The ESBO DS project Towards a balloon-based observatory René Duffard & José Luis Ortiz Instituto de Astrofísica de Andalucía - CSIC P. Maier 1, J. Wolf 1, T. Keilig 1, A. Krabbe 1, R. Duffard 4, J. L. Ortiz 4, S. Klinkner 1, M. Lengowski 1, T. Müller 5, C. Lockowandt 2, C. Krockstedt 2, N. Kappelmann 3, B. Stelzer 3, K. Werner 3, S. Geier 3,6, C. Kalkuhl 3, T. Rauch 3, T. Schanz 3, J. Barnstedt 3, L. Conti 3, L. Hanke 3, D. Angerhausen 7 1 Institute of Space Systems, University of Stu[gart, Germany, 2 Swedish Space Corporation, Sweden, 3 Institut für Astronomie und Astrophysik, Universität Tübingen, Germany, 4 Instituto de Astrofísica de Andalucía (CSIC), Spain, 5 Max-Planck-Institut für extraterrestrische Physik, Germany, 6 Institut für Physik und Astronomie, Universität Potsdam, Germany, 7 Center for Space and Habitability, Universität Bern, Swiaerland
European Stratospheric Balloon Observatory Content 1. Balloon-based telescopes 2. The ESBO DS Project 3. Planetary Science Applications
Balloon-based telescopes
Balloon-based telescopes PILOT, 2015 THISBE, 1969 STO-2, 2016 BLAST, 2006 Ph. Maier H2020 project ESBO DS
Balloon-based telescopes Typical flight parameters Gondola mass: o 500 2000 kg Flight altitude: o 30 to 40 km Flight duration: o 10 hours - ~ 40 days Launch sites: o Continental U.S. (short duration) o Kiruna, Sweden (mid- & long duration) o Antarctica (long duration) Alitutde [km] 35 30 20 10 0 Exemplary altitude profile (SUNRISE) Mid-duration flight (20-40 h) Long-duration flights (5 days / 55 days)
Why balloons? Balloon-based telescopes Observation conditions between ground & space, particularly: Access to additional spectral regions o o o UV Near- and Mid-IR Far-IR Practically no seeing o Enables diffraction limited spatial resolution Drastically reduced scintillation noise o Enables high photometric accuracy Practical implications: o o o Exchange of instruments Update & repair of instruments Refill of cryogens UV atmospheric transmission FIR atmospheric transmission Scintillation noise
Motivation Some technical challenges Sunrise (2009) PoGOLite (2011) Sunrise (2013) PoGOLite (2013)
Motivation Ground Balloons Space?
Motivation Ground Balloons Space European Stratospheric Balloon Observatory
ESBO
The ESBO DS Project European Stratospheric Balloon Observatory Design Study: Design study under H2020 call INFRADEV-01-2017 (RIA) Duration: 36 months (Mar 2018- Mar 2021) Total budget: 3.009.575 EUR Follow-on to the H2020 Project ORISON Conceptualisation of a European research infrastructure 2-tier approach: A) development and construction of a prototype UV/vis flight system B) conceptual design of a FIR balloon observatory, including supportive infrastructure European Stratospheric Balloon Observatory Design Study IAA-CSIC
3 ORISON consortium partners: ESBO DS Partners Universität Stuttgart (USTUTT), Institute of Space Systems 2 new partners: Max Planck Gesellschaft (MPG), Institute for extraterrestrial Physics Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Astrofísica de Andalucía Universität Tübingen (EKUT), Institute for Astronomy and Astrophysics Swedish Space Corporation (SSC)
