Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO470.TXT

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Date: Sun, 29 Nov 92 05:06:54
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #470
To: Space Digest Readers
Precedence: bulk


Space Digest                Sun, 29 Nov 92       Volume 15 : Issue 470

Today's Topics:
         Chicago DC-10 (Was Re: Shuttle replacement) (2 msgs)
                            escape systems
                      Evil wicked flying bombs!
                            launch windows
            Military History (Was Re: Shuttle replacement)
  Not at Caltech? (was Re: NASA Daily News for 11/24/92 (Forwarded))
                           shuttle destruct
                     Shuttle replacement (8 msgs)
                    What comes after DC-1 (3 msgs)

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----------------------------------------------------------------------

Date: 29 Nov 92 01:55:00 GMT
From: [e-mail]
Subject: Chicago DC-10 (Was Re: Shuttle replacement)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes...
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
> They
>don't have to worry about things like asymmetric slat deployment (which
>killed all aboard the Chicago DC-10).

You sure about that on Henry? I thought it was the loss of an engine and a
engine emergency routine (they did not know it fell off) that stated you had
to throttle back the other engines when this happened. The asymmetric slat
deployment (due to the loss of hydraulics on the wing where the engine fell
off) was only a contributing factor.

Dennis, University of Alabama in Huntsville

------------------------------

Date: 29 Nov 92 02:50:13 GMT
From: Henry Spencer <[e-mail]>
Subject: Chicago DC-10 (Was Re: Shuttle replacement)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>> They
>>don't have to worry about things like asymmetric slat deployment (which
>>killed all aboard the Chicago DC-10).
>
>You sure about that on Henry? I thought it was the loss of an engine and a
>engine emergency routine (they did not know it fell off) that stated you had
>to throttle back the other engines when this happened. The asymmetric slat
>deployment (due to the loss of hydraulics on the wing where the engine fell
>off) was only a contributing factor.

My understanding is that it was the asymmetric slat deployment that killed
them.  Having the engine fall off isn't that much worse than just having
it lose all thrust; there have been other engine-falls-off incidents with
much less drastic outcomes.  Engine out just after takeoff -- heavy, low,
and slow -- was a first-class emergency all right, but a very standard
sort of problem that pilots see regularly in the simulator.  That alone
wouldn't have caused the crash.  The lethal damage was not the lost
engine, but the mess it made of the wing's leading edge as it departed,
which breached plumbing for all the wing's hydraulics and immobilized
its slats.  Throttling back wasn't that bad in itself; it caused the
crash only because it made symmetric slat deployment vital, and that
didn't happen.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

------------------------------

Date: 29 Nov 92 00:33:12 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: escape systems
Newsgroups: sci.space

>He is correct -- every manned Apollo had the escape tower.
>
>In fact, the Shuttle is the ONLY American manned spacecraft to have
>flown without an escape system.
>
>Unfortunately, it is the only one that ever needed to use one.

   Well just a nitpick here, but Gemini and Space Shuttle both used
   Ejection Seats and survival in either system was consider very low.
   In fact, when Gemini 6 misfired at T+1 second in 1965, Wally Schirra
   opted to stay on top of the Titan rather than use the ejection seats.
   This despite the fact that Titan was fully fueled, a few inches off
   the launch cradle, and the engines had conked-out. That's not exactly
   a testament to the Gemini escape system.

   -Brian

------------------------------

Date: 29 Nov 92 01:29:00 GMT
From: "Charles R. Martin" <[e-mail]>
Subject: Evil wicked flying bombs!
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (James Davis Nicoll) writes:

   In article <[e-mail]> [e-mail] (Charles R. Martin) writes:
   >
   >Just a quibble, but it's real damned hard to get a n-weapon to go off in
   >a crash.  This  is a direct correlary of the fact that it's hard to get
   >one to go off at all.


