Artists concept of a shredded asteroid getting too close to a star. (NASA/JPL-Caltech)
The Sun has enormous destructive power. Any objects that collide with the Sun, such as comets and asteroids, are immediately destroyed.
But now we’re finding that the Sun has the ability to reach out and touch asteroids at a far greater distance than previously thought. The proof of this came when a team at the University of Hawaii Institute of Astronomy was looking at Near-Earth Objects (NEOs) catalogued by the Catalina Sky Survey, and trying to understand what asteroids might be missing from that survey.
An asteroid is classified as an NEO when, at its closest point to the Sun, it is less than 1.3 times the distance from the Earth to the Sun. We need to know where these objects are, how many of them there are, and how big they are. They’re a potential threat to spacecraft, and to Earth itself.
The 60 inch Mt. Lemmon telescope is one of three telescopes used in the Catalina Sky Survey. Image: Catalina Sky Survey, University of Arizona.
The Catalina Sky Survey (CSS) detected over 9,000 NEOs in eight years. But asteroids are notoriously difficult to detect. They are tiny points of light, and they’re moving. The team knew that there was no way the CSS could have detected all NEOs, so Dr. Robert Jedicke, a team member from the University of Hawaii Institute of Astronomy, developed software that would tell them what CSS had missed in its survey of NEOs.
This took an enormous amount of work—and computing power—and when it was completed, they noticed a discrepancy: according to their work, there should be over ten times as many objects within ten solar diameters of the Sun as they found. The team had a puzzle on their hands.
The team spent a year verifying their work before concluding that the problem did not lay in their analysis, but in our understanding of how the Solar System works. University of Helsinki scientist Mikael Granvik, lead author of the Nature article that reported these results, hypothesized that their model of the NEO population would better suit their results if asteroids were destroyed at a much greater distance from the sun than previously thought.
They tested this idea, and found that it agreed with their model and with the observed population of NEOs, once asteroids that spent too much time within 10 solar diameters of the Sun were eliminated. “The discovery that asteroids must be breaking up when they approach too close to the Sun was surprising and that’s why we spent so much time verifying our calculations,” commented Dr. Jedicke.
There are other discrepancies in our Solar System between what is observed and what is predicted when it comes to the distribution of small objects. Meteors are small pieces of dust that come from asteroids, and when they enter our atmosphere they burn up and make star-gazing all the more eventful. Meteors exist in streams that come from their parent objects. The problems is, most of the time the streams can’t be matched with their parent object. This study shows that the parent objects must have been destroyed when they got too close to the Sun, leaving behind a stream of meteors, but no apparent source.
There was another surprise in store for the team. Darker asteroids are destroyed at a greater distance from the Sun than lighter ones are. This explains an earlier discovery, which showed that brighter NEOs travel closer to the Sun than darker ones do. If darker asteroids are destroyed at a greater distance from the Sun than their lighter counterparts, then the two must have differing compositions and internal structure.
“Perhaps the most intriguing outcome of this study is that it is now possible to test models of asteroid interiors simply by keeping track of their orbits and sizes. This is truly remarkable and was completely unexpected when we first started constructing the new NEO model,” says Granvik.
Asteroids represent a real danger to Earth. But is targeting them with missiles, maybe nuclear, a good idea? Image: NASA/JPL/CalTech
In a shocking announcement, Russian scientists say they want to test improved ballistic missiles on the asteroid Apophis, which is expected to come dangerously close to Earth in 2036. If this doesn’t send chills down your spine, you haven’t read enough science fiction.
In a February 11th article in the Russian state-owned news agency TASS, Sabit Saitgarayev, the lead researcher at the Makeyev Rocket Design Bureau, says Russian scientists are developing a program to upgrade Inter-Continental Ballistic Missiles (ICBMs) to destroy near-Earth meteors from 20-50 metres in size. Apophis’ approach in 2036 would be a test for this program.
ICBM’s are the kind of long range nukes that the USSR and the USA had pointed at each other for decades during the Cold War. They still have some pointed at each other, and they can be launched quickly. This program would take that technology and improve it for anti-asteroid use.
Typical rockets of the type that take payloads into space are not good candidates for intercepting asteroids. They require too much lead time to meet the threat of an incoming asteroid that might be detected only days before impact. They can take several days to fuel. But ICBM’s are different. They can stand at the ready for long periods of time, and be launched at a moment’s notice. But to be suitable for use as asteroid killers, they have to be upgraded.
