The LICIACube legacy

Introduction: The Light Italian Cubesat for Imaging of Asteroids (LICIACube) [1] is a 6U CubeSat developed for the Italian Space Agency (ASI).  LICIACube was carried  by NASA’s Double Asteroid Redirection Test (DART) spacecraft and was deployed 15 days in advance of DART’s impact with the asteroid Dimorphos  [2] to acquire images of the event and its effects. During its post-impact flyby, LICIACube achieved a minimum distance of approximately 58 km from Dimorphos and returned more than 400 scientific images, obtaining a unique view of the event [3]. 

The DART/LICIACube mission: The Double Asteroid Redirection Test (DART was launched on 24 November 2021 to perform the first test of a planetary defence mitigation technology, redirecting the asteroid Dimorphos, the small satellite of the binary Near Earth Asteroid (NEA) (65803) Didymos [4], via a kinetic impact. During the 9.5-month cruise, LICIACube was hosted on the DART spacecraft. On 11 September 2022, fifteen days before DART’s kinetic impact, LICIACube was released and autonomously continued its track toward the binary asteroid system. LICIACube was equipped with two different cameras, LICIACube Explorer Imaging for Asteroid (LEIA) and LICIACube Unit Key Explorer (LUKE) [1]. The science phase started 71 seconds before the nominal impact time, when LICIACube was about 1400 km from Dimorphos. The science phase of LUKE started 29 seconds after the impact, acquiring triplets of images with different exposure times. LICIACube followed the target and the evolution of the system up to 320 seconds after the impact. The spacecraft’s Closest Approach (CA) occurred 167 s after the impact.

The LICIACube images: LEIA images testified the DART impact by an increase in the luminosity of the target, while LUKE images revealed that the DART impact into Dimorphos generated a cone of ejected material with a large aperture angle [3]. In the LICIACube viewing geometry, the produced effects were clearly seen in both pre-CA and post-CA LUKE images (Fig. 1). The ejecta plume shows a complex and inhomogeneous structure, characterised by filaments, dust grains, and single or clustered boulders, providing insights into the properties of the ejecta, as well as the nature of Dimorphos. Measurements from the LICIACube images constrain the asteroid shape [5], and the 3D shape of the cone plume [6]. Moreover, they feed into the calculations of the momentum transferred to Dimorphos by DART’s kinetic impact [7]. The accomplishments of LICIACube demonstrated the compelling potential for future deep-space CubeSats.

Figure 1. Images obtained by LUKE pre-CA and post-CA (Credits: ASI/NASA)

 

Acknowledgments: The LICIACube team acknowledges financial support from Agenzia Spa-ziale Italiana (ASI, contract No. 2019-31-HH.0 CUP F84I190012600). 
References: [1] Dotto E., et al. (2021) PSS 199, id. 105185. [2] Daly R.T., et al. (2023) Nature 616 (7957), 443. [3] Dotto E., et al. (2024) Nature 627, 505. [4] Rivkin A.S., et al. (2021) PSJ 2(5), id.173. [5] Zinzi A., et al. (2023) PSJ 5, id.103. [6] De-shapriya J.D.P., et al. (2023) PSJ 4 id.231. [7] Cheng A.F., et al. (2023) Nature, 616(7957), 457.