DART

A NEW ERA FOR PLANETARY DEFENSE BEGINS
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Until recently, the idea of catastrophic asteroids colliding with Earth has been more in tune with the plots of blockbuster disaster movies than with serious science. However, as humanity peers deeper into the universe, these threats are becoming more of a reality, and planetary defense is taking center stage.

Through Earth observation and survey missions, we have become more aware of threats from near-Earth objects (NEO): asteroids and comets that orbit the Sun like the planets, but with orbits that can bring them within 30 million miles of Earth’s orbit. Although no known asteroid larger than 140 meters in size has a significant chance to hit Earth for the next 100 years, only about 40 percent of those asteroids have been found to date.

The number of small asteroids we know of continues to increase at an accelerating rate. It is not that the threat from asteroids is increasing. Rather, humanity is becoming increasingly aware of the existing threat posed by asteroids.”

Luckily, leaders are taking action. In 1998, Congress directed NASA to find 90 percent of the NEOs 1 kilometer or more in diameter within 10 years and in 2005, Congress directed NASA to find 90 percent of NEOs 140 meters or more in diameter within 15 years. Both the Obama and Trump administrations issued NEO preparedness strategies and action plans and Congress has increased funding for NEO observations and surveillance. 

NASA is addressing the NEO impact hazard, in part, through planetary defense, “applied planetary science” that involves all the capabilities needed to detect the possibility and warn of potential asteroid or comet impacts with Earth, and then either prevent them or mitigate their possible effects. In 2016, NASA established the Planetary Defense Coordination Office (PDCO) to lead these efforts. With a clear mission and enthusiastic backing from governments and agencies, the PDCO is embarking on its first groundbreaking mission for planetary defense.

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DART

A First for Planetary Defense
Bringing planetary defense to the forefront is NASA’s Double Asteroid Redirection Test (DART), the first mission to test planetary defense technology. The only mission of its kind, DART is focused solely on testing techniques and technologies that could be used to enable future planetary defense missions and protect Earth from a dangerous impact. DART is NASA’s contribution to the Asteroid Impact & Deflection Assessment (AIDA) mission, an international cooperation between NASA and the European Space Agency (ESA). The mission will be invaluable to our understanding of dangerous asteroids and how we can protect the planet from these threats using new, advanced technology.

DART will launch from Vandenberg Space Force Base in California no earlier than Wednesday, November 24, 2021, at 1:20 a.m. EST (10:20 p.m. PST Tuesday, Nov. 23). The spacecraft will do something no other spacecraft has done before: it will crash itself into an asteroid in an effort to change its trajectory. This is the kinetic impactor method of deflecting an asteroid, and it involves sending a spacecraft into the path of an approaching NEO to deflect the asteroid into a different trajectory, steering it away from the Earth.

The DART mission is also testing critical, enabling technologies for future missions, including NASA’s Evolutionary Xenon Thruster-Commercial (NEXT-C) Ion Propulsion Engine, the SMART Nav system, and the Didymos Reconnaissance and Asteroid Camera for OpNav (DRACO).

Directed by NASA to the Johns Hopkins Applied Physics Laboratory (APL) with support from several NASA centers, DART will profoundly advance our ability to protect Earth from potentially catastrophic impacts and deepen our understanding of the solar system.

Redwire is proud to be a part of the DART mission by providing advanced sensors and components for this first-of-its-kind spacecraft, and for its work on previous missions to explore asteroids and other NEOs, which have laid the groundwork for the critical planetary defense work happening today.

A Complex Mission

DART’s target is a binary asteroid system made up of the asteroid Didymos and its small moonlet, Dimoprhos.

DART will achieve the kinetic impact deflection by crashing itself into Dimorphos at a speed of approximately four miles per second using DRACO and the SMART Nav autonomous navigation system. The goal of the mission is to determine how much the impact alters the moonlet’s velocity in space by measuring the change in its orbit around Didymos.

