Hitting the Dimorphos’s eye — DART Mission ft. NASA, SpaceX & JHU APL
“The Solar System has been hurling asteroids toward Earth for billions of years. In 2022, we begin to make it stop.”
Dart? Huh?
DART — Double Asteroid Redirection Test is NASA’s first mission to demonstrate the kinetic impactor technology, impacting an Asteroid to change its speed and path.
Kinetic Impactor technology — Transferring the kinetic energy of one body onto the other is what a kinetic impactor does. It is the same kind of tech that one would use if a PHA(Potentially Hazardous Asteroid) is on a collision course with the Earth, and you wanted to deflect it to keep that from happening.
Spacecraft impacts the asteroid with its enormous kinetic energy, which deflects it, changing its future path.
Date period of Impact — September 26 — October 1, 2022
The choice for the impact date is in September 2022 because that’s when the distance between the Earth and the Didymos Asteroid system is minimized so as to get the highest quality data from the earth-based telescopes. It will still be roughly 11 million kilometers from the Earth at the time of the DART impact, but the earth-based telescopes will contribute towards the worldwide observing campaign to determine the effect of DART’s impact.
Why are we using Earth-based telescopes for analyzing data?
The Dart spacecraft will come over towards the Didymos Asteroid system speeding in at over 6km/s. With that amount of kinetic energy, when it impacts the moonlet asteroid (Dimorphos), it will get destroyed, so measuring how much deflection it caused can’t be done by the spacecraft itself.
Earth-based telescopes will see how much the path is changed, analyzing the critical data and storing it.
These telescopes will also do all other crucial measurements like impact velocity and stuff, so it’s a very cost-effective way to do this focused first demonstration test.
Why Didymos Asteroid system?
Is the Didymos asteroid system a threat to Earth in the near future?
If yes, why are we trying a technology on a mission that has never been practically tested earlier? If the spacecraft fails to impact, isn’t that a threat to terrestrial life?
Absolutely not!
DART’s target is the binary asteroid system Didymos, meaning “twins” in Greek which explains the term Double in the mission’s name.
Didymos is not on a collision course with the Earth; therefore, it poses no actual threat to the planet, so it serves as an ideal candidate to perform this first test to demonstrate Kinetic impactor technology.
What’s a binary asteroid system?
Two asteroids orbiting their common barycenter, i.e., their center of mass, form a binary asteroid system.
Didymos is also composed of 2 Asteroids -
1. Didymos A(Larger) — 780 meters in diameter
2. Dimorphos or Didymos B (Smaller moonlet) — 160 meters in diameter, going around the primary asteroid every 12 hours.
The main target of DART’s spacecraft is the moonlet asteroid of the system — Dimorphos
The collision of Dimorphos with spacecraft will be head-on, shortening its orbital period around Didymos by several minutes.
If all goes well, it is planned that the orbital period may be reduced from 12 hours to up to 10 minutes.
Can after the impact, the Didymos’s orbit intersect Earth’s?
Renowned Engineers at JHU APL (Johns Hopkins University Applied Physics Laboratory), which is leading and building this mission for NASA, have carefully formulated that the impulse the spacecraft will deliver to the Didymos system is low and cannot disrupt the asteroid.
With that low impulse, Didymos’s orbit cannot intersect Earth’s at any point.
Payload and Takeaway Technologies
Payload — DRACO
The Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) is a high-resolution imager inspired by the Long-Range Reconnaissance Imager on the New Horizons spacecraft.
The main job of DRACO is to snap images of the asteroid targets, which will provide essential data for analysis and interpretation of the kinetic impact test results; other than that, it will also support the navigation system of the spacecraft.
The images acquired by DRACO before the kinetic impact will be streamed back to Earth in real-time. In its final moments, DRACO will help characterize the impact site by providing high-resolution, scientific images of the surface of Dimorphos.
GNC and SMART Nav
The primary challenge for the spacecraft is to collide head-on with dimorphous — moonlet asteroid of the Didymos system.
JHU APL, as a part of the guidance, navigation, and control (GNC), developed algorithms called Small-body Maneuvering Autonomous Real-Time Navigation (SMART Nav). Using the images snapped by DRACO, this intelligent navigation system will help DART’s spacecraft distinguish the size and locate the smaller one of the two asteroids.
SMART Nav is another new technology that is debuting in this mission.
LICIACube
Contributed by the Italian space agency (Agenzia Spaziale Italiana (ASI)), DART will also carry a CubeSat named LICIACube(Light Italian CubeSat for Imaging of Asteroids). It will be deployed 10 days before the impact on the moonlet asteroid. LICIACube will capture images of the DART impact, the resulting ejecta cloud, and potentially a glimpse of the impact crater on the surface of Dimorphos. LICIACube has two instruments: LEIA (LICIACube Explorer Imaging for Asteroid), a narrow field panchromatic camera to acquire long distances with a high spatial resolution, and LUKE (LICIACube Unit Key Explorer), a wide field RGB camera, allowing a multicolor analysis of the asteroidal environment.
Planetary defense? Is it indispensable?
“Comets and asteroids can strike out of nowhere.”
Fragments of rocks and dust collide with Earth all the time, but we see no devastation; why?
Because most of them are harmless and burn up in Earth’s atmosphere but not all.
Some of them make through, causing local damage or sometimes massive destruction.
The Chelyabinsk event — a massive asteroid hit the Chelyabinsk city in Russia in 2013, causing a lot of damage.
The shockwaves released 20 to 30 times more energy than a WWII atomic bomb.
When they enter the Earth’s orbit, these Near-Earth Objects (NEO), like asteroids, comets, etc., can become hazardous.
Astronomers estimate that approximately 25,000 near-Earth asteroids close to 500 feet (140 meters) or larger in size are big enough to cause regional devastation if they hit Earth. This underscores the need to discover and track near-Earth objects and perform real-world tests of potential asteroid deflection.
Planetary defense is “applied planetary science” to address the NEO impact hazard.
Does DART fit in?
DART’s primary focus is to impact the NEO’s of the space, which are Potentially Hazardous and change their collision course using its Kinetic impactor technology. It allows a deflection demonstration on an asteroid of the appropriate size by changing its orbital period by ~1% about the more giant asteroid.
It addresses the attenuated component of the planetary defense efforts which have been made in the past.
DART is NASA’s first spacecraft mission developed to achieve planetary defense objectives and the first mission being flown by NASA’s newly formed PDCO (Planetary Defence Coordination Office)
“This incredible mission will use innovative technologies as it autonomously navigates toward the Didymos system, and it is an integral part of NASA’s planetary defense program.”
— Andrea Riley, DART program executive, NASA Headquarters.
With that, Let’s see if this DART hits the Bull’s eye!
