Astronomy and space news summarized by Don Lynn from NASA and other sources

Ingenuity – The Mars helicopter Ingenuity completed its planned five test flights. The final one of these included landing at a new site that it had not touched before (though it took images of the site during its previous flight), and climbing to a record altitude of 33 feet. Its flights must be within about three-fifths of a mile of the rover Perseverance, because the tiny radio in the helicopter has a limited range to send flight data and images after each flight. The rover then relays the images and data on to Earth, usually via Mars orbiters. New flight plans are sent from Earth through the rover to the helicopter, also due to radio limitations. The entire flight plan has to be aboard the copter’s computer, because radio updates from Earth take 17 minutes to reach Mars, traveling at the speed of light (and radio). Ingenuity can fly only about every three days because it has to recharge its batteries from its tiny solar panel after every flight. The original plan was to complete just five test flights before the rover moved out of range of Ingenuity, in order to pursue the rover mission of finding and analyzing samples of Martian soil and rocks to eventually return to Earth. But based on what the rover is seeing near the landing site, it’s exploring and gathering activities are now scheduled to not leave the helicopter behind for a few more months. This means that Ingenuity’s mission of test flights has been extended for up to three more months. It will now run tests, dubbed “operations demonstrations,” of how it can map in stereo the terrain ahead of the rover and image places the rover can’t reach.

Chinese Mars Rover – China became the second country, after the United States, to successfully land a spacecraft on Mars. All the Soviet/Russian landers, two European landers and several of the American landers failed. Nine U.S. landers succeeded, beginning with Viking in 1976. Landing on Mars is a difficult endeavor. The Chinese craft is a combination lander and rover, the latter named Zhurong. A mission of at least three months is planned for Zhurong, where it will search for water and ice using a ground-penetrating radar, zap rocks with a laser to determine their chemistry, measure magnetic field, report the Martian weather and take pictures. The orbiting part of the mission remains circling above the planet. The mission name is Tianwen-1.

Chinese Space Station – In May, China launched the first of three planned space station modules. This is that country’s third space station. The new module is named Tianhe, meaning Harmony of the Heavens. A three-month stay at the space station by taikonauts, the term for Chinese astronauts, is scheduled to begin in June. The expected life of the station is at least ten years.

Exoplanet With Large Orbit – A team of astronomers led by scientists at Leiden University imaged a gas giant planet orbiting a Sun-like star. Most exoplanets are lost in the glare of their star, but this planet is orbiting at 110 times as far from its star as the Earth is from the Sun, allowing it to escape its star’s glare. Only about 15 exoplanets have been imaged, out of the more than 4000 known. The star, known as YSES 2 (named after the Young Suns Exoplanet Survey that found it), is only 14 million years old. It is 360 light-years away in the constellation Musca. The planet has six times the mass of Jupiter. There should not be enough material to form such a big planet this far from its star, so astronomers are trying to figure out how it could have moved into such a distant orbit, particularly since it has had less than 14 million years to move. The image was made using the SPHERE instrument on the Very Large Telescope in Chile.

Exoplanet Hydroxyl – For the first time, hydroxyl has been detected spectroscopically in the atmosphere of an exoplanet by an international collaboration of astronomers led by a researcher from the Astrobiology Center at Queen’s University Belfast. The planet is known as WASP-33b, which is a gas giant orbiting so close to its star that it reaches a temperature of about 4,500 degrees Fahrenheit. It is thought that the heat breaks hydrogen atoms loose from water molecules to leave hydroxyl. Though the planet’s atmosphere cannot be resolved from its star’s glare, the spectroscopic lines of the atmosphere were distinguished by their Doppler shift due to the planet’s orbital motion.

Star Growth Rate – A team at the University of Texas at Austin, using the Hubble Space Telescope observed in ultraviolet the gas falling onto a planet still forming, known as PDS 70b. This is the first time observations have shown the rate at which material is being added to a forming planet. The current rate is 1/100 Jupiter mass per million years. Yet the average over the planet’s entire life so far of five million years is about one Jupiter mass per million years. This shows that the rate of growth has dropped drastically, indicating that the planet is nearing the end of its formation period. The planet and its star are 370 light-years away in Centaurus. Its orbit about its orange dwarf star is about the size of Uranus’s orbit.

Galaxy Wake – New observations led by astronomers at the Center for Astrophysics, Harvard & Smithsonian show that there is a pile-up of stars in two areas near the disk of our Milky Way galaxy. This matches computer simulations of the effects of the past motion of the satellite galaxy known as the Large Magellanic Cloud (LMC) as it falls toward the Milky Way. The simulation showed that dark matter bunches up gravitationally as the LMC falls, and then stars pile up in the dark matter concentrations. One of these areas is a sort of wake behind the motion of the LMC, and the other is a zone just above the central bulge of the Milky Way. The piled-up stars were found in data from the Gaia and WISE space telescopes.

