Posts: 3221 From: Belfast, United Kingdom Registered: Feb 2002
posted 11-15-2014 01:36 PM
quote:Originally posted by Robert Pearlman: That first sequence took up the full 50 to 60 hours of battery life Philae had upon landing.
So the "first sequence" was also the "last sequence." Thank you for clarifying this, but perhaps you will understand the slight confusion of someone who earns his keep interpreting the precise meaning of words.
moorouge Member
Posts: 2481 From: U.K. Registered: Jul 2009
posted 11-15-2014 02:09 PM
I'm still confused. This is from the ESA site and would seem to suggest that all the planned data was retrieved.
In that time, the lander returned all of its housekeeping data, as well as science data from the targeted instruments, including ROLIS, COSAC, Ptolemy, SD2 and CONSERT. This completed the measurements planned for the final block of experiments on the surface.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 11-15-2014 02:16 PM
To help clarify, all of the data collected by Philae during its battery-powered time on the comet was successfully relayed to Rosetta for transmission back to Earth. That data represented the "first block" or "first sequence" of science, a full run through of the lander's 10 instruments.
Had the lander been able to recharge its batteries using its solar panels, then the plan was to conduct additional blocks or sequences of science.
During its time active on the surface, Philae conducted 80 to 90 percent of the science that was originally planned. The full complement was not accomplished given the time spent assessing its condition after unexpectedly bouncing.
moorouge Member
Posts: 2481 From: U.K. Registered: Jul 2009
posted 11-16-2014 05:30 AM
I think that to be absolutely clear about this one needs to understand that any second (final) sequence of data received from Philea was to be regarded as a bonus. As I understand it, all the main objectives of the mission were to be achieved on the battery power alone. Anything else that might have come from the use of the solar panels to extend the operation of the probe was over and above these aims and as such it is slightly misleading to assert that there was a definite expectation that there was to be a 'second phase'.
In the event, this didn't happen but, nevertheless, Philae did complete its planned mission.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 11-16-2014 08:47 AM
That's not entirely accurate. ESA provided the timeline for Philae's "first science sequence" in this entry published Nov. 10 on the Rosetta blog.
The duration of the first science sequence that can actually be executed depends on the lifetime of the primary battery. If solar power is available to recharge the secondary battery then this may mean the full sequence can be executed.
The first science sequence (FSS) was to then be followed by the long-term science (LTS) phase, as described in this Sept. 13 Rosetta blog entry.
Power and battery recharging permitting, there is the prospect of continuing science operations on the comet surface for the long-term science (LTS) phase, which could run from November until March 2015. The emphasis during this period will be on studying how the conditions and environment at the landing site change as the comet gets closer to the Sun, and to make some additional studies that are among the more challenging of Philae’s science goals. These include searching for comet quakes with SESAME, using COSAC to look for evidence of amino acids in a drilled sample, and making tomographic measurements with CONSERT, by transmitting radio signals between Philae and Rosetta through different parts of the interior of the comet to look for heterogeneity on smaller scales.
The FSS was certainly the primary science planned, but to call the LTS only a bonus is, I think, inaccurate. The Philae lander team had plans to operate the probe longer than its initial battery life. The off-nominal landing precluded that, though.
Blackarrow Member
Posts: 3221 From: Belfast, United Kingdom Registered: Feb 2002
posted 11-16-2014 11:13 AM
Being a simple soul, there are really only two things I want to know about Philae's results:
When can we see the "final" enhanced images of the landing site? To date, apart from the stunning image of the rock-face looming above the landing-leg, the surface imagery could diplomatically be described as enigmatic. Is there no image showing a horizon? Were no additional images taken other than the six(?) I think I have seen on news coverage but am apparently not allowed to study individually?
Was a rock-sample successfully obtained by the drill? Was it successfully delivered to the "Ptolemy" analyzer? Were the analysis results successfully AND COMPLETELY transmitted back to Earth? (I'm not asking for the results: I just want to know that the data has been received).
