Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V16_0/V16NO024.ZIP/V16NO024

Internet Message Format | 1993-07-13 | 24KB

Date: Sat,  9 Jan 93 05:00:12
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #024
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat,  9 Jan 93       Volume 16 : Issue 024

Today's Topics:
                       *** BUSSARD RAMSCOOP ***
                            averting doom
                    DC-1 and the $23M NASA Toilet
                        Delta Clipper (2 msgs)
                         killing the shuttle
                         Logo on Delta rocket
          Making Antimatter (was: *** BUSSARD RAMSCOOP ***)
    Proposal for sci.geo.eosdis has not been adequately discussed?
      Question:How Long Until Privately Funded Space Colonizati
                         Question about SETI
           question on privately funded space colonization
                      RTG's on the Lunar Module
    Should NASA operate shuttles (was Re: Shuttle a research tool)
              Subjective Safety Measure(Re: man-rating)

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

Date: 8 Jan 93 14:48:19 GMT
From: Dave Jones <[e-mail]>
Subject: *** BUSSARD RAMSCOOP ***
Newsgroups: sci.space

[e-mail] wrote:
> Henry Spencer's ramscope talk sparked a question in my small mind.  How can
> we talk about the performance of antimatter propulsion without knowing
> the mass fuel ratio? How much hardware does it take to contain a "tank" of
> antimatter (magnetic fields, etc.)?  Does anyone have the input required
> for insertion into the rocket equation???
>
You're just using the antimatter to heat hydrogen, so the rocket's
efficiency is of the same order as the Nerva nuclear design: Isp = 850-1500
or so, depending on how well it can be engineered.

Robert Forward claims that the storage requirements of anti-H2 are modest
if you use low enough temperatures and store it in solid form.  Annihilation
only occurs at the surface of the solid and can be controlled.

I think we already had this discussion......

--
||------------------------------------------------------------------------
||Dave Jones ([e-mail])|Eastman Kodak Co. Rochester, NY  |

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

Date: 8 Jan 93 12:55:00 GMT
From: William VanHorne <[e-mail]>
Subject: averting doom
Newsgroups: sci.astro,sci.space,sci.physics

In article <[e-mail]> [e-mail] (Blair P. Houghton) writes:
>Do you seriously believe that a species capable of creating
>and enjoying The Love Boat is capable also of learning
>galactic engineering?
>
Son, if there's a buck to made doing it, It Will Be Done.
Amen.

---Bill VanHorne

-------------------------------------------------------------------------------
"And when the world is overcharged with inhabitants, the last remedy is Warre;
 which provideth for every man, by Victory or Death" - Thomas Hobbes "Leviathan"
-------------------------------------------------------------------------------

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

Date: Fri, 8 Jan 1993 14:32:57 GMT
From: Thomas Clarke <[e-mail]>
Subject: DC-1 and the $23M NASA Toilet
Newsgroups: sci.space

Funny, no one has mentioned that the toilet budget and the
DC-X budget are about the same! :-(
--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
[phone], FAX: [phone], [e-mail]

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

Date: Fri,  8 Jan 1993 09:31:07 -0500
From: David Allen Markley <[e-mail]>
Subject: Delta Clipper
Newsgroups: sci.space

I know this may have already flown by on the net, but I'll ask it anyway:

Does anyone have the design goals for the Delta Clipper program?
Specifically I'd like to know what performance they hope to acheive and
by when.

Thanks for any info,

++David

[e-mail]
N3N?? (T+55 days since the exam)
++David

Computing Services
[e-mail]
[phone]

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

Date: 8 Jan 93 15:30:47 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Delta Clipper
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (David Allen Markley) writes:

>Does anyone have the design goals for the Delta Clipper program?
>Specifically I'd like to know what performance they hope to acheive and
>by when.

the DC-Y goals are 20,000 pounds to LEO (10K to polar) with an operational
cost of $1 to %10 million per flight and one week turnaround of the
vehicle (three days in an emergency). In addition, there is a crossrange
requirement for a single orbit mission and some delta-V on orbit.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------106 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Fri, 8 Jan 1993 13:47:34 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: killing the shuttle
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

>You don't get rid of civil servants and politically-powerful contractors
>that easily.  If you wipe out the Imperial Deathstar, they'll only start
>building another one.

