Ten times faster lithium ion thrusters will be tested at JPL within 6 months

50000 ISP lithium ion thrusters will be tested at JPL within 6 months.

NASA NIAC phase 2 study to use lasers to beam 10 megawatts of power to power new ion drives. This will enable a system to go ten times faster than any previous space mission. This will go 40 AU per year. It would take less than year to get to Pluto.

They are building and proving out the various components of this system. The sail and the ion drives are coming together. The hard part is the phased array lasers.

They are boosting the testing voltage up to 6000 volts so the lithium ion drives can be directly driven. Direct drive eliminates the need for a lot of heavy electronics which would kill the performance.

The phased array lasers will increase the power density over the solar density by 100 times.

Going from a laser wavelength of 1063 nanometers down to 300 nanometers would reduce the needed power and system size.

35 thoughts on “Ten times faster lithium ion thrusters will be tested at JPL within 6 months”

  1. > Array cells tuned to the laser frequency for efficiency > 50{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12}””Did they remember to account for doppler shift? Are they planning to tune the laser frequency as the craft accelerates? Or is the doppler shift too small to matter?”””

    Reply
  2. It would be cheaper to go to Mars with a resistant heated rocket. An ISP of a 1000+ would be enough. Maximizing the ISP does not maximize the payload. It reduces the amount of fuel but it also increases the weight of the equipment needed to collect energy and radiate heat. Weight and Cost goes up by the square of the Isp. So you get there as fast as you need to and no faster.

    Reply
  3. Laser power is doubling about every 4 years while price per MW is going down. Beamed power is a possibility for from earth to space and also a possibility for going further.

    Reply
  4. Just looking at the distance between orbits – 5 days to 3 weeks depending on where the planets are in relation to each other. Of course you want to decelerate at the other end, so double that. In human scale, that’s like crossing the Atlantic on steam ship at the low end or sailing ship on the high end. Very doable. We’ll see how the technology plays out, I’m sure there are many unanticipated technical issues that haven’t been addressed.

    Reply
  5. Mars is 0.5-2.5 AU away. At 40 AU/year that would take ~5-25 days. But since at these distances it’ll still be in the acceleration phase, let’s call that a couple months. Which isn’t much better than chemical propulsion with refueling, which has much shorter acceleration times (more thrust), but then coasts most of the way. Also I expect the payload will be really small. Otherwise it’ll need more thrust, which will need more power.

    Reply
  6. > “Array cells tuned to the laser frequency for efficiency > 50%” Did they remember to account for doppler shift? Are they planning to tune the laser frequency as the craft accelerates? Or is the doppler shift too small to matter?

    Reply
  7. It would be cheaper to go to Mars with a resistant heated rocket. An ISP of a 1000+ would be enough. Maximizing the ISP does not maximize the payload. It reduces the amount of fuel but it also increases the weight of the equipment needed to collect energy and radiate heat. Weight and Cost goes up by the square of the Isp. So you get there as fast as you need to and no faster.

    Reply
  8. Laser power is doubling about every 4 years while price per MW is going down. Beamed power is a possibility for from earth to space and also a possibility for going further.

    Reply
  9. Just looking at the distance between orbits – 5 days to 3 weeks depending on where the planets are in relation to each other. Of course you want to decelerate at the other end so double that. In human scale that’s like crossing the Atlantic on steam ship at the low end or sailing ship on the high end. Very doable.We’ll see how the technology plays out I’m sure there are many unanticipated technical issues that haven’t been addressed.

    Reply
  10. Mars is 0.5-2.5 AU away. At 40 AU/year that would take ~5-25 days. But since at these distances it’ll still be in the acceleration phase let’s call that a couple months. Which isn’t much better than chemical propulsion with refueling which has much shorter acceleration times (more thrust) but then coasts most of the way.Also I expect the payload will be really small. Otherwise it’ll need more thrust which will need more power.

    Reply
  11. Assuming the lithium ions will be positively charged, won’t there be a need to bleed off extra electrons, so the craft does not accumulate a large negative charge, attracting the ion plume? Doing so would minimize undesirable interaction with the lithium ion plume. I’d first model an electron gun beside each ion thruster with the electron beam parallel to the ion beam with an energy calculated to give the electrons similar velocity to the ions, so they could recombine, eliminating the ion plume. If the electron guns prove to be too heavy, perhaps a ring of bucky-tube fuzz around the circumference of the craft to emit them.

    Reply
  12. Assuming the lithium ions will be positively charged won’t there be a need to bleed off extra electrons so the craft does not accumulate a large negative charge attracting the ion plume? Doing so would minimize undesirable interaction with the lithium ion plume. I’d first model an electron gun beside each ion thruster with the electron beam parallel to the ion beam with an energy calculated to give the electrons similar velocity to the ions so they could recombine eliminating the ion plume. If the electron guns prove to be too heavy perhaps a ring of bucky-tube fuzz around the circumference of the craft to emit them.

    Reply
  13. Assuming the lithium ions will be positively charged, won’t there be a need to bleed off extra electrons, so the craft does not accumulate a large negative charge, attracting the ion plume? Doing so would minimize undesirable interaction with the lithium ion plume. I’d first model an electron gun beside each ion thruster with the electron beam parallel to the ion beam with an energy calculated to give the electrons similar velocity to the ions, so they could recombine, eliminating the ion plume. If the electron guns prove to be too heavy, perhaps a ring of bucky-tube fuzz around the circumference of the craft to emit them.

