Venus Probe Surface Exploration

Exploration of Venus surface is very challenging due to the harsh atmospheric conditions and high temperature. The surface temperature of Venus is 450 °C to 500 °C. Therefore, if we design space probe using conventional technologies, it will be destroyed above 200 °C and we cannot get reliable results for our mission to explore Venus.

We need a probe that can survive and can be able to give us stable and reliable results by enduring high temperature for long operational time.

Many attempts were made to explore Venus by the last two centuries but unfortunately, never gain much success. So, our task now is to study the harsh environment and also operation of electronic devices in such environment to introduce better materials or techniques that can help in stable and reliable operation of that kind of devices in future.

In 2017, NASA’s Glenn Research centre has introduced a technology that can open new paths for Venus exploration in future.

The words from Phil Neudeck, leading engineer in NASA are stated below.

“With further technology development, such electronics could drastically improve Venus lander designs and mission concepts, enabling the first long-duration missions to the surface of Venus,”

Venus is from one of the four terrestrial planets in the solar system and second planet from the sun. In comparison of other planets, it completes one round trip in longer time and also in opposite direction to many other planets. After moon, it is the brightest object in the sky.

Atmosphere of Venus is very challenging and invites to do surface exploration. Atmospheric composition of Venus is approximately 96.5% of CO2, 3.5% of Nitrogen and traces of SO2, HCL and HF. In comparison to earth, the atmosphere of Venus is thicker and nitrogen contents are almost four times than that of Earth.

Our main goal is therefore to design a probe that will survive on the surface of Venus. So we would explore the condition of troposphere that extends from the surface to 65 km radius of the planet. Air density at surface is 67Kg/m3 and temperature at surface is 740k (467°C). The pressure at surface is 90 Earth atms. It can be implied that 99% of the atmosphere is of the 28km radius of the planet.

There are other factors also that should be defined, Venusian clouds which are composed of SO2 gas and droplets of H2SO4, thickest layer of this cloud exist within the troposphere (~48km).

Strategy adopted to encounter this problem is that firstly, a comprehensive study is done to observe the Venus environment and history of missions that were launched to explore Venus. Secondly, the list of problems is extracted, that cause failure in the operation of probe.

Let’s have a look on short history of failure of starting era space probe.

• Venera 3 was the first spacecraft that crash-landed on Venus in 1966.
• Venera 2 was failed due to overheating, shortly before completion of mission. And it was the sister craft of next version, that landed successfully.
• After that in 1967, Venera 4 was successful to return measurements taken from direct planet.
• Later on in 1969, the results were verified by Venera 5 and Venera 6.
• In 1970, Venera 7 managed to stay on Venus surface only for 23 minutes due to intolerance for high temperature.

The main problem for solution seekers is only the high temperature and harsh environment. In the next section of this report, different know techniques will be introduced and defined to encounter the problem and to propose the best available solutions in this regard.

High temperature components

• Physical sensors and pressure vessel for advanced thermal control
• High temperature electronics (Active and passive components)
• System for data acquisition
• Data processing and communication
• Accelerometer for sesimic activities
• Energy storage devices (Suitable at high temperature)

These components will help to prolong the operation by bearing the high temperature, but the most important part is the packaging materials, that will prolong the standard bearing capacity of components by shielding them from harsh environment and high temperature.

High temperature electronics packaging is the rising area that needs new materials and process that can to be helpful to shield the important circuits to carry on research work. The results of these materials should be reliable and also be able to focus temperature and life time requirements. Polymer and ceramic substrates are found to be helpful for this kind of electronics.

PCB’s are the most common type, used as packaging material. Variety of these materials are available according to their price range and temperature rating. According to some characteristics factors like degradation, adhesiveness, stress capacity and temperature range, their types are listed below.

• • Printed circuit board laminates

PCB sample description and life time prediction

• • Thin film polymide flexible circuits

Strength testing of circuit at high temprrature

Ceramic substrates poses higher capability than laminates. They are stable and do not face dielectric lose at higher temperature. Caution is the main factor in selecting these materials because they also face failure modes in conductor adhesion.

Widely available substrate in this category includes alumina substrate and are used in hybrid technology as low cost component.