COBE Celebrates 35th Launch Anniversary

  • Released Monday, November 18, 2024
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Technicians work on the COBE (Cosmic Background Explorer) spacecraft in a clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The mission launched into an Earth orbit in 1989 to make an all-sky map of the cosmic microwave background, the oldest light in the universe. The conical silver shield protects the scientific instruments from direct radiation from the Sun and Earth, isolates them from radio-frequency interference from the spacecraft transmitters and terrestrial sources, and provides thermal isolation for a dewar containing liquid helium coolant.Credit: NASA/COBE Science Team

Technicians work on the COBE (Cosmic Background Explorer) spacecraft in a clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The mission launched into an Earth orbit in 1989 to make an all-sky map of the cosmic microwave background, the oldest light in the universe. The conical silver shield protects the scientific instruments from direct radiation from the Sun and Earth, isolates them from radio-frequency interference from the spacecraft transmitters and terrestrial sources, and provides thermal isolation for a dewar containing liquid helium coolant.

Credit: NASA/COBE Science Team

The COBE (Cosmic Background Explorer) satellite, launched Nov. 18, 1989, studied the origin and dynamics of the universe, including the theory that the universe originated in a hot, dense state and expanded and cooled to its present form, a process called the big bang.

One consequence of a hot origin for the universe is that a faint echo of radiation emitted by the original fireball should still fill the cosmos. In 1964, Arno Penzias and Robert Wilson of the Bell Telephone Laboratories, using a sensitive microwave antenna in Holmdel, New Jersey, found an unexplained noise in their data. It came from all parts of the sky with equal intensity. This radiation, an echo of the original fireball, is called the CMB (cosmic microwave background).

COBE’s Differential Microwave Radiometer showed for the first time that the CMB had an intrinsic anisotropy, meaning that intensity changes varied by 1 part in 100,000 from place to place. These tiny variations show how matter and energy were distributed when the universe was very young. Later, through processes still poorly understood, the variations developed into the large-scale structures we see in the universe today. COBE had produced the first baby picture of the cosmos.

The mission's Far Infrared Absolute Spectrophotometer instrument measured the CMB spectrum with a precision of 0.03%, demonstrating for the first time that it closely matches that of a blackbody — a perfect emitter and absorber — with a temperature of 2.725 K (about 454.8 degrees below zero Fahrenheit or –270.4 Celsius). This observation agrees well with predictions of the remnant glow from a cosmos originating in a hot big bang.

The Diffuse Infrared Background Experiment mapped absolute sky brightness from 1.25 microns to 240 microns and succeeded in detecting the cosmic infrared background. This cosmic core sample contains the cumulative emissions of stars and galaxies dating back to the epoch when they first began to form. These measurements constrain models of the history of star formation and the buildup of elements heavier than hydrogen, including those composing living organisms.

COBE investigators John Mather and George Smoot were awarded the 2006 Nobel Prize in physics for their work. COBE was retired on Dec. 23, 1993.

An artist’s concept of the COBE satellite in orbit with spacecraft elements identified. An unlabeled version is also available.Credit: NASA’s Goddard Space Flight Center

An artist’s concept of the COBE satellite in orbit with spacecraft elements identified. An unlabeled version is also available.

Credit: NASA’s Goddard Space Flight Center

The COBE spacecraft undergoes cleaning in a NASA Goddard clean room before being shipped for final integration prior to launch. Credit: NASA/Peter M. Baltzell

The COBE spacecraft undergoes cleaning in a NASA Goddard clean room before being shipped for final integration prior to launch.

Credit: NASA/Peter M. Baltzell

COBE is suspended without its shield and solar panels in a NASA Goddard clean room. The white structure at the top of the spacecraft is a dewar that at launch contained nearly 175 gallons (660 liters) of liquid helium to provide a stable ultracold (457° F below zero or –272° C) environment for the instruments. The liquid helium enabled cryogenic operations for 306 days, allowing the FIRAS and DIRBE instruments to completely map the sky with superlative sensitivity. FIRAS precisely measured the spectrum of the cosmic microwave background and DIRBE measured the cosmic infrared background for the first time.Credit: National Archives (255-CC-89-HC-288)

COBE is suspended without its shield and solar panels in a NASA Goddard clean room. The white structure at the top of the spacecraft is a dewar that at launch contained nearly 175 gallons (660 liters) of liquid helium to provide a stable ultracold (457° F below zero or –272° C) environment for the instruments. The liquid helium enabled cryogenic operations for 306 days, allowing the FIRAS and DIRBE instruments to completely map the sky with superlative sensitivity. FIRAS precisely measured the spectrum of the cosmic microwave background and DIRBE measured the cosmic infrared background for the first time.

Credit: National Archives (255-CC-89-HC-288)

The Far Infrared Absolute Spectrophotometer instrument precisely measured the spectrum of the cosmic microwave background, showing that it matched a blackbody — a perfect emitter and absorber — with a temperature of 2.725 K, providing strong support for a hot cosmic origin.Credit: NASA/COBE Science Team

The Far Infrared Absolute Spectrophotometer instrument precisely measured the spectrum of the cosmic microwave background, showing that it matched a blackbody — a perfect emitter and absorber — with a temperature of 2.725 K, providing strong support for a hot cosmic origin.

Credit: NASA/COBE Science Team

After stripping away foreground emission arising from dust, hot gas, and charged particles interacting with magnetic fields in our galaxy, COBE Differential Microwave Radiometer data revealed tiny variations in the temperature of the cosmic microwave background — the oldest light in the universe — for the first time. This image shows the entire sky using two years of observations; the central plane of our galaxy runs across the middle. Red indicates hotter regions, blue colder. The fluctuations are extremely faint, varying by only 1 part in 100,000 from the average temperature. These variations represent an imprint of the density contrast in the early universe, variations thought to have given rise to the structures that populate the universe today.Credit: NASA/COBE Science Team

After stripping away foreground emission arising from dust, hot gas, and charged particles interacting with magnetic fields in our galaxy, COBE Differential Microwave Radiometer data revealed tiny variations in the temperature of the cosmic microwave background — the oldest light in the universe — for the first time. This image shows the entire sky using two years of observations; the central plane of our galaxy runs across the middle. Red indicates hotter regions, blue colder. The fluctuations are extremely faint, varying by only 1 part in 100,000 from the average temperature. These variations represent an imprint of the density contrast in the early universe, variations thought to have given rise to the structures that populate the universe today.

Credit: NASA/COBE Science Team

This artist's concept shows COBE's original design, when it was to be launched as part of a space shuttle mission. During the hiatus in shuttle launches following the 1986 Challenger disaster, COBE was reconfigured to allow launch on an expendable Delta booster. COBE's diameter and mass were reduced by half. Other changes included deployable solar panels and a conical radiation shield that would unfold in orbit.Credit: NASA

This artist's concept shows COBE's original design, when it was to be launched as part of a space shuttle mission. During the hiatus in shuttle launches following the 1986 Challenger disaster, COBE was reconfigured to allow launch on an expendable Delta booster. COBE's diameter and mass were reduced by half. Other changes included deployable solar panels and a conical radiation shield that would unfold in orbit.

Credit: NASA

From the archives: COBE launches into orbit on Nov. 18, 1989.

Credit: NASA

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NASA's Goddard Space Flight Center. However, individual items should be credited as indicated above.

This page was originally published on Monday, November 18, 2024.
This page was last updated on Tuesday, November 19, 2024 at 6:35 PM EST.