       N-weapons, at least in NATO, are also carefully designed to not
   go off unless the  proper procedures are followed. If  you don't know the
   PAL codes, improper arming should leave the user with a mildly  radioactive
   paperweight. Modern nukes have spiffy electronic 'locks' which are said to
   be next to impossible to crack. I think most of the older devices with
   mechanical security devices have been retired.

Ja, shoor.  But there are good physical reasons beyond these that make a
bomb unlikely to be detonated by simple impact or fire and impact, at
least without some specific design features that I think we can assume
are uncommon (read "I don't want to fly with it if I can set it off with
a kitchen match!")

But detonating a fission device depends on getting the subcritical
masses close together sufficiently fast, with no silly little moderators
or impurities nearby, and keep them together (by inertia) until the
fission chain reaction is energetic enough to make a nice big bang.  (To
some extent, the longer they're together, the bigger the bang for the
buck.  However, everything I know about bomb design is limited to the
Los Alamos First Course from WWII.)  This requires sufficiently limited
conditions that its well-nigh impossible to do by accident.
--
        Charles R. Martin/(Charlie)/[e-mail]
     Dept. of Computer Science/CB #3175 UNC-CH/Chapel Hill, NC 27599-3175
        3611 University Dr #13M/Durham, NC 27707/[phone]
     "Oh God, please help me be civil in tongue, pure in thought, and able
      to resist the temptation to laugh uncontrollably.  Amen." -- Rob T

------------------------------

Date: 29 Nov 92 02:06:39 GMT
From: Henry Spencer <[e-mail]>
Subject: launch windows
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>   Let's not throw stones at expendables when Martin just launched Mars
>   Observer within it's original window, while the Shuttle missed all of
>   it's deep space windows.

Uh, sorry, this wasn't the original window for Mars Observer.  The original
MO window was two years ago.

Not quite a fair comparison, given that the MO delay wasn't caused by the
launch vehicle.  But bear in mind that Galileo and Ulysses would probably
have missed their spring-1986 window even if they had been on Titans,
since Titan was down for several months then too.  *All* US heavy launchers
were grounded during the 1986 Jupiter window.  I don't think it's fair to
blame the shuttle for missing that one.

In the end, not one of those three missions (Galileo, Ulysses, Magellan)
fell prey to the sort of problem that the Pasadena Party Line ascribes
to the shuttle:  one crew-safety-related delay after another slipping
launch past the end of the window.  After one catastrophic delay due to
a major launch failure, all three went up within their windows.  I don't
think any of them was even as late in the window as Mars Observer was.

What you *can* legitimately blame on the shuttle (more precisely, on the
way it's run) is the *length* of that one catastrophic delay.  The Jupiter
windows are roughly annual, and Titan-launched missions could have gone
up in the 1987 window; a year would have been ample for investigation and
recovery, even given how protective NASA was about Galileo (it wasn't
an accident that Ulysses was flying first, to try out the Shuttle/Centaur
system before Galileo used it).  The longer delays were mostly the politics
of (US) manned spaceflight.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

------------------------------

Date: 29 Nov 92 02:06:00 GMT
From: [e-mail]
Subject: Military History (Was Re: Shuttle replacement)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Allen W. Sherzer) writes...
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>Those gliders only flew during
>very good weather. As it is, they only saw very limited use because they
>where judged too dangerous.
>

The Gliders flown in the Normandy Invasion saw limited use because the utility
of gliders in warfare is very limited. The high casualty rate of the glider
force was mainly due to their being deployed in the dark and the landing
field consisting of cow pastures.

This was the only time gliders were used in mass in WWII or at any other
time in warfare. Before WWII it was not feasable and after WWII the Helicopter
had replaced it.

Dennis, University of Alabama in Huntsville

------------------------------

Date: 28 Nov 1992 22:52:43 GMT
From: Jeffrey Alan Foust <[e-mail]>
Subject: Not at Caltech? (was Re: NASA Daily News for 11/24/92 (Forwarded))
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>
>The location for the Dec. 3 Town Meeting has been changed to
>Cal State Dominquez Hills.  I've already informed Charles
>Redmond who puts out the NASA Daily News.

