Japan to build wooden satellites - cut space junk.
Japan developing wooden satellites to cut space junk - BBC News
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Japan to build wooden satellites - cut space junk.
Japan developing wooden satellites to cut space junk - BBC News
From that article:
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. Elon Musk's SpaceX has already launched more than 900 Starlink satellites and has plans to deploy thousands more.
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Space junk travels at an incredibly fast speed of more than 22,300 mph, so can have cause considerable damagElon Musk's SpaceX has already launched more than 900 Starlink satellites and has plans to deploy thousands more.
Space junk travels at an incredibly fast speed of more than 22,300 mph, so can have cause considerable damage to any objects it hits.
In 2006 a tiny piece of space junk collided with the International Space Station, taking a chip out of the heavily reinforced window.e to any objects it hits.
In 2006 a tiny piece of space junk collided with the International Space Station, taking a chip out of the heavily reinforced window.
yikes!
NASA detects FM signals from Jupiter's moon Ganymede for the first time
The National Aeronautics and Space Administration (NASA) has detected FM radio signals from Jupiter's moon Ganymede for the first time.
However, the US space agency clarified that it is a ''natural function'' rather than a sign of extraterrestrial life, that is the existence of aliens.
The signals from Ganymede originated from electrons due to electromagnetic fields. The process causes electrons within to whirl and oscillate much slower than their spin rate.
As a result, all electromagnetic and radio waves get amplified and are picked up by spacecraft hovering in space. These electrons also create auroras in the ultraviolet spectrum.
NASA will extend two of its planetary discovery missions including its Juno which detected the "cyclotron maser instability (CMI)" from Ganymede in the first place.
"Electrons spiralling in Jupiter's magnetic field are thought to be the cause of the radio noise we hear," NASA said in a statement.
Like Earth, Ganymede has a liquid iron core that generates a magnetic field, though Ganymede’s field is embedded within Jupiter’s magnetic field. That sets up an interesting dynamic with telltale visuals – twin bands of glowing aurora around Ganymede’s northern and southern polar regions. As Jupiter rotates, its magnetic field shifts, causing Ganymede’s aurora to rock.
NASA Planetary Science Division Director Jim Green called the finding “an astounding demonstration.” “They developed a new approach to look inside a planetary body with a telescope,” Green said.
Ganymede boasts a lot of water, perhaps 25 times the volume of Earth’s oceans. Its oceans are estimated to be about 500 miles (800 km) deep.
Ganymede is one of five moons in the solar system thought to have oceans hidden below icy surfaces. Two other moons, Europa and Callisto, orbit the big gas planet Jupiter. The moons Titan and Enceladus circle the ringed gas planet Saturn.
NASA detects FM signals from Jupiter's moon Ganymede for the first time, Science News | wionews.com
is a noise floor which is there to shield us from communicate with other civilizations...:)Quote:
Originally Posted by misskit
The ISS is getting an upgrade for their solar arrays. They have been deteriorating over time. The new arrays are flexible. They are sent up in rolls in the trunk of Dragon supply capsules and are rolled out on top of the existing panels. That way the mechanics that keep the arrays pointed towards the sun can still be used.
New Solar Arrays to Power NASA’s International Space Station Research | NASA
This is one of 6 panels that will be deployed. 3 of these go into the trunk of 1 Dragon, so they will have 2 flights to launch them. The interior of the Dragon is stil available for other cargo that goes into the inside of the ISS. The new arrays are smaller than the old ones but still provide more power.
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As the International Space Station orbits Earth, its four pairs of solar arrays soak up the sun’s energy to provide electrical power for the numerous research and science investigations conducted every day, as well as the continued operations of the orbiting platform. The space station is the springboard to NASA's Artemis missions to the Moon, a platform to test advanced technologies for human exploration of deep space and future mission to Mars. NASA also has opened the space station for business and commercial activities, including private astronauts missions.
Designed for a 15-year service life, the solar arrays have been operating continuously since the first pair was deployed in December 2000, with additional array pairs delivered in September 2006, June 2007, and March 2009. The first pair of solar arrays has now provided continuous electrical power to the station for more than 20 years as more modules were added and dozens of crews tackled thousands of scientific experiments and continued operations through hundreds of spacewalks, cargo missions, and more.
