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(14 September 2020 – Royal Astronomical Society) An international team of astronomers, led by Professor Jane Greaves of Cardiff University, today announced the discovery of a rare molecule – phosphine – in the clouds of Venus. On Earth, this gas is only made industrially, or by microbes that thrive in oxygen-free environments.

Astronomers have speculated for decades that high clouds on Venus could offer a home for microbes – floating free of the scorching surface, but still needing to tolerate very high acidity. The detection of phosphine molecules, which consist of hydrogen and phosphorus, could point to this extra-terrestrial ‘aerial’ life. The new discovery is described in a paper in Nature Astronomy.

The team first used the James Clerk Maxwell Telescope (JCMT) in Hawaii to detect the phosphine, and were then awarded time to follow up their discovery with 45 telescopes of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Both facilities observed Venus at a wavelength of about 1 millimetre, much longer than the human eye can see – only telescopes at high altitude can detect this wavelength effectively.

Artist’s impression of Venus, with an inset showing a representation of the phosphine molecules detected in the high cloud (courtesy: ESO / M. Kornmesser / L. Calçada & NASA / JPL / Caltech)

Professor Greaves says, “This was an experiment made out of pure curiosity, really – taking advantage of JCMT’s powerful technology, and thinking about future instruments. I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus’ spectrum, it was a shock!”

Naturally cautious about the initial findings, Greaves and her team were delighted to get three hours of time with the more sensitive ALMA observatory. Bad weather added a frustrating delay, but after six months of data processing, the discovery was confirmed.

Team member Dr Anita Richards, of the UK ALMA Regional Centre and the University of Manchester, adds: “To our great relief, the conditions were good at ALMA for follow-up observations while Venus was at a suitable angle to Earth. Processing the data was tricky, though, as ALMA isn’t usually looking for very subtle effects in very bright objects like Venus.”

Greaves adds: “In the end, we found that both observatories had seen the same thing – faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below.”

Professor Hideo Sagawa of Kyoto Sangyo University then used his models for the Venusian atmosphere to interpret the data, finding that phosphine is present but scarce – only about twenty molecules in every billion.

The astronomers then ran calculations to see if the phosphine could come from natural processes on Venus. They caution that some information is lacking – in fact, the only other study of phosphorus on Venus came from one lander experiment, carried by the Soviet Vega 2 mission in 1985.

Massachusetts Institute of Technology scientist Dr William Bains led the work on assessing natural ways to make phosphine. Some ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough of it. Natural sources were found to make at most one ten thousandth of the amount of phosphine that the telescopes saw.

To create the observed quantity of phosphine on Venus, terrestrial organisms would only need to work at about 10% of their maximum productivity, according to calculations by Dr Paul Rimmer of Cambridge University. Any microbes on Venus will likely be very different to their Earth cousins though, to survive in hyper-acidic conditions.

Earth bacteria can absorb phosphate minerals, add hydrogen, and ultimately expel phosphine gas. It costs them energy to do this, so why they do it is not clear. The phosphine could be just a waste product, but other scientists have suggested purposes like warding off rival bacteria.

Another MIT team-member, Dr Clara Sousa Silva, was also thinking about searching for phosphine as a ‘biosignature’ gas of non-oxygen-using life on planets around other stars, because normal chemistry makes so little of it.

She comments: “Finding phosphine on Venus was an unexpected bonus! The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment – but the clouds of Venus are almost entirely made of acid.”

Other possible biosignatures in the Solar System may exist, like methane on Mars and water venting from the icy moons Europa and Enceladus. On Venus, it has been suggested that dark streaks where ultraviolet light is absorbed could come from colonies of microbes. The Akatsuki spacecraft, launched by the Japanese space agency JAXA, is currently mapping these dark streaks to understand more about this “unknown ultraviolet absorber”.

The team believes their discovery is significant because they can rule out many alternative ways to make phosphine, but they acknowledge that confirming the presence of “life” needs a lot more work. Although the high clouds of Venus have temperatures up to a pleasant 30 degrees centigrade, they are incredibly acidic – around 90% sulphuric acid – posing major issues for microbes to survive there. Professor Sara Seager and Dr Janusz Petkowski, also both at MIT, are investigating how microbes could shield themselves inside droplets.

The team are now eagerly awaiting more telescope time, for example to establish whether the phosphine is in a relatively temperate part of the clouds, and to look for other gases associated with life. New space missions could also travel to our neighbouring planet, and sample the clouds in situ to further search for signs of life.

