After 21 years of orbiting in space, a defunct NASA spacecraft has finally made its way back to Earth. The spacecraft called the Compton Gamma Ray Observatory (CGRO), was a groundbreaking mission. It helped scientists study the high-energy universe and discover some of the most mysterious objects in the cosmos. Its return to Earth marks the end of an era of space exploration. This return also presents a unique opportunity for researchers to study the effects of long-term spaceflight on hardware.
The CGRO was the second of NASA’s Great Observatories. NASA launched CGRO on April 5, 1991. It consisted of a series of four space telescopes that aimed to study the universe in different wavelengths of light. The CGRO was designed to detect gamma rays, the most energetic form of light. It can reveal the most extreme and violent processes in the universe, such as black holes and exploding stars.
For nine years the defunct NASA spacecraft orbited the Earth at an altitude of 450 miles. It collected data that revolutionized our understanding of the high-energy universe. It made several groundbreaking discoveries. These include the first identification of gamma-ray bursts and the discovery of intense flashes of gamma rays. These rays can last for just a few seconds but release as much energy as the sun does in its entire lifetime.
However, by 2000, the CGRO was running out of fuel and nearing the end of its operational life. There was a risk of the spacecraft falling out of orbit and potentially causing damage on Earth. However, NASA decided to de-orbit the CGRO and bring it back to Earth in a controlled manner.
On June 4, 2000, NASA adjusted CGRO’s orbit to send it on a trajectory. This trajectory would cause it to re-enter Earth’s atmosphere. However, the spacecraft did not completely burn up upon re-entry, and some pieces of debris fell into the Pacific Ocean. At the time, NASA estimated that about 1,000 pounds of debris made it to the surface. However, the exact amount was difficult to determine.
Nearly 21 years after the CGRO’s re-entry, in April 2021, an expedition headed by ocean explorer Victor Vescovo discovered the spacecraft’s wreckage on the South Pacific Ocean’s seafloor. NASA found the debris using a sonar-equipped autonomous underwater vehicle. The vehicle detected several pieces of the spacecraft scattered across an area of about 100 meters.
The discovery of the CGRO’s debris presents a unique opportunity for researchers to study the effects of long-term spaceflight on hardware. The spacecraft was exposed to extreme conditions in space, including high levels of radiation and temperature fluctuations, and its return to Earth offers a chance to examine how those conditions affected its components.
In conclusion, the return of the Compton Gamma Ray Observatory to Earth after 21 years marks the end of a groundbreaking mission that revolutionized our understanding of the high-energy universe. While the spacecraft’s re-entry was not entirely successful, the discovery of its debris offers a unique opportunity for researchers to study the effects of long-term spaceflight on hardware and gain insights that could inform future space missions.