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

2. UH, March 2001 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. UH, March 2001 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. UH, March 2001 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. UH, March 2001 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. UH, March 2001 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  -studies Technology studies MIR studies

7. UH, March 2001 7

8. 8

9. 9 NASA re-scope Rationale Phase A study near completion, 2 validated concepts have been studied in detail NASA estimates of the cost of each concept exceed the available resources Mirror technology program has been highly successful at demonstrating performance but mirror blank preparation and segment polishing remain on the critical path - basically, there is not enough time to polish 8m aperture No time to fly Nexus and learn from it Better de-scope now than wait until later

10. UH, March 2001 10 What to do? Follow the ASWG recommended de-scope pathway 4. Field 3. Spatial resolution 2. Number of targets 1. Sensitivity Maintain “First Light in the Universe” capability Require 1g testability (kill Nexus) Reduce dependency on a number of new, high-risk technologies Enable diversity in launchers and test chambers Maintain the approved NASA acquisition strategy

11. UH, March 2001 11 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

12. UH, March 2001 12

13. UH, March 2001 13

14. UH, March 2001 14 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

15. UH, March 2001 15 Science review by ISWG Whether the capabilities of the revised NGST are sufficiently compelling as to warrant the projected total cost of the project, particularly in the light of what other capabilities will be available to astronomers in ~2009 Which science goals are the most important and the accomplishment of which should serve as the benchmarks for mission success and which should be used as guides during the design of the mission Which science goals should not be mission design drivers but are nonetheless sufficiently compelling that they should be achieved if at all possible Which design parameters (e.g., telescope diameter, image quality, wavelength coverage, pointing and other operational constraints, telescope temperature, etc) are likely to have the strongest impacts on the science return of NGST Whether the Design Reference Mission represents the scientific usage of NGST appropriately or does it need revision in light of the re-scope

16. UH, March 2001 16 ST-ECF NGST activities Current situation and near-term plans European NGST activities in 2001 ESA internal technology development studies ESA external studies MEMS spectrograph I MEMS spectrograph II MOS backup MIR definition study NIRSpec definition MISC participation and MIR instrument definition study SST activities, ISWG support Science management planning

17. UH, March 2001 17 ST-ECF contributions ESA/NASA partnership working group (Benvenuti) ESA NGST Task Group (Benvenuti - ex-officio) ESA NGST Study Science Team (Fosbury) NGST US ad hoc Science Working Group - ASWG (Fosbury) LAS/Dornier ESA-funded spectrograph study (Cristiani *) Laben on-board data management study (Albrecht - ex-officio)) NGST US Interim Science Working Group - ISWG (Fosbury - ex-officio) ESA F2/3 proposal and Study Report writing (Fosbury) European NGST science management plan (Fosbury, Albrecht) European NGST public and community information (ST-ECF Newsletter - Fosbury; Hubble European Space Agency Information Centre - Christensen, Benvenuti; Euroseminars - various) * Resigned due to conflict of interest

18. UH, March 2001 18 Planning for 2001 Set up European NGST Instrument Science Report series 1.Red-leak analysis (Cristiani et al.) 2.NIRSpec aperture optimisation (Arribas et al.) Support current ESA-funded  -studies and SST evaluations Provide appropriate PR and community information Create detailed science management plan for European operations Create infrastructure for instrument physical modelling (based on HST experience) Assist ESA in NIRSpec definition by carrying out performance studies Assist ESA/MISC in MIR by carrying out performance studies** **although ECF staff members have little specific MIR expertise.

19. UH, March 2001 19 Long-term planning European instrument science activities Need to start at instrument definition phase (2001) Operational support for NGST in general and European instruments in particular Note that, for the US, NGST is a low-cost operation (compared to HST). It will be essential for Europe to play an operational role.

20. UH, March 2001 20 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)

21. UH, March 2001 21 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)

22. UH, March 2001 22 MEMS developments 90  m

23. UH, March 2001 23 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.