November 25, 2022
NASA’s Mars Science Laboratory (MSL) Curiosity rover first landed on Mars in August 2012. Since then, the rover has continuously collected a series of environmental readings that have surprised and delighted the mission’s scientists.
Over the past decade, Curiosity has traveled nearly 29 km, climbed 625 m, and explored its landing sites in Gale Crater and the base of Mount Sharp.
To this day, the mission’s first two-year goals have been dramatically exceeded and the rover’s instrumentation remains fully operational. Some of the mechanical parts are showing signs of wear, but the sensors are still working and providing unique data from Mars.
Here, Harri Heinonen, lead engineer on Vaisala’s sensor development team, and Professor Ari-Matti Harri, head of space observations and research at the Finnish Meteorological Institute (FMI), discuss why MSL Curiosity data is so important. This section explains.
Vaisala’s long history of supporting space exploration dates back to the 1950s. Vaisala converted radio theodolite frequencies to help track Sputnik 1, the world’s first artificial satellite.
Since 1992, Vaisala’s carbon dioxide, humidity, and temperature sensors have been used in life science experiments both on board the Space Shuttle and on the International Space Station.
FMI was responsible for building the humidity and pressure measurement equipment deployed on the MSL Curiosity Rover’s environmental measurement system (REMS). These sensors utilized Vaisala’s sensor heads, but FMI’s relationship with Vaisala predates the Curiosity project. Vaisala was founded in his 1936 by his Vaisala professor Wilho, who until 1948 he held a senior position at FMI.
Since then, Vaisala and FMI have collaborated on other interplanetary research missions, including the Cassini-Huygens spacecraft, which landed on Titan, Saturn’s largest moon, in 2005, and the Phoenix lander, which successfully landed on Mars in 2008. have collaborated on many projects.
Mars is dusty and cold, with a very thin atmosphere. The average temperature on Mars is about -60 degrees Celsius. However, daytime temperatures of +35°C have been recorded, with surface temperatures often rising to +20°C at noon at the equator and record lows of around -153°C at the poles. .
Known as the ‘red planet’, its surface contains large amounts of iron oxide, but the formation of this material is still a matter of debate. Mars has the highest mountains in the solar system (17 miles high – three times as high as Mount Everest) and the deepest and longest valleys.
Thanks to numerous explorations, there is strong evidence that billions of years ago Mars had a wetter, warmer and thicker atmosphere. The two were often called sister planets.
Two planets that are about the same size and rotate at similar tilts experience similar seasons, with day and night on Mars lasting about 24 1/2 hours of Earth time. However, Martian years are almost twice as long (687 Earth days) because they are farther from the Sun, so they orbit longer and travel slightly slower.
From a research perspective, Mars offers an opportunity to better understand how the Earth has evolved and how it may change in the future. For example, if Mars and Earth were both wet and warm billions of years ago, we need to understand why they followed different paths thereafter.
Mars is the most monitored planet after Earth, and given the similarities between the two planets, the data obtained so far have led scientists to apply existing Earth weather models to the Mars environment. is ready.
Continuous Mars monitoring will allow us to further refine these models to make Mars climate predictions more accurate.
Initially, the purpose of the MSL Curiosity mission was to make one-year environmental measurements on Mars. The study was designed to determine whether Mars could have supported microscopic life at some stage in its past. The conclusion was an overwhelming “YES!”
MSL Curiosity is working so well that NASA recently announced a three-year extension to the mission. During this next period, MSL Curiosity will climb to higher elevations and explore important sulfate-bearing layers that offer unique insights into the history of water on Mars.
In addition to cameras and radiation detectors, MSL Curiosity will also be equipped with instruments capable of performing chemical analysis on Mars. Alpha particle X-ray spectrometers measure the amount and type of chemical elements when they are near the surface of rocks and soils.
A ‘ChemCam’ laser, camera and spectrometer work together to identify the chemical and mineral composition of rocks and soils. The Chemical and Mineralogical Instruments perform chemical analyzes of rock samples in powder form, and the Sample Analysis Tools include three different instruments that search for and measure organic chemicals and light elements that may be relevant to life. It is
Chemical analyzes of rocks and dust are helping scientists better understand the history of Mars. But environmental measurements tell us about the current state of the planet.
The MSL Curiosity REMS, located about 1.5 m above the ground in the “neck” of the rover, contains Vaisala/FMI pressure and humidity sensors, as well as sensors for temperature, wind and UV measurements.
REMS operates at very low power and is designed to operate over a temperature range of -130°C to +70°C. Measurements are taken every hour on every Martian day or “sol” for at least 5 minutes. This data will enable mission scientists on Earth to provide daily and seasonal reports of weather conditions around the rover.
