1. Comet Radar Explorer (CoRE)
David Geng, Reece Elling, and Matthew Lees

2. Comet Background
Comets are believed to be composed of leftover material from the beginning of our solar system around 4.6 Ga
Composed primarily of ice (both water and frozen gases such as ammonia or methane) and dust that didn’t get incorporated into planetary formation
Formed of a solid, frozen nucleus often only a few kilometers in diameter

3. Comet Background
Comets have elongated elliptical orbits where they only come close to Earth and the Sun for a short part of their orbit
As the comet reaches its perihelion, the sun warms it up, causing the ices to change to gases forming a coma that can extend hundreds of thousands of kilometers
Sunlight and solar wind blow the coma dust and gas so that a comet's tail is always pointing away from the sun

4. Comet Background
Often classified by the length of their orbital periods:
Long-Period (200 to 100,000’s of years) that likely originate from the Oort Cloud
Short-Period (< 200 years) that likely originate from the Kuiper Belt outside of Neptune’s orbit (ex. Halley’s)
Comets that orbit near a major planet are typically called its “family”
For example, Jupiter-family comets (JFCs) all have short orbital periods less than 20 years
Over 500 JFCs have been identified, and these are good targets for study due to the short orbital periods

5. Comet Background
Often classified by the length of their orbital periods:
Long-Period (200 to 100,000’s of years) that likely originate from the Oort Cloud
Short-Period (< 200 years) that likely originate from the Kuiper Belt outside of Neptune’s orbit (ex. Halley’s)
Comets that orbit near a major planet are typically called its “family”
For example, Jupiter-family comets (JFCs) all have short orbital periods less than 20 years
Over 500 JFCs have been identified, and these are good targets for study due to the short orbital periods

6. Comet 10P/Tempel 2 Target of the CoRE mission
Discovered by Willhelm Tempel in 1873 and observed extensively since, making it one of the best studied members of Jupiter’s family of short-period comets
One of the largest known comet nuclei, roughly 16x8x8 km
Very active, especially given its size

7. Comet 10P/Tempel 2 Target of the CoRE mission
Discovered by Willhelm Tempel in 1873 and observed extensively since, making it one of the best studied members of Jupiter’s family of short-period comets
One of the largest known comet nuclei, roughly 16x8x8 km
Very active, especially given its size

8. Key Scientific Issues Or More Simply
Origins of cometary nuclei
How do primitive bodies accrete?
Composition throughout interior
Physical and geological evolution
Mechanisms driving their spectacular activity
Or More Simply
How did it form?
What are we actually seeing?
Is it mostly ice?
How does it work?

9. Why is this important?
In-depth studies of comets can likely yield important clues about the formation of our solar system
May have been the primary carriers of water and organic compounds - the building blocks of life - to early Earth

10. Why is this important?
Still many unanswered questions about the geology of comets:
Do global layers that we see on the surface persist through to the interior?
Are smooth regions indications of landslides or could they be cryovolcanic?
Are pits impact craters of sublimation pits rooted in the interior?
Comet C-G

11. Timeline Depart July 2021 FlyBy Earth in July 2023
Arrive in November 2026
On Arrival
Approach and flyby Tempel 2
Optical Mapping Orbit
Radar Mapping Orbit - primary mission phase

12. Mission Approach and Flybys Assess the active regions
Obtain the required tracking and imaging data for orbit.
Optical Mapping Orbit (OMO)
A sequence of ~9 to 11 am/pm polar orbits
For multi-wavelength visible imaging and photometry
Measurements of temperature and thermal inertia
Radar Mapping Orbit (RMO)
Radar “Cat Scan” of the nucleus
By looking at the visible and infrared parts of the spectrum, THEMIS is determining the distribution of minerals on the surface of Mars and helping scientists understand how the mineralogy of the planet relates to the landforms.

13. Instruments on CORE Science and Navigation Camera (SNC)
Designed the same as DLR Framing Camera on DAWN mission
Will obtain color images and photometric observations globally to a pixel scale <3m
Helpful for understanding geology and for constructing the comet nucleus shape model and optical navigation
Show is a three-dimensional color image of one of Vesta’s smaller craters made using this camera.

14. Instruments on CORE Comet Infrared Imager (CIRI)
High-heritage microbolometer imager sensitive to the K temperature range expected at the nucleus
Will obtain repeated daytime/nighttime images that are co-aligned with the multi-wavelength visible images
is a high-heritage microbolometer (7-25 μm) imager sensitive
to the K temperature range expected at the nucleus (modeled below). It will be
built at ASU by the team that delivered THEMIS for Mars Odyssey. CIRI will obtain repeated
daytime/nighttime images, that are co-aligned with the multi-wavelength visible images.

15. Instruments on CORE SHARAD Heritage Radar SHAllow subsurface RADar
Used for reflection radar imaging hardware and data processing
Will give us a “Cat Scan” of the nucleus using coherent reflection sounding measurements
On board the Mars Reconnaissance Orbiter (MRO)
Much simpler to use on a comet than on a planet
A reflection radar deployed in orbit about a comet will enjoy significant simplifying benefits compared to using the same instrument for Mars or lunar radar science: (1) The proximity of operations leads to a much higher signal to noise, as much as +30 dB. (2) The lack of an ionosphere simplifies data modeling and analysis. (3) The body is globally illuminated during every data acquisition, minimizing ambiguity or 'clutter' and allowing for tomographic reconstruction.

16. SHARAD processed images from MRO
MRO = Mars Reconnaissance Orbiter
Take the SHARAD observations from collections of 2-D profiles to geometrically corrected 3-D volumes for each polar region.
Crucial to focused processing of orbital radar data is an accu-
rate representation of the spacecraft velocity and the local surface
slope. Horizontal reflectors directly below the spacecraft typically
yield the strongest surface and subsurface returns.

17. How this affects life on Earth?
Helps us understand where life potentially came from (seeding)
Simple life forms could have started on comets
Bodies it has made contact with could have pre- seeded it
Transported life to earth when the comet landed
Amino Acids found on Comet Wild 2

18. How this affects life on Earth?
Structure of comet can help us learn where volatile substances came from
Studying core of Tempel 2 can potentially find new volatile substances hidden inside

19. How this affects life on Earth?
Learning more about the physical attributes of a comet can allow us to better estimate the amount of force released during collisions
Could potentially help us negate hazardous objects

20. How this affects life on Earth?
Tells us about elements at the beginning of solar system
Collects elements from outer solar system and brings them closer to us
Lets us examine clues from the outer system