Today that's true. However, if the conditions existed where a group was
powerful enough to end Shuttle then the situation would be so different
that it is impossible to say what would happen.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------106 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 8 Jan 93 16:03:43 GMT
From: Gary Hughes - VMS Development <[e-mail]>
Subject: Logo on Delta rocket
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Bob Mills 609-490-3211) writes...
>[e-mail] (Tim Harincar) writes
>>
>>What about the big RCA logo on the Delta rockets (as seen in "the
>>Illustrated Encyclopedia of Space Technology")? I hope RCA had to pay
>>for that.
>>
>I'm not 100% sure, but I think it worked something like this:
>1.  Customer (RCA Americom) contracts with satellite vendor


[rest deleted]

In addition to the reasons already mentioned, in the case of the Delta 3920,
RCA funded a significant part of the development costs of the launch vehicle as
well. They needed something to launch their second generation Satcoms (aka
Advance Satcom family) and the shuttle schedule was too late. The 3920 design
goal was to carry an Advanced Satcom and it's associated PAM-D.

For those launches, they were entitled to a giant logo :-)

In general, the Delta often had the logo of the client organization along with
the triangular Delta logo (sometimes the Delta logo had a mission logo merged
into it) as far back as Aerial-1 (UK satellite). Some of the SDIO missions
(Delta Star, Delta Stake) have had interesting logos.

gary

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

Date: Fri, 8 Jan 93 13:59:59 EET
From: [e-mail] (F.Baube x554)
Subject: Making Antimatter (was: *** BUSSARD RAMSCOOP ***)

Henry Spencer <[e-mail]> writes:
> A production setup the size of the Hanford works ..
> Kilogram quantities are probably going to have to be made in space,
> not so much for handling reasons (although those aren't trivial)
> as because of the sheer amounts of *energy* needed.

I hope this means DEEP space, as opposed to Earth orbit.
If this operation were run like Hanford or Rocky Flats
or any other such shining example of US atomic management,
I'd rather be on Mars thank you when there's a leak.

--
* Fred Baube         ..when you think your Toys  you hear Laughter
* Optiplan O.Y.           * have gone Berserk    cracking through the Walls
* [e-mail]       * it's an illUsion     you're sent Spinning
* GU/MSFS/88              * you Cannot Shirk     you Have No Choice
* #include <disclaimer.h> *                 -- ancient Sioux saying

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

Date: 8 Jan 93 14:47:25 GMT
From: J R Evans <[e-mail]>
Subject: Proposal for sci.geo.eosdis has not been adequately discussed?
Newsgroups: news.groups,sci.geo.geology,sci.space,sci.astro,sci.geo.fluids,sci.geo.meteorology

A Call For Votes for sci.geo.eosdis has been issued by [e-mail].
The proposal represents a significant development within the sci.geo
sub-heirarchy, in that it appears to sponsor a moderated group which will
be used for the dissemination of material from a single source to a small
community.  I feel this proposal needs discussion, as the CFV fails to
show why this objective cannot very satisfactorily be fulfilled through a
mailing list. (I say this as one with a potential interest in the material).
As far as I can determine, no Request For Discussion on this topic has been
received at this site (the highest upstream of several to which I have
access), and I can say with certainty that no related messages have
appeared in sci.geo.geology or sci.geo.fluids, which I read assiduously.

It is not clear to me precisely how this situation has arisen, but
I suggest that interested users of these groups should be offered an
opportunity to comment before proceeding.  On the other hand, I do not
see how that can fully be accommodated within the guidelines.

