Category Archives: Uncategorized

A Martian Helicopter

When I first heard about the Martian helicopter I dismissed the idea as folly. How would you even get the thing in the air? Well the Martian atmosphere is very thin, but the gravity on Mars is just over a third of what it is here on Earth (Mars and Earth comparison). Here gravity is 9.81 m/s2 and on Mars it is 3.6 m/s2

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So the helicopter is reality and will be launching with NASA’s Mars 2020 rover in July 2020. Can you imagine? Flying a helicopter millions of miles away with a multiple minute time delay to account for the time the control signals get to Mars and back, ranging from 4 to 24 minutes is going to be a big challenge.

Hubble Sees Asteroid Coming Apart

NASA: A small asteroid has been caught in the process of spinning so fast it’s throwing off material, according to new data from NASA’s Hubble Space Telescope and other observatories.

Images from Hubble show two narrow, comet-like tails of dusty debris streaming from the asteroid (6478) Gault. Each tail represents an episode in which the asteroid gently shed its material — key evidence that Gault is beginning to come apart.

Discovered in 1988, the 2.5-mile-wide (4-kilometer-wide) asteroid has been observed repeatedly, but the debris tails are the first evidence of disintegration. Gault is located 214 million miles (344 million kilometers) from the Sun. Of the roughly 800,000 known asteroids between Mars and Jupiter, astronomers estimate that this type of event in the asteroid belt is rare, occurring roughly once a year.

Watching an asteroid become unglued gives astronomers the opportunity to study the makeup of these space rocks without sending a spacecraft to sample them.

“We didn’t have to go to Gault,” explained Olivier Hainaut of the European Southern Observatory in Germany, a member of the Gault observing team. “We just had to look at the image of the streamers, and we can see all of the dust grains well-sorted by size. All the large grains (about the size of sand particles) are close to the object and the smallest grains (about the size of flour grains) are the farthest away because they are being pushed fastest by pressure from sunlight.”  

Gault is only the second asteroid whose disintegration has been strongly linked to a process known as a YORP effect. (YORP stands for “Yarkovsky–O’Keefe–Radzievskii–Paddack,” the names of four scientists who contributed to the concept.) When sunlight heats an asteroid, infrared radiation escaping from its warmed surface carries off angular momentum as well as heat. This process creates a tiny torque that can cause the asteroid to continually spin faster. When the resulting centrifugal force starts to overcome gravity, the asteroid’s surface becomes unstable, and landslides may send dust and rubble drifting into space at a couple miles per hour, or the speed of a strolling human. The researchers estimate that Gault could have been slowly spinning up for more than 100 million years.

Piecing together Gault’s recent activity is an astronomical forensics investigation involving telescopes and astronomers around the world. All-sky surveys, ground-based telescopes, and space-based facilities like the Hubble Space Telescope pooled their efforts to make this discovery possible.

The initial clue was the fortuitous detection of the first debris tail, observed on Jan. 5, 2019, by the NASA-funded Asteroid Terrestrial-Impact Last Alert System (ATLAS) telescope in Hawaii. The tail also turned up in archival data from December 2018 from ATLAS and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) telescopes in Hawaii. In mid-January, a second shorter tail was spied by the Canada–France–Hawaii Telescope in Hawaii and the Isaac Newton Telescope in Spain, as well as by other observers. An analysis of both tails suggests the two dust events occurred around Oct. 28 and Dec. 30, 2018. 

Follow-up observations with the William Herschel Telescope and ESA’s (European Space Agency) Optical Ground Station in La Palma and Tenerife, Spain, and the Himalayan Chandra Telescope in India measured a two-hour rotation period for the object, close to the critical speed at which a loose “rubble-pile” asteroid begins to break up.

“Gault is the best ‘smoking gun’ example of a fast rotator right at the two-hour limit,” said team member Jan Kleyna of the University of Hawaii in Honolulu.

