Amazonas 4A facts for kids

The Hispasat 74W-1 is a Spanish communications satellite. It was first called Amazonas 4A, then Amazonas 4, before getting its current name in 2017. This satellite was built by Orbital Sciences Corporation and is run by Hispasat. It launched in 2014 and was meant to work for 15 years. However, soon after launch, it had a power problem. This problem limited how well it could work and how long it would last.

The satellite is located to cover all of South America. It has helped broadcast big events like the 2016 Summer Olympics and World Cup football games.

About the Hispasat 74W-1 Satellite

The Hispasat 74W-1 satellite uses a design called the GEO Star-2.4 bus. It weighs 1,241 kg without fuel, which is called its dry mass. The satellite is shaped like a tall square box, about 5 meters high.

It has two large antennas that can unfold. It also has two solar panels that extend out. When these panels are fully open, the satellite is almost 23 meters wide. At launch, with all its fuel, the satellite weighed 2,938 kg.

How the Satellite Moves

The satellite has a main engine called the BT-4. This engine was made by a Japanese company, IHI Aerospace. It uses two types of fuel that mix together. The fuel is kept in special tanks that are filled with Helium gas to keep them pressurized.

The engine itself is 0.65 meters tall and weighs only 4 kg. It can produce 450 N of push, which helps the satellite move in space.

Keeping the Satellite Pointed Right

The satellite has a very advanced system to keep it pointed correctly. This system uses electric reaction wheels and small chemical thrusters. These thrusters use Hydrazine fuel. Together, they make sure the satellite always faces Earth precisely. This is important for sending and receiving signals.

Satellite Power System

The satellite needs electricity to work. It was designed to use up to 6.2 kW of power, but it actually uses about 4.8 kW. This power comes from two sets of solar panels. Each set has four panels made with special GaAs Solar cells.

The satellite also has two large Li-Ion batteries to store power. These batteries can hold 5,053 Watt-Hours of energy. There are also electronic systems to manage and send out this power.

How the Satellite Communicates

The main job of the satellite is to communicate. It has 24 Ku-band transponders. These are like special radios that receive and send signals. They are grouped to work together.

The satellite also has two large, unfoldable antennas. These antennas are 2.5 by 2.7 meters in size. They can be aimed to send signals where needed. They can work alone or together to speed up communications.

However, after launch, a power problem happened. This caused the communication system to degrade quickly. It is thought that the satellite lost almost half of its communication ability. Only about 12 of its transponders could still work. This, along with the normal wear of solar panels in space, has made the satellite's useful life shorter.

The satellite's signal strength is designed to be strong across all of South America.

Launching into Space

An Ariane 5 ECA rocket.

The Hispasat 74W-1 satellite was launched on March 22, 2014. The launch happened at 10:04 PM UTC. It was sent into space by an Ariane 5 ECA rocket. The launch site was the Guiana Space Center in Kourou, French Guiana. Another satellite, Astra 5B, was launched at the same time.

The Amazonas 4A (now Hispasat 74W-1) successfully reached a GEO orbit. This means it stays in a fixed position relative to Earth. Its orbit is about 35,807.6 km at its highest point (apogee) and 35,780.1 km at its lowest point (perigee). The orbit is very flat, with an inclination of only 0.1º. It takes 1,436.1 minutes to go around Earth.

The satellite was designed to cover all of South America. It first operated at 61º West longitude. Since 2017, it has moved to 73.9º West.

Power Problem After Launch

Soon after the satellite reached its orbit, it had a partial power failure. This meant it lost some of its abilities and its expected working life became shorter.

It was estimated that the satellite lost about half of its planned capabilities. Because it was hard to figure out why this happened and how bad it was, Hispasat and the insurance company started an investigation. This investigation will continue until the satellite stops working, which is expected around 2029.

This incident also led to changes in plans for another satellite, the Amazonas 4B.

Amazonas 4B Satellite

In 2012, Hispasat and Orbital Sciences Corporation had an agreement to build two new satellites: Amazonas 4A and Amazonas 4B. Both were planned to be at the 61 West longitude orbital position.

However, after the Amazonas 4A had its power problem in 2014, the plan changed. The Amazonas 4B project was cancelled. Instead, a new project called Amazonas 5 was started. This new satellite was built by a different company, SSL. The Amazonas 5 was designed to do what both the Amazonas 4A (before its power problem) and the Amazonas 4B were supposed to do. The Amazonas 5 successfully launched on September 11, 2017.

The exact plans for the Amazonas 4B are not fully known since it was cancelled early. But since it was planned with Amazonas 4A, it would likely have been similar. It probably would have used the GEO Star-2.4 or the newer GEO Star-3 as its main structure. It was also expected to work for about 15 years. Its engine would have been the same as Amazonas 4A's: the BT-4 from IHI Aerospace. The Amazonas 4B was planned to have 18 Ku-band transponders and two large antennas for communications.

See Also

In Spanish: Amazonas 4A para niños

• Hispasat
• Orbital Sciences Corporation