Orbit diagram for asteroid 2016 RB1's close approach to Earth on September 7, 2016. Credit: NASA/JPL Small Body Database.
As NASA prepares to send a spacecraft to a distant asteroid, another space rock made a surprise visit to Earth’s vicinity. The newly discovered small asteroid, named 2016 RB1, passed safely by Earth, coming within approximately 23,900 miles (38,463 km) of our planet, or just outside the orbit of many communications satellites.
The asteroid passed by Earth at 1:28 p.m. Eastern Time (1728 UT).
An animation of asteroid 2016 RB1 from images obtained by the Virtual Telescope Project on September 6, 2016. Credit: Gianluca Masi/Virtual Telescope Project.
Click on the image if it is not animating in your browser.
The asteroid was discovered on Monday, September 5 by the Mt. Lemmon Survey telescope in Tucson, Arizona. 2016 RB1 is estimated to be between 24 to 52 feet (7.3 – 16 meters) across, which is just a bit smaller than the Chelyabinsk meteor that exploded over northern Russian in February 2013, which was estimated to be around 56 ft (17 meters) wide.
On Thursday, September 8, NASA hopes to launch its OSIRIS-ReX mission to study asteroid Bennu and conduct a sample return, with the sample coming back to Earth by 2023. With the mission, scientists hope to learn more about the formation and evolution asteroids and of the Solar System as a whole.
Here’s a graphic comparing the small asteroid 2016 RB1 to other objects, compiled by Mikko Tuomela and Massimo Orgiazzi.
Objects on Earth and in space compared to the newly found asteroid 2016 RB1 (center of graphic). Compiled by Mikko Tuomela and Massimo Orgiazzi. Used by permission.
An image of 2016 RB1 taken on September 7, 2016, remotely from the Q62 iTelescope network (Siding Spring, Australia). Credit: Ernesto Guido.
2016 RB1 is the third asteroid so far in September 2016 that traveled between the Earth and the Moon. Asteroid 2016 RR1 passed by at 0.32 lunar distances on September 2, and just a few hours later, asteroid 2016 RS1 passed by at 0.48 times the Earth-moon distance. But this latest asteroid pass is the closest, at 0.10 lunar distances.
From its orbit, astronomers have determined 2016 RB1 is likely an Aten asteroid, a group of Near-Earth Objects that cross the orbits of Earth, Venus and even Mercury.
NASA’s OSIRIS-REx asteroid sampling spacecraft is rolled out to pad 41 for launch atop a United Launch Alliance Atlas V rocket on Sept. 8, 2016 from Space Launch Complex 41 on Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com
NASA’s OSIRIS-REx asteroid sampling spacecraft is rolled out to pad 40 for launch atop a United Launch Alliance Atlas V rocket on Sept. 8, 2016 from Space Launch Complex 41 on Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com
KENNEDY SPACE CENTER, FL – OSIRIS-Rex, NASA’s first mission to retrieve and return samples of “pristine materials” from the surface of an asteroid and return them to Earth for high powered analysis by the world’s most advanced science instruments is encapsulated in the nose cone that’s bolted atop its Atlas rocket that has just been rolled out to its Earth departure launch pad.
It’s a groundbreaking mission that could inform us about astrobiology and yield significant clues to help determine the ‘Origin of Life’ on Earth.
NASA’s Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer (OSIRIS-REx) spacecraft will launch from Space Launch Complex 41 at Cape Canaveral Air Force Station on a United Launch Alliance Atlas V rocket on September 8 at 7:05 p.m. EDT.
The United Launch Alliance Atlas V rocket and OSIRIS-REx spacecraft were moved about 1800 feet from the Vertical Integration Facility (VIF) – where the rocket is assembled- to launch pad 41 starting at about 9 a.m. this morning September 7, 2018.
Watch this Atlas V rocket roll video:
The ULA, NASA and science team conducted a launch readiness review yesterday and gave the GO for launch with all systems passing the stringent rocket and safety review. The even search for signs of any debris from last week’s SpaceX Falcon 9 explosion at the adjacent pad 40 located about a mile south. No signs of any debris or damage were found at pad 40 or the rocket and spacecraft.
NASA’s OSIRIS-REx asteroid sampling spacecraft is rolled out to pad 40 for launch atop a United Launch Alliance Atlas V rocket on Sept. 8, 2016 from Space Launch Complex 41 on Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com
The weather forecast is currently 80% GO for favorable conditions. The only concern is for cumulus clouds.
There are 3 opportunities in a row to launch OSIRIS-Rex.
In case of a delay 24 or 48 hour delay, the forecast drops only slightly to 70% GO.
NASA’s OSIRIS-REx asteroid sampling spacecraft, return capsule and payload fairings inside the Payloads Hazardous Servicing Facility high bay at NASA’s Kennedy Space Center is being processed for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
OSIRIS-REx goal is to fly on a roundtrip seven-year journey of some 4.5 billion miles to the near-Earth asteroid target named Bennu and back.
Watch this mission video:
Video Caption: This video describes the seven-year journey of NASA’s OSIRIS-Rex mission from launch and cruising through space to asteroid Bennu and back. The probe will study Bennu, grab a 2 ounce or more sample from the surface and bring it back to Earth for lab study by researchers. Credit: Lockheed Martin/NASA
101955 Bennu is a near Earth asteroid discovered in 1999. It was selected specifically because it is a carbon-rich asteroid.
While orbiting Bennu starting in 2018 it will move in close and snatch pristine soil samples containing organic materials from the surface using the TAGSAM collection dish, and bring them back to Earth for study by researchers using all of the most sophisticated science instruments available to humankind.
The asteroid is 1,614-foot (500 m) in diameter and crosses Earth’s orbit around the sun every six years.
“The primary objective of the OSIRIS-Rex mission is to bring back pristine material from the surface of the carbonaceous asteroid Bennu, OSIRIS-Rex Principal Investigator Dante Lauretta told Universe Today in the PHSF, as the probe was undergoing final preparation for shipment to the launch pad.
“It records the very first material that formed from the earliest stages of solar system formation. And we are really interested in the evolution of carbon during that phase. Particularly the key prebiotic molecules like amino acids, nucleic acids, phosphates and sugars that build up. These are basically the biomolecules for all of life.”
Artist’s conception of NASA’s OSIRIS-REx sample return spacecraft collecting regolith samples at asteroid Bennu. Credits: NASA/Lockheed Martin
OSIRIS-REx will gather rocks and soil and bring at least a 60-gram (2.1-ounce) sample back to Earth in 2023. It has the capacity to scoop up to about 1 kg or more.
The mission will help scientists investigate how planets formed and how life began. It will also improve our understanding of asteroids that could impact Earth by measuring the Yarkovsky effect.
I asked Lauretta to explain in more detail why was Bennu selected as the target to answer fundamental questions related to the origin of life ?
“We selected asteroid Bennu as the target for this mission because we feel it has the best chance of containing those pristine organic compounds from the early stage of solar system formation,” Lauretta told me.