An analysis of the asteroid’s surrounding environment by Hubble revealed no signs of more widely distributed debris, which rules out the possibility of a collision with another asteroid causing the outbursts. 

The asteroid’s narrow streamers suggest that the dust was released in short bursts, lasting anywhere from a few hours to a few days. These sudden events puffed away enough debris to make a “dirt ball” approximately 500 feet (150 meters) across if compacted together. The tails will begin fading away in a few months as the dust disperses into interplanetary space. 

Based on observations by the Canada–France–Hawaii Telescope, the astronomers estimate that the longer tail stretches over half a million miles (800,000 kilometers) and is roughly 3,000 miles (4,800 kilometers) wide. The shorter tail is about a quarter as long.

Only a couple of dozen active asteroids have been found so far. Astronomers may now have the capability to detect many more of them because of the enhanced survey capabilities of observatories such as Pan-STARRS and ATLAS, which scan the entire sky. “Asteroids such as Gault cannot escape detection anymore,” Hainaut said. “That means that all these asteroids that start misbehaving get caught.”

The researchers hope to monitor Gault for more dust events.

The team’s results have been accepted for publication by The Astrophysical Journal Letters.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C. 

Credits: NASA, ESA, K. Meech and J. Kleyna (University of Hawaii), and O. Hainaut (European Southern Observatory)


Hubble Looks at Neptune

NASA: In 1989, NASA’s Voyager 2 zipped past Neptune—its final planetary target before speeding to the outer limits of the solar system. It was the first time a spacecraft had visited the remote world. As the craft zoomed by, it snapped pictures of two giant storms brewing in Neptune’s southern hemisphere. Scientists dubbed the storms “The Great Dark Spot” and “Dark Spot 2.”

Just five years later, in 1994, NASA’s Hubble Space Telescope took sharp images of Neptune from Earth’s distance of 2.7 billion miles (4.3 billion kilometers). Scientists were eager to get another look at the storms. Instead, Hubble’s photos revealed that both the Earth-sized Great Dark Spot and the smaller Dark Spot 2 had vanished.

“It was certainly a surprise,” recalls Amy Simon, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We were used to looking at Jupiter’s Great Red Spot, which presumably had been there for more than a hundred years.” Planetary scientists immediately began constructing computer simulations in order to understand the Great Dark Spot’s mysterious disappearance.

Now part of the Outer Planet Atmospheres Legacy (OPAL) project, Simon and her colleagues are beginning to answer these questions. Thanks to images captured by Hubble, the team has not only witnessed a storm’s formation for the first time but developed constraints that pinpoint the frequency and duration of the storm systems.

The Birth of a Storm

In 2015, the OPAL team began a yearly mission to analyze images of Neptune captured by Hubble and detected a small dark spot in the southern hemisphere. Each year since, Simon and her colleagues have viewed the planet and monitored the storm as it dissipated. In 2018, a new dark spot emerged, hovering at 23 degrees north latitude.

“We were so busy tracking this smaller storm from 2015, that we weren’t necessarily expecting to see another big one so soon,” says Simon about the storm, which is similar in size to the Great Dark Spot. “That was a pleasant surprise. Every time we get new images from Hubble, something is different than what we expected.”

What’s more, the storm’s birth was caught on camera. While analyzing Hubble images of Neptune taken from 2015 to 2017, the team discovered that several small, white clouds formed in the region where the most recent dark spot would later appear. They published their findings March 25 in the journal Geophysical Research Letters.

The high-altitude clouds are made up of methane ice crystals, which give them their characteristic bright, white appearance. These companion clouds are thought to hover above the storms, similar to the way that lenticular clouds cap tall mountains on Earth. Their presence several years before a new storm was spotted suggests that dark spots may originate much deeper in the atmosphere than previously thought.

“In the same way a terrestrial Earth satellite would watch Earth’s weather, we observe the weather on Neptune,” says Glenn Orton, a planetary scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who also serves on the OPAL project. Just as hurricanes are tracked on Earth, Hubble’s images revealed the dark spot’s meandering path. In a span of nearly 20 hours, the storm drifted westward, moving slightly slower than Neptune’s high-speed winds.

