February 22, 2021 — New video from NASA’s Mars 2020 Perseverance rover chronicles major milestones during the final minutes of its entry, descent, and landing (EDL) on the Red Planet on Feb. 18 as the spacecraft plummeted, parachuted, and rocketed toward the surface of Mars. A microphone on the rover also has provided the first audio recording of sounds from Mars.
From the moment of parachute inflation, the camera system covers the entirety of the descent process, showing some of the rover’s intense ride to Mars’ Jezero Crater. The footage from high-definition cameras aboard the spacecraft starts 7 miles (11 kilometers) above the surface, showing the supersonic deployment of the most massive parachute ever sent to another world, and ends with the rover’s touchdown in the crater.
NASA’s Mars 2020 Perseverance mission attempting to land the agency’s fifth rover on the Red Planet. Engineers at NASA’s Jet Propulsion Laboratory in Southern California, where the mission is managed, have confirmed that the spacecraft is healthy and on target to touch down in Jezero Crater at around 3:55 p.m. EST on Feb. 18, 2021.
“Perseverance is NASA’s most ambitious Mars rover mission yet, focused scientifically on finding out whether there was ever any life on Mars in the past,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “To answer this question, the landing team will have its hands full getting us to Jezero Crater – the most challenging Martian terrain ever targeted for a landing.”
Jezero is a basin where scientists believe an ancient river flowed into a lake and deposited sediments in a fan shape known as a delta. Scientists think the environment here was likely to have preserved signs of any life that gained a foothold billions of years ago – but Jezero also has steep cliffs, sand dunes, and boulder fields. Landing on Mars is difficult – only about 50% of all previous Mars landing attempts have succeeded – and these geological features make it even more so. The Perseverance team is building on lessons from previous touchdowns and employing new technologies that enable the spacecraft to target its landing site more accurately and avoid hazards autonomously.
“The Perseverance team is putting the final touches on the complex choreography required to land in Jezero Crater,” said Jennifer Trosper, deputy project manager for the mission at JPL. “No Mars landing is guaranteed, but we have been preparing a decade to put this rover’s wheels down on the surface of Mars and get to work.” You will get to watch the drama of Perseverance’s entry, descent, and landing (EDL) – the riskiest portion of the rover’s mission that some engineers call the “seven minutes of terror” – live on NASA TV. Commentary starts at 2:15 p.m. EST on Feb. 18. Engineers expect to receive notice of key milestones for landing at the estimated times below. (Because of the distance the signals have to travel from Mars to Earth, these events actually take place on Mars 11 minutes, 22 seconds earlier than what is noted here.)
Cruise stage separation: The part of the spacecraft that has been flying Perseverance – with NASA’s Ingenuity Mars Helicopter attached to its belly – through space for the last six-and-a-half months will separate from the entry capsule at about 3:38 p.m. EST.
Atmospheric entry: The spacecraft is expected to hit the top of the Martian atmosphere traveling at about 12,100 mph (19,500 kph) at 3:48 p.m. EST.
Peak heating: Friction from the atmosphere will heat up the bottom of the spacecraft to temperatures as high as about 2,370 degrees Fahrenheit (about 1,300 degrees Celsius) at 3:49 p.m. EST.
Parachute deployment: The spacecraft will deploy its parachute at supersonic speed at around 3:52 p.m. EST. The exact deployment time is based on the new Range Trigger technology, which improves the precision of the spacecraft’s ability to hit a landing target.
Heat shield separation: The protective bottom of the entry capsule will detach about 20 seconds after the parachute deployment. This allows the rover to use a radar to determine how far it is from the ground and employ its Terrain-Relative Navigation technology to find a safe landing site.
Back shell separation: The back half of the entry capsule that is fastened to the parachute will separate from the rover and its “jetpack” (known as the descent stage) at 3:54 p.m. EST. The jetpack will use retrorockets to slow down and fly to the landing site.
