Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_4/V11_480.TXT

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Subject: SPACE Digest V11 #480

SPACE Digest                                     Volume 11 : Issue 480

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Today's Topics:
                Re: Radiation
             Re: Space Sail Race
     Re: Ulysses plutonium essay in *The Nation*, 14 May
        mars vs. venus, which is easier to terraform?
            "Super Guppy" being phased out
              Re: Imperial units
             Re: Current Ramjets?
                Re: Radiation
                Re: Radiation
             Re: Space Sail Race
          Re: "Super Guppy" being phased out
             Re: Space Sail Race
----------------------------------------------------------------------

Date: 2 Jun 90 15:59:38 GMT
From: sumax!ole![e-mail]  (Mike Upton)
Subject: Re: Radiation


Re: RAD Hard pricing

Of course there are many different types of RAD-Hard.
Devices can be designed for total-dose, single event upset (SEU), neutron flux,
etc.
Some devices are designed to perform after, but not during, rad exposure.
For space based applications you want the device to operate during
radiation exposure, so both total dose and SEU requirements must be
satisfied.
Cost for RAD hard chip for space purposes, range from 10 to 100 times
the cost of similar non-RAD chips.

At one point Haris had a price of $1200 for an S class (space application)
RAD hard 8085 8 bit microprocessor,
thats just for the micro chip, not the whole system.

Radiation causes crystal defects and threshold shifts in the silicon,
in CMOS once the thresholds have shifted too far the devices will stop working.
RAMs are effected by the charge induced in the silicon by heavy particals,
such as alphas, causing the internal state in the RAM to become corrupted.

Mike Upton
--
Michael Upton@Seattle Silicon
{....!uw-beaver!sumax!ole!upton, sumax!ole!upton@uw-beaver}
/*           Semi-conducting our business since 1983        */

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

Date: 2 Jun 90 08:16:33 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Space Sail Race

In article <[e-mail]> [e-mail] (Thomas G Edwards) writes:
>... The article claims that
>various space sails from six countries will be launched for the
>event.  They also claim that NASA has agreed to provide the
>team with free launch and technical advice.

As of earlier this week, as far as the head of the Canadian Space Society
team knew, no decision had been reached on who would be providing the
launch(es), and it didn't look like it was going to be free.

I'd be very surprised to see NASA providing a free launch for JHU; they
send few payloads to high orbit, and I'd be surprised to see enough
spare payload capacity on one of them to let even one sail piggyback.
And a NASA-provided launch *has* to be a piggyback on a NASA payload,
because NASA no longer operates any launchers except the shuttle, which
is nearly useless for solar sails because it doesn't go high enough.

(Solar sails have major problems with air drag, and need to start in
geosynch-transfer orbit *at least*.  A high orbit would be much better,
because a sail starting from GTO spends a year or so dipping into the
Van Allen belts often, and needs heavily radiation-hardened electronics.)

The launch situation and funding situation also are likely to have a
considerable effect on the number of participants, and there is a fair
chance that some would-be participants will drop out before the finale.
The drop-out rate has already been high; of 30-odd North American teams
that formally indicated intent to participate, *four* actually submitted
proposals (CSS, JHU, MIT, and the World Space Foundation).  So far, the
only entry that really looks solid is the Italian team, which has both
the Italian government and the Italian aerospace industry behind it and
already has a piggyback launch promised (on an Italian comsat).
--
As a user I'll take speed over|     Henry Spencer at U of Toronto Zoology
features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry [e-mail]

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

Date: 2 Jun 90 16:30:19 GMT
From: crabcake![e-mail]  (Kenneth Arromdee)
Subject: Re: Ulysses plutonium essay in *The Nation*, 14 May

In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
>Last year NASA launched the Galileo probe with 49 pounds of plutonium aboard to
>power its "radioisotope thermal generators" (NOT reactors).  These device
>provide electrical power to the spacecraft.   Next October they plan to launch
>the Ulysses solar probe, with similar RTG's carrying 24 pounds of plutonium,
>which Grossman and Long describe as "the most toxic substance known." Ulysses
>is a project of the European Space Agency.

Oh-oh, they're at it again....

Does anyone have any good references to exactly _how_ toxic plutonium is?
Hopefully when the next round starts on this newsgroup we'll be ready so there
won't be thousands of postings of the same factoid over and over again....
(This also includes how toxic the particular _form_ of plutonium is used, since
the technophobes don't seem to know the difference between isotopes.  Also
facts such as that if burning plutonium produces finely-divided oxide particles
which are easy to breathe that's irrelevant if the plutonium on the spacecraft
is already in oxide form....)
--
"And they shall be cast out where there is no outlet for their evil doings..."
    -- the Book of Ubizmo, on sinful uses of electricity

Kenneth Arromdee (UUCP: ....!jhunix!arromdee; BITNET: arromdee@jhuvm;
     INTERNET: [e-mail])

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

Date: 2 Jun 90 23:16:20 GMT
From: zaphod.mps.ohio-state.edu!uwm.edu!ogicse!unicorn![e-mail]  (Michael Kinsella)
Subject: mars vs. venus, which is easier to terraform?

