Philae

[mars76]

Zgadzam się z tym argumentem; chociaż takie lądowanie jednak dla publiczności jest głównym show ; podobnie jak było z cassinim i europejskim lądownikiem ( większość ludzi oczekiwała udanego lądowania i pierwszych zdjęć z opadania i powierzchni tytana )

[Air Q]

Rozpiska wydarzeń, która przyda się w środę:
http://blogs.esa.int/rosetta/2014/11/07/rosetta-and-philae-landing-timeline/

[mars76]

Dzisiaj w National Geografic Channel HD o godz 22  jest premiera filmu dokumentalnego produkcji angielskiej z 2014 roku o lądowaniu na komecie i misji Rosetty ; z reklam będą niezłe efekty wizualne- więc warto polecić:))!!!

[Scorus]

Plan przebiegu pierwszej sekwencji naukowej. Brakuje jednak informacji co konkretnie poszczególne instrumenty będą robić, np które sensory MUPUS i SESAME będą używane. Jak widać zdjęć nie będzie dużo.

http://blogs.esa.int/rosetta/2014/11/10/philaes-first-science-sequence-timeline/

[JSz]

Planowane miejsce lądowania Philae, określane dotąd jako "J", otrzymało nazwę: "Agilkia". Nazwa ta pochodzi od wyspy na Nilu, na której znajdują się słynne starożytne budowle. Wyłoniono ją w wyniku konkursu, w którego jury zasiedli przedstawiciele ESA i agencji kosmicznych kilku krajów.

Webcast (z przerwami) rozpocznie się już dzisiaj:

Webcast live from mission control: http://new.livestream.com/esa/cometlanding
Webcast will begin 19:00 GMT (20:00 CET) 11 November and continue (with pauses) to cover crucial mission milestones overnight on Tuesday and through Wednesday. Check the ESA TV schedule here for detailed times.

Źródło: http://www.esa.int/Our_Activities/Operations/Live_updates_Rosetta_mission_comet_landing

Ponadto można śledzić ćwierknięcia:
http://www.twitter.com/ESA_Rosetta
http://www.twitter.com/philae2014

Njaświeższa animacja lądowania:

[Matias]

Dzisiaj w National Geografic Channel HD o godz 22  jest premiera filmu dokumentalnego produkcji angielskiej z 2014 roku o lądowaniu na komecie i misji Rosetty ; z reklam będą niezłe efekty wizualne- więc warto polecić:))!!!

Nagrałem i obejrzałem na razie 1/3 - wygląda i brzmi świetnie Rozmawiałem jednak z Maquisem, który mi powiedział, że zapomnieli w tym materiale na końcu wspomnieć o MUPUSie

Nie wiem czy wybyło, ale zapodaję - fajna grafika przedstawiająca fazy misji / lądowania, grafiki porównawcze (skala), itd.

[mars76]

Dzisiaj w National Geografic Channel HD o godz 22  jest premiera filmu dokumentalnego produkcji angielskiej z 2014 roku o lądowaniu na komecie i misji Rosetty ; z reklam będą niezłe efekty wizualne- więc warto polecić:))!!!

Nagrałem i obejrzałem na razie 1/3 - wygląda i brzmi świetnie Rozmawiałem jednak z Maquisem, który mi powiedział, że zapomnieli w tym materiale na końcu wspomnieć o MUPUSie

Nie wiem czy wybyło, ale zapodaję - fajna grafika przedstawiająca fazy misji / lądowania, grafiki porównawcze (skala), itd.

Świetna grafika szkoda tylko ze przy powiększeniu się nie wyostrza:(

[Matias]

Dzisiaj w National Geografic Channel HD o godz 22  jest premiera filmu dokumentalnego produkcji angielskiej z 2014 roku o lądowaniu na komecie i misji Rosetty ; z reklam będą niezłe efekty wizualne- więc warto polecić:))!!!