Well?
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 11-16-2014 11:35 AM
Historically, ESA has been reluctant to release full imagery collected by its probes until they have been fully processed and analyzed. The images released thus far have been posted to ESA's Flicker set here.
The six photos do show the horizon/sky above the lander. This labeled graphic may help.
As for the drill, they know it activated but whether it collected any samples and if so, was analysis conducted is still to be determined and/or reported.
According to ESA, the first science results from Philae will be revealed during the American Geophysical Union fall meeting to be held Dec. 15-19 in San Francisco.
Blackarrow Member
Posts: 3221 From: Belfast, United Kingdom Registered: Feb 2002
posted 11-16-2014 05:35 PM
Thanks, Robert. You are, as always, a mine of information. I suspect the "horizon" in the graphic is a little fanciful, but at least we won't have to wait too long for enlightenment. (Unlike Philae, sadly!)
posted 11-16-2014 08:05 PM
Congrats to the entire ESA Rosetta team!
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 11-17-2014 09:42 AM
European Space Agency photo release
OSIRIS spots Philae drifting across the comet
These incredible images show the breathtaking journey of Rosetta's Philae lander as it approached and then rebounded from its first touchdown on Comet 67P/Churyumov–Gerasimenko on 12 Nov. 2014.
The mosaic comprises a series of images captured by Rosetta's OSIRIS camera over a 30 minute period spanning the first touchdown. The time of each of image is marked on the corresponding insets and is in GMT. A comparison of the touchdown area shortly before and after first contact with the surface is also provided.
The images were taken with Rosetta's OSIRIS narrow-angle camera when the spacecraft was 17.5 km from the comet centre, or roughly 15.5 km from the surface. They have a resolution of 28 cm/pixel and the enlarged insets are 17 x 17 m.
From left to right, the images show Philae descending towards and across the comet before touchdown. The image taken after touchdown, at 15:43 GMT, confirms that the lander was moving east, as first suggested by the data returned by the CONSERT experiment, and at a speed of about 0.5 m/s.
The final location of Philae is still not known, but after touching down and bouncing again at 17:25 GMT, it reached there at 17:32 GMT. The imaging team is confident that combining the CONSERT ranging data with OSIRIS and navcam images from the orbiter and images from near the surface and on it from Philae's ROLIS and CIVA cameras will soon reveal the lander's whereabouts.
Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 11-18-2014 07:29 AM
DLR has reported that that Philae found a hard surface and organic molecules on the comet:
The team responsible for the MUPUS (Multi-Purpose Sensors for Surface and Sub-Surface Science) instrument, which hammered a probe into the comet, estimates that Comet 67P is hard as ice: "Although the power of the hammer was gradually increased, we were not able to go deep into the surface," explains Tilman Spohn from the DLR Institute of Planetary Research, who is leading the research team.
...COSAC was able to 'sniff' the atmosphere and detect the first organic molecules after landing. Analysis of the spectra and the identification of the molecules are continuing.
John C UK Member
Posts: 23 From: Registered: Aug 2014
posted 12-01-2014 02:07 PM
I have just posted an exclusive "Behind the Mission" interview with an engineer who worked on Rosetta on my STEM Ambassador blog.
It's fascinating!
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 01-06-2015 10:24 PM
quote:Originally posted by Blackarrow: Was a rock-sample successfully obtained by the drill?
"It [the drill] didn't deliver any sample," Paul Weissman [a Rosetta program scientist at NASA's Jet Propulsion Laboratory in California] told Space.com after his talk here at the 225th meeting of the American Astronomical Society yesterday (Jan. 5). "That's all I know. We do have measurements from those instruments and all they're measuring is what we see in the atmosphere. They're not measuring any solids."
In related news: the Rosetta team has still not been able to locate Philae on the comet's surface.