The town meeting is being held in the University Theater on the CSU-Dominguez
Hills campus (1000 E. Victoria Street, Carson: east of the 110 freeway, between
the 91 and 405 freways), according to the info I got in the mail a couple
weeks back from NASA.

I imagine the main reason (or at least a contributing reason) behind the change
is that the meeting would have conflicted with the infamous ME 72 Design
Contest, which is being held at the same time as the town meeting would have
been held at Caltech.  The town meeting would have been consigned to a smaller
auditorium, and if the NASA town meeting planners are expecting a large (>400)
number of people showing up, they may have decided to make the change.

--
Jeff Foust                        Senior, Geophysics/Planetary Science, Caltech
[e-mail]                       [e-mail]
        Tom Seaver: "Hey, Yogi, what time is it?"
        Yogi Berra: "You mean now?"

------------------------------

Date: Sun, 29 Nov 1992 01:40:30 GMT
From: Henry Spencer <[e-mail]>
Subject: shuttle destruct
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>   By the way, does anyone know if the Shuttle has destruct charges on the
>   orbiter itself? I know the SRBs and ET do, what about the orbiter?

It doesn't.  NASA does not like destruct charges aboard the spacecraft
themselves, and defended not having them aboard the orbiter by pointing
out that the orbiter has very little ability to go anywhere under power
without the ET.  (The purpose of destruct charges is not to shred the
vehicle, but merely to make the impact point(s) predictable by ensuring
that all rocket thrust stops.)  It's very likely, mind you, that
destroying the ET would tumble the orbiter badly enough to destroy it,
a la Challenger.

>   If a Shuttle lost power and ground-zero was Orlando, could NASA blow up
>   the Shuttle out over the Gulf?

Before main-engine cutoff and ET separation, you betcha.  (Although it
wouldn't be NASA doing it -- the USAF handles this function for the whole
Cape operation.)  Afterward, e.g. during landing, as with any aircraft,
avoiding crashes is the pilots' responsibility.

>What about DCX in same situtation?

I assume you mean DC-1 (DC-X is an suborbital demonstrator that will never
get anywhere near Orlando!).  The intent is that it will handle safety
the way aircraft do:  it's the pilots' job.  I'm not sure quite what they
plan to do about this when the thing flies unmanned -- it's intended to
be flyable either way -- because although existing unmanned aircraft
typically don't carry destruct charges, there aren't many of them and
the issue hasn't really come up seriously yet.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

------------------------------

Date: 29 Nov 92 00:31:27 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

>>       No, you can LAUNCH 3 satellites for the cost launching one from
>>the shuttle.  You can't build them though.
>
>Sorry. I can build and launch a typical satellite for ~$200 million. $600M
>is a low cost for a Shuttle launch. (Others may claim the cost closer to
>$500M but those people are only considering operational costs and ignoring
>NASA overhead, orbiter depreciation, development amortization, and other
>costs which easilly add over $100M per flight).
>
>   Allen

      I think what Gary was getting at, Allen, is that you would have to
      build those three satellites in the first place to ensure success.
      Either you spend that money up front (greatly reducing your savings)
      or build another satellite after the first launch fails. Building and
      buying satellites presently takes many years, costing you more money
      in lost revenue.

      I'm not sure where this discussion started, for it seems to imply
      Space Shuttle perfection. I certainly don't. :-) Two satellites were
      lost on Shuttle Mission 10 (STS-41B). TDRS-B and SPARTAN-A were lost
      aboard Challenger. However expensive, though, Shuttle *did* have a
      very good record delivering satellites.

      Consider that several Space Shuttle missions launched three commercial
      satellites, all of the hardware for this was already in the inventory,
      and in the meantime all of the expendables (even Ariane) suffered
      launch failures. If, say, 15 of the missions since Challenger had each
      launched three comsats, the U.S. could have picked up some money. Not
      nearly enough to cover costs, but at least this money would not have
      been handed over to ArianeSpace. With the backlog, it seems likely
      NASA would have tweaked the system to carry four comsats per mission.
      (by tweaking, I mean manifesting and maneuvering, not safety or payload
      weight... that's no problem even with four HS-376s).

