A Number That Sums It Up: 3 to 4 months to Mars
What if a spacecraft may get to Mars in half the time it at the moment takes?
Every 26 months or so, Mars and Earth are shut sufficient for a shorter journey between the worlds. But even then it’s a fairly lengthy journey, lasting seven to 9 months. For more often than not, the spacecraft is simply coasting by area.
But if the spacecraft may proceed accelerating by the primary half of the journey after which begin slowing down once more, the journey time could possibly be slashed. Current rocket engines, which generally depend on the combustion of a gas like hydrogen or methane with oxygen, will not be environment friendly sufficient to perform that; there may be not sufficient room within the spacecraft to hold that a lot propellant.
But nuclear reactions, producing vitality from the splitting of uranium atoms, are rather more environment friendly.
The DRACO engine would include a nuclear reactor that may warmth hydrogen from a cold minus 420 levels Fahrenheit to a toasty 4,400 levels, with the recent gasoline taking pictures from a nozzle to generate thrust. Greater gas effectivity may velocity up journeys to Mars, lowering the period of time astronauts spend uncovered to the treacherous setting of deep area.
Nuclear propulsion may even have makes use of nearer to residence, which is why DARPA is investing within the venture. The know-how might enable speedy maneuvers of army satellites in orbit round Earth.
Background: Back to the long run
Nuclear propulsion for area is just not a brand new concept. In the Nineteen Fifties and Nineteen Sixties, Project Orion — financed by NASA, the Air Force and the Advanced Research Projects Agency — contemplated utilizing the explosions of atomic bombs to speed up spacecraft.
At the identical time, NASA and different companies additionally undertook Project Rover and Project NERVA, efforts that aimed to develop nuclear-thermal engines comparable in idea to these now being pursued by the DRACO program. A collection of 23 reactors had been constructed and examined, however none had been ever launched to area. Until the top of this program in 1973, NASA had contemplated utilizing nuclear reactors to propel area probes to Jupiter, Saturn and past, in addition to to offer energy at a lunar base.
“The technical capabilities, including early safety protocols, remain viable today,” Tabitha Dodson, the DRACO venture supervisor, mentioned in a news briefing on Wednesday.
A key distinction between NERVA and DRACO is that NERVA used weapons-grade uranium for its reactors, whereas DRACO will use a less-enriched type of uranium.
The reactor wouldn’t be turned on till it reached area, a part of the precautions to attenuate the potential of a radioactive accident on Earth.
“DRACO has already done all of our preliminary analyses across the entire spectrum of possibilities for accidents and found that we’re all the way down in the low probability and all the way down in the teeny tiny amount of release,” Dr. Dodson mentioned.
What Happens Next: A take a look at flight in orbit
The DRACO improvement is to culminate with a flight take a look at of the nuclear-thermal engine. Kirk Shireman, a vp at Lockheed Martin, mentioned the launch was at the moment scheduled for late 2025 or early 2026.
The demonstration spacecraft would most probably orbit at an altitude between 435 and 1,240 miles, Dr. Dodson mentioned. That is excessive sufficient to make sure that it stays in orbit for greater than 300 years, or lengthy sufficient for radioactive parts within the reactor gas to decay to secure ranges, she mentioned.
Source: www.nytimes.com