Minimum Number of Rocket Designs

Suppose one wanted to trim the many different rocket designs
we have to the minimum useful few. We'd like to have a rocket
well suited to every task, but don't need to have multiple
designs for the same task.

The intent is to decrease cost by decreasing the total number of
designs and increasing the number of launches per design. I recognise
that the politics of this would be "difficult".

Would this list cover the tasks we ask of rockets?

Space Shuttle -- Humans to orbit

Delta VI Heavy -- Sat Launch -- 10,843 to GTO

Delta IV Med (5.2) -- Sat Launch -- 6,120 to GTO

Delta IV Med -- Sat Launch -- 3,900 kg to GTO

Delta IV Small-- Sat launch -- 2,200 kg to GTO

Pegasus XL -- Lite launch -- 443 kg to 185 km orbit

I chose the Space Shuttle over the Soyuz simply because the
Space Shuttle is more flexible. I chose the Delta IV family because
it seemed to cover the largest range in payload weights in a single
family of rockets.

The intent is to decrease cost by decreasing the total number of
designs and increasing the number of launches per design.

What reduces cost is competition. So I'd definitely try to keep at
least 2 rockets in each payload category. This is the premise behind
the EELV program (with Delta IV and Atlas 5 being the two
competitors).

Having said that, there is a glut of rockets relative to the number of
customers. This is mainly driven by each nation's desire to have
their own rather than buy abroad. Is this changing with the Starsem
deal to launch Soyuz from French Guyana, Sea Launch, Atlas 5's
licensing/purchase of a Russian engine, etc? Time will tell whether
globalized launch companies become the norm, or remain somewhat at the
margins of the industry.

I chose the Space Shuttle over the Soyuz simply because the
Space Shuttle is more flexible.

What's your goal? Cost or flexibility? I'm not sure even its
defenders would say that shuttle is likely to win on the former.

Jim Kingdon wrote in message ...
What reduces cost is competition.

Er... No. What reduces cost is a long stable relationship, it doesn't
necessary have to be with just ONE party, it can be with many parties.

Profiting from competition is essentially a 'divide and conquer'
tactic, it's fine, if one want to eliminate the enemies by making them
work for you by fighting each other.


Having said that, there is a glut of rockets relative to the number
of customers. This is mainly driven by each nation's desire to have
their own rather than buy abroad.

That's because having your own launcher is a national pride. Just like
the national currency. An easy way to reduce national pride is to
remove a national currency, a national launcher, a national monument
(like the statue of a leader), and so on.

Is this changing with the Starsem deal to launch Soyuz
from French Guyana, Sea Launch, Atlas 5's licensing/purchase
of a Russian engine, etc?

Er... Renting a place, hiring a launching company, buying engine
parts, and so on from foreign parties aren't damaging to one's pride,
provided it's done well.

Because not all countries or companies have the best launch sites,
engines, and so on. So they might rent or buy stuff from foreign
parties, like Shen Zhou which was based on Soyuz.

The problem is that many of these things weren't done to increase
national pride, but instead done with the intention to decrease the
national morale. And the mass media also make it look like national
pride has decreased due through these actions..

Time will tell whether globalized launch companies become the norm,
or remain somewhat at the margins of the industry.

"Globalism is Behind Marxist Subversion of America, War on Terrror"

http://www.savethemales.ca/010102.html

"Charles Talleyrand" wrote in message
...
Suppose one wanted to trim the many different rocket designs
we have to the minimum useful few. We'd like to have a rocket
well suited to every task, but don't need to have multiple
designs for the same task.

The intent is to decrease cost by decreasing the total number of
designs and increasing the number of launches per design. I recognise
that the politics of this would be "difficult".

Would this list cover the tasks we ask of rockets?

