SPICA (spacecraft)

SPICA telescope
Names HII-L2
Mission type Infrared astronomy
Operator JAXA / ESA
Website www.spica-mission.org
jaxa.jp/SPICA
Mission duration 3 to 5 years [1][2]
Spacecraft properties
Launch mass 3,650 kg (8,050 lb)[3]
Payload mass 600 kg (1,300 lb)
Dimensions 5.9 m × 4.5 m (19 ft × 15 ft)[3]
Power 3 kW from a 14 m2 solar array[3]
Start of mission
Launch date 2032 (proposed)[4]
Rocket H3 Launch Vehicle[3]
Launch site LA-Y, Tanegashima
Contractor Mitsubishi Heavy Industries
Orbital parameters
Reference system Sun–Earth L2
Regime Halo orbit
Epoch planned
Main telescope
Type Ritchey-Chrétien
Diameter 2.5 m (8.2 ft)
Collecting area 4.6 m2 [5]
Wavelengths from 12 µm (mid-infrared)
to 230 µm (far-infrared)[1][2]
Instruments
SMI SPICA Mid-Infrared Instrument[1]
SAFARI SpicA FAR-infrared Instrument[1]

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA), initially called HII-L2 after the launch vehicle and orbit, is a proposed infrared space telescope, follow-on to the successful Akari space observatory. It is a collaboration between European and Japanese scientists, which was selected in May 2018 by the European Space Agency (ESA) as a finalist for the next Medium class Mission 5 of the Cosmic Vision programme. Its sensitivity would be more than two orders of magnitude over both Spitzer and Herschel space telescopes.

History

In Japan, SPICA was first proposed in 2007 as a large Strategic L-class mission,[6][7][8] and in Europe it was proposed to ESA's Cosmic Vision programme (M1 and M2),[6] but an internal review at ESA at the end of 2009 suggested that the technology readiness for the mission was not adequate.[9][10][11] In May 2018, it was selected as one of three finalists for the Cosmic Vision Medium Class Mission 5 (M5) for a proposed launch date of 2032.[4]

Overview

The concept is a collaboration between the Japan Aerospace Exploration Agency (JAXA) and the European Space Agency (ESA). If funded, the telescope would be launched on JAXA's H3 launch vehicle.

The Ritchey-Chrétien telescope's 2.5-metre mirror (similar size to that of the Herschel Space Observatory) would be made of silicon carbide, possibly by ESA given their experience with the Herschel telescope. The spacecraft's main mission would be the study of star and planetary formation. It would be able to detect stellar nurseries in galaxies, protoplanetary discs around young stars, and exoplanets, helped by its own coronograph for the latter two types of objects.

Description

The observatory would feature a far-infrared spectrometer and is proposed to be deployed in a halo orbit around the L2 point. The design proposes to use V-groove radiators and mechanical cryocoolers rather than liquid helium to cool the mirror to below 8 K (−265.15 °C; −445.27 °F)[2] (versus the 80 K or so of a mirror cooled only by radiation like Herschel's) which provides substantially greater sensitivity in the 10–100 μm infrared band (IR band); the telescope is intended to observe in longer wavelength infrared than the James Webb Space Telescope. Its sensitivity would be more than two orders of magnitude over both Spitzer and Herschel space telescopes.[2]

Large-aperture Cryogenic Telescope

SPICA would employ a 2.5 m diameter Ritchey-Chretien telescope with a field of view of 30 arc minutes.[12]

Focal-Plane Instruments[12]
  • SMI (SPICA Mid-infrared Instrument): 20–40 μm
    • SMI-LRS (Low-Resolution Spectroscopy): 17-36 μm. It aims at detecting PAH dust emission as a clue of distant galaxies and emission of minerals from planet formation regions around stars.
    • SMI-MRS (Mid-Resolution Spectroscopy): 18-36 μm. Its high sensitivity for line emission with a relatively high wavelength resolution (R = 2,000) enables characterization of distant galaxies and planet formation regions detected by SMI-LRS.
    • SMI-HRS (High-Resolution Spectroscopy): 12-18 μm. With its extremely high wavelength resolution (R = 28,000), SMI-HRS can study the dynamics of molecular gas in planet formation regions around stars.
  • SAFARI (SPICA Far-infrared instrument): 34–210 μm

Objectives

As in the name, the main objective is to make advancement in the research of cosmology and astrophysics. Specific research fields include:

  • The birth and evolution of galaxies
  • The birth and evolution of stars and planetary systems
  • The evolution of matter

Discovery science

  • Constraints on the emission of ground state Н2 emission from the first (population III) generation of stars
  • The detection of biomarkers in the mid-infrared spectra of exo-planets and/or the primordial material in protoplanetary disks
  • The detection of Н2 haloes around galaxies in the local Universe
  • With sufficient technical development of coronagraphic techniques: the imaging of any planets in thehabitable zone in the nearest few stars
  • The detection of the far infrared transitions of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium. The very large molecules thought to comprise the PAHs, and which give rise to the characteristic features in the near-infrared, have vibrational transitions in the far-infrared which are widespread and extremely weak
  • The direct detection of dust formation in super novae in external galaxies and the determination of the origin of the large amounts of dust in high redshift galaxies

See also

References

  1. 1 2 3 4 "Instruments oboard SPICA". JAXA. Retrieved 2016-05-11.
  2. 1 2 3 4 SPICA Mission. SPICA Home Site.
  3. 1 2 3 4 SPICA - a large cryogenic infrared space telescope Unveiling the obscured Universe. (PDF). P.R. Roelfsema, et al. arXive; 28 March 2018.doi:10.1017/pas.2018.xxx
  4. 1 2 "ESA selects three new mission concepts for study". Retrieved 10 May 2018.
  5. ↑ SPICA/SAFARI Fact Sheet. (PDF)
  6. 1 2 SPICA - Current status. JAXA.
  7. ↑ "The Space Infrared Telescope for Cosmology & Astrophysics : Revealing the Origins of Planets and Galaxies".
  8. ↑ Goicoechea, J. R.; Isaak, K.; Swinyard, B. (2009). "Exoplanet research with SAFARI: A far-IR imaging spectrometer for SPICA". arXiv:0901.3240 [astro-ph.EP].
  9. ↑ SPICA technical review report. ESA. 8 December 2009.
  10. ↑ "SPICA's Mission". SPICA Website. JAXA. Archived from the original on July 28, 2011. Retrieved January 11, 2011.
  11. ↑ "A new start for the SPICA mission" (PDF). JAXA. February 2014. Retrieved 4 July 2014.
  12. 1 2 "Instruments onboard SPICA". www.ir.isas.jaxa.jp. Retrieved 2016-05-02.
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