[AR] Re: Size question
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Thu, 2 Jun 2016 00:35:47 -0400 (EDT)
On Tue, 31 May 2016, John Dom wrote:
I never knew Juno II was hiding a spinning top stage hidden under it's
shroud. With Jupiter C the top stages could be seen spinning wildly on the
platform before launch...
Yes, between (I think) higher aero loads and the desire to launch
unstreamlined satellites, they decided they needed a protective fairing.
Juno II would be better known if it hadn't been so short-lived. It was
more or less an improvised rocket, thrown together from stuff that WvB and
his crew already had on hand. But it inherited the poor reliability of
the Jupiter-C upper-stage cluster, and its performance wasn't impressive
compared to other rockets that were already in the pipeline.
(So WvB and crew skipped past modest evolutionary steps -- Juno III and IV
were paper designs only -- and started pushing Juno V, a massive rocket
which ended up with eight engines in the first stage and a new name, and
was in turn utterly dwarfed by its enormous successor...)
Never heard of Lambda 4S, the Japanese launcher...
It too was pretty obscure, outside Japan. It was retired immediately
after its only successful flight, since all it was really good for was
putting a very small satellite into orbit as a demonstration that Japan
could do it. The Mu series that succeeded it was more capable, and was
the mainstay of Japan's space-science program for a long time -- mostly in
LEO, but the Mu 3S-II did launch Japan's Halley's-Comet probes, which is
why I mentioned it as a candidate for the smallest-launch-to-escape title.
(The more recent M-V is really an entirely different rocket, despite some
nominal heritage from the Mu family.)
Size reminds me of a US Scout with fins.
Looks can be deceiving -- not only are the Mu's somewhat longer, but
they're much heavier. The Mu 3S-II gross takeoff mass was almost three
times that of a Scout.
(b) or the future
Hard to call. There is a lot of interest right now in (LEO) launchers
with very small payloads. It remains to be seen whether there is enough
market there to support a few of them even through development, never mind
operational service. (Most of today's cubesats are impoverished student
projects which can't afford commercial launch services; they *want* to fly
as secondary payloads on rockets mostly paid for by others.)
The experience from the last big commercial-small-launcher push isn't
encouraging. Athena is long gone, and several of its would-be competitors
never even made it to space. Pegasus and Taurus fly so seldom that it's
debatable whether they're really operational any more; Taurus's recent
failures may have been partly due to the difficulty of keeping launch
crews trained when they so rarely launch anything. And the latecomer,
Falcon 1, is also gone and was a total dead-end financial disaster...
except that it established SpaceX's rocket technology -- and equally
important, the company's credibility -- well enough to get Falcon 9 funded
and flying.
Will things be different this time? Wait and see...
Henry
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