Though they are functioning well, the current solar arrays are showing signs of degradation, as expected. To ensure a sufficient power supply is maintained for NASA’s exploration technology demonstrations for Artemis and beyond as well as utilization and commercialization, NASA will be augmenting six of the eight existing power channels of the space station with new solar arrays. Boeing, NASA’s prime contractor for space station operations, its subsidiary Spectrolab, and major supplier Deployable Space Systems (DSS) will provide the new arrays. The combination of the eight original, larger arrays, and the smaller, more efficient new arrays will restore the power generation of each augmented array to approximately the amount generated when the original arrays were first installed, providing a 20% to 30% increase in power for space station research and operations.
The new solar arrays will be a larger version of the Roll-Out Solar Array (ROSA) technology that successfully demonstrated the mechanical capabilities of solar array deployment during its test on the space station in June 2017.
The new solar arrays will be positioned in front of six of the current arrays, and will use the existing sun tracking, power distribution, and channelization. This approach is similar to the one used to upgrade the station’s external television cameras to high definition, using the existing power and control mechanisms.
The new arrays will shade slightly over half of the length of the existing arrays and will be connected to the same power system to augment the existing supply. The eight current arrays are currently capable of generating up to 160 kilowatts of power during orbital daytime, about half of which is stored in the station’s batteries for use while the station is not in sunlight. Each new solar array will produce more than 20 kilowatts of electricity, eventually totaling 120 kilowatts (120,000 watts) of augmented power during orbital daytime. In addition, the remaining uncovered solar array pair and partially uncovered original arrays will continue to generate approximately 95 kilowatts of power for a total of up to 215 kilowatts (215,000 watts) of power available to support station operations at completion. For comparison, an active computer and monitor may use up to 270 watts, and a small refrigerator uses about 725 watts.
The solar arrays will be delivered to the International Space Station in pairs in the unpressurized trunk of the SpaceX Dragon cargo spacecraft during three resupply missions starting in 2021, when the second pair of current arrays reaches the 15th year of its design life. The installation of each solar array will require two spacewalks: one to prepare the worksite with a modification kit and another to install the new solar array.
NASA signed a modification to the ISS Vehicle Sustaining Engineering contract with Boeing to provide the six new solar arrays. Doing so provides the International Space Station with enough power to maintain normal operations and ensure adequate power for future opportunities in low-Earth orbit, whether for NASA and its international partners or commercial companies.
Last Updated: Jan. 11, 2021
Editor: Mark Garcia
The roll out mechanism has been tested on a small test device on the ISS already. Rolling out was successful. Rolling them back in so the array could be discarded into the atmosphere failed. Not a big problem.
Roll-Out Solar Array Experiment (ROSA) Deploys on International Space Station - YouTube
This is how a well used rocket booster looks like before its fifth flight. Not shiny white like the one shot boosters their competition still launches.
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Same booster after its fifth flight and successful landing on a drone ship. Landing just short of Cuba on a polar orbit.
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Takeovers, a great thread and thank you for your continuing input, i have followed it with great interest over the years.
There is a a lot going on recently and the future of space exploration looks busy and exciting. A lot to look forward to with a slight worry that countries could turn things nasty, let hope things don't pan out like on Earth.
Besides the almighty explosion it looked pretty successful. :)
13 minutes :42 seconds
Can you tell me which bit to skip to?
They have eliminated the problem that caused the failure last time. A new problem popped up. I think they will need a little time until they can do the next test. I am slightly disappointed, but not too much.
It may have been a failure of that one engine that did not restart. They are still in a phase of continuing improvement of the Raptor engine. Raptor like every aspect of this rocket is revolutionary new. They will need time to fix all the problems. They can afford losing prototypes. At present they are building them faster than they can test and destroy them.
Skip to 5:20.Quote:
Originally Posted by TheRealKW
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Originally Posted by TheRealKW
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Didn't it damage the one next to it?
If it did, they will just do a bit of welding, maybe swap out an engine or two, and it will be as good as new!:)
:)Quote:
Originally Posted by qwerty
They had an engine ready to install on tuesday morning. When they got launch permit, they took the engine away. SN10 has no engines installed yet. Lots of speculation about it. SN5 and 6 had their engines installed on the pad after tests. With SN8 they changed the procedure and installed the engines in the factory area. Same with SN9. But then they moved SN10 to the launch site without engines. My best guess is they need the highbay building empty to proceed with building SN15 and the first booster BN1.
