A rocket carrying a NASA spacecraft was launched on a first-ever mission to study mysterious clouds that float 80 kilometres above Earth.
The noctilucent clouds, which cluster around the polar regions and can only been seen at night, have appeared more often and grown brighter in recent years. Scientists are puzzled by the changes, but some suggest they may be due to global climate change.
Launched on Wednesday, the spacecraft, which will spend two years studying the ice clouds, will try to answer basic questions including why the clouds form and whether human-caused global warming is responsible for the changes. It is dubbed AIM, short for Aeronomy of Ice in the Mesosphere.
"We are exploring clouds literally on the edge of space," principal investigator James Russell of Hampton University said at a press conference earlier this month.
Mounted on a Pegasus rocket that was carried aloft by a special aircraft, it was air-launched over the Pacific Ocean shortly before 1:30 pm (local time) and boosted into an orbit about 595 kilometeres above Earth.
Launch and mission managers applauded after the spacecraft successfully separated from the rocket. Ground controllers continued to monitor the spacecraft's health.
Everything "appears to be right on the money," said AIM launch commentator George Diller.
The Pegasus rocket, built by Orbital Sciences Corp, featured Virginia Tech logos on its side in memory of the 32 students and teachers who died in a school rampage last week.
One of the mission's scientists, deputy principal investigator Scott Bailey, works at Virginia Tech.