Asparagus-style rockets in the 1960's?!?!?!

[MaverickSawyer]

Look what I found on Encyclopedia Astronautica...

http://www.astronautix.com/craft/bonhicle.htm

The launcher is a 4-2-1 style Asparagus rocket, used for a direct-ascent flight to Mars. I think this might be a viable option for trips to Duna.

Thoughts?

[Tim_Barrett]

4-2-1 is an interesting design... I'm not sure how much fuel it would save over the tanks that are left they for longer, so I can't tell if it's actually more efficient or not.

[randyrules711]

Without actually even reading anything, I feel like Von Braun was behind this. He was a least a hundred years ahead of his time. As far as asparagus rockets go, I don't use them. Realistically, they are very risky. If a fuel tank runs out before planned, it could shut off an engine and throw the entire rocket off balance. You would need a very reliable method of rationing fuel on time to make it work correctly every time.

[softweir]

Very interesting!

Actually, it was a gentleman by the name of Philip Bono who proposed this while working at Boeing. It wouldn't have worked - his data on Mars' atmosphere was limited and severely incorrect, and the glider lander he proposed would have been unable to land.

I'm taking the liberty of moving this to the new Off-Topic/The Science Labs section where it properly belongs. It isn't really about KSP!

[MaverickSawyer]

Not where I had indended the thread to head, discuttionwise, but since it's headed this way, great idea.

As for the whole 4-2-1 staging, Conestoga used a similar setup with Castor SRMs, firing four, then two, then one, and then a Star-37 or -48 motor. I've tried to make it in KSP, but no luck yet... Soilds don't have thrust vector in KSP, which makes life VERY tough.

[DAL59]

@nyrath Wrote an article on this.  

http://www.projectrho.com/public_html/rocket/realdesigns.php#id--Bono_Mars_Glider

[Mad Rocket Scientist]

Some iffy aerodynamics going on there.

"Unfortunately for Bono's design, it was crafted with the assumption that Martian surface air pressure was 8% of Terra. We now know that it is less than 1%"

Ah, there we go. It still looks cool though. Maybe it would work in KSP.

[MaverickSawyer]

Man, talk about a blast from the past. 

 

In all seriousness, though, the Bono glider would work quite well on Duna, wouldn't it? After all, isn't Duna's atmosphere something like 20% of Kerbin datum pressure?

[wumpus]

Some notes on asparagus staging (yes, it's a necrothread and I'm going back to the topic.  But mostly on the differences between 2012 and 2018).

Asparagus staging dates from at least 1953 if not 1947 (I found it described in the 1958 work "Space Flight" by Carsbie C. Adams) even if it wasn't named "Asparagus" until 1989.

One important thing to understand is that the cult of Asparagus made a lot of sense in pre-release KSP, not so much in "real life", "post-release KSP" and "realism overhaul".  The biggest reasons follow:

The biggest reason for asparagus staging was that KSP had a limited maximum size of rocket engines.  If you wanted a bigger rocket and/or more delta-v, you simply piled small engines on top of small engines and built "kerbal" rockets.  Only N-1 and Falcon Heavy use "lots" of engines, and really doesn't work in real life.  More modern KSP (including beta and other late pre-release editions) had things like mammoths, twin-boars that made these "kerbal" rockets only needed for wackjob-style rockets built out of huge numbers of mammoths.

Second is that for peak aero efficiency, you need to maintain a velocity equal to your terminal velocity.  In KSP<1.0, this was achieved by limiting TWR=2.0.  In real life (and KSP>=1.0) this requires a huge TWR and essentially requires solid boosters.  Asparagus staging let TWR stay relatively constant (at ~2.0) all the way through the souposphere.

In pre-release KSP, vacuum nozzles had full thrust but simply used more fuel to compensate.  I didn't understand why this was so terrible until some of my "lift off with vacuum rockets" simply failed and showed just how badly I was "cheating" by relying on old KSP's poor physics model.  Consider a hypothetical Falcon 9 with "onion staging" ("onion staging" is provably less efficient than asparagus staging, but is needed to make my point): Instead of 9 first stage engines + 1 second stage engine, this "Falcon 8" rocket has 8 first stage engines firing in parallel (and feeding through KSP's "magic fuel lines") the second stage engine.  There is no way the benefit of losing one engine (roughly one ton) will compensate for using a sea level optimized nozzle on the second stage (which provides much more than half of the delta-v).