We don't know exactly, but it seems SN7.2, the test tank and SN10 are not damaged. Looking forward to the next tests of SN7.2, a test to destruction. They have reduced the tank wall from 4mm to 3mm steel and need to prove that the tank is still strong enough for man rated margins.
I get into trouble sometimes in the space forums. They use new speak and want to see human rated. But I don't use new speak. Saw a great comment by a woman recently. She said I am not a female engineer, I am an engineer. Worked once with a woman coworker. She is not only a great engineer, she is a great woman too.
SpaceX Starlink launch L17 has been delayed by minor problems with the launch vehicle and a lot of weather related delays. It is now scheduled for tomorrow Feb 4. Looking forward to see it happen. I hope they go off smooth with both launches.
Starlink launch L18 has been scheduled for Feb 4 a while already. Now they are planned to launch on the same day, a first for SpaceX. The Airforce, now Spaceforce range has stated they are able to support parallel launches before. But only with launch vehicles that support automated flight abort capabilities. That's only SpaceX Falcon 9 so far. The new launch vehicles Vulcan by ULA and New Glenn by Blue Origin will support it too, when they fly.
https://twitter.com/SpaceX/status/1356807508975845381
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Now targeting two Falcon 9 launches of Starlink satellites on Thursday, February 4, pending range acceptance and recovery weather conditions. First Falcon 9 launch at 1:19 a.m. EST from SLC-40, followed by another Falcon 9 launch ~4 hours later at 5:36 a.m. EST from LC-39A
Tianwen 1 makes orbital correction as Mars arrival draws near
By Zhao Lei | chinadaily.com.cn | Updated: 2021-02-05 22:21
"China's Tianwen 1 Mars probe conducted its fourth orbital correction on Friday evening, as the spacecraft makes ready for its arrival in orbit around Feb 10, according to the China National Space Administration.
The robotic vehicle ignited one of its engines at 8 pm to make an orbital correction and ensure it would be flying in the right direction toward the Martian gravitational field, the administration said in a brief statement.
Tianwen 1 has flown for 197 days and more than 465 million kilometers on its journey to the planet. It is now around 184 million km from Earth and 1.1 million km from Mars. Depending on the two planets' orbits, Mars is between 55 and 400 million km from Earth.
The administration also published a black-and-white picture of Mars taken by Tianwen 1 when the probe was about 2.2 million kilometers from the red planet, the first snapshot from the Chinese craft.
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Tianwen 1, the country's first independent Mars mission, was launched by a Long March 5 heavy-lift carrier rocket on July 23 from the Wenchang Space Launch Center in Hainan province, kicking off the nation's planetary exploration program.
It will conduct a "braking" operation to decelerate and make sure it will be captured by Martian gravity around Feb 10, said China Aerospace Science and Technology Corp, the nation's leading space contractor.
The space administration previously said if everything goes according to schedule, the 5 metric ton probe, which consists of two major parts - the orbiter and the landing capsule - will travel more than 470 million km before entering Martian orbit, when it will be 193 million km from Earth.
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The spacecraft has already made four midcourse corrections and a deep-space orbital maneuver.
The mission's ultimate goal is to soft-land a rover in May on the southern part of Mars' Utopia Planitia - a large plain within Utopia, the largest recognized impact basin in the solar system - to conduct scientific surveys."
Tianwen 1 makes orbital correction as Mars arrival draws near - Chinadaily.com.cn
Where are the other spaceships? Already there or close behind?
Are earth and Mars on the same plane around the Sun? Presumably they will all want to orbit Mars around the "equator".
If so what determines their actual orbit, the first arrival takes its pick and the others have to keep a reasonable distance away from it?
Without looking the other probes up, they all arrive within a short time of each other. I don't think the probes need to consider each other, unless they want to cooperate in orbit. Mars is still big. Its surface is about the same as the dry land surface on Earth. There is plenty of space.
All planets orbit the sun in a similar inclination, called the ecliptic. There are differences, but not much. The chinese probe will land in the southern part of Utopia Planitia. So roughly at 40° from the equator. They will want their orbiter in the same or larger inclination to the equator, so it passes over the lander for communication. Inclination allows flying over much of the surface. Equatorial would limit the amount of surface accessible to observation. Probably the orbital inclination will be similar to the lander.
