Philae Wakes Up! Options

[chuck0]

We didnt hear anything form the mission today... i just hope that they dont run into another safe mode. The Startracking failure graph they showed at the last press conference was pretty scary.



The blue line represents how many issues there have been with the star trackers and the dotted grey one is the distance to the comet. X-Axis is comet distance to the sun... Even when they kept far away from the nucleus the star trackers now seem to have tons of problems so close to the sun.

[ollopa]

I note that people are still commenting on the http://isee3.p3s.nl/philae/ data. My understanding is that this has NO relation to actual Philae data. The webmaster told me as much a week ago. Unless someone can cite a recent confirmation that this is now reliable, I suggest it cannot be relied upon.

[Herobrine]

Well, I quoted several tweets from @DutchSpace (mentioned at the top of the telemetry page) several posts back in this thread, but maybe seeing is believing.

https://twitter.com/DutchSpace

[chuck0]

I assume this guy is the web master right?

https://twitter.com/DutchSpace/status/612539793386401792

as far as i understand it there are only a few variables updated properly right now. The whole upper graph is useless (is this what you mean when you said "the webmaster told me as much"? ). The only relevant stuff are some of the current measurements in the lower one ( PSSH_C_SBat_CH and PSSH_C_SBat_DCH are current from the solar panels and the recharchable battery discharging current). If this is not really data from Philae then it at leasts corresponds nicely with the times contact was reported...

[alphasam]

Makes sense that Philae could have shifted. I believe though the CONSERT antenna projects off the lower part of one of the sides, unless there's another reason the head (top) would be important.

Philae communicates through an S band antenna on the head. It has a visibility cone of 60 degrees to the positive z (straight up). So if Philae is pointing to the ground....

[Herobrine]

For what it's worth, the bottom graph at http://isee3.p3s.nl/philae/ is fed by the same data source as http://www.musc.dlr.de/philae/telemetrie.html (the science sequence graph is the only one that includes the new data), but the isee3 page has a much easier-to-use graph and is being maintained (for example, over the weekend the lower graph was relabeled). The data that feeds the bottom graph on the isee3 page can be accessed at http://www.musc.dlr.de/philae/db_pss-statu...h_v_sbat-c.json and the data that feeds the bottom graph of the DLR page can be accessed at http://www.musc.dlr.de/philae/db_curent_5_...h_v_sbat-c.json (this is the exact same data as the other one, but with the pre-landing data omitted).

[scalbers]

If Philae is still pointing as in this mosaic, we can see the top of the lander is aimed generally at (or a bit left of) Perihelion Cliff (green dot in center of yellow solar circle). Thus I wonder if Rosetta is possibly being maneuvered to catch the line of sight pointing just above Perihelion Cliff, thus at a latitude more to the north? This would actually not be at the zenith of Philae's latitude. North is in the center of this mosaic.



Is there a way to check Rosetta's current latitude? How much of the 60 degree cone is pointing above Perihelion Cliff? Is alphasam's 60 degree figure an angular radius?

[Herobrine]

Well, I've tried at multiple points during the day today and every time, I've found that the data sources the isee3 page uses for Philae telemetry ( http://www.musc.dlr.de/philae/db_pss-statu...h_v_sbat-c.json for the power systems) are now 404ing. If you've been watching it to spot new data from Philae, you can still use the URL the DLR telemetry page uses ( http://www.musc.dlr.de/philae/db_curent_5_...h_v_sbat-c.json ). It has contained identical data to the other one, with the exception that the data set doesn't include pre-landing data.

[Herobrine]

I see 4 new data points in the telemetry (the battery data, specifically), with the following timestamps:
2015-06-24 17:24:11
2015-06-24 17:28:35
2015-06-24 17:33:00
2015-06-24 17:37:24
Prior to these, the last data point had a timestamp of 2015-06-21 02:44:16.
Hopefully, this means we'll be hearing that contact was made today.

The raw data corresponding to the 5 data points I mentioned (including the last one from the contact several days ago):

CODE

1434854656879,28.7708,24.4642,0,0,2.855,2.312,41.34,1.26,38.85,356.314,220.968,1
.085,1.09,28.908
1435166651336,0.04275,0,0,0,3.997,3.468,27.56,0,5.25,384.958,11.016,0.868,0.872,
0.876
1435166915804,28.7024,28.8982,0,0,2.284,2.312,9.54,25.2,35.7,389.732,20.304,1.30
2,1.09,0.876
1435167180367,28.7024,28.9642,0,0,2.284,2.312,55.12,0,34.65,381.052,26.568,0.868
,0.872,0.657
1435167444992,28.8563,28.8836,0,0,1.713,1.734,9.54,55.44,38.85,386.911,35.64,0.8
68,0.654,1.314

[chuck0]

Thanks for posting this data! Was already wondering whether they disabled the public api completely.
I guess since there are only four new data points they are still struggling to get a stable connection. I wonder if they will consider leaving the terminator plane to get a longer communication window...

[scalbers]

Wouldn't the latitude they are stationed or orbiting at be more of a factor than being on the terminator plane (as per post #97)?

[chuck0]

Right lattitude has to be really important as well. Since Philae can currently only communicate when it gets sunlight i would assume that the optimal position for getting a long communication window would be between the sun and the comet and at the lattitude of the lander... Btw, according to malmers page Rosetta is now at 170km and still in the terminator plane.

[scalbers]

Good point about sunlight communication constraints relating to relative longitude and being at that longitude near local noon. My point was that if the lander is highly tilted towards the north, then the latitude of Rosetta should correspondingly be more north as well to line up with the antenna. However not so far north that Perihelion Cliff gets in the way. It might be a sweet spot and a bit less than ideal if Philae's antenna happens to point below the top of Perihelion Cliff.

[katodomo]

I doubt they'll move Rosetta out of the terminator plane anytime soon - for safety reasons.

[fredk]

What reasons? If they move out of the terminator plane, then for part of an orbit they will be "upwind" and "downwind" of the nucleus from the sun. The sun-facing side of the nucleus might be expected to release more particles than the night or terminator areas. And the solar wind will eventually push particles downwind. So it might seem like the terminator plane would have the fewest particles.

But are inner comas that asymmetric? Maybe the concern is that very powerful jets may yet erupt and are more likely to point sunwards?