Space Shuttle -- Humans to orbit

Delta VI Heavy -- Sat Launch -- 10,843 to GTO

Delta IV Med (5.2) -- Sat Launch -- 6,120 to GTO

Delta IV Med -- Sat Launch -- 3,900 kg to GTO

Delta IV Small-- Sat launch -- 2,200 kg to GTO

Pegasus XL -- Lite launch -- 443 kg to 185 km orbit

I chose the Space Shuttle over the Soyuz simply because the
Space Shuttle is more flexible. I chose the Delta IV family because
it seemed to cover the largest range in payload weights in a single
family of rockets.


While I'm not totally sure about Delta IV Heavy vs. Atlas V Heavy, I do know
that the other Atlas V configurations (401 through 551) cover a better range
than the Delta IV family.

"The Ruzicka Family" wrote in message ...
I chose the Delta IV family because
it seemed to cover the largest range in payload weights in a single
family of rockets.


While I'm not totally sure about Delta IV Heavy vs. Atlas V Heavy, I do know
that the other Atlas V configurations (401 through 551) cover a better range
than the Delta IV family.

Delta IV is optimized for GTO missions. Atlas V, with
its higher thrust hydrocarbon first stage, has better
LEO-hauling ability than Delta IV - an important detail
when it comes to potential NASA use. Atlas V is also
proving to be commercially competitive while Delta IV
isn't even being offered for commercial launches. This
probably means that Atlas V is going to cost less than
Delta IV - another important detail for NASA to consider.

- Ed Kyle

"ed kyle" wrote in message
om...
"The Ruzicka Family" wrote in message
...
I chose the Delta IV family because
it seemed to cover the largest range in payload weights in a single
family of rockets.


While I'm not totally sure about Delta IV Heavy vs. Atlas V Heavy, I do
know
that the other Atlas V configurations (401 through 551) cover a better
range
than the Delta IV family.

Delta IV is optimized for GTO missions. Atlas V, with
its higher thrust hydrocarbon first stage, has better
LEO-hauling ability than Delta IV - an important detail
when it comes to potential NASA use. Atlas V is also
proving to be commercially competitive while Delta IV
isn't even being offered for commercial launches. This
probably means that Atlas V is going to cost less than
Delta IV - another important detail for NASA to consider.

- Ed Kyle


What do you mean by "optimized for GTO missions"? I'm truly not trying to
be argumentative here; I'm honestly curious. If you're saying that Delta IV
is somehow "better" for GTO missions than Atlas V, I'd really like to know
how. Obviously, there are a whole range of missions that can be classified
as "GTO", from the basic 100nm x 19,323nm orbit, to super-syncs, minimum
delta-v to GSO, descending-node vs. ascending node injections, etc. When
you compound things with a large range of spacecraft weights for GTO
missions, that's where I get confused as to what "optimized for GTO
missions" might mean.
I know that an Atlas V 401 has better performance to GTO than a Delta IV
with 2 strapons, so I guess you could say that the basic Delta IV, with no
strapons, is better suited to "smaller" GTO payloads than an Atlas IV 401.
Whether or not Atlas V will end up costing less than Delta IV, I have no
idea. A lot might be riding on the next EELV government buy.

P. Ruzicka

"The Ruzicka Family" wrote in message ...
"ed kyle" wrote in message
om...

Delta IV is optimized for GTO missions. ...


What do you mean by "optimized for GTO missions"?

Consider a straight up comparison of the two EELV base-models.
Delta IV was designed from the outset to boost smaller GTO
payloads (to standard GTO orbits from Cape Canaveral) than
Atlas V (4 versus 5 metric tons). But Delta IV loses even
more ground to Atlas V when it comes to LEO missions.
Delta IV-M can boost only 8.5 tons to a 185 km orbit while
Atlas V-401/402 can loft more than 12 tons. I think the
root cause of this is because both Delta IV stages produce
lower thrust than the Atlas stages (Atlas uses two Centaur
engines for LEO missions) so that Delta IV suffers higher
gravity losses. Delta IV would also have tighter liftoff
thrust-to-weight limitations than Atlas V.

- Ed Kyle

"ed kyle" wrote in message
om...
"The Ruzicka Family" wrote in message
...
"ed kyle" wrote in message
om...

Delta IV is optimized for GTO missions. ...


