McGill University scientists designed a solicitation. The laser is a 10-meter-wide array on Earth. It would heat hydrogen plasma in a chamber behind the spacecraft. It will produce thrust from hydrogen gas and sending it to Mars in only 45 days. It would aerobrake in Mars’ atmosphere. It would shut supplies to human colonists.
NASA challenged engineers to design a mission to Mars that would deliver a payload of at least 1,000 kilograms in no more than 45 days. The short delivery time is motivated by a desire to ferry shipments. Astronauts’ exposure to the damaging effects of galactic cosmic rays and solar storms will be minimized. Elon Musk’s SpaceX envisions a human trip to Mars would take six months.
McGill’s concept is known as laser-thermal propulsion. It relies on an array of infrared lasers based on Earth. It is 10 meters in diameter, combining many invisible infrared beams. Its electric power required for about 80,000 U.S. households. The payload would have a reflector. It will direct the laser beam coming from Earth into a heating chamber containing a hydrogen plasma. Its core is heated as high as 40,000 degrees Kelvin. Hydrogen gas will flow around the core would reach 10,000 K. It will be expelled out a nozzle. It will create thrust to propel the ship away from Earth over an interval of 58 minutes.
The payload zips away at a velocity of almost 17 kilometers per second relative to Earth. It is fast enough to go past the moon’s orbital distance in a mere eight hours. It reaches the Martian atmosphere in a month and a half. It then places the payload in a 150-km orbit around Mars. But it was a difficult problem for the engineering team to solve.
The payload can’t carry a chemical propellant to fire a rocket to slow itself down. The fuel needed would reduce the payload mass to less than 6 percent of the original 1,000 kilograms. Humans on Mars have to construct an equivalent laser array for the incoming craft to use its reflector.
The aerobraking in Mars’ atmosphere could be a dicey maneuver. Spacecraft experiences decelerations of up to 8 g. it is captured within a single pass around Mars. The large heat fluxes on the craft because of atmospheric friction. It would be above traditional thermal protection system materials.
Laser-thermal propulsion of spacecraft into deep space. Contrast with other previously proposed methods of conveyance. a laser beam would impinge on photovoltaic cells behind the payload.
