Green Propellant

Aerojet Rocketdyne has successfully tested a green propellant called AF-M315E and someday may be a substitution for hydrazine in spacecraft. Wikipedia describes this chemical as hydroxylammonium nitrate NH3OHNO3, which is an ionic liquid.

https://www.bizjournals.com/sacrame...t-rocketdyne-green-spacecraft-propulsion.html

Excellent, it will be great to see commercial rockets with different colored flames! I wanna see the Soyuz with a central skidmark and smokies in the boosters!

The news release is not well written. AF-M315E monopropellant is less toxic and have a higher density specific impulse than Hydrazine when used as a monopropellant. Like hydrazine it has a low vapor pressure so it still needs pressuring gas. As a monopropellant it is classified as a 1.3C low explosive.

https://www.rocket.com/files/aerojet/documents/Capabilities/PDFs/GPIM AF-M315E Propulsion System.pdf is a technical article on the propulsion system.

But the exhaust plume is not green.

Bob

bobkrech said:

But the exhaust plume is not green.

Bob

Click to expand...

I know.... but it would be nice!

The basics that i did pick up from the article. Less propellant needed, and less toxic in creation, and when burning/burnt. All this is a real step forward. If we need rockets, we should at least curtail the amount of damage done to us and the atmosphere.

Monopropellants are used virtually exclusively in maneuvering jets on a spacecraft... not for propulsion per-se... so atmospheric contamination doesn't seem like much of a worry (other than tanking/detanking operations and ground handling, which is a separate issue).

I guess from that standpoint and maybe a manufacturing standpoint it might be better, but otherwise it's hard to see a big advantage...

Later! OL JR

PS... poor wording on the thread title...

I think what they are saying that for steering jets that HAN is less toxic than the monopropellant hydrazine, but has a higher specific impulse and higher density. Obviously, the experience base is not there. I heard people talking about HAN more than 20 years ago. I look at the available oxygen balance and it seems that it could be used as an oxidizer in a bi-propellant system, but there has been very little interest to do so. The empirical formula looks amazingly like ammonium nitrate, but it has more oxygen. I am wondering what is the chemical reaction to make HAN. I remember some people talking about gels as propellants. I wonder if HAN was one of them.

I think CTI should match this breakthrough with a nice thumb in the air and change their solid booster formula to have one of our special effects formulas (Skid, etc)

>> The empirical formula looks amazingly like ammonium nitrate, but it has more oxygen. I am wondering what is the chemical reaction to make HAN.

aerostadt,

[H3N-OH]+ NO3-

Julius Tafel discovered that hydroxlamine hydrochloride or sulfate salts can be produced by electrolytic reduction of nitric acid with HCl or H2SO4 respectively:[8][9]
HNO3 + 3H2 → NH2OH + 2H2O https://en.wikipedia.org/wiki/Hydroxylamine#Production

My guess: treat NH2OH with HCl--> [H3N-OH]+ + Cl-

Then treating the salt with Ag+ + NO3- (aqueous) would precipitate AgCl and leave hydroxylammonium nitrate [NH3OH]+ + NO3- in solution.

The last two lines are high-school chemistry speculations and should be taken as no more.

cecil said:

>> The empirical formula looks amazingly like ammonium nitrate, but it has more oxygen. I am wondering what is the chemical reaction to make HAN.

aerostadt,

[H3N-OH]+ NO3-

Julius Tafel discovered that hydroxlamine hydrochloride or sulfate salts can be produced by electrolytic reduction of nitric acid with HCl or H2SO4 respectively:[8][9]
HNO3 + 3H2 → NH2OH + 2H2O https://en.wikipedia.org/wiki/Hydroxylamine#Production

My guess: treat NH2OH with HCl--> [H3N-OH]+ + Cl-

Then treating the salt with Ag+ + NO3- (aqueous) would precipitate AgCl and leave hydroxylammonium nitrate [NH3OH]+ + NO3- in solution.

The last two lines are high-school chemistry speculations and should be taken as no more.

Click to expand...

Interesting chemistry; it looks more complicated than simple ammonium nitrate.