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Subject: SPACE Digest V11 #120

SPACE Digest                                     Volume 11 : Issue 120

Today's Topics:
               Re: Rocket Info
           space news from Jan 29 AW&ST etc
              Galileo Update - 03/05/90
    Space capsules (was Re: space news from Jan 22 AW&ST)
               Re: Rocket Info
----------------------------------------------------------------------

Date: 6 Mar 90 17:32:03 GMT
From: zaphod.mps.ohio-state.edu!uwm.edu![e-mail]  (Russ Brown)
Subject: Re: Rocket Info

>
>I'm preparing a simple programming assignment for my students and I wonder
>if someone could give me some figures.  Does anyone have a rough estimate of
>mass of a rocket (esp. Saturn V)?  How about fuel capacity?  How about
>a conversion factor between kilograms of fuel and thrust (in Newtons)?
>--
Heres some stuff from "Bound for the Stars", Adelman & Adelmand, Prentice-
Hall, 1981. (Chapter 5)

- One pound of hydrogen and oxygen burning for one second exerts 456
pounds of force. This gives it a 'specific impulse' of 456 seconds.
"Hydrogen-Oxygen is the highest specific impulse of any chemical
combination of fuels in use today".

- Takeoff mass of the Apollo 11 spaceship was 2,902,216 kg. First
stage thrust was 34.1 million Newtons.

Comparison of modern engines:

             J-2              SSME
----------------------------------------------------------
MASS OF ENGINE     1530 kg           2835 kg
THRUST (VACUUM)  1.02 x 10^6 N     2.08 x 10^6 N
THRUST-WEIGH RAT    68:1              81:1
SPECIFIC IMPULSE    430 sec          455 sec

You might try to find this book at the library. Also, Encyclopedia
Britannica has a table of specific impulses in the macropedia
article on "energy conversion", or something like that. And the
section on space exploration has data on each of the launch vehicles.

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

Date: 6 Mar 90 04:30:10 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: space news from Jan 29 AW&ST etc

Editorial applauding the retrieval of LDEF, but observing that NASA had
to choose between LDEF and Solar Max, and lamenting that the $20M LDEF
cost far more than that to launch and retrieve and is unlikely to fly
again.

IBM subcontracts operating system for space station to Lynx Real-Time
Systems Inc, a 30-employee company  in California!

NASA seeks $200M in FY91 for lunar/Mars technology work in seven areas:
regenerative life support, aerobraking, orbital propulsion, lunar-base
nuclear power, uses of lunar/Martian soil, radiation protection, and
nuclear propulsion.

Truly recommends to Space Council that "the first decade of the 21st
century" be the target goal for a lunar base.  [Call it 19 years.
Apollo took 8.  I'm not impressed.]

NASP prime contractors submit a tentative agreement to join together in
a consortium to pillage the taxpayers, er excuse me I mean build NASP,
more efficiently.  The FY90-91 DoD budget authorization act will designate
NASP as a pure research vehicle, to do an end-run around antitrust laws.
Rockwell is designated team leader, possibly partly because it has stuck
most firmly to the original idea of maximizing use of air-breathing
propulsion and minimize dependence on rockets.

SDI's LACE satellite being prepared for launch on a Delta.  The main
payload is the Low-power Atmospheric Compensation Experiment, in which
sensors scattered over booms and panels extending from the bird will
measure distortion of a low-power laser beam aimed at the satellite
from the surface.  Auxiliary payloads include a pair of ultraviolet
cameras to study UV tracking of rocket plumes, and an Army/Los Alamos
experiment to measure neutron background in space.  There may also be
"a fourth, classified experiment... believed to be developmental
hardware for detecting nuclear blasts", which is not from SDI.

LDEF is on the ground again.  The backup plan, for use if Syncom could
not be deployed -- take LDEF on board, boost up to a higher orbit, and
deploy it again pending a still later retrieval (!) -- was not needed.
Landing was delayed a day by fog at Edwards, and delayed one more orbit
by a failure in Columbia's #5 computer (#4 replaced it for the landing).
The astronauts took their time coming out after landing, and are generally
taking it easy, after the longest US spaceflight in fifteen years [a whole
11 days, sigh...].  LDEF will go back to KSC aboard the orbiter, partly
because this will contaminate it less than separate shipping and partly
because removing a payload that big would require moving quite a bit of
equipment from KSC to Edwards temporarily.  The 747 will make three
stops rather than the usual one, because the unusually heavy load limits
fuel load.