Utopia Planitia is a lowland, giving more atmosphere for braking and parachutes to slow down before landing. Most probes go into lowlands for that reason. Utopia Planitia is one of the locations on Mars that SpaceX is also considering for their landing site. Not too far from the equator for solar power, far enough so there is underground water ice. Wikipedia says, enough water to fill Lake Superior, so really a lot, 12.100 km³ for Lake Superior, 14.300km³ at Utopia Planitia.
Utopia Planitia - Wikipedia
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BTW, if that rover lands in an aera with underground ice we may get very interesting results. Orbital radar sats have detected a lot of water but the resolution is low and especially that radar can not detect well, how deep it is. The radar data can not detect the thickness of the regolith cover, which indicates it is no more than 10m to the ice below. But we do not know if it is 1m or 10m. Getting at strong hard ice 10m below may be hard. The chinese rover has ground penetrating radar similar to what the chinese Yutu Moon rover has. They will be able to measure the regolith cover thickness with good precision, probably too if it is massive ice, hard as concrete, or if it is broken, easy to mine. Info important to have if SpaceX decides to land there.
NASA is considering a new orbiter with much higher resolution radar that can map the whole of Mars for these data. But even if they decide to send it, it will be too late for SpaceX to help deciding their landing location. They are not going to wait 10 years for the data.
The UAE is on the cusp of a spatial breakthrough with less than two days to go for the Mars Orbit Insertion (MOI), which is scheduled to take place on Tuesday (February 9) at around 7:42pm.
The mission seeks to boost the UAE industry and science sectors' capacity and will also provide the much-needed data on the Martian atmosphere.
Most of the spacecraft have been in polar orbits that only offered views of the surface at fixed times of a day.
But the UAE's Hope spacecraft will be inserted into an inclined orbit that'll provide a comprehensive view.
Hessa Rashid Al Matroushi, Deputy Project Manager, Science, said: "The UAE had categorically set the objective at the outset. The mission has to espouse novel scientific causes. It has to be a continuation of the existing research on the Martian atmosphere and also compliment the critical gaps that currently exist."
She added: "The mission was designed by scientific objectives that are unique. We want to share the data with everyone. The UAE's objective is to share the data and advance the knowledge of the human race as far as the Martian atmosphere and space science is concerned.
The data will fill in the gaps in computer models of the Martian atmosphere.
These global climate models (GCMs) rely on basic physical laws to make predictions about the weather and climate.
Scientific objectives of the mission
Al Matroushi spelt out the three scientific objectives of the mission.
"The first one is about characterising the lower atmosphere of Mars. The second one is about relating the conditions of the lower atmosphere of Mars to those in the upper atmosphere and specifically looking into the escape of hydrogen and oxygen. The third one is looking at the changes of hydrogen and oxygen on the Red Planet," she said.
The researchers will take the data from the mission and then merge them together to create a snapshot of the Martian atmosphere in a bid to analyse how they change on a daily basis and in a sub-seasonal manner.
The data will be holistically compared with other existing global circulation models of the Martian atmosphere.
"We'll take the data sets that are currently available on Mars to carry out a comprehensive comparison. Another set of analysis includes taking the data from the lower atmosphere of Mars and linking it to the upper atmosphere. This will help gain in-depth information about the relationship between the different layers of the Martian atmosphere," said Al Matroushi.
A web portal has also been developed to access the data that the mission generates.
This portal will be up and running not only during the mission's lifetime but even beyond its existence.
Data visualisation tools
Omran Ahmed Al Hammadi, the lead at Science Data Centre, said: "Once the spacecraft transits to the science orbit, then we'll start collecting Mars observation data using the instruments that are on board the Hope Probe. Once the data is collected, it will be sent to the Mission Operation Centre. Then, the raw data will be sent to the Science Data Centre."
He added: "The first data set will be released four months after entering the science orbit, which is likely to be around September-October. Later, after every three months, a new data set will be released to conduct scientific analysis and research."
The researchers are expected to develop the visualisation tools, which will be used to decode the scientific data delivered by the spacecraft's instruments.
Noora Saeed Al Mheiri, science data analyst, lower atmosphere, said the expertise has been developed to decode the data sets.
