Capturing device and spacecraft
A driving mechanism controller included in a capturing device causes one or more driving mechanisms to spread a tethering member having an elongated shape to the outside of a housing by a target spread length. The driving mechanism controller, when an artificial space object is located in the area surrounded by the tethering member, causes the one or more driving mechanisms to retract the tethering member to the inside of the housing until at least a part of the tethering member comes into contact with the artificial space object. The tethering member is stable in a first shape having a curved section orthogonal to a linear extending direction of the tethering member.
1. A capturing device to be installed in a spacecraft to capture an artificial space object, the capturing device comprising:
a tethering member having an elongated shape, the tethering member being stable in a first shape having a curved section orthogonal to a linear extending direction of the tethering member;
two retaining members to each retain a corresponding end of ends of the tethering member;
a housing including an opening, the housing being configured to accommodate at least a part of the tethering member and the two retaining members;
one or more driving mechanisms to spread the tethering member to an outside of the housing through the opening, or retract the tethering member to an inside of the housing;
a deformer to deform a part of the tethering member in a direction of expanding an area surrounded by the tethering member, while the tethering member is being spread by the one or more driving mechanisms; and
driving mechanism controlling circuitry to cause the one or more driving mechanisms
to spread the tethering member to the outside of the housing by a target spread length defined by at least a shape and a size of the artificial space object, and
to retract, when the artificial space object is located in the area surrounded by the tethering member, the tethering member to the inside of the housing until at least a part of the tethering member comes into contact with the artificial space object.
2. The capturing device according to claim 1 , wherein
the deformer buckles a part of the tethering member, and
the tethering member spread to the outside of the housing has a partially buckled shape.
3. The capturing device according to claim 1 , wherein
the tethering member is partially wound around each of the two retaining members, and
the capturing device comprises two of the driving mechanisms provided inside the housing.
4. The capturing device according to claim 3 , wherein
the tethering member is accommodated inside the housing while being partially wound around each of the two retaining members, and
the tethering member is spread by the two driving mechanisms to the outside of the housing such that a U-shaped bent of the tethering member comes out first to the outside.
5. The capturing device according to claim 3 , wherein
the deformer is in either one of a separate state or a contact state, the separate state indicating the deformer separate from segments of the tethering member spread by the two driving mechanisms, the contact state indicating the deformer in contact with the segments of the tethering member spread by the two driving mechanisms, the deformer in the contact state being configured to make a distance between the segments of the tethering member larger than a distance between the two driving mechanisms, and
the capturing device further includes deformation controlling circuitry to cause the deformer to switch from the separate state to the contact state, when a length of the tethering member that has been spread to the outside of the housing reaches a first spread length, the first spread length being shorter than the target spread length and being defined by the shape and the size of the artificial space object.
6. The capturing device according to claim 5 , wherein the deformer includes a rotary mechanism capable of rotating between a position corresponding to the separate state and a position corresponding to the contact state.
7. The capturing device according to claim 5 , wherein the deformer includes an extending-contracting mechanism contractible to a position corresponding to the separate state and extendable to a position corresponding to the contact state.
8. The capturing device according to claim 3 , wherein the deformer includes a pair of first guides at positions more proximal to the opening than positions on both sides of the two driving mechanisms are, the first guides being arranged with a gap therebetween larger than a distance between the two driving mechanisms, the pair of first guides being configured to be in contact with segments of the tethering member spread by the two driving mechanisms on outer surfaces.
9. The capturing device according to claim 1 , wherein
the tethering member includes a first metal member and a second metal member, the second metal member being coupled to the first metal member and having a higher rigidity than a rigidity of the first metal member,
the first metal member is partially wound around one of the two retaining members, and the second metal member is partially wound around the other of the two retaining members,
the one or more driving mechanisms include two of the driving mechanisms provided inside the housing,
one of the two driving mechanisms spreads the first metal member to the outside of the housing through the opening, or retracts the first metal member to the inside of the housing, and
the other of the two driving mechanisms spreads the second metal member to the outside of the housing through the opening, or retracts the second metal member to the inside of the housing.
10. The capturing device according to claim 9 , wherein the deformer includes at least one second guide to guide a part of the first metal member in a direction away from the second metal member.
11. The capturing device according to claim 1 , wherein
the tethering member is partially wound around each of the two retaining members, and
the capturing device further includes a narrowing member disposed between the deformer and the one or more driving mechanisms, the narrowing member being configured to narrow a distance between segments of the tethering member unwound from the two retaining members by the one or more driving mechanisms, and then guide the tethering member to the deformer.
12. The capturing device according to claim 1 , wherein
the one or more driving mechanisms include two of the driving mechanisms provided inside the housing,
one of the two retaining members is attached to one of the two driving mechanisms, and
the one of the two driving mechanisms provided with the retaining member includes an extending-contracting mechanism extendable and contractible in a direction extending through the opening.
13. The capturing device according to claim 12 , wherein
the tethering member is partially wound around the other of the two retaining members, and
the deformer includes a third guide disposed at a position more proximal to the opening than the other of the two driving mechanisms is, the third guide being configured to guide, in a direction away from the one of the two driving mechanisms, the tethering member unwound from the other of the two retaining members.
14. The capturing device according to claim 1 , wherein the tethering member is stable in a second shape having a rectangular section orthogonal to an extending direction while being partially wound around any of the two retaining members.
15. The capturing device according to claim 1 , further comprising:
on-device information acquiring circuitry to acquire information on the shape and the size of the artificial space object, wherein
the one or more driving mechanisms spread the tethering member to the outside of the housing, by the target spread length of the tethering member defined by the shape and the size of the artificial space object acquired by the on-device information acquiring circuitry.
16. The capturing device according to claim 15 , wherein
the on-device information acquiring circuitry further acquires information on a positional relationship between the artificial space object and the tethering member, and
when the positional relationship acquired by the on-device information acquiring circuitry indicates that the artificial space object is located in the area surrounded by the tethering member, the one or more driving mechanisms retract the tethering member to the inside of the housing until at least a part of the tethering member comes into contact with the artificial space object.
17. A spacecraft for capturing an artificial space object, the spacecraft comprising:
a thruster of which a direction of ejection and a rate of ejection are controllable;
on-spacecraft information acquiring circuitry to acquire location information on the artificial space object and location information on the spacecraft;
thruster controlling circuitry
to determine, based on the location information on the artificial space object and the location information on the spacecraft acquired by the on-spacecraft information acquiring circuitry, a direction of ejection and a rate of ejection of the thruster for causing the spacecraft to approach the artificial space object, and
to control the thruster in accordance with the determined direction of ejection and the determined rate of ejection; and
the capturing device according to claim 1 .
18. The spacecraft according to claim 17 , wherein
after the one or more driving mechanisms included in the capturing device retract the tethering member to the inside of the housing until at least a part of the tethering member comes into contact with the artificial space object, the thruster controlling circuitry
determines, based on the location information on the artificial space object and the location information on the spacecraft acquired by the on-spacecraft information acquiring circuitry, a direction of ejection and a rate of ejection of the thruster for causing the artificial space object to depart from an original orbit of the artificial space object, and
controls the thruster in accordance with the determined direction of ejection and the determined rate of ejection.