Perched atop a stand in the middle of a high-ceilinged clean room, DART is beginning to look like the intrepid spacecraft that will aim itself directly into an asteroid next fall. With the addition of its compact Roll-Out Solar Arrays (ROSA) coiled into two gold cylinders that flank the sides of the spacecraft, and its less visible but still integral imager, the Didymos Reconnaissance and Asteroid Camera for Optical (DRACO) navigation tucked safely beneath its panels, the spacecraft is close to fully integrated.
This mix of current and new technologies, some of which it will demonstrate for the first time, will see DART through its 10-month journey toward its asteroid target.
The recently installed Roll-Out Solar Arrays (ROSA) and Didymos Reconnaissance and Asteroid Camera for Optical (DRACO) navigation are two critical technologies that will enable the DART spacecraft to navigate through space and effectively reach the Didymos asteroid system. Credits: NASA/Johns Hopkins APL/Ed Whitman
NASA's DART, the Double Asteroid
Redirection Test, is a carefully planned demonstration that will help
determine if kinetic impactor technology—flying a spacecraft directly into a
small Solar System body at speeds of about 15,000 miles per hour with the
intention of changing its course—can serve as a reliable method of asteroid
deflection in the event that such a hazard ever heads for the Earth. NASA is
constantly monitoring the skies and has already identified nearly 40% of
potentially hazardous asteroids larger than 140 meters (459 feet) in size, none
of which are slated to impact our planet, including the binary system selected
for this first-ever deflection test.
But to prove that our planet can expect the unexpected, the DART mission
will set out to push an asteroid and safely change its motion in space. For the
last two years, the spacecraft destined for this undertaking has been developed
and built at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland.
APL, which leads the mission for NASA, is now putting the finishing touches on
the spacecraft.
The recently installed ROSA and DRACO are two critical technologies that
will enable the spacecraft to navigate through space and reach the Didymos
asteroid system. The flexible and rollable modular “wings” are lighter, more
compact and stiffer than traditional solar arrays despite their size; in
space, each array will slowly unfurl to reach 28 feet in length—about the size
of a bus. The technology was first successfully tested in 2017 on the
International Space Station (ISS), and newer versions were installed this past
June for full-time use on the ISS. DART will be the first spacecraft to
fly the new arrays, paving the way for their use on future missions. Redwire developed
the technology at their Goleta, California facility and delivered ROSA to
APL in May and worked closely with the APL team in the following weeks to
carefully install them onto the spacecraft.
And while DRACO is not entirely
“new" (it was inspired by the New Horizons LORRI camera), this
upgraded imager will be the sole instrument onboard the
spacecraft. Combined with the autonomous navigation software
SMART Nav (Small-body Maneuvering Autonomous
Real-Time Navigation), it will play the key role in helping DART navigate
through space and identify the correct asteroid to aim itself toward.
The flexible and rollable “wings” are lighter and more compact than traditional solar arrays despite their size; in space, each array will slowly unfurl to reach 28 feet in length, about the size of a bus. Credits: NASA/Johns Hopkins APL/Ed Whitman
“Traditional navigation techniques would only get DART somewhere
within about 9 miles of the target asteroid,” said APL’s Zach Fletcher,
DRACO lead engineer. “To achieve our mission objectives, we need to remove the
rest of that error via on-board optical navigation. DRACO starts supplying
images to DART's on-board autonomous navigation system more than 50,000 miles from
its target, four hours before the impact and is key to DART achieving a kinetic
impact on Dimorphos."
The images DRACO returns of the target asteroid Dimorphos, including the
last-second glimpse of its own impact site on the asteroid, will be crucial
toward analyzing the results of the DART test and understanding how the
asteroid was affected.
DART has been through its paces in the last several months, enduring a
battery of environmental testing and
analysis as the final pieces of the craft
started coming together. Likewise, the SMART Nav software has seen its fair
share of testing so the team can confidently relinquish the reins on DART in
the final hours before it collides into Dimorphos. With DRACO and ROSA on
board, the DART spacecraft completed vibration testing in late July to ensure
that all of its hardware is secure and ready for the rigors of launch.
The Light Italian CubeSat for Imaging of Asteroids, or LICIACube,
contributed by the Italian Space Agency, will be one of the final components to
hitch a ride on DART before it is delivered to the launch site this October.
LICIACube will deploy roughly five days prior to the DART impact and capture
images of the spacecraft's final moments, the resulting ejecta plume, and the
back side of the asteroid that DRACO will never see.
"DART is the result of years of work by a dedicated team
and partners who have overcome unique challenges to accomplish
firsts in both technology development and planetary defense," said DART
mechanical engineer Betsy Congdon, who led the team during the installation.
“With the successful installation and testing of two critical technologies,
DRACO and ROSA, we're very confident that DART is ready to complete its final
system testing and reviews before shipping to the launch site."
This November, the spacecraft will launch on a SpaceX Falcon 9 rocket from
Vandenberg Space Force Base near Lompoc, California. In the fall of 2022, DART
will have its sights set for Dimorphos, the smaller moonlet orbiting the larger
Didymos asteroid. Its collision with Dimorphos will change the speed of the
moonlet’s orbit around the main body by several minutes. And despite being
approximately 6.8 million miles away from Earth at the time of impact, the
asteroid system will be visible to ground-based telescopes, which scientists
will use to determine the exact change in the orbital period.
DART is directed by NASA's Planetary Defense Coordination Office to APL with support from several NASA centers: the Jet Propulsion Laboratory, Goddard Space Flight Center, Johnson Space Center, Glenn Research Center and Langley Research Center.
To learn more about the DART mission, visit: https://www.nasa.gov/planetarydefense/dart and dart.jhuapl.edu
To learn more about NASA's Planetary Defense Coordination Office, visit: https://www.nasa.gov/planetarydefense
Source: DART
Gets Its Wings with Innovative Solar Array Technology and Camera | NASA
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