      In the meantime, the money that the U.S. spent on the old Delta, Atlas,
      and Titan lines could have been invested in NLS, NASP, DCX, or whatever.
      Hindsight may be 20/20 here, but it seems to me that we had a way to
      alleviate the backlog *and* invest in a Shuttle replacement back in
      1986-88, but we missed the opportunity.


      -Brian

------------------------------

Date: 29 Nov 92 00:32:01 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

>>and your customer go to your competitors. Having
>>on site startup personnel is a major plus that's worth a considerable
>>sum of money for expensive space systems.
>
>The companies who went with Shuttle went out of buisness long ago. They
>paid too much for launch costs.
>
>   Allen

    Wait a second, Allen... I though Shuttle prices were very competitive
    with Ariane. If not, why on Earth did those customers sign on to
    Shuttle? In fact, NASA was subsidizing launches to make prices
    competitive. France does the very same thing with Ariane. Nobody went
    out of business because they launched on the Space Shuttle.

    -Brian

------------------------------

Date: 29 Nov 92 00:13:47 GMT
From: Henry Spencer <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>Perhaps you could answer a question: if this 'high performance rocket fuel'
>>is so dangerous why is it that about a million pounds of the stuff
>>couldn't blow up a Shuttle orbiter only inches away from it?
>
>Actually it seemed to do a pretty good job of making that flight
>unsurvivable...

Please go read the Rogers Commission report, Gary, or stop pontificating
on the subject altogether.  Your ignorance is showing.  The million-odd
pounds of fuel in the external tank had nothing to do with the accident.
If it hadn't ignited, the outcome would have been identical.  The orbiter
broke up because it was thrown violently out of control at Mach 3, and
what threw it out of control was structural failures in the external tank
and the SRB struts, caused in various ways by the SRB joint failure.
The fuel burn (it was not an explosion), although it *looked* impressive,
contributed absolutely nothing; the orbiter was already breaking up when
it began.

Quotes and page numbers on request.

>... A major fire in flight is
>unsurvivable anyway. That's the glider's advantage, it can't burn
>in flight.

So why weren't *all* your helicopter landings done by autorotation?
The big fire hazard isn't in flight, it's after a too-hard landing.
If gliders are so much better, surely every landing should be made
that way.

In fact, gliders make up for their fire resistance by having a
zero-defects landing procedure that is unsuited to operational service.
Which is why no airline would even consider an airliner built to make
gliding landings routinely.  For operational service, it's strictly an
extreme-emergency fallback for fortunate cases of unlikely accidents.

Please shut up about gliders, Gary, they aren't relevant.

>... Wind gusts are the worst.

For vehicles relying on aerodynamic lift (wings or rotors), that is.

>... That all takes fuel margin.

Certainly, which is why VTOLs need (and have) fuel margins.  As we've
been telling you.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

------------------------------

Date: 29 Nov 92 00:23:34 GMT
From: Henry Spencer <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>I'm sure Allen or Henry will say it momentarily... the DCX is very
>unlikely to lose all power on the way in. True enough, but this discussion
>appears to be of worst-case scenarios (at least when directed at the
>Shuttle) so I chose the worst case scenario for a DCX accident, too.

Worst-case scenario for any flying device is loss of all control or loss
of all lift (or sufficiently asymmetric loss of lift to make control
impossible).  It is 100% fatal for 747 or DC-1.  DC-1's lift producers,
which are also its main control system for low-speed work, are more
complex and less reliable than those of a 747, so it makes up for this
by having more of them and being able to tolerate failures better.
Certification to similar standards of reliability is envisioned; the
certification authorities -- experts on the subject -- appear to feel
that it is plausible.

>KSC landings do indeed come VERY close to flying overhead. I'm not worried,
>because if the thing were off course, the Shuttle pilot could point his
>(or her, soon) ship into the Indian River or the marshes out west.