What do you mean by "optimized for GTO missions"?

Consider a straight up comparison of the two EELV base-models.
Delta IV was designed from the outset to boost smaller GTO
payloads (to standard GTO orbits from Cape Canaveral) than
Atlas V (4 versus 5 metric tons). But Delta IV loses even
more ground to Atlas V when it comes to LEO missions.
Delta IV-M can boost only 8.5 tons to a 185 km orbit while
Atlas V-401/402 can loft more than 12 tons. I think the
root cause of this is because both Delta IV stages produce
lower thrust than the Atlas stages (Atlas uses two Centaur
engines for LEO missions) so that Delta IV suffers higher
gravity losses. Delta IV would also have tighter liftoff
thrust-to-weight limitations than Atlas V.

- Ed Kyle

I see what your saying. However, in reality both launch vehicles were
originally designed from the outset specifically for launching the exact
same government payloads in the EELV program; the National Mission Model
(NUMB), I think it was called. Commercial payload considerations, at least
for Atlas VS., came later.

The first commercial mission the Atlas VS. looked at was Telexes; that was
the payload that drove the requirements for adding the solids later on. By
that time though, the Atlas VS. core was already designed, with the LOX feed
and avionics pod not opposite each other, as was the launch pad itself. No
one at Lockheed Martin initially considered the idea of one day adding
solids to the vehicle. That's why Atlas VS. ended up having up to 5 big
asymmetric solids, instead of 6 slightly smaller symmetric ones. It was too
late in the program to redesign the core and pad.

Anyway, since both Atlas VS. and Delta IV were originally designed to launch
the exact same payloads, one would think that they were designed for the
same performance range. I think were Delta IV stumbled, however, was when
their new core main engine ended up having lower thrust than they had
anticipated. That's probably a big part of the reason why the bare bones
Delta IV has less capability than a bare bones Atlas VS. 401.

I don't know as much about Delta IV, but I do know that Atlas VS. has some
good liftoff limitations as well, depending on the configuration. Those big
solids pack a pretty good punch! Too much of a good thing can rip the
bottoms of your tanks off if you're not careful!

UP. Ruzicka

"Charles Talleyrand" wrote in message ...
I chose the Space Shuttle over the Soyuz simply
because the Space Shuttle is more flexible.

Er... If it's flexible, then why is that it's the Soyuz that is
currently keeping the I.S.S. manned?

It should be noted that the R-7 family (used for Sputnik, Vostok,
Voskhod, Soyuz, Progress, Molniya, and so on) has been in service for
around more that four decades, and it has been used for many things,
both for manned applications and unmanned applications.

Anyway. If the minimum of rocket designs are only applied to the ones
used by U.S.A.'s space program, I don't think that the Soyuz is even
an option to cross out, since it belongs to the Russian space program
(and also the China space program). And if the minimum of rocket
designs are applied to the designs used by the whole world, what make
you so sure that the rest of the world would settle with only the
offers offered by companies that had their HQs at the U.S.A.?

As for the Space Transportation System, it's actually can be quite
flexible provided one eliminate its depency to the Orbiter's engines,
something like Energia is quite flexible since many types of payload
can be attach to it (the proposed Russian Mars design even had a
saucer attached to it). Though I don't know if I agree on it carrying
LOTS of liquid hydrogen, they should have just use hydrocarbon
(kerosene).


As for minizing on certain designs.

I don't know if one should minimize on certain current designs, but
there are certainly some needs for certain tasks.

Light, medium, and heavy manned crafts to L.E.O..

Light, medium, and heavy cargo crafts to L.E.O..

Light, medium, and heavy cargo crafts to G.S.O..

EAC wrote:

It should be noted that the R-7 family (used for Sputnik, Vostok,
Voskhod, Soyuz, Progress, Molniya, and so on) has been in service for
around more that four decades, and it has been used for many things,
both for manned applications and unmanned applications.


In fact, we are coming up on the 50th anniversary of the start of actual
construction work on the R-7 "Semyorka"; the program for its development
was approved way back in February of 1953.

Pat