Efforts to find Europe's lost comet lander, Philae, have come up blank.
The most recent imaging search by the overflying Rosetta "mothership" can find no trace of the probe.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 01-16-2015 05:33 PM
quote:Originally posted by Robert Pearlman: Historically, ESA has been reluctant to release full imagery collected by its probes until they have been fully processed and analyzed.
It would seem that the slow pace at which Rosetta images have been released may be the catalyst for seeing a chance in the way the European Space Agency handles mission photos. From BBC News:
The European Space Agency needs to find a new way for images and other data acquired by its science missions to come out into the public domain.
That is the view of the organisation's director general, Jean-Jacques Dordain.
He was expressing his frustration at not seeing more pictures from the main camera system on Esa's Rosetta probe, which is tracking Comet 67P.
These images are subject to a six-month embargo to allow the mission team to make discoveries without being scooped.
But the policy has upset the thousands of ordinary members of the public who follow Rosetta on a daily basis because they are not being shown the very best views that have been acquired.
Nearly all of the images seen to date have come from the probe's navigation cameras. The products of its science cameras, on the other hand, which are far superior, have been given only a very limited release because of the proprietary period.
"Even I've tried to get more data," Mr Dordain said. "I might be the DG but I'm also a fan of Rosetta and [its lander] Philae. It's a problem; I don't deny it's a problem. But it's a very difficult problem, too," he told BBC News.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
Philae, the first robot to land on a comet, has reached the end of its life and is bidding a final farewell to Earth through a series of sad tweets.
"It's time for me to say goodbye," Philae tweeted on Tuesday. "Tomorrow, the unit on @ESA_Rosetta for communication with me will be switched off forever..."
SpaceAholic Member
Posts: 4676 From: Sierra Vista, Arizona Registered: Nov 1999
posted 09-01-2016 12:06 PM
Report in Nature on analysis of 67P captured dust particles.
Here we report in situ measurements of dust particles at comet 67P/Churyumov-Gerasimenko.
The particles are aggregates of smaller, elongated grains, with structures at distinct sizes indicating hierarchical aggregation. Topographic images of selected dust particles with sizes of one micrometre to a few tens of micrometres show a variety of morphologies, including compact single grains and large porous aggregate particles, similar to chondritic porous interplanetary dust particles.
The measured grain elongations are similar to the value inferred for interstellar dust and support the idea that such grains could represent a fraction of the building blocks of comets.
Headshot Member
Posts: 950 From: Vancouver, WA, USA Registered: Feb 2012
posted 09-25-2016 11:05 AM
Rosetta will essentially free-fall slowly towards the comet in order to maximise the number of scientific measurements that can be collected and returned to Earth before its impact.
Has ESA estimated what Rosetta's velocity at impact will be?
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
One of the key features of the trajectory design is to minimise the spacecraft's relative velocity at impact. The current scenario predicts that the impact velocity will be around 90 cm/s, around walking pace. It is worth keeping in mind that Rosetta was not designed as a lander, and some of its appendages including the 32m-wide solar panels will be damaged by the impact. This energy dissipation will very likely ensure that the escape velocity will not be exceeded during any bounce, thus preventing Rosetta from returning to orbit after impact with Comet 67P/C-G.
If Rosetta does bounce back into space, would we know?
No, because Rosetta's main systems, including the main transmitter, will be turned off at the moment of impact.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 09-29-2016 11:13 PM
From ESA's Rosetta blog:
We've started to get images from Rosetta's descent. This one was taken by the OSIRIS narrow-angle camera at 01:20 UT, from a distance of around 16 km [10 miles].
The image scale is about 30 cm/pixel and the image measures about 614 m across.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 09-30-2016 04:06 AM
From ESA's Rosetta blog:
Rosetta's OSIRIS narrow-angle camera captured this image of Comet 67P/Churyumov-Gerasimenko at 05:25 GMT from an altitude of about 11.7 km during the spacecraft's final descent on 30 September.