Note that if he loses his APUs, he can't point the ship anywhere, because
neither he nor his computers have any control without hydraulic power.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

------------------------------

Date: 29 Nov 92 01:25:20 GMT
From: Steinn Sigurdsson <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:

   In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:

   >   We spent half a billion $$ to recover $75 million worth of satellites. Only
   >   a NASA employee could consider that a good deal.

   >Come on Allen, you can't charge the whole cost of the flight to
   >the rescue, this has been hashed out a dozen times -

   On the mission in question Shuttle did little if anything else.

   But I would be interested in seeing your cost model which justifies
   satellite rescue. Proponents of Shuttle haven't been able to offer

Ok, I claim one technology demonstrator is justified (a proof of
concept mission showing recovery of a several ton package not
necessarily desgined for recovery), and I claim that each
shake out flight for a new orbiter can justifiably be used to
to further demos, as you don't want critical missions on first
flight but can fly missions of opportunity.

   one. BTW, just picking an application you like and charging it the
   marginal costs doesn't cut it since the other users won't like it.

   Also remember that recovered satellites aren't worth as much as new ones.
   I believe the two satellites in question where sold for about half price.

   >   ERROR: You are assuming LDEF as is was the one and only way to get this
   >   infromation. This is incorrect.

   >True, but just exactly who was doing it a different way?

   The Russians.

So where's the data?

   >As LDEF is it
   >as of now should not all the benefit derived from it be credited to
   >the shuttle program?

   Along with all the blame. Including the tens of millions wasted and the
   experiments ruined because of the unreliability and expense of Shuttle.

Fair enough, I never claimed the shuttle was perfect, just give
it the credit due and stop focusing on the roads not taken

   >Irrespective of whether it would have been
   >better&cheaper some mythical other way?

   Look, just because it doesn't exist today doesn't make it mythical. If you
   want to show that it CAN'T be done, then do so. Engineers project the
   capabilities of machines not yet built all the time. I do it myself for
   the proposals I write and projects I work on.

Oh, I'm not nearly senior enough a scientist to start claiming
that some projects CAN'T be done ;-)

Look, I agree with you that things could have been done
better, I'd love to see the DC program succeed, but I don't
think you're doing anyone any favours (at least on this forum)
by exaggerating the capabilities of the DC or by underestimating
the shuttle...

|  Steinn Sigurdsson    |I saw two shooting stars last night        |
|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

------------------------------

Date: 29 Nov 92 02:53:13 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:

>>Of course you've lost you launch window for your probe for the next
>>umpty ump years while you build the next one and stack another launcher...

>   Tread very carefully here, Gary. I'm as big a supporter of the Space
>   Shuttle as anyone, but I do remember a Space Shuttle 'malfunction'
>   a few years back which screwed the heck out of three deep space
>   mission launch windows...


This is another interesting point. A brief examination of Shuttle schedules
will show that Shuttle has actually cancled most of its flights.

That's reliability.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------147 DAYS TO FIRST FLIGHT OF DCX----------------------+

------------------------------

Date: 29 Nov 92 03:04:01 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:

>>Sorry. I can build and launch a typical satellite for ~$200 million.

>      I think what Gary was getting at, Allen, is that you would have to
>      build those three satellites in the first place to ensure success.

Since one satellite on an expendable has a 90%+ chance of success, I think
building one will do. Now if it is critical then I can build two (at less
than twice the single unit cost) and buy two launchers. That boosts my
reliability to 99% or so and saves me over $200 million in the process.

If it was YOUR money, which would you pick?

>      aboard Challenger. However expensive, though, Shuttle *did* have a
>      very good record delivering satellites.

That's not what you said about Galelio in a previous posting. Look at early
Shuttle manifests and you will see that the record wasn't all that good.

>      If, say, 15 of the missions since Challenger had each
>      launched three comsats, the U.S. could have picked up some money.

Look, the bottom line is that if you spend more than you take in you haven't
picked up any money. Had we acted intelligently, we could have put those
payloads on US commercial launchers and MADE money.

    Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------147 DAYS TO FIRST FLIGHT OF DCX----------------------+

------------------------------

Date: Sun, 29 Nov 1992 03:12:24 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:

>>The companies who went with Shuttle went out of buisness long ago. They
>>paid too much for launch costs.

>    Wait a second, Allen... I though Shuttle prices were very competitive
>    with Ariane.

We where referring to a hypothetical situation where Shuttle users paid the
actual costs. Gary seems to feel Shuttle is worth three times the cost.

I for one object to having my tax dollars paid to subsidize commercial
enterprises and snuff out cheaper commercial launchers.

I can't see it as anything but a big step backwards for us all and I
don't see why you don't agree.

>Nobody went out of business because they launched on the Space Shuttle.

That is because they had suckers like us to pay their bills for them.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------147 DAYS TO FIRST FLIGHT OF DCX----------------------+

------------------------------

Date: 29 Nov 92 00:32:40 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: What comes after DC-1
Newsgroups: sci.space

>>I have no problem with a devil's advocate. However, I hope future articles
>>will have more technical content than 'it hasn't happened yet, so it never
>>will'. What specific objections do you have? Do you feel engine performance
>>isn't achieveable? Are the margins too small? Do you think the tanks will
>>be too heavy? Everybody who has looked at this in detail says a SSTO vheicle
>>can be built. 1.5 stage vehicles have been making orbit for 30 years.
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Will someone please tell me the name of this marvelous machine?
Atlas? Well just barely. The Mercury flights made orbit on 1.5 stages, but
they couldn't do much once they got there. Ever since, the 1.5-stage Atlas
has been flown with a second stage (Agena or Centaur).

The Space Shuttle is a 1.5-stage system, but I can hardly imagine Allen or
Henry using it to justify DCX!

-Brian

------------------------------

Date: 29 Nov 92 02:22:43 GMT
From: Henry Spencer <[e-mail]>
Subject: What comes after DC-1
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>>>... 1.5 stage vehicles have been making orbit for 30 years.
>                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>Will someone please tell me the name of this marvelous machine?
>Atlas? Well just barely. The Mercury flights made orbit on 1.5 stages, but
>they couldn't do much once they got there.

What do you want them to have done?  Landed on the Moon?  They met all
their (unambitious but not trivial) mission objectives.

Atlas, with no Centaur, can put about 3000lbs in low orbit.  Maybe a bit
more today, since Atlas has been improved a bit since Mercury days.  That
is not a huge payload, but it's not useless by any means.  You could run
a very nice space program with just that, if you worked at it.  If you ask
the laser-launcher people, they'll tell you that the *largest* item which
absolutely must be launched in one piece is a human plus life support.
That is, a Mercury capsule.

>Ever since, the 1.5-stage Atlas
>has been flown with a second stage (Agena or Centaur).

Correct, because the customers wanted bigger loads and higher orbits.  So?

>The Space Shuttle is a 1.5-stage system...

No, the shuttle has two stages, which burn in parallel.  The feature that
makes Atlas 1.5-stage is not parallel burn, but dropping engines rather
than an entire stage.  While nobody else has copied this approach, that's
partly because there hasn't been much from-scratch liquid-fuel launcher
design in the US since then.  One of the more recent incarnations of NLS
was a 1.5-stage design, with six STMEs (four booster, two sustainer)
underneath a shuttle external tank with a Titan payload shroud on top.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

------------------------------

Date: 29 Nov 92 03:07:32 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: What comes after DC-1
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:

>>>can be built. 1.5 stage vehicles have been making orbit for 30 years.
>                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

>Atlas? Well just barely.

Barely is close enough. Technology has gone a long way in the 30 years
since Mercury.

The point is that we have been very close for a long time. Everybody who has
taken a serious look at SSTO has concluded it can be done with today's
technology.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------147 DAYS TO FIRST FLIGHT OF DCX----------------------+

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End of Space Digest Volume 15 : Issue 470
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