Ryota Nakano

Auburn University | AU · Department of Aerospace Engineering

Asteroid (3200) Phaethon, a B-type asteroid, has been active during its perihelion passages. This asteroid is considered to be a source of the Geminid meteor stream. It is reported that this asteroid is spinning at a rotation period of $3.60 \ hr$ and has a top shape (an oblate body with an equatorial ridge) with a mean equatorial diameter of $6.25...

This paper presents an efficient indirect optimization method to solve time-and fuel-optimal asteroid landing trajectory design problems. The gravitational field of the target asteroid is approximated with two methods: 1) a simple two-body (point-mass) model, and 2) a high-fidelity polyhedral model. A homotopy approach, at the level of the gravity-...

NASA's Double Asteroid Redirection Test (DART) mission is the first full-scale planetary defense mission. The target is the binary asteroid (65803) Didymos, in which the smaller component Dimorphos (∼164 m equivalent diameter) orbits the larger component Didymos (∼780 m equivalent diameter). The DART spacecraft will impact Dimorphos, changing the s...

The Double Asteroid Redirection Test (DART) is the first planetary defense mission to demonstrate the kinetic deflection technique. The DART spacecraft will collide with the asteroid Dimorphos, the smaller component of the binary asteroid system (65803) Didymos. The DART impact will excavate surface/subsurface materials of Dimorphos, leading to the...

NASA's Double Asteroid Redirection Test (DART) spacecraft is planned to impact the natural satellite of (65803) Didymos, Dimorphos, around 23:14 UTC on 26 September 2022, causing a reduction in its orbital period that will be measurable with ground-based observations. This test of kinetic impactor technology will provide the first estimate of the m...

The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on September 26, 2022 as a planetary defense test ¹ . DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planetary defens...

Synchronous binary asteroids can experience libration about their tidally-locked equilibrium, which will result in energy dissipation. This is an important topic to the Asteroid Impact and Deflection Assessment, where excitation caused by the DART kinetic impact in the Didymos binary asteroid system may be reduced through dissipation before Hera ar...

NASA's Double Asteroid Redirection Test (DART) is the first full-scale test of an asteroid deflection technology. Results from the hypervelocity kinetic impact and Earth-based observations, coupled with LICIACube and the later Hera mission, will result in measurement of the momentum transfer efficiency accurate to ∼10% and characterization of the D...

Synchronous binary asteroids can experience libration about their tidally-locked equilibrium, which will result in energy dissipation. This is an important topic to the Asteroid Impact and Deflection Assessment, where excitation caused by the DART kinetic impact in the Didymos binary asteroid system may be reduced through dissipation before Hera ar...

NASA's Double Asteroid Redirection Test (DART) is the first full-scale test of an asteroid deflection technology. Results from the hypervelocity kinetic impact and Earth-based observations, coupled with LICIACube and the later Hera mission, will result in measurement of the momentum transfer efficiency accurate to ~10% and characterization of the D...

We introduce a new BYORP model which simultaneously simulates the highly coupled mutual gravitational interaction of the non-spherical bodies, known as the full two-body problem (F2BP), and the three-dimensional (3D) thermophysical condition of the secondary. This model employs Finite Element Modeling approaches. Using the model, we investigate t...

Active asteroid (6478) Gault sheds mass independent of location along its orbit. Rotational instability is considered to induce the observed activities. If this is the case, because Gault’s breakup event has not been detected, surface failure is likely, implying that its surface materials are constantly ejected while its major body remains intact....

Active asteroid (6478) Gault sheds mass independent of location along its orbit. Rotational instability is considered to induce the observed activities. If this is the case, because Gaults breakup event has not been detected, surface failure is likely, implying its surface materials are constantly ejected while its major body remains intact. Given...

NASA/Double Asteroid Redirection Test (DART) is the first deep exploration mission that explores the capability of kinetic impact asteroid deflection for purely scientific purposes by targeting the binary asteroid 65803 Didymos, where a smaller secondary (Dimorphos) orbits a larger, fast rotating, top-shaped primary (Didymos). After the spacecraft...

Proximity observations by OSIRIS-REx and Hayabusa2 provided clues on the shape evolution processes of the target asteroids, (101955) Bennu and (162173) Ryugu. Their oblate shapes with equatorial ridges, or the so-called top shapes, may have evolved due to their rotational conditions at present and in the past. Different shape evolution scenarios we...

Proximity observations by OSIRIS-REx and Hayabusa2 provided clues on the shape evolution processes of the target asteroids, (101955) Bennu and (162173) Ryugu. Their oblate shapes with equatorial ridges, or the so-called top shapes, may have evolved due to their rotational conditions at present and in the past. Different shape evolution scenarios we...

Asteroid (3200) Phaethon, a B-type asteroid, has been active during its perihelion passages. This asteroid is considered to be a source of the Geminid meteor stream. It is reported that this asteroid is spinning at a rotation period of $3.60 \ hr$ and has a top shape (an oblate body with an equatorial ridge) with a mean equatorial diameter of $6.25...