text: NASA Wants To Study Comets, Earthbound Asteroids Using Quarter-Sized Thermometer
  10/31/17 AT 3:10 AM
  NASA is working on two efforts to develop compact technologies that could help understand comets better and maybe even deflect asteroids on a collision course with Earth. These devices are highly sensitive thermometers, with their cross-section just slightly larger than the diameter of a quarter coin.
  One of the devices being developed is called Comet CAMera, or ComCAM. Built by Canada's National Optics Institute, it was partially designed by NASA's Goddard Space Flight Center scientist Shahid Aslam. ComCAM is a microbolometer camera, or a very sensitive thermal sensor which is capable of measuring infrared radiation.
  "When radiation strikes an absorptive element, the element heats and experiences a change in the electrical resistance, which is proportional to and can be used to derive the temperature. These measurements provide insights into the physical properties of the object being studied. Scientists often use them to study very distant stars and galaxies in the universe," NASA explained its working in a statement Monday.
  Microbolometers usually need super cooling to operate, for which they have to be placed in canisters, but ComCAM does not have such rigorous temperature requirements and therefore doesn't need a canister either, making it lighter and smaller than traditional microbolometers.
  Aslam is part of a team led by Tilak Hewagama, and the team wants to fly ComCAM — along with a traditional visible-light camera — on a potential CubeSat mission which has been chosen for further study by the space agency's Planetary Science Deep Space SmallSat Studies. The CubeSat mission is called Primitive Object Volatile Explorer, and the tiny PrOVE spacecraft would be parked in a deep-space orbit.
  "A CubeSat deployed from a parked orbit can produce high-quality science by traveling to any comet that passes through the accessible range, rather than a dedicated mission that cannot be prepared in time to investigate a new, pristine comet that comes into view," Hewagama explained in the statement.
  His team is currently working on ascertaining the long-term stable parking orbits for ComCAM that will act as "waypoints," the transfer trajectories to these waypoints and the intercept trajectories, propulsion requirement to get to known comets, longevity of the spacecraft, and so on.
  "Our study obviously will bear out important questions regarding PrOVE's trajectory and orbit, among other technical questions, but this is a mission that could be deployed quickly. PrOVE represents an exceptional opportunity to advance the science of comets and other primitive bodies by studying them at close range. It would advance NASA science goals with data that only can be obtained with a spacecraft," Hewagama said.
  The other microbolometer-based technology under development is part of NASA's DART mission, short for Double Asteroid Redirection Test. This sensor could be used for planetary defence, by helping another spacecraft with the precise guidance measurements needed to deflect or destroy a potential asteroid that was on a collision course with Earth.
  Goddard technologists Josh Lyhoft and Melak Zebenay are considering various sensor systems to meet that objective, which includes imaging and characterizing asteroids.
  "Microbolometers can perform the task. We believe they're sensitive enough for a terminal-intercept mission," Lyzhoft said in the statement.
  DART is led by scientists from John Hopkins Applied Physics Laboratory and its aim is to use a kinetic impactor to change the path of an asteroid. A test of the mission is planned for 2024, with the smaller of the two asteroids in the Didymos system.