This illustration shows the Lucy spacecraft passing one of the Trojan Asteroids near Jupiter.
NASA’s long-term “Lucy” mission to visit eight mysterious asteroids will perform a flyby of its home planet this weekend.
As reported by the space agency, the spacecraft will swoop near Earth exactly one year after its launch, on Sunday, October 16, 2022 to use this planet’s gravity to set itself on a course toward the Jupiter Trojan asteroids.
Trojan asteroids are ancient remnants of the early Solar System clustered in two “swarms” leading and following Jupiter in its path around the Sun.
The $450 million “Discovery”-class spacecraft will skim Earth’s atmosphere just 220 miles/350 kilometers above the surface at 7:04 a.m. EDT this Sunday. However, this closest approach will be over the Pacific Ocean at night.
Viewers in the western half of North America using binoculars or a telescope with a wide field of view can watch Lucy emerge from Earth’s shadow at 4:26am PDT, 5:26am MDT and 1:26am HST. Full details and charts are provided by NASA. From North America Lucy will be about 6th-7th magnitude, so not visible to the naked eye.
It will also be visible from Australia.
The sling-shot will gain the spacecraft valuable orbital energy to travel to the remote asteroids during the remainder of its 12 year mission. However, Lucy will return for a second Earth flyby in two years before it can cross the main asteroid belt and visit asteroid Donaldjohanson and four Trojan asteroids: Eurybates and its satellite Queta, Polymele and its yet unnamed satellite Leucus, then Orus.
A third gravity Earth flyby in 2030 will route Lucy to Patroclus-Menoetius, a binary asteroid pair behind the Trojan asteroids.
There is a concern that Lucy could this weekend collide with one of the many thousands of satellites in Earth’s orbit. “The Lucy team has prepared two different maneuvers,” said Coralie Adam, Lucy deputy navigation team chief from KinetX Aerospace in Simi Valley, California. “If the team detects that Lucy is at risk of colliding with a satellite or piece of debris, then—12 hours before the closest approach to Earth—the spacecraft will execute one of these, altering the time of closest approach by either two or four seconds. This is a small correction, but it is enough to avoid a potentially catastrophic collision.”
Because it will be flying towards Earth from the direction of the Sun Lucy will be able to take images of the nearly full Earth and Moon.
“I’m especially excited by the final few images that Lucy will take of the Moon,” said John Spencer, acting deputy project scientist at the Southwest Research Institute (SwRI). “Counting craters to understand the collisional history of the Trojan asteroids is key to the science that Lucy will carry out, and this will be the first opportunity to calibrate Lucy’s ability to detect craters by comparing it to previous observations of the Moon by other space missions.”
Wishing you clear skies and wide eyes.
