page_title: Discovery Program
section_title: Proposals and concepts
hierarchical_section_title: Discovery Program / Proposals and concepts
caption_attribution_description: English: Possible configuration of the spacecraft - "South Pole-Aitken Basin Sample Return". This mission would use robotic technology to gather samples from the Moon's South Pole-Aitken Basin and return them to Earth for study. The Aitken Basin, a massive impact crater on the Moon's far side, may provide access to samples of the lunar mantle, which could give scientists insight into the period of heavy bombardment early in our solar system's history.
context_page_description: The Discovery Program is a series of Solar System exploration missions funded by the US National Aeronautics and Space Administration through its Planetary Missions Program Office. Each mission has a cost cap, at a lower level than a mission from NASA's New Frontiers or Flagship Programs. As a result, Discovery missions tend to be more focused on a specific scientific goal.
  The Discovery Program was founded in 1990 to implement then-NASA Administrator Daniel S. Goldin's policy of "faster, better, cheaper" planetary science missions. Existing NASA programs had specified mission targets and objectives in advance, then sought bidders to construct and operate them. In contrast, Discovery missions are solicited through a call for proposals on any science topic, and assessed through peer review. Selected missions are led by a scientist called the Principal Investigator and may include contributions from industry, universities, or government laboratories.
  The Discovery Program also includes Missions of Opportunity, which fund US participation in spacecraft operated by other space agencies. It can also be used to re-purpose an existing NASA spacecraft for a new mission.
context_section_description: However often the funding comes in, there is a selection process with perhaps two dozen concepts. These sometimes get further matured and re-proposed in another selection or program. An example of this is Suess-Urey Mission, which was passed over in favor of the successful Stardust mission, but was eventually flown as Genesis, while a more extensive mission similar to INSIDE was flown as Juno in the New Frontiers program.  Some of these concepts went on to become actual missions, or similar concepts were eventually realized in another mission class. This list is a mix of previous and current proposals.
  Additional examples of Discovery-class mission proposals include:
  Whipple, space-observatory to detect objects in the Oort cloud by transit method.
  Io Volcano Observer
  Comet Hopper (CHopper)
  Titan Mare Explorer (TiME)
  Suess-Urey, similar to the later Genesis mission.
  Hermes, a Mercury orbiter. (compare to MESSENGER Mercury orbiter)
  INSIDE Jupiter, an orbiter that would map Jupiter's magnetic and gravity fields in an effort to study the giant planet's interior structure.  The concept was further matured and implemented as Juno in the New Frontiers program.
  The Dust Telescope is a space observatory that would measure various properties of incoming cosmic dust. The dust telescope would combine a trajectory sensor and a mass spectrometer, to allow the elemental and even isotopic composition to be analyzed.
  OSIRIS (Origins Spectral Interpretation, Resource Identification and Security) was an asteroid observation and sample return mission concept selected in 2006 for further concept studies.  It was further matured and launched September 8, 2016 as OSIRIS-REx in the New Frontiers Program.
  Small Body Grand Tour, an asteroid rendezvous mission. This 1993 concept reviews possible targets for what became NEAR— 4660 Nereus and 2019 Van Albada. Other targets considered for an extended mission included Encke's comet (2P), 433 Eros, 1036 Ganymed, 4 Vesta, and 4015 Wilson–Harrington (1979 VA). (NEAR did visit 433 Eros and Dawn visited 4 Vesta)
  Comet Coma Rendezvous Sample Return, a spacecraft designed to rendezvous with a comet, make extended observations within the cometary coma (but not land on the comet), gently collect multiple coma samples, and return them to Earth for study. (See also Stardust (spacecraft))
  Micro Exo Explorer would use a new form of micro-electric propulsion, called 'Micro Electro-fluidic-spray Propulsion' to travel to a near Earth object and gather important data.
caption: Possible configuration of a lunar sample return spacecraft
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