And that information is based on our ground based spectral characterization using telescopes here on Earth. Also, space based assets like the Hubble Space Telescope and the Spitzer Space Telescope.
What is known about the presence of nitrogen containing compounds like amino acids and other elements on Bennu that are the building blocks of life?
“When we look at the compounds that make up these organic materials in these primitive asteroidal materials, we see a lot of carbon,” Lauretta explained.
“But we also see nitrogen, oxygen, hydrogen, sulfur and phosphorous. We call those the CHONPS. Those are the six elements we really focus on when we look at astrobiology and prebiotic chemistry and how those got into the origin of life.”
The OSIRIS-REx spacecraft was built for NASA by prime contractor Lockheed Martin at their facility near Denver, Colorado and flown to the Kennedy Space Center on May 20.
It will map the chemistry and mineralogy of the primitive carbonaceous asteroid. The team will initially select about 10 target areas for further scrutiny as the sampling target. This will be whittled down to two, a primary and backup, Enos told me.
After analyzing the data returned, the science team then will select a site where the spacecraft’s robotic sampling arm will grab a sample of regolith and rocks. The regolith may record the earliest history of our solar system.
Engineers will command the spacecraft to gradually move on closer to the chosen sample site, and then extend the arm to snatch the pristine samples with the TAGSAM sample return arm.
PI Lauretta will make the final decision on when and which site to grab the sample from.
“As the Principal Investigator for the mission I have responsibility for all of the key decisions during our operations,” Lauretta replied. “So we will be deciding on where we want to target our high resolution investigations for sample site evaluation. And ultimately what is the one location we want to send the spacecraft down to the surface of the asteroid to and collect that sample.”
“And then we have to decide like if we collected enough sample and are we ready to stow it in the sample return capsule. Or are we going to use one of our 2 contingency bottles of gas to go for a second attempt.”
“The primary objective is one successful sampling event. So when we collect 60 grams or 2 ounces of sample then we are done!”
“In the event that we decide to collect more, it will be intermixed with anything we collected on the first attempt.”
The priceless sample will then be stowed in the on board sample return capsule for the long journey back to Earth.
Bennu is an unchanged remnant from the collapse of the solar nebula and birth of our solar system some 4.5 billion years ago, little altered over time.
After a 7 year journey to asteroid Bennu and back, NASA’s OSIRIS-Rex sample return capsule will land by parachute in the Utah desert on Sept. 24, 2023. Credits: NASA/Lockheed Martin
Bennu is a near-Earth asteroid and was selected for the sample return mission because it could hold clues to the origin of the solar system and host organic molecules that may have seeded life on Earth.
OSIRIS-REx will return the largest sample from space since the American and Soviet Union’s moon landing missions of the 1970s.
OSIRIS-REx is the third mission in NASA’s New Frontiers Program, following New Horizons to Pluto and Juno to Jupiter, which also launched on Atlas V rockets.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is responsible for overall mission management.
The OSIRIS-REx spacecraft, enclosed in a payload fairing, is lifted Aug. 29, 2016 at Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida. The United Launch Alliance Atlas V rocket that is to lift OSIRIS-REx into space was stacked at SLC-41 so the spacecraft and fairing could be hoisted up and bolted to the rocket. Photo credit: NASA/Dimitri Gerondidakis
OSIRIS-REx complements NASA’s Asteroid Initiative – including the Asteroid Redirect Mission (ARM) which is a robotic spacecraft mission aimed at capturing a surface boulder from a different near-Earth asteroid and moving it into a stable lunar orbit for eventual up close sample collection by astronauts launched in NASA’s new Orion spacecraft. Orion will launch atop NASA’s new SLS heavy lift booster concurrently under development.
Watch for Ken’s continuing OSIRIS-REx mission and launch reporting from on site at the Kennedy Space Center and Cape Canaveral Ait Force Station, FL.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Learn more about OSIRIS-REx, InSight Mars lander, SpaceX missions, Juno at Jupiter, SpaceX CRS-9 rocket launch, ISS, ULA Atlas and Delta rockets, Orbital ATK Cygnus, Boeing, Space Taxis, Mars rovers, Orion, SLS, Antares, NASA missions and more at Ken’s upcoming outreach events:
Sep 7-9: “OSIRIS-REx lainch, SpaceX missions/launches to ISS on CRS-9, Juno at Jupiter, ULA Delta 4 Heavy spy satellite, SLS, Orion, Commercial crew, Curiosity explores Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings
Dr Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona, Tucson, and Dr. Ken Kremer, Universe Today point to NASA’s OSIRIS-REx asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility at the Kennedy Space Center on Aug. 20, 2016. Credit: Ken Kremer/kenkremer.com
Freddie Mercury on stage in 1977. Image: By FreddieMercurySinging21978.jpg: Carl Lender derivative work: Lošmi - FreddieMercurySinging21978.jpg, CC BY-SA 3.0
Freddie Mercury, the frontman from the rock band Queen, is getting his name etched in the night sky. No, they’re not naming another planet after him. That would be confusing. Instead, an asteroid will bear the name of the iconic singer.
If you don’t know much about the band Queen, there’s a connection between them and astronomy. Brian May, the band’s guitarist, holds a PhD. in astrophysics. He studied reflected light from interplanetary dust and the velocity of dust in the plane of the Solar System. But when Queen became mega-popular in the 70’s, he abandoned astrophysics, for the most part.
Brian May is still involved with space, and has an interest in asteroids. He helped the ESA launch Asteroid Day in June 2016, to raise awareness of the threat that asteroids pose to Earth. So there’s the connection.
As for the asteroid that will bear Freddie Mercury’s name, it was previously named Asteroid 17473, but will now be known as Asteroid FreddieMercury 17473. It’s a rock about 3.5 km in diameter in the asteroid belt between Mars and Jupiter.
Today would have been Freddie’s 70th birthday, if he were still alive. So this naming is a fitting commemorative gesture. According to the International Astronomical Union, who handles the naming of objects in space, the naming of the asteroid is in honour of “Freddie’s outstanding influence in the world.”
Brian May explains things in this video:
We’re mostly science-minded people, so you may be skeptical of Freddie’s influence in the world. He was no scientist, that’s for sure. But if you lived through Queen’s heyday, as I did, you can sort of see it.
Freddie Mercury was a very polished entertainer, with a great voice and fantastic stage presence. He mastered the theatrical side of performing as a rock frontman, and his voice spanned four octaves. The music he made with his band-members in Queen was very original. Mercury was a creative force, that’s for sure.
Check out “Killer Queen” from 1974.
Plus, William Shatner (aka Captain James Tiberius Kirk) clearly had a warm spot in his heart for Freddie and the rest of Queen. How else to explain his version of Queen’s timeless tune “Bohemian Rhapsody?”
If that isn’t a ringing endorsement of Freddie Mercury and Queen, I don’t know what is.