The image scale is about 22 cm/pixel and the image measures about 450 m across.
Rosetta's OSIRIS narrow-angle camera captured this image of Comet 67P/Churyumov-Gerasimenko at 06:53 GMT from an altitude of about 8.9 km during the spacecraft's final descent on 30 September.
The image scale is about 17 cm/pixel and the image measures about 350 m across.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 09-30-2016 04:09 AM
ESA video
Rosetta revisits the exciting scientific discoveries she made during her time at Comet 67P/Churyumov-Gerasimenko, including the successful search to find Philae. Finally, she starts preparing to descend to the comet for the end of her extraordinary mission.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 09-30-2016 04:29 AM
From ESA's Rosetta blog:
Rosetta's OSIRIS narrow-angle camera captured this image of Comet 67P/Churyumov-Gerasimenko at 08:18 GMT from an altitude of about 5.8 km during the spacecraft's final descent on 30 September.
The image scale is about 11 cm/pixel and the image measures about 225 m across.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 09-30-2016 07:25 AM
From ESA's Rosetta blog:
Rosetta's OSIRIS narrow-angle camera captured this image of Comet 67P/Churyumov-Gerasimenko at 10:14 GMT from an altitude of about 1.2 km during the spacecraft's final descent on 30 September.
The image scale is about 2.3 cm/pixel and the image measures about 33 m across.
Rosetta's last image of Comet 67P/Churyumov-Gerasimenko, taken shortly before impact, at an altitude of 20 m above the surface.
The image was taken with the OSIRIS wide-angle camera on 30 September. The image scale is about 5 mm/pixel and the image measures about 2.4 m across.
One Big Monkey Member
Posts: 173 From: West Yorkshire, UK Registered: Jul 2012
posted 09-30-2016 02:04 PM
Farewell Rosetta, and we thank you.
chris_petty Member
Posts: 14 From: Registered: Nov 2015
posted 10-13-2016 04:50 AM
Following the conclusion of the Rosetta Mission, I've been taking a look at the story behind the animated characters we all became so familiar with.
It's often easy to concentrate on the "nuts & bolts" of missions and forget about the importance of outreach and communication to the general public. I think ESA has done a really great job on this, so it was interesting to dig into the subject and find out more about their approach.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 10-15-2016 02:46 PM
From Anatoly Zak (RussianSpaceWeb.com) on Twitter:
Soviet-Ukrainian astronomer Klim Churyumov, who discovered comet 67P and got to see it explored by the Rosetta spacecraft, dies in Kiev.
(This isn't a memorial thread, so no "." moments of silence, but replies are still welcome.)
SpaceAholic Member
Posts: 4676 From: Sierra Vista, Arizona Registered: Nov 1999
Amongst the many features observed by Rosetta on the nucleus of the comet, one peculiar fracture, 70 m long and 1 m wide, was identified on images obtained in September 2014 at the edge of a cliff named Aswan9. On 10 July 2015, the Rosetta Navigation Camera captured a large plume of dust that could be traced back to an area encompassing the Aswan escarpment. Five days later, the OSIRIS camera observed a fresh, sharp and bright edge on the Aswan cliff. Here we report the first unambiguous link between an outburst and a cliff collapse on a comet.
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 10-27-2020 06:31 PM
From the long-dormant Philae lander on Twitter:
There is something I would like to tell you... tomorrow at 17:00 CET.
That is 12 p.m. EDT on Wednesday, Oct. 28 (2020).
Robert Pearlman Editor
Posts: 44912 From: Houston, TX Registered: Nov 1999
posted 10-28-2020 11:26 AM
From the Philae Lander (via Twitter):
My second touchdown on Comet 67P made a great new discovery possible: a mixture of ice and dust fluffier than the froth on a cappuccino. Mmm... read all about it.
posted 11-15-2014 01:36 PM
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