Gaojing problems explained

After launch performed on 28 December it was not clear which orbit was reached by upper stage of Long March 2D and where exactly Gaojing-1-1 and Gaojing-1-2 were deployed. Now we know -   two remote sensing  satellites missed their orbit.

First assumption proved to be true - in fact both Gaojing failed to reach correct orbit and finally they were located on lower orbit - 213 km x 524 km and inclined at 97.6°. Secondary 2U sized CubeSat BY-70 satellite also failed to reach correct orbit, but its condition was confirmed before Gaojin-1-1 and Gaojin-1-2; BY-70 was also deployed on 520 km x 220 km orbit. After few rather tough hours for flight engineers and specialists on mission control center yesterday, satellites confirmed their condition and deployed solar arrays. During same time, when specialists were trying to evaluate condition of satellites, TV news reports showed available telemetry data - it was clear, that rocket suffered for delayed first stage separation (for about 7 s, at T+2'43") and delayed MECO of second stage for 10 s (at T+5'32"). With telemetry data we could assume, that first stage failed to give specified speed for the rocket. It forced prolonged burn of central engine of the second stage (YF-22C)  and shorter burn of four vernier YF-23C engines. Reaching too low orbit resulted in necessity of increasing perigee with own propulsion of satellite. In last 24 hours (position from 08:21 UTC on 29 December) Gaojin-1-2 has changed its orbit for almost 40 km from 214 km x 520 km to 242 km x 520 km what clearly shows, that engineers decided to sacrifice 8 years of mission duration for reaching orbit - burning fuel to reach orbit means, that satellites will not have sufficient amount of propellant to keep stable orbit during mission. In case of Gaojing-1-1 it was not unveiled if satellite already started orbit raise maneuver or not. It is possible that satellite will begin maneuver later. It is worth to remind, that planned orbit for both Gaojing satellites was SSO with altitude of around 500 km - to change altitude for approx. 200 km, satellite probably will need around 5 days.

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