But these Neptunian storms are different from the cyclones we see on Earth or Jupiter. So are the wind patterns that propel them. Similar to the rails that keep errant bowling balls from bounding into the gutters, thin bands of wind currents on Jupiter keep the Great Red Spot on a set path. On Neptune, wind currents operate in much wider bands around the planet, allowing storms like the Great Dark Spot to slowly drift across latitudes. The storms typically hover between westward equatorial wind jets and eastward-blowing currents in the higher latitudes before strong winds pull them apart.

Still more observations are needed. “We want to be able to study how the winds are changing over time,” says Simon.

Average Lifespan?

Simon is also part of a team of scientists led by undergraduate student Andrew Hsu of the University of California, Berkeley, who pinpointed how long these storms last and how frequently they occur.

They suspect that new storms crop up on Neptune every four to six years. Each storm may last up to six years, though two-year lifespans were more likely, according to findings published March 25 in the Astronomical Journal.

A total of six storm systems have been spotted since scientists first set their sights on Neptune. Voyager 2 identified two storms in 1989. Since Hubble launched in 1990, it has viewed four more of these storms.

In addition to analyzing data collected by Hubble and Voyager 2, the team ran computer simulations that charted a total of 8,000 dark spots swirling across the icy planet. When matched to 256 archival images, these simulations revealed that Hubble likely would have spotted approximately 70 percent of the simulated storms that occurred over the course of a year and roughly 85 to 95 percent of storms with a two-year lifespan.

Still, Questions Swirl.

Conditions on Neptune are still largely a mystery. Planetary scientists hope to next study changes in the shape of the vortex and wind speed in the storms. “We have never directly measured winds within Neptune’s dark vortices, but we estimate the wind speeds are in the ballpark of 328 feet (100 meters) per second, quite similar to wind speeds within Jupiter’s Great Red Spot,” says Michael Wong, a planetary scientist at the University of California, Berkeley. More frequent observations using the Hubble telescope, he notes, will help paint a clearer picture of how storm systems on Neptune evolve.

Simon says that discoveries on Neptune will have implications for those studying exoplanets in our galaxy that are similar in size to the ice giants. “If you study the exoplanets and you want to understand how they work, you really need to understand our planets first,” says Simon. “We have so little information on Uranus and Neptune.”

All agree that these recent findings have spurred a desire to track our furthest major planetary neighbor in even greater detail. “The more you know, the more you realize you don’t know,” says Orton.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C. The researchers used data acquired from the Hubble Space Telescope associated with the OPAL program and archived by the STScI.

For more information about Hubble, visit: www.nasa.gov/hubbleBy Jennifer Leman

NASA’s Goddard Space Flight Center, Greenbelt, Md.


NASA/ESA/GSFC/JPL

ExoMars Parachute in the Oven

This is one of those strange coincidences. Just a few days ago, Tuesday, I was having a conversation with a friend of mine about the precautions of bacteria from Earth going to other places other than home. “Well they do nothing because bacteria would die in outer-space.” NOT SO I countered. Bacteria can indeed live in “outer-space”, citing bacteria found on the outside of the International Space Station.

Today I saw this from ESA dealing with such issue on the ExoMars parachute and I knew I should have wagered on it (LOL).

ESA: A technician places a nearly 70 kg parachute designed for ESA and Roscosmos’s ExoMars 2020 mission inside the dry heater steriliser of the Agency’s Life, Physical Sciences and Life Support Laboratory, based in its Netherlands technical centre.

Mars is a potential abode of past and perhaps even present-day life. Accordingly, international planetary protection regulations require any mission sent to the Red Planet to undergo rigorous sterilisation, to prevent terrestrial microbes from piggybacking their way there.

The Lab’s Alan Dowson explains: “This is the ‘qualification model’ of the 35-m diameter main parachute for ExoMars 2020, basically a test version which allows us to finalise our sterilisation procedures ahead of the flight model chute’s arrival.

