3 ms·

Here's [1] a data graph of the Doppler curve from Dwingeloo Radio Telescope (based in Netherlands) showing the exact moment the probe crashed into the surface o

Here's [1] a data graph of the Doppler curve from Dwingeloo Radio Telescope (based in Netherlands) showing the exact moment the probe crashed into the surface of the moon. https://twitter.com/cgbassa/status/1170072672266592256 https://twitter.com/cgbassa/status/1170072672266592256

baybal2 7y ago
It bounced back?
mkagenius 7y ago
I am confused, the contact with ISRO was lost at 2.1 km height (as per ISRO's last night statement). So, not at 0 km height (crash) ? Edit: I meant contact with ISRO..
- penagwin 7y ago
  This isn't contact per-say, the telescope wasn't in communication with the probe, it was just watching it r.
- dvdbloc 7y ago
  This is all speculation but it could be buffering or it was tumbling so quickly that antenna switching couldn’t keep up or worst case, a RUD
jcims 7y ago
Any RF experts in here kniw what that cirrus cloud effect on the center transmission could be? Good view here: https://twitter.com/cgbassa/status/1170069055140765700?s=21 https://twitter.com/cgbassa/status/1170069055140765700?s=21
- sandworm101 7y ago
  The blur is because the vehicle was vibrating. It means the thrusters were on. Note how they smooth out shortly after deceleration stops. Some of the larger movements could be maneuvering. If it is orientating itself then the antenna would intermittently move back and forth relative to the receiver.
  - jcims 7y ago
    I was thinking vibration but wouldn't we see a change when the retro-thrusters hit halfway through? I'm assuming the first part with downward slope is the craft accelerating due to gravity? Given it's a polar landing I don't know how to translate this to the velocity vector of the lander.
    - sandworm101 7y ago
      I think the change at the haldway mark is the thrusters stopping. The lander would continue shaking for a few seconds afterwards.

3 ms·

Here's [1] a data graph of the Doppler curve from Dwingeloo Radio Telescope (based in Netherlands) showing the exact moment the probe crashed into the surface o

by abhiminator 7y ago

baybal2 7y ago
It bounced back?
mkagenius 7y ago
I am confused, the contact with ISRO was lost at 2.1 km height (as per ISRO's last night statement). So, not at 0 km height (crash) ? Edit: I meant contact with ISRO..
- penagwin 7y ago
  This isn't contact per-say, the telescope wasn't in communication with the probe, it was just watching it r.
- dvdbloc 7y ago
  This is all speculation but it could be buffering or it was tumbling so quickly that antenna switching couldn’t keep up or worst case, a RUD
jcims 7y ago
Any RF experts in here kniw what that cirrus cloud effect on the center transmission could be? Good view here: https://twitter.com/cgbassa/status/1170069055140765700?s=21 https://twitter.com/cgbassa/status/1170069055140765700?s=21
- sandworm101 7y ago
  The blur is because the vehicle was vibrating. It means the thrusters were on. Note how they smooth out shortly after deceleration stops. Some of the larger movements could be maneuvering. If it is orientating itself then the antenna would intermittently move back and forth relative to the receiver.
  - jcims 7y ago
    I was thinking vibration but wouldn't we see a change when the retro-thrusters hit halfway through? I'm assuming the first part with downward slope is the craft accelerating due to gravity? Given it's a polar landing I don't know how to translate this to the velocity vector of the lander.
    - sandworm101 7y ago
      I think the change at the haldway mark is the thrusters stopping. The lander would continue shaking for a few seconds afterwards.