Solar Thruster Sailor (STS) - Fig. 9 - Thruster Ring Spacecraft as a Catcher Space Tug
- Đ Frank Ellinghaus -

I N D E X - G E R M A N

POST & AUTHOR & Vision
STS - Solar Thruster Sailor
RSS - Ring Skeleton Structure LTH - Launcher Transport Head EFO - Experimental Flying Object RSC - Rotational Slingshot Catapult
L I N K S ENGLISH

Fig.1 - Fig.2a-2b - Fig.2c - Fig.2d - Fig.3a-3b - Fig.4a-4c - Fig.5 - Fig.6 - Fig.7 - Inner Ring - Flying Ring - Fig.8 - Fig.8a - Fig.8b - Fig.9 - Fig.9a - Fig.10 - Fig.11

Fig. 9 - Thruster Ring Spacecraft as a Catcher Space Tug - N E W

Figure 9 shows a space craft which would serve as a space tug. Itīs light weight outer ring is driven by electric thrusters ( ion or hall for instance ). Inside a thruster ring is a net placed which serves as a device to "catch" space debris for cleaning orbital space from hubris or to enhance the orbit of satellites. It is also thought to catch materials throwed through a mass driver for instance from the moon to moon orbit.

Even catching or deflecting asteroids and comets for planetary asteroide defence seems possible when a huge space tug is used. For launch and construction of an oversized thruster ring take a look at RSS - Ring Skeleton Structure and LTH - Launcher Transport Head . Those tugs could get operated through a community of all spacefaring nations which are most interested to substain a clean earth orbit.

Thrusterring Spacecraft as a Space Tug
Since electric thrusters with low thrust allow for gentle movements catching scrap or sattellites is possible. The objects caught get hold in the catcher bag through acceleration, unloading is possible through deceleration. So the craft could accelerate in direction of the moon and dump the debris on it.

The catcher net 2.7 is attached to the Thruster Ring through belts which also carry the solarcell arrays. The Outer Ring pipes, the belts, tethers or thread are preferably made of strong and lightweight nanotube like materials.

The thrusters are located in plugable complete thruster-tank units, each holding two thrusters in a thruster pipe. Each of the two thrusters fires to the opposite to itīs partner in the pipe. In conjunction with two partner complete units design were always two units are mounted conversely at the ring this allows to stop, accelerate, deaccelerate, turn the craft in each direction wanted without needing moveable thruster mountings - just through firing different thrusters. So this spacecraft is highly steerable.

Because of the complete thruster unit concept with easily changeable thrusters through plugging/unplugging the craft could get fueled and updated with better thrusters in a wash and at the same time.

In the drawing above we can see four thruster units 1.5 for turning the craft araund the disks centrum or for accelerating / deaccelerating the disk plane forward / backward or sidewards. Since this is possible just with two double units we have double redundancy.

The main propulsion thrust should come from the thrusters 1.6, which can push the the catching net towards the objects or deaccelerate to dump the. There are 12 double thruster units thought to be used at least for units together. So we have at least 3 times redundancy here.

Wouldnīt the craft get to much mass with such a lot of thruster units? If using for instance Russian SPT 60 hall thrusters each weighting about 1.2 kg for those 16 double thruster units we get about 40 kg for the thruster units without fuel.

If we would use a 100-m diameter outer ring made of CNT, this would account for about 60,000 cubic cm = 78 kg earth weight. (diameter of the pipes 6 cm, 1 mm strength of the pipe walls, diameter of the ring 100 m = 100 m x 3,1428... x 6 cm x 3,1428 x 1 mm = about 60,000 cubic cm that is about 78 kg).

I admit I used the very optimistic numbers for carbon nano tube structures (not carbon reinforced plastics) which have been used through Edwards/Westling for the Space Elevator which may not be realistic for the near future.

Comparison to Smart I


I wanted to come to a comparable example to Smart I, the European Space probe which is on itīs way to the Moon and is now reaching Moon-orbit. Smart I has a weight of 367 kg and produces with itīs single SPT-100 Hall Thruster derivate 70 mN of thrust. When allowing besides ring and thrusters about 250 kg for the rest of the structure (solar cells, fuel, belts, net, bus, optics and other payload) we have with the Thrusterring Space Tug a similar weight, but a much more usable spacecraft with about 360 mN of thrust (30mN each), when using all 12 in one direction mounted thruster units for acceleration.

Using this design for asteroid deflection even for bigger asteroids would be also possible. First we would have a huge ring with a lot more of thrusters. Since we are not restricted to electric thrusters, we could add stronger chemical thrusters to the ring and use the electric propulsion mainly to transport the space tug to the asteroid. The stronger chemical thrusters would get fired, when the contact to the asteroide is made.

Since the thruster ring is also able to carry a solar sail we could place such deflection tugs far away around earth location waiting for asteroids to come. With an additional observation fleet of small solar sail satellites brought out with a carrier solar sail we could be able to prevent asteroids or comets to surprise us and taking countermeasures at the right time.

steering the craft
This craft is thought for remote operation. I do call the operator who steers the craft " robonaut " since it is most likely that astronauts could steer the craft using virtual reality techniques. But the technique wouldnīt be restricted to astronauts in space, it would also be possible (and cheaper) that earthbased robonauts stear such craft.

This is how I imagine steering the tug. If you take a look on top of the thrusters 1.5 are cameras 1.2.2. They shall provide a stereo look as the craft would be the turning head. When the robonaut moves his head (or his whole body when he is using a wearable monitor) to the right, the craft would turn right, when he moves the head or his body to the left, the craft would turn left. He could also move his head up and down and the craft would move accordingly. He could than steer how much the thrusters are firing for acceleration or deceleration with his hands. Also with his hands he could switch an automatic stop function were the crafts thrusters are directed to stop an acceleration or a turn he just initiated to a standstill.

Thrusters

Fig. 2.a and Fig. 2.b - Thruster Units up - down and right - left

Fig. 2.a, Fig. 2.b

Thruster units, parts 1.9 are at the same time brackets and tank units for xenon-gas. Parts 1.10 are jet tubes consisting of two thrusters with outlet to opposed directions.


Fig. 2.c - Thruster Unit - Installation

Fig. 2.c - Thruster Unit - Installation

The two splints of the bracket 1.9 run completely through the segment-pipes and are boltet onto them with counter nuts. The splints are also conductors for the electric power yielded from the solar-cells near the thruster-unit. Half-pipes (could be from metal) 1.9.2 enfold the segment pipes to give this joints some more strength since they have to resist heavy rotational forces.


Fig. 2.d - Double Thruster Unit with two typical ion thrusters.

Fig. 2.d, double thruster unit with typical ion thrusters

The bracket for the unit is at the same time tank for xenon gas.


to the next Fig. 9a - The Flying Space Bag

Fig.1 - Fig.2a-2b - Fig.2c - Fig.2d - Fig.3a-3b - Fig.4a-4c - Fig.5 - Fig.6 - Fig.7 - Inner Ring - Flying Ring - Fig.8 - Fig.8a - Fig.8b - Fig.9 - Fig.9a - Fig.10 - Fig.11

I N D E X - G E R M A N

POST & AUTHOR & Vision
STS - Solar Thruster Sailor
RSS - Ring Skeleton Structure LTH - Launcher Transport Head EFO - Experimental Flying Object RSC - Rotational Slingshot Catapult
L I N K S ENGLISH