Which do you expect to be easier to terraform, mars or venus?

why?

how long do you think it would take if the level of government interest
was equal to government interest in 'atomics' during the cold war?

how would you proceed?

Judging from the discussion onterraforming venus, we (that is, the
3 member committee behind the typist) think mars would be easier.

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

Date: 2 Jun 90 19:23:01 GMT
From: mailrus!news-server.csri.toronto.edu!helios.physics.utoronto.ca!physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Subject: "Super Guppy" being phased out


   Well, I never quite got around to posting this question when it was
timely, but here goes.
   We heard on the net a while back that the "super guppy" used to
transport large cargoes was being/was going to be phased out this year.
   At the last Toronto SEDS conference there was a presentation about
the shipping container of the ANIK-E comsat to be launched in December
of this year from an island spaceport (maybe on top of an Ariane, but I
have a vague recollection that it's an american rocket that will be
used). Anyway, the container was designed around the dimensions of the
super guppy's cargo space, down to centimetre tolerances. The fit is so
tight that when they put the overpressure in the container to keep dust
out, it didn't quite fit into the test space.
   Now, is the super guppy still going to be flying the satellite to the
rocket, or is a new scheme going to have to be devised? My understanding
was that no other cargo airplanes would be able to carry the container.


--
 Christopher Neufeld....Just a graduate student  | He's the kind of person
 [e-mail]              | who'd follow you into a
 [e-mail]          Ad astra! | revolving door and come
 "Don't edit reality for the sake of simplicity" | out first.

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

Date: Sun, 3 Jun 90 00:19:55 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Imperial units


>From: van-bc!rsoft!mindlink![e-mail]  (Bruce Dunn)
>Subject: Re: archaic units

>> [e-mail] writes:
>> >I'm not sure about new programs in general, but the official units for
>> >the space station are imperial units, because of fears that astronauts
>> >might forget how long a centimeter is in a crisis.

As I pointed out last year, if safety and quick response are the main
consideration, it's better to come up with an application-specific set of
units, rather than try to stick with "standard" or SI.

>     The official units may be imperial (or should that be American)

At last! Someone who realizes there's a difference, and from a Commonwealth
country. :-) The American Standard and British Imperial units for length
and mass are very slightly different. The units of volume are substantially
different.

I have a friend who has served on many international standards committees.
He claims that Americans are actually pretty good at standards, they're just
not as obsessed with them as are Europeans, for instance. From my viewpoint,
there are two major problems with our current mix of standards:
 - While one can get a metric ruler or meter stick, it seems to be impossible
   to buy a long metric tape measure.
 - Our thermodynamics textbooks are a nightmare of three or four different
   sets of units. A large part of the effort is wasted on unit conversion.
   (Does anyone know of a good all-SI thermo textbook written in English?)

BTW, the dreaded cgs system is still alive and well in many current reference
books. I can see how it might take a reference like the CRC Handbook quite a
while to update all its entries. It's still annoying.
                    John Roberts
                    [e-mail]

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

Date: 2 Jun 90 00:58:00 GMT
From: usc!cs.utexas.edu!ntvaxb![e-mail]
Subject: Re: Current Ramjets?

In article <[e-mail]>, [e-mail] (Vincent Cate) writes:
> I have found a few examples of ramjets that were really built and flown:
>
> Bomarc:  Surface to air missile.
>          Powered by a RJ43 ramjet.
>
> Talos:   Surface-to-air missile.
>
> Navajo - Mach 3 cruise missile.
>          Designed to fly at 75,000 feet for up to 5000 miles.
>          Used two Curtiss-Wright 48-inch diameter ramjets.
>          Successfully test-flown.
>
> Lockheed X-7:  Powered to more than Mach 4 at over 80,000 feet
>          by a Marquardt ramjet (possibly the Marquardt XRJ59-MA-3).
>
> Vega:    Powered to Mach 4.06 at 96,500 feet.  Nord Aviation of France.
>          Seems to have gotten up to Mach 5 and up to 115,000 feet but
>          maybe not both at the same time.
>
>
> However, all of these are pre 1963.  Are there any currently flying
> ramjet-powered missiles or planes?  It seems like ramjets would be
> ideal for air-to-air missiles.  Can anyone give me any pointers
> to sources with information about more modern ramjets?  Are there
> any off-the-shelf ramjets for sale?
>
> The reason I am interested is that it looks like ramjets are the best way
> to get from a B-52 to around 4,000 MPH.  At this point rockets, or maybe
> scramjets when they are developed, could be used to get to orbit.  Seems
> like it might not be too hard to get from the Pegasus to a ramjet first
> stage Pegasus II (wings and starting speed are already there).  If there is
> an off-the-shelf ramjet that would work it might even be an easy evolution.
>
> Thanks for any info,
>
>     -- Vince

One of the current-model Soviet SAMs (SAM-10 or SAM-11, I can't remember)
is supposed to be a ramjet...



