10 July 2009, L+57d
All three Herschel instruments have now performed their initial first test observations.
SPIRE
HIFI
PACS
find more: http://herschel.esac.esa.int/latest_news.shtml
09 July 2009, L+56d
A collection of 'First Light' images and spectra taken by the three instruments onboard Herschel during the days following the cryo-cover opening will be publicly made available this Friday 10 July.
Tonight at 00UT Herschel will be 1.575 million kilometres from Earth and approaching at 11m/s.
The Herschel liquid helium tank is at 1.636K. The secondary mirror is at 81.1K and the primary at 84.1K.
More than 88% (250 out of 284Herschel ) commissioning activities have been executed.
Herschel is about magnitude V=19.5, although the latest amateur observations show quite a wide dispersion in magnitude.
01 July 2009, L+48d
Herschel's liquid helium tank is now at 1.645K. The primary mirror is at 88.1K and the secondary at 85.0K.
More than 77% (220 of 284) Herschel commissioning activities have been executed.
24 June 2009, L+41d
The focus on Herschel's activities will start to move slowly from commissioning check-out of systems) to Performance Verification.
The liquid helium tank is now at 1.657K and continues to cool slowly. The main telescope mirror is at 93K and the secondary at 90K.
As of yesterday, 208 of 284 Herschel Commissioning activities (73%) have been executed. Check-out phase is coming to an end.
23 June 2009, L+40d
The two Herschel mirrors have now cooled to 91.3K and 94.6K respectively. Their behaviour is as predicted.
Herschel's helium tank is now at a balmy 1.659K and still dropping. It is probably the best place in the Universe to chill-out!
Up to today, 68% (193 out of 284) Herschel commissioning activities have been completed.
19 June 2009, L+36d
First picture of PACS
http://www.esa.int/SPECIALS/Herschel/SEM76A0P0WF_0.html
http://herschel.esac.esa.int/latest_news.shtml
http://herschel.esac.esa.int/SneakPreview.shtml
http://www.dlr.de/desktopdefault.aspx/tabid-5105/8598_read-18016/
18 June 2009, L+35d
Planck will be 201600km from Herschel (0.525 Lunar Distances) and receding at 130m/s.
The telescope mirrors are now at 102K and 106K respectively. Today will be dedicated to HIFI performance characterisation and to SPIRE.
The liquid helium tank is at 1.681K today, still cooling nicely. The cooler that it gets, the longer the helium will last.
So far 174 out of 284 commissioning activities have been executed: that is 61% of the total.
17 June 2009, L+34d
The first images are to be formally released at Le Bourget on Friday the 19th.
Herschel's helium tank is still cooling as temperatures stabilise. It is at 1.687K.
The two telescope mirrors have reached 105K and 109K respectively. Estimates of how cold they will get are very uncertain. Thermal calculations are very difficult, but suggest a final temperature of the mirrors from 70-80K.
15 June 2009, L+32d
147 of 284 (52%) of Herschel commissioning activities have been executed. The helium tank has now cooled to 1.699K.
The latest SPIRE cryocooler hold time has been measured as 52 hours, beating the previous best of 47 hours. The cooler reached 287mK.
PACS reports (with a grin) that their final cooler hold time was a quite astonishing 70 hours! All instruments are reporting nominal status.
14 June 2009, L+31d
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The cryo-cover is open!!!!
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At about 10:45UT the command was given by the controllers to arm the two pyrotechnic devices on board. These were fired at 10:53:17UT.
The command was executed nominally, there is telemetry indicating that the cover reached the open position, the shaking of the spacecraft caused by the opening was seen on the gyros and the phase separator, and the temperatures at L0 and L1 slightly changed.
All of this is consistent with what you would expect from a successful cryocover opening!
10 June 2009, L+27d
How does the Herschel cryocover open? YOUTUBE has the answer!
http://www.youtube.com/watch?v=e2ggJuecb-8
Herschel is now 1.415 million kilometres from Earth and receding at 192m/s (691km/h). Signals take 4.5s to reach it.
Herschel carries the SREM (Space Radiation Environment Monitor) as a passenger, to measure constantly the radiation environment to which Herschel is exposed. Herschel Science Centre scientists analyse this data daily and are looking for possible correlations with solar activity and with predictions of future activity.
SREM shows that there has been no important activity registered in the data since Herschel crossed the Van Allen Radiation Belts. The variations in count rate can all be attributed to noise.
The peak count rate during the Van Allen Belt crossing was about 3 orders of magnitude greater than the count rate at any other point during the transfer orbit.
