Bundles of rockets - what about it?

According to their German-only report http://www.tim-report.de/Project_Enterprise.pdf the Talis Institute is thinking about using their microsat-oriented rocket "Enterprise" for manned suborbital flights too.

What are comparisons of rocket-bundles to one whole rocket resulting in technically and technologically? Are they dangerous, suboptimal etc. or are they reasonable? ...

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Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

They're suboptimal (because you have a higher dry weight due to more equipment), and they're less dangerous (because there's less of a chance that the entire thing will blow up).

The big problem with a bundle is getting them all to light at almost exactly the same time -- a very fancy trick, and one that is rarely pulled off without a hitch. Bundles are generally seen as overcomplicated, although somewhat safer than a single rocket.

I tend to think of a bundled system as far more dangerous. Any time you add to the complexity of a system the possibility of failure increases. (For instance, though the Shuttle SRB's have a good track record, as far as boosters go, it only took one to take down the entire STS stack). As Spacecowboy mentioned, it increases mass as well.

I suppose I am thinking of a "Bundle" as many engines, as upposed to a multi-engine system such as the S-V's first stage or STS's multiple SSMEs. I have a feeling, when all is said and done, that the D-IV might get the nod for Project Constellation because it doesn't rely on bundled solid boosters.

Better, and cheaper in the long run, to use a big-dumb booster, but I guess if you've already got the small rocket, and you can't afford to develop something new from scratch, the bundling option is enticing. To me it's a desperation move.

That's for sure. I still remember launching a 4 engine cluster model rocket. The rocket took off before all the engines ignited, pulling the igniter out of some of the engines. As a result there was not enough power to take the rocket high enough and the parachute deployed too late. Crash!

And the sad thing is that the Estes rocket ignition system is not much worse, reliability-wise, than the systems used by orbital launch vehicles.

To detail my initial question by a question I should have asked before the initial one - would the use of a microsat-orineted rocket for suborbital passenger flight require a modification to be able to bundle such rockets or can bundles avoided by alternative modifications?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

There woulld have to be modifications. You can't just strap them together and bolt a crew cabin on the top. It's a completely new vehicle at that point.

Okay - but is it possible to modify a microsat-oriented rocket in a manner that bundling of them isn't required or would that end up with a completely new rocket which cannot be considered to be a modification of a microsat-rocket any longer but would be a complete new rocket merely?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

I don't know of any active launchers that I would call "microsat" launchers at the moment, though there are very small launchers.

Many of these accelerate very quickly. It might be fun, up to a point (it's not fun when you pass out)

Now, take the Pegasus. It's only 1.2M in diameter. Anything you put atop it is going to bulge out quite a bit which may or may not be a problem. (see Atlas V). But at some point, the CG is going to become interesting

The Pegasus only launches very small payloads, it doesn't need to be very wide - and the Atlas generally only uses the wider fairing in missions where it is also using solid rocket boosters, to allow it to launch larger weights. You can put a wider fairing on, but it's prefered not to.

I know. Ekkehard was hypthesizing, I think, about putting a manned capsule on a microsat launcher. Pegasus was the smallest one I could think of at the moment.

Scout was smaller. Their may be a few other smaller ones that I am not aware of, besides vaporware.

How about the Jupiter-C?
http://en.wikipedia.org/wiki/Jupiter-C_%28rocket%29
It used several stages, some of which were clusters of small solid rocket motors. The payload would be smaller than a person though, much less a person plus space craft.

(EDIT) The Vanguard rocket was pretty small too.
http://en.wikipedia.org/wiki/Vanguard_rocket

Well I was thinking of ones that currently exist.

Hello, bad_astra,

I haven't been hypothesizing - Talis is in fact speaking of offering suborbital flights by capsule on top of their microsat-rocket. They are speaking of doing it by a modified version of their "Enterprise"-rocket.

This caused my questions and this thread.

Concerning the microsat-rocket currently under development they are mentioning the large market for such rockets in the nearby future. So they expect to have very much launches of that rocket. It's semi-reusable. They will NOT have that number of launches at the suborbital market in the same nearby fiuture I suppose. Because of this my first thought was that they might think of modify "Enterprise for bundling to be able to launche a manned capsule or vehicle.

Al this and perhaps more I want to stress here.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

Just to add a detail - the modified version of Enterprise for suborbital flight will be single-staged if they realy do that modification.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)