“This version has been threaded with thermal sensors, allowing us to see how long it takes to reach the required sterilisation temperature in all parts of the folded parachute, even in the hardest to heat points. Our target was to sterilise at 125 °C for 35 hours and 26 minutes, and the oven took about 44 hours to reach that temperature to begin with.”

The oven is part of the Lab’s 35 sq. m ‘ISO Class 1’ cleanroom, one of the cleanest places in Europe. All the cleanroom’s air passes through a two-stage filter system. Anyone entering the chamber has to gown up in a much more rigorous way than a hospital surgeon, before passing through an air shower to remove any remaining contaminants.

“If you imagine our clean room as being as big as the entire Earth’s atmosphere, then its allowable contamination would be equal to a single hot air balloon,” adds Alan. “Our ISO 1 rating means we have less than 10 dust particles measuring a tenth of one millionth of a metre in diameter per cubic metre of air.”

The mostly nylon and Kevlar parachute, packed into an 80-cm diameter donut-shaped unit, was delivered by Italy’s Arescosmo company. This qualification model will now be sent back there for testing, to ensure this sterilisation process causes no change to the parachute’s material properties.

Alan explains: “We will receive the parachute flight model later this spring for the same sterilisation process – identical to this version, except without any thermal sensors.”

ExoMars’s smaller first stage 15-m diameter parachute has already gone through sterilisation using the oven. This is the parachute that opens during initial, supersonic atmospheric entry, with the second, larger chute opening once the mission has been slowed to subsonic velocity.

The Lab has also tackled a variety of ExoMars instruments and subsystems, but this second stage subsonic parachute is the single largest item to be sterilised. The sterilisation process aims to reduce the overall mission ‘bioburden’ to a 10 thousandth of its original level.

Image: ESA–M. Cowan

InSight’s Mole Stopped

The InSight lander has started to deploy the probe it is to hammer into the planet but has run into a problem. It sounds like the probe only managed to get about 30 cm / 11 in before it stopped.

Hopefully the mission team can get it a bit deeper, best not take any chances yet and of course they are not.

NASA — NASA’s Mars InSight lander has a probe designed to dig up to 16 feet (5 meters) below the surface and measure heat coming from inside the planet. After beginning to hammer itself into the soil on Thursday, Feb. 28, the 16-inch-long (40-centimeter-long) probe — part of an instrument called the Heat and Physical Properties Package, or HP3 — got about three-fourths of the way out of its housing structure before stopping. No significant progress was seen after a second bout of hammering on Saturday, March 2. Data suggests the probe, known as a “mole,” is at a 15-degree tilt.

Scientists suspect it hit a rock or some gravel. The team had hoped there would be relatively few rocks below ground, given how few appear on the surface beside the lander. Even so, the mole was designed to push small rocks aside or wend its way around them. The instrument, which was provided for InSight by the German Aerospace Center (DLR), did so repeatedly during testing before InSight launched.

“The team has decided to pause the hammering for now to allow the situation to be analyzed more closely and jointly come up with strategies for overcoming the obstacle,” HPPrincipal Investigator Tilman Spohn of DLR wrote in a blog post. He added that the team wants to hold off from further hammering for about two weeks.

Data show that the probe itself continues to function as expected: After heating by 50 degrees Fahrenheit (28 degrees Celsius), it measures how quickly that heat dissipates in the soil. This property, known as thermal conductivity, helps calibrate sensors embedded in a tether trailing from the back of the mole. Once the mole is deep enough, these tether sensors can measure Mars’ natural heat coming from inside the planet, which is generated by radioactive materials decaying and energy left over from Mars’ formation.

The team will be conducting further heating tests this week to measure the thermal conductivity of the upper surface. They will also use a radiometer on InSight’s deck to measure temperature changes on the surface. Mars’ moon Phobos will pass in front of the Sun several times this week; like a cloud passing overhead, the eclipse will darken and cool the ground around InSight.