Nagrałem i obejrzałem na razie 1/3 - wygląda i brzmi świetnie Rozmawiałem jednak z Maquisem, który mi powiedział, że zapomnieli w tym materiale na końcu wspomnieć o MUPUSie

Nie wiem czy wybyło, ale zapodaję - fajna grafika przedstawiająca fazy misji / lądowania, grafiki porównawcze (skala), itd.

Świetna grafika szkoda tylko ze przy powiększeniu się nie wyostrza:(

U mnie wszystko bardzo przejrzyście, nie w pełni Ci się otwiera chyba.

Tymczasem wpis z Kosmonauty odnośnie statusu Philae z porannej konferencji (za 20 minut następna!):
"Andrea Accomazzo, dyrektor operacji misji Rosetta, wspomniał, że lądownik Philae nie uruchomił się poprawnie, tak jak planowano. Wykonanie restartu jego systemu umożliwiło jednak w pełni pomyślne uruchomienie. Sytuacja obrazowo porównana została do poranka, w czasie którego pierwszy alarm z budzika lub telefonu nie budzi nas w pełni ze snu. Lądownik Philae jest obecnie w dobrym stanie. Za kilka godzin rozpocznie się jego "rozgrzewanie" przed jutrzejszym oddzieleniem od sondy Rosetta."

Z ekipy Kosmonauty na miejsce jadą już Velo i NH2501 - mam nadzieję, że nie będą zalewać operatorów misji trudnymi pytaniami, bo ci mają obecnie jedną z najbardziej wyczerpujących dób w swoim życiu!

[Matias]

Emilly Lakdawella, jedna z najsłynniejszych blogerek w astro-światku, zebrała tweety naukowców z wczorajszej, "zamkniętej" konferencji naukowców odnośnie najnowszych wyników badań komety 67P. Żadne zdjęcia nie wyciekły do Internetów (dziwne!!!), ale podobno wywołują opad koparek szczękowych! Jeśli dobrze kojarzę fakty, to jutro powinno być trochę "publikacji" tych materiałów graficznych.

http://www.planetary.org/blogs/emily-lakdawalla/2014/11110059-report-from-darmstadt.html

[Matias]

Z powyższego wpisu Emilli ciekawy tweet:

Andrew Steffl @plasma_torus
Follow
Hofstadter MIRO sees "porous, dusty surface that is incredibly insulating"You only need to go down a mm or 2 to go down 50K in temp #DPS2014

Wow!

[Scorus]

Problem przy uruchamianiu był prawdopodobnie wywołany przez niską temperaturę.

Ciekawe, że lądownik musi ładować baterie przez kilka dni między sekwencjami naukowymi, co powiedzieli na briefingu:
http://blogs.esa.int/rosetta/2014/11/11/media-briefing-10-nov-replay/

Dane z magnetometru ROMAP pozwolą na wykrycie takich czynności jak rozkładanie podpór lądownika, będąc niezależnym źródłem informacji podczas rekonstruowania przebiegu lądowania.
http://blogs.esa.int/rosetta/2014/11/11/tracking-philaes-descent-with-magnetic-data/

[Scorus]

O przebiegu lądowania:

10 November, 2014

Philae is a so-called passive lander. This means it does not have a navigational and thruster system on board that can be used to guide it actively to the desired landing site. Or to put it in somewhat simple words: Philae is thrown down by the orbiter to the surface, however, with the aim to reach a predefined landing site on the comet. It is a bit like throwing a dart to the red center of a dart board. However, Philae has some additional requirements a dart player usually does not have to follow: it has to be thrown from a moving orbiter, with predefined speed such that it will land in a vertical orientation at a speed of about 1m/s or less at the targeted landing site. The Rosetta orbiter is the dart player running orbiting around the comet. The release velocity of the lander is fixed by hardware and commanding to 19 cm/s and the range of the touch-down speed and the trajectory orientation are fixed as well. So, the orbiter has to fly a very specific orbit for the lander release and the release itself has to happen at a well-defined point in time and space and with a well-defined orientation. This is indeed a very delicate task for the orbiter to perform and requires a special preparation phase on the spacecraft side.
 