Russ Evans
British Geological Survey, Edinburgh

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

Date: 6 Jan 93 17:20:46 GMT
From: Dani Eder <[e-mail]>
Subject: Question:How Long Until Privately Funded Space Colonizati
Newsgroups: sci.space

[e-mail] (Chris Marriott) writes:

>In article <[e-mail]> [e-mail] writes:

>>
>>What are the current estimates of folks in this newsgroup of how long it
>>will be until the world starts to see privately funded space colonization?
>>
>>I've noticed that there are some _extremely_ capital intensive schemes around
>>which might make the marginal cost of launching mass to orbit fairly cheap.
>>(I'm thinking of mechanisms like Clarke's space "elevator" or Bull's
>>gun). I'm more interested in technologies like the Henson Sling or SSTO
>>technology that might be more useful to private citizens and less likely to
>>be shelved or monopolized by governments or mega-corps.
>>
>>
>>Thanks!
>>

>The "space elevator" - basically dropping a cable from a geosynchronous
>satellite to Earth (and, of course, another one upwards so the centre of
>mass stays still) is probably the most *lethal* device one might conceive
>of building!  Imagine the cable breaks near the mid-point.  You have 38000km
>of cable falling to earth at *orbital* velocities, enough to wrap itself
>around the entire equator of the planet!  Go figure out the kinetic energy
>involved.  How much ocean would it vaporize?  Massive medium-term climatic
>changes at best - "nuclear winter" scenarios.  A new Ice Age a distinct
>possibility.

I have to comment on the above in sequence:

1) Given my income stream, I could save $15,000 per year.  At six
percent compounded, I would have $80 million in today's dollars
in a century.  By then, it should be within that cost due to improvements
in technology.  So a century would be an upper bound.  One billionaire
could fund a private space colony out of his assets if he wanted to
and spent the money intelligently.  So the lower bound is zero time.

2) Gerald Bulls gun, or the much-improved versions of gas guns that
are being developed, would be expensive by ordinary human scale,
but cheap in relation to current space costs. The gas gun design I
am working on at Boeing is estimated to cost less than 2 Ariane IV
launches to build (<$130 million), or less than one 747-400 aircraft
to buy.

3) The Space Elevator that reaches to GEO is the limit case of
the large class of possible orbital structures.  Given today's
material strengths, it is not economic to build a full space elevator.
It is, however, resonable to build a structure several thousand
km long, whose bottom end is substantially slower than orbit
velocity (by 2-3 km/s), and using an elevator the rest of the
way.

4) Let us assume a cable with a lifting capacity of 1 million
pounds of payload has a tensile strength of 2 million psi.
This is twice the strength of today's materials, but you wouldn't
build such a thing until you have suitable materials.  If you
use a working strength of 2/3 (factor of safety = 1.5), then
the scale length of the cable is 500 km.  The cross section
must increase by a factor of e per scale length going up the
gravity well.  The earth's gravity well is equivalent to 6375
km deep, and from the surface to GEO is equivalent to 6,230 km
deep.  Thus you have 12.5 scale lengths, thus the cable is
exp(12.5)=268,000 times the cross sectional area at GEO as
at the bottom end.  Given a working strength of 1.33 million psi,
the tip cross section is 0.75 square inch.  So the GEO
cross section is 200,000 square inches, or 37 feet.

With a cross section of 130 sqaure meters, a length of 35000
km, and a density of 1900 kg/m^3, we have a total mass opf
8.64x10^12 kg, or 8.65 million tons.  Allowing for the fact
that the thing is not the full width the whole length, and
not all of it is falling from GEO, let us reduce this to
4.3 megatons of falling stuff.

Something falling from GEO hits the surface at close to
escape velocity, so has about 14 times the energy content of
TNT (4.2MJ/kg) to dissipate, so the equivalent energy
is 60 Megatons of TNT.  This is definitely a lot, but it
can be compared to the yield from one Trident- Class
nuclear submarine, which comes in at 87 Megatons.

