Next Generation Space Telescope Status - Spring 2001 Bob Fosbury (ST-ECF) stecf/

1. Next Generation Space Telescope • Status - Spring 2001 • Bob Fosbury (ST-ECF) • http://www.stecf.org/

2. Science goals • See first-light in the Universe • Observe the origin & evolution of galaxies • Study structure & chemical enrichment of Universe • Study star and planet formation • In practice, these goals are represented by the Design Reference Mission (DRM)

3. The NGST • A collaboration between NASA, ESA and the Canadian Space Agency (CSA) • Observatory launched to an L2 halo orbit • Sun-Earth Lagrangian point, about 1.5Mkm away • Deployable, lightweight optics • Passive cooling • => sunshield

4. The instruments • A near-infrared camera (0.6 – 5 µm) • NASA + CSA • A near-infrared multi-object spectrograph (1 – 5 µm) • ESA + NASA • A mid-infrared camera/spectrograph(5 – 28 µm) • Europe + NASA

5. Europe’s rôle • Provision of the NIR spectrograph by ESA • (detectors and MEMS slit-selector supplied by NASA) • European National contributions to the mid-infrared instrument (around 50%- probably optics and bench) • ESA contributions to the spacecraft • (details not yet decided) • ESA support of observatory operations

6. Project status • NASA • Phase 1 (A/Early B) - 2 prime contractors • Downselect late 2001 • Technology development programme • Issue instrument AO mid-2001 • ESA • F2 selection: AWG, SSAC, SPC - late 2000 • Instrument d-studies • Technology studies • MIR studies

8. Recent re-scope exercise • Increase areal density of mirror from 15 to 20+ kg m-2 • Allows 1g testing • Reduce aperture from 8 to ~6.5m • Allows launch (mass) and time for polishing • Heat telescope to 45-50K • Allows active thermal control

10. Performance implications • Point source • Around 0.5m in limiting sensitivity • About a factor 2.3 in exposure time for fixed magnitude and s/n • Due to decreased aperture 8 -> 6.5m • Some thermal background added by warm telescope above 25µm - roughly another half magnitude in limiting sensitivity

11. ESA pre-Phase-A studies (1998–99) • Telescope & Payload Suite • Contractors: Dornier Satellitensysteme, Alcatel Space, LAS (Marseilles) • & UK Astronomy Technology Centre (Edinburgh) • Science Leads: Olivier Le Fevre (LAS), Gillian Wright (UK-ATC) • Multi-Object/Integral Field Spectrograph • Contractors: Laboratoire d’Astronomie Spatiale (Marseille) & Dornier • Satellitensysteme • w. Durham, ESO, Cambridge, MPE & Leiden • Science Lead: Olivier Le Fevre (LAS) • Visible Wavelength Camera/Spectrograph • Contractors: Matra-Marconi Space • w. Dornier Satellitensysteme, Leicester, MSSL, LAS, UCL & Obs. Paris • Science Lead: Martin Ward (Leicester) • On-Board Data Management • Contractors: Laben w. Dornier Satellitensysteme, Istituto di Fisica Cosmica • (Milan), Arcetri, LAS, Leicester & Univ. College Dublin • Science Lead: Patrizia Caraveo (IFC) • Other Spacecraft Subsystems (In-house)

12. Current NIRSpec studies • MEMS-based Near-IR Multi-Object Dispersive Spectrograph I(175 kK) • Contractors: Astrium & Laboratoire d’Astronomie Spatiale (Marseille) • w. Durham, ESO,Cambridge, MPE & Leiden • Science Lead: Olivier Le Fevre (LAS) • MEMS-based Near-IR Multi-Object Dispersive Spectrograph II(175 kK) • Contractors: Alcatel & Laboratoire d’Astronomie Spatiale (Marseille) • Science Lead: Denis Burgarella (LAS) • Alternatives to MEMS for slitmasks for a Near-IR Multi-Object Spectrograph(100 kK) • ITT Issued: December 2000 • Closing Date: February 23 • Update to Integral Field Spectrograph (75 kK) • Contractors: Laboratoire d’Astronomie Spatiale (Marseille) & Astrium w. Durham, ESO, Cambridge, MPE & Leiden • Science Lead: Olivier Le Fevre (LAS)

13. 90m MEMS developments

14. Science operations • Simpler process than HST • Different orbit • Longer observations • Archive volume is tiny cf. ESO • Europe will have a direct rôle • Instrument science for NIRSpec and possibly the MIR • Archiving, User Support, PR etc.