Credits: Naidu et al., AIDA Workshop, 2016

Above: Simulated image of the Didymos system.

The collision will change the speed of Dimorphos in its orbit by a fraction of one percent, changing the orbital period of the moonlet by several minutes. This is enough to be observed and measured using telescopes on Earth. The DART spacecraft will be accompanied by a small satellite, the Light Italian CubeSat for Imaging Asteroids (LICIACube), which will document the effects of the impact.

While Dimorphos is not a threat to Earth, it is an ideal target for the mission. Its size is similar to that size of an asteroid that might be a threat to Earth. Its proximity to Earth in 2022 also makes it possible for the effects of the collision to be observed from telescopes on Earth.

Redwire Technology

Enabling DART

Digital Sun Sensors + Electronics Processing for Navigation

The Redwire technology on board the spacecraft is providing critical navigation and power-generation capabilities that will enable the DART to accomplish its mission.

Image Credit: NASA/APL

Roll-Out Solar Arrays (ROSA)

Digital Sun Sensors + Electronics Processing for Navigation

Credit: Johns Hopkins APL

Redwire is also providing five digital sun sensors and an electronics processing unit to enable navigation of the DART spacecraft millions of miles to its target. The Digital Sun Sensor is a two-axis digital sun sensor system. DART’s Digital Sun Sensors will be used for attitude control and fail-safe recovery throughout the mission. The sun sensor configuration is unique on the DART mission because there are five sensors on the spacecraft. The field of view (FOV) for each sensor head is ±64° x ±64°. By placing five of these sensors about the spacecraft, at least one of the sensor heads is guaranteed to have the Sun in its FOV. The combined FOV of all five sensor heads is the complete celestial sphere (4π sr).

In addition to the sun sensors, DART also includes a purpose-built electronics processing unit. The electronics processing unit works by receiving the solar cell signals from the five sensor heads and converting those signals into a digital format that is sent to the autonomous SMART Nav system, the spacecraft’s onboard computer. The data output of the electronics is of a specific universal asynchronous receiver-transmitter protocol that is implemented to directly interface with SMART Nav.

Roll-Out Solar Arrays for Power

Credit: Johns Hopkins APL

DART’s electronic propulsion unit will be powered by Redwire’s patented Roll-Out Solar Array (ROSA), a high-performance, lightweight, compact solar array solution. The arrays will produce more than 6.5 Kw of power, providing 100% of the power for the spacecraft. They will also feature Redwire’s Flexible Array Concentrator Technology (FACT) Solar Power Modules, which use high efficiency SolAero Inverted Metamorphic Module 4J Photovoltaic solar cells, as a Transformational Solar Array demonstration. DART marks the first time ROSA will operate in deep space. A modular version of ROSA was recently deployed on the International Space Station.

PAST MISSONS

MISSIONS THAT PAVED THE WAY FOR DART

While the DART mission is the first planetary defense mission, our knowledge and understanding of asteroids and other NEOs is built on the discoveries made on previous missions. These missions provided important science, critical information, and proof-of-concept needed for today’s planetary defense work.

As a trusted supplier of advanced sensors and components for nearly every NASA planetary science mission, Redwire technology has enabled many of these earlier missions to study asteroids and other NEOs.

FUTURE MISSONS

PLANETARY DEFENSE MISSIONS BEYOND DART

The DART mission is just the beginning for planetary defense-focused missions. Upcoming missions will continue planetary defense work, not only to observe and find NEOs, but also to test mitigation methods and new technologies.

BEYOND PLANETARY DEFENSE

While the DART mission is a pivotal step for advancing planetary defense science and protecting Earth, it embodies much more. With DART, humanity continues to make the unknown known and expand our understanding of Earth’s place in the solar system.

As the DART spacecraft travels millions of miles to Didymos, it takes with it technology that represents the best of humanity’s ingenuity, curiosity and never-ending spirit of discovery.

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