Darwin (spacecraft)
Proposed ESA mission to detect Earth-like exoplanets via interferometry.
Darwin was a proposed ESA Cornerstone mission that would have used a constellation of spacecraft to directly detect Earth-like planets around nearby stars and search for evidence of life. The most recent design involved three free-flying telescopes flying in formation as an astronomical interferometer, with a fourth spacecraft acting as a beam combiner and communications hub. The study of this mission ended in 2007 with no further activities planned.
Quick Facts
- Operator
- ESA
- Launch rocket
- Soyuz-2/Fregat
- Launch site
- Kourou ELS
- Launch contractor
- Arianespace
- Orbit epoch
- planned
- Orbit regime
- Halo orbit
- Apsis
- apsis
Facts from the source article.
Did You Know?
- Planet Gliese 581 d, discovered in 2007, was considered a good candidate for the Darwin project.
- The earlier 'Robin Laurance configuration' included six 1.5 metre telescopes, a beam combiner spacecraft, and a separate power and communications spacecraft.
Concept
The Darwin spacecraft would have observed the universe in infrared light. This part of the spectrum was chosen because a star outshines an Earth-like planet by a billion times in visible light, but the contrast is much smaller in the infrared. To make these observations possible, every component along the optical path had to be passively cooled to 40 kelvins. The search for planets relied on a nulling interferometer. By introducing phase shifts into three beams, light from the central star would cancel itself out through destructive interference, while light from a planet, slightly offset from the star, would remain. The telescopes would operate in imaging mode to detect planets. Finding an Earth-like planet would have required about ten hours of observation spread over several months. A 2002 design with 1.5-metre mirrors would have needed roughly one hundred hours to obtain a spectrum of a potentially Earth-like world. If a suitable planet were found, scientists would take an infrared spectrum of its atmosphere to determine its chemistry. The presence of oxygen and water vapor could indicate life, since oxygen is highly reactive and large amounts would need continuous production, such as through photosynthesis. Beyond planet hunting, the telescopes would have been useful for general high-resolution infrared imaging, achieving milliarcsecond detail for studying various astrophysical processes.
Similar initiatives
Darwin shares a close conceptual and scientific resemblance with NASA’s Terrestrial Planet Finder interferometer. That NASA project was put on hold indefinitely according to the agency’s 2007 budget documents, and by June 2011 it had been reported as cancelled. A far larger and more costly space interferometer, the Hypertelescope, has been suggested by Antoine Labeyrie, featuring many free-flying telescopes in a spherical layout and focusing on interferometric imaging.
More in Space Probes of ESA, Japan, China, India and the USSR
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