ARTEMIS II Mission

One needs some luck to get the surpise to see the signal! Two nights ago I was out of luck. The strong winds had tilted the elevation up, and the pointing of the dish was off track. I use a “fixed” pointing of about 8 degrees elevation heading south.

Last night was full of surprises. I was surprised that I received the signal while the space craft is getting close to the Moon. And I was lucky that they used some transmit modes with a strong carrier for a short period while Integrity was in my beam. I used a smaller bin size of 25 Hz instead of the 100Hz I used earlier, because the Doppler change is slowing. I have tuned the colors of the plot to bring out the signal:

Next luck is that Space Track published another TLE:

0 ARTEMIS 2 (INTEGRITY)
1 68538U 26069A   26095.31257403 -.00058714  21969-3  00000+0 0  9995
2 68538  56.3581  51.2608 9964302  34.1676  95.2444  0.11783130    15

Another surprise is the inclination. It has changed from 28 to 56 degrees. Apparently the flight path is more dynamic then I thought!

This TLE fits nice to the data:

The RMS error is only 27Hz. But the updated TLE does not fit the earlier period when it was close to Earth and had just performed the TLI burn:

Fingers crossed for tomorrow!

5 Likes