"The researchers have focused on developing their analytical skills while poring over the data sets of previous missions to Mars. This will help us better understand the upcoming new set of data that will be received from Mars," she added.
Hope Probe: UAE on cusp of scientific breakthrough (msn.com)
Quotes from Dubai in arabic. A source in english stating the UAE probe has successfully completet the orbit insertion burn and is now orbiting Mars.
https://twitter.com/ChrisG_NSF/statu...73737174728706
From a german space forum: 80% of the arab scientists involved in the project are women.Quote:
ORBIT!!! CONGRATULATIONS to the United Arab Emirates, becoming only the 2nd nation after India to succeed in getting a probe to #Mars on its 1st attempt. The mission, an inspiration to many, is a critical step in sending humans to the Red Planet.
The chinese probe is expected to arrive at Mars tomorrow.
There's an interactive page here:
UAE's Hope probe to Mars an orbit away from glory | Mars - Hope Probe | Khaleej Times
They have a special stamp for your passport if you arrive in the UAE:
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What was interactive about it?
China's Tianwen-1 enters orbit around Mars - SpaceNews
Attachment 64538Quote:
China’s first interplanetary mission, Tianwen-1, successfully entered Mars orbit Feb. 10 following a 202-day journey through deep space.
Tianwen-1 initiated a near 15-minute burn of its 3000N main engine at 6:52 a.m. Eastern allowing the five-ton spacecraft to slow down and be gravitationally captured by Mars.
The Mars orbit insertion maneuver was designed to place the Tianwen-1 into an elliptical orbit of 400 by 180,000 kilometers inclined by 10 degrees, with an orbital period of 10 days.
With Mars more than 192 million kilometers away from Earth and a light time delay of 10 minutes and 40 seconds, the braking burn was by necessity pre-programmed. Intervention would not be possible in the event of an issue.
Tianwen-1 will gradually lower its orbit to allow for observations of Mars. It will also begin preparations for the entry, descent and landing attempt of a 240-kilogram solar powered rover, an event expected to take place around May or June, according to the China Aerospace Science and Technology Corp.
The orbiter is expected to approach as close as 265 kilometers to the surface, allowing a high-resolution camera to return images with a resolution of better than 0.50 meters per pixel.
This capability will be used to map a targeted rover landing site in Utopia Planitia. Landing coordinates of 110.318 degrees east longitude and 24.748 degrees north latitude had previously appeared in an official Chinese space publication before being removed.
Tianwen-1 joins the United Arab Emirates’ Hope mission, which arrived Tuesday, in orbit around the Red Planet. NASA’s Perseverance rover will arrive and make a soft landing attempt Feb. 18.
Soviet, Japanese and U.S. spacecraft have previously failed at the orbital insertion stage of the mission. The Soviet Mars 4 mission was unable to fire its engines and thus continued past Mars, while NASA’s Mars Climate Orbiter in 1999 approached too close, resulting in a mission-ending interaction with the Martian atmosphere.
Water-ice study among science objectives
Tianwen-1 is designed to collect an array of diverse data, both from orbit and on the Martian surface.
Long Xiao, a planetary scientist at the China University of Geosciences, told SpaceNews that Tianwen-1 equipped with a total 13 scientific payloads in to study Martian morphology and topography, study surface regolith and search for water ice with radars, study the composition of surface materials and the characteristics of the ionosphere, climate, environment and magnetic field.
“The most unique aim is to search and map the distribution of water ice on the surface and subsurface,” says Long. Two sounding radars will operate independently, with one onboard the orbiter. It will conduct a global survey but focus more on polar high latitude regions. The other is on the rover. “As radar data processing and interpretation is very complex, so the ground and satellite radar data together could provide more reliable results than a single one,” says Long.
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Zhang Xiaoping, an associate professor at Macau University of Science and Technology, likewise highlighted the potential of the radar payloads.
“We want to use the radar system to measure the subsurface structure of the Martian surface, especially for the buried water ice. This would allow us to study not only the underlying geologic structures of Mars, but also the potential source of water ice that supplies long-term human stay,” Zhang told SpaceNews.
“It is also important to measure the thickness and layers of ice and carbon dioxide in the polar region, to understand the seasonal atmosphere evolutions of Mars. By combining orbital and ground penetrating radar results, we will have a better understanding of the soil structure and evolution in the landing site.”
