Frequently Asked Questions - Learn More
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The OSIRIS-REx mission is an Asteroid Sample Return Mission
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OSIRIS-REx is an acronym that describes the work of the mission:
| Origins |
The mission will return a pristine sample to Earth to reveal the origins of volatiles and organics that may be the seeds of life on Earth. |
| Spectral Interpretation |
Instruments will map the properties of asteroid and analyze the sample to compare with telescopic studies of B-type carbonaceous asteroids and lab analyses of meteorites to provide ground-truth for these observations. |
| Resource Identification |
The mission will identify carbonaceous asteroid resources that we might use in human exploration. |
| Security |
Measurements will quantify the Yarkovsky Effect on this potentially hazardous asteroid, thus providing a tool to aid in securing the Earth from future asteroid impacts. |
| Regolith Explorer |
The mission will explore the regolith at the sampling site in situ at sub-centimeter scales. |
The ancient Egyptians believed that Osiris was the god of the dead and the afterlife with connections to the harvest and fertility - connections to life.
The OSIRIS-REx mission will thoroughly characterize near-Earth asteroid (101955) Bennu. Asteroids are the direct remnants of the original building blocks of the terrestrial planets. Knowledge of their nature is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System.
The mission’s scientific objectives are:
- Return and analyze a sample of pristine carbonaceous regolith;
- Map global properties, chemistry, and mineralogy of the asteroid;
- Investigate texture, morphology, volatile chemistry, and spectral properties of the regolith;
- Measure the Yarkovsky effect; and
- Provide direct comparison to telescope-based data of the entire asteroid population.
The criteria for choosing asteroid (101955) Bennu
(101955) Bennu is the most exciting, accessible volatile and organic-rich remnant from the early Solar System, as well as the most potentially hazardous asteroid known to humanity.
Bodies from the outer main asteroid belt are believed to be the dominant source of primordial terrestrial organics and possibly water. In the chaotic early Solar System, many collided with the young planets bringing organics and possibly water to them. Water and carbon are the building blocks of life on Earth.
Bennu has abundant regolith (click here to find out what 'regolith' is), comprised of fine gravel (4-8 mm) which is ideal for collecting a sizable sample. With this sample, scientists will be able to analyze the asteroid’s composition, mineralogy and geology to learn more about it and other B-type asteroids.
Every six years, Bennu’s orbit takes it near the Earth - to within 448,794 km (278,867 mi, 0.003 astronomical units). Calculation of its future orbits indicate that Bennu has one of the highest impact probabilities in the next few centuries of any known asteroid. Understanding the orbit, effects on orbit and composition will help scientists better determine the orbit of the asteroid to provide more conclusive data on how and when it might impact Earth. These data will be available to all. With time, policymakers will be able to decide what (if any) steps should be taken to mitigate the risk of impact. To find the current position of Bennu, go to http://neo.jpl.nasa.gov/orbits/. For more on near-Earth asteroids and impact hazards, go to http://neo.jpl.nasa.gov/.
Mapping the characteristics of the asteroid with instruments during rendezvous (2019-2020) the OSIRIS-REx spacecraft will not only determine the optimum sampling site but also obtain important data about composition and behavior. Scientists will determine topography, composition and orbital characteristics.
Bennu is a B-type (sub-group of C-type) asteroid. B-type are carbonaceous, rich in volatiles and possible representatives of asteroids which brought seeds of life to Earth early in its history.
Telescopic observations of Bennu have allowed scientists to refine the orbit of the asteroid to a great extent, but the rendezvous with the asteroid will allow more precise determination of the characteristics, which affect the orbit. This mission will measure the Yarkovsky effect (click here to read about the Yarkovsky effect) to understand Bennu’s orbit and mechanics that affect other Near Earth Object orbits (click here to read about what a Near Earth Object is).
(1010955) Bennu (click here to read about how asteroids are named) is a near-Earth object (click here to read about what a Near-Earth Object is). It completes an orbit of the Sun every 436.604 days (1.2 years). This orbit takes it close to the Earth every six years. Although the orbit is reasonably well known, scientists continue to refine it. It is critical to know the orbit of Bennu because recent calculations produce a 1 in 1800 chance of impact with Earth in the year 2182. Part of the OSIRIS-REx mission is to refine understanding of effects on this orbit and produce information to refine the calculations of the orbit and its intersection with Earth’s. Will Earth and Bennu be in the same place at the same time and when?
Telescopic observations have revealed some basic properties of Bennu. They indicate that Bennu is very dark. Scientists have classified it as a B-type asteroid. B-type is a rare subgroup of the dark, carbonaceous C-type asteroids. These asteroids are considered “primitive” having undergone little processing from their time of formation.
Click here to see where Bennu is.
The orbital period of Bennu is 436.6 days (1.2 years).
