ARCA Plans 2018 Launch For Revolutionary Single-Stage Rocket (newatlas.com)

An aerospace company is building a cheap, simple, lightweight rocket that they hope will redefine the microsatellite industry. Eloking quotes New Atlas: New Mexico-based ARCA Space Corporation has announced that it is developing the world's first Single Stage to Orbit (SSTO) launch vehicle that can deliver both a small payload and itself into low Earth orbit, at a cost of about US$1 million per launch. Dubbed the Haas 2CA after the 16th century rocket pioneer Conrad Haas, the new booster uses a linear aerospike engine instead of conventional bell-shaped rocket engines to do away with multiple stages. [YouTube video]
They're working with six different NASA centers and have scheduled their first launch for 2018. The rocket will be 53 feet tall (16 meters) with a diameter of just 4.95 feet (1.5 meters), and will weigh 1,210 pounds when empty, but 35,887 pounds when fueled, "thanks to ACRA's proprietary composite materials for the propellant tanks and other components."

Comments

Revolutionary Rocket aka aerospike engine

[Eloking]

I remember back in the early 2000 when I first read about the aerospike engine and saw that stunning picture : https://upload.wikimedia.org/w...

Quite an impressing concept, the nozzle compensate depending on the altitude to kept it's efficiency on a wide range of altitude. One of the reason of multistage rocket is, of course, to lower the weight to raise efficiency as you climb, but another more subtle reason is also that conventional bell-shaped rocket are only efficient at a narrow range of altitude.

Aerospike engine doesn't have this problem, it stay efficient at all time. And on the plus side, as you can see in the picture above, they look freaking cool.

Re:Revolutionary Rocket aka aerospike engine

[Anonymous Coward]

Aerospikes are really awesome, but they tend to be heavy and difficult to cool. In this case, one property trades off with the other. If you lighten it up, the tip of the spike gets very thin and harder to cool. If you want to cool it more effectively, you have to widen it and make it heavier, and heavy engine designs are exactly the opposite of what you want with a SSTO design.
That video, like pretty much any material I've read on SABRE/Skylon, registered substantially on my BS-meter. If they have developed solutions to create an aerospike that they know will be light enough for a SSTO application, then they've made some substantial breakthroughs that I haven't heard about. If they're just saying "let's take a fresh look at the aerospike design and ditch the wings and landing gear this time", then great, but it's a bit premature to claim that they're going to re-re-revolutionize the launch industry. NASA was trying really hard to do that the first time around.
My questions: How and where does ARCA intend to solve the weight problems? The video says they'll use composites. Rockets already use composites. There has always existed an extreme incentive for weight reduction in the space industry since its inception. What's ARCA's advantage? Saying "simpler design, better materials" is just hand-waving.
If their only advantage is the extra efficiency of the aerospike, then I'm betting against them.

Re:Revolutionary Rocket aka aerospike engine

[AJWM]

You're confusing aero spike engines with simpler (but heavier) spike engines.

In an aerospike, aerodynamic forces (often with the assist of gasses injected at the base of the engine) form the "pointy" part of the spike, so there's both the lighter and easier to cool aspect. Also known as a plug-nozzle, but the latter are usually (a) circular and (b) even shallower than this linear aerospike.

Spike nozzles (circular ones) have also been flight tested, but yeah, the tail of that spike is heavy -- and also not what you want if you're planning to reuse the vehicle, because it aggravates reentry heating. (Doesn't look like this is what ARCA is planning though, I guess they're just going for cheap and disposable. Maybe reusable will follow.)

NASA never had any problems with their X-33 aerospike, it was all down to the weird-ass V-shape fuel tank configuration.

Re:Well...

[Rei]

- Net propellant densities are very similar to many others, such as MON, IRFNA, etc.
- The others are non-cryogenic as well.
- No difference on staged combustion for the others

Versus:
  - Not self-pressurizing
  - Detonates if it gets too hot
  - Detonates if there's any contamination in the tank, the plumbing, fittings, anything. The cleanliness requirements can be extreme.
  - You can load it up with stabilizers to prevent explosion, but then they hinder combustion as well, as well as lowering performance.

It doesn't even win on a "health hazard" perspective, as one may think when they think of alternatives. HTP isn't like household peroxide - it burns your skin, your lungs, causes blindness if it gets in your eyes in tiny quantities, etc. You not only have to wear protective suits, but you have to make sure that they're made of a material that it won't explode on contact with. It's easier to clean up than some of its competitors, but that's about it.

Everyone tries it. Then subsequently gives up on it.