The asteroid that will bear Freddie Mercury’s name was discovered by Belgian astronomer Henri Debehogne in 1991. It travels an elliptical path around the Sun, and never comes closer than 350 million km to Earth. It isn’t very reflective, so only powerful telescopes can see it. But there it’ll be, for anyone with a powerful enough telescope to look with, as long as human civilization lasts.
Freddie Mercury isn’t the first entertainer to have something in space bear his name. In fact, he’s not even the first member of Queen to have that honor. An asteroid first seen in 1998 now bears the name Asteroid 52665 Brianmay, in honor of the guitarist from Queen.
Other musicians and singers who’ve had space rocks named after them include the Beatles, Enya, Frank Zappa, David Bowie, Aretha Franklin, Yes, and Bruce Springsteen. Authors Kurt Vonnegut, Vladimir Nabokov, and Douglas Adams and the characters Don Quixote, James Bond, Sherlock Holmes and Dr Watson also have the honor.
As for the rock itself, Oxford astrophysics professor Chris Lintott told the Guardian, “I think it’s wonderful to name an asteroid after Freddie Mercury. Pleasingly, it’s on a slightly eccentric orbit about the sun, just as the man himself was.”
Freddie died in 1991 from complications from AIDS, but his music still lives on. Maybe Asteroid FreddieMercury 17473 will help us remember him.
NASA’s OSIRIS-REx asteroid sampling spacecraft, return capsule and payload fairings inside the Payloads Hazardous Servicing Facility high bay at NASA's Kennedy Space Center is being processed for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
NASA’s OSIRIS-REx asteroid sampling spacecraft, return capsule and payload fairings inside the Payloads Hazardous Servicing Facility high bay at NASA’s Kennedy Space Center is being processed for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
KENNEDY SPACE CENTER, FL – OSIRIS-Rex, the first American sponsored probe aimed at retrieving “pristine materials” from the surface of an asteroid and returning them to Earth has been fully assembled at its Florida launch base and is ready to blastoff ten days from today on Sep. 8. It’s a groundbreaking mission that could inform us about astrobiology and the ‘Origin of Life.’
“We are interested in that material because it is a time capsule from the earliest stages of solar system formation,” said Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona, Tucson, in an interview with Universe Today beside the completed spacecraft inside the Payloads Hazardous Servicing Facility, or PHSF, clean room processing facility at NASA’s Kennedy Space Center in Florida.
With virtually all prelaunch processing complete, leading members of the science, engineering and launch team including Lauretta met with several members of the media, including Universe Today, inside the clean room for a last and exclusive up-close look and briefing with the one-of-its-kind $800 million Asteroid sampling probe last week.
OSIRIS-REx goal is to fly on a roundtrip seven-year journey to the near-Earth asteroid target named Bennu and back. 101955 Bennu is a near Earth asteroid and was selected specifically because it is a carbon-rich asteroid.
While orbiting Bennu it will move in close and snatch pristine soil samples containing organic materials from the surface using the TAGSAM collection dish, and bring them back to Earth for study by researchers using all of the most sophisticated science instruments available to humankind.
“The primary objective of the OSIRIS-Rex mission is to bring back pristine material from the surface of the carbonaceous asteroid Bennu, OSIRIS-Rex Principal Investigator Dante Lauretta told Universe Today in the PHSF, as the probe was undergoing final preparation for shipment to the launch pad.
“It records the very first material that formed from the earliest stages of solar system formation. And we are really interested in the evolution of carbon during that phase. Particularly the key prebiotic molecules like amino acids, nucleic acids, phosphates and sugars that build up. These are basically the biomolecules for all of life.”
Overhead view of NASA’s OSIRIS-REx asteroid sampling spacecraft with small white colored sample return canister atop, inside the Payloads Hazardous Servicing Facility high bay at NASA’s Kennedy Space Center. Launch is slated for Sep. 8, 2016 to asteroid Bennu from Cape Canaveral Air Force Station, FL. Credit: Julian Leek
OSIRIS-REx will gather rocks and soil and bring at least a 60-gram (2.1-ounce) sample back to Earth in 2023. It has the capacity to scoop up to about 1 kg or more.
The mission will help scientists investigate how planets formed and how life began. It will also improve our understanding of asteroids that could impact Earth by measuring the Yarkovsky effect.
I asked Lauretta to explain in more detail why was Bennu selected as the target to answer fundamental questions related to the origin of life?
“We selected asteroid Bennu as the target for this mission because we feel it has the best chance of containing those pristine organic compounds from the early stage of solar system formation,” Lauretta told me.
“And that information is based on our ground based spectral characterization using telescopes here on Earth. Also, space based assets like the Hubble Space Telescope and the Spitzer Space Telescope.”
What is known about the presence of nitrogen containing compounds like amino acids and other elements on Bennu that are the building blocks of life?
“When we look at the compounds that make up these organic materials in these primitive asteroidal materials, we see a lot of carbon,” Lauretta explained.
“But we also see nitrogen, oxygen, hydrogen, sulfur and phosphorous. We call those the CHONPS. Those are the six elements we really focus on when we look at astrobiology and prebiotic chemistry and how those got into the origin of life.”
View of science instrument suite and TAGSAM robotic sample return arm on NASA’s OSIRIS-REx asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility at NASA’s Kennedy Space Center. Probe is slated for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com
The OSIRIS-REx spacecraft was built for NASA by prime contractor Lockheed Martin at their facility near Denver, Colorado and flown to the Kennedy Space Center on May 20.
For the past three months it has undergone final integration, processing and testing inside the PHSF under extremely strict contamination control protocols to prevent contamination by particle, aerosols and most importantly organic residues like amino acids that could confuse researchers seeking to discover those very materials in the regolith samples gathered for return to Earth.
The PHFS clean room was most recently used to process the Orbital ATK Cygnus space station resupply vehicles. It has also processed NASA interplanetary probes such as the Curiosity Mars Science Laboratory and MAVEN Mars orbiter missions.
Side view of NASA’s OSIRIS-REx asteroid sampling spacecraft showing the High Gain Antenna at left and solar panel, inside the Payloads Hazardous Servicing Facility high bay at NASA’s Kennedy Space Center. Probe is being processed for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com
The spacecraft will reach Bennu in 2018. Once within three miles (5 km) of the asteroid, the spacecraft will begin at least six months of comprehensive surface mapping of the carbonaceous asteroid, according to Heather Enos, deputy principal investigator, in an interview with Universe Today.
“We will then move the spacecraft to within about a half kilometer or so to collect further data,” Enos elaborated.
It will map the chemistry and mineralogy of the primitive carbonaceous asteroid. The team will initially select about 10 target areas for further scrutiny as the sampling target. This will be whittled down to two, a primary and backup, Enos told me.
After analyzing the data returned, the science team then will select a site where the spacecraft’s robotic sampling arm will grab a sample of regolith and rocks. The regolith may record the earliest history of our solar system.
Engineers will command the spacecraft to gradually move on closer to the chosen sample site, and then extend the arm to snatch the pristine samples the TAGSAM sample return arm.