The mean orbital speed of Bennu is 27.8 kilometers/second (17.3 miles/second).
What we know of asteroids, we have learned through telescopic observations and laboratory analysis of meteorites, the fragments of asteroids that travel through the Earth’s atmosphere, land and are recovered. Telescopic observations can tell scientists a lot – even about these very dim objects: Scientists analyze data they collect to construct models of mass, density, rotation and composition. From meteorite analyses, researchers can determine composition, density, mass and create models of the parent bodies and their formation and history.
Telescopic observations, lab analyses and models will be concretely linked by bringing a physical sample of an asteroid back to the lab to study. From such study, scientists will be able to ground-truth – to confirm the facts with an actual field check! Were the assumptions and conclusions used to create the models correct or do they need to be revised?
The OSIRIS-REx mission is a 14-year undertaking from selection in May 2011 through 2025 sample analyses. Sample analysis will continue for decades beyond the mission proper – if the Apollo samples are any indication – with scientists not yet born making use of techniques we have yet to invent.
The OSIRIS-REx mission schedule is based on the Design Reference Mission (see image below), a model for how the mission will proceed. This schedule shows the major mission milestones during all phases.
Design Reference Mission Timeline: click on the timeline to view in higher resolution.
1,349,382,617 km (838,467,486 miles) round trip relative to the Earth.
654,389,243 km (406,618,624 miles) for the trip out.
512,465,122 km (318,431,064 miles) for the trip back
Lockheed Martin will build the spacecraft and use heritage from the Stardust mission, NASA’s comet sample return mission. Various partners will build instruments for the mission.
Spacecraft Stats
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Instruments
A suite of instruments flies on board the spacecraft to provide information necessary to carry out the science and select the optimal sampling site. Instruments operate at different wavelengths with overlap in capabilities.
OSIRIS-REx Camera Suite (OCAMS)
This suite consists of Poly Cam, MapCam, and SamCam, which provide long-range acquisition of Bennu and imaging of its surface down to millimeter ranges, along with global mapping, sample-site characterization, and sample acquisition documentation. The University of Arizona is building OCAMs.
OSIRIS-REx Laser Altimeter (OLA)
Provides ranging data in support of radio science; global topographic mapping; and local topographic maps of candidate sample sites. The Canadian Space Agency is building OLA.
OSIRIS-REx Visible and IR Spectrometer (OVIRS)
Provides mineral and organic spectral maps and local spectral information of candidate sample sites from 0.4 - 5 microns. NASA Goddard Space Flight Center is building OVIRS.
OSIRIS-REx Thermal Emission Spectrometer (OTES)
Provides mineral and thermal emission spectral maps and local spectral information of candidate sample sites from 4 - 50 microns. Arizona State University is building OTES.
REgolith X-ray Imaging Spectrometer (REXIS)
MIT-Harvard student collaboration experiment’s coded aperture soft x-ray (0.3-7.5 keV) telescope provides global mapping of elemental abundances and documentation of sampling site. MIT and Harvard are building REXIS.
For more information see the Spacecraft and Payload pages.
NASA requires missions to allocate 1-2% of mission funds to education and public outreach. The OSIRIS-REx E/PO program is national in scope. Working with partners around the country and partnering with other NASA missions and E/PO programs, the OSIRIS-REx E/PO program will produce content and activities for formal (K-12) and informal (public) venues. The OSIRIS-REx E/PO program also provides the opportunity for high school, undergraduates and graduate students to work on the mission.
- General Fact Sheet
- Technical Fact Sheet
- Website with links to additional resources
- Facebook page
- Twitter account
The OSIRIS-REx E/PO program is developing additional materials and programs. Look for posters, build-the-spacecraft template, mascot creation, and citizen science project roll-outs over the next year.
The E/PO group has various ways for people to become involved. The OSIRIS-REx E/PO program has a variety of volunteer jobs ranging from simple logistical aid, to helping develop materials and activities, to presenting programs with opportunities increasing as we ramp up after launch in 2016.
- Logistical Support for E/PO Activities
- Internet Support for E/PO Activities
- Database Support for E/PO Activities
- Preparation of E/PO Activities and Materials
- Representing the OSIRIS-REx mission at Local Events
- Administrative and Office Help
- Program and Material Development
A Near-Earth Object is a comet or asteroid orbiting the Sun in the neighborhood of the Earth. Most asteroids reside in the asteroid belt between Mars and Jupiter. Over 500,000 main belt asteroids are known. Over 8,000 near-Earth objects have been found. Comets reside in the outer solar system but recent studies indicate that there is a spectrum of objects. An object becomes an NEO because the gravitational attraction of planets (primarily the very large Jupiter) and other objects have nudged it into an orbit that brings it into Earth’s neighborhood.
