Planetary Defense Test: NASA to intentionally crash a spacecraft into an asteroid

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Planetary Defense Test: NASA to intentionally crash a spacecraft into an asteroid

Many last tests have been carried out and rehearsals are taking place for NASA’s Double Asteroid Redirection Test (DART), which is slated to launch on November 23, 2021.

Asteroid Dimorphos, which circles a bigger asteroid named Didymos, is the target of DART’s first planetary defense test mission. DART will deliberately crash into the asteroid to alter its orbit.

Asteroid DART’s kinetic impact will demonstrate that a spacecraft can autonomously cruise to an asteroid and kinetically hit it, even if neither asteroid threatens Earth. The expedition will next use Earth-based telescopes to evaluate the consequences of the collision on the asteroid system, which will help us better prepare for a true asteroid danger if one is ever identified.

“DART will be the first demonstration of the ‘kinetic impactor’ technique in which a spacecraft deliberately collides with a known asteroid at high speed to change the asteroid’s motion in space,” said Lindley Johnson, NASA’s Planetary Defense Officer. “This technique is thought to be the most technologically mature approach for mitigating a potentially hazardous asteroid, and it will help planetary defense experts refine asteroid kinetic impactor computer models, giving insight into how we could deflect potentially dangerous near-Earth objects in the future.”

DART packed and ready to move to SpaceX. DART team members stand outside Astrotech Space Operations processing facility with the shipment container holding the DART spacecraft. DART moved to SpaceX’s payload processing facility late last month. Credit: NASA/Johns Hopkins APL/Ed Whitman

The engineers at DART worked for more than a year and a half, following rigorous health and safety regulations, to transform DART from a collection of pieces to a completed spaceship. 

NASA’s NEXT-C ion propulsion system was installed on the spacecraft, which was designed to improve performance and fuel efficiency for deep-space missions. Engineers also installed a flat, slotted high-gain antenna to ensure efficient communication between Earth and the spacecraft, which will be used to test a variety of technologies.

Summer and early September were spent assembling the spacecraft’s onboard camera DRACO (its sole instrument), its two roll-out solar arrays, which can each extend to 28 feet in length, and the Italian Space Agency’s miniature satellite LICIACube, which will be used to photograph the kinetic impact of DART and its immediate aftereffects.

“It’s a miracle what this team has accomplished, with all of the obstacles in the way like COVID and the development of so many new technologies,” said Elena Adams, DART mission systems engineer at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. “But the reason why we succeeded so far is because our team is excited, extremely sharp, and they genuinely want to show that if an asteroid was coming toward Earth, we could prevent a catastrophe.”

After a long journey across the nation, the spacecraft finally landed at Vandenberg Space Force Base (VSFB) in Lompoc, California, in early October.

Team members have been hard at work preparing the spacecraft for flight, testing its mechanisms and electrical system, wrapping final parts in multilayer insulation blankets, and practicing launch sequences from both the launch site and the mission operations center at APL. 

On October 26, DART embarked on a journey to the SpaceX Payload Processing Facility on VSFB. Approximately 110 pounds (50 kilogrammes) of hydrazine propellant for spacecraft maneuvers and attitude control was added to DART’s fuel tank two days after the crew obtained the go-ahead.

In addition, DART transports around 130 pounds (60 kilogrammes) of xenon for use in the NEXT-C ion engine. Engineers completed the loading of the xenon before the spacecraft left APL in late October.

In the next weeks, beginning on November 10, engineers will “mate” the spacecraft to the adapter that will sit atop the SpaceX Falcon 9 rocket. The rocket will roll out of the hangar and onto the launch pad at Space Launch Complex 4 East (SLC-4E), where it will blast the spacecraft into orbit and begin DART’s voyage to the Didymos system.

“I’m both amazed and grateful that DART has gone from a twinkle in the eye to a spacecraft in final preparation for launch within 11 years,” said Andy Cheng, DART investigation team lead at APL and the one who came up with the idea of DART. “What made it possible was a great team that overcame all the challenges of building a spacecraft to do something never done before.”

The first launch opportunity for DART is slated for November 23 at 10:20 p.m. Pacific Standard Time (PST). If weather or other issues prohibit the team from launching on the first night, they will get an another chance to launch on the following day, weather permitting. If required, more launch attempts will be made until February 2022, at the earliest.