnout  -2900 x 1000? x 29.0 
 0515:09  Stage 3 burn T+4:12 
 0515:19  Stage 3 burnout  -424 x 4608 x 29.0 
 0515:19  Stage 4 burn T+4:23 
 0515:26  Stage 4 burnout T+4:29, 227 km 
 0515:33  Stage 4 sep  -45 x Inf x 29.0 
   -26 x -393254 x 29.0  
 1632:34  Despin payload 
1959 Mar 4  2224  Lunar flyby
 2301  Perilune 60600 km 

1959 Mar 6  

1530end of transmissions
1959 Mar 17   Perihelion 147.6 Mkm, i = 0.20 deg (ec) 
1959 Sep 10   Ascending node 
1959 Oct 1   Aphelion 170.3 Mkm 

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