Design work on the asteroid-killing ICBM’s has already begun, admitted Saitgarayev, but he did not say whether the money has been committed or whether the authorization has been given to go ahead with the project. But like a lot of things that are said and done by Russia, it’s difficult to know exactly where the truth lies.
There’s no question that being prepared to prevent an asteroid strike on Earth is of the utmost importance. No matter where on Earth one was to strike, the effects could be global. But one thing’s certain: the development and testing of missiles designed to be used in space is unsettling.
It’s also unsettling in light of the January 16th TASS article stating that “The international scientific community has asked Russian scientists to develop an asteroid deflection system on the basis of nuclear explosions in space.” Taken together, the two announcements point towards a program of weaponizing space, something the international community has agreed should be avoided. In fact, there is a ban on nuclear explosions in space.
We don’t want to be alarmist. There are only a handful of countries in the world that have the capacity to develop some protective system against asteroids, and Russia is definitely one of them. And if Earth were threatened by an asteroid, the weaponization of space would be the least of our concerns.
The fact that Russia wants to develop a missile system with nuclear warheads, and employ it in space, is not entirely unreasonable. But it should make us stop and think. What will happen if something goes wrong?
It’s easy to imagine a scenario where an atomic explosion went off in low-Earth orbit. What would the consequences be? And what are the consequences to having one country develop this capability, rather than an international group? How can this whole endeavour be managed responsibly?
Artist's impression of a Near-Earth Asteroid passing by Earth. Credit: ESA
On October 6th, 2013, the Catalina Sky Survey discovered a small asteroid which was later designated as 2013 TX68. As part Apollo group this 30 meter (100 ft) rock is one of many Near-Earth Objects (NEOs) that periodically crosses Earth’s orbit and passes close to our planet. A few years ago, it did just that, flying by our planet at a safe distance of about 2 million km (1.3 million miles).
And according to NASA’s Center for NEO Studies (CNEOS) at the Jet Propulsion Laboratory, it will be passing us again in a few weeks time, specifically between March 2nd and 6th. Of course, asteroids pass Earth by on a regular basis, and there is very rarely any cause for alarm. However, there is some anxiety about 2013 TX68’s latest flyby, mainly because its distance could be subject to some serious variation.
Special Guest: Dr. Stuart Robbins, Research Scientist at Southwest Research Institute (SwRI); Mars Impact Craters, Science Lead on Moon Mappers and Mercury Mappers.
Phobos and Deimos, photographed here by the Mars Reconnaissance Orbiter, are tiny, irregularly-shaped moons that are probably strays from the main asteroid belt. Credit: NASA - See more at: http://astrobob.areavoices.com/2013/07/05/rovers-capture-loony-moons-and-blue-sunsets-on-mars/#sthash.eMDpTVPT.dpuf
Many of the planets in our Solar System have a system of moons. But among the rocky planets that make up the inner Solar System, having moons is a privilege enjoyed only by two planets: Earth and Mars. And for these two planets, it is a rather limited privilege compared to gas giants like Jupiter and Saturn which each have several dozen moons.
Whereas Earth has only one satellite (aka. the Moon), Mars has two small moons in orbit around it: Phobos and Deimos. And whereas the vast majority of moons in our Solar System are large enough to become round spheres similar to our own Moon, Phobos and Deimos are asteroid-sized and misshapen in appearance.
Gerard Kuiper, founder of the Lunar and Planetary Laboratory. Credit: lpl.arizona.edu
In the outer reaches of the Solar System, beyond the orbit of Neptune, lies a region permeated by celestial objects and minor planets. This region is known as the “Kuiper Belt“, and is named in honor of the 20th century astronomer who speculated about the existence of such a disc decades before it was observed. This disc, he reasoned, was the source of the Solar Systems many comets, and the reason there were no large planets beyond Neptune.
Gerard Kuiper is also regarded by many as being the “father of planetary science”. During the 1960s and 70s, he played a crucial role in the development of infrared airborne astronomy, a technology which led to many pivotal discoveries that would have been impossible using ground-based observatories. At the same time, he helped catalog asteroids, surveyed the Moon, Mars and the outer Solar System, and discovered new moons.
Europa is probably the best place in the Solar System to go searching for life. But before they’re launched, any spacecraft we send will need to be squeaky clean so don’t contaminate the place with our filthy Earth bacteria. Continue reading “Will We Contaminate Europa?”
