DEEP-IN, also known as Directed Energy Propulsion for Interstellar Exploration, is a spaceflight propulsion concept that uses photonic laser propulsion with beamed power to propel a spacecraft in deep space. The concept was originally conceived by Professor Philip Lubin of the University of California Santa Barbara's Physics Department. Lubin is developing it under the NASA Innovative Advanced Concepts Program.[1] DEEP-IN is notable as the first NASA-backed photonic laser propulsion concept. It is heavily derived from DE-STAR, a planetary defense satellite concept previously developed by Lubin, in which he proposes using directed energy from lasers to vaporize or knock off course destructive asteroids headed for Earth.[2][3][4][5]

The system is scalable and modular, so that gradually larger objects can be propelled into space at relativistic speeds (speeds that are a significant fraction of the speed of light) with increasingly powerful lasers.[6] Currently, research models suggest that using this technology, a satellite massing 100 kilograms (220 lb) could reach Mars in 3 days, a significantly shorter time than the current transit time. Additionally, a more massive crewed spacecraft, such as the Orion spacecraft, could reach Mars in one month, compared to the traditional requirement of around 5 months.[7] However, News Ledge notes that this short transfer time would require a second array of lasers already existing on Mars to slow vehicles down for Mars orbital insertion.[8]


DEEP-IN would use an array of small lasers to focus a stream of photons onto reflectors on spacecraft, eliminating the need for spacecraft to carry propellant and therefore significantly lowering their mass. Photon momentum would be translated to the spacecraft, and reflectors enable a theoretical twofold increase in momentum transfer compared to a blackbody surface. The project anticipates it could carry femtosatellites weighing grams at approximately 0.25 times the speed of light, and still have significant maximum speed on larger spacecraft.[9]


Lubin has been furthering this concept under two grants to date from the NASA Institute for Advanced Concepts - a Phase 1 grant in 2015 of $100,000,[9] and a Phase 2 grant in 2016 of US$500,000.[10]


  1. ^ Lubin, Phillip (13 May 2016). "Directed Energy Interstellar Study". Retrieved 22 October 2016.
  2. ^ "DEEP-IN". UCSB Experimental Cosmology Group. Archived from the original on 12 April 2016. Retrieved 26 February 2016.
  3. ^ "DEEP IN Directed Energy Propulsion for Interstellar Exploration". Next Big Future. 11 May 2015. Retrieved 26 February 2016.
  4. ^ Lubin, Phillip (7 May 2015). "DEEP IN Directed Energy Propulsion for Interstellar Exploration". NASA Features. Retrieved 26 February 2016.
  5. ^ Cohen, Julie (23 June 2015). "Team to investigate possibility of using directed energy propulsion for interstellar travel". Retrieved 26 February 2016.
  6. ^ Gough, Evan (23 February 2016). "NASA thinks there's a way to get to Mars in 3 days". Universe Today. Retrieved 26 February 2016.
  7. ^ Bennet, Jay (24 February 2016). "Photonic Propulsion Could Send a Spacecraft to Mars in As Little As 3 Days". Popular Mechanics. Retrieved 26 February 2016.
  8. ^ Chaver, Alex (23 February 2016). "Photonic Propulsion could get us to Mars in a month, but..." News Ledge. Retrieved 26 February 2016.
  9. ^ a b Thompson, Ben. "3 days to Mars: How laser propulsion could revolutionize space travel". Christian Science Monitor. ISSN 0882-7729. Retrieved 2016-02-26.
  10. ^ Anderson, Gina (13 May 2016). "Magnetoshells to Growable Habitats, NASA Invests in Visionary Tech". Retrieved 22 October 2016.