The Double Asteroid Redirection Test (DART) is a National Aeronautics and Space Administration–European Space Agency collaborative mission to test the feasibility of defending Earth from a catastrophic asteroid impact by using a spacecraft to deflect the asteroid away from the planet. Launched on Nov. 23, 2021, the DART spacecraft will intercept the binary asteroid 65803 Didymos in late September or early October 2022, colliding (nearly) head-on to modify its motion measurably.

1.
eoPortal
, “
DART (Double Asteroid Redirection Test) mission
,” https://directory.eoportal.org/web/eoportal/satellite-missions/d/dart-asteroid.
2.
A. F.
Cheng
et al, “
Asteroid impact & deflection assessment mission: Kinetic impactor
,”
Planet. Space Sci.
121
,
27
35
(
2016
). Note that these authors assume an impactor mass >300 kg and an impact velocity 27.5° from the plane of the asteroid orbit. Other sources, such as Ref. 1 above, use different assumptions.
3.
P.
Pravec
et al, “
Photometric survey of binary near-Earth asteroids
,”
Icarus
181
,
63
93
(
2006
).
4.
Solar System Dynamics, NASA Jet Propulsion Laboratory, California Institute of Technology, “
Horizons system
,” https://ssd.jpl.nasa.gov/horizons/app.html#/. This website offers an easy-to-use application for calculating the position and velocity of solar system objects relative to the Sun, Earth, or other bodies.
5.
European Space Agency
, “
Didymos: Facts & figures
,” https://www.esa.int/Safety_Security/Hera/Didymos_facts_figures.
6.
This derivation is included because it is not usually presented in traditional introductory texts.
7.
Readers can access the supplementary materials at https://doi.org/10.1119/5.0085522, under the Supplemental tab.
8.
A. F.
Cheng
et al, “
AIDA DART asteroid deflection test: Planetary defense and science objectives
,”
Planet. Space Sci.
157
(
2018
)
104
115
.
9.
E. M.
Edlund
, “
Interception and rendezvous: An intuition-building approach to orbital dynamics
,”
Am. J. Phys.
89
,
559
566
(June
2021
). This article elegantly describes the perturbation of a spacecraft’s initially circular orbit due to a short thruster burn. The author derives the parameters of the resulting elliptical orbit for all orientations of Δv relative to the initial velocity.
10.
Readers can access the Appendix at https://doi.org/10.1119/5.0085522, under the Supplemental tab.

Supplementary Material

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