Long a fixture of many lunar settlement visions, the Mass Launcher or Mass Driver is an electromagnetic accelerator system that propels payloads to orbital velocity using electric power and magnetic levitation. This is the same technology originally proposed for the Bifrost Mass Launcher of the original TMP, though that particular system concept proved unworkable. It is more likely that terrestrial mass launchers may be limited to extremely large straight track systems serving as horizontal boosters for space planes or rockets, relying on possible thermal air-spike aerodynamic shielding of launch capsules, or employ more modest scale circular accelerators suited to very small, frequent, simple payloads of basic materials like ice or alloys.
This has been a popular strategy for bulk transportation of lunar materials owing to the long-standing belief of a total lack of water on the Moon that might be converted to propellant. More recent science may change the perspective on this given the discovery of significant ice deposits, but the technology still has a great advantage in efficiency and is likely to be used where a demand for bulk lunar material –over asteroid materials– is realized. It also has potential for similar use on Mars –with the addition of streamlined payload carriers– and in orbital space as a means of transporting asteroid materials and general transit in the form of the Ballistic Railway Network.
A straight track lunar mass launcher is the simplest proposed system as it can be based on a series of relatively self-contained magnetic accelerator modules –possibly employing their own deployable solar power systems at small scales– that would be placed on the lunar surface using laser alignment. This simple construction would be suited to teleoperated robotics. A circular launcher would be more compact but require both a closely spaced series of secondary field coils to aid in resisting centrifugal deflection as payloads accelerate and a much more massive physical structure, making it more complex to construct and likely to employ excavated structures. Likely initially limited to bulk materials launch, payloads would employ packaging of materials as durable solids or encapsulates to which both an accelerator coil and a small expendable rocket can be physically integrated or retrofit, the small rocket used to circularize the payload orbit. Such payload packaging would demand a sophisticated mass production system and it may be some time before initial mass launcher systems achieve the very high continuous launch rates often attributed to them in the past (largely to suit very ambitious orbital colony construction period projections…) because of payload preparation overhead. It may simply not be practical to produce payloads as fast as these systems might be capable of launching them, though this is, of course, a matter of production systems scale and automation.
There is some possibility for passenger transit even for straight track mass launcher systems but the need for lower rates of acceleration for passengers would require use of a much longer track. There is a key limitation for a passenger system in that any passenger launch capsule would need to be more sophisticated than a cargo capsule and quite large to be reusable, since it would have to return to the surface using conventional propulsion systems it must carry with it. So it is more likely that this technology would be limited for some time to materials transit where launch capsule packaging can be treated as recyclable at its destination. This, would, however, eventually become a practical option even for passenger vehicles with the advent of total recycling by nanotechnology.
A key factor in mass launcher design that is often overlooked is the payload capture on orbit, given the lack of active propulsion with high volume payload packaging. This too is a critical potential bottleneck in achieving very high launch frequencies. But with a very predictable trajectory, the ‘flow’ of payload traffic can be quite orderly and suited to automated recovery as well as launch.
One possible capture station design would adapt the same ‘beamship’ space frame architecture employed with many of the vehicles and stations of the Asgard phase and employed with lunar and planetary way-station facilities. A large space frame truss would be fashioned in the shape of a very wide polygonal section tube –perhaps over 100 meters wide– aligned parallel to the orbital trajectory of incoming payloads. A series of long telescoping InchWorm robot arms within the truss would be equipped with special grapplers with a spherical contraction form akin to a Hoberman sphere and fast-response actuators guided by lidar tracking. Like the feeding legs of a barnacle, these arms would capture incoming payload capsules in rapid succession as they drift at a moderate speed through the wide middle space of the truss then pull them to the inner side of the truss where they would be transferred to conveyors that would carry them to the outside of the truss for temporary stack storage and transfer to inter-orbital transit vessels or an attached MOUF complex for processing. Payloads missed as they pass through the capture station would remain in orbit for attempted interception later, the surface launch interval interrupted to account for the missed unit.
Though the basic principles of mass launcher systems are well understood, little full scale experimentation in this application has ever been done in the history of spaceflight and, though a common fixture in space settlement schemes, we must treat it as somewhat speculative. Thus while we anticipate its use in TMP2, we must not assume it to be an inevitability and we may find that the economic practicality of this launch technology may still not compare to intensive asteroid mining. In Avalon we assume the use of most indigenous resources on the Moon, Mars, and similar bodies for settlements right there. But it is clear that the great efficiencies of electric powered propulsion will likely give it a prominent position in future space transportation in various forms, and the mass launcher is still a likely form.
- Life In Avalon
- Telerobotic Outpost
- Excavated Settlement
- Excavated Colonies
- Surface Shuttle Vehicles
- Surface Transit Way-Station
- Lunar/Planetary Space Elevator Systems
- Avalon Supporting Technologies