Deep space journey
Tianwen-1 launched from Wenchang, south China, July 23, 2020 on a Long March 5 heavy-lift rocket. The new launcher had crucially returned to flight in December 2019, having been grounded for more than 900 days following a 2017 failure.
The spacecraft carried out four trajectory correction maneuvers to refine its orbit and a larger deep space maneuver to alter its orbital inclination.
The European Space Agency provided China with support for the Launch and Early Orbit phase (LEOP) and later during Earth-Mars transfer with very precise tracking via Delta-DOR (delta Differential One way Range) measurements campaigns. This was carried out with ESA deep space 35-meter-diameter antennas located in Cebreros, Spain and New Norcia, Western Australia.
The Tianwen-1 orbiter has a design lifetime of one Martian year, or 687 Earth days. The rover, due to be named through a public vote and subsequent committee decision, has a design lifetime of around 90 Earth days.
The mission draws on technologies and capabilities developed through the Chang’e lunar program orbiters, lander and rovers, as well as head shielding and parachute expertise from Shenzhou human spaceflight endeavors
China is also developing a Mars sample return mission for around 2028-30.
As well as a shitload they probably stole from hacking into NASA's systems. :)Quote:
Originally Posted by Takeovers
A video of Tianwen-1 during orbit insertion, with Mars in the background. Not very good picture as the camera is designed to just show deployment of the solar panels.
Tianwen-1?s view of Mars during orbit insertion - YouTube
Fancy coming in behind the Arabs, how embarrassing.
:)
The planet is not red?
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Originally Posted by TheRealKW
It is. But the camera is not designed for showing it correct. It is over bright, just right to show the solar panels.
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Originally Posted by TheRealKW
Studio lighting.
:)
NASA perseverance rover approaches Mars.
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The trajectory (viewed "top down") of NASA's Perseverance rover, one week away from Mars arrival.
Cyan dots are spaced in one day intervals, shown at 00:00 UTC every day. Mars landing is planned at 20:55 UTC on Thursday 18 February.
NASA Mars rover reaches Mars as the third after UAE and China.
https://teakdoor.com/attachments/the...ctory_nasa-png
On Feb. 18, NASA's newest Mars rover, Perseverance, will descend into the Red Planet's atmosphere, braving temperatures equivalent to those on the surface of the sun as it deploys a supersonic parachute in hopes of a safe landing.
Earthbound viewers can follow the nail-biting action at home here on Live Science, on NASA Television or on the NASA website, which will carry live coverage from the Jet Propulsion Laboratory in California. The broadcast begins Feb. 18 at 2:15 p.m. EST (11:15 a.m. local time). There are also news conferences and informational sessions before landing day; a schedule is available on the Perseverance mission website.
Here's how to watch NASA's Perseverance rover land on Mars
The enigma of Enceladus
This tiny saturnian moon may be, pound for pound, the most valuable piece of real estate in the solar system.
By Morgan L. Cable, Linda Spilker (Astronomy)
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Researchers created this enhanced view of Enceladus’ south polar region by combining Cassini images taken through infrared, green, and ultraviolet filters. The tiger stripe fractures, the source of the plumes venting gas and dust into space, are prominently visible at center.
NASA/JPL-Caltech/SSI/Lunar and Planetary Institute/Paul Schenk (LPI, Houston)
“In the old time Pallas [Athena] heaved on high Sicily, and on huge Enceladus dashed down the isle, which burns with the burning yet of that immortal giant, as he breathes fire underground.”— Quintus Smyrnaeus, The Fall of Troy
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Enceladus, named after one of the Giants in Greek mythology, has an icy surface that reflects 81 percent of the light falling on it.
Cassini Imaging Team/JPL/ESA/NASA
Saturn’s sixth-largest moon, Enceladus has a diameter of only 310 miles (500 kilometers), and a mass less than 1/50,000 that of Earth. When it comes to places to look for life, however, Enceladus is at the top of the list, and it’s right in our cosmic backyard.
A bit ignored at firstEnglish astronomer William Herschel discovered Enceladus in 1789, but it remained an enigma until the Cassini mission began orbiting Saturn in 2004. Prior to Cassini, Enceladus was a bit ignored. We didn’t know liquid water could exist that far out in the solar system, so why would anyone be that interested in another boring, dead ball of ice?