ESBO DS Approach European Stratospheric Balloon Observatory o Regular flights with payload recovery and reflight o Proposal-based time allocation Mid term UV-NIR 0.5 m telescope o High-accuracy pointing (goal: 1 arcsec) o Suitable for UV Vis-NIR 1.5 m telescope o High photometric stability o Suitable for planetary science, exoplanets ESBO Infrastructure Governance Structure FIR 5 m telescope o less confusion noise than Herschel o Goal: 40 flight days per mission o Launch from Antarctica Proposal Tools 0.5 m telescope 1.5 m telescope Ground Systems 5 m telescope Data Pipelines
ESBO DS Approach 0.5 m UV/vis telescope 5 m FIR telescope Operating structure / concept / Prototype Feasibility/ First Design Draft/ Roadmap
ESBO DS Approach UV/visible Prototype (0.5 m)
Flight-ready Prototype Telescope/Platform 0.5 m UV-NIR Telescope 400-500 kg Gondola Coarse telescope stabilization in azimuth & elevation Exchangeable instruments Space for add-on instruments Goal - UV/vis (0.5 m) Instruments Highly sensitive imaging UVcamera (Uni Tübingen) Andor-camera for the visible range Image stabilization within the optical path (goal: ~ 1 arcsec) (1) - GPS Antenna (2) - Antenna boom (3) - Receiver (4) - Pivot (5) - Satellite antenna (6) - Elevation torque motor (8) - Gyro sensor (9) - Star tracker (10) - Batteries (11) Crush pad (13) - Add-on instrument (15) - Telescope (17) Reaction wheel
Main Telescope Parameters Current Telescope configuration Secondary Instrument Configuration Cassegrain Instrument Andor ixon Aperture 500 mm Main application Image stabilisation Focal ratio f/8 Wavelength range Sensor size Ca. 330 1000 nm 13.3 mm x 13.3 mm Pixel size 13 µm x 13 µm Scientific Application / Main Instrument Instrument Main application Main wavelength range Sensor size Custom MCP* UV Photometry 180 330 nm 40 mm Pixel size 20 µm x 20 µm Preferred FOV Ca. 32 arcmin UV MCP detector Andor ixon 888 *MCP = Micro Channel Plate
Expected Performance UV/vis Prototype (0.5 m) V-band sensitivity at SNR = 5 Angular resolution (diffraction limit)
Goal FIR (5 m) Extended interest in balloon-based FIR observations o Current FIR state-of-the-art: SOFIA, 2.5 m mirror o Several existing balloons (BLAST, PILOT, STO, up to 2.5 m mirrors) o Next step: increase on confusion limit of Herschel (3.5 m, requires 5 m+ mirror dimension) o 5x2.5 m elliptical would have similar area as Herschel mirror o Uncooled telescope temperature: ca. 200 K, might be possible down to 180 K (vs. 230 K on SOFIA) o Instruments, Sensitivity & spectral resolution TBD Angular resolution [arcsec] 100 10 1 0.1 0.01 0.001 ESBO angular resolution ISO SOFIA Spitzer Herschel ESBO 5m SPICA JWST E-ELT ALMA 1 10 100 1000 Wavelength [µm]
Goal FIR (5 m) Potential scientific observations ISM/Star Formation: o High spatial resolution line surveys (e.g. CII, NII, OI, HD) o 100 µm continuum survey @ 5 arcsec resolution (SOFIA: 10 as, Herschel: 7 as) Planetary Science / Solar System o Atmospheric gas abundances & vertical distribution o E.g. H2O, O2, HCl (Mars, Venus, satellites, small bodies, comae) Min. detectable line flux [W/m^2] Potential Sensitivities 1.E-12 (900 s exposure time, 4σ, ca. 44 khz, i.e. 0.003 to 0.01 km/s resolution) 1.E-13 1.E-14 1.E-15 1.E-16 1.E-17 0 50 100 150 200 250 Wavelength [µm] SOFIA 1km/s ESBO 1km/s SOFIA 100km/s ESBO 100km/s
Potential Timeframe
Summary Prototype (0.5m telescope) flying in 2020 Recovery of the telescope and instruments o Exchange of instruments o Update & repair of instruments o Refill of cryogens Five meter telescope planned for the near future