Comet Hopper (CHopper) was a proposed lander to NASA's Discovery Program that, had it been selected, would have orbited and landed multiple times on Comet Wirtanen as it approached the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. The proposed mission was led by Jessica Sunshine of the UMD, working with

Lockheed Martin The Lockheed Martin Corporation is an American aerospace, arms, defense, information security, and technology corporation with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It ...

to build the

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

and the NASA Goddard Spaceflight Center to manage the mission.

History

The Comet Hopper mission was one of three Discovery Program finalists that received million in May 2011 to develop a detailed concept study. The other two missions were

InSight Insight is the understanding of a specific cause and effect within a particular context. The term insight can have several related meanings: *a piece of information *the act or result of understanding the inner nature of things or of seeing intu ...

and

Titan Mare Explorer Titan Mare Explorer (TiME) is a proposed design for a lander for Saturn's moon Titan. TiME is a relatively low-cost, outer-planet mission designed to measure the organic constituents on Titan and would have performed the first nautical exploratio ...

. After a review in August 2012, NASA selected the InSight mission.

Scientific goals

The CHopper mission had three primary science goals for the 7.3 years of its lifetime. At roughly 4.5 AU the spacecraft would have rendezvoused with Comet Wirtanen to map the spatial heterogeneity of surface solids as well as gas and dust emissions from the

coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...

- the nebulous envelope around the

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucle ...

of a

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...

. The remote mapping would also allow for any nucleus structure, geologic processes, and coma mechanisms to be determined. After arriving at Comet Wirtanen, the spacecraft would have approached and landed, then subsequently hopped to other locations on the comet. As the comet approached the sun, the spacecraft would land and hop multiple times to record surface changes as the comet became more active. The final landing would occur at 1.5 AU.

References

External links

;Press Releases :
NASA Goddard Managed Comet Hopper Mission Selected for Further Study
:
Comet Hopper, a UMD/NASA Goddard Proposal, Moves to 'Final Round' in NASA Selection Process
;News Articles :
Maryland scientists vie for NASA missions
{{Comet spacecraft Cancelled spacecraft Missions to comets Advanced Stirling radioisotope generator Discovery program proposals Hopping spacecraft

History

Scientific goals

See also

References

External links