На ски в Андора

И тази година, както и предишната 2008, решихме да ходим на ски в Андора, в Солдеу (Soldeu) по Коледа - от 20 до 26 декември. Шест нощувки на хотел и пет дни ски. В хотел Галантус (Galanthus) както и 2008.

Не уцелихме хубаво време, както се вижда на прогнозите: сняг, дъжд, вятър.
 
За късмет синоптиците не бяха познали за петък (25 декември)  - беше слънчево и много хубаво време. Но като цяло си беше много лошо време - за пръв път карах ски в проливен дъжд с вятър. С Милена издържахме само едно-две спускания и трябваше да се прибираме в хотела, защото се измокрихме до кости, а и снега не беше никак добър за каране: тежък и мокър. Не сме чак такива екстремисти, че да се подлагаме на такива мизерии :-)

Third day of SPIRE, SMEC LVDT in close loop

This test command the SMEC to perform a number of scans by itself, back and forth.This is the picture with “M”-like figure showing two scans as expected.

The excitement of the team is quite obvious.

Second day of SPIRE, unlatch the spectrometer mechanism

The Spectrometer mechanism (SMEC) is a moving part, which is used to change the optical path difference (OPD) by scanning back and forth and produce an interferogram of the signal as a function of this OPD. The inverse Fourier transform of the interferogram is the source spectrum.
During the launch the SMEC was latched in order to avoid breaking or damaging the instrument. The unlatching is very critical moment as in space all mechanical movements can be unpredictable, especially after a powerful launch with a rocket.

The snapshot shows the movement of the SMEC after the unlatch procedure has been executed. This is exactly what is expected for a successful unlatch! And there are no traces of any stickiness which was observed during some of the ground based tests.
All data confirm that the SMEC moves in zero gravity.

First day of SPIRE, switch on the Spectrometer

After we switched on successfully the Photometer we proceeded further to switch on the Spectrometer. Initially it was planned to switch only half of one of the spectrometer arrays, because the other half showed problems during ground tests, especially at low temperatures of the optical bench. But in day 6 the optical bench was at acceptable temperature and that is way it was decided that we switch on the whole bolometer array.

The half of the array that was problematic showed the same behaviour: it switched on first but then it switched off. We had to increase the voltage line feeding the JFETs in order to switch it on. The drawback of this is that the bolometers will be operating at non optimal conditions and the noise will be higher.

Fortunately, at the end of the test, when we switch back to low voltage the JFETs kept working and the noise properties were looking the same. We still have to see this when the instrument is at the nominal in flight conditions, which will be after few weeks.

First day of SPIRE, switch on the Photometer

The Photometer was successfully switched on: all detectors changed from black to orange, except those which were known from ground tests not to be active (they turned white). The detectors (bolometers) are too warm, they are at 1.9-2.0 K and in this condition they act as resistors. For their normal function they need to be at 300 mK, which will be possible after the cooler is recycled and the evaporation of He3 starts (planned for day 8).

This is how we look at the signals from the instrument. The tool is called QLA (from quick look analysis) and it connects to a real time telemetry database. The telemetry coming from the satellite during the daily telecommunication periods.

SPIRE switch-on

After the successful launch of Herschel and Planck satellites with Ariane-5 on 14 May 2009, and after few days of Low Earth Orbit Phase (LEOP), the commissioning of the Herschel telescope started. Initially the instruments were planned to be switched on starting on day 9 (22 May 2009) but were put forward by 3 days.

SPIRE was the first instrument to go on day 6, followed by the other two instruments HIFI and PACS on day 11.

May 19th, 2009 (OD06, day of year 139) 11:34:54 UTC, the day we switched on SPIRE, one of the detectors on board Herschel Observatory. This is the moment when the command was sent to the spacecraft and executed with success. A great moment for the whole mission.
The command sent by the operator to the spacecraft: SwOn_Spire_HSPDU_N_L11 at 2009.139.11.34.56.493 executed with status all green!




The SPIRE team running the switch on and the manual commanding:

From left to right:
Anthony Marston (HIFI person) is the group leader of the Instrument and Calibration Scientists at the Herschel Science Centre, ESA.
Tanya Lim, SPIRE ICC manager. She is the QLA operator.
Matt Griffin, SPIRE PI. He supervises the activities.
Markos Trichas, SPIRE ICC worker. He keeps the log of what is being done.
Bruce Swinyard, SPIRE co-PI. He also supervises the activities as well as the first real time data analysis.
Sunil Sidher, SPIRE Instrument Scientist. He is the one who interacts with the MOC operator and commands the whole parade.
Ken King, SPIRE ICC. He is checking the real time telemetry packets.