Maneuvering spacecraft having solar sails
Embodiments herein describe maneuvering a spacecraft using a solar sail when sunlight is not available. Smaller satellites may rely solely on solar sails in order to maneuver to different locations (e.g., different orbits) to adjust for orbital decay, avoid collisions with other satellites, or to avoid space junk. However, solar sails cannot rely on the sun when orbiting on the dark side of a planet (e.g., when in the earth's shadow). When a spacecraft should maneuver but the sun is not available as a power source, the embodiments herein describe identifying other spacecraft within line-of-sight (LOS) of the spacecraft and using these spacecraft to direct lasers (or reflecting sunlight if available) at the spacecraft to maneuver it to a desired path (e.g., a new orbit).
1. A method comprising:
identifying a first spacecraft that needs to be maneuvered, wherein the first spacecraft comprises a solar sail;
upon determining the first spacecraft is in a shadow cast by an object in space, identifying a plurality of spacecraft within line of sight (LOS) of the first spacecraft;
determining a subset of the plurality of spacecraft that can cause a desired acceleration of the first spacecraft by emitting light at the first spacecraft; and
directing light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft.
2. The method of claim 1 , wherein the plurality of spacecraft each comprise a laser which can be controlled to emit light at the first spacecraft.
3. The method of claim 1 , wherein directing light from the subset of the plurality of spacecraft to the solar sail comprises at least one of: emitting light from one or more lasers on the subset of the plurality of spacecraft or reflecting sunlight at the subset of the plurality of spacecraft in a direction towards the solar sail.
4. The method of claim 1 , wherein the subset of the plurality of spacecraft comprises two or more spacecraft, wherein the two or more spacecraft direct light at the first spacecraft simultaneously.
5. The method of claim 1 , wherein the first spacecraft and the plurality of spacecraft are satellites orbiting the object casting the shadow.
6. The method of claim 1 , further comprising, after directing light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft:
determining whether the first spacecraft is on a desired path; and
upon determining the first spacecraft is not yet on the desired path and the first spacecraft is still in the shadow:
identifying a second plurality of spacecraft within LOS of the first spacecraft,
determining a second subset of the plurality of spacecraft that can cause the desired acceleration of the first spacecraft by emitting light at the first spacecraft, and
directing light from the second subset of the plurality of spacecraft to the solar sail of the first spacecraft.
7. The method of claim 1 , further comprising, after directing light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft:
upon determining the first spacecraft is not yet on a desired path and the first spacecraft is no longer in the shadow:
relying on sunlight to move the first spacecraft to the desired path, and
instructing the subset of the plurality of spacecraft to no longer direct light at the first spacecraft.
8. A computer program product for maneuvering a first spacecraft comprising a solar sail, the computer program product comprising:
a computer-readable storage medium having machine readable code embodied therewith, the machine readable code executable by one or more computer processors to perform an operation, the operation comprising:
upon determining the first spacecraft is in a shadow cast by an object in space, identifying a plurality of spacecraft within LOS of the first spacecraft;
determining a subset of the plurality of spacecraft that can cause a desired acceleration of the first spacecraft by emitting light at the first spacecraft; and
directing light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft.
9. The computer program product of claim 8 , wherein the plurality of spacecraft each comprise a laser which can be controlled to emit light at the first spacecraft.
10. The computer program product of claim 8 , wherein directing light from the subset of the plurality of spacecraft to the solar sail comprises at least one of: emitting light from one or more lasers on the subset of the plurality of spacecraft or reflecting sunlight at the subset of the plurality of spacecraft in a direction towards the solar sail.
11. The computer program product of claim 8 , wherein the subset of the plurality of spacecraft comprises two or more spacecraft, wherein the two or more spacecraft direct light at the first spacecraft simultaneously.
12. The computer program product of claim 8 , wherein the first spacecraft and the plurality of spacecraft are satellites orbiting the object casting the shadow.
13. The computer program product of claim 8 , wherein the operation further comprises, after directing light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft:
determining whether the first spacecraft is on a desired path; and
upon determining the first spacecraft is not yet on the desired path and the first spacecraft is still in the shadow:
identifying a second plurality of spacecraft within LOS of the first spacecraft,
determining a second subset of the plurality of spacecraft that can cause the desired acceleration of the first spacecraft by emitting light at the first spacecraft, and
directing light from the second subset of the plurality of spacecraft to the solar sail of the first spacecraft.
14. The computer program product of claim 8 , wherein the operation further comprises, after directing light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft:
upon determining the first spacecraft is not yet on a desired path and the first spacecraft is no longer in the shadow:
relying on sunlight to move the first spacecraft to the desired path, and
instructing the subset of the plurality of spacecraft to no longer direct light at the first spacecraft.
15. A system, comprising:
a first spacecraft comprising a solar sail;
a plurality of spacecraft that are within LOS of the first spacecraft; and
a spacecraft maneuvering system configured to:
identify that the first spacecraft needs to be maneuvered;
upon determining the first spacecraft is in a shadow cast by an object in space, determine a subset of the plurality of spacecraft that can cause a desired acceleration of the first spacecraft by emitting light at the first spacecraft; and
direct light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft.
16. The system of claim 15 , wherein the plurality of spacecraft each comprise a laser which can be controlled to emit light at the first spacecraft.
17. The system of claim 15 , wherein directing light from the subset of the plurality of spacecraft to the solar sail comprises at least one of: emitting light from one or more lasers on the subset of the plurality of spacecraft or reflecting sunlight at the subset of the plurality of spacecraft in a direction towards the solar sail.
18. The system of claim 15 , wherein the subset of the plurality of spacecraft comprises two or more spacecraft, wherein the two or more spacecraft direct light at the first spacecraft simultaneously.
19. The system of claim 15 , wherein the first spacecraft and the plurality of spacecraft are satellites orbiting the object casting the shadow.
20. The system of claim 15 , wherein the spacecraft maneuvering system is configured to, after directing light from the subset of the plurality of spacecraft to the solar sail of the first spacecraft:
determine whether the first spacecraft is on a desired path; and
upon determining the first spacecraft is not yet on the desired path and the first spacecraft is still in the shadow:
identify a second plurality of spacecraft within LOS of the first spacecraft,
determine a second subset of the plurality of spacecraft that can cause the desired acceleration of the first spacecraft by emitting light at the first spacecraft, and
direct light from the second subset of the plurality of spacecraft to the solar sail of the first spacecraft.