A sampling of recent articles, videos, and images from space-related science news items (find previous roundups here):

** Asteroids and Comets

** OSIRIS-REx set to touch down briefly on Bennu – The Long Arm of NASA: The OSIRIS-REx Spacecraft Gets Ready To Grab An Asteroid Sample – IEEE Spectrum

Sixteen years after NASA’s OSIRIS-REx mission was first proposed and two years after the robotic spacecraft went into orbit around asteroid 101955 Bennu, mission team members are now counting down to the moment when it will descend to the surface, grab a sample—and then get out of there before anything can go wrong.

The sampling is set for next Tuesday, Oct. 20. If it works, it will be a first for the United States. (A Japanese probe is currently returning to Earth with samples from asteroid 162173 Ryugu.)

Though the mission plan has so far been executed almost flawlessly, an outsider might be forgiven for thinking there’s something a bit…well, counterintuitive about it. The spacecraft has no landing legs, because it will never actually land. Instead, the OSIRIS-REx spacecraft vaguely resembles an insect with a long snout—a honeybee, perhaps, hovering over a flower to pollinate it. The “snout” is actually an articulated arm with a 30.5 cm round collection chamber at the end. It’s called TAGSAM – short for Touch-And-Go Sample Acquisition Mechanism. You’ve doubtless heard the old expression, “I wouldn’t touch that with a 10-foot pole.” The TAGSAM arm is an 11-foot pole.

** Watch the event on NASA TV: Update: NASA to Broadcast OSIRIS-REx Activities | NASA

** A discussion of the OSIRIS-REx mission: NASA EZScience

The OSIRIS-REx spacecraft is scheduled to touch down on the asteroid Bennu on October 20, 2020, for its first sample collection attempt. To kick off the second season of #EZScience, NASA associate administrator for science Dr. Thomas Zurbuchen and National Air and Space Museum director Dr. Ellen Stofan discuss this exciting and innovative mission to return samples from an asteroid to Earth and the scientific opportunities it opens up.

** An interview with an OSIRIS REx mission scientist: Hotel Mars – John Batchelor Show/The Space Show – Dr. Harold C. Connolly talked about

…the OSIRIS REx mission to asteroid Bennu and the sample return from Bennu. We discussed landing at the Nightingale landing site on Bennu and why, the actual quantity of material being collected for sample return, material changes on the way back to Earth, instrumentation operational status, asteroid ejecta, Bennu collisions with asteroid material, Vesta rocks on Bennu, the expectation of finding organic prebiotic compounds in the sample and more.

** A simulation of the sampling maneuver using the SpaceMissions^tm app from BINARY SPACE (see posting here):

This video shows a simulation of the NASA probe OSIRIS-REx’s sample collection on Asteroid Bennu planned for October 20, 2020:

00:00 Approach Burn
00:09 Solar Panels folding back
00:23 Samples Collection Arm Deployment
01:06 Samples Collection
02:21 Samples Weighting
03:42 Storing Samples in Return Container
06:04 Solar Panels unfolding
06:15 Approach Trajectory

The above mentioned application is a 3D solar system and space missions simulator available in the Microsoft® Store: https://www.microsoft.com/store/apps/…

More about OSIRIS-REx and Bennu:

• Your Guide to the OSIRIS-REx sample collection | The Planetary Society
• Asteroid Bennu may have been home to ancient water flows | MIT Technology Review
• Ten Things to Know About Bennu – NASA

** Amateur astronomer spots a big NEO: Planetary Society Grant Winner Discovers Large Near-Earth Asteroid – The Planetary Society

An amateur astronomer has discovered a kilometer-wide asteroid that would create global devastation if it were to hit the Earth. Thankfully that won’t happen: the asteroid will miss our planet by 40 million kilometers as it passes on 10 September 2020, more than 100 times the distance between Earth and the Moon. But the fact that this relatively large near-Earth object, or NEO, wasn’t detected until now serves as a reminder that there’s much work to be done when it comes to defending our planet from dangerous asteroids.

Amateur astronomer Leonardo Amaral discovered the asteroid at the Campo dos Amarais observatory in Brazil. The Planetary Society in 2019 awarded Amaral an $8,500 grant to purchase a more stable telescope mount for better tracking and longer camera exposures. The Society’s Shoemaker NEO Grant program funds advanced amateur astronomers around the world who find, track, and characterize potentially dangerous space rocks. Much of this work follows up on asteroids discovered by large-scale sky surveys, providing observations crucial to orbit determination or asteroid characterization.

** A sizable and previously unknown asteroid recently passed by close by the Earth: School Bus-Size Asteroid to Safely Zoom Past Earth | NASA

Roughly 15 to 30 feet wide, the object will make its closest approach on Sept. 24.

A small near-Earth asteroid (or NEA) will briefly visit Earth’s neighborhood on Thursday, Sept. 24, zooming past at a distance of about 13,000 miles (22,000 kilometers) above our planet’s surface. The asteroid will make its close approach below the ring of geostationary satellites orbiting about 22,000 miles (36,000 kilometers) away from Earth.

