TPF-I SWG Report - Exoplanet Exploration Program - NASA

C HAPTER 2
Classical interferometry
• Same as above
• Operate over the wavelength range of 3–15 µm
• A synthesized field of view (FOV) of 100–1000 resolution elements in two orthogonal
coordinates
• A dynamic range of 100:1
• 1000 spectral elements
2.1.3 Mission Summary
Performance Requirement
As a minimum, TPF-I must be able to detect planets with half the area of the Earth, and the Earth’s
geometric albedo, searching the entire HZ of the core-group stars with 90% completeness per star. Flux
ratios must be measured in three broad wavelength bands, to 10% accuracy, for at least 50% of the
detected terrestrial planets. The spectrum must be measured for at least 50% of the detected terrestrial
planets—to give the equivalent widths of H 2 O, and O 3 to an accuracy of 20%.
Performance Goal
As a goal, TPF-I must be able to detect planets with half the area of the Earth, with Earth’s geometric
albedo, searching the entire HZ of the 150 stars with 90% completeness. The flux ratio must be
measured in three broad wavelength bands to 10% accuracy for at least 50% of the detected terrestrial
planets. The spectrum must be measured—for at least 50% of the detected terrestrial planets—to give the
equivalent widths of H 2 O, and O 3 in the infrared to an accuracy of 20%. Further, we desire that the
mission search an extended group of stars defined as those systems of any type in which all or part of the
HZ can be searched.
2.2 Wavelength Coverage
As shown in Figure 2-1, the Earth’s brightness peaks at 10 μm. As discussed below, we specify the
wavelength coverage for TPF-I as being between 6.5 and 15 μm to detect CH 4 , O 3 , and H 2 O with a goal
of 6.5–18 μm to include CO 2 .
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