That all changed one year later, when Cassini’s magnetometer (think: fancy compass) detected something strange in Saturn’s magnetic field near Enceladus. This suggested the moon was active. Subsequent passes by Enceladus revealed four massive fissures — dubbed “tiger stripes” — in a hot spot centered on the south pole. And emanating from those cracks was a massive plume of water vapor and ice grains. Enceladus lost its label of being a dead relic of a bygone era and leaped to center stage as a dynamic world with a subsurface ocean.
But was it really an underground ocean, or more of a local southern sea? Thankfully, Cassini could answer this question, too. By verifying excess wobble over Enceladus’ orbital period, the imaging cameras confirmed that the icy crust is not connected to the world’s rocky core. This could only be possible if the crust is floating on a global, subsurface, liquid-water ocean.
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Plumes spray water ice and vapor from many locations along the so-called “tiger stripes” crossing Enceladus’ south polar terrain. The four prominent fractures are about 84 miles (135 kilometers) long. This two-image mosaic of the moon shows the curvilinear arrangement of geysers, erupting from the fractures.
NASA/JPL/Space Science Institute
And Cassini didn’t stop there. Mass spectrometers aboard the spacecraft analyzed the gas and grains during multiple flythroughs of the plume. These instruments, the Ion and Neutral Mass Spectrometer (INMS) and Cosmic Dust Analyzer (CDA), found the plume contains mostly water, but also salts, ammonia, carbon dioxide, and small and large organic molecules. These findings help us paint a picture of the world underneath the ice: a possibly habitable ocean that’s slightly alkaline, with access to chemical energy in the water and geothermal energy at the rocky seafloor.
Possible energy sources
One of the greatest legacies of the Cassini mission is that it established Enceladus as possessing all three ingredients for life as we know it: water, chemistry, and energy. Water in the ocean — check. Chemistry in the simple and complex organics detected in the plume — check. These could be utilized to form the molecular machinery of life.
Energy takes a bit more explaining.
It is likely that hydrothermal vents are present at the seafloor of Enceladus. We know this because of three lines of evidence. First, INMS detected methane in the plume, at higher concentrations than would exist if sourced from clathrates (water-ice cages at high pressure with methane trapped inside) or other reservoirs in the ice. Methane is a key product of hydrothermal systems.
Second, CDA discovered silica nanograins of a particular size and oxidation state traced to the ocean. These only could have formed where liquid water is touching rock at temperatures of at least 194 degrees Fahrenheit (90 degrees Celsius), in the range of hydrothermal vents like “white smokers” here on Earth.
And third, the recent confirmation of molecular hydrogen in the plume by the INMS team strongly suggests interaction of liquid water with a rocky core.
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And third, the recent confirmation of molecular hydrogen in the plume by the INMS team strongly suggests interaction of liquid water with a rocky core.On Earth, hydrothermal vents at the base of the Mid-Atlantic Ridge host teeming ecosystems, living as far removed as one can imagine from photosynthesis. These habitats survive off of geothermal and chemical energy. A similar community might exist near a hydrothermal vent at the seafloor of Enceladus.
So, we have water, chemistry, and energy. Let’s say they have mixed together long enough for life to form. (Your guess is as good as anybody’s here — estimates range from 100,000 to 25 million years.) How might we detect it?
Assuming an energy-limited scenario (a good analog is Lake Vostok, a body of water in Antarctica that’s been covered with ice for the last 35 million years), we are probably looking at cell densities in the range of 100–1,000 cells per milliliter of ocean water. For reference, Earth’s oceans have about 1 million cells or more per milliliter.
We assume this life would use readily available building blocks — such as amino acids, which are abundant in carbonaceous chondrites and likely present all over the saturnian system — in numbers on par with Earth-based life.
This assumption is reasonable because life needs chemical complexity to carry out the reactions that keep cells functional. Then we are looking at concentrations of biomarkers on the order of less than 1 part per billion. That’s tough for current instruments to achieve, without some kind of concentration step.
Does this mean we have to wait for more advanced instruments before we search for life? Nope.
