China develops net launcher to combat space debris

Net thrower under test. The experimental device is on the left, marked with an oval

The problem of space debris is proposed to be solved in different ways. First of all, various specialized spacecraft-cleaners with special equipment are being developed. Recently, Chinese specialists proposed their own version of "weapons" for satellites. They developed and tested an original version of a device for collecting small fragments, suitable for use on different platforms.

Designed and tested

The new system was developed by specialists from Nanjing, Shenyang and Shanghai universities. The project was headed by Associate Professor Yue Shuai from Nanjing. The specialists published a report on their work in the Chinese scientific journal Acta Aeronautica et Astronautica Sinica. This publication recently attracted the attention of Chinese and foreign media.

The goal of the new project was to create a device for capturing, transporting and deorbiting space debris. In the future, it is proposed to mount such a device on specialized collector satellites and use it to clear space.

The new device is a small launcher that shoots a special net. The soft "ammunition" made of threads should cover and entangle the target, and then provide for its towing and/or deorbiting. Despite the simplicity of the idea, the design of the launcher-net launcher and the projectile had to include several original solutions.

First of all, the problem of recoil was solved. The launch of the grid, despite its small mass, creates an impulse pushing the launcher and its carrier. Recoil can knock the spacecraft off course and interfere with its normal functioning and the solution of work tasks.

Chinese specialists have introduced several elements into the design of the launcher designed to dampen recoil. In addition, various emissions, flashes, etc. have been virtually eliminated. All these measures should improve operational and other characteristics.

Representatives of three universities developed a project and built a pilot launcher. It passed laboratory tests and confirmed the correctness of the main technical solutions. In addition, it was possible to find the optimal configuration of key parts.

The results of the project and experiments were published in a peer-reviewed journal. The future of this development remains unknown. It is quite possible that it will be developed further and will find application in real space technology in the future.

Design features

The authors of the project published photographs taken during laboratory tests. Despite the poor quality, one can understand the main features of its design. In addition, original solutions are revealed, due to which the required characteristics are provided.

The photo shows a cylindrical device that includes several main components. These are oblong parts of a circular cross-section of different sizes with various functions. During the tests, it was suspended inside a cylindrical frame to evaluate and measure the recoil.

The launcher is a single-shot barrel. Only one shot is possible, after which manual reloading is required. This feature is not critical for a prototype, which should only demonstrate the operability of the design.

A powder charge is used to launch the net. The throwing device-barrel is built according to the scheme of a cartridge with a cut-off of powder gases. Inside it there is a movable piston that transmits gas pressure to the projectile, but blocks the gases inside and does not allow them to escape. This solution reduces the recoil and also eliminates emissions into the surrounding space.

The net is placed in a small container. The container is accelerated by a moving piston, exits the barrel and opens, releasing the net. An original solution is proposed to compensate for the recoil created by the container.

Near the muzzle of the barrel there is a ring-membrane in the form of a truncated cone made of elastic material. When leaving the installation, the container with the grid interacts with the ring and causes it to deform. Part of the container's energy is transferred to the membrane and the body of the trigger. Due to the membrane, the trigger receives a forward impulse. It completely compensates for the recoil generated by the movement of the container with the grid. Experiments have shown that a conical membrane with an angle between the surface and the barrel bore of 35° is optimal.

The container with the net exits the barrel

The prototype, equipped with an optimally designed membrane, showed almost no recoil during testing. When fired, it moved only 3,45 mm. Unfortunately, the dimensions and weight of the net thrower and "ammunition" are not reported. The ballistic parameters are also unknown. Therefore, it is impossible to understand how effective the new device turned out to be.

Applications

A new development by three Chinese universities could find application in the rocket and space industry and help combat space debris. Based on this project, full-size launchers could be created for installation on spacecraft.

Using such devices, specialized cleaning satellites can be created. On board such a device there should be means for searching for a target and guiding it, as well as engines for maneuvering, including with active orbit change. The satellite should carry a set of single-use launchers - one per target.

Such a satellite would be able to enter the required orbit and approach the designated object. It would have to aim at such a target and fire a grid. Apparently, fragments and debris would be towed and then deorbited along with the cleaning satellite. Perhaps in the future, other methods of garbage disposal without losing the spacecraft will be found.

The main feature of the new net launcher is the almost complete absence of recoil. The impulse from the shot will not knock the carrier satellite off the specified orbit, and possible disturbances will be easily compensated by the standard maneuvering engines.

The foreign press has taken notice of the new Chinese development, and some publications have responded to it in a characteristic way. They have begun to view the device for combating space debris as a new type of weaponsThere are concerns that China will gain additional capabilities to damage or destroy other countries' satellites.

In theory, the net could be used against operational satellites in orbit. However, the feasibility of such use is questionable. The net is unlikely to cause significant damage to the target spacecraft, and towing it out of orbit is associated with known difficulties.

At the same time, the new device can probably shoot not only a container with a net. The net's place can be taken by a striking element such as a bullet or projectile. In this case, the carrier device gets the ability to shoot at its targets and cause them significant damage without risk to itself.

