Green Propellant to Replace Hydrazine

[YNM]

30 minutes ago, kerbiloid said:

Two of three listed were serious military studies with a lot of experiments.

Edited July 13, 2018 by YNM

[RuBisCO]

YNM, 

Misinformation is Platinum: if you can say you have been doing [Y] for decades when you have really be doing [X] you have plausible deniability. So for example if you can say you been using [Y] for torpedo propellant then no one is going to question it unless they notice the torpedo has a speed and range that [Y] could not physically provide. So once again it is quite possible the military has had AF-M315E or equivalent for decades and no one noticed, perhaps not space proven, but working somewhere else. 

But then again there is infrastructure lock. Chlorine pentafloride never took off because it was too difficult and dangerous to handle, despite say Chlorine pentafloride/Hydrazine-Methanol would be 4% more ISP then N2O4/MMH, 25% more dense and 31% more ISP-density, that not enough improvement to warrant the danger of an oxidizer that burns through almost anything.  AF-M315E on the other hand 5% more ISP then hydrazine, 45% more dense and 53% more ISP-density without any serious complications, in fact less complications then hydrazine, heck I would not be surprised if AF-M315E could not be used in propellant cooled engines unlike hydrazine.   

[YNM]

47 minutes ago, RuBisCO said:

Misinformation is Platinum

Yup.

I'll just cross my fingers and wait.

Edited July 13, 2018 by YNM

[magnemoe]

12 hours ago, kerbiloid said:

Afaik, Apollo lands on it. Its RCS is between the cabin and the heatshield. 
Mercury and Gemini keep it under the chute box, outside of capsule.
Soyuz doesn't use. Afaik, it has a 30 kg peroxide barrel inside, right under a spaceman's head. It has it in a service module which doesn't land.
TKS VA jettisons the RCS after aerobraking and lands with no liquid fuel. FGB has ~4 t of hypergolics in tanks, and there are several tens kg in VA RCS.
About Orion and CST-100 not sure, probably like Apollo.
 Crewed Dragon (ta-dam!) is going to land on it. What a frightening idea. Either SpaceX doesn't know how dangerous are hypergolics, or they don't give a flag.

So, the retrorocketed capsules don't have hypergolics on landing.
Except Crew Dragon, which metaphysically looks like a 

  Reveal hidden contents

P.S.
It's nice at all: people are sure at once that hydrazine is an apocaliptic venom, and that Crew Dragon (lands with it) is a future new word in technics.

TY, and never said hydrazine was an apocaliptic venom, just that it was expensive to use as the danger increased the cost a lot. 
It would also be an problem with an powered dragon 2 landing. Know astronauts on an Apollo mission got sick as hydrazine was used or leaked after the capsule was open to atmosphere. 

[Xd the great]

Dragon capsule uses it as a escape system. So i suppose they can drain all fuel before landing.

[YNM]

1 hour ago, Xd the great said:

they can drain all fuel before landing.

... by using it in retropropulsive landing, which at least breaks down some of the 'nasty' stuff.

If they can just dump it, why bother with handling it carefully in the first place ? 

But we did widely use  asbestos anyway, so...

Edited July 14, 2018 by YNM

[Xd the great]

4 minutes ago, YNM said:

... by using it in retropropulsive landing, which at least breaks down some of the stuff

If they can just dump it, why bother with handling it carefully in the first place ? 

But we did widely use  asbestos anyway, so...

Because they do not want to mount solid rocket motors on a dragon capsule.

And I do not think they will use it for propulsive landing.

At least not without a parachute.

[RuBisCO]

Dragon will be outmodded anyways when BFS flies.  That is why they gave up on propulsive landing with Dragon, it was not worth the effort trying to get approval, and certainly the fact of N2O4 and MMH being so nasty toxic was part of why NASA did not approve. Sure maybe Dragon on AF-M315E might work safety wise, but SpaceX has no interest in mono-propellants and by the time a Dragon on AF-M315E would be flying BFR will already be operational, using  O2/CH4 for thrusters, take-off and landing. 

