Herschel
Full Name: Herschel Space Observatory
Phase: Development
Launch Date: May 14, 2009
Mission Project Home Page: http://herschel.jpl.nasa.gov/
Program(s): Cosmic Origins
The Herschel Space Observatory is a space-based telescope that will study the Universe by the light of the far-infrared and submillimeter portions of the spectrum. It is expected to reveal new information about the earliest, most distant stars and galaxies, as well as those closer to home in space and time. It will also take a unique look at our own Solar System.
Herschel is the fourth Cornerstone mission in the European Space Agency’s Horizon 2000 program. Ten countries, including the United States, are participation in its design and implementation. It is scheduled to be launched in 2008, and is expected to remain an active observatory for at least three years. Originally called “FIRST,” for “Far InfraRed and Submillimeter Telescope,” the spacecraft was renamed for Britain’s Sir William Herschel, who discovered in 1800 that the spectrum extends beyond visible light into the region we today call “infrared.”
Herschel’s namesake will give scientists their most complete look so far at the large portion of the Universe that radiates in far-infrared and submillimeter wavelengths. With a primary mirror 3.5 meters in diameter, Herschel will be the largest infrared telescope sent into space as of its launch date. It will focus light onto three instruments called HIFI, SPIRE, and PACS, which will enable Herschel to be the first spacecraft to observe in the full 60-670 micron range.
The far-infrared and submillimeter wavelengths at which Herschel will observe are considerably longer than the familiar rainbow of colors that the human eye can perceive. Yet, this is a critically important portion of the spectrum to scientists because it is the frequency range at which a large part of the universe radiates.
Much of the Universe consists of gas and dust that is far too cold to radiate in visible light or at shorter wavelengths such as x-rays. However, even at temperatures well below the most frigid spot on Earth, they do radiate at far-infrared and submillimeter wavelengths.
Stars and other cosmic objects that are hot enough to shine at optical wavelengths are often hidden behind vast dust clouds that absorb the visible light and re-radiate it in the far-infrared and submillimeter range.