Hubble launch slips a month as incomplete test data raises doubts about
seals on Discovery's SRBs.  They will be taken apart and re-stacked.

Secret DoD launch of Atlantis slips six days, probably a payload problem.
The bird is "AFP-731", with both digital imaging systems and eavesdropping
receivers, and it will go into an unusually high-inclination orbit,
62 degrees.

Only two more military payloads are on the shuttle manifest after this
one, and the USAF asst. sec. for space says no more are planned, although
the option will remain open.  "We don't have anything that specifically
requires the manned capability..."  [Translation, everything requiring
the manned capability was shelved because the USAF's expendables have
no manned capability.]

First Ariane launch of 1990 goes perfectly, carrying Spot 2, plus six
amateur radio satellites on a new auxiliary-payload carrier platform.
This launch, Jan 21, ends a hiatus in Ariane operations due mostly to
payload problems.  [Of course, there is now going to be another hiatus,
since the *next* Ariane launch wasn't so smooth...]  On reaching orbit,
Spot 2 was deployed, the Ariane third stage turned 180 degrees and
deployed UoSAT D and E, and then turned back 25 degrees to release
Microsats A-D.  The individual UoSAT/Microsats were deployed by springs
of different strengths to ensure separation.  The UoSAT/Microsat folks
split the secondary-payload bill of about $170k (normally $600k, but
this was the first flight of the new secondary-payload platform).

Several pages of photos of LDEF in space.

MBB is defining a subscale model of Sanger's hypersonic first stage,
for use in validating design and propulsion.

Letter from J.R. French [a well-known name in astronautics] criticizing
AW&ST's "Laurels" award to the team that put together NASA's initial
response to Bush's Moon/Mars initiative.  "...simply a rehash of the
sort of thing NASA has been promoting all along, namely taking 15
years to do what we once did in eight, starting with nothing... NASA
spent the 90-day study justifying a pre-established position rather
than doing any new thinking... `space station Freedom', recently
downscaled because of budget problems, magically grows back to the
old configuration for Moon-Mars.  This is design to preconception --
not design to need..."

[Something that wasn't in AW&ST at all, that I saw, but reached me by
more obscure channels:  NASA has placed an order with Rockwell for a
set of shuttle structural spares, to replace the ones being used to
build Endeavour.  Apart from being useful in themselves, they preserve
the option of ordering another orbiter in the next year or two.]

[From Spaceflight, Jan issue:]

Salyut 7 is out of fuel and tumbling, and the Soviets are studying how
to deorbit it safely.  Reentry will occur in 3-4 years as things stand.
One possibility is to dock a Progress or Soyuz and use its engines to
deorbit Salyut.  Reports that Buran would be used to bring Salyut down
for examination are described as "a kind of fantasy", presenting various
problems with solar panels and structural support, that does not seem
worthwhile at present.  Salyut has been unmanned in a high parking orbit
since 1986, although there were reports that astronauts would return to
it eventually.

ESA and UK agree to establish an Ariane telemetry station on Ascension
Island.

The mothballed shuttle pad at Vandenberg will be converted for Titan 4
launches.  The USAF would have preferred to build a new Titan pad, but
Congress balked at the price tag.

[From Flight International, 31 Jan:]

NASA places firm contract for launch of Mars Observer on Commercial
Titan in Sept 1992.

McDonnell Douglas starts development of the Aeroassist Flight Experiment
on NASA contract.  It will fly the first operational test of aerobraking.
In May 1994 it will go up on Endeavour, fire a solid-fuel motor to drop
its orbit into the atmosphere, fly an aerobraking pass, and then boost
itself back up into orbit for recovery by Endeavour.

Soviets plan a second-generation materials-processing satellite [the US
having yet to build a first...], the Nika-T series, to fly first in 1993
aboard the Zenit booster.  It will be heavier than the current Photon
series, and will include solar panels to permit a 120-day mission (as
compared to Photon's 16 days).  The return capsule will have nearly
triple the current 450kg capacity, although it will continue to be
based on the Vostok capsule (which first flew as Sputnik 4 in 1960).

