Terahertz Astronomy on

the Herschel Space

Observatory

A. Benz (Astronomy, ETH)

W. Bächtold (LEFME, ETH)

A. Megej (LEFME)

R. Limacher (LEFME)

Ch. Monstein (Astronomy)

Zürich

Galaxy:Stars and MolecularClouds

Stars form in molecular clouds

10'000 º K

30 º K

H2, CO, H2O, CO2, NH3, ...and a little dust: silicate, graphite,...

Molecular lines at mm wavelength

Far infrared

continuum

emission

(ISO satellite,

ESA)

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L2Herschel

Herschel

Herschel Objectives

1. Investigate the creation of stars and their interaction

with the interstellar medium

2. Study the formation of galaxies in the early universe

and their subsequent evolution

3. Observe the chemical composition of the

atmospheres and surfaces of comets, planets and

moons

4. Examine the molecular chemistry of the universe

• Herschel is the first observatory-class mission at Terahertz frequencies

• First complete coverage of wavelengths between far-infrared and

submillimeter, 60 - 670 m

• Highest spectral (107) and spatial (8") resolution in Teraherz region

Eidgenössische Technische Hochschule ZürichSwiss Federal Institute of Technology, Zürich

Swiss Guaranteed Time

Water in Mars atmosphere 10%

(Prof. Dr. Nicolas Thomas, University of Berne)

Extragalactic observations of C + 16%

(Prof. Dr. Simon Lilly, ETH Zurich)

Water and hydrides in star forming regions 74%

(Prof. Dr. Arnold Benz)

ETH: Water in Star and

Planet Formation

Why observe water?

• Water is important in energetics (main coolant at

high density)

• Water is important for sticking grains to planetoids

• Water is a tracer for temperature, X-rays,

star and planet formation

• Water is important for life

• Water cannot be observed from the ground

QM and service module

Swiss hardware contributions:

1. Common Optics Assembly to H

2. Amplifier Box to HIFI

SPIRE

PACS

Heterodyne Instrument for the Far Infrared

Swiss hardware contributions:

1. Common Optics Assembly to H

2. Amplifier Box to HIFI

Common Optics Assembly housing

HIFI Common Optics Assembly

•Machining

•Spark erosion

•Heat treatment

•Final assembly

by

HTS Wallisellen,

(now RUAG)

Switzerland

Common

Optics

Assembly,

cQM (parts)

final machining pre-machined

Common

Optics

Assembly,

cQM

HTS Wallisellen,

Surface treatment

at ABB Zurich

Specified precision:

1 μm

at 60 cm total length

Riveting at RUAG, Emmen

Channel housing with one Mixer Subassembly

Common

Optics

Assembly

(Al mirrors)

TPD Delft (raw)

and

LFM Bremen

Common

Optics

Assembly

large

mirrors

Assembling the Common Optics

Assembly FM at HTS Wallisellen

Final integration and testing at SRON Groningen

Electrical wiring at SRON, NL

IF2 amplifier box

Mixer Subassembly boxes

Vibration test

Herschel cQM on multishaker

Time Line

ETH

Industry

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Phase A Phase B/C

Prodex proposal

submitted (phase A)

Herschel

launch Prodex proposal

submitted (phase B/C)

Learning optics, Project coordination, Specific science starts, Submiting proposals

Design studies amplifier, Final design amplifier box Software development

Institute of Astronomy,Radio Astronomy and Plasma Physics GroupEidgenössische Technische Hochschule Zürich

Swiss Federal Institute of Technology, Zürich

Summary of Experiences

1. Technologically very demanding project.

2. At Institute of Astronomy we have worked only with existing

manpower. Very small group!!

3. We have learned very much at ETH, and probably also

industry (HTS Wallisellen and Baumer electric).

4. Relation with industry without major problems. PRODEX

handled subtle negotiation and controlling with industrial

partner. VERY IMPORTANT!!

5. Delivery of hardware on schedule (our own!)

6. and to full satisfaction (no complaints yet).

7. Conclusion: PRODEX allows small groups at universities to

cooperate with industry in large projects.

Institute of Astronomy,Radio Astronomy and Plasma Physics GroupEidgenössische Technische Hochschule Zürich

Swiss Federal Institute of Technology, Zürich

Lessons Learnt

(optical part)

1. Start early in the project to get interesting part.

2. Have detailed design close to manufacturing.

3. Start early to talk with Swiss industry.

4. Space qualification not possible at ETH Zurich.

5. Watch communication between partners

(many components, many details)

The End