2 ideas were embraced to enhance and improve the existing DGB parachute structure. One is to increase the drag coefficient. The disk part is hence customized to a structure with a higher drag coefficient, such as the hemisflo parachute structure and the triconical parachute structure. The other is to increase the size of the bands area to increase the parachutes stability, such as adding a tapered band on the lower skirt of the canopy. The particular parachute structures are displayed in the Figure. Credit: Space: Science & & Technology
How to handle the style, advancement, and credentials of the Tianwen-1 Mars parachute.
Chinas Tianwen-1 Mars probe effectively landed on the Utopia Plain at 7:18 a.m. Beijing Time, on May 15, 2021. In a research study paper recently released in Space: Science & & Technology, Mingxing Huang from Beijing Institute of Space Mechanics and Electricity carried out the design, advancement, and certification of the Tianwen-1 Mars parachute, which can supply a recommendation for the production of future Mars expedition parachutes.
The author first concentrated on the analysis and choice of Mars parachute types. Compared with the parachutes that work on Earth, the parachutes of the Mars lander face more problems. On one hand, the open flight of the Mars parachute is characterized by supersonic speed, low density, and low dynamic pressure. On the other hand, climatic activities, such as Martian vortex activity and dust storms, might cause severe parachute opening conditions. For that reason, difficulties in opening the parachute, unstable inflation, and reduced drag coefficient must be thought about in the design of parachute.
The disk part is thus customized to a structure with a greater drag coefficient, such as the hemisflo parachute structure and the triconical parachute structure. Afterward, to optimize the structure
for the Mars parachute, the subsonic, transonic, and supersonic wind tunnel tests were carried brought for the five DGB parachutes to obtain acquire drag coefficients and oscillation angles. Integrated with the wind tunnel test results at different Mach numbers to pick a parachute with much better deceleration and stability efficiency, the tapered DGB parachute were the finest deceleration parachute for the Tianwen-1. The deployment, inflation, and supersonic and subsonic aerodynamics of the parachute were examined by a suite of instruments, consisting of a high-speed video system trained on the parachute, a set of load pins at the user interface of the parachute bridles and the payload, and a GPS and inertial measurement unit (IMU )onboard the payload. The test results suggest that the drag coefficient of the tapered DGB parachute varied from 0.39 to 0.70 with the Mach number increased from Ma 0.2-Ma 2.4 and reached the maximum value of 0.7 at Ma 1.5; the maximum AOA after parachute implementation is about 20 °, which have all demonstrated that the performance of the tapered DGB parachute might meet the deceleration requirements of the Tianwen-1 Mars probe.
All of the other landers that have actually effectively accomplished soft landing on Mars have utilized the DGB (Disk-Gap-Band) parachute, which has good stability and exceptional inflation efficiency in the supersonic and low-density workplace. Due to its demonstrated high-altitude efficiency and lower technical danger, the DGB parachute with improved design modifications is selected as the prospect for the Tianwen-1 Mars probe. According to the ratio of the band area to the entire canopy, the DGB parachutes can be divided into the Viking type and the MPF (Mars Pathfinder) type. The Viking type DGB parachute has a high drag coefficient and weak stability, whereas the MPF and its improved DGB parachute have a smaller sized drag coefficient however much better stability. 2 concepts were embraced to optimize and improve the existing DGB parachute structure. One is to increase the drag coefficient. The disk part is therefore customized to a structure with a greater drag coefficient The other is to enlarge the bands location to increase the parachutes stability, such as including a tapered band on the skirt of the canopy. Thus, 5 DGB parachute structures, consisting of the MPF, Viking, hemisflo, tapered and triconical structure, were selected as prospects.
Descent, entry, and landing sequence of Tianwen-1 lander and Zhurong rover. Credit: Huang Xiangyu et al. DOI: https://doi.org/10.34133/2021/9846185 Later, to optimize the structure
for the Mars parachute, the subsonic, transonic, and supersonic wind tunnel tests were performed for the 5 DGB parachutes to acquire their drag coefficients and oscillation angles. Combined with the wind tunnel test results at different Mach numbers to select a parachute with better deceleration and stability performance, the tapered DGB parachute were the very best deceleration parachute for the Tianwen-1. To show the ability
of full scale tapered DGB parachutes in Mars flight conditions, four high-altitude flight tests were carried brought by sounding rockets in April 2018. During the flight, the very first stage burned out at elevations of around 17km ~ 20 km, respectively, the payload section reached apogee between 49km and 64 km. When the payload got the target vibrant pressure and Mach number, the parachute was mortar-deployed. The implementation, inflation, and supersonic and subsonic aerodynamics of the parachute were evaluated by a suite of instruments, including a high-speed video system trained on the parachute, a set of load pins at the user interface of the parachute bridles and the payload, and a GPS and inertial measurement unit (IMU )onboard the payload. After decelerating to subsonic speed, the parachute and payload descended to the test range for recovery. All of the tests targeted a specific dynamic pressure at parachute implementation to reach a wanted load on the parachute at complete inflation. The parachutes were mortar-fire released at vibrant pressures varying from 100Pa to 950Pa and Mach numbers between 2.05 and 2.35. In comparison, the parachute of Tianwen-1 need to have the ability to get opened dependably within the variety of Ma1.6 ~ Ma2.3 and dynamic pressure variety of 250Pa ~ 850Pa. Under the high-altitude opening test performed on the earth and the real working conditions of Mars, the Reynolds numbers are both in the order of 2 × 106. The test results indicate that the drag coefficient of the tapered DGB parachute differed from 0.39 to 0.70 with the Mach number increased from Ma 0.2-Ma 2.4 and reached the optimum worth of 0.7 at Ma 1.5; the maximum AOA after parachute deployment has to do with 20 °, which have all demonstrated that the performance of the tapered DGB parachute could satisfy the deceleration requirements of the Tianwen-1 Mars probe. Reference: “Analysis and Verification of Aerodynamic Characteristics of Tianwen-1 Mars Parachute “by Mingxing Huang, Wenqiang Wang and Jian Li, 20 March 2022, Space: Science & Technology.DOI: 10.34133/ 2022/9805457. Funding: Beijing Institute of Space Mechanics & Electricity.
