As many of you know, last week we fired the thrusters on ISEE-3 to do a spin-up burn. Before the burn (actually 11 pulses on the spacecraft’s hydrazine thrusters) the spin rate of ISEE-3 was 19.16 rpm. After spin-up burn it was 19.76 rpm. The original mission specifications for ISEE-3 called for a spin rate of 19.75 +/- 0.2 rpm. In other words: bullseye.
If all goes according to plan on Tuesday, 8 July, we will conduct the Trajectory Correction Maneuver (TCM). This will require a much longer firing of the spacecraft’s thrusters. Â Our window at Arecibo opens at 12:42 pm EDT and extends until 3:29 pm EDT. If the burn is a success we will follow up with another ranging session using the DSN to get an exact measure of the spacecraft’s position, trajectory, and speed. Â After that we should be good to go for our lunar flyby on 10 August.
After the last technical tag-up for today it looks like TCM will be 432-435 pulses fired in 7 segments with a total delta V of approximately 7 m/sec.