7:44, January 26, 2022,

Changzheng No. 4 C Remote Control No. 29 rocket was launched at Jiuquan Satellite Launch Center, successfully sending land exploration No. 1 satellite A of group 01 to the predetermined orbit and fulfilling the mission of this launch.

The satellite and rocket in this mission are both developed by Shanghai Academy of Spaceflight Technology (SAST)

The land exploration No. 1 satellite, approved by the National Space Administration for project approval, is the first satellite model launched during the "Thirteenth Five-Year" for the Medium- and Long-Term Development Plan for Civil Space Infrastructure. It is composed of two identical L-band synthetic aperture radar (SAR) satellites, A and B. Repeated orbit differential interference deformation measurement and interference topography mapping will be realized in the fly-aside and fly-around modes after the satellites go into the orbits, respectively. As the first satellite of the land exploration No. 1 satellite group 01, the land exploration No. 1 satellite A of group 01 will work with the subsequently launched B satellite in the fly-aside mode for a long time to jointly construct the world's first L-band binary constellation used for surface deformation interferometry. In addition to the long-term fly-aside formation, the two satellites will also use the close fly-around formation to conduct collaborative observation, so as to realize the large-scale terrain measurement and improve the acquisition ability of understory terrain, which is an important support for the construction of natural resource survey system, the construction and update of global geographical information resources, and the update of high-precision terrain data. 

The land exploration No. 1 satellite A of group 01 weighs about 3.2 tons, and the total area of SAR antenna is more than 33 square meters. It is currently the largest SAR satellite of China in orbit. The satellite operates in a quasi-solar synchronous orbit at a height of 607 km and is equipped with an advanced L-band multi polarized multi-channel SAR load, which has all-day, all-weather, and multi-mode ground-to-ground observation ability. 

In order to ensure the measurement accuracy of repeated orbit differential interference SAR, according to Ruixiang Li, Chief Command of land exploration No. 1 satellite Group 01, this satellite uses on-board autonomous navigation and control system for strict regression orbital control, and the orbital pipeline control radius is less than 350 meters during repeated observation, reaching the international advanced level. After normal operation, the monitoring of surface deformation with wide range and millimeter accuracy under complex conditions will be realized, the ability of interference SAR measurement in vegetation coverage area improved, the early identification and monitoring ability of natural disasters, especially geological disasters, in China effectively supported, and it will also play an important role in the post-hoc investigation of earthquakes, large landslides, etc. 

The launch of the land exploration No. 1 satellite A of group 01 will realize the independent controllability of differential interference SAR data in China, significantly reducing the dependence of geological, seismic, emergency and other industrial applications on foreign SAR data, and providing strong spatial observation technical support for the realization of global objectives such as sustainable development.  

Changzheng No. 4 C carrier rocket is a normal temperature liquid three-stage carrier rocket developed under the leadership of SAST, with excellent performance and wide range of applications. For different types of satellites, the Changzheng No. 4 rocket can flexibly adopt launch modes with the ability to launch multiple types of satellites with different orbital requirements. It can implement a single or multiple satellite launch, and its solar synchronous circular orbit carrier capacity can reach 3 tons (orbital height 700 km). 

As introduced by Biao Cang , the Chief Command of Changzheng No. 4 series carrier rockets, the launch task is the opening battle of Changzheng No. 4 series rockets in 2022, and it is also the first task with CZ 4 "Redundant Improvement II" state in Jiuquan Satellite Launch Center; the rocket control system uses the "single-deck optical inertia group" state; the whole rocket uses lithium ion battery as power supply; the universal WRP002 carrier rocket ground measurement, launch and control system is used to realize the miniaturization, automation and unattended duty of the measurement, launch and control system. 

Since entering the field in 2022, the Changzheng No. 4 test team has been implementing the epidemic prevention policy of "two-point first-line" from dormitories to factories for seven days, and multiple rounds of nucleic acid detection have been completed; the model team and the launch site system have completed the comprehensive technical transfer and interface coordination, and conducted multi-level, multi-area and multi-angle in-depth exchanges in response to the changes in the rocket technical status, workflow and the use of new products and new equipment, which are the focus of attention by both parties, ensuring that the product quality is controlled, the workflow controlled, and thus the status comprehensively controlled.

This Changzheng No. 4 task has adopted the mature launching site quality confirmation system, integrating the on-site record form and quality confirmation process into the "digital management system", and realizing paperless work while tracking the work progress in real time. In addition, the test team adheres to the daily clearance system to ensure that each work item is continuously advanced and completed on time and that each work is to be handled in a timely and closed loop. 

It is winter, when Jiuquan is in the coldest weather of the year. According to the low temperature launch conditions, the model team has formulated the winter launch guarantee plan in advance and taken a variety of measures with the launch site system to ensure that the rocket test and launch conditions meet the requirements; the test team also has provided the team members with cold-proof materials such as cotton clothes, cotton caps, and heat preservation patches, providing a strong logistics support for the team members.

This launch is the 86th launch of Changzheng No. 4 series carrier rocket, the 152nd launch of Changzheng series carrier rocket developed under the leadership of SAST, and the 407th launch of Changzheng series carrier rocket.