Nasa's flying observatory has touched down in New Zealand again for another season of night-flying missions to study the skies of the Southern Hemisphere.
The Stratospheric Observatory for Infrared Astronomy (Sofia), a highly modified Boeing jetliner and huge internal telescope, arrived in Christchurch from Honolulu shortly after 11am today.
For the next two months, the world's largest flying observatory and its crew of scientists, astronomers, mechanics and technicians are scheduled to make several scientific night flights out of the US National Science Foundation's Antarctic Programme facility at Christchurch International Airport where it has been a regular visitor in recent years.
One of the major missions next month will be a look at the Kuiper Belt Object "2014 MU69", which Nasa's New Horizons spacecraft will fly past on January 1, 2019. The spacecraft made history by exploring Pluto and its moons two years ago.
Sofia, the Herald understands, will measure it and see what debris might be in the spacecraft's path.
Other flights will look at star formation, astrochemistry, as well as the large and small Magellanic clouds.
The Boeing 747SP, built in the late 70s as a Pan Am passenger plane, has had hundreds of seats removed and instead has been fitted with a giant gyro-stabilised highly sensitive 2.7m-diameter telescope and Nasa-style control centre.
Once the plane reaches an altitude of 10.6km, a specially fitted door opens for the telescope to peek out.
It makes observations that are impossible for even the largest and highest of ground-based telescopes as the plane flies at an altitude of 12-14km, which puts it above 99 per cent of the Earth's infrared-blocking water vapour layer.
The aircraft also carries heavier, more powerful instruments than space-based observatories, which can also be changed and upgraded for different missions.
The observatory's position, along with its suite of seven highly specialised instruments, make it ideally suited for studying a range of astronomical objects and phenomena, including the life cycle of stars, formation of new solar systems, black holes at the centre of galaxies, nebulae and interstellar dust, complex molecules and the planets, comets and asteroids in our solar system.
Last year, the Herald joined Nasa on one of its missions. Read about it here.