Graveyard orbit

Some old tools go to a far place.

This place is called a graveyard orbit. It stays far away from new tools. This keeps the new tools safe. It stops them from hitting each other.

Moving a tool to this far place is easier. It takes less fuel than falling down. Some tools go to a place far from Earth. They stay there for a long time.

Other tools must fall back to Earth. The air helps them fall down. They burn up in the air. This keeps space clean for everyone.

Space is very busy. Many satellites work high above Earth. When a satellite stops working, it must move. We call its new home a graveyard orbit. This is a place far from working tools.

Moving a satellite to this orbit is helpful. It helps stop space debris. Space debris is junk from old tools. Moving them prevents crashes. It is often easier to move up than down. To fall to Earth takes a lot of fuel. Moving to a graveyard orbit takes much less.

For some satellites, the move is a big task. It needs the same fuel used for three months of work. In the United States, the FCC makes rules for this. They say satellites must move when they finish their jobs. In 2023, one company was even fined for not doing this.

Other small satellites use a different way. They stay in a low orbit. The air around Earth helps them fall. This is called atmospheric drag. The air pulls them down until they burn up. This keeps space clean for everyone.

Space is a very busy place. Many satellites work high above our planet every day. When a satellite finishes its job, it must move away. We call this new path a graveyard orbit. It is also called a junk orbit or a disposal orbit. This orbit stays far away from the paths used by working spacecraft. Moving them helps stop them from hitting other things. This prevents the creation of space debris, which is junk in space.

Moving a satellite can be a hard job. Some satellites are very far from Earth in a geostationary orbit. To fall down to Earth requires a lot of fuel. This change in speed is called delta-v. For these satellites, moving up is much easier. A graveyard orbit is just a few hundred kilometers beyond the working orbit. This move uses about 11 m/s of delta-v. That is the same amount of fuel used for three months of stationkeeping.

Rules help keep space safe for everyone. In the United States, the FCC makes these rules. Any geostationary satellite launched after March 18, 2002, must plan to move. They must commit to moving to a graveyard orbit at the end of their life. U.S. government regulations even require a specific boost of about 274 m/s. In 2023, DISH received the first fine from the FCC. This was because they did not move their EchoStar VII satellite.

Scientists use math to find the best place for these orbits. The IADC gives a formula to find a safe height. This formula looks at the mass of the satellite. It also looks at the aspect area of the craft. It even considers solar radiation pressure. This is the pressure from light from the sun. The formula helps keep the protected zone clear. This allows other satellites to move without hitting the junk.

Different types of satellites use different ways to exit. Large networks in low Earth orbit use a different plan. They do not go to a high graveyard orbit. Instead, they move to a lower disposal orbit. In these orbits, atmospheric drag pulls them down. The air slowly slows them down until they fall. They will reenter the atmosphere and burn up within one year. Companies like SpaceX and OneWeb have promised to do this.

A graveyard orbit is a special path in space used to store old spacecraft. These orbits are also called junk orbits or disposal orbits. They sit far away from the paths used by active, working satellites. The main goal is to keep working spacecraft safe from collisions. When satellites crash, they create space debris, which is dangerous junk. Moving old satellites to these orbits reduces the chance of such accidents.

Moving a satellite can be a difficult process. Engineers must calculate the change in velocity needed for the move. This change in velocity is known as delta-v. For a satellite in geostationary orbit, falling down to Earth is very hard. It requires a delta-v of about 1,500 m/s to de-orbit. However, moving up to a graveyard orbit is much easier. This transfer only requires a delta-v of about 11 m/s. This move uses the same fuel as three months of stationkeeping.

There are different ways to handle satellites depending on their altitude. For satellites in geostationary or geosynchronous orbits, the graveyard orbit is just a few hundred kilometers higher. These satellites are often moved before they stop working entirely. This is because the positions at geosynchronous altitude have high economic value. However, the transfer requires reliable attitude control during the maneuver. Attitude control is how a spacecraft manages its orientation in space. Through 2005, only about one-third of satellite operators successfully completed these maneuvers.

Scientists use complex math to determine the safest height for these orbits. The Inter-Agency Space Debris Coordination Committee, or IADC, provides a specific formula. This formula calculates the minimum recommended perigee altitude. Perigee is the point in an orbit closest to Earth. The formula considers the mass of the satellite and its aspect area. It also includes the solar radiation pressure coefficient. This coefficient is a value between 1 for absorption and 2 for specular reflection. These factors help ensure the protected zone remains clear for active maneuvers.

Rules and regulations help manage these orbits to prevent chaos. In the United States, the Federal Communications Commission, or FCC, sets strict requirements. Any geostationary satellite launched after March 18, 2002, must commit to moving to a graveyard orbit. U.S. government regulations even require a specific boost of about 274 m/s. These rules ensure companies take responsibility for their equipment. In 2023, DISH became the first company to receive an FCC fine. This was because they failed to de-orbit their EchoStar VII satellite properly.

Satellites in near-geostationary orbits face unique environmental challenges. Uncontrolled objects in these areas show a 53-year cycle of orbital inclination. Inclination is the angle of the orbit relative to the Earth's equator. This cycle happens because of the interaction between Earth's tilt and the lunar orbit. The inclination varies by plus or minus 7.4 degrees. This change happens at a rate of up to 0.8 degrees per year. Once in a graveyard orbit, a spacecraft will typically be passivated. Passivation means removing energy sources to prevent accidental explosions.

New approaches are needed as space becomes more crowded. Large satellite networks in Low Earth Orbit, or LEO, use different methods. Unlike high graveyard orbits, these satellites use disposal orbits that decay naturally. Atmospheric drag, which is the friction from thin air, pulls these satellites down. This causes them to reenter the atmosphere and burn up within one year. Companies like SpaceX and OneWeb have committed to this method. This ensures that thousands of new satellites do not create long-term junk.