Nepedia
Back to Discover
Advanced Reader
🚀

Pioneer 11

space Maturity 7-9 Next article →

Pioneer 11, also known as Pioneer G, was a groundbreaking robotic space probe.

Pioneer G (Pioneer 11) launch
Pioneer G (Pioneer 11) launch

It was launched by NASA on April 5, 1973, from Cape Canaveral, Florida. The mission was designed to explore the outer Solar System. It aimed to study the asteroid belt and the solar wind. Scientists also wanted to investigate the environments around Jupiter and Saturn. This probe was a vital precursor to the famous Voyager program. It helped pave the way for future deep-space exploration.

To function in the deep reaches of space, the probe required a steady power source.

NASM-NASM2016-00091
NASM-NASM2016-00091

It used four SNAP-19 radioisotope thermoelectric generators, or RTGs. These devices convert heat into electricity to power the spacecraft's systems. At launch, the RTGs provided 155 watts of power. By the time the probe reached Jupiter, this had decayed to 140 watts. The spacecraft required 100 watts to operate all its systems. This power was delivered via two long trusses positioned 120 degrees apart. This distance kept the radiation from the RTGs away from the sensitive scientific instruments.

Managing a spacecraft so far away requires complex engineering and precise control.

Pioneer 10-11 - P50 - fx
Pioneer 10-11 - P50 - fx

The spacecraft had a total mass of 259 kilograms. Its orientation was maintained by six hydrazine monopropellant thrusters. These thrusters controlled the spin-rate, forward thrust, and overall attitude. To stay pointed correctly, the probe used Sun sensors and a star sensor to track the star Canopus. Communication with Earth happened via the S-band radio frequency. The probe used a high-gain antenna to transmit data. A convolutional encoder helped correct errors in the data received by the Deep Space Network on Earth.

The mission was planned through several specific scientific stages and objectives.

Pioneer 10-11 - P51b - fx
Pioneer 10-11 - P51b - fx

Initially, the goal was to explore the interplanetary medium beyond Mars. Scientists also needed to assess if the asteroid belt posed a hazard to future missions. Once the mission moved toward the outer planets, the goals became much more specific. For Saturn, the probe was tasked with mapping the magnetic field and its intensity. It also needed to measure the temperature of Saturn's atmosphere and its moon, Titan. Researchers wanted to study the ionosphere and the thermal structure of the atmosphere using infrared observations.

History shows that Pioneer 11 was a true pioneer for planetary science.

Pioneer 10-11 - P52a - fx
Pioneer 10-11 - P52a - fx

The mission was approved in February 1969 as part of the Pioneer program. It was built by the company TRW and managed by NASA Ames Research Center. Pioneer 11 was the first probe to encounter Saturn. It was also the second probe to fly through the asteroid belt. In 1974, the probe underwent a significant maneuver to change its trajectory. This 42-minute engine burn increased its speed by 230 km/h. This change allowed the probe to fly past Jupiter and eventually reach Saturn.

The encounters with the giant planets provided immense amounts of data.

Pioneer 10-11 - P54 - fx
Pioneer 10-11 - P54 - fx

In late 1974, the probe flew past Jupiter and captured images of the Great Red Spot. It also used a gravity assist from Jupiter to gain the velocity needed for Saturn. On September 1, 1979, Pioneer 11 reached Saturn. It purposefully flew through the Saturn ring plane to check for dangerous particles. This was done to protect the upcoming Voyager spacecraft. During this encounter, the probe discovered a new small moon and found that Titan was too cold for life. It also captured unique images where the rings appeared dark instead of bright.

As the years passed, the probe continued its journey into the unknown.

Pioneer 10-11 - P52b - fx
Pioneer 10-11 - P52b - fx

On February 25, 1990, Pioneer 11 became the fourth human-made object to pass the orbit of the planets. It eventually achieved escape velocity, meaning it could leave the Solar System entirely. However, the probe's power eventually ran out. By 1995, it could no longer power its scientific detectors. The last routine contact occurred on September 30, 1995. The last good engineering data was received on November 24, 1995. Today, the probe remains a durable explorer traveling through deep space.

660 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (16)
File:NASM-NASM2016-00091.jpg
NASM-NASM2016-00091.jpg
File:Pioneer 10-11 - P50 - fx.jpg
Pioneer 10-11 - P50 - fx.jpg
File:Pioneer 10-11 - P51b - fx.jpg
Pioneer 10-11 - P51b - fx.jpg
File:Pioneer 10-11 - P52a - fx.jpg
Pioneer 10-11 - P52a - fx.jpg
File:Pioneer 10-11 - P52b - fx.jpg
Pioneer 10-11 - P52b - fx.jpg
File:Pioneer 10-11 - p53 - fx.jpg
Pioneer 10-11 - p53 - fx.jpg
File:Pioneer 10-11 - P54 - fx.jpg
Pioneer 10-11 - P54 - fx.jpg
File:Pioneer 10-11 - P56 - fx.jpg
Pioneer 10-11 - P56 - fx.jpg
File:Pioneer 10-11 - P55b - fx.jpg
Pioneer 10-11 - P55b - fx.jpg
File:Pioneer 10-11 - P57a - fx.jpg
Pioneer 10-11 - P57a - fx.jpg
File:Pioneer 10-11 - P60 - fx.jpg
Pioneer 10-11 - P60 - fx.jpg
File:P58 - fx.jpg
P58 - fx.jpg

+ 4 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.