5) For economy's sake, a full GEO system would not be built
as a hanging cable all the way from GEO.  Using the same
strong materials, you would build a tower up from the
ground to meet it, with the same number of scale lengths
in each structure, for minimum mass.  Compressive
towers are not as strength-efficient as cables.  They can
achieve about 40% the effective strength.  Therefore,
the span will be covered by a tower and a cable, each 9
scale lengths long each.  The maximum cross section of
the cable is then 8000 times the bottom tip, or 4 square
meters.  The impact energy is then reduced to less than
2 Megatons, still a serious matter but hardly a climate-
changing one.

6) For safety's sake and to make it manufacturable and
deliverable, the cable will probably be made in strands
about 1 cm across (ever try to wind a cable 2 meters
thick on a drum?) and no more than 10 km long.  This
produces cable reels massing about 2 tons each, which
is a manageable construction item.  The parallel strands,
all 40,000 of them, will be spread apart in space to
protect against accidental impact by spacecraft or
space debris.  With 1 km inter-strand spacing, the
structure is 200 km wide at the GEO point, tapering
down to a set of 4 strands in a square pattern 1 km
apart at the cable-tower join point ( which will
be at a height of 1200 km).  The tower then expands
outward from there to a width of perhaps 60 km at
the base.

7) The total mass in space is on the order of 200
kilotons of cable, at a price of about $40/kg hypothesized
for large scale production of high strength carbon fiber, for
a material cost of $8 billion.  So we are talking a couple
of tens of billions total project cost.

With a elevator capable of 30 kph, it will take
1000 hours to raise a cargo to GEO, so today's elevator
technology is not suitable for people, but okay for
bulk items.  A mono-rail type device running at
300 kph up to GEO would take 4 days to ride.  This
is more reasonable.  At 1000 tons x 90 deliveries per
year x 12 year amortization, we are talking about
an amortized cost of $20/kg to GEO.  This compares
to the present cost of $20,000/kg to GEO, a hell of
an improvement.

Dani Eder

--
Dani Eder/Meridian Investment Company/[phone](w)/232-7467(h)/
Rt.1, Box 188-2, Athens AL 35611/Location: 34deg 37' N 86deg 43' W +100m alt.

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

Date: Fri, 08 Jan 93 15:57:22 MET
From: [e-mail]
Subject: Question about SETI

In answer to Francois Yergeau (8 Jan 93 04:10:48 GMT):

>>                                                           A laser
>>crams all its energy into just one specific wavelength. If you are
>>receiving the signal, you split the light into a spectrum. Now stretch
>>out the spectrum. The whitish light from the star is diluted more and
>>more as it is stretched, while the single narrow spectral line from the
>>laser keeps its intensity. With enough stretching of the spectrum, the
>>laser will eventually stand out clearly. (N. Henbest)

>Wrong.  No laser has an infinitely narrow linewidth.  Even if you could
>build one, you would induce a finite linewidth by modulating it to
>carry your message.  Thus spectral dispersion stops being beneficial at
>some point, and if you haven't recovered your signal by then, you're
>dead. (F. Yergeau)

Rather obvious. I think (at least, I hope) that Nigel Henbest was making
some kind of journalistic approximation. Most New Scientist's readers
are not professional scientists, just amateurs.

>> Laser beams are
>>also narrow: whereas a radio signal spreads out as it travels through
>>space, diluting its power all the way, you can use comparatively
>>little power with a laser because it does not spread out. (N. Henbest)

>Completely bogus.  All electromagnetic beams diffract.  In fact, you
>can make a radio beam just as well collimated as a given laser beam;
>you just need a much larger antenna. (F. Yergeau)

IMHO, Nigel Henbest knows that too, since he wrote previously in
his article: "Television is increasingly being transmitted [by cable
or] by satellites that beam only onto a small region of the Earth,
with no wastage into space." But maybe he contradicts himself in
the article (as journalists do too often).

