# Internet of Spacecraft for Multi-Planetary Defense and Prosperity
## 1 Introduction
Figure 4: (**a**) Illustration of an artist’s concept of Cassini–Huygens’ orbit insertion around Saturn [5]; and (**b**) artist’s illustration of the Rosetta orbiter deploying the Philae lander to comet 67P/Churyumov–Gerasimenko [6]. Figure 3: (**a**) Hubble as seen from the Space Shuttle _Discovery_ during its second servicing mission [4]; and (**b**) the James Webb Space Telescope full-scale model assembled on the lawn at Goddard Space Flight Center with the JWST team [14]. In addition to the planetary probe, the comet probe is another type of spacecraft, and one representative is the Rosetta spacecraft designed and launched in March 2004 by ESA to study comet 67P [18]. It was the first spacecraft to orbit a comet nucleus and the first spacecraft to be in close proximity of a frozen comet toward a direction warmed by the Sun. The Rosetta orbiter dispatched the Philae lander for the first controlled touchdown on a comet nucleus. An illustration is shown in Figure 4b. The Philae's instruments obtained the first images from a comet's surface and made the first on-site analysis of its composition. On 30 September 2016, Rosetta was guided down to the comet's surface, and the mission ended on impact [19, 20]. Moreover, on 24 November 2021, SpaceX Falcon 9 successfully launched the Double Asteroid Redirection Test (DART) spacecraft to test a method of planetary defense against near-Earth objects (NEOs) [7]. The DART spacecraft hosts no scientific payload, but it does include sensors and a navigation system and plans to arrive at 65,803 Didymos, a sub-kilometer asteroid and synchronous binary system classified as a potentially hazardous asteroid. Then, DART is set to crash into the asteroid system deliberately. The collision is scheduled in September/October 2022 when the impact of the 500 kg DART will target the center of Dimorphos, which is the minor-planet moon of 65,803 Didymos. The ASI's secondary spacecraft, called LICIACube (Light Italian CubeSat for Imaging of Asteroids), a small CubeSat, will ride on DART and then separate 10 days before impact to acquire images of the impact and ejecta as it drifts past the asteroid. The effects of the impact of DART will also be monitored from ground-based telescopes and radar. In addition, a mission to 16-Psyche, which is a massive M-type asteroid with a mean diameter of 220 \(\pm\) 3 km [21] that orbits the Sun in the main asteroid belt, was proposed to NASA in 2014. The concept of a robotic Psyche orbiter was proposed by a team led by [PERSON] [22], at Arizona State University. They proposed to use the spacecraft to orbit Psyche for 20 months and study its topography, surface features, gravity, magnetism, and other characteristics since Pysche is the only metallic core-like body discovered so far. The mission's launch date was moved up to July 2022 from the original date in October 2023, targeting a more efficient trajectory with a Mars gravity assist in 2023 and arriving in 2026. On 28 February 2020, SpaceX won a USD 117 million contract from NASA to launch the Psyche spacecraft in July 2022. Apart from the representative missions, either accomplished or ongoing, mentioned above, there are many other spacecraft and space missions under construction or planned. Generally, exploring and discovering more unknowns of the universe is one of the most fundamental drives of the space projects, which stems from the curiosity rooted in the human species. Moreover, the technical advances in the related areas of the space industry reduce the cost and enable some previous theories to become practical and commercial plans such as space tourism and extraterrestrial colonization. Nevertheless, along with the exciting opportunities in the space age come unprecedented challenges, some of which may even pose potential extinction-level disasters to the human species. In this article, we will continue to investigate critical space missions/projects focusing on space colonization, which will be followed by the review and analysis of the asteroid threat and planetary defense.