PI Lauretta will make the final decision on when and which site to grab the sample from.
“As the Principal Investigator for the mission I have responsibility for all of the key decisions during our operations,” Lauretta replied. “So we will be deciding on where we want to target our high resolution investigations for sample site evaluation. And ultimately what is the one location we want to send the spacecraft down to the surface of the asteroid to and collect that sample.”
“And then we have to decide like if we collected enough sample and are we ready to stow it in the sample return capsule. Or are we going to use one of our 2 contingency bottles of gas to go for a second attempt.”
“The primary objective is one successful sampling event. So when we collect 60 grams or 2 ounces of sample then we are done!”
“In the event that we decide to collect more, it will be intermixed with anything we collected on the first attempt.”
The priceless sample will then be stowed in the on board sample return capsule for the long journey back to Earth.
NASA’s OSIRIS-Rex asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility high bay at NASA’s Kennedy Space Center. Launch is slated for Sep. 8, 2016 to asteroid Bennu from Cape Canaveral Air Force Station, FL. Credit: Lane Hermann
Bennu is an unchanged remnant from the collapse of the solar nebula and birth of our solar system some 4.5 billion years ago, little altered over time.
Bennu is a near-Earth asteroid and was selected for the sample return mission because it could hold clues to the origin of the solar system and host organic molecules that may have seeded life on Earth.
Artist’s conception of NASA’s OSIRIS-REx spacecraft at Bennu. Credits: NASA/GSFC
OSIRIS-REx will return the largest sample from space since the American and Soviet Union’s moon landing missions of the 1970s.
Watch this USLaunchReport video shot during media visit inside the PHSF on Aug. 20, 2016:
Video caption: Our first introduction to the OSIRIS-REx asteroid bound mission in search of the origins of life, from inside the Payloads Hazardous Servicing Facility at NASA’s Kennedy Space Center on Aug. 20, 2016. Credit: USLaunchReport
OSIRIS-REx is the third mission in NASA’s New Frontiers Program, following New Horizons to Pluto and Juno to Jupiter, which also launched on Atlas V rockets.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is responsible for overall mission management.
OSIRIS-REx complements NASA’s Asteroid Initiative – including the Asteroid Redirect Mission (ARM) which is a robotic spacecraft mission aimed at capturing a surface boulder from a different near-Earth asteroid and moving it into a stable lunar orbit for eventual up close sample collection by astronauts launched in NASA’s new Orion spacecraft. Orion will launch atop NASA’s new SLS heavy lift booster concurrently under development.
Watch for Ken’s continuing OSIRIS-REx mission and launch reporting from on site at the Kennedy Space Center and Cape Canaveral Ait Force Station, FL.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Dr Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona, Tucson, and Dr. Ken Kremer, Universe Today point to NASA’s OSIRIS-Rex asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility at the Kennedy Space Center on Aug. 20, 2016. Credit: Ken Kremer/kenkremer.comThe University of Arizona’s camera suite, OCAMS, sits on a test bench that mimics its arrangement on the OSIRIS-REx spacecraft. The three cameras that compose the instrument – MapCam (left), PolyCam and SamCam – are the eyes of NASA’s OSIRIS-REx mission. They will map the asteroid Bennu, help choose a sample site, and ensure that the sample is correctly stowed on the spacecraft. Credits: University of Arizona/Symeon Platts
Between the orbits of Mars and Jupiter lies the Solar System’s Main Asteroid Belt. Consisting of millions of objects that range in size from hundreds of kilometers in diameter (like Ceres and Vesta) to one kilometer or more, the Asteroid Belt has long been a source of fascination for astronomers. Initially, they wondered why the many objects that make it up did not come together to form a planet. But more recently, human beings have been eyeing the Asteroid Belt for other purposes.
Whereas most of our efforts are focused on research – in the hopes of shedding additional light on the history of the Solar System – others are looking to tap for its considerable wealth. With enough resources to last us indefinitely, there are many who want to begin mining it as soon as possible. Because of this, knowing exactly how long it would take for spaceships to get there and back is becoming a priority.
Distance from Earth:
The distance between the Asteroid Belt and Earth varies considerably depending on where we measure to. Based on its average distance from the Sun, the distance between Earth and the edge of the Belt that is closest to it can be said to be between 1.2 to 2.2 AUs, or 179.5 and 329 million km (111.5 and 204.43 million mi).
The asteroids of the inner Solar System and Jupiter: The donut-shaped asteroid belt is located between the orbits of Jupiter and Mars. Credit: Wikipedia Commons
However, at any given time, part of the Asteroid Belt will be on the opposite side of the Sun, relative to Earth. From this vantage point, the distance between Earth and the Asteroid Blt ranges from 3.2 and 4.2 AU – 478.7 to 628.3 million km (297.45 to 390.4 million mi). To put that in perspective, the distance between Earth and the Asteroid Belt ranges between being slightly more than the distance between the Earth and the Sun (1 AU), to being the same as the distance between Earth and Jupiter (4.2 AU) when they are at their closest.
But of course, for reasons of fuel economy and time, asteroid miners and exploration missions are not about to take the long way! As such, we can safely assume that the distance between Earth and the Asteroid Belt when they are at their closest is the only measurement worth considering.
Past Missions:
The Asteroid Belt is so thinly populated that several unmanned spacecraft have been able to move through it on their way to the outer Solar System. In more recent years, missions to study larger Asteroid Belt objects have also used this to their advantage, navigating between the smaller objects to rendezvous with bodies like Ceres and Vesta. In fact, due to the low density of materials within the Belt, the odds of a probe running into an asteroid are now estimated at less than one in a billion.
The first spacecraft to make a journey through the asteroid belt was the Pioneer 10 spacecraft, which entered the region on July 16th, 1972 (a journey of 135 days). As part of its mission to Jupiter, the craft successfully navigated through the Belt and conducted a flyby of Jupiter (in December of 1973) before becoming the first spacecraft to achieve escape velocity from the Solar System.
An artist’s illustration of NASA’s Dawn spacecraft approaching Ceres. Image: NASA/JPL-Caltech.
For the most part, these missions were part of missions to the outer Solar System, where opportunities to photograph and study asteroids were brief. Only the Dawn, NEAR and JAXA’s Hayabusamissions have studied asteroids for a protracted period in orbit and at the surface. Dawn explored Vesta from July 2011 to September 2012, and is currently orbiting Ceres (and sending back gravity data on the dwarf planet’s gravity) and is expected to remain there until 2017.
Fastest Mission to Date:
The fastest mission humanity has ever mounted was the New Horizons mission, which was launched from Earth on Jan. 19th, 2006. The mission began with a speedy launch aboard an Atlas V rocket, which accelerated it to a a speed of about 16.26 km per second (58,536 km/h; 36,373 mph). At this speed, the probe reached the Asteroid Belt by the following summer, and made a close approach to the tiny asteroid 132524 APL by June 13th, 2006 (145 days after launching).
