Phobos program

The Phobos program was an uncrewed space mission consisting of two probes launched by the Soviet Union to study Mars and its moon Phobos. The two spacecraft, named Phobos 1 and Phobos 2, were designed to gather important information about the Red Planet and its smaller moon.

Phobos 1 was launched on July 7, 1988, and Phobos 2 followed just five days later on July 12, 1988. Unfortunately, Phobos 1 stopped working during its journey to Mars. Phobos 2 made it into orbit around Mars and collected valuable data, but we lost contact with it before it could complete its final tasks.

These spacecraft were a new design, larger than previous ones used for exploring planets. Each weighed about 2,600 kilograms, or more than 6,000 kilograms with its equipment. They were launched using powerful Proton-K rockets. Many countries worked together on this program, sharing their skills and resources to help explore our cosmic neighbor.

Objectives

The Phobos missions aimed to learn more about space between planets, watch the Sun, and study the special conditions around Mars. They also wanted to explore Mars' surface and atmosphere, and to find out what the moon Phobos is made of.

The missions planned to look closely at the plasma around Mars and to make detailed atmospheric observations of the planet.

Spacecraft design

The main part of the spacecraft had a special round, sealed section for its electronic equipment. This section surrounded a tall, tube-like area where experiments were placed. Below these parts were four round tanks that held a special fuel called hydrazine. This fuel helped control the spacecraft’s movement and adjust its path after the main engine was released.

The spacecraft had 28 small engines for moving and balancing, plus more engines on its body and large solar panels that caught sunlight for power. It used a system to stay steady, guided by sensors that looked at the Sun and stars.

Phobos 1

Main article: Phobos 1

Phobos 1 was a space probe launched by the Soviet Union to study Mars and its moon Phobos. It worked well at first but stopped communicating on September 2, 1988. This happened because of a mistake in the software uploaded to the spacecraft. The mistake caused the probe to turn off its control system, which made it lose its position in space. Without this control, the probe could not keep its solar power panels facing the Sun, and its batteries ran out.

Phobos 2

Main article: Phobos 2

Phobos 2 was launched on July 12, 1988, and entered orbit around Mars on January 29, 1989. It worked well during its journey and when it reached Mars, collecting important information about the Sun, space between planets, Mars, and its moon Phobos. The probe studied Mars's surface and atmosphere and sent back 37 detailed pictures of Phobos. Sadly, contact was lost before it could drop a small lander onto Phobos as planned.

Systems and sensors

The Phobos probes had many tools to study Mars and its moon Phobos. They carried special telescopes to look at the Sun’s x-rays and ultraviolet light. There was also a neutron spectrometer and a radar tool called Grunt to examine the surface of Phobos.

The landers on the probes included an x-ray/alpha spectrometer to learn about the chemicals on Phobos’ surface, and a seismometer to understand its inside structure. The Phobos 2 probe’s infrared spectrometer (ISM) collected detailed images of Mars and Phobos, helping scientists make maps of their minerals and study Mars’ atmosphere. This tool was made at IAS and DESPA (Paris Observatory), with help from CNES.