What is rocket exhaust formed of?

[Spaceman17]

they are made of heat gases

so you can use for kill kerbals or throw thing to kill kerbals

[nobodyhasthis2]

Scott did a good explanation. From the basics right up to complex fuel mixtures that produce toxic waste.

 

[sevenperforce]

You can vary the O/F ratio in-flight to start with high thrust and then transition to lower thrust with higher specific impulse. That's how the Saturn V rocket was able to lift so much more payload (rovers, etc.) with the later Apollo missions; they adjusted the mixture ratio of the engines across the course of the flight to maximize thrust at liftoff and then increase specific impulse over time.

So "what's in rocket exhaust" will vary from "reaction products plus excess oxidizer" to "reaction products plus excess fuel" over the course of a burn, at varying ratios.

[NSEP]

Just going to say here that water from the exhaust gas of a rocket engine is not that drinkable. If you drink pure water as a source for hydration your body will digest itself. Its like having a plate as a meal. You need to add minerals to it cuz your water might be a bit 'super-distilled'.

[mikegarrison]

8 hours ago, NSEP said:

Just going to say here that water from the exhaust gas of a rocket engine is not that drinkable. If you drink pure water as a source for hydration your body will digest itself. Its like having a plate as a meal. You need to add minerals to it cuz your water might be a bit 'super-distilled'.

This definitely overstates any health risks of drinking pure water. Distilled water is safe to drink. It's just that your body does lose minerals naturally and you do need to replace them, and if you drink distilled (or otherwise pure) water then you aren't getting the replacement minerals from the water you drink. So you would need another source.

A bigger issue for drinking water that comes from rocket exhaust is that rocket exhaust, by its nature, is flung away from your rocket at very high velocity. So there is no way to drink it. If you could somehow capture it, then it would no longer be a rocket! But water from hydrogen/oxygen fuel cells is quite drinkable, unless some other part of the fuel cell (the membranes maybe) leaves toxins in the water.

Edited August 15, 2017 by mikegarrison

[wumpus]

7 hours ago, mikegarrison said:

This definitely overstates any health risks of drinking pure water. Distilled water is safe to drink. It's just that your body does lose minerals naturally and you do need to replace them, and if you drink distilled (or otherwise pure) water then you aren't getting the replacement minerals from the water you drink. So you would need another source.

I'd expect that you can drink distilled water all through a shuttle-length mission (but you never would because you would be carrying drinking water and won't bother with scavenging spent exhaust or similar).  A flight to Mars (and surface stay) would be a completely different matter and expect to use reverse-osmosis and distilling (the RO filters I've seen only filter half the water at most, cascading them only would go so far), and presumably add whatever minerals you would expect after all that.

[sevenperforce]

Distilled water is just fine to drink, though in the long run it can deplete the minerals in your body.

Deionized water, on the other hand, is much less safe. In small quantities it is fine, but if you drink enough of it, you can end up dehydrating yourself because the semimpermeable membranes in your cells will leak water in an attempt to equalize the ionic balance.

[Brotoro]

Didn't the astronauts drink water made by the fuel cells on Apollo flights (in the Command Module, anyway)? Wouldn't that have been pure water?

[DerekL1963]

26 minutes ago, Brotoro said:

Didn't the astronauts drink water made by the fuel cells on Apollo flights (in the Command Module, anyway)? Wouldn't that have been pure water?

Yes, and they suffered no ill effects from it.  And sailors (at least in the USN) drink nothing but distilled water for months on end (and have for decades), and suffer no ill effects from it.   The dangers are greatly overstated.

[Brotoro]

10 minutes ago, DerekL1963 said:

Yes, and they suffered no ill effects from it.  And sailors (at least in the USN) drink nothing but distilled water for months on end (and have for decades), and suffer no ill effects from it.   The dangers are greatly overstated.

I think that the Apollo 15 crew suffered from heart arythmia from lack of potassium, but I don't know if that was exacerbated by drinking distilled water. This was corrected on later Apollo missions with potassium supplements added to their Tang (or whatever).

[Vanamonde]

Unless people are drinking rocket exhaust, this has gotten rather off-topic. 

[kerbiloid]

Spoiler

Unless Moon dwellers use a launch tube to catch and reuse the rocket exhaust. This would save a lot of hydrogen and nitrogen, btw.

 

[Grand Ship Builder]

We've gone pretty off topic then 

[Phineas Freak]

Using Rocket Propulsion Analysis to get information about the nozzle exhaust products of three different engines:

• RD-170 (RG-1 & LOX)
• RD-253 (UDMH and NTO)
• RS-25   (LH2 & LOX)

RD-170:

Spoiler

• CO         (Carbon Monoxide)
• CO2       (Carbon Dioxide)
• COOH    (Carboxylic Acid)
• H            (Monoatomic Hydrogen)
• H2          (Diatomic Hydrogen)
• H20        (Water)
• H2O2     (Hydrogen Peroxide)
• HCHO    (Formaldehyde)
• HCO       (Bicarbonate)
• HCOOH (Formic Acid)
• HO2       (Hydroperoxyl)
• O            (Monoatomic Oxygen)
• O2          (Diatomic Oxygen)
• OH         (Hydroxide)

RD-253:

Spoiler

• CO        (Carbon Monoxide)
• CO2      (Carbon Dioxide)
• COOH   (Carboxylic Acid)
• H           (Monoatomic Hydrogen)
• H2         (Diatomic Hydrogen)
• HO2      (Hydroperoxyl)
• N2         (Nitrogen)
• NH3      (Ammonia)
• NO        (Nitric Oxide)
• O           (Monoatomic Oxygen)
• O2         (Diatomic Oxygen)
• OH        (Hydroxide)

RS-25:

Spoiler

• H           (Monoatomic Hydrogen)
• H2         (Diatomic Hydrogen)
• H2O      (Water)
• H2O2    (Hydrogen Peroxide)
• HO2      (Hydroperoxyl)
• O           (Monoatomic Oxygen)
• O2         (Diatomic Oxygen)
• OH        (Hydroxide)

RD-170 RPA analysis file link

RD-253 RPA analysis file link

RS-25 RPA analysis file link

Edited February 14, 2019 by Phineas Freak
Remove file links

[Grand Ship Builder]

5 minutes ago, Phineas Freak said:

Using Rocket Propulsion Analysis to get information about the nozzle exhaust products of three different engines:

• RD-170 (RG-1 & LOX)

Don't you mean RP-1, not RG-1?

[Phineas Freak]

@Grand Ship Builder No, i mean RG-1. RP-1 and RG-1 can be considered the same but there are some subtle differences (mostly in their densities, RP-1: 0.81 g/ml - RG-1: 0.83 g/ml) that they set them apart.

Practically, they are the same. The RD-180 for example (an RD-170 derivative) uses RP-1 on the Atlas V CCB but it is built using the RG-1 stats.

TL;DR: RP-1 for the American kerolox engines, RG-1 for the Russian.

Edited August 17, 2017 by Phineas Freak

[Grand Ship Builder]

11 minutes ago, Phineas Freak said:

@Grand Ship Builder No, i mean RG-1. RP-1 and RG-1 can be considered the same but there are some subtle differences (mostly in their densities, RP-1: 0.81 g/ml - RG-1: 0.83 g/ml) that they set them apart.

Practically, they are the same. The RD-180 for example (an RD-170 derivative) uses RP-1 on the Atlas V CCB but it is built using the RG-1 stats.

TL;DR: RP-1 for the American kerolox engines, RG-1 for the Russian.

oh, mkay.

 

 

i'll just walk away slowly, then.