A CHopper That Would Have Had an Amazing Ride

One of the two missions that was not selected under NASA’s Discovery Program was the Comet Hopper or “CHopper” mission to the comet Wirtanen. Image Credit: NASA/GSFC/University of Maryland

The name of one of the two missions not selected under NASA’s Discovery Program sounds like something off of the television series American Chopper – CHopper. However CHopper would have packed a bigger punch and would have traveled much farther than your average motorcycle.

The mission’s name stands for Comet Hopper, and would have seen a spacecraft travel along with a comet as the dirty snowball travels throughout the solar system. CHopper hit the chopping block along with the Titan Mare Explorer or TiME mission to Saturn’s moon, Titan.

CHopper would have traversed the surface of the comet Wirtanen by conducting a series of “hops” across the comet’s surface. This would have allowed researchers to document the changes that the comet undergoes as it approaches the Sun. Image Credit: Max-Planck-Institut f|r Aeronomie, Courtesy T. Credner, J. Jockers, T.Bonev

After a review in August 2012, NASA chose InSight, a mission that will use the proven Phoenix Mars Lander’s design to study the composition of the Red Planet’s interior.

Jessica Sunshine was the proposed mission’s principal investigator. Sunshine is with the University of Maryland and would have coordinated with Lockheed-Martin to build and NASA’s Goddard Space Flight Center to manage the spacecraft.

CHopper was one of three finalists under NASA’s Discovery Program, an effort to see smaller, lower-cost missions launched to destinations throughout the solar system. Each finalist received $3 million to develop a study as to what science each mission would accomplish.

The selection of InSight over the other two applicants caused an outcry from the space community. Many felt that too much attention and funding was being paid to Mars and not enough to the outer solar system and near Earth objects or “NEOs”.

Wirtanen was just such a NEO. CHopper would have had three main science objectives over the course of the seven years that the mission was planned for. During this period the spacecraft would have mapped the different terrain and materials that comprised the surface of the comet.

It would have also studied the gas emissions that jet out of the comet as it gets closer to the Sun. These jets emit from the comet’s coma, the halo of vapor that surrounds the comet’s nucleus. This could have provided more accurate data as to how these processes work as the comet interacts with the Sun.

Image Credit: UMD

CHopper would have approached, landed on and then “hopped” to different points on Wirtanen. Rendezvous would have occurred about 415 million miles away from Earth, with the final landing occurring approximately 140 million miles away from our home world. As Wirtanen traveled nearer to the Sun, CHopper would have been able to document the changes that the comet undergoes.

“We would extensively explore the surface of a comet, this is something that has never been done before,” said Joe Nuth, Comet Hopper project scientist at NASA Goddard. “We know that there are volatiles (molecules that easily evaporate at normal temperatures) inside a comet. We would go to places that are relatively flat and are likely hiding volatiles. Comet Hopper could be called a reconnaissance mission for an upcoming Comet Nucleus Sample Return mission, which has been deemed a high priority development effort by the Decadal Survey.”


  1. Is that right? A rendezvous 415 miles away from the sun? That seems a little too close for comfort.

  2. 415 miles is absurd. Please correct the obvious numerical errors in this article. Longtime fan of this site. Thanks.

    • Apparently it takes a couple of minutes for comments to post. Thanks for the correction.

One Ping

  1. Pingback:

A Mission Ahead of its TiME?

Waterworlds: The Search For Life in the Outer Solar System