Robotic sampling arm and capture mechanism to collect a multi-ton boulder from an asteroid are under development at NASA Goddard and other agency centers for NASA’s unmanned Asteroid Redirect Vehicle and eventual docking in lunar orbit with Orion crew vehicle by the mid 2020s. Credit: Ken Kremer/kenkremer.com
NASA GODDARD SPACE FLIGHT CENTER, MD – Rigorous testing has begun on the advanced robotic arm and boulder extraction mechanisms that are key components of the unmanned probe at the heart of NASA’s Asteroid Redirect Robotic Mission (ARRM) now under development to pluck a multi-ton boulder off a near-Earth asteroid so that astronauts visiting later in an Orion crew capsule can harvest a large quantity of samples for high powered scientific analysis back on Earth. Universe Today inspected the robotic arm hardware utilizing “leveraged robotic technology” during an up close visit and exclusive interview with the engineering development team at NASA Goddard.
“The teams are making great progress on the capture mechanism that has been delivered to the robotics team at Goddard from Langley,” NASA Associate Administrator Robert Lightfoot told Universe Today.
“NASA is developing these common technologies for a suite of missions like satellite servicing and refueling in low Earth orbit as well as autonomously capturing an asteroid about 100 million miles away,” said Ben Reed, NASA Satellite Servicing Capabilities Office (SSCO) Deputy Project Manager, during an exclusive interview and hardware tour with Universe Today at NASA Goddard in Greenbelt, Maryland, regarding concepts and goals for the overall Asteroid Redirect Mission (ARM) initiative.
NASA is leveraging technology originally developed for satellite servicing such as with the Robotic Refueling Mission (RRM) currently on board the International Space Station(ISS) and repurposing them for the asteroid retrieval mission.
“Those are our two near term mission objectives that we are developing these technologies for,” Reed explained.
The unmanned Asteroid Redirect Robotic Mission (ARRM) to grab a boulder is the essential first step towards carrying out the follow on sample retrieval with the manned Orion Asteroid Redirect Mission (ARM) by the mid-2020s.
ARRM will use a pair of highly capable robotic arms to autonomously grapple a multi-ton (> 20 ton) boulder off the surface of a large near-Earth asteroid and transport it to a stable, astronaut accessible orbit around the Moon in cislunar space.
“Things are moving well. The teams have made really tremendous progress on the robotic arm and capture mechanism,” Bill Gerstenmaier, NASA Associate Administrator for Human Exploration and Operations, told Universe Today.
Then an Orion crew capsule can fly to it and the astronauts will collect a large quantity of rock samples and gather additional scientific measurements.
“We are working on a system to rendezvous, capture and service different [target] clients using the same technologies. That is what we are working on in a nut shell,” Reed said.
This engineering design unit of the robotic servicing arm is under development to autonomously extract a boulder off an asteroid for NASA’s asteroid retrieval mission and is being tested at NASA Goddard. It has seven degrees of freedom and mimics a human arm. Credit: Ken Kremer/kenkremer.com
“Right now the plan is to launch ARRM by about December 2020,” Reed told me. But a huge amount of preparatory work across the US is required to turn NASA’s plan into reality.
Key mission enabling technologies are being tested right now with a new full scale engineering model of the ‘Robotic Servicing Arm’ and a full scale mockup of the boulder snatching ARRM Capture Module at NASA Goddard, in a new facility known as “The Cauldron.”
Capture Module comprising two robotic servicing arms and three boulder grappling contact and restraint system legs for NASA’s Asteroid Redirect Robotic Mission (ARRM). Credit: NASAThe ARRM capture module is comprised of two shorter robotic arms (separated by 180 degrees) and three lengthy contact and restraint system capture legs (separated by 120 degrees) attached to a cradle with associated avionics, computers and electronics and the rest of the spacecraft and solar electric power arrays.
“The robotic arm we have here now is an engineering development unit. The 2.2 meter-long arms can be used for assembling large telescopes, repairing a failed satellite, removing orbital debris and capturing an asteroid,” said Reed.
“There are two little arms and three big capture legs.”
“So, we are leveraging one technology development program into multiple NASA objectives.”
“We are working on common technologies that can service a legacy orbiting satellite, not designed to be serviced, and use those same technologies with some tweaking that we can go out with 100 million miles and capture an asteroid and bring it back to the vicinity of the Moon.”