Venus Rotation – Fifteen years of radar observations of Venus have been analyzed by researchers at the University of California, Los Angeles to determine the planet’s sidereal rotation rate. Past work on that rotation rate, based on spacecraft data and radar, resulted in differing values. Sidereal rotation is measured in relation to the fixed stars, and normally changes extremely slowly. For example, Earth’s sidereal rotation period varies by a fraction of a millisecond from year to year, primarily due to weather effects. The new study concluded that Venus’s rotation changes by as much as 20 minutes from one of its days to the next. This presents a problem for future spacecraft missions that wish to land at a particular place on Venus, as that place may have rotated miles away due to changes in the rotation period. The thick Venusian atmosphere and high winds likely account for the changes in the planet’s rotation. Also, 20 minutes of variation is smaller than it might at first seem, relatively speaking, because one should compare it as a percentage against the length of a Venusian day, which lasts about 243 Earth days. The same radar data allowed calculation of the tilt of the Venusian rotation axis, the period of precession of the axis, and roughly the size of the planet’s core. Resulting numbers are 243.0226 Earth days per sidereal rotation, 2.6392 degrees tilt, 29,000 Earth years precession period, and somewhat under 2,200 miles core diameter. The data was insufficient to determine if the core is solid or liquid however.

Venus Ionosphere – The Parker Solar Probe’s trajectory is designed to flyby Venus every year or so to use gravity slingshots around the planet to successively bend its orbit closer and closer to the Sun. The Venus flyby last June was the nearest yet to the planet, bringing the spacecraft so close that it flew through the planet’s ionosphere for seven minutes. Radio data taken by the probe allowed calculation by scientists at NASA’s Goddard Space Flight Center of the density of the charged particles in Venus’s ionosphere. As expected, since the Sun is near the low point in its eleven-year activity cycle, the charged particle density is much lower than previous measures made many years ago by Venus orbiter spacecraft when the Sun was closer to its peak of activity.

Comet Nickel – A pair of astronomers at Jagiellonian University in Poland found nickel in the ultraviolet spectrum of the interstellar comet Borisov. An independent group of astronomers at the University of Liège in Belgium, were also studying comet spectra and found nickel, as well as iron, in about 20 comets. Finding nickel in comets before this had been fairly rare. Some of these comets were quite far from the Sun at the time the nickel appeared, so there could not be much heat involved in freeing the nickel from the comet nucleus. One theory is that the nickel existed in the nuclei as a constituent in compounds that have very low vaporizing temperatures, but more work is needed to fully explain this nickel.

Asteroid Sample – NASA’s OSIRIS-REx spacecraft successfully fired its rocket engine for seven minutes to leave orbit about the asteroid Bennu and head on a trajectory that will bring it back to Earth. It will parachute a canister containing a sample of asteroid dirt and rock into a desolate stretch of Utah desert on September 24, 2023. The sample is estimated to be about nine ounces; the sample retrieval was considered a success if anything over two ounces was captured. NASA is considering whether to extend OSIRIS-REx’s mission beyond the Earth flyby in order to visit another near-Earth object. 

Space Tourism – Blue Origin, the space flight company founded by Jeff Bezos, the owner of Amazon, scheduled their first flight of tourists to space by July 20, launching from west Texas. The last of the six seats was auctioned off. The New Shepard spacecraft (named after astronaut Alan Shepard) launches and lands vertically, barely exceeding the altitude of 62 miles that is considered the edge of outer space. The flight will last about 11 minutes, with several of those minutes experiencing weightlessness.

Michael Collins – The country, and indeed the world, has lost a space hero with the death of Michael Collins at age 90. He was the crew member who remained in orbit about the Moon on the Apollo 11 mission, while Armstrong and Aldrin became the first humans to set foot on the Moon. His other spaceflight was Gemini 10, during which docking and other abilities were developed to be used on Moon missions. He was the fourth human to perform a spacewalk. After retiring as an astronaut, he headed the National Air and Space Museum. His autobiography, Carrying the Fire, is considered by many to be the best book by any astronaut.

NASA Administrator – NASA Administrator Bill Nelson was sworn in as head of the agency on May 3. The position is a political appointment and changes whenever the U.S. President changes. Nelson had previously served as a member of both the U.S. House of Representatives and Senate, representing Florida, where most of NASA’s launches take place. In 1986 he was a payload specialist astronaut on a Space Shuttle mission, though it was a “congress courtesy” flight, in part as a reward for his support of NASA in Congress. He received a strong confirmation vote from both parties in the Senate, which bodes well toward cooperation between NASA and Congress, which controls NASA’s budget. Nelson has expressed strong support for putting astronauts back on the Moon with the Artemis program, and for continued use by NASA of commercially developed rockets, including those of SpaceX and Blue Origin.