The most important times extracted from the tracking station timeline for today’s AOS: acquisition of signal. The usual disclaimer: All times subject to change! Today, CET = UTC +1 hour
| UTC | Event |
| 10:00 | WAKE UP (2:00 am PST) |
| 14:35 | NASA DSS-14 (Goldstone 70m) BOT (Begin of track) – watching for signal just in case |
| ~17:00 | Rosetta turns on S-band transmitter (45 min OWLT – one-way light time for signal to reach Earth) |
| After 17:30 – from this time on all Rosetta times estimated | |
| ~17:45 | NASA DSS-14 captures carrier signal |
| ~18:10 | Uplink command to ROSETTA to turn on telemetry (i.e. start downloading data) |
| 18:15 | DSS-43 (Canberra 70m) BOT |
| ~18:55 | Rosetta turns on telemetry |
| ~19:40 | First telemetry data captured at DSS-14 and DSS-43 |
| 20:34 | ESA DSA1 (New Norcia 35m) BOT |
| 21:45 | Turn off DSS-14 uplink transmitter |
| 21:50 | Turn on DSS-43 uplink transmitter |
| 21:50 | DSS-14 End of Track (EOT) |
PS: Quick answer to @Chris_Bloke from ESA’s Daniel Firre, one of our tracking station experts.
@esaoperations @_space_facts_ what network protocols do you use? TCP would be limited by round trip time certainly.
— Chris Samuel (@chris_bloke) January 19, 2014
From spacecraft to ground (and vice versa) we rely on space communication standard for packet telemetry and telecommand on top of CCSDS channel coding standard. For moving data around between the ground stations and the control center here in Darmstadt, we use CCSDS Space Link Extension standard implemented on TCP-IP.
Discussion: 12 comments
Will Rosetta start tx’ing at 1000UT on S-Band or on X-Band?
S-band. Will not switch to X-band for at least 2 hours after AOS.
Hi Daniel, thanks so much for taking the time to answer my query from Twitter!
Looking at the CCSDS website this appears to be the protocol specification, would that be correct?
https://public.ccsds.org/publications/archive/232x0b1s.pdf
Thank you again!
Chris – @chris_bloke
Will ask!
Chris: From our EStrack expert Daniel Firre:
The one you mention is part of the story, yes. It covers the telecommand protocole with acceptance and retransmission whenever required.
The standards I am referring to, in full, are :
CCSDS Packet telemetry (102.0-b)
CCSDS telemetry channel coding (101.0-b)
CCSDS telecommand channel (201.0-b) and data routing (202.0b)
CCSDS Space Link extension (set of standards in the range 910/911/912)
Great, thanks so much!
O.k., telemetry should start to arrive ~19:40 UTC: by when (or by which day) would you, assuming nominal operations, be in a position to state that the spacecraft itself (not talking of the payload or Philae) is healthy?
Daniel: Andreas said yesterday they’ll already have a very good overall idea of s/c health later this evening. Instruments & Philae must wait. Cheers!
Hi Daniel, will the S-band transmitter be on again on Tuesday morning, when ROSETTA will be visible over Europe? Cheers and good luck, Edgar
Hi Edgar: Will ask!
Normally not. S-Band will be commanded off at some point once stable and reliable X-Band links are secured over the ESA Station at New Norcia, Western Australia. This will happen some time during the New Norcia pass tomorrow morning around 03:15 GMT.
Hello Daniel,
what a challenge, we keep our fingers crossed!
Ursula and Helmut