C Irby

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

Date: 2 Jun 90 03:53:02 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Radiation

In article <[e-mail]> [e-mail] (alan herbst) writes:
>H. Peter [e-mail] questioned:
>>How much protection would these rad-hard memories provide...
>
>and
>Henry [e-mail] stated:
>>It *does* seem to be hard to find solid quantitative data on them...
>
>Referring to the June, 1987 catalog for Harris Semiconductor entitled
>"RAD-HARD/HI-REL CICD DATA BOOK", the following data is offered...

While I appreciate the effort, Alan, you've taken the quote from me out
of context:  my complaint was about lack of quantitative information
about the Van Allen belts, not about lack of same for semiconductors.
Unfortunately, nobody seems to publish a Van Allen Belt Databook...
--
As a user I'll take speed over|     Henry Spencer at U of Toronto Zoology
features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry [e-mail]

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

Date: 2 Jun 90 13:56:34 GMT
From: njin!uupsi!uhasun![e-mail]  (Jon Bloom)
Subject: Re: Radiation

In article <[e-mail]>, [e-mail] (John Nordlie) writes:
>
> I would also like some info on the U of Surrey sats now in orbit.
> I was building a receiveing setup for UOSat 1, when the damned
> thing burned up.  What is needed to receive the new sats?
>
Wel, UoSAT 2 uses exactly the same downlink (modem) system as UoSAT 1,
except the data is inverted.  (Why?  I don't know!)  Of the two new
UoSATs, one appears to be dead.  The other one is currently operating
a 9600 bit/s downlink, I believe.  The demodulator for that is, I
believe, available from AMSAT-UK.  (I'm not at work right now so I
don't have their address handy.  If you need it, email me.)

Jon

--
Jon Bloom, KE3Z                              | American Radio Relay League
Internet: [e-mail]         |
Snail:    225 Main St., Newington, CT 06111  | "I have no opinions."

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

Date: 2 Jun 90 14:08:53 GMT
From: cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!maytag!watdragon!watyew![e-mail]  (Brian or James)
Subject: Re: Space Sail Race


    A few possibly foolish questions: How long will the race
take, what size payloads are we talking [minute, I expect], and
will there be any kind of sensors on the solar sail craft? I
would not be suprised if there is very little or no radio gear on
board; solar sails shouldn't be all that hard to spot with a
telescope. I wonder how wide these sails or going to be.
What happens to the sailcraft when the race is over?
                        JDN

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

Date: 2 Jun 90 23:53:48 GMT
From: attcan!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: "Super Guppy" being phased out

In article <[e-mail]> [e-mail] (Christopher Neufeld) writes:
>   We heard on the net a while back that the "super guppy" used to
>transport large cargoes was being/was going to be phased out this year...
>   Now, is the super guppy still going to be flying the satellite to the
>rocket, or is a new scheme going to have to be devised? ...

There are several operational Super Guppies still in existence, owned by
Airbus Industrie and used to fly pieces of Airbus airliners from plants in
England and Germany to the final-assembly site in France.  I imagine one
of them could be chartered for a suitable price.

Even those are nearing the end of their lifetime, though.  Airbus has no
plans to switch to surface transport, however, and is now looking at
"guppying" some old A300s as replacements.
--
As a user I'll take speed over|     Henry Spencer at U of Toronto Zoology
features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry [e-mail]

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

Date: 2 Jun 90 23:03:01 GMT
From: attcan!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Space Sail Race

In article <[e-mail]> [e-mail] (Brian or James) writes:
>    A few possibly foolish questions: How long will the race
>take, what size payloads are we talking [minute, I expect], and
>will there be any kind of sensors on the solar sail craft? ...

Years; solar sails are not fast.  As I recall, the only required
payload is a 1kg plaque, although at least some of the competitors
are interested in carrying a bit of science payload.  Not sure quite
what you mean by "sensors", but there's a reasonable chance most of
them will carry a small camera.

>would not be suprised if there is very little or no radio gear on
>board; solar sails shouldn't be all that hard to spot with a
>telescope. I wonder how wide these sails or going to be.

Think 100m or so across.  But they do need communications:  these are
complex guided spacecraft, not pretty parachutes thrown out at random.
(If nothing else, they *have* to be guided to work their way up out of
Earth orbit -- that is a tedious process with a lot of maneuvering.)

>What happens to the sailcraft when the race is over?

Much the same as what happens to the usual run of spacecraft:  they end
up wherever they end up.  The mission is a race to the vicinity of Mars,
and most of the sails won't be too overdesigned for that, so there will
be limits to what else can be done with them.
--
As a user I'll take speed over|     Henry Spencer at U of Toronto Zoology
features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry [e-mail]

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

End of SPACE Digest V11 #480
*******************