>Francois Yergeau ([e-mail]) |  De gustibus et coloribus
>Centre d'Optique, Photonique et Laser    |  non disputandum
>Departement de Physique                  |     -proverbe scolastique
>Universite Laval, Ste-Foy, QC, Canada    |

It seems that you have about the same credentials as Stuart Kingsley:

<     Stuart A. Kingsley is a fiber optic consultant and Director of the
< world's first Amateur Optical SETI Observatory.  He received a B.Sc.
< Honors and Ph.D. in Electronic and Electrical Engineering from The
< City University, London (1972) and University College London (1984),
< respectively (England).  He worked at Battelle Columbus Division as
< Principal Research Scientist and then as Senior Research Scientist from
< 1981 to 1987.  He has been involved in producing a variety of fiber-
< optic sensors, including fiber-optic rotation sensors.  He invented
< the fiber-optic line-stretcher and fiber-optic line-squeezer phase
< modulators that are now important components in fiber-optic sensor
< systems.  He shared a 1984 Rank Prize in Optoelectronics for pioneering
< work on fiber-optic sensing.

It seems also that you disagree with him (see EJASA, January 1993).

J. Pharabod

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

Date: 8 Jan 93 13:40:19 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: question on privately funded space colonization
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:

>If it's the principle of eminent domain that you're worried about, then
>yes, that could theoretically happen. But the same applies to activities
>on the Earth.

No, it's worse than that. For example, up untill a few weeks ago government
policy made it impossible to have a private remote sensing. Under the old
policy, the DoC could grant a licence for a satellite but then later
could revoke it for any reason. Nobody is going to invest in remote
sensing under these conditions.

BTW, the first private remove sensing licence was issued on Jan 4 to
Wroldview. This was made possible by the commercial space additions
to the NASA authorization. The commercial additions themselves where
made possible by the space activists who worked to get it and the
Omnibus Commercial Space Act passed.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------106 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 8 Jan 93 16:50:57 GMT
From: "Peter J. Scott" <[e-mail]>
Subject: RTG's on the Lunar Module
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> The radiation hazard from plutonium 238 is insignificant; it's pretty much
> a pure alpha emitter, and human skin stops alpha particles completely.  (A
> sheet of paper will do likewise.)  You don't want to eat the stuff, but so
> long as it stays put, no sweat.

Somewhere in the recesses of my mind lies a memory of a scientist
who offered to eat some plutonium if the journalist covering the
event would eat the same amount of caffeine.  No takers, obviously,
but does this mean that it would be safe to eat plutonium?  If it's
inert it should be passed in due course with only the mucus coating
the alimentary canal getting irradiated.

--
This is news.  This is your       |    Peter Scott, NASA/JPL/Caltech
brain on news.  Any questions?    |    ([e-mail])

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

Date: 8 Jan 93 13:45:08 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Should NASA operate shuttles (was Re: Shuttle a research tool)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Francois Yergeau) writes:

>>So what is so special about human space flight?

>The market, for one thing.  Spin off shuttle to the private sector, and
>you're likely to get at most one provider, and one buyer (NASA).

Nonsense. Run KSC like an airport and Shuttle like an airliner. There is
no reason that several companies couldn't buy Shuttles and lease the
hanger facilities like any other airport.

The market is small because NASA keeps it small.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------106 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Fri, 8 Jan 1993 14:59:18 GMT
From: Robert Turner <[e-mail]>
Subject: Subjective Safety Measure(Re: man-rating)
Newsgroups: sci.space,sci.aeronautics

In article <[e-mail]> [e-mail] (Ken Arromdee) writes:
>In article <[e-mail]> [e-mail] (Thomas Clarke) writes:
>>The rating of transportation system safety by fatalities per
>>passenger mile always struck me as bogus.  Subjectively, what
>>matters is the probability of exit.  That is if I climb in and
>>close the door, what are my chances of opening the door and
>>climbing out.  By this measure the STS is only about 1 in 50,

Isn't the elevator considered the safest mode of transportation meeting both the
"if I get in, I get out" and "deaths per passenger mile".

Robert
--
Robert Turner [phone] Semiconductor Systems Design Technology, Motorola
[e-mail]   OR   ...!uunet!dover!turner
GOD is real, unless declared integer. --J. Allan Toogood

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

End of Space Digest Volume 16 : Issue 024
------------------------------