09 June 2009, L+26d
Yesterday at 11:06 UTC the large helium venting nozzle was closed by telecommand from ESOC. Successful closure was immediately confirmed by an increase of the temperatures of the phase separator, the level 1 and the external vent line as well as the pressure in the external vent line. The cryostat behaviour is nominal.
This was the last planned activity on the helium system, from now on the cryostat will be in passive control.
Opening of the cryo cover is planned for next Sunday, 14th June.
The mirror temperatures are now dropping steadily with the heaters off and the telescope in shadow.
Herschel is now about 5.5º south of the magnitude 5.7 star, 14 Ophiuchi.
05 June 2009, L+22d
PLANCK is now 87 600km from HERSCHEL and the two are separating at 80m/s. As seen from Herschel PLANCK has a magnitude of R=13.1.
03 June 2009, L+20d
At 00UT tonight Herschel will be 1.217 million kilometres from Earth and receding at 0.30km/s, effectively now at L2.
Mirror decontamination will stop on June 6th. From then on the mirrors will be allowed to cool to about 70K.
It was decided that the next orbit correction manoeuvre will take place on June 10th. This will be a tiny nudge of Herschel.
110 out of 284 commissioning tasks had been completed (39%). Yesterday PACS finished commissioning the diffraction grating.
The first SPIRE spectrum shows that SPIRE is looking good
02 June 2009, L+19d
Herschel is more than 1.190 million km from Earth and receding at 0.32km/s. Signals now take 4.0 seconds to reach the spacecraft.
Commissioning the PACS chopper has concluded well ahead of schedule.
First light of Herschel is planned for June 14th.
29 May 2009, L+15d
In total, 31% of the Herschel commissioning activities have been completed to date (89 out of 289).
28 May 2009, L+14d
Yesterday's first automatic cooler recycle for SPIRE worked extremely smoothly. A temperature of 290.1mK was reached!
Automatic cooler recycling is a fundamental part of operations and the fact that it worked perfectly is another great Herschel milestone.
The spacecraft is thus in an excellent condition and behaving better than anyone ever expected at this stage.
27 May 2009, L+13d
Herschel is now more than 990 000km from Earth and receding at 0.46km/s. Signals now take more than 3.3s to reach the satellite.
It is now 1.0195AU from the Sun. Herschel remains in Ophiuchus.
26 May 2009, L+12d
On 24 May, the third and final Herschel science instrument, HIFI, was successfully switched on. It has undergone a series of tests that show the functionality of its focal plane units -- the 4 spectrometers, its electronics units and the main moving component its chopper. All functional tests have been declared successful.
As HIFI is a heterodyne unit, it also requires the use of a local oscillator unit. HIFI has a sophisticated and complex local oscillator system that allows its spectrometers to obtain high-resolution spectra across a very wide range of frequencies. The local oscillator (LO) unit, with its 14 separate signal-carrying chains,was tested today (26 May at ~14:15 - 17:00 UT). All 14 LO channels are alive and show power levels at the detectors (mixers) consistent with previous on-ground measurements. No icing of the LO windows is apparent, as was considered a possibility from outgassing during launch, and no misalignment of the LO chains is apparent to within 1-2%.
The HIFI instrument is fully functional and will now start to be setup to work optimally for science operations.
24 May 2009, L+10d
PACS has successfully been switched-on and passed the SFT (Short Functional Tests). Results confirm that all mechanisms are moving, calibration sources are heated up and the sorption cooler is electrically functional. The spectrometer's photoconductor arrays were fully operated, signal in the blue array is nominal, for the red array the spacecraft temperature conditions were still a bit high.
22 May 2009, L+8d
The SPIRE helium-3 cooler recycling has been successfully performed. A temperature of 293 mK was reached, making SPIRE - at least temporarily for now - the coldest known object in outer space!
20 May 2009, L+6d
HERSCHEL is located around 617 287 km from the Earth, approximately 1.6 times farther than the Moon's average distance of 384 403 km. HERSCHEL and PLANCK were separated by 9917.35 km.
The telescope is cooling down fully in accordance with flight predictions to the decontamination temperature of 170K (-103°C). The cryostat is also cooling to its operational temperature and the critical helium phase separator is working perfectly.
The planned operations for the LEOP (Launch and Early Orbit Phase) have been completed successfully, and all time-critical procedures were completed on schedule or sooner than expected, including the SPIRE (Spectral and Photometric Imaging Receiver) launch lock release.
