Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_238.TXT

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From ota Mon May 30 03:06:55 1988
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Date: Mon, 30 May 88 03:06:34 PDT
From: Ted Anderson <ota>
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Subject: SPACE Digest V8 #238

SPACE Digest                                      Volume 8 : Issue 238

Today's Topics:
              Soviet nuclear satellites
                 Mir elements
             Space Services et al
              Vocabulary lesson #7:  ALS
       A high volume Earth to high orbit launch system
     Re: A high volume Earth to high orbit launch system
     Re: A high volume Earth to high orbit launch system
     Re: A high volume Earth to high orbit launch system
     Re: A high volume Earth to high orbit launch system
     Re: A high volume Earth to high orbit launch system
----------------------------------------------------------------------

Date: 25 May 88 18:51:10 GMT
From: cfa!cfa250![e-mail]  (Jonathan McDowell)
Subject: Soviet nuclear satellites

As already mentioned briefly in this newsgroup, Soviet Fleet
Intelligence's nuclear reactor satellite Kosmos-1900 lost stationkeeping
ability around Apr 12, according to orbital data from NASA.  As of May
22 it was in a 246x260 km orbit and continuing its slow decay.
Furthermore, the nuclear fuel core has not been ejected (After K-954
fell on Canada, they redesigned the satellites to eject the most
radioactive part so that it would not reach the ground intact due to the
shielding of the rest of the satellite).  However, its companion RORSAT
Kosmos-1932 successfully boosted its reactor to a 923x1011 km orbit at
about 0700 GMT on May 20 and ejected its nuclear fuel core shortly
thereafter.  So we don't have to worry about that one for a few
centuries.  Meanwhile a couple of their naval electronic intelligence
sats have just been deorbited, and a very busy series of launches has
occurred from Baykonur, including the successful launch of three GLONASS
navigation satellites on a Proton on May 21.  The previous attempted
GLONASS launch ended in failure in February.


Av Week suggests an August launch for their Shuttle, which I find
plausible.


Jonathan McDowell

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

Date: 24 May 88 04:07:00 GMT
From: [e-mail]
Subject: Mir elements


Mir
1 16609U          88139.81771683 0.00015382           99963-4 0  2050
2 16609  51.6180 218.2070 0021873 343.2888  16.7524 15.75351119129209
Satellite: Mir
Catalog id 16609
Element set 205
Epoch: 88139.81771683
Inclination:  51.6180 degrees
RA of node: 218.2070 degrees
Eccentricity:  0.0021873
Argument of perigee: 343.2888 degrees
Mean anomaly:  16.7524 degrees
Mean motion: 15.75351119 revs/day
Mean motion acceleration: 0.00015382 * 2 revs/day/day
Epoch Revolution: 12920

Semimajor axis:    6721.73 km
Apogee height*:     358.27 km
Perigee height*:     328.86 km


        Source: NASA Goddard via T.S.Kelso's `Celestial RCP/M'

* Apogee and perigee altitudes are referred to the mean radius of the
  Earth (6378.15 km), and not to the local radius of the geoid.  They
  are only approximate, and should not be used for orbit prediction.

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

Date: 7 May 88 15:42:52 GMT
From: pasteur!agate!garnet.berkeley.edu![e-mail]
Subject: Space Services et al

Space Serices Incorporated of America, the Houston based firm marketing
the Conestoga rocket, announced Thursday that the DARPA had chosen them
to compete in a phase I study contract for launch services.  The studies
are to be completed by July 25, after which one or two of the
competitors will receive hardware contract offers.  The other firms
doing phase one studies are LTV, TRW and Lockheed.

William Baxter

ARPA: [e-mail]
UUCP: {cbosgd,sun,dual,decwrl,decvax,ihnp4,hplabs,...}!ucbvax!math!web

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

Reply-To: pnet01![e-mail]
Date: Sun, 8 May 88 14:46:36 PDT
From: [e-mail] (Jim Bowery)
To: crash![e-mail]
Subject: Vocabulary lesson #7:  ALS

ALS, noun abrv., a program optimally designed to create uncertainty and
business risk among those who might develop commercial launch vehicles
by keeping open the possibility of the government developing and
subsidizing one as was done with Space Shuttle.