Professor Emma Bunce, President of the Royal Astronomical Society, congratulated the team on their work: “A key question in science is whether life exists beyond Earth, and the discovery by Professor Jane Greaves and her team is a key step forward in that quest. I’m particularly delighted to see UK scientists leading such an important breakthrough – something that makes a strong case for a return space mission to Venus.”

Science Minister Amanda Solloway said: “Venus has for decades captured the imagination of scientists and astronomers across the world.”

“This discovery is immensely exciting, helping us increase our understanding of the universe and even whether there could be life on Venus. I am incredibly proud that this fascinating detection was led by some of the UK’s leading scientists and engineers using state of the art facilities built on our own soil.”

Publication

The new work appears in “Phosphine Gas in the Cloud Decks of Venus”, Jane S. Greaves, Anita M. S. Richards, William Bains, Paul Rimmer, Hideo Sagawa, David L. Clements, Sara Seager, Janusz J. Petkowski, Clara Sousa-Silva, Sukrit Ranjan, Emily Drabek-Maunder, Helen J. Fraser, Annabel Cartwright, Ingo Mueller-Wodarg, Zhuchang Zhan, Per Friberg, Iain Coulson, E’lisa Lee and Jim Hoge, Nature Astronomy (2020).

Royal Astronomical Society

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,400 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

In 2020 the RAS is 200 years old. The Society is celebrating its bicentennial anniversary with a series of events around the UK, including public lectures, exhibitions, an organ recital, a pop-up planetarium, and the culmination of the RAS 200: Sky & Earth project.

James Clerk Maxwell Telescope

With a diameter of 15m (50 feet) the James Clerk Maxwell Telescope (JCMT) is the largest single dish astronomical telescope in the world designed specifically to operate in the submillimetre wavelength region of the electromagnetic spectrum. The JCMT is used to study our Solar System, interstellar and circumstellar dust and gas, evolved stars, and distant galaxies. It is situated in the science reserve of Maunakea, Hawai`i, at an altitude of 4092m (13,425 feet). The JCMT is operated by the East Asian Observatory on behalf of NAOJ; ASIAA; KASI; CAMS as well as the National Key R&D Program of China. Additional funding support is provided by the Science and Technology Facilities Council and participating universities in the UK and Canada.

ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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Space

MSSS To provide science cameras for Janus asteroid mission

MSSS To provide science cameras for Janus asteroid mission

(14 September 2020 – Malin Space Scence Systems) Malin Space Science Systems (MSSS) has been selected to provide the science payloads for the two Janus spacecraft.

Last week, Janus was approved by NASA to proceed with final design of the mission hardware, including the MSSS cameras (called “JCam”).

The Janus principal investigator is Dr. Daniel Scheeres of the University of Colorado Boulder. The spacecraft will be built and operated by Lockheed Martin. The two Janus spacecraft will be launched in August 2022 on the same Falcon Heavy rocket as NASA’s Psyche spacecraft. They will fly by two small binary asteroids, 1991 VH and 1996 FG3, in March-April 2026.

An ECAM-M50 (Monochrome) with NFOV (Narrow Field of View) lens (left), ECAM-IR3 (right), and ECAM-DVR4 (center). JCam will appear similar to this flight camera system from another program, as JCam will use the same electronics with different lenses. Pocket knife for scale. (courtesy: Malin Space Science Systems)

msss 2

A rendering of the two Janus spacecraft showing the position of JCam. The apertures of the JCam visible and thermal IR cameras project from the inside of the spacecraft along its upper right edge. For scale, the deployed solar array span is a little less than 9 feet. (courtesy: Lockheed Martin)

Each spacecraft will carry a JCam system built by MSSS. JCam consists of an ECAM M50 visible camera and an ECAM IR3 thermal infrared camera, with a DVR4 processing/storage unit with 16 GB of flash memory. It will obtain images of the asteroid targets and also be used for spacecraft navigation and pointing during the flybys. Each complete JCam system weighs less than 3.2 kg and has a maximum power draw of less than 14 watts. These combined visible and thermal infrared imaging capabilities will enable JCam to characterize the current morphology of 1991 VH and 1996 FG3 and to constrain their evolution.

ECAM systems are flight-proven and currently operating on several missions, including NASA’s OSIRIS-REx asteroid sample-return spacecraft and Northrop-Grumman’s MEV-1 and MEV-2 satellite servicing missions. The development and production of the two JCam systems for Janus is being done under contract to Lockheed Martin for $5.8 million.