[From the 26 Jan issue of Science:]

Preliminary results from the Cosmic Background Explorer are in, and there
is good news and bad news.  The good news is that COBE has decisively shot
down Berkeley/Nagoya sounding-rocket data which had suggested that the
cosmic background might be warmer than a black body at some infrared
wavelengths that cannot be seen from the grond.  Such extra warmth would
have required "the tooth fairy" to explain it.  However, COBE reports
that the cosmic background is essentially a perfect black body at a
temperature of 2.735 K.  The bad news is that the theorists have been
hoping to see variations in the background from one part of the sky
to another, which would reflect the early density variations that
eventually turned into clusters of galaxies.  Unfortunately, with
preliminary results for 75% of the sky, COBE reports no variations
whatsoever.  If this persists over the full sky with more-accurate
later results, the theorists are in trouble.  (They are already having
some other difficulties, but this would make it much worse.)

[And from the 2 Feb issue of Science:]

The standard explanation of meteorites is that they are debris from the
asteroids.  This is convenient in that it gives us samples of asteroidal
material, albeit very poorly documented ones.  The most common type of
meteorites, the ordinary chondrites, are thought to be derived from the
common type S asteroids.  The material in ordinary chondrites seems to
be primitive material from the early solar system, never exposed to
major heating.  Unfortunately, the spectroscopists have announced
strong evidence that the type-S asteroids are too metal-rich to be
primitive bodies in general, and to be the source of the ordinary
chondrites in particular.  Confusion reigns:  where can the ordinary
chondrites possibly be coming from?  There is some hope that the first
Galileo asteroid encounter, with Gaspra in Aug 1991, might shed some
light on asteroidal geology:  Gaspra is type S.
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 5 Mar 90 21:39:35 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 03/05/90


                              GALILEO
                       MISSION STATUS REPORT
                           MARCH 5, 1990

     The Galileo spacecraft is 50,374,030 miles from the Earth, 6,720,180
miles from Venus and was travelling at a Heliocentric velocity of 90,480
miles per hour. Galileo is in cruise mode-dual spin with a spin rate of
3.15 rpm as measured by its star scanner. The spacecraft's attitude sun point
angle is at 0.5 degrees. Perihelion occurred on February 25. Round trip light
time is 8 minutes, 54 seconds.

     Several SITURNS to lead the sun were successfully performed on February
24, 26, 28 and March 2. Subsequent to the SITURNS performed on February 24
and 26, the attitude control system successfully completed a planned spin
detector calibration. This calibration activity commanded the spacecraft from
the initial dual-spin mode to all-spin and then back to dual-spin. The
spacecraft performance was as expected throughout the calibration activity.

     Several changes were made to the star sets already on
board in the Venus-Earth-1 (VE-1) sequence load. Changes were made to star
sets on February 28 and March 2 to maximize the likelihood of successful star
acquisition. The star updates were made after attitude control identified
serious concern with the on-board star set. Prior to loading the new stars,
extensive analysis and testing was performed. Attitude control star analysts
have completed testing of the remaining stars in VE-1 beyond March 6. All
tests were successful; no further star updates in VE-1 are required.

     Commands were sent on February 26 to change the attitude control
parameters associated with the star scanner bright body avoidance. The
parameter change reduces the half-cone angle stray-light field of view
from about 50 degrees (set at Venus) to about 30 degrees. This change allows
the star scanner to safely and reliably detect the required stars in the
remainder of the VE-1 sequence through March 26.

     On February 26 the system fault protection software was changed to
command selection of the Low Gain Antenna-1 (LGA-1) in the event of execution
of the command loss algorithm. Actual switch from LGA-2 to the LGA-1 is
scheduled for March 12. Performance over the LGA-1 is acceptable for both
command and telemetry as early as March 9. Telemetry performance will be
limited to 10 bps from March 6 thru March 25.

     Cruise Science memory readouts were successfully performed
for the EUV, DDS and MAG instruments as planned.

     AC/DC bus imbalance measurements remain relatively stable. The AC
measurement has varied between 47 and 48.5 volts while DC measurement has
varied between 21.3 and 21.6 volts. All other power-related measurements
(bus voltages, currents, shunt current) and other subsystem measurements
have all been as expected.

