New Lithium-Plasma Engine Passes Key Mars Propulsion Test (universetoday.com) 16
NASA engineers have tested a next-generation lithium-plasma electric propulsion system that reached 120 kilowatts, a new U.S. record and about 25 times the power of the electric thrusters on NASA's Psyche spacecraft. "Designing and building these thrusters over the last couple of years has been a long lead-up to this first test," said James Polk, who is a senior research scientist at NASA Jet Propulsion Laboratory. "It's a huge moment for us because we not only showed the thruster works, but we also hit the power levels we were targeting. And we know we have a good testbed to begin addressing the challenges to scaling up." Universe Today reports: While 120 kilowatts is a new record, NASA estimates it a future human mission to Mars will require 2 to 4 megawatts of power consisting of several thrusters and requiring more than 23,000 hours (958 days/2.6 years) of operation. To accomplish this, the thrusters would have to withstand more than 2,800 degrees Celsius (5,000 degrees Fahrenheit), which the thrusters achieved during testing.
The reason for the extended operation is due to the estimated time of an entire human mission to Mars, which is estimated to be approximately 2.6 years. This is because the launch window to Mars only opens once every two years due to the orbital behaviors of both planets. While no mission has ever returned from the Red Planet, this same launch window works from Mars to Earth, too. When launched within this window, robotic spacecraft have traditionally taken approximately 6-7 months to reach Mars.
However, a human mission would require a much larger spacecraft to accommodate the astronauts, food, fuel, water, and other mission-essential items. For the approximate 2.6-year mission, this would entail approximately 6-9 months traveling to Mars, followed by approximately 18 months on the surface of Mars until the next launch window opens, then another approximate 6-9 months back to Earth. However, having much less fuel due to the electric propulsion system could potentially alter this timeframe.
The reason for the extended operation is due to the estimated time of an entire human mission to Mars, which is estimated to be approximately 2.6 years. This is because the launch window to Mars only opens once every two years due to the orbital behaviors of both planets. While no mission has ever returned from the Red Planet, this same launch window works from Mars to Earth, too. When launched within this window, robotic spacecraft have traditionally taken approximately 6-7 months to reach Mars.
However, a human mission would require a much larger spacecraft to accommodate the astronauts, food, fuel, water, and other mission-essential items. For the approximate 2.6-year mission, this would entail approximately 6-9 months traveling to Mars, followed by approximately 18 months on the surface of Mars until the next launch window opens, then another approximate 6-9 months back to Earth. However, having much less fuel due to the electric propulsion system could potentially alter this timeframe.
Mars is waste of resources. (Score:3)
We should build industry on the Moon first and do cheaper robotic exploration.
And save the Earth - the only livable planet we will have in the near future...
Re: Mars is waste of resources. (Score:2)
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All right! (Score:2)
We're that much closer to Mars-grown potatoes!
120 kW (Score:3)
Is that 120kW of thrust, or are they reporting it in the same way we hear about datacentres - in terms of input power consumption rather than useful work?
Genuine question, because it doesn't say in the linked article and I can't be arsed to watch a damned youtube video
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The video is only 50 seconds long and doesn't answer your question exactly.
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The 120kW figure is indeed input power. Thrust is typically quoted in Newtons, not Watts. The input power is useful because it's a proxy for thrust and vastly easier to measure. Ultimately, none of that really matters, however: the real figure of merit for ion engines (all rockets, really) is Specific Impulse. When NASA claims these use 90% less mass for the same total impulse, they're saying it's about one order of magnitude more propellant-efficient than a chemical rocket.
Not 2.6 years of operation (Score:3)
requiring more than 23,000 hours (958 days/2.6 years) of operation
For the approximate 2.6-year mission, this would entail approximately 6-9 months traveling to Mars, followed by approximately 18 months on the surface of Mars until the next launch window opens, then another approximate 6-9 months back to Earth.
Why are the thrusters running during the 18 months at Mars? Mars has a much thinner atmosphere, so at any reasonable altitude any spacecraft in orbit will encounter much less drag than on the ISS around Earth. The ISS does not run its thrusters continuously; it gets an occasional boost from a Soyuz. And there isn't much space debris around Mars compared with LEO, so not much to dodge. If the entire spacecraft lands, it's definitely not running its thrusters the entire time.
So that's 12-18 months (1 - 1.5 years) of operation, only when it's headed to Mars or back. Half the quoted amount.
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Why are the thrusters running during the 18 months at Mars?
It's needed for the Purnell Maneuver.
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But they might want to idle the thrusters for 18 months, to prevent the thrusters going cold.
It would be very tough to return to Earth (Score:2)
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It would be much less expensive to put some mice in a rotating orbital habitat to see what low g does to a mammal than to send humans on long term missions to the Moon or Mars, but other than one limited Japanese experiment nobody seems interested in doing so.
That tells me that nobody is yet serious about such missions.
How much actual thrust is produced? (Score:1)
Re: How much actual thrust is produced? (Score:2)