However, even this pales in comparison to Voyager 1, which was launched on Sept. 5th, 1977 and reached the Asteroid Belt on Dec. 10th, 1977 – a total of 96 days. And then there was the Voyager 2 probe, which launched 15 days after Voyager 1 (on Sept. 20th), but still managed to arrive on the same date – which works out to a total travel time of 81 days.
For Voyager 2, out on the edge of our Solar system, conventional navigation methods don’t work too well. Credit: NASA
Not bad as travel times go. At these speed, a spacecraft could make the trip to the Asteroid Belt, spend several weeks conducting research (or extracting ore), and then make it home in just over six months time. However, one has to take into account that in all these cases, the mission teams did not decelerate the probes to make a rendezvous with any asteroids.
Ergo, a mission to the Asteroid Belt would take longer as the craft would have to slow down to achieve orbital velocity. And they would also need some powerful engines of their own in order to make the trip home. This would drastically alter the size and weight of the spacecraft, which would inevitably mean it would be bigger, slower and a heck of a lot more expensive than anything we’ve sent so far.
Another possibility would be to use ionic propulsion (which is much more fuel efficient) and pick up a gravity assist by conducting a flyby of Mars – which is precisely what the Dawn mission did. However, even with a boost from Mars’ gravity, the Dawn mission still took over three years to reach the asteroid Vesta – launching on Sept. 27th, 2007, and arriving on July 16th, 2011, (a total of 3 years, 9 months, and 19 days). Not exactly good turnaround!
Proposed Future Methods:
A number of possibilities exist that could drastically reduce both travel time and fuel consumption to the Asteroid Belt, many of which are currently being considered for a number of different mission proposals. One possibility is to use spacecraft equipped with nuclear engines, a concept which NASA has been exploring for decades.
The Crew Transfer Vehicle (CTV) using its nuclear-thermal rocket engines to slow down and establish orbit around Mars. Credit: NASA
In a Nuclear Thermal Propulsion (NTP) rocket, uranium or deuterium reactions are used to heat liquid hydrogen inside a reactor, turning it into ionized hydrogen gas (plasma), which is then channeled through a rocket nozzle to generate thrust. A Nuclear Electric Propulsion (NEP) rocket involves the same basic reactor converting its heat and energy into electrical energy, which would then power an electrical engine.
In both cases, the rocket would rely on nuclear fission or fusion to generates propulsion rather than chemical propellants, which has been the mainstay of NASA and all other space agencies to date. According to NASA estimates, the most sophisticated NTP concept would have a maximum specific impulse of 5000 seconds (50 kN·s/kg).
Using this engine, NASA scientists estimate that it would take a spaceship only 90 days to get to Mars when the planet was at “opposition” – i.e. as close as 55,000,000 km from Earth. Adjusted for a distance of 1.2 AUs, that means that a ship equipped with a NTP/NEC propulsion system could make the trip in about 293 days (about nine months and three weeks). A little slow, but not bad considering the technology exists.
Another proposed method of interstellar travel comes in the form of the Radio Frequency (RF) Resonant Cavity Thruster, also known as the EM Drive. Originally proposed in 2001 by Roger K. Shawyer, a UK scientist who started Satellite Propulsion Research Ltd (SPR) to bring it to fruition, this drive is built around the idea that electromagnetic microwave cavities can allow for the direct conversion of electrical energy to thrust.
Artist’s concept of an interstellar craft equipped with an EM Drive. Credit: NASA Spaceflight Center
According to calculations based on the NASA prototype (which yielded a power estimate of 0.4 N/kilowatt), a spacecraft equipped with the EM drive could make the trip to Mars in just ten days. Adjusted for a trip to the Asteroid Belt, so a spacecraft equipped with an EM drive would take an estimated 32.5 days to reach the Asteroid Belt.
Impressive, yes? But of course, that is based on a concept that has yet to be proven. So let’s turn to yet another radical proposal, which is to use ships equipped with an antimatter engine. Created in particle accelerators, antimatter is the most dense fuel you could possibly use. When atoms of matter meet atoms of antimatter, they annihilate each other, releasing an incredible amount of energy in the process.
According to the NASA Institute for Advanced Concepts (NIAC), which is researching the technology, it would take just 10 milligrams of antimatter to propel a human mission to Mars in 45 days. Based on this estimate, a craft equipped with an antimatter engine and roughly twice as much fuel could make the trip to the Asteroid Belt in roughly 147 days. But of course, the sheer cost of creating antimatter – combined with the fact that an engine based on these principles is still theoretical at this point – makes it a distant prospect.
Basically, getting to the Asteroid Belt takes quite a bit of time, at least when it comes to the concepts we currently have available. Using theoretical propulsion concepts, we are able to cut down on the travel time, but it will take some time (and lots of money) before those concepts are a reality. However, compared to many other proposed missions – such as to Europa and Enceladus – the travel time is shorter, and the dividends quite clear.
As already stated, there are enough resources – in the form of minerals and volatiles – in the Asteroid Belt to last us indefinitely. And, should we someday find a way to cost-effective way to send spacecraft there rapidly, we could tap that wealth and begin to usher in an age of post-scarcity! But as with so many other proposals and mission concepts, it looks like we’ll have to wait for the time being.
Artist's impression of the asteroid belt. Image credit: NASA/JPL-Caltech
In the 18th century, observations made of all the known planets (Mercury, Venus, Earth, Mars, Jupiter and Saturn) led astronomers to the realization that there was a pattern in their orbits. Eventually, this led to the Titius–Bode law, which predicted the amount of space that naturally existed between each celestial body that orbited our Sun. In accordance with this law, astronomers noted that there appeared to be a discernible gap between the orbits of Mars and Jupiter.
Investigations into this gap eventually resulted in astronomers observing several bodies of various size. This led to the creation of the term “asteroid” (Greek for ‘star-like’ or ‘star-shaped’), as well as “Asteroid Belt”, once it became clear just how many there were. Through various methods, astronomers have since confirmed the existence of several million objects between the orbit of Mars and Jupiter. They have also determined, with a certain degree of accuracy, how far it is from our planet.
Structure and Composition:
The Asteroid Belt consists of several large bodies, coupled with millions of smaller size. The larger bodies, such as Ceres, Vesta, Pallas, and Hygiea, account for half of the belt’s total mass, with almost one-third accounted for by Ceres alone. Beyond that, over 200 asteroids that are larger than 100 km in diameter, and 0.7–1.7 million asteroids with a diameter of 1 km or more.
The asteroids of the inner Solar System and Jupiter: The donut-shaped asteroid belt is located between the orbits of Jupiter and Mars. Credit: Wikipedia Commons
It total, the Asteroid Belt’s mass is estimated to be 2.8×1021 to 3.2×1021 kilograms – which is equivalent to about 4% of the Moon’s mass. While most asteroids are composed of rock, a small portion of them contain metals such as iron and nickel. The remaining asteroids are made up of a mix of these, along with carbon-rich materials. Some of the more distant asteroids tend to contain more ices and volatiles, which includes water ice.
