Momentus Space: Last 1 km/s Delivery

[IncongruousGoat]

It doesn't look like there's a thread for these folks yet, so here goes: https://momentus.space

Basically, they're working on electric-propulsion space tugs (microwave electrothermal propulsion with water as the propellant) for use on rideshare missions, to deliver the launched satellites to various destination orbits beyond whatever the launch vehicle would have been capable of. They seem pretty legit too, given that they've managed to get contracts from actual satellite manufacturers for launches with slots on actual launch manifests.

Thoughts? Personally I'm very excited, but I'm curious to see what you all think about this.

 

Edited July 18, 2020 by IncongruousGoat
Typo

[mikegarrison]

  On 7/18/2020 at 1:34 AM, IncongruousGoat said:

It doesn't look like there's a thread for these folks yet, so here goes: https://momentus.space

Basically, they're working on electric-propulsion space tugs (microwave electrothermal propulsion with water as the propellant) for use on rideshare missions, to deliver the launched satellites to various destination orbits beyond whatever the launch vehicle would have been capable of. They seem pretty legit too, given that they've managed to get contracts from actual satellite manufacturers for launches with slots on actual launch manifests.

Thoughs? Personally I'm very excited, but I'm curious to see what you all think about this.

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So this would replace or supplement integrated propulsion systems on satellite buses?

[IncongruousGoat]

  On 7/18/2020 at 2:54 AM, mikegarrison said:

So this would replace or supplement integrated propulsion systems on satellite buses?

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More like provide a temporary propulsion bus for a bunch of rideshare smallsats for final orbital placement purposes. So, LV dumps smallsat dispenser + tug into LEO somewhere, tug then moves dispenser around dispensing smallsats into target orbits.

[DDE]

  On 7/18/2020 at 1:34 AM, IncongruousGoat said:

It doesn't look like there's a thread for these folks yet, so here goes: https://momentus.space

Basically, they're working on electric-propulsion space tugs (microwave electrothermal propulsion with water as the propellant) for use on rideshare missions, to deliver the launched satellites to various destination orbits beyond whatever the launch vehicle would have been capable of. They seem pretty legit too, given that they've managed to get contracts from actual satellite manufacturers for launches with slots on actual launch manifests.

Thoughs? Personally I'm very excited, but I'm curious to see what you all think about this.

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A miniature, explosion-safe upper stage? Definitely a workable niche, none of the voodoo associated with, say, ARCA and their resistojet strap-on boosters.

[magnemoe]

  On 7/18/2020 at 3:04 AM, IncongruousGoat said:

More like provide a temporary propulsion bus for a bunch of rideshare smallsats for final orbital placement purposes. So, LV dumps smallsat dispenser + tug into LEO somewhere, tug then moves dispenser around dispensing smallsats into target orbits.

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Yes, my problem with it is the power use, this is an electrical drive like ion so they need some good sized solar panels who add weight. 
 

Edited July 18, 2020 by magnemoe

[IncongruousGoat]

  On 7/18/2020 at 2:59 PM, magnemoe said:

Yes, my problem with it is the power use, this is an electrical drive like ion so they need some good sized solar panels who add weight. 
 

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It looks like the thruster design they're using (plasma, not ion) has a lower Isp than a typical ion thruster (~1000s vs. 3000-5000s), but also a lower power requirement per kN of thrust.

Also, they're only trying to get 1 km/s out of their first model, which gives them some margin for heavy solar panels.

Edited July 18, 2020 by IncongruousGoat

[magnemoe]

  On 7/18/2020 at 3:15 PM, IncongruousGoat said:

It looks like the thruster design they're using (plasma, not ion) has a lower Isp than a typical ion thruster (~1000s vs. 3000-5000s), but also a lower power requirement per kN of thrust.

Also, they're only trying to get 1 km/s out of their first model, which gives them some margin for heavy solar panels.

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Yes, its 1000s, but they also need more than 10x ion trust to not get stuck in the radiation belt. 
I like the idea a lot however. Down the line you could probably beam power. An laser and an solar cell designed for the laser frequency has an pretty nice coupling. 

[DDE]

  On 7/18/2020 at 3:25 PM, magnemoe said:

An laser and an solar cell designed for the laser frequency has an pretty nice coupling. 

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Should probably skip the heat-electricity-heat conversion and heat the propellant directly.

[IncongruousGoat]

  On 7/18/2020 at 3:25 PM, magnemoe said:

Yes, its 1000s, but they also need more than 10x ion trust to not get stuck in the radiation belt.

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For now, I think they're sticking to LEO (so, within the inner Van Allen belt). Good point for future LEO->MEO or LEO->GEO stuff though.