UUCP: {cbosgd, hplabs!hp-sdd, sdcsvax, nosc}!crash!pnet01!jim
ARPA: crash!pnet01![e-mail]
INET: [e-mail]

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

Date: 8 May 88 14:42:38 GMT
From: mcvax!unido!ecrcvax![e-mail]  (John Gregor)
Subject: A high volume Earth to high orbit launch system

How many people out there are familiar with the "Launch Loop" concept by
Keith Lofstrom?  Have any of the sci.space regulars (Eugene, Henry, Dani
(are you still out there?), etc.) taken a look at the concept?  I'd
really like to hear some opinions on it.  Here is a reference to the
paper:

AIAA-85-1368
The Launch Loop: A Low Cost Earth-To-High-Orbit Launch System
K. H. Lofstrom, Launch Loop,
Portland, OR
AIAA/SAE/ASME/ASEE 21st Joint Propulsion Conference
July 8-10, 1985
Monterey, California

I'll do my best to give a very brief summary:

The launch loop employs a very long and very thin iron ribbon moving at
high velocity.  The speed is, in fact, great enough that an upwards
force is generated by the ribbon.  This force is used to support a
control track to maintain stability and two large (5000 metric ton)
deflection stations.

The basic idea is that the West station dangles cables down to the
surface (Yes, 80km is easily within the strength of todays materials).
Payload is raised via these cables out of the way of most of the
atmosphere.  The payload is then set over the moving ribbon.  It hovers
over and is accelerated by eddie current repulsion between the ribbon
and the cargo container.  It accelerates at 3g for the 2000km length of
the ribbon at which point it has achieved orbital velocity.

Highly schematic diagram (Warp to conform to Earth's curvature):

+----------------------- 2000km -----------------------------+
|                                                            |
             #________________________________________#              -+
    ___---|                                         ---___         | 80km
(---======================================================---)    -+

= -> Surface of the Earth
- -> Ribbon, control track, etc. (The stair steps should be gently sloping
                  lines.  I hate ascii graphics)
( -> West deflector magnet.
) -> East deflector magnet.
# -> East and West station.
| -> Cable from West station.

The paper goes into quite a bit of detail and answers most questions
people have come up with (so far).  I would REALLY, REALLY, REALLY
recommend getting your hands on a copy, before commenting on the idea.
I'll even go so far as to mail (even though I am currently in Germany)
people copies if they can't find copies any other way.

I really think it is an incredibly ingenious solution to the problem of
getting things into space.  It has the posibility to launch 400 metric
tons of cargo into high orbit PER HOUR!!!!  If you don't believe me,
don't flame, READ THE PAPER!  I'd really like to get into some
discussions with those more knowledgeable in engineering than I am.

Again, please get a copy of the paper and read it.  I want to know why
we aren't doing reasearch on this device.

John Gregor  -  [e-mail]

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

Date: 11 May 88 06:41:49 GMT
From: ssc-vax![e-mail]  (Dani Eder)
Subject: Re: A high volume Earth to high orbit launch system

In article <[e-mail]>, [e-mail] (John Gregor) writes:
> How many people out there are familiar with the "Launch Loop" concept
> by Keith Lofstrom?  Have any of the sci.space regulars (Eugene, Henry,
> Dani (are you still out there?), etc.) taken a look at the concept?
> I'd really like to hear some opinions on it.  Here is a reference to
> the paper:

Not only have I read the paper, but I know Keith.  In fact, he was on
usenet at one time (you out there?).  The advanced propulsion community
is really a very small one.

> I really think it is an incredibly ingenious solution to the problem
> of getting things into space.  It has the posibility to launch 400
> metric tons of cargo into high orbit PER HOUR!!!!  If you don't

400 tons of cargo is a piddly-ass amount.  One airport runway with a
stream of 727s taking off represents 1200 tons of passengers and cargo.