Fun Fact: there were some people crazy enough to propose mixing Liquid O2 and Liquid CH4 as a mono-propellant, turns out if you even shine a bright light on that mix it will explode. SpaceX will probably build O2/CH4 bi-propellant thrusts that are pressurized or electrically pumped and handle all attitude/maneuvering controls. 

[magnemoe]

3 hours ago, RuBisCO said:

Dragon will be outmodded anyways when BFS flies.  That is why they gave up on propulsive landing with Dragon, it was not worth the effort trying to get approval, and certainly the fact of N2O4 and MMH being so nasty toxic was part of why NASA did not approve. Sure maybe Dragon on AF-M315E might work safety wise, but SpaceX has no interest in mono-propellants and by the time a Dragon on AF-M315E would be flying BFR will already be operational, using  O2/CH4 for thrusters, take-off and landing. 

Fun Fact: there were some people crazy enough to propose mixing Liquid O2 and Liquid CH4 as a mono-propellant, turns out if you even shine a bright light on that mix it will explode. SpaceX will probably build O2/CH4 bi-propellant thrusts that are pressurized or electrically pumped and handle all attitude/maneuvering controls. 

Yes, looks like trend goes towards using pressurized fuel and oxidizer for reaction control for spaceships. ULA centaur replacement is another. 
Satellites and probes still need storable monoprop 

[kerbiloid]

5 hours ago, magnemoe said:

Satellites and probes still need storable monoprop 

Not necessary monoprop. UDMH/NTO works, too. And has significantly greater ISP.

[Xd the great]

How about ion thrusters for altitude control.

[mikegarrison]

Just now, Xd the great said:

How about ion thrusters for altitude control.

Altitude control of what? There are all-electric satellites already.

https://rsdo.gsfc.nasa.gov/images/catalog/301406_RapidIII_4Page_Layout_A_REV_1_11.pdf

On 7/13/2018 at 5:35 AM, RuBisCO said:

One key to acceptance is flight heritage: showing that a green-fuel-powered spacecraft has flown in orbit — starting with a single flight — without failing. “That gives us the ability to point back and say, ‘Hey, we’ve been through everything it takes to get this thing manufactured, integrated, processed, launched and operational,’” McLean says. “Every single one of those [steps] is a huge hurdle to overcome technically.”

This is basically describing the "TRL" system.

[RuBisCO]

9 hours ago, mikegarrison said:

Altitude control of what? There are all-electric satellites already.

https://rsdo.gsfc.nasa.gov/images/catalog/301406_RapidIII_4Page_Layout_A_REV_1_11.pdf

This is basically describing the "TRL" system.

Yes well some satellites lack the power to run fly wheels and ion thrusters for attitude control. 

And yes the whole purpose of that launch is to have flight heritage to convince customers it is worthwhile. 

[YNM]

On 7/15/2018 at 11:15 AM, mikegarrison said:

Altitude control of what? There are all-electric satellites already.

New Horizons and Dawn comes to mind.

[magnemoe]

On 7/15/2018 at 6:01 AM, kerbiloid said:

Not necessary monoprop. UDMH/NTO works, too. And has significantly greater ISP.

True, however it require fuel and oxidizer making system larger and more complex. Are there many satellites using UDMH/NTO, imagine some huge spy satellites does. 

[ChrisDayVACCO]

On 7/13/2018 at 5:35 AM, RuBisCO said:

The main challenge for NASA and proponents of the green monopropellant fuel is to convince space mission planners that the alternative fuel and its thrusters, which have never flown in space, won’t fail. Hydrazine is well-understood, as are its effects on components.