Image: NASA/JPL-Caltech/DLR

Space X Launch

SpaceX will be launching (hopefully) from Cape Canaveral at 20:45 ET / 01:45 UT (22 Feb).

Stop by and watch here, if you can’t watch there will be replays after the launch.

If there is not a launch due to some issue, the next opportunity is a few minutes less than 24 hours later.

The Current Solar Cycle

I’ve seen a few mentions about how we are in a new solar cycle. Well not quite so fast, the demarcation line is not distinct and it is just a wee bit too early to tell. There are some good signs to be sure, but at the same time the solar disc as been spotless for 8-days straight and 22 out of the 40 days so far this year.

So we are at solar minimum to be sure and this is probably not a “grand solar minimum” especially given the positive signs we are seeing since the “grand solar minimum” is a prolonged period, much longer than what we’ve seen so far. Basically at this point I consider such claims to be click-bait.

Here’s a little more about the solar-cycle from Michel van Biezen:

InSight Update

Happy days people, we have an update from the InSight Mars Lander mission. Sounds like the seismometer might start getting good data soon.

NASA – For the past several weeks, NASA’s InSight lander has been making adjustments to the seismometer it set on the Martian surface on Dec. 19. Now it’s reached another milestone by placing a domed shield over the seismometer to help the instrument collect accurate data. The seismometer will give scientists their first look at the deep interior of the Red Planet, helping them understand how it and other rocky planets are formed.

The Wind and Thermal Shield helps protect the supersensitive instrument from being shaken by passing winds, which can add “noise” to its data. The dome’s aerodynamic shape causes the wind to press it toward the planet’s surface, ensuring it won’t flip over. A skirt made of chain mail and thermal blankets rings the bottom, allowing it to settle easily over any rocks, though there are few at InSight’s location.

An even bigger concern for InSight’s seismometer — called the Seismic Experiment for Interior Structure (SEIS) — is temperature change, which can expand and contract metal springs and other parts inside the seismometer. Where InSight landed, temperatures fluctuate by about 170 degrees Fahrenheit (94 degrees Celsius) over the course of a Martian day, or sol.

“Temperature is one of our biggest bugaboos,” said InSight Principal Investigator Bruce Banerdt of NASA’s Jet Propulsion Laboratory in Pasadena, California. JPL leads the InSight mission and built the Wind and Thermal Shield. “Think of the shield as putting a cozy over your food on a table. It keeps SEIS from warming up too much during the day or cooling off too much at night. In general, we want to keep the temperature as steady as possible.”

On Earth, seismometers are often buried about four feet (1.2 meters) underground in vaults, which helps keep the temperature stable. InSight can’t build a vault on Mars, so the mission relies on several measures to protect its seismometer. The shield is the first line of defense.

A second line of defense is SEIS itself, which is specially engineered to correct for wild temperature swings on the Martian surface. The seismometer was built so that as some parts expand and contract, others do so in the opposite direction to partially cancel those effects. Additionally, the instrument is vacuum-sealed in a titanium sphere that insulates its sensitive insides and reduces the influence of temperature.

But even that isn’t quite enough. The sphere is enclosed within yet another insulating container — a copper-colored hexagonal box visible during SEIS’s deployment. The walls of this box are honeycombed with cells that trap air and keep it from moving. Mars provides an excellent gas for this insulation: Its thin atmosphere is primarily composed of carbon dioxide, which at low pressure is especially slow to conduct heat.

With these three insulating barriers, SEIS is well-protected from thermal “noise” seeping into the data and masking the seismic waves that InSight’s team wants to study. Finally, most additional interference from the Martian environment can be detected by InSight’s weather sensors, then filtered out by mission scientists.

With the seismometer on the ground and covered, InSight’s team is readying for its next step: deploying the heat flow probe, called the Heat Flow and Physical Properties Package (HP3), onto the Martian surface. That’s expected to happen next week.

Image: NASA/JPL-Caltech