# How Satellites Use Thrusters to Balance Solar Panels

> A design for a satellite that uses strategically placed thrusters to counteract the physical twisting force caused by sunlight hitting its solar panels.

- **Patent:** US 10618678
- **Original title:** Self-balancing solar array
- **Owner:** Space Systems Loral LLC
- **Granted:** 2020
- **Status:** Active
- **Times cited:** 1
- **Field:** aerospace, mechanical, telecommunications

## What it does

This patent describes a spacecraft configuration designed to solve the problem of solar radiation pressure. When sunlight hits a large solar array, it creates a torque, or twisting force, that can push the satellite off its intended path. The invention places a thruster on the far end of the solar array to fire in the opposite direction, effectively cancelling out that twist. It also specifies that the satellite's main thrusters are placed on the opposite side of the main body to maintain balance. To keep things simple, the design uses a wireless radio link to control the thruster on the solar array, avoiding the need to run complex power or data cables through the rotating joint that connects the array to the satellite body.

## What it does NOT cover

- Does not cover satellites that use traditional mechanical reaction wheels to manage attitude control.
- Does not cover solar arrays that are fixed in place and do not rotate relative to the main body.
- Does not cover systems where power for the secondary thruster is supplied directly through the solar array drive assembly.
- Does not cover spacecraft that utilize only chemical propulsion without the specific thruster-to-torque-cancellation geometry described.

## The clever bit

The innovation lies in using a wireless radio link to control a thruster located on a moving solar array, which eliminates the need for complex, failure-prone electrical slip rings or cable wraps at the rotating joint.

## Real-world examples

1. Geostationary communications satellites
2. High-power orbital platforms with large solar arrays

## Why it matters

Managing a satellite's orientation in orbit is critical for keeping its antennas pointed at Earth and its solar panels aimed at the sun. By using thrusters to actively counteract solar pressure, this design potentially reduces the need for heavy, mechanical gyroscopes or reaction wheels. This allows for lighter satellites and more efficient station-keeping in geostationary orbit.

## Frequently asked questions

### What does How Satellites Use Thrusters to Balance Solar Panels cover?

A design for a satellite that uses strategically placed thrusters to counteract the physical twisting force caused by sunlight hitting its solar panels.

### Who owns patent US 10618678?

Space Systems Loral LLC owns this patent, granted in 2020.

### When does this patent expire?

This patent is expected to expire on April 14, 2040, when the invention enters the public domain.

### What is patent US 10618678 cited by?

This patent has been cited by 1 later patents that build on its ideas.

### What problem does this patent solve?

Managing a satellite's orientation in orbit is critical for keeping its antennas pointed at Earth and its solar panels aimed at the sun. By using thrusters to actively counteract solar pressure, this design potentially reduces the need for heavy, mechanical gyroscopes or reaction wheels. This allows for lighter satellites and more efficient station-keeping in geostationary orbit.

### What does this patent NOT cover?

Does not cover satellites that use traditional mechanical reaction wheels to manage attitude control.

**Full plain-English explainer:** https://patentbrief.org/patent/us/10618678/raptor-full-flow-staged-combustion-engine

**Original patent:** https://patents.google.com/patent/US10618678

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._