Organic enrichment in the plumeOf all the ice grains detected by the CDA instrument, a fraction had a high concentration of organic molecules, something the CDA team calls high mass organic cations (HMOC). While the instrument couldn’t specifically identify the structures of the HMOCs, a thorough analysis led to some educated guesses, such as aromatics (carbon-containing ringed structures) and oxygen- and nitrogen-bearing species. Within Enceladus’ ocean, there may be a complex organic soup of molecules.
The best theory for how these organic-rich ice grains might form is due to something called “bubbles bursting.” The grains were not only organic-rich, but also salt-poor, suggesting they came from an organic layer at the ice-ocean interface.
On Earth we have something similar floating at the surface of our ocean. It’s a film called an “organic microlayer,” as it’s not very thick and is typically made up of organics from biological activity (i.e., bits of cells) and from other sources, too.
The organic molecules like to hang out together and aren’t huge fans of salts or water, so they push these things out of the microlayer. Then, wave activity causes bubbles in this microlayer to burst, generating aerosols that are organic-rich and salt-poor.
A similar process may be happening on Enceladus. Organic molecules in the ocean may be concentrated at the ocean-ice boundary, and, just like on Earth, may force out the water and salts from this film. As the liquid surface at the base of the plume boils into vacuum, bubbles might burst and disperse the organic film, producing some grains that have a lot of organics inside, and little salt.
The result of all of this? Enceladus may be helping to concentrate the very things astrobiologists want to study the most: organic molecules.
Aerosols on Earth boast organic molecules enriched hundreds to thousands of times over typical ocean concentrations. If we collect samples by flying through the plume or by landing on the surface, we may have a greater chance of detecting evidence of life on Enceladus, if it exists.
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Cassini was a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. The spacecraft spent more than 13 years studying Saturn, its rings, and its moons. It captured some 450,000 images and returned 635 gigabytes of science data.
NASA/JPL-Caltech
Future mission conceptsEnceladus has captivated us and given us more than enough reasons to go back. Many possible missions would do the job, and a few have been proposed in the post-Cassini era, although not yet selected by NASA to proceed.
Some would do as Cassini did — fly through the plume and analyze the gas and grains — but with upgraded instruments capable of much more sensitive and effective tests for life. Others would land on Enceladus’ south polar terrain, sampling fresh snow deposited onto the surface from the plume.
Even more ambitious concepts include a sample return mission (although with a round-trip time of 14 years, we would have to wait awhile to get that sample) or various climbing or melting robots to descend the 1.2 to 6.2 miles (2 to 10 km) through the ice shell and reach the ocean itself.
Whatever we send, the next mission to Enceladus — if indeed astrobiology is its main objective — will need a well-designed suite of instruments capable of searching for multiple, independent lines of evidence for life. Our understanding of life’s characteristics has advanced greatly since the Viking era, the last time NASA openly stated the search for life as the primary goal.
Back when the two Viking landers touched down on Mars in 1976, for example, we knew only two of the three branches of life. (Archaea, the third and most primitive branch of the tree of life, was discovered in 1977.) The Viking landers had three biological experiments designed to search for life in the martian regolith. One test result was positive, one was negative, and one was ambiguous. Since then, we have learned a great deal about how to design experiments such that an ambiguous result is much less likely.
We are also getting better at searching for biosignatures that are as agnostic to Earth life as possible. For example, a future mission to Enceladus might not target DNA, which is Earth-life-specific, but it might look for a molecule that could serve the same function for alien life: a large molecule with repeating subunits (akin to an alphabet) capable of storing information, such as the blueprints to build an alien cell. If such a molecule is detected, along with positive identification of multiple other biosignatures, a strong case could be made for the first detection in human history of life on another world.
Active, accessible, and relevant
Enceladus is not the only place that could host life. Europa has an even larger liquid water reservoir, and Titan’s ocean may entertain an unimaginably rich organic chemistry.
But Enceladus is the one place where researchers know for certain that they can access material from the ocean without the need to dig or drill (or even land). We can use technology available right now to test the hypothesis of whether life may be present somewhere else in the solar system.
Enceladus may be a tiny moon, but good things often come in small packages. The time is now to answer the key question that has driven us since we first looked up: Are we alone?
link that includes the pictures here
Perseverance should land in about 7 hours 27 minutes from now. Live stream starts in 5 hours.
Watch NASA’s Perseverance Rover Land on Mars! - YouTube
More info Mars 2020 Perseverance Rover - NASA Mars