“Currently the [capture module] system can handle a boulder that’s up to about 3 x 4 x 5 meters in diameter.”
Artists concept of NASA’s Asteroid Redirect Robotic Mission capturing an asteroid boulder before redirecting it to a astronaut-accessible orbit around Earth’s moon. Credits: NASA
The Cauldron is a brand new Goddard facility for testing technologies and operations for multiple exploration and science missions, including satellite servicing and ARRM that just opened in June 2015 for the centers Satellite Servicing Capabilities Office.
Overall project lead for ARRM is the Jet Propulsion Laboratory (JPL) with numerous contributions from other NASA centers and industrial partners.
“This is an immersive development lab where we bring systems together and can do lifetime testing to simulate what’s in space. This is our robotic equivalent to the astronauts NBL, or neutral buoyancy lab,” Reed elaborated.
“So with this same robotic arm that can cut wires and thermal blankets and refuel an Earth sensing satellite, we can now have that same arm go out on a different mission and be able to travel out and pick up a multi-ton boulder and bring it back for astronauts to harvest samples from.”
“So that’s quite a technical feat!”
The Robotic Servicing Arm is a multi-jointed powerhouse designed to function like a “human arm” as much as possible. It builds on extensive prior research and development investment efforts conducted for NASA’s current Red Planetrovers and a flight-qualified robotic arm developed for the Defense Advanced Research Projects Agency (DARPA).
“The arm is capable of seven-degrees-of-freedom to mimic the full functionally of a human arm. It has heritage from the arm on Mars right now on Curiosity as well as ground based programs from DARPA,” Reed told me.
“It has three degrees of freedom at our shoulder, two at our elbow and two more at the wrist. So I can hold the hand still and move the elbow.”
The arm will also be equipped with a variety of interchangeable “hands” that are basically tools to carry out different tasks with the asteroid such as grappling, drilling, sample gathering, imaging and spectrometric analysis, etc.
View of the robotic arm above and gripper tool below that initially grabs the asteroid boulder before the capture legs wrap around as planned for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will later dock with an Orion crew vehicle. Credit: Ken Kremer/kenkremer.com
The ARRM spacecraft will carefully study, characterize and photograph the asteroid in great detail for about a month before attempting the boulder capture.
Why does the arm need all this human-like capability?
“When we arrive at an asteroid that’s 100 million miles away, we are not going to know the fine local geometry until we arrive,” Reed explained to Universe Today.
“Therefore we need a flexible enough arm that can accommodate local geometries at the multi-foot scale. And then a gripper tool that can handle those geometry facets at a much smaller scale.”
“Therefore we chose seven-degrees-of-freedom to mimic humans very much by design. We also need seven-degrees-of-freedom to conduct collision avoidance maneuvers. You can’t do that with a six-degree-of-freedom arm. It has to be seven to be a general purpose arm.”
How will the ARRM capture module work to snatch the boulder off the asteroid?
“So the idea is you come to the mother asteroid and touch down and make contact on the surface. Then you hold that position and the two arms reach out and grab the boulder.”
“Once its grabbed the boulder, then the legs straighten and pull the boulder off the surface.”
“Then the arms nestle the asteroid onto a cradle. And the legs then change from a contact system to become a restraint system. So the legs wrap around the boulder to restrain it for the 100 million mile journey back home.
“After that the little arms can let go – because the legs have wrapped around and are holding the asteroid.”
“So now the arm can also let go of the gripper system and pick up a different tool to do other things. For example they can collect a sample with another tool. And maybe assist an astronaut after the crew arrives.”
“During the 100 million mile journey back to lunar orbit they can be also be preparing the surface and cutting into it for later sample collection by the astronauts.”
Be sure to watch this video animation:
Since the actual asteroid encounter will occur very far away, the boulder grappling will have to be done fully autonomously since there will be no possibility for real time communications.
“The return time for communications is like about 30 minutes. So ‘human in the loop’ control is out of the question.
“Once we get into hover position over the landing site we hit the GO button. Then it will be very much like at Mars and the seven minutes of terror. It will take awhile to find out if it worked.”
Therefore the team at Goddard has already spent years of effort and practice sessions just to get ready for working with the early engineering version of the arm to maximize the probability of a successful capture.
“In this facility we put systems together to try and practice and rehearse and simulate as much of the mission as is realistically possible.”