Space resistant sensor
It’s hard to imagine a more difficult situation than the sensors onboard NASA’s rovers experience during flight and surface exploration. In addition to huge fluctuations in temperature and pressure, sensors must also be able to withstand very high levels of vibration.
Vaisala’s sensor heads on board the Curiosity rover are essentially the same as those used routinely in nearly every industry on Earth, but Vaisala has adapted them to the very low ranges experienced on Mars. To do this, we made a slight modification to the pressure sensor. .
Both pressure and humidity sensor technologies were revolutionary when first launched, offering new levels of accuracy and long-term reliability. This is clearly an advantage for earth users, but it is essential when the nearest service his engineers are 400 million kilometers away from her.
At FMI, the process of developing measurement equipment included designing electronics, Faraday casing, encapsulation, casing, connectors, and dust protection. Naturally, the sensor was tested in every conceivable way before the final design was adopted, and the transducer was discreetly shipped to his REMS principal investigator at Spain’s Center for Astrobiology.
The humidity sensor features Vaisala’s HUMICAP technology. This is a capacitive thin-film polymer sensor consisting of a substrate with a film of polymer deposited between two electrodes.
As the humidity of the environment rises or falls, the polymer absorbs or releases water vapor. This changes the dielectric properties, which in turn change the capacitance of the sensor, which is measured and converted into a humidity reading.
Utilizing monocrystalline silicon material, Vaisala’s BAROCAP is a micromechanical pressure sensor that measures dimensional changes in silicon membranes. As the ambient pressure increases or decreases, the membrane bends, thereby increasing or decreasing the height of the vacuum gap inside the sensor.
The other side of the gap acts as an electrode, and as the distance between them changes, the sensor’s capacitance changes, which is measured and converted into a pressure reading.
A key feature of both sensors is their long-term stability and ability to withstand dust, chemicals, and harsh conditions. His 10-year performance of the sensors on board the MSL Curiosity suggests that as his REMS in the rover ages, the associated electronics are more likely to fail than the sensor head itself Vaisala’s sensor development No surprise for the team.
Find answers to basic questions
The benefits of space research mean different things to different people. For example, on purely scientific grounds, we humans are naturally curious and want to know more about our world and beyond.
But this knowledge does more than just satisfy curiosity. Help protect humanity and the environment we depend on.
If we can understand how planets form and evolve, we will be able to better predict and mitigate cosmic phenomena such as planetary destruction, asteroid collisions, mass extinctions, or conditions that make the Earth uninhabitable. increase.
Space research can help us better understand these issues. For some, Mars research may finally allow the movement of people between planets, if desired.
According to NASA, “Space exploration helps address fundamental questions about our position in space and the history of the solar system. It will help create new industries and promote peaceful ties with other countries.”
Mars is the most watched planet. As the Earth’s sister, it offers opportunities for comparative planetology. Around the world, hundreds of scientific papers have been published on this research, and given that the two planets have many features in common, many see Mars as a kind of scientific sand her box. I’m seeing For example, if scientists can discover why Mars and Earth developed in such different ways, it will hopefully lead to a better understanding of Earth’s future.
After discovering that conditions on Mars may have been favorable for life in the past, scientists investigated whether microscopic life existed at the time, suggesting how life first appeared on Earth. could lead to a better understanding of how it existed.
Since 1960, there have been 49 missions to Mars, about half of which have failed. Most of the failures occurred in the early days, but as scientists around the world learn more about space travel, technology, and the complexities associated with traveling to, orbiting, and landing on Mars, these experiences will continue to grow. It provided information for subsequent missions.
I’m looking forward to
Environmental monitoring data is needed to understand the planet’s climate, so the longevity of MSL Curiosity’s performance is a huge bonus, and the reliability of the rover’s onboard instrumentation will allow for a significant mission expansion. It means that
It’s important to understand that the MSL Curiosity mission is an important step in NASA’s Mars exploration program. Equipped with next-generation Vaisala technology in an FMI-developed instrument, the Perseverance Rover will land on Mars in February 2021. Look for traces of ancient life and collect rock and soil samples for possible return to Earth.
Additionally, the two rovers, which operate about 2,000 km apart, are laying the groundwork for the atmospheric observation network needed to better understand and predict Martian weather.
To fully understand the Martian climate and its history, we need to improve the spatial distribution of our measurements. Therefore, in the future, it will be important to be able to monitor multiple locations on the planet at the same time.
The data provided by the instruments on board the MSL Curiosity and Perseverance rovers may one day allow us to send humans to Mars.
But perhaps the greatest value of measured data is in helping us find answers to humanity’s biggest questions. How did life begin? Are we alone? What is the universe made of?