Before release, the fly wheel of the lander is switched on since it is needed during the whole descent in order to keep the orientation of the main body axis of the lander constant in space. During the descent until touch-down the orientation of the main body axis of the lander is meant to be perpendicular to the surface of the nominal landing point. Slight rotation of Philae around this axis may happen during descent.

When the release point is reached, the lander will be ejected from the orbiter. The lander separation works through a spindle drive system. In case the spindle mechanism is not performing as expected, a spring eject mechanism will be used. Both mechanisms will be activated automatically within less than 30 sec such that Philae will escape from the orbiter within the right time window at a speed of 19 cm/s. However, first a so-called wax actuator has to to be opened since it holds the whole lander attached to the orbiter. In order not to release the lander too early after being freed via the wax actuator, the spindle drive is run in pull mode to press the lander softly against the orbiter interface until release time. The release also pulls off the umbilical cable between orbiter and lander which is used for power, command and data exchange between both spacecraft. Already some time before the release, the lander runs on internal battery power and all necessary 'life' systems are up and running. The separation phase will be a very critical time period for the MPS engineers since it is they who are responsible for the proper functioning of the lander release hardware.

Before release, the parts of the CONSERT instrument on the orbiter and on the lander will have already communicated with each other and are meant to keep contact for almost the whole 7 hours long descent period until shortly before touch-down. CONSERT intends to collect science data during descent that will be also useful to determine the separation distance of the two spacecraft and thus the descent orbit of the lander.

Very shortly after lander separation, the orbiter will slew in space and perform escape maneuvers from the release orbit, however, in such way that it can keep radio link contact with the descending lander. Philae separates further from the orbiter, and in a safe distance the landing gear is released from its storage position which it had over the long time period of the journey to 67P. This means unfolding the landing legs and 'lifting' the touch-down drive to maximum capacity. It will be initiated by so called 'hot knifes' that are heated and 'cut' through the fixation of the preloaded unfolding mechanism. Moreover, also the CONSERT antenna will unfold and the ROMAP arm will be put in optimum measurement position.

Two hours after release, lander and orbiter spacecraft are ready to start a continuous data and command link again which got interrupted due to the special orientation and maneuvering of the orbiter for the lander release. As of this time the ground control team should be able to follow closely how the lander performs during its descent to the surface – of course with a delay of about half an hour for the signal travel time from the comet to Earth. Before that time, only the CONSERT instrument signal will tell indirectly that the lander is 'alive'.

The next four hours will see lander descent operations together with some scientific measurements performed by CONSERT, ROLIS, and ROMAP (see earlier blog entry) as well as calibration measurements by MUPUS and SESAME. The latter are only possible to be collected during descent since it requires open view to dark empty space for MUPUS and the exact geometry of the unfolded landing tripod for SESAME.

During the last hour of the descent, the lander prepares for the landing. First of all, Philae needs to be able to sense the touch-down on the surface. This is done via detection of a sudden deceleration of the lander motion, not an easy task and in fact the touch-down trigger is expected to come from a motion of the landing gear motor – now operated as a current generator - when it is pushed back into the lander body as soon as the landing tripod gets surface contact. The lander carries also two accelerometers that were installed for exactly the task to sense the touch-down at the surface. However, these devices cannot be switched on, since the fly wheel of the lander 'makes so much noise' that the accelerometers would trigger the touch-down sequence (see below) already during descent and long before the surface is reached. This is bad luck and was certainly not intended, but it became only noticeable during the cruise phase of the Rosetta mission, and after analysis it was clear that nothing can be done about it apart from disabling the accelerometers from their function during descent.

Very likely surface contact will be first by one foot of the landing tripod, then a second one and then the third one. The surface contacts of the tripod will also drill the ice screws of the landing feet (one per foot) into the ground. These screws act like a drill, driven by pure mechanical energy from the touch-down motion of the lander. They help fix the lander to the ground and also prevent lateral motion of the lander during touch-down.