> Again, please get a copy of the paper and read it.  I want to know why
> we aren't doing reasearch on this device.

Define 'we'.

My personal opinion of the launch loop is that is is an overly complex
solution to the problem with failure modes that could be used for
special effects in a George Lucas film.

The ribbon of metal in the launch loop is really a series of strips
about one meter by ten centimeters by a millimeter each.  They are
constrained to follow the back and forth path by a string of control
magnets that sense the position of the ribbon.  The turnarounds at each
end are done by big magnets.

What I worry about is what happens if one of the turning magnets fails
(keeping in mind that everything manmade fails eventually) then the
ribbon continues straight into the ground behind the turning magnet,
creating a pile of slag in a crater, as for several minutes a continuous
stream of one pound slugs hits the ground at 11,000 rounds per second.
On the return leg of the loop, a part of the ribbon is missing.  The
resulting unbalanaced forces may leave metal strips flying every which
way in earth orbit.

To my way of looking at design, I would like my support structure to be
passive rather than active.  The loop in the launch loop is what holds
up the structure by moving at super-orbital speeds.  The same result can
be obtained with a tower made of modern structural materials (such as
graphite epoxy for compressive columns and fiberglass/ kevlar/
polyethelyne for guy wires.)

You can support an accelerator (linear motor, mass driver, whatever)
from a series of towers of increasing height with suspension bridges
strung between the towers.  If the power goes down, your structure does
not fall out of the sky.

Using towers also allows for incremental construction.

Dani Eder / Boeing / Space Station Program / uw-beaver!ssc-vax!eder
[phone](w) [phone](h) 1075 Dockside Drive #905 Huntsville,
AL 35824  34 40 N latitude 86 40 W longitude +280 ft altitude, Earth

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

Date: 10 May 88 21:00:41 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: A high volume Earth to high orbit launch system

> How many people out there are familiar with the "Launch Loop" concept
> by Keith Lofstrom?  Have any of the sci.space regulars (Eugene, Henry,
> Dani (are you still out there?), etc.) taken a look at the concept?
> ...

I met Keith once upon a time and got a copy of what was probably an
early draft of the paper.  I could not see anything disastrously wrong
with the idea, although I'm not an expert in the technologies involved.
To my mind it has a couple of modest practical flaws shared by most of
the (so to speak) mechanical Earth-to-orbit schemes:

1. It works much better on a large scale than on a small one, so it's
    impractical to start with a little one and use its revenues to
    bootstrap up.  All the money has to be raised up front.

2. It's big enough and fragile enough to be very vulnerable to attack
    by clever terrorists.

These are not insuperable obstacles, but they do present problems.  He
may have addressed them since.

NASA is to spaceflight as            |  Henry Spencer @ U of Toronto Zoology
the Post Office is to mail.          | {ihnp4,decvax,uunet!mnetor}!utzoo!henry

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

Date: 13 May 88 17:27:15 GMT
From: tektronix!sequent!mntgfx![e-mail]  (Mike Butts)
Subject: Re: A high volume Earth to high orbit launch system

>From article <[e-mail]>, by [e-mail] (Dani Eder):
> In article <[e-mail]>, [e-mail] (John Gregor) writes:
>> How many people out there are familiar with the "Launch Loop" concept
>> by Keith Lofstrom?.........
>
> To my way of looking at design, I would like my support
> structure to be passive rather than active.  The loop in the
> . . .
>
> Using towers also allows for incremental construction.

Incremental construction is an important, and often neglected, point.  A
look back at the history of technology shows the successful technologies
are those which can be developed incrementally.  Small scale, lower risk
*useful* initial implementations are almost always needed to pave the
way for full scale projects.  They offer engineering experience,
profits, and a track record, all of which are *required* to lower the
risk enough to raise funding for something big and new.  This has been
true for centuries.  (Take a look at James Burke's Connections and The
Day the Universe Changed for abundant popularized examples.)

