NASA’s Lucy spacecraft prepares to swing by Earth

On Oct. 16, at 7:04 a.m. EDT, NASA’s Lucy spacecraft, the primary mission to the Jupiter Trojan asteroids, will skim the Earth’s environment, passing a mere 220 miles (350 kilometers) above the floor. By swinging previous Earth on the primary anniversary of its launch, Lucy will acquire a number of the orbital power it must journey to this never-before-visited inhabitants of asteroids.

The Trojan asteroids are trapped in orbits across the sun on the similar distance as Jupiter, both far forward of or behind the enormous planet. Lucy is presently one yr right into a twelve-year voyage. This gravity help will place Lucy on a brand new trajectory for a two-year orbit, at which era it’s going to return to Earth for a second gravity help. This second help will give Lucy the power it must cross the principle asteroid belt, the place it’s going to observe asteroid Donaldjohanson, after which journey into the main Trojan asteroid swarm. There, Lucy will fly previous six Trojan asteroids: Eurybates and its satellite Queta, Polymele and its but unnamed satellite, Leucus, and Orus. Lucy will then return to Earth for a 3rd gravity help in 2030 to re-target the spacecraft for a rendezvous with the Patroclus-Menoetius binary asteroid pair within the trailing Trojan asteroid swarm.

For this primary gravity help, Lucy will seem to strategy Earth from the course of the sun. Whereas because of this observers on Earth will be unable to see Lucy within the days earlier than the occasion, Lucy will be capable of take photographs of the almost full Earth and moon. Mission scientists will use these photographs to calibrate the devices.

Lucy’s trajectory will carry the spacecraft very near Earth, decrease even than the Worldwide House Station, which implies that Lucy will cross by a area stuffed with earth-orbiting satellites and particles. To make sure the protection of the spacecraft, NASA developed procedures to anticipate any potential hazard, and if wanted, to execute a small maneuver to keep away from a collision.

“The Lucy staff has ready two completely different maneuvers,” says Coralie Adam, Lucy deputy navigation staff chief from KinetX Aerospace in Simi Valley, California. “If the staff detects that Lucy is prone to colliding with a satellite or piece of particles, then—12 hours earlier than the closest strategy to Earth—the spacecraft will execute considered one of these, altering the time of closest strategy by both two or 4 seconds. It is a small correction, but it surely is sufficient to keep away from a probably catastrophic collision.”

Lucy shall be passing the Earth at such a low altitude that the staff needed to embody the impact of atmospheric drag when designing this flyby. Lucy’s giant solar arrays enhance this impact.

“Within the authentic plan, Lucy was truly going to cross about 30 miles nearer to the Earth,” says Wealthy Burns, Lucy challenge supervisor at NASA’s Goddard House Flight Heart in Greenbelt, Maryland. “Nonetheless, when it grew to become clear that we’d need to execute this flyby with one of many solar arrays unlatched, we selected to make use of a little bit of our gas reserves in order that the spacecraft passes the Earth at a barely larger altitude, decreasing the disturbance from the atmospheric drag on the spacecraft’s solar arrays.”

At round 6:55 a.m. EDT, Lucy will first be seen to observers on the bottom in Western Australia (6:55 p.m. for these observers). Lucy will shortly cross overhead, clearly seen to the bare eye for a couple of minutes earlier than disappearing at 7:02 a.m. EDT because the spacecraft passes into the Earth’s shadow. Lucy will proceed over the Pacific Ocean in darkness and emerge from the Earth’s shadow at 7:26 a.m. EDT. If the clouds cooperate, sky watchers within the western United States ought to be capable of get a view of Lucy with the help of binoculars.

“The final time we noticed the spacecraft, it was being enclosed within the payload fairing in Florida,” stated Hal Levison, Lucy principal investigator on the Southwest Analysis Institute (SwRI) Boulder, Colorado workplace. “It’s thrilling that we can stand right here in Colorado and see the spacecraft once more. And this time Lucy shall be within the sky.”

Lucy will then quickly recede from the Earth’s neighborhood, passing by the moon and taking a number of extra calibration photographs earlier than persevering with out into interplanetary space.

“I am particularly excited by the ultimate few photographs that Lucy will take of the moon,” stated John Spencer, appearing deputy challenge scientist at SwRI. “Counting craters to grasp the collisional historical past of the Trojan asteroids is essential to the science that Lucy will perform, and this would be the first alternative to calibrate Lucy’s potential to detect craters by evaluating it to earlier observations of the moon by different space missions.”