Will LED's power future spacecraft?
UV LED (ultraviolet light emitting diodes) are used extensively in today's manufacturing of high-tech items, commonly for (high speed) curing of epoxies or resins. Could ultraviolet LEDs be configured to provide substantial propulsion?
Ridiculous, impossible? Light produced by LEDs is not considered a form of propulsion; high-powered flashlights do not act like rockets!
While intense light itself cannot offer sufficient thrust to propel a craft through space, gas emitting polymers, combined with high output LED arrays can offer stable solid-to-gas fuel supplies for extended journeys. Advancements in photo reactive gas emitting polymers, combined with ultra-efficient ultraviolet LED arrays, may be an effective propulsion system for future “Long-haul” spacecraft.
If this seems a little far-fetched to you, consider Mark Banister (Tucson, AZ, US) : According to his recently filed patent describing a micro thruster, utilizing an
“Ultraviolet light source, (possibly LED)” triggers a Gas Generating Polymeric Compound, this causes a “solid-to-gas phase transition due to chemically catylized degradation” there are several existing polymeric candidates available depending on the type of gas production desired.
” Acetal resin or Polyoxymethylene is mixed with photo acid generators or its chain end capped with photo initiators. The polymer readily decomposes to the gas formaldehyde both in the presence of acids and UV radiation. Acetal resin is also attractive for its ability to be engineered and copolymerized. This allows the reaction gas or products to be engineered to produce a highly energetic and reactive gas.”
In summary: gas emitting polymeric compounds (plastics) can be directly layered onto UV LED arrays to become very durable (explosion proof?), because of the minimal heat generated by the LED arrays engine housings can be fabricated directly onto gas generating arrays. The emitted gas can be cold-streamed using high pressure nozzles, or depending on the type of gas emitted, igniters could be used to create ignition thrust.
But how does the fuel energy density (J/gm) of the polymer compare w traditional rocket fuel? Watch for this exciting LED-based propulsion to be announced soon!