“It took a lot of effort to get to this point, in the neighborhood of four years to get the simulation to behave correctly in real time with contact dynamics and the robotic systems. So the arm has to touch the boulder with force torque sensors and feed that into a computer to measure that and move the actuators to respond accordingly.”
“So the capture of the boulder is autonomous. The rest is teleoperated from the ground, but not the capture itself.”
How realistic are the rehearsals?
“We are practicing here by reaching out with the arm to grasp the client target using autonomous capture [procedures]. In space the client [target] is floating and maybe tumbling. So when we reach out with the arm to practice autonomous capture we make the client tumble and move – with the inertial properties of the target we are practicing on.”
“Now for known objects like satellites we know the mass precisely. And we can program all that inertial property data in very accurately to give us much more realistic simulations.”
“We learned from all our astronaut servicing experiences in orbit is that the more we know for the simulations, the easier and better the results are for the astronauts during an actual mission because you simulated all the properties.”
“But with this robotic mission to an asteroid there is no backup like astronauts. So we want to practice here at Goddard and simulate the space environment.”
ARRM will launch by the end of 2020 on either an SLS, Delta IV Heavy or a Falcon Heavy. NASA has not yet chosen the launch vehicle.
Several candidate asteroids have already been discovered and NASA has an extensive ongoing program to find more.
Orion crew capsule docks to NASA’s asteroid redirect vehicle grappling captured asteroid boulder orbiting the Moon. Credit: NASA
Again, this robotic technology was selected for development for ARRM because it has a lot in common with other objectives like fixing communications satellites, refueling satellites and building large telescopes in the future.
NASA is also developing other critical enabling technologies for the entire ARM project like solar electric propulsion that will be the subject of another article.
Therefore NASA is leveraging one technology development program into multiple spaceflight objectives that will greatly assist its plans to send ‘Humans to Mars’ in the 2030s with the Orion crew module launched by the monster Space Launch System (SLS) rocket.
The maiden uncrewed launch of the Orion/SLS stack is slated for November 2018.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
At NASA Goddard robotics lab Ben Reed/NASA Satellite Servicing Capabilities Office (SSCO) Deputy Project Manager and Ken Kremer/Universe Today discuss the robotic servicing arm and asteroid boulder capture mechanism being tested for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will dock with an Orion crew vehicle in lunar orbit by the mid 2020s for sample return collection. Credit: Ken Kremer/kenkremer.com
The high gain antenna and solar arrays were installed on the OSIRIS-REx spacecraft prior to it moving to environmental testing. Credits: Lockheed Martin Corporation
OSIRIS-Rex, the first American spacecraft ever aimed at snatching pristine samples from the surface of an asteroid and returning them to Earth for exquisite analysis by researchers world-wide with the most advanced science instruments has successfully completed its assembly phase and moved into the “test drive” phase – just ten months before blastoff, following installation of all its science instruments at Lockheed Martin Space Systems facilities, near Denver, Colorado.
The launch window for OSIRIS-REx opens next fall on September 3, 2016 on a seven-year journey to asteroid Bennu and back. Bennu is a carbon-rich asteroid. OSIRIS-Rex will eventually return the largest sample from space since the American and Soviet Union’s moon landing missions of the 1970s.
The science payload installation was recently completed with attachment of the vehicles three camera instrument suite of cameras and spectrometers known as OCAMS (OSIRIS-REx Camera Suite), which was was designed and built by the University of Arizona’s Lunar and Planetary Laboratory.
OCAMS trio of instruments, PolyCam, MapCam and SamCam, will survey and globally map the surface of Bennu up close at a distance ranging from approximately 5 km to 0.7 km.
“PolyCam, MapCam and SamCam will be our mission’s eyes at Bennu,” said Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona, Tucson, in a statement.
“OCAMS will provide the imagery we need to complete our mission while the spacecraft is at the asteroid.”
“All in all it was flawless installation, with the three cameras and the control electronics making it on the spacecraft well in advance of when we originally planned these activities. In general, the OSIRIS-REx ATLO (assembly, test and launch operations) flow has gone smoothly,” said Lauretta in a blog update.
The 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
For the next five months, NASA’s OSIRIS-REx which stands for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer will undergo a rigorous regime of critical environmental testing to ensure the probe will survive the unforgiving extremes of vacuum, vibration and extreme temperatures it will experience during launch and throughout the life of its planned eight year mission.