Also post-release KSP has a working aero model.  The cult of Asparagus fed on the issue that strapping stage after stage in parallel didn't add any aero losses.  I think this is mostly minor, but it still artificially made asparagus look good.

That said, asparagus would really help on Falcon Heavy, but was beyond even spacex's prowess (and remember all the claims that it was impossible to stabilize all 27 engines in Falcon Heavy.  SpaceX does 6 impossible things before breakfast and was stuck on this one detail).  Drop tanks may be catching up and replacing asparagus as "important kerbal tricks" in post-release KSP, and can be seen in Rocket Labs' Electron (in the form of "drop batteries", which makes sense since they don't get any lighter and are an obvious candidate to drop).  I'd expect that restartable vacuum optimized craft would try drop tanks in the future (do one Pe kick on one tank, shut down, drop the first tank, switch to the second tank, and do the second (final?) Pe burn afterwards).

[kerbiloid]

But should we call Asparagus any design with multiple engines, rather than dropping modules one by one?

Then UR-700 and OTRAG are two asparaguses ever implemented in metal (as a test mockup and a real rocket correspondingly).

Edited September 27, 2018 by kerbiloid

[wumpus]

5 hours ago, kerbiloid said:

But should we call Asparagus any design with multiple engines, rather than dropping modules one by one?

Then UR-700 and OTRAG are two asparaguses ever implemented in metal (as a test mockup and a real rocket correspondingly).

Parallel staging started the space era, as most rocket designers didn't want to deal with the issues of serial staging and mid-air ignition (just look at a Soyuz, it is still used).  The key to Asparagus is to cross-feed fuel lines, especially where one fuel tank is jettisoned (whether or not including an engine) and another fuel tank is used by the remaining engine  (thus the Shuttle doesn't count.  It uses completely different engines (OMS) for orbital insertion after ditching the main fuel tank).

As a pressure-fed engine, it isn't clear that there would be any benefit for cross-feeding the OTRAG fuel tanks ("engine mass" shouldn't be all that high), nor was there any interest as reducing complexity appeared the overall goal.

I still think the closest we've seen is Rocket Labs dumping spent batteries, while the original motors continue using other batteries on flight.

Edited September 27, 2018 by wumpus
attacked once again by strikethrough bug

[kerbiloid]

10 minutes ago, wumpus said:

The key to Asparagus is to cross-feed fuel lines, especially where one fuel tank is jettisoned (whether or not including an engine) and another fuel tank is used by the remaining engin

That's about UR-700. It should have cross-fed blocks.

https://iaaa.org/current-work-in-progress-ur-700/

OTRAG didn't have, of course.

[wumpus]

2 hours ago, kerbiloid said:

That's about UR-700. It should have cross-fed blocks.

Weren't the universal rockets pushed by Glushko?  His specialty was engines, so he'd have to deal with all the critical issues of cross-feeding and asparagus in general.  I'm curious how far he got, but there doesn't seem to be any Soviet/Russia/former-USSR development of such things from his work.

And of course the universal rockets used hypergolics as a first stage fuel, which I oppose in principle (can't you even light the things when they are on the ground???).

[kerbiloid]

3 minutes ago, wumpus said:

Weren't the universal rockets pushed by Glushko?

UR series was Chelomei's toy, so afaik Glushko as his competitor did his best to promote his own design (Energy series) instead.
But Glushko's engines for UR-700 were almost ready and even tested, so probably the technical issues didn't scare him very much.

7 minutes ago, wumpus said:

And of course the universal rockets used hypergolics as a first stage fuel,

Originally it was going to use hypergolics at all stages.
But then the fluorine was suggested for the upper one, lol.

[DDE]

3 hours ago, kerbiloid said:

UR series was Chelomei's toy, so afaik Glushko as his competitor did his best to promote his own design (Energy series) instead.

@wumpus, the UR-700 and Energia did not exist concurrently. AFAIK Glushko inherited the N-1 and spent some time before killing it. But by then UR-700 was entirely dead, partly because the first-stage, oxidizer-rich full-flow staged combustion engine, RD-270, was having serious trouble. This meant a gap of six years between one project dying and the other being conceptualized.