NASA’s Lucy
spacecraft will add another asteroid encounter to its 4-billion-mile journey.
On Nov. 1, 2023, Lucy will get a close-up view of a small main-belt asteroid to
conduct an engineering test of the spacecraft’s innovative asteroid-tracking
navigation system.
The Lucy mission is already breaking
records by planning to visit nine asteroids during its 12-year tour of the
Jupiter Trojan asteroids, which orbit the Sun at the same distance as Jupiter.
Originally, Lucy was not scheduled to get a close-up view of any asteroids
until 2025, when it will fly by the main belt asteroid (52246) Donaldjohanson.
However, the Lucy team identified a small, as-yet unnamed asteroid in the inner
main belt, designated (152830) 1999 VD57, as a potential new and useful target
for the Lucy spacecraft.
“There are millions of asteroids in the
main asteroid belt,” said Raphael Marschall, Lucy collaborator of the Nice
Observatory in France, who identified asteroid 1999 VD57 as an object of
special interest for Lucy. “I selected 500,000 asteroids with well-defined
orbits to see if Lucy might be traveling close enough to get a good look at any
of them, even from a distance. This asteroid really stood out. Lucy’s
trajectory as originally designed will take it within 40,000 miles of the
asteroid, at least three times closer than the next closest asteroid.”
As the NASA Lucy spacecraft travels through the inner edge of the main asteroid belt in the Fall of 2023, the spacecraft will fly by the small, as-of-yet unnamed, asteroid (152830) 1999 VD57. This graphic shows a top-down view of the Solar System indicating the spacecraft's trajectory shortly before the November 1 encounter. Credits: NASA's Goddard Space Flight Center
The Lucy team realized that, by adding a
small maneuver, the spacecraft would be able to get an even closer look at this
asteroid. So, on Jan. 24, the team officially added it to Lucy’s tour as an
engineering test of the spacecraft’s pioneering terminal tracking system. This
new system solves a long-standing problem for flyby missions: during a
spacecraft’s approach to an asteroid, it is quite difficult to determine
exactly how far the spacecraft is from the asteroid, and exactly which way to
point the cameras.
“In the past, most flyby missions have
accounted for this uncertainty by taking a lot of images of the region where
the asteroid might be, meaning low efficiency and lots of images of blank
space,” said Hal Levison, Lucy principal investigator from the Southwest
Research Institute Boulder, Colorado office. “Lucy will be the first flyby
mission to employ this innovative and complex system to automatically track the
asteroid during the encounter. This novel system will allow the team to take
many more images of the target.”
It turns out that 1999 VD57 provides an
excellent opportunity to validate this never-before-flown procedure. The
geometry of this encounter—particularly the angle that the spacecraft
approaches the asteroid relative to the Sun—is very similar to the mission’s
planned Trojan asteroid encounters. This allows the team to carry out a dress
rehearsal under similar conditions well in advance of the spacecraft’s main
scientific targets.
This asteroid was not identified as a
target earlier because it is extremely small. In fact, 1999 VD57, estimated to
be a mere 0.4 miles (700 m) in size, will be the smallest main belt asteroid
ever visited by a spacecraft. It is much more similar in size to the near-Earth
asteroids visited by recent NASA missions OSIRIS-REx and DART than to
previously visited main belt asteroids.
The Lucy team will carry out a series of
maneuvers starting in early May 2023 to place the spacecraft on a trajectory
that will pass approximately 280 miles (450 km) from this small asteroid.
Lucy’s principal investigator is based out of the Boulder, Colorado branch of Southwest Research Institute, headquartered in San Antonio, Texas. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin Space in Littleton, Colorado, built the spacecraft. Lucy is the 13th mission in NASA’s Discovery Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for the Science Mission Directorate at NASA Headquarters in Washington.
For more information about NASA’s Lucy
mission, visit: https://www.nasa.gov/lucy
Source: NASA’s Lucy Team Announces New Asteroid Target | NASA
No comments:
Post a Comment