5:15 PM - 6:30 PM
[MSD40-P12] Demonstration satellite mission for the next-generation precipitation observation radar technology
Keywords:Precipitation measurement, Doppler radar, Deployable antenna
In this research, as a basic technology for precipitation radar observation from a geostationary orbit in the future, a deployable antenna was developed, a prototype of the antenna deployment mechanism was produced, and the performance was confirmed in a ground test. Furthermore, we are proposing a small low-earth orbit satellite (HTV-X1) mainly for demonstrating the antenna deployment mechanism in orbit.
There are two technologies to demonstrate. The first is a technique for measuring the Doppler velocity of precipitation particles, which enables Doppler velocity measurement from space. The second is a technology for constructing a large planar antenna, which aims to make it possible to increase the size of the planar antenna and to construct a large planar antenna of 30 m x 30 m or more in orbit.
Technical novelty / advantage
① Precipitation Doppler velocity measurement technology
The Doppler velocity measurement technology for cloud particles is established by the Cloud Profiling Radar onboard the EarthCARE satellite and will be evaluated after the launch in 2023, but the Doppler velocity measurement technology for precipitation has not yet been established.
② About construction technology for large flat antennas
Although the technology for constructing a synthetic aperture radar for satellite mounting by one-dimensional deployment has been established, the technology for constructing a 30m-class large planar antenna by two-dimensional deployment has not yet been established. In addition, although the technology for constructing solar cell paddles by two-dimensional deployment has been established, planar antennas require more surface accuracy and rigidity than solar cell paddles, so the two-dimensional deployment technology for solar cell paddles is 30m class large. It cannot support the construction of a flat antenna. Among the mechanisms to be demonstrated, JAXA has applied for a patent for the "coupling mechanism using a solenoid", which is a new concept coupling mechanism.
Development progress
Regarding the feasibility of the proposed mission, assuming an on-orbit demonstration machine of 1.2m x 2.2m x 0.7m when stored and 1.2m x 2.2m x 4.4m when deployed, it will be mounted on the HTV-X exposed cargo mounting part. It is expected to meet the conditions. In addition, a thermal analysis of the demonstrator has been carried out, and it is expected that it will be established thermally. Furthermore, in FY2017, we demonstrated through ground experiments that the antenna deployment / coupling mechanism operates normally with half the size of the demonstration machine. If the size of the on-orbit demonstrator is set to 1.0 m x 1.0 m x 1.5 m or less when stored, the antenna size after construction and the detection sensitivity of the precipitation echo will decrease, but necessary verification is possible.
In FY2018, we devised a mechanism that allows the second row antenna panel to deploy independently even if the first row antenna panel did not deploy, and conducted a ground experiment using the same mechanism prototype model. As a result, it was confirmed that the self-sustaining deployment function of the second row antenna panel can be realized by adding a mass of about 1.3 kg.
In FY2019, we are carrying out a preliminary design of a deployable planar antenna assuming installation on the HTV-X No. 1, and as part of this, we will adjust the interface with the HTV-X side, analyze the panel deployment behavior, and partially prototype and test. Etc. are being implemented.
There are two technologies to demonstrate. The first is a technique for measuring the Doppler velocity of precipitation particles, which enables Doppler velocity measurement from space. The second is a technology for constructing a large planar antenna, which aims to make it possible to increase the size of the planar antenna and to construct a large planar antenna of 30 m x 30 m or more in orbit.
Technical novelty / advantage
① Precipitation Doppler velocity measurement technology
The Doppler velocity measurement technology for cloud particles is established by the Cloud Profiling Radar onboard the EarthCARE satellite and will be evaluated after the launch in 2023, but the Doppler velocity measurement technology for precipitation has not yet been established.
② About construction technology for large flat antennas
Although the technology for constructing a synthetic aperture radar for satellite mounting by one-dimensional deployment has been established, the technology for constructing a 30m-class large planar antenna by two-dimensional deployment has not yet been established. In addition, although the technology for constructing solar cell paddles by two-dimensional deployment has been established, planar antennas require more surface accuracy and rigidity than solar cell paddles, so the two-dimensional deployment technology for solar cell paddles is 30m class large. It cannot support the construction of a flat antenna. Among the mechanisms to be demonstrated, JAXA has applied for a patent for the "coupling mechanism using a solenoid", which is a new concept coupling mechanism.
Development progress
Regarding the feasibility of the proposed mission, assuming an on-orbit demonstration machine of 1.2m x 2.2m x 0.7m when stored and 1.2m x 2.2m x 4.4m when deployed, it will be mounted on the HTV-X exposed cargo mounting part. It is expected to meet the conditions. In addition, a thermal analysis of the demonstrator has been carried out, and it is expected that it will be established thermally. Furthermore, in FY2017, we demonstrated through ground experiments that the antenna deployment / coupling mechanism operates normally with half the size of the demonstration machine. If the size of the on-orbit demonstrator is set to 1.0 m x 1.0 m x 1.5 m or less when stored, the antenna size after construction and the detection sensitivity of the precipitation echo will decrease, but necessary verification is possible.
In FY2018, we devised a mechanism that allows the second row antenna panel to deploy independently even if the first row antenna panel did not deploy, and conducted a ground experiment using the same mechanism prototype model. As a result, it was confirmed that the self-sustaining deployment function of the second row antenna panel can be realized by adding a mass of about 1.3 kg.
In FY2019, we are carrying out a preliminary design of a deployable planar antenna assuming installation on the HTV-X No. 1, and as part of this, we will adjust the interface with the HTV-X side, analyze the panel deployment behavior, and partially prototype and test. Etc. are being implemented.