Touchdown: The spacecraft’s descent stage, using the sky crane maneuver, will lower the rover down to the surface on nylon tethers. The rover is expected to touch down on the surface of Mars at human walking speed (about 1.7 mph, or 2.7 kph) at around 3:55 p.m. EST.
The International Gemini Observatory, a program of the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab), is seen testing a new laser which is a critical component in the telescope’s adaptive optics system. Adaptive optics utilize artificial guide stars, produced by a laser, as a reference when compensating for distortions caused by turbulence in the Earth’s atmosphere. The result is ultra-sharp images that rival the view from space. Laser commissioning activities required pointing at specific parts of the sky designed to both test and calibrate the state-of-the-art laser. This image is created from a stack of images that reveal the Earth’s rotation and the colors inherent in the images. The laser is pointing in the direction of Polaris, or the North Star (Hokupa‘a in Hawaiian). The green glow near the horizon is due to airglow from oxygen high in the Earth’s atmosphere.
This illustration shows the events that occur in the final minutes of the nearly seven-month journey that NASA’s Perseverance rover takes to Mars. Hundreds of critical events must execute perfectly and exactly on time for the rover to land on Mars safely on Feb. 18, 2021.
Entry, Descent, and Landing, or “EDL,” begins when the spacecraft reaches the top of the Martian atmosphere, traveling nearly 12,500 mph (20,000 kph). It ends about seven minutes later, with Perseverance stationary on the Martian surface. Perseverance handles everything on its own during this process. It takes more than 11 minutes to get a radio signal back from Mars, so by the time the mission team hears that the spacecraft has entered the atmosphere, in reality, the rover is already on the ground.
NASA’s Jet Propulsion Laboratory in Southern California built and will manage operations of the Mars 2020 Perseverance rover for NASA.
On December 21, 2020 Jupiter and Saturn will appear closer in our sky than they have since the year 1623 — only .10º apart. By way of comparison, Earth’s Moon covers about .50º on average! In fact, the two planets will have so little visual separation that they may appear as one bright “star” in our evening sky. As with many objects we see in our night sky, planets Jupiter and Saturn will only appear to be near to each other; they will will be physically separated by about 456 million miles.
Here’s why the planets will appear so close in our sky:
Viewed from Earth and looking out toward Jupiter and Saturn we see the planets as if they were in the same orbit — like watching runners in their separate lanes as one overtakes the other. Viewed from “above” we can see that the planets remain well apart.
As we drop lower and closer to the orbital plane it becomes more difficult to separate Jupiter and Saturn until, on December 21, 2020, we won’t be able to see them as discrete objects without the use of a telescope!
While the previous extremely close conjunction took place in 1623, Jupiter and Saturn were too close to the Sun to be observed. The last time they could actually be seen so close together was even longer ago: on March 4, 1226. Great Conjunctions take place just short of 20 years apart and most are not so close as this year’s — the next will take place on October 31, 2040, when Jupiter and Saturn will be separated by 1.1º which will be close, but not so amazing as 2020.
If you plan to take a look, you’ll need clear skies (of course!) and you’ll need to be timely — the planetary pair will become visible low in the southwestern sky with the fading twilight and will set in the west by 7:20 PM, December 21. To see the individual planets during their close encounter will require a telescope — a small one will do — or a decent telephoto lens on a camera mounted on a tripod. Given good optics and clear skies, viewers will be able to make out the Galilean Moons of Jupiter and, perhaps spy Titan, Saturn’s brightest moon.
Before and after the 21st, Jupiter and Saturn will appear close together as they first approach, and then recede from the conjunction, continuing to move along their orbital paths. The historic astronomical event will be one night and one night only in our lifetimes. Clear skies, please!
There will be a lunar eclipse the morning of November 30, 2020 but you may not want to get out of a warm bed to view it — it will be fairly “weak.” This month’s eclipse, viewable in its entirely from Northern Ohio (given clear skies) is of the penumbral variety and will not display the eerie colors that make total lunar eclipses so exciting.
