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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Biosignature | 5/6 | https://en.wikipedia.org/wiki/Biosignature | reference | science, encyclopedia | 2026-05-05T13:15:42.723741+00:00 | kb-cron |
===== ExoMars Orbiter ===== The 2016 ExoMars Trace Gas Orbiter (TGO) is a Mars telecommunications orbiter and atmospheric gas analyzer mission. It delivered the Schiaparelli EDM lander and then began to settle into its science orbit to map the sources of methane on Mars and other gases, and in doing so, will help select the landing site for the Rosalind Franklin rover to be launched in 2028. The primary objective of the Rosalind Franklin rover mission is the search for biosignatures on the surface and subsurface by using a drill able to collect samples down to a depth of 2 metres (6.6 ft), away from the destructive radiation that bathes the surface.
===== Mars 2020 =====
The Mars 2020 rover, which launched in 2020, is intended to investigate an astrobiologically relevant ancient environment on Mars, investigate its surface geological processes and history, including the assessment of its past habitability, the possibility of past life on Mars, and potential for preservation of biosignatures within accessible geological materials. In addition, it will cache the most interesting samples for possible future transport to Earth. In 2024, Perseverance found a rock, called Cheyava Falls, during its exploration of the Jezero Crater. The rover's instruments detected organic compounds within the rock. According to NASA, Cheyava Falls "possesses qualities that fit the definition of a possible indicator of ancient life". On 10 September 2025, NASA reported a "potential biosignature" finding in Cheyava Falls: organic-carbon–bearing mudstones hosting sub-millimetre nodules and millimetre-scale reaction fronts enriched in ferrous iron phosphate and iron sulfide, consistent with vivianite and greigite imply low-temperature, post-depositional redox reactions between organics and Fe–S–P minerals; these textures and chemistries qualify as potential biosignatures but requiring further study and sample return for confirmation. On Earth, vivianite is frequently found in sediments, peat bogs, and around decaying organic matter. Similarly, certain forms of microbial life on Earth can produce greigite. The same organic materials can be produced by non-biological processes which require "hot conditions" like volcanic activity; the rock location suggests that it was underwater, and there is no detected past volcanic activity in that region. If confirmed, this biosignature would mean that there were a microbial life on Mars around 3.5 billion years ago. According to geologist Michael Tice:
If the Cheyava Falls results ultimately do lead to the proof of ancient life on Mars ... that means two different planets hosted microbes getting their energy through the same means at about the same time in the distant past. That could suggest that early life learns how to survive in this way regardless of where it originated.
=== Venus ===
==== Atmosphere of Venus ==== The atmosphere of Venus continues to be investigated for potential biosignatures though abiotic processes have been put forward as explanations.
===== Ammonia in the Venusian Atmosphere =====
Ammonia (NH3) was first detected in the atmosphere by the bromophenol blue chemical sensor of Venera 8 in 1972. Ammonia is essential to life and is both a metabolic input and output, as such it has been explored as having strong potential as a biosignature. Pioneer Venus also detected substantial quantities of the gas. Of particular interest is that unlike the Martian atmosphere where conditions would suit ammonia's presence only transient trace amounts have been detected, on Venus with conditions less conducive to its presence it appears to somehow be replenished. A 2021 paper claimed that it could be a byproduct of life that is in turn providing a stable habitable environment for life to continue in the upper atmosphere. At least one paper puts forward a possible abiotic explanation, proposing that similar processes as nitrogen fixation in early Earth's atmosphere though caused by mantle oxidation due to the planet's water loss. Another has proposed that lightning could be producing it though whether Venus has lightning at all has been extensively debated.
===== Ozone in the Venusian Atmosphere ===== Ozone (O3) was first detected at concentrations of up to 1 ppm in the night side upper atmosphere by Venus Express in 2011. As a byproduct of living organisms this was once regarded as a candidate biosignature. Known since the 1970s to exists in trace amounts in the Martian atmosphere, Venus in comparison possesses a significant layer similar to but substantially less concentrated than Earth's. Photochemical processes, specifically dissociation of carbon dioxide (CO2) by sunlight, is now offered an explanation for its presence.
===== Phosphine in the Venusian Atmosphere ===== Phosphine (PH3) was first detected in 2020 by the James Clerk Maxwell Telescope and the Atacama Large Millimeter/submillimeter Array in trace amounts in the upper cloud deck. There was no known abiotic source for the quantities detected. Subsequent analysis and investigation between 2020 and 2015 indicated possible false detection, or a much lower concentration of 1 ppb. However in September 2024, the preliminary analysis of the JCMT-Venus data confirmed a concentration of 300 ppb at altitude 55 km. Further data processing is still needed to measure phosphine concentration deeper in the Venusian cloud deck.
==== Morning Star Missions to Venus ==== The Venus Life Finder is a planned mission to Venus, scheduled to launch no earlier than summer of 2026. The goal of these missions is to detecting potential organics, measure acidity, and determine the unknown UV absorber in the clouds of Venus.
=== Icy Moons ===
==== Missions ====
===== Europa Clipper =====
NASA's Europa Clipper probe is designed as a flyby mission to Jupiter's smallest Galilean moon, Europa. The mission launched in October 2024 and is set to reach Europa in April 2030, where it will investigate the potential for habitability on Europa. Europa is one of the best candidates for biosignature discovery in the Solar System because of the scientific consensus that it retains a subsurface ocean, with two to three times the volume of water on Earth. Evidence for this subsurface ocean includes: