Monday, March 10, 2008

HERSCHEL MISSION > Commander's Log Entry JD 2454531.47916

Leo Metcalfe, Herschel’s Science Operations Manager, shares with spacEurope's readers, in the second log entry (you may read the first one here) his impressions from the mission's latest developments now that seven months separate us from its launch to take place in October 2008.
Dear blogging commander, what's up?

HSCOM Log Second entry JD 2454531.47916

In the period since my previous entry the Herschel Science Operations Team (HOT)(*) at ESAC has continued to grow towards its Operational strength (around 45 people), with four new engineers or scientists joining in the period and some others making the transfer from ESTEC in the Netherlands to ESAC here in Spain.

The team look like a fairly happy bunch in the attached photo taken at ESAC in front of a model of ESA's earlier Infrared Space Observatory mission (ISO).

(*) I was thinking we could call this Blog "HOT people on a Cold Mission" !! ;))

A major milestone has been the adding to the mission database of the observation details for the 21 successful Open Time Key observing Programmes, joining the observation details from the 21 Guaranteed Time Key observing Programmes.

Open Time programmes are those that have been awarded observing time through competitive peer review of a much larger number of proposals submitted by astronomers in the worldwide astronomical community. Guaranteed Time programmes are programmes defined by the consortiathat built the scientific instruments, and constitute their return on investment.

So by now we know the targets for about half of the Herschel observing time. The rest of the time will be distributed later through competitive open Calls-for-Proposals pitched to the astronomical community.Intensive effort continues to go into the testing of the spacecraft in the facilities at ESTEC in the Netherlands. Some members of the Operations Team, myself included, had the chance at a recent ESTEC meeting, to see the spacecraft and the telescope in the clean rooms, where they are under test and awaiting integration.

I can't help remarking that the telescope mirror looks like a giant automobile headlamp reflector!

I'd be suspicious except the World's biggest truck doesn't appear to have much in the way of headlamps!
I'm going to get myself into trouble :)

Right at the moment the spacecraft is reaching thermal equilibrium after the Helium cryostat has been filled with hundreds of litres of Liquid Helium at just a few degrees above the absolute zero oftemperature. The consequent cooling of the infrared detectors is essential to their ability to detect the far-infrared heat emission of the coldest sources in the Universe. We used to say that our earlier infrared mission, ISO, could detect an ice cube by its heat emission at a distance of 1000 km.

I haven't done the calculation yet for Herschel - I add it to the list of things to do, but it will be even more impressive!

The main focus now of the Operations Team is to arrive at launch fully adapted to working with the real spacecraft, and apart from the staff readiness, to have prepared and tested well in advance of launch a full representative set of Commissioning and Verification Phase calibration and test observations and measurements.

One crucial aspect of any operational mission is that great caution has to be exercised in making any changes to the system once it has entered Operations. To speak precisely, the system "configuration" has to be strictly controlled. So part of the preparations for Operations at this point is startup of the activities of the Operational Configuration Control Board or CCB.

This is a meticulous control process and system at the core of every mission's operational activity.

Leo Metcalfe
Herschel Science Operations Manager (HSCOM)

Latest news on the Herschel mission status can be found here.

No comments: