India’s space agency successfully tests prototype for controlling descent of spent 1st stages
India’s space agency ISRO on September 3, 2022 successfully used a suborbital sounding rocket to test a prototype of an inflatable airbag, which it dubs an Inflatable Aerodynamic Decelerator (IAD), that can inflate at the top of a 1st stage and slow and control its descent back to Earth after launch.
The graphic to the right was adapted from the mission brochure [pdf]. According to ISRO:
The IAD was initially folded and kept inside the payload bay of the rocket. At around 84 km altitude, the IAD was inflated and it descended through atmosphere with the payload part of sounding rocket. The pneumatic system for inflation was developed by LPSC. The IAD has systematically reduced the velocity of the payload through aerodynamic drag and followed the predicted trajectory. This is first time that an IAD is designed specifically for spent stage recovery. All the objectives of the mission were successfully demonstrated
ISRO claims this design can not only facilitate the reuse of first stages, it can also be used for science payloads to Mars and Venus.
I look at this and wonder, wouldn’t parachutes or parasails, already developed and used numerous times in similar applications, do the same job? In fact, Rocket Lab has already successfully used parachutes to control the re-entry of its Electron first stages. Meanwhile, SpaceX uses simple and lightweight grid fins to control the descent of its Falcon 9 first stages, and simply fires that stage’s engines twice to slow it down for landing.
While there may be engineer advantages to this airbag design, the whole thing smacks of many of NASA’S complex test programs that never made it past prototype tests. The ideas always looked good, but they never were practical or cost effective.
India’s space agency ISRO on September 3, 2022 successfully used a suborbital sounding rocket to test a prototype of an inflatable airbag, which it dubs an Inflatable Aerodynamic Decelerator (IAD), that can inflate at the top of a 1st stage and slow and control its descent back to Earth after launch.
The graphic to the right was adapted from the mission brochure [pdf]. According to ISRO:
The IAD was initially folded and kept inside the payload bay of the rocket. At around 84 km altitude, the IAD was inflated and it descended through atmosphere with the payload part of sounding rocket. The pneumatic system for inflation was developed by LPSC. The IAD has systematically reduced the velocity of the payload through aerodynamic drag and followed the predicted trajectory. This is first time that an IAD is designed specifically for spent stage recovery. All the objectives of the mission were successfully demonstrated
ISRO claims this design can not only facilitate the reuse of first stages, it can also be used for science payloads to Mars and Venus.
I look at this and wonder, wouldn’t parachutes or parasails, already developed and used numerous times in similar applications, do the same job? In fact, Rocket Lab has already successfully used parachutes to control the re-entry of its Electron first stages. Meanwhile, SpaceX uses simple and lightweight grid fins to control the descent of its Falcon 9 first stages, and simply fires that stage’s engines twice to slow it down for landing.
While there may be engineer advantages to this airbag design, the whole thing smacks of many of NASA’S complex test programs that never made it past prototype tests. The ideas always looked good, but they never were practical or cost effective.