Based on its brightness, scientists estimate that 2020 SW is roughly 15 to 30 feet (5 to 10 meters) wide – or about the size of a small school bus. Although it’s not on an impact trajectory with Earth, if it were, the space rock would almost certainly break up high in the atmosphere, becoming a bright meteor known as a fireball.

Venus

** Discovery of phosphine in the clouds of Venus ignites speculation that it is produced by microbial life. However, there are inorganic processes that could produce it as well. Possible Marker of Life Spotted on Venus | ESO

An international team of astronomers 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 needing to tolerate very high acidity. The detection of phosphine could point to such extra-terrestrial “aerial” life.

“When we got the first hints of phosphine in Venus’s spectrum, it was a shock!”, says team leader Jane Greaves of Cardiff University in the UK, who first spotted signs of phosphine in observations from the James Clerk Maxwell Telescope (JCMT), operated by the East Asian Observatory, in Hawaiʻi. Confirming their discovery required using 45 antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, a more sensitive telescope in which the European Southern Observatory (ESO) is a partner. 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 it effectively. 

The international team, which includes researchers from the UK, US and Japan, estimates that phosphine exists in Venus’s clouds at a small concentration, only about twenty molecules in every billion. Following their observations, they ran calculations to see whether these amounts could come from natural non-biological processes on the planet. Some ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough of it. These non-biological 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 (which consists of hydrogen and phosphorus) on Venus, terrestrial organisms would only need to work at about 10% of their maximum productivity, according to the team. Earth bacteria are known to make phosphine: they take up phosphate from minerals or biological material, add hydrogen, and ultimately expel phosphine. Any organisms on Venus will probably be very different to their Earth cousins, but they too could be the source of phosphine in the atmosphere.

More about the discovery:

• Did Scientists Just Find Life on Venus?… | The Planetary Society
• Could there be life on Venus? | The Planetary Society
• Hints of life renew interest in Venus, and a private mission could lead the way – Spaceflight Now
• How Much Life Would Be Required to Create the Phosphine Signal on Venus? – Universe Today
• Why the detection of phosphine in the clouds of Venus is a big deal – The Space Review

This finding greatly increases scientific and public interest in Venus, which has been visited by spacecraft far less often than Mars. The Venusian surface is a hell-scape with an atmospheric pressure over 90 times that of earth and temperatures close to 500 degrees Celsius. So the bare surface and thin atmosphere of Mars make it seem benign in comparison. However, there is the possibility of human habitats floating atop the thick Venusian atmosphere, though there would the challenge of dealing with the sulfuric acid present at such altitudes. Venus is similar to Earth in terms of gravity and so for human visitors it has at least this one advantage over the Red Planet, where gravity is about a third that of Earth’s.

** Interview with a member of the team that found evidence of phosphine in the Venusian clouds:

** BepiColombo spacecraft flies by Venus to adjust its orbit closer to Mercury, the target of its mission: BepiColombo flies by Venus en route to Mercury – ESA

The ESA-JAXA BepiColombo mission has completed the first of two Venus flybys needed to set it on course with the Solar System’s innermost planet, Mercury.

The closest approach of the flyby took place at 03:58 GMT (05:58 CEST) this morning at a distance of about 10 720 km from the planet’s surface.

The Venus flyby offered an opportunity to test the science instruments on the spacecraft and to investigate the cloudy planet:

Seven of the eleven science instruments onboard the European Mercury Planetary Orbiter, plus its radiation monitor, and three of five onboard the Japanese Mercury Magnetospheric Orbiter were active during the flyby. While the suite of sensors are designed to study the rocky, atmosphere-free environment at Mercury, the flyby offered a unique opportunity to collect valuable science data at Venus.

** The Parker Solar Probe flew by Venus, taking advantage of the planet’s gravity to adjust its orbit as well: Parker Solar Probe Speeds toward Record-Setting Close Approach to the Sun – Parker Solar Probe – Sept.25.2020

This weekend’s perihelion was set up by the probe’s third Venus flyby. On July 11, the spacecraft came within 518 miles above Venus’ surface — much lower than the previous two flybys but still well above Venus’ atmosphere — putting it on a path that brings it 3.25 million miles closer to the Sun than the last perihelion, on June 7. Mission Design and Navigation Manager Yanping Guo of APL noted that the gravity assist provided the mission’s largest orbital speed reduction since launch, trimming the spacecraft’s velocity by 8,438 miles per hour (13,579 kilometers per hour).

More at:

• Parker Solar Probe Mission Releases Science Data from Fourth Orbit – Parker Solar Probe
• Parker Solar Probe Prepares for Third Venus Flyby – Parker Solar Probe
• EPSC2020: Parker Solar Probe, Akatsuki and Earth-bound observers give rare top-to surface glimpse of Venus – Europlanet Society

Mars

Continue reading Space sciences roundup – Oct.19.2020 →