Most of the members of the Astrochemistry Laboratory who make scientific telescopic observations do the majority of their work using the technique of infrared spectroscopy. Infrared radiation has the advantage that it can penetrate larger amounts of dust and gas than visible radiation can. As a result, infrared radiation allows astronomers to probe regions of space that are hidden from normal sight. For example, infrared observations allow astronomers to study 'protostars,' stars that are in the process of forming. These stars are deeply embedded in the cloud of gas, dust, and ice from which they are forming and are completely hidden from view at optical wavelengths.

This figure provides a schematic view of how a protostar can be probed at infrared wavelengths in order to learn more about the star and its surroundings. The forming star emits large amounts of radiation, most of which is absorbed by the nearby surrounding dust. The absorbed radiation heats the dust, which subsequently tries to cool by re-emitting the energy as infrared 'heat' radiation having a broad blackbody energy distribution. This longer wavelength radiation is better able to penetrate the dust and gas in the cloud and can escape to be detected by astronomers. To learn more about how we analyse the light that comes from the stars click here.

One of the powers of infrared astronomy is intimately associated with one of its chief disadvantages. The propensity of molecules to absorb certain frequencies of infrared radiation make it possible to identify molecules in space, but this same property causes some frequencies of infrared radiation to be absorbed in the Earth's atmosphere before they reach the ground. As a result, infrared astronomy cannot be done from ground-based telescopes as some frequencies. For example, CO₂, and especially H₂O, in the Earth's atmosphere block most of the infrared radiation from space with the exception of photons falling in infrared 'windows' between about 3300-2500, 2200-1800, 1400-970, and 950-770 cm^-1 (3-4, 4.5-5.5, 7-10.3, and 10.5-13 microns). The portion of the infrared spectrum that can be studied is increased immensely, however, if you can make observations in the Earth's atmosphere at altitudes above 40,000 feet where you are above most of the atmospheric H₂O.

In the past this has been done using the Kuiper Airborne Observatory (KAO), a C-141 Starlifter in which a 80 cm telescope is mounted. Here is a picture of the KAO and a picture of Drs. Jesse Bregman, Scott A. Sandford, and Farid Salama , taking data on the KAO. This aircraft was recently retired and as a replacement NASA is currently building a larger airborne observatory called the Stratospheric Observatory For Infrared Astronomy (SOFIA), a 747 that will carry a 2.5 meter diameter telescope.