Ram Booster

this is a nasa project using 24 ram jets as a first stage and than other off the shelf boosters to get various things to space in a quick way.

it claims to get sats and military craft to LEO for a very low cost.


this sounds like water downed TSTO system

technology.nasa.gov...

a reply to: penroc3

The first stage are 18 F-100-229 turbofans. And that thing is supposed to start vertically. Crazy stuff.

a reply to: moebius

it would be an interesting take off or would it be a launch

originally posted by: penroc3
this is a nasa project using 24 ram jets as a first stage and than other off the shelf boosters to get various things to space in a quick way.

it claims to get sats and military craft to LEO for a very low cost.


this sounds like water downed TSTO system

technology.nasa.gov...

Yup. This looks like yet another amateurish attempt by the airplane engineers at Armstrong to try to be relevant to the space launch problem.

For those who may not have read the article, it's actually a 3 stage system. The first 2 stages consist of a low-bypass turbofan powered stage, followed by a pure ramjet stage, followed by a pure rocket powered third stage. The 2 air breathing stages only get the third stage to about 30 km altitude and 1.2 km/sec velocity. The delta-V to get to low Earth orbit is about 8 km/sec, taking into account gravity losses, air drag, and whatnot. That means the third stage still has to supply about 6.8 km/sec of delta-V. That means the third stage still has to be almost a single stage to orbit rocket vehicle. That's why they had to assume a LOX-H2 upper stage--with "characteristics of the Centaur III".

The Centaur III is probably the most expensive upper stage in the US inventory.

They claim that a selling point is the fact that the first two stages use only Kerosene, thus avoiding the need for "hazardous cryogenic propellants"and "complex reaction control systems". However, the third stage consists of exactly those kinds of technologies. So, they're avoiding certain technologies in the first two stages because they're "bad", but using them in the third stage because they're "good". They're confused.

Of course, there have been numerous two-stage Earth-to-orbit system concepts designed that use an air breathing first stage, or perhaps an air breathing/rocket propulsion hybrid approach, and they would seem to provide a much more optimal launch system. For example, there is the Boeing approach patented in 1986:

patents.google.com...

Instead of separate turbojet and ramjet stages, this approach uses turbo ramjet engines in a single stage to accomplish about what this NASA approach takes two stages to accomplish.

And of course, two stage to orbit designs tend to converge on minimum mass solutions when the split in delta-V between the upper stage and the first stage is closer to 50-50 (about 4 km/sec, each). This is why it could make sense to add rocket propulsion to the first stage to get the separation velocity up higher. That would probably allow the use of LOX-Kerosene in the upper stage, instead of the more expensive LOX-H2.

And finally, there's cost. SpaceX is already down to about $2500/lb and set to go lower. The NASA article presented no cost analysis of their concept, but it requires developing 3 new stages, and landing one of them in the water (which probably renders it effectively expendable). I find it hard to believe that this would come out cheaper than SpaceX is already demonstrating.

All in all, this concept is about what I would expect from a High School science fair.

a reply to: 1947boomer

Could this be a way to move ram jet research, tech and money into the white world from some other project?

It doesn't look that way to me. The air breathing part of this idea proposes to make use of already existing turbofan and ramjet technology--perhaps including some material substitutions (such as ceramics)-- that has been unclassified for years if not decades. Nothing about this proposal screams advanced technology.

Although the article doesn't say exactly what prompted the engineers at Armstrong Flight Research Center to produce this concept, it looks to me like the standard kind of writeup that the field centers submit to NASA HQ in response to internal NASA calls for proposals. In other words, one of the major NASA enterprises (Aeronautics, in this case) decides that they want to spend money on some general area of study so they send out a call to the relevant center or centers with guidelines as to what level of effort they are looking for and what the terms of the study are. The centers then come back with proposed concepts and HQ decides which of them to fund and for how much. I suspect that that is what happened here.

a reply to: PhantomTwo

a reply to: 1947boomer

You have a PM, Sir. Check your inbox, please.

originally posted by: SpeedFanatic
a reply to: 1947boomer

You have a PM, Sir. Check your inbox, please.

Are you just PM'ing everyone who seems to know anything about anything and asking them to divulge classified information like you did to me?

Northrop just ground tested their solid rocket booster the other day.

There was a small explosion towards the end.

a reply to: Cavrecon22

do you have a video? maybe a drop in pressure at the end of the burn and made a 'popping' sound?


i know spaceX had a big oppsie recently as well

a reply to: Cavrecon22

The nozzle shattered.

a reply to: Zaphod58

originally posted by: penroc3
a reply to: Zaphod58

Thank you Zaph. I watched it live from our office and everything seemed like it was going fine until the end there. I wonder if it was a tolerance issue with the material?

Ooops...

originally posted by: Cavrecon22

originally posted by: penroc3
a reply to: Zaphod58

Thank you Zaph. I watched it live from our office and everything seemed like it was going fine until the end there. I wonder if it was a tolerance issue with the material?

I don’t have any inside information or anything, but it looks like the nozzle is obviously a composite/ceramic and not metallic. Probably Carbon-Carbon and/or Carbon-Phenolic. Composite materials like that are very sensitive to contamination or other variations in their material properties during layup. When they are subject to their operating temperatures and pressures, any little variation in properties causes internal stresses to build up locally. Because these kinds of materials are not ductile, it doesn’t take much in the way of unbalanced internal stresses to break them. The nozzle on solid motors is usually made out of the same stuff and experiences the highest heating rate. I wouldn’t be surprised if the failure started in the nozzle and propagated to the nozzle.

a reply to: 1947boomer

i bet it was a propellant issue, i think i posted a video explaining such a defect.


basically this is a larger version of the SRB's from the shuttle and granted it uses a different plasticizer(its super super close chemically) the size ming have caused an issue as far as pouring the solid propellant.


when the hot and liquid propellant it might have dried wrong and lead to bubbles or other defects in the propellant and caused uneven burning and causing parts of the unburnt propellant to go flying at high speed out the nozzle and if it hit and ricochet it could cause the failure we saw

originally posted by: penroc3
a reply to: 1947boomer

i bet it was a propellant issue, i think i posted a video explaining such a defect.


basically this is a larger version of the SRB's from the shuttle and granted it uses a different plasticizer(its super super close chemically) the size ming have caused an issue as far as pouring the solid propellant.


when the hot and liquid propellant it might have dried wrong and lead to bubbles or other defects in the propellant and caused uneven burning and causing parts of the unburnt propellant to go flying at high speed out the nozzle and if it hit and ricochet it could cause the failure we saw

Yes, of course that can happen, but they normally x-ray the propellant grain after they cast it in order to catch defects like that. That was standard practice on the Shuttle SRBs and I would be very surprised if they didn't do that for this motor. If they do detect a void in the propellant grain, they drill a hole down to it and inject additional propellant to fill the void and the hole they drilled. Those kinds of defects are fairly easy to detect and repair.

a reply to: 1947boomer

one would hope they did that simple check

but there is the new plasticizer so that might have had something to do with cohesin of the chemicals or not bonding right and created some situation that caused a chunk or mass of propellant to break free.

there is no doubt that whatever caused it was sudden and violent and i find that strange when most of the test was over(to the point they actually considered it a success).

well find out, at some point.