Despite the impressive number of objects contained within the belt, the Main Belt’s asteroids are also spread over a very large volume of space. As a result, the average distance between objects is roughly 965,600 km (600,000 miles), meaning that the Main Belt consists largely of empty space. In fact, due to the low density of materials within the Belt, the odds of a probe running into an asteroid are now estimated at less than one in a billion.
The main (or core) population of the asteroid belt is sometimes divided into three zones, which are based on what is known as “Kirkwood gaps”. Named after Daniel Kirkwood, who announced in 1866 the discovery of gaps in the distance of asteroids, these gaps are similar to what is seen with Saturn’s and other gas giants’ systems of rings.
Orbit Around the Sun:
Located between Mars and Jupiter, the belt ranges in distance between 2.2 and 3.2 astronomical units (AU) from the Sun – 329 million to 478.7 million km (204.43 million to 297.45 million mi). It is also an estimated 1 AU thick (149.6 million km, or 93 million mi), meaning that it occupies the same amount of distance as what lies between the Earth to the Sun.
The distance of an asteroid from the Sun (its semi-major axis) depends upon its distribution into one of three different zones based on the Belt’s “Kirkwood Gaps”. Zone I lies between the 4:1 resonance and 3:1 resonance Kirkwood gaps, which are roughly 2.06 and 2.5 AUs (3 to 3.74 billion km; 1.86 to 2.3 billion mi) from the Sun, respectively.
Zone II continues from the end of Zone I out to the 5:2 resonance gap, which is 2.82 AU (4.22 billion km; 2.6 mi) from the Sun. Zone III, the outermost section of the Belt, extends from the outer edge of Zone II to the 2:1 resonance gap, located some 3.28 AU (4.9 billion km; 3 billion mi) from the Sun.
Distance from Earth:
The distance between the Asteroid Belt and Earth varies considerably depending on where we measure to. Based on its average distance from the Sun, the distance between Earth and the closest edge of the Belt can be said to be between 1.2 to 2.2 AUs, or 179.5 and 329 million km (111.5 and 204.43 million mi). But of course, at any given time, part of the Asteroid Belt will be on the opposite side of the Sun relative to us as well.
From this vantage point, the distance between Earth and the Asteroid Belt ranges from 3.2 and 4.2 AU – 478.7 to 628.3 million km (297.45 to 390.4 million mi). To put that in perspective, the distance between Earth and the Asteroid Belt ranges from being slightly more than the distance between the Earth and the Sun (1 AU), to being the same as the distance between Earth and Jupiter (4.2 AU) when they are at their closest.
Naturally, any exploration or other kind of mission launched from Earth is going to take the shortest route, unless it is aiming for a specific asteroid. And even then, mission planners will time the launch to ensure that we are closest to the destination. Hence, we can safely use the estimates of 1.2 – 2.2 AU to gauge the distance between us and the Main Belt.
Even so, at its closest, getting to the Asteroid Belt would involve a bit of a hike! In short, it is approximately 179.5 million km (or 111.5 million mi) distant from us at any given time. As such, knowing just how much time and energy it would take to get their and back is going to come in handy if and when we begin mounting crewed missions to the Belt, not to mention the prospect of asteroid mining!
A photo of the full moon, taken from Apollo 11 on its way home to Earth, from about 18,520 km (10,000 nm) away. Credit: NASA
The asteroid that punched an “eye” in the Moon is about 10 times more massive than originally thought. Researchers say a protoplanet-sized body slammed into the Moon about 3.8 billion years ago, creating the area called Imbrium Basin that forms the right eye of the so-called “Man in the Moon.” Additionally, this large body also indicates that protoplanet-sized asteroids may have been common in the early solar system, putting the “heavy” into the Late Heavy Bombardment.
“We show that Imbrium was likely formed by an absolutely enormous object, large enough to be classified as a protoplanet,” said Pete Schultz from Brown University. “This is the first estimate for the Imbrium impactor’s size that is based largely on the geological features we see on the Moon.”
Mare Imbrium or the Sea of Showers is highlighted in this map of the moon. The other large, dark spots are also basins created from asteroid impacts. Credit: NASA
The Imbrium Basin is easily seen when the Moon is full, as a dark patch in the Moon’s northwestern quadrant. It is about 750 miles across, and a closer look shows the basin is surrounded by grooves and gashes that radiate out from the center of the basin, plus a second set of grooves with a different alignment that have puzzled astronomers for decades.
To re-enact the impact, Schultz used the Vertical Gun Range at the NASA Ames Research Center to conduct hypervelocity impact experiments. This facility has a 14-foot cannon that fires small projectiles at up to 25,750 km/hr (16,000 miles per hour), and high-speed cameras record the ballistic dynamics. During his experiments, Schultz noticed that in addition to the usual crater ejecta from the impact, the impactors themselves – if large enough — had a tendency to break apart when they first made contact with the surface. Then these chunks would continue to travel at a high speeds, skimming along and plowing across the surface, creating grooves and gouges.
Grooves and gashes associated with the Imbrium Basin on the Moon have long been puzzling. New research shows how some of these features were formed and uses them to estimate the size of the Imbrium impactor. The study suggests it was big enough to be considered a protoplanet. NASA/Northeast Planetary Data Center/Brown University
The results showed the second set of grooves were likely formed by these large chunks of the impactor that sheared off on initial contact with the surface.
“The key point is that the grooves made by these chunks aren’t radial to the crater,” Schultz said in a press release. “They come from the region of first contact. We see the same thing in our experiments that we see on the Moon — grooves pointing up-range, rather than the crater.”
The second set of groove trajectories could be used to estimate the impactor’s size. Schultz worked with David Crawford of the Sandia National Laboratories to generate computer models of the physics of various sizes of impactors, and they were able to estimate the impactor that created Imbrium Basin to be more than 250 km (150 miles) across, which is two times larger in diameter and 10 times more massive than previous estimates. This puts the impactor in the range of being the size of a protoplanet.
“That’s actually a low-end estimate,” Schultz said. “It’s possible that it could have been as large as 300 kilometers.”
Previous estimates, Schultz said, were based solely on computer models and yielded a size estimate of only about 50 miles in diameter.
Schultz and his colleagues also used the same methods to estimate the sizes of impactors related to several other basins on the Moon, for example, the Moscoviense and Orientale basins on the Moon’s far side, which yielded impactor sizes of 100 and 110 kilometers across respectively, larger than some previous estimates.
Combining these new estimates with the fact that there are even larger impact basins on the Moon and other planets, Schultz concluded that protoplanet-sized asteroids may have been common in the early solar system, and he called them the “lost giants” of the Late Heavy Bombardment, a period of intense comet and asteroid bombardment thought to have pummeled the Moon and all the planets including the Earth about 4 to 3.8 billion years ago.
“The Moon still holds clues that can affect our interpretation of the entire solar system,” he said. “Its scarred face can tell us quite a lot about what was happening in our neighborhood 3.8 billion years ago.”
