Scientists and Engineers are working to develop a propulsion system utilizing Carbon Dioxide, CO2, as an oxidizer to generate energy. A departure from conventional combustion of Hydrocarbons that produces CO2 as by-product of combustion.
One such attempt is underway at the University of Hertfordshire where they are working to develop a prototype Engine to demonstrate the feasibility of using such an Engine to power future missions to Mars. If successfully developed, it would essentially halve the required amount of fuel needed to be carried by these Spacecraft, as the Carbon Dioxide needed for the return flight could be captured from the Martian atmosphere itself - a major breakthrough since this would greatly reduce the total weight of the spacecraft, economizing the use of fuel needed to generate required thrust to propel such a craft.
Can watch the concept being explained in this video [Duration: approximately 6 minutes]
Solution essentially proposes igniting finely divided Aluminum, supported by CO2 as an oxidizer to generate heat. Here, the choice of the oxidizer borne solely out of its easy availability in the Martian atmosphere.
4Al + 3CO2 -> 2Al2O3 + 3C + Heat [exothermic]
Nothing new about the reaction - known since ages, but the challenge lies in putting it to practical use. Some issues, I foresee, that need to be addressed before such a propulsion system can be put to practical application - amount of specific energy generated which would determine the size of the system, ability to effectively control the process of generating energy & just as important, IMO, the cost-effectiveness of such a solution.
The use of such engines on Earth, however, need not necessarily be a solution to current problems. CO2 is a much-needed greenhouse gas needed to maintain optimum temperature on the Earth's surface sustaining life. Even though its increasing levels in the atmosphere is a cause of concern now-a-days, removing it from the atmosphere that could lead to a situation where you remove more than you produce, if it were to ever reach that stage, could prove to be quite catastrophic. Its more of a specific solution for a specific application type scenario.
Not to anybody's surprise I guess, the research at the University of Herefordshire involves an Indian [or at least a person of Indian origin] Sathyakumar Sharma who had previously worked with the Indian Space Research Organization [ISRO]. With so many Indian sounding names popping up in almost every other eye-popping experiment or research being carried out around the world, I cannot help but feel that India must find a suitable way to leverage this to gain from their expertise, and, more importantly, their experience to aid & fuel its own programs. Crowdsourcing, short-term focused project groups, mentorship could be some of the ways to achieve this. Been reading news of a reverse brain drain happening in India - need to incentivize/accelerate this through the implementation of smart policies.
Godspeed
Possibly related posts:
Nukes in Space: Rainbow bombs [Documentary]
Space Agencies & Manned Moon missions: International Astronautical Congress 2009
Design Engineers, I.T. and Crowdsourcing
Pranav Mistry talking about Sixth Sense at TED India 2009