In laboratory conditions

Thus, Chinese specialists have once again offered an interesting solution to a pressing problem. They managed to create an original launch device, as well as improve its main characteristics, taking into account the specifics of use in space.

A prototype of a shooting device with a net has already passed laboratory tests and demonstrated the required parameters. However, the future of this project is still in question. It is not yet known whether the existing net launcher will be developed and adapted for use in space exploration.

Comments

[Civil]

This way they will get to the mass starlinks.

[Shurik70]

It won't go unnoticed.
We need to get close to the enemy satellite. And they'll notice.
It is more effective to use kinetic weapons. Let's say, a satellite changes its orbit by ejecting gas under pressure. A normal, non-suspicious event. And a satellite with gas shoots a burst of several hundred small ceramic balls, which no radar can see, with the calculation that the balls intersect with the enemy satellite. In opposite orbits, the speed of the balls will be 14-15 km/s, enough to destroy the satellite and evaporate themselves.

[Maks1995]

Some media here (and not in the West, as in the article) are already loudly rejoicing - the Chinese will launch weapons against satellites into space....
Here too - the very first comment - "and they will get to the mass starlinks."

As the saying goes, it's easier to destroy than to build

[Dedok]

As the saying goes, it's easier to destroy than to build

What, don't we have "dual-use" products?

[cpls22]

It is strange to care about millimeters of displacement of the device during firing (given that the mass of the device is only a part of the spacecraft), and not to say anything about the method of towing already captured debris. The disposability of such a net thrower seems to hint that equipping a spacecraft with it is unprofitable. This device looks more like a development against UAVs of the copter type for air platforms, or something important is missing in the description of the device, maybe the small size of such a module, allowing equipping a spacecraft in large quantities.

[Andy_nsk]

The disposable nature of such a net thrower seems to hint that equipping a spacecraft with it is unprofitable.

I wouldn't even consider a disposable option. The satellite itself is apparently supposed to be reusable. The procedure should look like this: the cleaning satellite captures trash in a net, slows down with the trash just below the first cosmic velocity (1KS), detaches the trash, accelerates to 1KS, and heads for the next piece of debris. Naturally, some fuel will be needed for maneuvering. Possibly renewable.

[cpls22]

Then it all comes down to the number of these net-thrower launchers - they are, after all, powder-based, disposable. Let's say he shot them all - what else is he supposed to do in orbit?

[Andy_nsk]

The shuttle arrived and brought fuel and nets.

[cpls22]

Quote from Andy_nsk

The shuttle arrived and brought fuel and nets.

Chinese?

[Andy_nsk]

The Chinese are also working on reusable ships. Although this is the area of work in which international cooperation could be organized... but this is politics, and I am more into the technical part...

[cpls22]

So far everything is going in the opposite direction - everyone is striving for self-sufficiency. Maybe they are designing shuttles, but such development of methods for capturing space objects and bringing them down from orbit is more like a program to combat spacecraft than garbage. In this version, the number of captures is not so critical - even a small number justifies the means.

[Andy_nsk]

Unlikely. It's too difficult to pull an enemy spacecraft out of orbit. It's easier - just shoot it with a Gauss cannon or a mini-rocket while flying past. That way you'll destroy more spacecraft.

[cpls22]

Quote from Andy_nsk

It's easier - fly past and shoot with a Gauss cannon or a mini-rocket. This way you'll destroy more devices.

These options do not solve the problem of consequences - a dead uncontrolled spacecraft in orbit and/or its debris, threatening the "cleaner" as well. Dirty work. But if such a "terminator" attracts a dozen or more other spacecraft (as many as the net-throwing modules will suffice), and then knocks it down from orbit - then the ends are in the water, the field for further action is free.

[Andy_nsk]

That is, in the end the result still comes down to removing the debris.

[cpls22]

Quote from Andy_nsk

That is, in the end the result still comes down to removing the debris.

I do not agree. There is a difference.

[SmolH2]

Regarding profitability.

There are an estimated 170 million fragments of 1 mm or larger in size, 670 fragments larger than 1 cm, and 29 fragments larger than 10 cm in size in Earth orbit.

So, it's more like testing out technologies. But definitely, if it's practice, then it's for something more real... The abduction of a satellite is already more real.

[Saxahorse]

What nonsense... A bunch of words about the space net thrower's fight against recoil, but not a word about what the net is made of and how they hope to stop space debris flying at a speed much higher than a bullet with this thing.

[SmolH2]

So it will also fly at the same speed... And getting it out of orbit is a matter of technology and fuel.

[Jacques sekavar]

The net is designed for large fragments, but it won't handle small ones, and a collision with even a small nut on a head-on collision can cause irreparable damage to the net launcher.
Perhaps, for space debris removal, there are several devices in a series of different missions – a caravan in which the lead device catches large fragments, and the subsequent ones – medium, small, and very small ones.
It's difficult to absorb the full force of a collision, but it's possible, like the graders that clear roads of snow, to direct the force of the impact in any direction, for example, into the Earth's atmosphere, where they will burn up safely, just like spacecraft that have reached the end of their service life.