Last changed: V0.2 - 17-04-2020
Sounding Rockets
Sounding rockets are rockets that fly into space but do not enter an orbit. They often serve as testbeds or as a cheaper alternative for orbital missions. As the experiments need to be returned to earth safely, they are often equiped with a parachute recovery system.
REXUS, MAXUS
Operator: SSC, DLR (Eurolaunch)
First flight: 1995 (REXUS), 1991 (MAXUS)
Status: Active (REXUS), Retired (MAXUS)
The parachute systems of both REXUS and MAXUS by themselves are not necessarily that interesting as they consist of a two-stage parachute system using a conical ribbon drogue parachute and a cross main parachute. However, the atmospheric entry of these rockets is quite interesting. During the atmospheric entry, one would like to decrease the ballistic coefficient, reducing the terminal velocity. This can be done by increasing the drag coefficient, which can be done by making the payload module aerodynamically unstable. The video on the right shows the entry of the REXUS 14 sounding rocket. First one can see the separation of the nose cone, at this point also the engine section is released. This causes the cylindrical module to become unstable. After a tumbling entry, one can see the drogue and later the main parachute deploys leading to a safe landing. As REXUS flies to an altitude of about 80 kilometres, there are no visual aerothermal effects. These effects can be seen on the MAXUS flights, as they fly to altitudes of about 700 km. The video below shows the flight of MAXUS-9.
The heat of entry can be seen as there is a yellow/red hue in the shot. After the atmospheric entry one can see that the camera lens was quite damaged and thus does not generate sharp images. An image of the parachute can be seen at the end of the video showing the size of the main parachute.
SARGE
Operator: EXOS Aerospace
First flight: August 2019
Status: Active
Named in honour of the driver from the British car show Top Gear [123] is/was an attempt by Armadillo aerospace to create a reusable launcher using parachutes. The first STIG-A launched in 2011 and was the first of three flights for this model. The launcher has a single LOX/Ethanol stage for sub-orbital flight with a target altitude of about 100km.
For the recovery of the launcher, uses a two-stage system and recovers the entire rocket. It deploys a ballute drogue parachute attached to both the nosecone and the propellant tank with the engine at apogee. This performs the initial deceleration from entry into the atmosphere as a ballute is deployed usually before entry. The tank and engine are detached from the ballute, and a parafoil is deployed following the ballute phase. This safely lands the engine and tank. The nosecone stays attached to the ballute and decelerates because of the loss of the engine and tank to a safe landing speed [120,122].
The STIG-A performed three flights, of which at least one seems successful, and the other two are unknown [115,117]. After this, the performance of the launcher was increased, which led to STIG-B. Again three flights were performed. However, all flights at least failed the recovery part of the flight due to failed deployments. After the last STIG-B launch, Armadillo was bought by EXOS Aerospace which continued with the STIG-B design and improved it into the SARGE launcher[6]. Four flights were performed with the SARGE launcher. All flights again had issues. However, this time the failures occurred during the powered phase of the flights. Often, during the initial seconds of the flight, the tank was successfully recovered at least once [119].
Miura 1
Operator: PLD Space
First flight: End 2022 (planned)
Status: In development
The Miura 1 rocket aims to fly end of 2020 and can bring 100 kg payloads to 150 km. The rocket is equipped with a parachute system for full rocket recovery. According to a paper presented at EUCASS2019, the drogue parachute opens at 5 km, and the main parachute opens at 3 km. The rocket performs what is described as a "passive aerobrake descent", it is unclear what is meant by this. The parachutes onboard Miura 1 are a 3m Conical Ringslot drogue and a 15.4m Hybrid Slotted Pyloconical main parachute. The main parachute is reefed to 10% upon opening. Several drop tests have been performed in the US. As the sounding rocket is meant to be fully reused, the drogue parachute is equipped with a kill line. This line contracts the drogue parachute killing the drag it generates.
In October 2023 PLD Space launched Miura 1 on a first mission. The apogee of the flight was lower than expected, according to statements this was due to range constrictions. After the flight, the rocket landed safely, but was not found after flight.
Super Loki
Operator: NASA
First flight: 1968
Status: Retired
The Super Loki rocket was a boosted dart-type sounding rocket with a single powered stage and an unpowered upper stage with better aerodynamic characteristics. The rockets were intended to perform meteorological studies mainly in the higher atmosphere. To increase measurement times a decelerator was included. This decelerator was called Starute. Previous rockets, such as ARCAS used a more conventional parachute for this task. However conventional parachutes had problems operating at the high altitudes required and would entangle during deployment. If deployment was successful the parachutes would often oscillate leading to a loss of signal. These issues were mitigated by the implementation of a Stable-Parachute abbreviated to Sta-rude or Starute.
The folded Starute would be about 1 inch in diameter and about 1 foot long or 2.5 by 30 cm. The decelerator would inflate using the residual air trapped inside the folded Starute. [124]
M-100
Operator: Russia
First flight: 1957
Status: Retired
The M-100 was a Russian sounding rocket that flew over 6000 times in its various configurations. One such configuration or mission was metrological research. To increase the measurement time a system was used to decelerate the 60 kg payload at a high altitudes, much like the Super Loki rockets. The Russians however opted for an ethyl acetate forced inflation system. in the vacuum of space the ethyl acetate boils off, generating a vapour which goes into inflation tubes in the parachute. This 42 m2 then inflates and float back to Earth. [125]