New Horizons trajectory and the orbits of Pluto and 2014 MU69.
New Horizons trajectory and the orbits of Pluto and 2014 MU69.
In an ‘Independence Day’ gift to a slew of US planetary research scientists, NASA has granted approval to nine ongoing missions to continue for another two years this holiday weekend.
The biggest news is that NASA green lighted a mission extension for the New Horizons probe to fly deeper into the Kuiper Belt and decided to keep the Dawn probe at Ceres forever, rather than dispatching it to a record breaking third main belt asteroid.
And the exciting extension news comes just as the agency’s Juno probe is about to ignite a do or die July 4 fireworks display to achieve orbit at Jupiter – detailed here.
“Mission approved!” the researchers gleefully reported on the probes Facebook and Twitter social media pages.
“Our extended mission into the #KuiperBelt has been approved. Thanks to everyone for following along & hopefully the best is yet to come.
Dwarf planet Ceres is shown in this false-color renderings, which highlight differences in surface materials. The image is centered on Ceres brightest spots at Occator crater. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The New Horizons spacecraft will now continue on course in the Kuiper Belt towards an small object known as 2014 MU69, to carry out the most distant close encounter with a celestial object in human history.
“Here’s to continued success!”
The spacecraft will rendezvous with the ancient rock on New Year’s Day 2019.
Researchers say that 2014 MU69 is considered as one of the early building blocks of the solar system and as such will be invaluable to scientists studying the origin of our solar system how it evolved.
It was almost exactly one year ago on July 14, 2015 that New Horizons conducted Earth’s first ever up close flyby and science reconnaissance of Pluto – the most distant planet in our solar system and the last of the nine planets to be explored.
Pluto Explored at Last. The New Horizons mission team celebrates successful flyby of Pluto in the moments after closest approach at 7:49 a.m. EDT on July 14, 2015. New Horizons Principal Investigator Alan Stern of Southwest Research Institute (SwRI), Boulder, CO., left, Johns Hopkins University Applied Physics Laboratory (APL) Director Ralph Semmel, center, and New Horizons Co-Investigator Will Grundy Lowell Observatory hold an enlarged print of an U.S. stamp with their suggested update after Pluto became the final planet in our solar system to be explored by an American space probe (crossing out the words ‘not yet’) – at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. Credit: Ken Kremer/kenkremer.com
The immense volume of data gathered continues to stream back to Earth every day.
“The New Horizons mission to Pluto exceeded our expectations and even today the data from the spacecraft continue to surprise,” said NASA’s Director of Planetary Science Jim Green at NASA HQ in Washington, D.C.
“We’re excited to continue onward into the dark depths of the outer solar system to a science target that wasn’t even discovered when the spacecraft launched.”
This new global mosaic view of Pluto was created from the latest high-resolution images to be downlinked from NASA’s New Horizons spacecraft and released on Sept. 11, 2015. The images were taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). This new mosaic was stitched from over two dozen raw images captured by the LORRI imager and colorized. Annotated with informal place names. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
While waiting for news on whether NASA would approve an extended mission, the New Horizons engineering and science team already ignited the main engine four times to carry out four course changes in October and November 2015, in order to preserve the option of the flyby past 2014 MU69 on Jan 1, 2019.
Green noted that mission extensions into fiscal years 2017 and 2018 are not final until Congress actually passes sufficient appropriation to fund NASA’s Planetary Science Division.
“Final decisions on mission extensions are contingent on the outcome of the annual budget process.”
Tough choices were made even tougher because the Obama Administration has cut funding for the Planetary Sciences Division – some of which was restored by a bipartisan majority in Congress for what many consider NASA’s ‘crown jewels.’
NASA’s Dawn asteroid orbiter just completed its primary mission at dwarf planet Ceres on June 30, just in time for the global celebration known as Asteroid Day.
“The mission exceeded all expectations originally set for its exploration of protoplanet Vesta and dwarf planet Ceres,” said NASA officials.
The Dawn science team had recently submitted a proposal to break out of orbit around the middle of this month in order to this conduct a flyby of the main belt asteroid Adeona.
Green declined to approve the Dawn proposal, citing additional valuable science to be gathered at Ceres.
The long-term monitoring of Ceres, particularly as it gets closer to perihelion – the part of its orbit with the shortest distance to the sun — has the potential to provide more significant science discoveries than a flyby of Adeona,” he said.
The funding required for a multi-year mission to Adeona would be difficult in these cost constrained times.
However the spacecraft is in excellent shape and the trio of science instruments are in excellent health.
Dawn arrived at Ceres on March 6, 2015 and has been conducting unprecedented investigation ever since.
Dawn is Earth’s first probe in human history to explore any dwarf planet, the first to explore Ceres up close and the first to orbit two celestial bodies.
The asteroid Vesta was Dawn’s first orbital target where it conducted extensive observations of the bizarre world for over a year in 2011 and 2012.
The mission is expected to last until at least later into 2016, and possibly longer, depending upon fuel reserves.
Due to expert engineering and handling by the Dawn mission team, the probe unexpectedly has hydrazine maneuvering fuel leftover.
Dawn will remain at its current altitude at the Low Altitude Mapping Orbit (LAMO) for the rest of its mission, and indefinitely afterward, even when no further communications are possible.
Green based his decision on the mission extensions on the biannual peer review scientific assessment by the Senior Review Panel.
Dawn was launched in September 2007.
The other mission extensions – contingent on available resources – are: the Mars Reconnaissance Orbiter (MRO), Mars Atmosphere and Volatile EvolutioN (MAVEN), the Opportunity and Curiosity Mars rovers, the Mars Odyssey orbiter, the Lunar Reconnaissance Orbiter (LRO), and NASA’s support for the European Space Agency’s Mars Express mission.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
The surface patterns on one of the microscopic dust particles from asteroid Itokawa. Image: JAXA
In 2003, the Japanese Aerospace Exploration Agency (JAXA) launched the Hayabusa probe. Its mission was to rendezvous with asteroid 25143 Itokawa in 2005. Once there, it studied a number of things about Itokawa, including its shape, topography, composition, colour, spin, density, and history. But the most exciting part of its mission was to collect samples from the asteroid and return them to Earth.
The mission suffered some complications, including the failure of Minerva, Hayabusa’s detachable mini-lander. But Hayabusa did land on the asteroid, and it did collect some samples; tiny grains of material from the surface of Itokawa. This was the first time a mission had landed somewhere and returned samples, other than missions to the Moon.
The Hayabusa spacecraft burned up on re-entry into Earth’s atmosphere, but the capsule containing the samples survived. The glowing piece on the bottom front of the debris stream is the sample capsule. Image: NASA Ames, Public Domain
Once the collected grains made it back to Earth in 2010, and were confirmed to be from the asteroid, scientists got excited. These grains would be key to helping understand the early Solar System when the planetary bodies were formed. And they have revealed a sometimes violent history going back 4.5 billion years.
