The DS defined GEO-CAPE as a Tier 2 mission that could be implemented with mature instrumentation
that had significant space heritage in LEO. The implied mission implementation was multiple instruments
on one large spacecraft. Although this implementation approach for GEO-CAPE was studied and found to be
technically feasible, the total cost of a single large mission appears to be prohibitively expensive.
Consequently, alternative mission implementation concepts [PDF]
that would launch individual GEO-CAPE instruments on separate spacecraft are being studied to provide flexibility while reducing cost and risk.

Ongoing studies continue to refine GEO-CAPE measurement and instrument requirements.
Specific instruments for GEO-CAPE have not yet been selected. A conceptual planning payload based on the notional instruments
described in the Decadal Survey is being used to advance the mission design studies.

+ View the GEO-CAPE Planning Payload Document [PDF]

At this preliminary stage, several instrument concepts are being studied to ensure that a range of potential instruments
can meet GEO-CAPE atmosphere and ocean requirements.
These instrument concepts are suitable for implementation either together on a single dedicated satellite or individually
as secondary payloads on separate spacecraft.

Instrumentation hosted as secondary payloads on commercial satellite
missions offers several benefits that can reduce mission implementation cost and risk.

• Instrumentation as hosted payloads on commercial satellite missions
  provides flexibility and opportunities to use established commercial
  infrastructure to carry out the GEO-CAPE mission sooner at an affordable cost.
• Compared to a single large observatory, a phased mission implementation of distributed
  payloads on separate spacecraft would enable science/applications sooner, provide a
  more flexible cost profile, and lower mission exposure to risks.
• A risk reduction mission conducted mid-decade could demonstrate the benefits
  of the hosted payload mission model and inform decisions for the full GEO-CAPE implementation strategy.

The goal of these alternative concepts is to allow all of the scientific objectives of GEO-CAPE
to be accomplished sooner than otherwise possible. A notional timeline shows how individual
components of GEO-CAPE could be aligned with complementary US and international missions.