MSSS is also building the visible multispectral imaging science cameras for the Psyche mission, which will launch with Janus. Psyche is a NASA Discovery mission, led by Dr. Lindy Elkins-Tanton of Arizona State University and managed by NASA’s Jet Propulsion Laboratory. It will arrive at the main belt asteroid Psyche in 2026.

Dr. Michael Ravine, JCam project manager at MSSS, said, “We are pleased that CU and Lockheed Martin selected MSSS to provide the payload for the two Janus spacecraft. JCam will return high resolution images of these asteroids and map the temperatures of their surfaces. It also means that a single launch will be carrying three spacecraft, going to three different targets, each with two MSSS cameras. That’s a first for us, maybe a first for anybody.”

MSSS has a long history of building and operating science instruments for NASA spacecraft, most recently five cameras on the Perseverance Mars rover, launched in August 2020 and scheduled to land on Mars in February 2021. We are also currently operating three cameras orbiting Mars on Mars Odyssey and Mars Reconnaissance Orbiter, four on the surface of Mars on the Curiosity rover, and one orbiting Jupiter on Juno.

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Industry gets working on Europe’s Hera planetary defence mission

Industry gets working on Europes Hera planetary defence mission

(15 September 2020 – ESA) Today ESA awarded a €129.4 million contract covering the detailed design, manufacturing and testing of Hera, the Agency’s first mission for planetary defence.

This ambitious mission will be Europe’s contribution to an international asteroid deflection effort, set to perform sustained exploration of a double asteroid system.

Hera – named after the Greek goddess of marriage – will be, along with NASA’s Double Asteroid Redirect Test (DART) spacecraft, humankind’s first probe to rendezvous with a binary asteroid system, a little understood class making up around 15% of all known asteroids.

Hera scans DART’s impact crater (courtesy: ESA)

The contract was signed today by Franco Ongaro, ESA Director of Technology, Engineering and Quality, and Marco Fuchs, CEO of Germany space company OHB, prime contractor of the Hera consortium. The signing took place at ESA’s ESOC centre in Germany, which will serve as mission control for the 2024-launched Hera.

Hera is the European contribution to an international planetary defence collaboration among European and US scientists called the Asteroid Impact & Deflection Assessment, AIDA. The DART spacecraft – due for launch in July 2021 – will first perform a kinetic impact on the smaller of the two bodies. Hera will follow-up with a detailed post-impact survey to turn this grand-scale experiment into a well-understood and repeatable asteroid deflection technique.

While doing so, the desk-sized Hera will also demonstrate multiple novel technologies, such as autonomous navigation around the asteroid – like modern driverless cars on Earth – while gathering crucial scientific data, to help scientists and future mission planners better understand asteroid compositions and structures.

Hera will also deploy Europe’s first ‘CubeSats’ (miniature satellites built up from 10 cm boxes) into deep space for close-up asteroid surveying, including the very first radar probe of an asteroid’s interior – using an updated version of the radar system carried on ESA’s Rosetta comet mission.

Due to launch in October 2024, Hera will travel to a binary asteroid system – the Didymos pair of near-Earth asteroids. The 780 m-diameter mountain-sized main body is orbited by a 160 m moon, formally christened ‘Dimorphos’ in June 2020, about the same size as the Great Pyramid of Giza.

DART’s kinetic impact into Dimorphos in September 2022 is expected to alter its orbit around Didymos as well as create a substantial crater. This moonlet asteroid will become unique, as the first celestial body to have its orbital and physical characteristics intentionally altered by human intervention. Hera will arrive at the Didymos system at the end of 2026, to perform at least six months of close-up study.

Hera’s mission control will be based at ESA’s ESOC centre in Darmstadt, Germany, also the home of ESA’s new Space Safety and Security programme, of which Hera is a part.

This contract signing covers the full Hera satellite development, integration and test, including its advanced guidance, navigation and control (GNC) system. Contracts for Hera’s two hosted CubeSats and relevant technology developments are already ongoing.

Hera’s European partners

The contract has been awarded to a consortium led by prime contractor OHB System AG in Bremen.

Of 17 ESA Member States contributing to Hera, Germany is in the forefront, tasked with the overall Hera spacecraft design and integration, main navigation cameras, tanks, thrusters, high-gain antenna, reaction wheels, and mass memory unit.

