IPB

Welcome Guest ( Log In | Register )

95 Pages V   1 2 3 > »   
Reply to this topicStart new topic
Philae landing on the nucleus of Comet 67P C-G
vikingmars
post Sep 23 2014, 12:16 PM
Post #1


Senior Member
****

Group: Members
Posts: 1073
Joined: 19-February 05
From: Close to Meudon Observatory in France
Member No.: 172



Attached Image


Now, it's time to open a new section devoted to the landing of the Philae lander itself on the nucleus of Comet 67P C-G.

Also to answer better the earlier post,
http://www.unmannedspaceflight.com/index.p...st&p=212943
and for your information, here is the quick summary (as a "pdf" file) of the events that are expected to occur during landing on the nucleus and after : it's the timeschedule on which we are working to set up our EPO event in Paris.
Attached File  Sequence_ATTERRISSAGE10_UMSF.pdf ( 263.81K ) Number of downloads: 4502

The landing itself should occur around November 11th.

We'll keep you informed smile.gif
Go to the top of the page
 
+Quote Post
SpaceScout
post Sep 23 2014, 02:14 PM
Post #2


Junior Member
**

Group: Members
Posts: 31
Joined: 3-August 14
From: Germany
Member No.: 7229



Great information, thank you!!
ROLIS will take nadir images all the way down from the separation to landing and I am sure the images will be of high scientific values, but as I am reading in the document, the images will be uplinked to Rosetta only after touchdown. Was there no way to transmit the images as quickly as possible, without waiting for the landing?


--------------------
space scout
Go to the top of the page
 
+Quote Post
Phil Stooke
post Sep 23 2014, 02:41 PM
Post #3


Solar System Cartographer
****

Group: Members
Posts: 10122
Joined: 5-April 05
From: Canada
Member No.: 227



The idea of transmitting images during the descent has been considered before, even as far back as the Surveyor landings on the Moon, and including Phoenix on Mars (actually, Phoenix MARDI images were not to be transmitted live, just transferred into the flight computer, and even that was too much of a risk).
Every time it has been abandoned because of the number and complexity of other operations at the same time.

Phil


--------------------
... because the Solar System ain't gonna map itself.

Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
Go to the top of the page
 
+Quote Post
vikingmars
post Sep 23 2014, 03:40 PM
Post #4


Senior Member
****

Group: Members
Posts: 1073
Joined: 19-February 05
From: Close to Meudon Observatory in France
Member No.: 172



QUOTE (SpaceScout @ Sep 23 2014, 04:14 PM) *
Great information, thank you!!
ROLIS will take nadir images all the way down from the separation to landing and I am sure the images will be of high scientific values, but as I am reading in the document, the images will be uplinked to Rosetta only after touchdown. Was there no way to transmit the images as quickly as possible, without waiting for the landing?

Dear SpaceScout, thank you for your kind comments.
Considering the great involvement of Germany in this mission, I should have put the timeschedule in German also, but my writing with Goethe's style is somewhat shaky : all my apologizes !
Yes, Phil is right : ESA does not want to interefere through the instructions with the transmitting of data during the landing phase. Sorry : so we will have to wait for the ROLIS images after a safe landing on the nucleus.
Go to the top of the page
 
+Quote Post
Phil Stooke
post Sep 23 2014, 04:44 PM
Post #5


Solar System Cartographer
****

Group: Members
Posts: 10122
Joined: 5-April 05
From: Canada
Member No.: 227



I just realized that I forgot about Chang'E 3 in my comments above. We did have spectacular video of the descent and landing. But I realized - I don't know if that was transmitted during or after landing.

Phil


--------------------
... because the Solar System ain't gonna map itself.

Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
Go to the top of the page
 
+Quote Post
Explorer1
post Sep 23 2014, 05:51 PM
Post #6


Senior Member
****

Group: Members
Posts: 2073
Joined: 13-February 10
From: Ontario
Member No.: 5221



I think it was halfway; I recall the streamed images were received at a much lower rate then the final landing movie; either only some were released on the live stream or only some were transmitted during the sequence.
Ok, found it:
Here is the live stream recording:
https://www.youtube.com/watch?v=jyg56VIKRNA
And the 'complete' video:
https://www.youtube.com/watch?v=XNAGFTRvgDY

To not derail too far; what will be sent from Philae during the descent if not images; there will be some telemetry?
Go to the top of the page
 
+Quote Post
SpaceScout
post Sep 23 2014, 06:00 PM
Post #7


Junior Member
**

Group: Members
Posts: 31
Joined: 3-August 14
From: Germany
Member No.: 7229



QUOTE (Phil Stooke @ Sep 23 2014, 04:41 PM) *
Every time it has been abandoned because of the number and complexity of other operations at the same time.

If I am getting this right, is the high number of processes that the computer needs to handle during descent (although is free fall) that prevent transmitting images ? Will Philae transmit live any telemetry at all to Rosetta before touchdown?
I am just thinking about the improvements that could be made for a next generation landing probe... rolleyes.gif


--------------------
space scout
Go to the top of the page
 
+Quote Post
MarsInMyLifetime
post Sep 23 2014, 06:15 PM
Post #8


Member
***

Group: Members
Posts: 148
Joined: 9-August 11
From: Mason, TX
Member No.: 6108



QUOTE (SpaceScout @ Sep 23 2014, 12:00 PM) *
If I am getting this right, is the high number of processes that the computer needs to handle during descent (although is free fall) that prevent transmitting images ? Will Philae transmit live any telemetry at all to Rosetta before touchdown?
I am just thinking about the improvements that could be made for a next generation landing probe... rolleyes.gif

This is an interesting paper on the original conceptual design of Philae--from 1997! (just to remind ourselves of the era for which available stable technologies were being considered, and what incredible now-stable things might be in a next-gen lander)

http://www.open.ac.uk/personalpages/a.j.ba...ine/capcom.html

No descent imaging was even described in that paper, so the present capability and operational plan is a privilege, considering. Whole careers go by in the course of one such mission!


--------------------
--
Don
Go to the top of the page
 
+Quote Post
djellison
post Sep 23 2014, 06:47 PM
Post #9


Founder
****

Group: Chairman
Posts: 14431
Joined: 8-February 04
Member No.: 1



I don't believe they'll be taking a lot of descent images....indeed, there's not much point. OSIRIS resolution will out-perform that of the descent imaging until we're pretty close to the surface. One before bettering OSIRIS res , one at some intermediate point, one just before touch-down.....that would be enough for a very good localization.
Go to the top of the page
 
+Quote Post
vikingmars
post Sep 23 2014, 08:29 PM
Post #10


Senior Member
****

Group: Members
Posts: 1073
Joined: 19-February 05
From: Close to Meudon Observatory in France
Member No.: 172



QUOTE (djellison @ Sep 23 2014, 08:47 PM) *
I don't believe they'll be taking a lot of descent images....indeed, there's not much point. OSIRIS resolution will out-perform that of the descent imaging until we're pretty close to the surface .../...

Yes, Doug : indeed ! OSIRIS has a far better resolution than ROLIS from orbit.
This is why ROLIS will take just a few images during the descent. BUT at a low altitude (i.e. tens of meters from the surface) and until touchdown, it will start taking one image every 5 seconds...
Go to the top of the page
 
+Quote Post
machi
post Sep 23 2014, 10:04 PM
Post #11


Member
***

Group: Members
Posts: 796
Joined: 27-February 08
From: Heart of Europe
Member No.: 4057



Original plan was (and it looks still is) to take few images after release from Rosetta and then few images before landing.
"Few" means up to 8 images.



--------------------
Go to the top of the page
 
+Quote Post
Tom Tamlyn
post Sep 24 2014, 03:21 AM
Post #12


Member
***

Group: Members
Posts: 443
Joined: 1-July 05
From: New York City
Member No.: 424



QUOTE (Phil Stooke @ Sep 23 2014, 10:41 AM) *
The idea of transmitting images during the descent has been considered before, even as far back as the Surveyor landings on the Moon, and including Phoenix on Mars (actually, Phoenix MARDI images were not to be transmitted live, just transferred into the flight computer, and even that was too much of a risk).
Every time it has been abandoned because of the number and complexity of other operations at the same time.

Phil


The Ranger moon spacecraft perforce transmitted images during descent, because there wasn't any afterwards, but I can't think of any others. Well, maybe NEAR, if you call the whole approach a descent because the spacecraft eventually touched down, but that would be whimsical.

Can't think of any others, but of course I don't have the encyclopaedic recall of the two Dougs.

Go to the top of the page
 
+Quote Post
Hungry4info
post Sep 24 2014, 03:42 AM
Post #13


Senior Member
****

Group: Members
Posts: 1413
Joined: 26-July 08
Member No.: 4270



MSL did a whole descent movie. MER did a couple descent images if I recall right.
Edit: Nevermind. The discussion was about transmitting them during descent rather than storing and transmission later.


--------------------
-- Hungry4info (Sirius_Alpha)
Go to the top of the page
 
+Quote Post
Explorer1
post Sep 24 2014, 03:47 AM
Post #14


Senior Member
****

Group: Members
Posts: 2073
Joined: 13-February 10
From: Ontario
Member No.: 5221



And don't forget Huygens!
It's true that discussing why Huygens transmitted pictures on the way down and Philae won't is comparing apples and oranges (one had atmospheric observations as the primary objective with landing as a bonus, while the other is exclusively a lander), but there is a precedent of descent imaging from ESA.
Go to the top of the page
 
+Quote Post
Hungry4info
post Sep 24 2014, 03:51 AM
Post #15


Senior Member
****

Group: Members
Posts: 1413
Joined: 26-July 08
Member No.: 4270



QUOTE (Explorer1 @ Sep 23 2014, 10:47 PM) *
...there is a precedent of descent imaging from ESA.

Was there anything similar planned for Beagle 2?


--------------------
-- Hungry4info (Sirius_Alpha)
Go to the top of the page
 
+Quote Post

95 Pages V   1 2 3 > » 
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 19th March 2024 - 04:48 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.