# Internet of Spacecraft for Multi-Planetary Defense and Prosperity
## 3 Space Threats and Planetary Defense History
### Planetary Defense: When and How It Started
#### 3.2.2 Organization and Projects  
On the other hand, in June 2015, NASA and the National Nuclear Security Administration of the U.S. Department of Energy officially formed joint cooperation [98]. Then in January 2016, NASA officially announced the establishment of the Planetary Defense Coordination Office (PDCO) which aimed at identifying, tracking, and warning about potentially hazardous NEOs that are larger than 30-50 m in diameter and coordinating an effective emergency response, studying and developing mitigation technologies and techniques [99]. PDCO has been involved in several key NASA missions, namely OSIRIS-REx, NEOWISE, NEO Surveyor, and DART which has been mentioned earlier.  
OSIRIS-REx, which represents Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer, is a mission operated by NASA to study asteroids and the solar system study and obtain a sample of at least 60 g from an asteroid [100]. OSIRIS-REx was launched in September 2016 and rendezvoused with the asteroid 101955 Bennu in December 2018 [101]. In October 2020, it successfully touched down on Bennu and collected a sample with a mass of more than 60 g and is expected to return to Earth in September 2023 [102].  
Moreover, NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) is a transferred and renamed mission re-activated from the NASA infrared astronomy space telescope in the Explorer program, WISE (Wide-field Infrared Survey Explorer) [103, 104]. WISE was launched in December 2009 and placed in hibernation mode in February 2011 when it had already discovered thousands of minor planets, numerous star clusters, and Earth's first Trojan asteroid [105]. Since the reboot of NEOWISE, NASA has been working with the Jet Propulsion Laboratory to investigate NEO threat scenarios and expects to find suitable solutions to mitigate the impact.  
Last but not least, the NEO Surveyor, which was formerly called the Near-Earth Object Camera (NEOCam) and then the NEO Surveillance Mission, is also a space-based infrared telescope intended to survey the solar system for potentially hazardous asteroids larger than 140 m [106]. The NEO Surveyor spacecraft will be working in the orbit of Sun-Earth L\({}_{1}\)[107, 106], the first Lagrange point of Sun-Earth, so that it can take a closer look at the Sun and objects inside Earth's orbit [108, 106]. As a successor to the NEOWISE mission, the NEO Surveyor mission was implemented by PDCO. In January 2021, NASA authorized the mission to proceed to the preliminary design phase with the JPL leading the development [106]. In terms of [109], the NEO Surveyor has used a 50-cm onboard telescope which is a bit larger than the 40-cm WISE telescope that has already successfully discovered 34,000 asteroids, including 135 NEOs. Its field of view is many times larger than WISE, enabling it to discover new NEOs with sizes as small as 30-50 m in diameter [109]. The detection improvement is largely accredited to new detector arrays (2048 \(\times\) 2048 pixels and produce 82 Gb of data per day [110]) which have been modified to detect longer infrared wavelengths while being optimized for looking into cold space with excellent noise characteristics. Furthermore, the good infrared performance does not necessitate the use of cryogenic fluid refrigeration. The detector can be passively cooled to 30 K. Thus, there will not be a performance degradation due to running out of coolant [110].  
Finally, the seal of the PDCO, OSIRIS-REx (in launch configuration), an the artist's depiction of the WISE (NEOWISE) and NEO Surveyor are illustrated in Figure 11, respectively.