Italy is leading the mission’s power and propulsion subsystems, and is providing the deep-space transponder that will enable the mission’s radioscience experiment. In addition, Italy is leading the dust and mineral prospecting CubeSat, named after the late Andrea Milani, distinguished professor and leading asteroid scientist.

Belgium is developing Hera’s on-board computer and software, the brain of the spacecraft, plus its power conditioning and distribution unit – the heart of its electrical subsystem. It is also contributing to Hera’s Japanese-developed thermal imager and CubeSats operations center at ESA/ESEC.

Luxembourg is leading the radar-hosting ‘Juventas’ CubeSat and the inter-satellite communication system allowing the two Hera CubeSats to communicate with Earth through an innovative network using Hera as data relay.

Portugal and Romania are developing the laser altimeter which will provide crucial information for the autonomous navigation functions. In addition, Romania is developing the image processing unit, harness and the electrical test equipment (while also contributing to its GNC development).

The Czech Republic is responsible for the full satellite structure, payload software (to command the instruments), independent software validation and ground support equipment for pre-flight satellite testing. It is also providing components for Juventas’ low-frequency radar and data processing software on the second CubeSat.

And Spain is developing Hera’s advanced guidance, navigation and control system as well as the deep-space communication system. It is also providing the Juventas gravimeter instrument.

  • Austria is supporting with mission data analysis and processing
  • Denmark is contributing to the Juventas CubeSat and remote terminal unit
  • France is providing Juventas’ low-frequency radar, as well as star trackers and support to the CubeSats’ payload operations planning and close-proximity trajectories
  • Hungary is supporting scientific calibration of the cameras
  • The Netherlands is developing the new deep-space CubeSat deployment system and providing Hera’s Sun sensors
  • Switzerland is contributing with structural elements and mechanisms for the solar arrays
  • Finland is providing the second CubeSats’ multi-spectral imager and onboard equipment. It is also providing the data processing unit
  • Poland is contributing with Juventas’ low-frequency radar deployable antennas
  • Ireland is providing an innovative inertial measurement unit for the Hera spacecraft to support deep-space navigation
  • ESA Associate Member State Latvia is contributing a time-of-flight detector for the mission’s laser altimeter.

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Dust monitor to demonstrate pristine satellite launches

Dust monitor to demonstrate pristine satellite launches

(17 September 2020 – ESA) While on Earth, satellites are kept in immaculate cleanrooms to protect their instruments from harmful dust particles.

If those instruments fail to function properly in space, however, it could be because of particle contamination during launch. Now a British company has developed a device to identify whether this is the case.

Following successful trials of a prototype sensor, space-tech company XCAM is working with ESA to develop a flight-ready device that monitors dust contamination on payloads during and shortly after launch.

The device will provide data to demonstrate whether or not precious cargos – such as Earth-observing satellites – stay clean on their way into space.

XCAM’s prototype monitoring device (courtesy: ESA)

Payloads are protected from the elements within a secure capsule in the upper part of launcher called the fairing. Once outside the Earth’s atmosphere, the fairing separates, exposing its contents to space.

Cleanrooms protect spaceborne equipment from contamination during assembly, but vibrations and shocks during launch may shake up residues in the fairing that can affect how the payload operates.

Dust particles can contaminate optical surfaces, such as those found on Earth-observing satellites, as well as affecting the performance of sensitive mechanical equipment.

XCAM’s sensor keeps track of contamination remotely to provide continuous measurements in real-time.

The company is now working with ESA to develop a device that will be used in the fairing of the European Vega-C launcher. The gadget must be able to withstand the mechanical loads of launch such as acoustics and vibrations – and then survive in space for long enough to relay data back to Earth for analysis.

It will enable satellite launchers to provide evidence to their customers that payloads are kept spotless on their way into orbit.

“It was fantastic for XCAM to work on such an exciting project with ESA at the prototype stage, but to have been able to go beyond that, and win the contract to develop the flight qualified system is even better,” says Karen Holland, chief executive of XCAM.

“Following these achievements, XCAM has recently received several highly prestigious awards nominations for our work in the field of digital imaging systems. As a very small company of just 15 people, we are very pleased to be recognised by the awards judges.”

“Because of the very peculiar contamination mechanisms it presents, and the lack of monitoring inside the fairing, the launch phase is somewhat of an unresolved question for contamination engineers – which makes control of particulate very challenging,” says Riccardo Rampini, technical officer for the XCAM project.

“With the development of a novel sensor capable of operating before and during launch, which will provide real-time information on the particulate inside the fairing of a launcher, ESA will soon provide a solution to this problem.”

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