Could a different NASA-ESA barter arrangement be made that includes the following characteristics?
- includes ESA in NASA's exploration plans
- doesn't upset an applecart that has been designed for many years
- adds value to NASA's plans
- involves distinct elements to reduce managerial and political complexity
- uses ESA's strengths
- does not damage U.S. interests, such as subsidizing European competition with U.S. commercial space
- involves work that ESA would want to do (fitting their long-term goals, using their industry, etc)
If we are planning to return to the Moon, robotic precursor missions could assess lunar resources, do ISRU experiments, and so on. Missions might be similar to the roving Lunar Polar Volatiles Explorer, a static lander with experiments and a Mars Pathfinder sized lunar rover to assess resources as considered by NASA's robotic precursor team, or the Lunar South Pole-Aitken Basin Sample Return mission (which is also a high priority on NASA's Planetary Science side).
If we are planning to go to NEOs during some of the steps on the Flexible Path to Mars, robotic precursor missions could broadly search for suitable candidate NEOs using instruments like NEOCAM, do NEO flyby missions to assess basic characteristics of multiple NEOs, or go to a particularly interesting NEO candidate to do detailed resource investigations, ISRU experiments, and search for hazards (such as small satellite asteroids).
Some robotic precursor missions might involve NASA-ESA collaboration in a single spacecraft just as suggested with the Orion barter deal with an ESA SM. Planetary Science has a lot of successful experience with this sort of collaboration, where instruments or even entire landers are hosted on a spacecraft from another country. (This is not to suggest that the Orion barter arrangement would not work or international collaboration hasn't happened on non-Planetary missions - e.g. ISS and Orbital's Antares/Cygnus).
Similarly, exploration technology development is getting limited funding. The earlier Administration proposal to demonstrate highly capable solar electric propulsion, propellant depots, AR&D tugs, inflatable modules, closed-loop life support, and aerocapture during the start of a series of well-funded exploration technology demonstration missions while also funding technology development in numerous areas like ISRU, landing, telerobotics, fission power systems, and even more capable electric propulsion have been scaled back almost beyond recognition. Could ESA contribute to implementing some of these or similar exploration technology demonstration missions in a way that would give NASA the data that it needs, and perhaps even give NASA a ride to demonstrate some of the exploration technologies that NASA can afford to develop even now? For example, could ESA do an aerocapture demonstration mission at Mars, or even at Earth, giving NASA access to the data? Could ESA collaborate with NASA and U.S. commercial space to demonstrate an inflatable habitat module where ESA provides some of the internal and external components of the system, or would such an arrangement have similar potential disadvantages to the Orion/ESA SM barter? The long-term interest for ESA might be in participation by ESA or European industry when such modules are used as habitats in exploration missions, or when they are used commercial space habitats.
The point I'm trying to make is that there are a number of important exploration jobs that currently aren't being done that could be more productive subjects of NASA-ESA barter arrangements than the Orion SM. Suggestions on what those might be are welcome.