The asteroid sampling spacecraft is tracking on budget and ahead of schedule.
“OSIRIS-REx is entering environmental testing on schedule, on budget and with schedule reserves,” said Mike Donnelly, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in a statement.
“This allows us to have flexibility if any concerns arise during final launch preparations.”
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,” says NASA.
The spacecraft is equipped with a suite of five science instruments to remotely study the 492 meter wide asteroid.
The instruments were all installed as planned on the spacecraft deck over the past few months so they can all be subjected to the environmental testing together with the spacecraft bus.
“This milestone marks the end of the design and assembly stage,” said Lauretta, in a statement.
“We now move on to test the entire flight system over the range of environmental conditions that will be experienced on the journey to Bennu and back. This phase is critical to mission success, and I am confident that we have built the right system for the job.”
The tests will “simulate the harsh environment of space, including acoustical, separation and deployment shock, vibration, and electromagnetic interference. The simulation concludes with a test in which the spacecraft and its instruments are placed in a vacuum chamber and cycled through the extreme hot and cold temperatures it will face during its journey to Bennu,” say NASA officials.
Video caption: Engineers at Lockheed Martin move the OSIRIS-REx spacecraft onto a rotation fixture. This fixture supports the full weight of the spacecraft and acts as a hinge, orienting the spacecraft at a 90 degree angle, which allows engineers to access the top of the spacecraft much more easily. Credits: Lockheed Martin Corporation
The testing is done to uncover any issues lurking prior next September’s planned liftoff.
“This is an exciting time for the program as we now have a completed spacecraft and the team gets to test drive it, in a sense, before we actually fly it to asteroid Bennu,” said Rich Kuhns, OSIRIS-REx program manager at Lockheed Martin Space Systems.
“The environmental test phase is an important time in the mission as it will reveal any issues with the spacecraft and instruments, while here on Earth, before we send it into deep space.”
After the testing is complete by next May, the spacecraft will ship from Lockheed Martin’s Denver facility to NASA’s Kennedy Space Center, where it will undergo final prelaunch preparations and transport to the launch pad at Cape Canaveral.
Artist concept of OSIRIS-REx, the first U.S. mission to return samples from an asteroid to Earth. Credit: NASA/Goddard
OSIRIS-REx is scheduled for launch in September 2016 from Cape Canaveral Air Force Station in Florida aboard a United Launch AllianceAtlas V 411 rocket, which includes a 4-meter diameter payload fairing and one solid rocket motor. Only three Atlas V’s have been launched in this configuration.
“This is an exciting time,” says Lauretta.
The spacecraft will reach Bennu in 2018. OSIRIS-REx will gather rocks and soil and bring at least a 60-gram (2.1-ounce) sample back to Earth in 2023 for study by researchers here with all the most sophisticated science instruments available.
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.
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.
OSIRIS-REx logo
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Artist's impression of a Near-Earth Asteroid passing by Earth. Credit: ESA
In February of 2014, NASA put out the call for submissions for the thirteenth mission of their Discovery Program. In keeping with the program’s goal of mounting low-cost, highly focused missions to explore the Solar System, the latest program is focused on missions that look beyond Mars to new research goals. On September 30th, 2015, five semifinalists were announced, which included proposals for sending probes back to Venus, to sending orbiters to study asteroids and Near-Earth Objects.
Among the proposed NEO missions is the Near Earth Object Camera, or NEOCam. Consisting of a space-based infrared telescope designed to survey the Solar System for potentially hazardous asteroids, the NEOCam would be responsible for discovering and characterizing ten times more near-Earth objects than all NEOs that have discovered to date.
If deployed, NEOCam will begin discovering approximately one million asteroids in the Main Belt and thousands of comets in the course of its 4 year mission. However, the primary scientific goal of NEOCam is to discover and characterize over two-thirds of the asteroids that are larger that 140 meters, since it is possible some of these might pose a threat to Earth someday.
Artist’s concept of the NEOCam spacecraft, a proposed mission for NASA’s Discovery program that would search for potentially hazardous near-Earth asteroids. Credit: NASA/JPL-Caltech
The technical term is Potentially Hazardous Objects (PHO), and it applies to near-Earth asteroids/comets that have an orbit that will allow them to make close approaches to Earth. And measuring more than 140 meters in diameter, they are of sufficient size that they could cause significant regional damage if they struck Earth.