The OSIRIS-REx mission targets asteroid (101955) Bennu (formerly 1999 RQ36). When observers discover small objects in the solar system, the Minor Planet Center gives them formal names.
* The number in the month discovered is not a straightforward count. R indicates the first half of September. Q indicates the 16th object discovered in the first half of September but….the 36 indicates that this is the 37th time (count starts with zero) that Q was used making this asteroid the 916th object discovered in the first half of September 1999.
Regolith is a blanket of loose materials covering rock. It can be soil, gravel, dust, broken rocks. The word originates from the Greek words rhegos “blanket” and lithos “rock.”
In 1902, Ivan Yarkovsky suggested that the daily heating of an object rotating in space could exert a small force on the object. We know how the temperature on Earth gets warmer and warmer as the Sun rises, hitting a maximum somewhere in the early afternoon. The same thing occurs on an asteroid. When the heated surface of Bennu points its hot afternoon side in the direction of its motion around the Sun - the escaping radiation acts like a tiny rocket thrust, slowing it down and sending it closer to the inner solar system. Although tiny, a little push day after day, year after year for hundreds of years can change an asteroid’s orbit significantly – transforming an Earth impactor into a close fly-by or a clean miss.
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Scientists study objects from stars to small grains of rock using techniques that look at objects at different wavelengths. Quantity of elements and molecules can be mapped for different wavelengths, and scientists refer to the measurements at different wavelengths as spectral characteristics. Looking at an object spectrum, scientists can determine the composition – how much of various elements and molecules, such as iron, water – are in objects (or on their surfaces). Telescopic observations of asteroids and lab analyses of meteorites measure elements and produce spectra. The image to the right shows comparison between spectra from different asteroid and meteorite types. |
A comparison of reflectance spectra of asteroid and meteorite types that may be interpreted as associating some such types. After: "Classifying and Modeling NEO Material Properties and Interactions", John L. Remo, in Hazards due to Comets & Asteroids (1994, T. Gehrels, ed., The University of Arizona Press, 1300 p.), p. 561. |
The OSIRIS-REx mission propulsion system uses hydrazine propellant as used on the Stardust mission. For more information about hydrazine propellent use, an article on Wikipedia provides the basics. Lockheed Martin is building the spacecraft.
At present scientists calculate high potential for Bennu to impact Earth in the late 22nd century. After the OSIRIS-REx spacecraft encounter, scientists will recalculate the trajectory of the asteroid in order to assess the actual long-term effect of touch-and-go sampling (TAGSAM) in 2020. Depending on the location of the TAGSAM on Bennu, the trajectory may be altered by the late 22nd century. Keep in mind that the TAGSAM is a 5-second, very light touch compared to the Yarkovsky effect, which although small each day, operates daily over centuries.
Bennu's orbit brings it relatively close to Earth every six years. The closest approach distance varies for each close-approach. In September 2011, Bennu was 26,478,823 km (or 16,453,178 mi or 0.177 AU) from Earth. It won't be this close again until 2037 when it will be 14,810,189 km (or 9,202,625 mi or 0.099 AU) from Earth. In 2060, Bennu will pass even closer at 747,989 km (464,779 mi or 0.005 AU) of Earth - about two times the distance of the Moon from the Earth.
NASA has stringent protocols to ensure that its missions do not transport threatening materials to Earth. An international treaty governs NASA’s activities related to planetary protection. NASA’s OSIRIS-REx mission follows these protocols and all related requirements to prevent contamination of the Earth and other Solar System bodies. These protocols include requirements for both the spacecraft and for any returned samples. For more information see http://planetaryprotection.nasa.gov/.
Many tons of material from asteroids, comets and beyond land on Earth every day. As they pass through the atmosphere, they are called meteors. Although meteors do heat up as they pass through the Earth’s atmosphere, their interiors remain cold even while the outside is hot. Consequently, meteorite interiors are not sterilized as they travel through Earth’s atmosphere.
Exposure to radiation and heat in interplanetary space can sterilize materials. The OSIRIS-REx mission target asteroid, (101955) Bennu, is very old and has had many close approaches to Earth. Scientists believe that these encounters have rearranged its structure, moving materials from its interior to its surface and back. Because Bennu is so dark the surface gets quite warm (up to 170° F). As the asteroid moves through space, its surface has been subjected to enough heat and solar and galactic radiation to kill many Earth organisms. So even if conditions were right for life to originate on Bennu (which is highly unlikely), it would have been irradiated, cooked, and have few places to hide.
The E/PO activities roll-out over the course of the mission with most activities starting after launch in 2016. Prior to launch, the OSIRIS-REx mission will start the Target Asteroids! citizen science program, the Name that Asteroid! contest with The Planetary Society in addition to participating in local events and partner activities.
E/PO timeline (click to view in higher resolution):
For those who would like to have more detailed specifications of the spacecraft and mission management, download the technical fact sheet!
