They told the businessmen that he would be able to make a profit by selling the item to the space agency.
Police told Indian media the men passed off the metal plate as a "rare piece of copper", which they said was "struck by thunderbolt" giving the ability to attract rice.
The accused have now been arrested from Dwarka by the Delhi Police.
"Cheats take a copper plate or utensil and coat it with liquid magnet and then fill some boiled rice with small iron wires and fool the victim by pulling the iron-clad rice grain with the magnet coated copper article", India Today quoted Alok Kumar, joint commissioner of police, crime branch.
The victim met Virender Mohan Brar, managing director of a company, who told him that his company could arrange the sale of RP' to NASA at a price of around Rs 37,500 crore after testing its genuineness, which would be done by scientists of the DRDO and some chemicals would be imported for it, police said.
The victim then signed an agreement with Brar and Mohan and paid an additional Rs 51 lakh so that the tests and other requirements could be completed.
Delhi Police say at least 30 people fell for the swindle, and paraded the pair in their crinkly silver outfits for the press.
The British newspaper reported the businessman went to police after handing over more than $260,000. He again entered into an MoU and paid Rs 5.6 lakh, Rs 3.5 lakh and Rs 42 lakh for the same stuff he had paid earlier. But at that time, the testing was not conducted by the accused persons stating that the sky was not clear. This is when the victim realised he cheated by the so-called scientists. Later, the victim came to know that the said scientist' was working with the accused for Rs 20,000, police said. The duo spun a yarn about procuring a metal called "Rice Puller" which was highly sought after by NASA.
According to reports, last month, the victim engaged in garments export approached Crime Branch on coming to realise that the scientific tests were being constantly postponed.
During probe, the alleged RP copper plate, anti-radiation suits from NASA and anti-radiation chemical stickers were recovered along laptop, printer, blank letter heads of Rehan Metals, US, one Audi vehicle from the accused.