     On February 24 the Command and Data Subsystem (CDS) telemetry
indicated that a despun Critical Controller (CRC) Power on Reset (POR) had
occurred. No similar indications were evident elsewhere in the CDS. In fact,
all other CDS telemetry indicators were as expected. The POR signal is generated
by the CDS power converter and sent to the corresponding Hardware Command
Decoder (HCD), and/or spun and despun Critical Controller Circuitry (CRC).
The POR signal is normally generated when either power converter detects a low
voltage condition for several tens of microseconds. No interruptions in
processing or loss of functionality were observed. Once a despun CRC POR
indication is received the logic circuity in the CDS holds that state (via a
latch device) until it is reset by ground command.

     Upon completion of initial anomaly analysis, several real-time command
troubleshooting actions were taken on February 28 and March 2 to determine
whether the POR signal was still present and to reset the POR bit. The first
action verified that the CRC POR bit was still "set" as expected. The
subsequent actions on March 2 POR successfully reset the POR bit and that
the POR related logic circuitry is functioning properly. The success of these
actions provides confidence that the critical controller circuity and
telemetry circuits which monitor this function are working properly. The
exact cause of this anomaly is unknown and its implications are presently
being assessed.


 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

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

Date: 6 Mar 90 01:53:59 GMT
From: zephyr.ens.tek.com!wrgate!mrloog![e-mail]  (Dan Tilque)
Subject: Space capsules (was Re: space news from Jan 22 AW&ST)

[e-mail] (Henry Spencer) writes:
>
>The G.E. proposal is explicitly a minimal scheme, not an "absolutely first
>class" [translation: gold-plated] one like NASA's.  Major points of note:
>
>    - Reliance on existing technology.  "The thing we plan to do
>    use existing technology in forms and integrations that can be
>    demonstrated on Earth in 2-3 years at a cost of $50-150M."
>    No new launchers:  hardware goes up on Titan 4s and Deltas,
>    people on the shuttle or in Apollo-type capsules, with use
>    of commercial launchers a possibility.  24 launches in 10 years.

I'm not sure that Apollo-type capsules can be considered existing
technology, unless they're Russian capsules.  Also, I don't think any of
the current expendables are man-rated (I'm sure someone will correct me if
I'm wrong).

However, they could probably build a capsule for, say 4 people, which
could go up manned in the shuttle payload bay.  If they equip it with
retros, shielding and a parachute, it could double as an emergency
return vehicle.

---
Dan Tilque    --    [e-mail]

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

Date: 6 Mar 90 14:23:22 GMT
From: samsung!brutus.cs.uiuc.edu!ux1.cso.uiuc.edu!uxh.cso.uiuc.edu![e-mail]  (John E. Prussing)
Subject: Re: Rocket Info

In article <[e-mail]> [e-mail] (James Kolasa) writes:
>
>I'm preparing a simple programming assignment for my students and I wonder
>if someone could give me some figures.  Does anyone have a rough estimate of
>mass of a rocket (esp. Saturn V)?  How about fuel capacity?  How about
>a conversion factor between kilograms of fuel and thrust (in Newtons)?
>--
>--   James Kolasa                |      "Computers are so naughty,           --
>--   121 Moloney, L.C.C.         |          I could just pinch them"         --
>--   Lexington, Ky.  40506-0235  |                   -The Martian            --
>--   [e-mail]   {rutgers,uunet}!ukma!jkolasa   [e-mail] --

The thrust of a rocket engine is equal to the PRODUCT of mass flow rate
The thrust of a rocket is equal to the PRODUCT of mass flow rate
(kg/s) times exhaust velocity (m/s). There is no direct conversion
between kg of propellant and thrust.  A modern chemical rocket has
an exhaust velocity of about 4400 m/s.  The shuttle main engines
(of which there are 3) each have a thrust of 1.7 x 10^6 N, and
the solid rocket boosters (of which there are 2) each have
a  thrust of 12.9 x 10^6 N.  From the thrust values and exhaust
velocity given, you can determine the required mass flow rate.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
John E. Prussing                             Internet: [e-mail]
Aeronautical & Astronautical Engineering
University of Illinois at Urbana-Champaign    Bitnet: jep@uiucuxh

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

End of SPACE Digest V11 #120
*******************