Technologies which must be built on a large scale to work at all are
what you might call "You can't get there from here" technologies.  The
"N plus one" ideas are the ones that get funded.  Sad, but very true.

A major weakness of Keith's elegant Launch Loop idea (in my opinion) is
that you need a full scale system before you can get the first kilogram
into orbit.  Keith has been developing ideas for smaller-scale testbeds
to develop the technology, but they don't actually launch anything.

Of course the potential benefits of such technologies can be so great as
to justify taking a big risk (again in my opinion), but finding any real
entity with real cash willing to take that big a leap has nearly always
proven to be impossible.

Mike Butts, Research Engineer         KC7IT           503-626-1302
Mentor Graphics Corp., 8500 SW Creekside Place, Beaverton OR 97005

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

Date: 14 May 88 08:15:24 GMT
From: [e-mail]  (Kian-Tat Lim)
Subject: Re: A high volume Earth to high orbit launch system

Incremental construction projects are easier to get funded than
all-at-once type projects, but it seems to me that they also are much
more readily stalled in mid-development before achieving the final goal.
By selling bureaucrats on "just let us have this little bit" you
simultaneously allow them to say back to you "you got your bit last
year, why are you back now?".

For examples, look at the attempted construction of the Santa Monica
Mountains National Recreation Area: land was supposed to be bought
incrementally, in what was called a great advance in federally-financed
park construction.  What happened?  Appropriations were minimal after an
initial surge, and developers quickly moved in to snap up and
irrevocably damage prime property.

A science-fiction version of this can be found in Robert Forward's
Flight of the Dragonfly, in which an incrementally-constructed Fresnel
lens has its funding put off for so long that it cannot be completed in
time to slow down the interstellar spacecraft in the story.  I'm not
advocating the use of SF to bolster real-world arguments, but I believe
that this type of action by Congresscritters and such has much
precedent.

Kian-Tat Lim ([e-mail], GEnie: K.LIM1)

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

Date: 13 May 88 11:44:18 GMT
From: mcvax!ukc!its63b![e-mail]  (ERCF08 Bob Gray)
Subject: Re: A high volume Earth to high orbit launch system

In article <[e-mail]> [e-mail] (Dani Eder) writes:
>What I worry about is what happens if one of the turning magnets fails
>(keeping in mind that everything manmade fails eventually) then the
>ribbon continues straight into the ground behind the turning magnet,
>creating a pile of slag in a crater , as for several minutes a
>continuous stream of one pound slugs hits the ground at 11,000 rounds
>per second.  On the return leg of the loop, a part of the ribbon is
>missing.  The resulting unbalanaced forces may leave metal strips
>flying every which way in earth orbit.

One proposed solution to this is to put the entire launch loop into
orbit. (Don't laugh)

Cables can then be dropped from the orbiting ring to the ground. The top
of the cable is attached to a cradle floating on a magnetic field. The
ring turns but the cradle can "hover" above any point above the Earth's
equator.

The worst case accident is if the orbital ring breaks.  The remains of
the ring then fall UP, away from the Earth.

The design is described in a series of articles in the "Journal of the
British Interplanetary Society" called "Orbital rings and Jacob's
ladders" which appeared in 1983or 1984 (I think).

The author clains that the ring is buildable using today's technology.
The original design called for liquid helium cooled superconducting
magnets. If high temperature superconductors would work, the cost of
building would drop even more.

Eventual cost was something of the order of $36 billion.  Using lunar
materials and a bootstrap technique, this would drop to about $17
billion.  (I don't have the article here, so those are only remembered
figures, but are of the right magnitude).

Cost to orbit would be $0.04 per pound.

The articles then go on to describe how to use orbital rings to provide
a very fast and cheap Earth-Moon transit system.

The author then starts to get a little more far-fetched and describes
how to terraform Jupiter using them, but I will save that for another
posting. :->
    Bob.

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

End of SPACE Digest V8 #238
*******************