In fact, a study conducted in 2010 through the Imperial College of London and Purdue University found that an asteroid measuring 50-meters across with a density of 2.6 grams per cubic centimeter and a speed of 12.7 kps could generate 2.9 Megatons of airburst energy once it passed through our atmosphere. To put that in perspective, that’s the equivalent of about nine W87 thermonuclear warheads!
By comparison, the meteor that appeared over the small Russian community of Chelyabinsk in 2013 measured only 20 meters across. Nevertheless, the explosive airbust caused by it entering our atmosphere generated only 500 kilotons of energy, creating a zone of destruction tens of kilometers wide and injuring 1,491 people. One can imagine without much effort how much worse it would have been had the explosion been six times as big!
What’s more, as of August 1st, 2015, NASA has listed a total of 1,605 potentially hazardous asteroids and 85 near-Earth comets. Among these, there are 154 PHAs believed to be larger than one kilometer in diameter. This represents a tenfold increase in discoveries since the end of the 1990s, which is due to several astronomical surveys being performed (as well as improvements in detection methods) over the past two and a half decades.
The NEOCam sensor (right) is the lynchpin for the proposed Near Earth Object Camera, or NEOCam, space mission (left). Credit: NASA/JPL-Caltech
As a result, monitoring and characterizing which of these objects is likely to pose a threat to Earth in the future has been a scientific priority in recent years. It is also why the U.S. Congress passed the “George E. Brown, Jr. Near-Earth Object Survey Act” in 2005. Also known as the “NASA Authorization Act of 2005”, this Act of Congress mandated that NASA identify 90% of all NEOs that could pose a threat to Earth.
If deployed, NEOCam will monitor NEOs from the Earth–Sun L1 Lagrange point, allowing it to look close to the Sun and see objects inside Earth’s orbit. To this, NEOCam will rely on a single scientific instrument: a 50 cm diameter telescope that operates at two heat-sensing infrared wavelengths, to detect the even the dark asteroids that are hardest to find.
By using two heat-sensitive infrared imaging channels, NEOCam can also make accurate measurements of NEO and gain valuable information about their sizes, composition, shapes, rotational states, and orbits. As Dr. Amy Mainzer, the Principal Investigator of the NEOCam mission, explained:
“Everyone wants to know about asteroids hitting the Earth; NEOCam is designed to tackle this issue. We expect that NEOCam will discover about ten times more asteroids than are currently known, plus millions of asteroids in the main belt between Mars and Jupiter. By conducting a comprehensive asteroid survey, NEOCam will address three needs: planetary defense, understanding the origins and evolution of our solar system, and finding new destinations for future exploration.”
Dr. Mainzer is no stranger to infrared imaging for the sake of space exploration. In addition to being the Principal Investigator on this mission and a member of the Jet Propulsion Laboratory, she is also the Deputy Project Scientist for the Wide-field Infrared Survey Explorer (WISE) and the Principal Investigator for the NEOWISE project to study minor planets.
She has also appeared many times on the History Channel series The Universe, the documentary featurette “Stellar Cartography: On Earth”, and serves as the science consultant and host for the live-action PBS Kids series Ready Jet Go!, which will be debuting in the winter of 2016. Under her direction, the NEOCam mission will also study the origin and ultimate fate of our solar system’s asteroids, and finding the most suitable NEO targets for future exploration by robots and humans.
Proposals for NEOCam have been submitted a total of three times to the NASA Discovery Program – in 2006, 2010, and 2015, respectively. In 2010, NEOCam was selected to receive technology development funding to design and test new detectors optimized for asteroid and comet detection and discovery. However, the mission was ultimately overruled in favor of the Mars InSight Lander, which is scheduled for launch in 2016.
As one of the semifinalists for Discovery Mission 13, the NEOCam mission has received $3 million for year-long studies to lay out detailed mission plans and reduce risks. In September of 2016, one or two finalist will be selected to receive the program’s budget of $450 million (minus the cost of a launch vehicle and mission operations), and will launch in 2020 at the earliest.
In related news, NASA has confirmed that the asteroid known as 86666 (2000 FL10) will be passing Earth tomorrow. No need to worry, though. At its closest approach, the asteroid will still be at a distance of 892,577 km (554,000 mi) from Earth. Still, every passing rock underlines the need for knowing more about NEOs and where they might be headed one day!