    Reply
  14. Assuming the lithium ions will be positively charged won’t there be a need to bleed off extra electrons so the craft does not accumulate a large negative charge attracting the ion plume? Doing so would minimize undesirable interaction with the lithium ion plume. I’d first model an electron gun beside each ion thruster with the electron beam parallel to the ion beam with an energy calculated to give the electrons similar velocity to the ions so they could recombine eliminating the ion plume. If the electron guns prove to be too heavy perhaps a ring of bucky-tube fuzz around the circumference of the craft to emit them.

    Reply
  15. It would be cheaper to go to Mars with a resistant heated rocket. An ISP of a 1000+ would be enough. Maximizing the ISP does not maximize the payload. It reduces the amount of fuel but it also increases the weight of the equipment needed to collect energy and radiate heat. Weight and Cost goes up by the square of the Isp. So you get there as fast as you need to and no faster.

    Reply
  16. It would be cheaper to go to Mars with a resistant heated rocket. An ISP of a 1000+ would be enough. Maximizing the ISP does not maximize the payload. It reduces the amount of fuel but it also increases the weight of the equipment needed to collect energy and radiate heat. Weight and Cost goes up by the square of the Isp. So you get there as fast as you need to and no faster.

    Reply
  17. Laser power is doubling about every 4 years while price per MW is going down. Beamed power is a possibility for from earth to space and also a possibility for going further.

    Reply
  18. Laser power is doubling about every 4 years while price per MW is going down. Beamed power is a possibility for from earth to space and also a possibility for going further.

    Reply
  19. Just looking at the distance between orbits – 5 days to 3 weeks depending on where the planets are in relation to each other. Of course you want to decelerate at the other end, so double that. In human scale, that’s like crossing the Atlantic on steam ship at the low end or sailing ship on the high end. Very doable. We’ll see how the technology plays out, I’m sure there are many unanticipated technical issues that haven’t been addressed.

    Reply
  20. Just looking at the distance between orbits – 5 days to 3 weeks depending on where the planets are in relation to each other. Of course you want to decelerate at the other end so double that. In human scale that’s like crossing the Atlantic on steam ship at the low end or sailing ship on the high end. Very doable.We’ll see how the technology plays out I’m sure there are many unanticipated technical issues that haven’t been addressed.

    Reply
  21. Mars is 0.5-2.5 AU away. At 40 AU/year that would take ~5-25 days. But since at these distances it’ll still be in the acceleration phase, let’s call that a couple months. Which isn’t much better than chemical propulsion with refueling, which has much shorter acceleration times (more thrust), but then coasts most of the way. Also I expect the payload will be really small. Otherwise it’ll need more thrust, which will need more power.

    Reply
  22. Mars is 0.5-2.5 AU away. At 40 AU/year that would take ~5-25 days. But since at these distances it’ll still be in the acceleration phase let’s call that a couple months. Which isn’t much better than chemical propulsion with refueling which has much shorter acceleration times (more thrust) but then coasts most of the way.Also I expect the payload will be really small. Otherwise it’ll need more thrust which will need more power.

    Reply
  23. > “Array cells tuned to the laser frequency for efficiency > 50%” Did they remember to account for doppler shift? Are they planning to tune the laser frequency as the craft accelerates? Or is the doppler shift too small to matter?

    Reply
  24. > Array cells tuned to the laser frequency for efficiency > 50{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12}””Did they remember to account for doppler shift? Are they planning to tune the laser frequency as the craft accelerates? Or is the doppler shift too small to matter?”””

    Reply
  25. Assuming the lithium ions will be positively charged, won’t there be a need to bleed off extra electrons, so the craft does not accumulate a large negative charge, attracting the ion plume? Doing so would minimize undesirable interaction with the lithium ion plume. I’d first model an electron gun beside each ion thruster with the electron beam parallel to the ion beam with an energy calculated to give the electrons similar velocity to the ions, so they could recombine, eliminating the ion plume. If the electron guns prove to be too heavy, perhaps a ring of bucky-tube fuzz around the circumference of the craft to emit them.

    Reply
  26. It would be cheaper to go to Mars with a resistant heated rocket. An ISP of a 1000+ would be enough.

    Maximizing the ISP does not maximize the payload. It reduces the amount of fuel but it also increases the weight of the equipment needed to collect energy and radiate heat. Weight and Cost goes up by the square of the Isp.

    So you get there as fast as you need to and no faster.

    Reply
  27. Just looking at the distance between orbits – 5 days to 3 weeks depending on where the planets are in relation to each other. Of course you want to decelerate at the other end, so double that. In human scale, that’s like crossing the Atlantic on steam ship at the low end or sailing ship on the high end. Very doable.
    We’ll see how the technology plays out, I’m sure there are many unanticipated technical issues that haven’t been addressed.

    Reply
  28. Mars is 0.5-2.5 AU away. At 40 AU/year that would take ~5-25 days. But since at these distances it’ll still be in the acceleration phase, let’s call that a couple months. Which isn’t much better than chemical propulsion with refueling, which has much shorter acceleration times (more thrust), but then coasts most of the way.

    Also I expect the payload will be really small. Otherwise it’ll need more thrust, which will need more power.

    Reply
  29. > “Array cells tuned to the laser frequency for efficiency > 50%”

    Did they remember to account for doppler shift? Are they planning to tune the laser frequency as the craft accelerates? Or is the doppler shift too small to matter?

    Reply

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