A penumbral lunar eclipse occurs when the Full Moon passes through the shady outer circle — the penumbra — of Earth’s shadow streaming out into space. Careful observers will note how most of Moon dims slightly with a sliver of a brighter southern edge and a darker northern area. During a total lunar eclipse, the Full Moon passes fully through the darkest portion of Earth’s shadow, the umbra, and is illuminated by the colors of the globe’s sunrises and sunsets. Again, that won’t happen this time.
Most of Monday’s event is quite subtle and takes a long time, many won’t even notice the difference. If you want to see this eclipse at its best, even photogenic, view it only around maximum. The penumbral eclipse begins [P1] at 2:32 AM, reaches its Greatest eclipse (you may note northern darkening) at 4:52 AM, and the event ends [P4] at 6:53 AM when Moon completes its emergence from Earth’s shade.
The next total lunar eclipse — the type that features coppery-red colors at its peak — will take place May 26, 2021; unfortunately, that event will reach its maximum as Moon sets locally. The next total lunar eclipse that we might see in its entirety will take place May 16, 2022 and that should be a doozie!
The night of October 2 – 3 will see a brilliant pairing of lights, a conjunction, in our night sky. Earth’s Moon and planet Mars will shine close together — only a smidgen over a degree apart — in the southeast. As viewed from the Hiram, Ohio area, Moon and Mars will be nearest each other at 12:18 AM EDT. Don’t worry if you can’t stay up, the two will be a beautiful pair to behold all night long.
Our Moon will be a day past Full and in its Waning Gibbous phase, so it will be round and bright. Mars, while too distant to be seen as a disc by the unaided eye, is nearing an unusually close approach to Earth during its opposition and will shine like a coppery star. Mars will be nearest to Earth, at 62 million kilometers (38,525,014 miles) distant, on October 6 and it won’t be that close again until 2035.
Opposition refers to a time in their orbits when Mars (or another planet) is opposite the Earth from the Sun — around that time is when the two bodies, on concentric racetrack orbits around the Sun, pass each other and are at their closest and brightest.
At 6:24 AM EDT, September 30, a surprising light appeared in the predawn sky over Hiram — an extremely bright fireball meteor flared overhead! A fireball meteor is a meteor that appears brighter than the planet Venus. Reports of the flare were made by startled observers over eastern Ohio and western Pennsylvania.
Hiram College is home to a NASA All-Sky Fireball Network camera system that watches for bright meteors every clear night. Recorded events are uploaded to NASA for analysis which aids in assessing threats to spacecraft by high-velocity solar system debris.
Hiram College has been home to the NASA all-sky camera since 2013. The camera sits atop one of the buildings on the college campus and is maintained in cooperation with NASA’s Meteoroid Environment Office.
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. Confirming the presence of life, however, will require much more work.
“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 millimeter, 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.
While the discovery of phosphine in Venus’s clouds came as a surprise, the researchers are confident in their detection. “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,” says team member Anita Richards of the UK ALMA Regional Centre and the University of Manchester. “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,” adds Greaves, who led the study published today in Nature Astronomy.
Another team member, Clara Sousa Silva of the Massachusetts Institute of Technology in the US, has investigated 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.”
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 Celsius, they are incredibly acidic — around 90% sulfuric acid — posing major issues for any microbes trying to survive there.
ESO astronomer and ALMA European Operations Manager Leonardo Testi, who did not participate in the new study, says: “The non-biological production of phosphine on Venus is excluded by our current understanding of phosphine chemistry in rocky planets’ atmospheres. Confirming the existence of life on Venus’s atmosphere would be a major breakthrough for astrobiology; thus, it is essential to follow-up on this exciting result with theoretical and observational studies to exclude the possibility that phosphine on rocky planets may also have a chemical origin different than on Earth.”
More observations of Venus and of rocky planets outside our Solar System, including with ESO’s forthcoming Extremely Large Telescope, may help gather clues on how phosphine can originate on them and contribute to the search for signs of life beyond Earth.