TABLE E.1 Technology Area Breakdown Structure for TA02, In-Space Propulsion Systems

NASA Draft Roadmap (Revision 10) Steering Committee-Recommended Changes
TA02 In-Space Propulsion Technologies Four technologies have been deleted.

2.1.   Chemical Propulsion


2.1.1.    Liquid Storable


2.1.2.    Liquid Cryogenic


2.1.3.    Gels


2.1.4.    Solid


2.1.5.    Hybrid


2.1.6.    Cold Gas/Warm Gas


2.1.7.    Micro-Propulsion


2.2.     Non-Chemical Propulsion


2.2.1.    Electric Propulsion


2.2.2.    Solar Sail Propulsion


2.2.3.    Thermal Propulsion


2.2.4.    Tether Propulsion


2.3.     Advanced (TRL <3) Propulsion Technologies


2.3.1.    Beamed Energy Propulsion


2.3.2.    Electric Sail Propulsion


2.3.3.    Fusion Propulsion


2.3.4.    High Energy Density Materials


2.3.5.    Antimatter Propulsion


2.3.6.    Advanced Fission


2.3.7.    Breakthrough Propulsion


2.4.     Supporting Technologies


2.4.1.    Engine Health Monitoring & Safety

Delete: 2.4.1. Engine Health Monitoring & Safety

2.4.2.    Propellant Storage & Transfer


2.4.3.    Materials & Manufacturing Technologies

Delete: 2.4.3. Materials & Manufacturing Technologies

2.4.4.    Heat Rejection

Delete: 2.4.4. Heat Rejection

2.4.5.    Power

Delete: 2.4.5. Power

The scope of each of these technologies actually falls outside the scope of TA02, and NASA’s draft roadmap for TA02 does not suggest that any of them should be developed as part of TA02. Except for item 2.4.2, this section of the roadmap is used to highlight level 1 or level 2 topics in other roadmaps that are important to the TA02 roadmap— but that belong to other roadmaps. For example, with regard to 2.4.5. Power, the roadmap says:

Power systems play an integral role in all in-space propulsion systems for both human and robotic missions. The reader is referred to the Technology Area 3, Space Power and Energy Storage Systems.

Similarly, with regard to technologies 2.4.1, 2.4.3, and 2.4.4, roadmap TA02 refers readers to roadmaps TA04, TA12, and TA14, respectively, to learn the details of what should be done in these areas.


The panel identified four top technical challenges for TA02, all of which are related to the provision of safe, reliable, and affordable in-space transportation consistent with NASA’s mission needs. The challenges are listed below in priority order.

1 High-Power Electric Propulsion (EP) Systems: Develop high-power EP system technologies to enable high-ΔV missions with heavy payloads.

EP systems have a higher propellant efficiency than other in-space propulsion technologies that will be available in the foreseeable future, with applications to all NASA, Department of Defense (DOD), and commercial space

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