 

Well, another green monopropellant, LMP-103S, is on orbit with 48 different 1 Newton thrusters on 12 propulsion systems.  They have worked well since the first use in space in 2010.  Here is a link for more information:

http://ecaps.space/hpgp-characteristics.php

Chris

[insert_name]

On 7/15/2018 at 11:00 PM, YNM said:

New Horizons and Dawn comes to mind.

neither of those are all electric, dawn has a hydrazine rcs, and there is no way that the rtgs for new horizons could provide enough power for an ion engine

[YNM]

6 hours ago, insert_name said:

neither of those are all electric, dawn has a hydrazine rcs, and there is no way that the rtgs for new horizons could provide enough power for an ion engine

Exactly the point, my dear friend.

Our other friend was mentioning about "all-electric satellites". Of course it's a bit difficult to justify that's all we need when you look on Dawn and New Horizons.

 

Back on the main topic however, I'm still waiting whether it's a true green or a green paint.

Edited August 16, 2018 by YNM

[wumpus]

14 hours ago, insert_name said:

neither of those are all electric, dawn has a hydrazine rcs, and there is no way that the rtgs for new horizons could provide enough power for an ion engine

Try one of these: https://www.space.com/21867-cubesat-deep-space-propulsion-kickstarter.html

That said, I doubt this would shave off much of the initial delta-v needed to go to Pluto, nor have the delta-v needed to slow down for gravitational capture.  My understanding is that scaling up ion thrusters is the problem.  I'd expect that they scale down fairly well.

[RuBisCO]

On 8/15/2018 at 7:07 PM, ChrisDayVACCO said:

Well, another green monopropellant, LMP-103S, is on orbit with 48 different 1 Newton thrusters on 12 propulsion systems.  They have worked well since the first use in space in 2010.  Here is a link for more information:

http://ecaps.space/hpgp-characteristics.php

Chris

Intresting, but AF-M315E seems to have better performance than LMP-103S at 12% higher ISP instead of 6%, and 45% greater density instead of 24% (over hydrazine).

[magnemoe]

On 8/16/2018 at 10:08 AM, YNM said:

Exactly the point, my dear friend.

Our other friend was mentioning about "all-electric satellites". Of course it's a bit difficult to justify that's all we need when you look on Dawn and New Horizons.

Back on the main topic however, I'm still waiting whether it's a true green or a green paint.

 Main reason is not environmental but rater cheaper handling, this is more important on an cheap satellite, you might not even allow hydrazine on an secondary payload. 
Also the handling cost would be much the same  independent on how much fuel you need. 
Ion is better but has very low trust so not usable for circulation burn or orbital changes even if very nice for position keeping.

[wumpus]

2 hours ago, magnemoe said:

 Main reason is not environmental but rater cheaper handling, this is more important on an cheap satellite, you might not even allow hydrazine on an secondary payload. 
Also the handling cost would be much the same  independent on how much fuel you need. 
Ion is better but has very low trust so not usable for circulation burn or orbital changes even if very nice for position keeping.

I'm sure there are plenty of chemicals that are "more green" than hyrdazine that you wouldn't want in your garage/shed, but that could be tolerated on a secondary payload or wouldn't require technicians to suit up in hazardous materials outfits adding a million dollars or so to the budget, entirely thanks to the hydrazine.

Ions not useful for "orbital changes"?  I guess it entirely depends on the timeframe.  I'd assume that ions are ideal for "orbital changes" (especially inclination changes and or migrations to something like GTO).  On the other hand, if it is a "hot spare" for something like Iridium, you may be better off launching a new one in it's place (and have to have it scheduled to launch some months later) than have to wait for an ion engine to get it in position.  Also, considering the cost of most GTO satellites, operators want them online within days of launch, not months.  But anyone with a much smaller budget, any type of high-Isp electric propulsion will beat chemical.

[Racescort666]

There's also this: http://www.rocket.com/article/geostar-3-mission-success-enabled-aerojet-rocketdyne-xr-5-hall-thruster-system Looking back on that mission, it was a shared flight between Al Yah 3 and SES-14, both of which have electric propulsion and were able to get to their intended orbits. This was the Ariane 5 launch that they lost contact with after launch and it put both payloads into a 20ish degree orbit rather than the 3 degree typical of Ariane 5 launches.