The grains themselves are truly microscopic, at just over 10 micrometers in size. The marks and surface patterns on them are measured in nanometers. Initially, all the marks on the surfaces of the particles were thought to be of one type. But the team behind the study used electron microscopes and X-Ray Microtomography to reveal four different types of patterns on their surfaces.
One 4.5 billion year old pattern shows crystallization from intense heat. At this time period, Itokawa was part of a larger asteroid. The second pattern indicates a collision with a meteor about 1.3 billion years ago. Another pattern was formed by exposure to the solar wind between 1 million and 1,000 years ago. A fourth pattern detected by scientists shows that the particles have been rubbing against each other.
The team has concluded that Itokawa didn’t always exist in its current shape and form. When it was formed over 4 billion years ago, it was about 40 times bigger than it is now. That parent body was destroyed, and the researchers think that Itokawa re-formed from fragments of the parent body.
If there is still any lingering doubt about the violent nature of the Solar System’s history, the grains from Itokawa help dispel it. Collision, fragmentation, bombardments, and of course solar wind, seem to be the norm in our Solar System’s history.
The return of these samples was a bit of a happy accident. The sample collection mechanism on Hayabusa suffered a failure, and the returned dust grains were actually kicked up by the landing of the probe, and some ended up in the sample capsule.
For their part, JAXA has already launched Hayabusa’s successor, Hayabusa 2. It was launched in December 2014, and is headed for asteroid 162173 Ryugu. It should reach its destination in July 2018, and spend a year and a half there. Hayabusa 2 is also designed to collect asteroid samples and return them to Earth, this time using an explosive device to dig into the asteroid’s surface for a sample. Hayabusa 2 should return to Earth in December 2020.
An artist’s image of Hayabusa leaving Earth. Image credit: JAXA
Hayabusa suffered several failures, including the failure of its mini-lander, problems with sample collection, and it even suffered damaged to its solar panels caused by a solar flare, which reduced its power and delayed its arrival at Itokawa. Yet it still ended up being a success in the end.
If Hayabusa 2 can avoid some of these problems, who knows what we may learn from more intentional samples. Sample missions are tricky and complex. If Hayabusa can return samples, it would be only the fourth body to have samples successfully returned to Earth, including the Moon, asteroid Itokawa, and comet Wild 2.
Artist's impression of what the rings of the asteroid Chariklo would look like from the small body's surface. The rings' discovery was a first for an asteroid. Credit: ESO/L. Calçada/Nick Risinger (skysurvey.org)
When we think of ring systems, what naturally comes to mind are planets like Saturn. It’s beautiful rings are certainly the most well known, but they are not the only planet in our Solar System to have them. As the Voyager missions demonstrated, every planet in the outer Solar System – from Jupiter to Neptune – has its own system of rings. And in recent years, astronomers have discovered that even certain minor planets – like the Centaur asteroids 10199 Chariklo and 2006 Chiron – have them too.
This was a rather surprising find, since these objects have such chaotic orbits. Given that their paths through the Solar System are frequently altered by the powerful gravity of gas giants, astronomers have naturally wondered how a minor planet could retain a system of rings. But thanks to a team of researchers from the Sao Paulo State University in Brazil, we may be close to answering that question.
In a study titled “The Rings of Chariklo Under Close Encounters With The Giant Planets“, which appeared recently in The Astrophysical Journal, they explained how they constructed a model of the Solar System that incorporated 729 simulated objects. All of these objects were the same size as Chariklo and had their own system of rings. They then went about the process of examining how interacting with gas giant effected them.
Artist’s impression of rings around the Centaur Chariklo, the first asteroid where rings were discovered. Credit: ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)
To break it down, Centaurs are a population of objects within our Solar System that behave as both comets and asteroids (hence why they are named after the hybrid beasts of Greek mythology). 10199 Chariklo is the largest known member of the Centaur population, a possible former Trans-Neptunian Object (TNO) which currently orbitsbetween SaturnandUranus.
The rings around this asteroid were first noticed in 2013 when the asteroid underwent a stellar occultation. This revealed a system of two rings, with a radius of 391 and 405 km and widths of about 7 km 3 km, respectively. The absorption features of the rings showed that they were partially composed of water ice. In this respect, they were much like the rings of Jupiter, Saturn, Uranus and the other gas giants, which are composed largely of water ice and dust.
This was followed by findings made in 2015 that indicated that 2006 Chiron – another major Centaur – could have a ring of its own. This led to further speculation that there might be many minor planets in our Solar System that have a system of rings. Naturally, this was a bit perplexing to astronomers, since rings are fragile structures that were thought to be exclusive to the gas giants of our System.
As Professor Othon Winter, the lead researcher of the Sao Paulo team, told Universe Today via email:
“At first it was a surprise to find a Centaur with rings, since the Centaurs have chaotic orbits wandering between the giant planets and having frequent close encounters with them. However, we have shown that in most of the cases the ring system can survive all the close encounters with the giant planets. Therefore, Centaurs with rings might be much more common than we thought before.”
Artist’s impression of Chiron, showing a possible ring system. Credit: dailygalaxy.com
For the sake of their study, Winter and his colleagues considered the orbits of 729 simulated clones of Chariklo as they orbited the Sun over the course of 100 million years. From this, Winter and his colleagues found that each Centaur averaged about 150 close encounters with a gas giant, within one Hill radius of the planet in question. As Winter described it:
“The study was made in two steps. First we considered a set of more than 700 clones of Chariklo. The clones had initial trajectories that were slightly different from Chariklo for statistical purposes (since we are dealing with chaotic trajectories) and computationally simulated their orbital evolution forward in time (to see their future) and also backward in time (to see their past). During these simulations we archived the information of all the close encounters (many thousands) they had with each of the giant planets.”
“In the second step, we performed simulations of each one of the close encounters found in the first step, but now including a disk of particles around Chariklo (representing the ring particles). Then, at the end of each simulation we analyzed what happened to the particles. Which ones were removed from Chariklo (escaping its gravitational field)? Which ones were strongly disturbed (still orbiting around Chariklo)? Which ones did not suffer any significant effect?”
In the end, the simulations showed that in 90 percent of the cases, the rings of the Centaurs survived their close encounters with gas giants, whereas they were disturbed in 4 percent of cases, and were stripped away only 3 percent of the time. Thus, they concluded that if there is an efficient mechanism that creates the rings, then it is strong enough to let Centaurs keep them.
Due to their dual nature, the name Centaur has stuck when referring to objects that act as both comets and asteroids. Credit: jpl.nasa.gov
More than that, their research would seem to indicate that what was considered unique to certain planetary bodies may actually be more commonplace. “It reveals that our Solar System is complex not just as whole or for large bodies,” said Winter, “but even small bodies may show complex structures and even more complex temporal evolution.”
The next step for the research team is to study ring formation, which could show that they in fact picking them up from the gas giants themselves. But regardless of where they come from, its becoming increasingly clear that Centaurs like 10199 Chariklo are not alone. What’s more, they aren’t giving up their rings anytime soon!