Due to the inertia of motion the body of the lander will move further towards the surface while the landing tripod has already stopped. As a consequence, the landing gear motor is moved further and this way motion energy of the lander is extracted and transferred into electrical energy. Through this process is will be possible to absorb most of the kinetic energy of the descent motion during the touch-down of the surface (btw, the electric energy produced by the landing gear motor will be turned into thermal energy and then conducted and radiated to the cometary nucleus and into space).

The touch-down signal by the landing gear triggers the anchoring of the lander. Anchoring is needed since the cometary gravity is so weak that the lander might otherwise bounce back into space. Moreover, any future surface operation like for instance drilling for subsurface samples would uplift the lander from the surface. So, the anchoring process starts with the 'firing' of the active descent system, a thruster that is embedded in the top surface of the lander body. This thrust pushes the lander against the surface. After a few seconds the two harpoons are ignited and shot into the ground. After they have stopped, the anchoring ropes which are connected to the harpoon heads are pulled back such that the lander spacecraft is tightened to the surface. The thruster firing has to continue well beyond the anchor shooting since the latter pushes the lander back from the surface due to the reaction force from the explosion of the harpoon firing. After less than a minute the anchoring process is finished and Philae has safely landed on comet 67P/Churyumov-Gerasimenko. The touch-down and anchoring period of the lander again will be an exciting moment for the MPS engineers in the control room since they are responsible for the proper functioning and operations of the landing gear and anchoring harpoons.

The last phase before and during touch-down sees scientific activities of some lander instruments, i.e. ROLIS imaging the surface granularity from a few meters distance until touch-down, ROMAP trying to measure local magnetic fields, MUPUS measuring the deceleration of the harpoons while they penetrate into the cometary ground and SESAME determining mechanical properties of the surface soil while the lander feet touch the ground. Immediately after landing CIVA will take first panorama images of the landscape of the landing site. They will be used together with ROLIS descent images of the landing site and terrain models obtained from the OSIRIS and NAVCAM images onboard of the orbiter to identify the landing location and its exact coordinates on the nucleus. Moreover, and also supplemented by ROMAP science measurements and voltage measurements of the solar arrays, also the lander orientation will be derived. This requires, however, that the respective instrument and housekeeping data are quickly uplinked from the lander to the orbiter and from there to Earth. Immediately thereafter the first automated instrument sequences of the First Science Sequence at the cometary surface are started.

All what is described in this blog section is performed through predefined command sequences prepared by the lander operations team and uplinked and stored in the onboard computer for execution. Due to the long delay of command and data signals between lander and Earth everything is done automatically and without intended interaction from the control center. The engineers and scientist can and will follow the sequence of events performed by the two spacecraft, the Rosetta orbiter and the Philae lander, during the period of separation, descent and landing remotely, and certainly with great excitement.

Despite of the very careful preparation and testing of all the command sequences and the tedious selection of the landing site on the cometary surface, a successful Philae landing requires still a good piece of luck and is not for granted. Regardless how it will all work out, I am sure those who can participate closely in the control rooms or close by – and maybe even people watching the landing remotely – will never forget the landing day of the Philae spacecraft on comet 67P.

[Limax7]

trwa transmisja LIVE na:
http://new.livestream.com/ESA/cometlanding

i

http://www.esa.int/spaceinvideos/ESA_Live

[Scorus]

Po określeniu parametrów orbity jest zgoda na kontynuowanie procedury SDL (GO/NOGO1).
http://blogs.esa.int/rosetta/2014/11/11/gonogo-1-rosetta-is-on-track/

[Matias]

Trwa rozgrzewanie baterii lądownika.

Kolejne GO/NO GO dzisiaj o pierwszej w nocy, kto wytrwa do tego momentu? Historycznego momentu, więc pewnie trochę nas tu będzie!

Nasze chłopaki z Kosmonauty dotarli już do Darmstadtu i mam nadzieję ich niebawem ujrzeć w tym press roomie: https://twitter.com/elakdawalla/status/532254189230256128