Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_0/v16no069.txt

Internet Message Format | 1993-07-13 | 23.1 KB

Date: Thu, 21 Jan 93 05:17:22
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #069
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 21 Jan 93       Volume 16 : Issue 069

Today's Topics:
                 A question about mercury and Gemini.
 AUSROC II launch fails, but commitment to project continues (Dec 92)
             Making Orbit 93 - Collected Papers Available
             Making Orbit 93 - The Delta Clipper Program
                          Mars Observer TES
      Sabatier reactor? (was Re: Oxygen in Biosphere 2) (2 msgs)

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 20 Jan 93 07:23:00 EST
From: Chris Jones <[e-mail]>
Subject: A question about mercury and Gemini.
Newsgroups: sci.space

In article <[e-mail]>, prb@access (Pat) writes:
>Now these systems had escape rocket towers for abort safety, but
>they would be jettisoned 1-2 minutes into flight.

Mercury had an escape rocket.  Gemini had ejection seats.

>                            My question,
>is if you have already paid the penalty, to carry the tower,
>why not keep it as an emergency retro-rocket, in case the main
>retro-roket failed?

Once you drop the escape tower, you stop paying the penalty, and they were, as
you say, dropped pretty early.  Any weight you shed while under thrust is a net
win.  (Of course, on Gemini they carried the seats all the way back into orbit
and back to earth).  I expect they designed the escape rocket for its intended
purpose and kept it as simple as possible.  Giving it two life-or-death
missions would seem to me to increase the chances it would fail when needed.

>              granted the performance of the escape
>tower would have to be improved to match the main package,
>but were teh retros already fail-safe?   seems like they were
>awful sure.

The retro-rockets had a lot of redundancy built into their systems.  They were
as sure as they could be that the retros would work.  On Gemini, on at least the
first manned flight, they also lowered the orbit prior to the retrofire so that
even without retrofire the spacecraft would have reentered in an orbit or two.

Martin Caidin's book _Marooned_ (the one concerning Mercury, not the one
released for the movie) had as its premise that a Mercury capsule was stranded
in orbit due to its retrorockets failing to fire.  He didn't explain what
failure could have caused this, and did go into the redundancy of the system
quite a bit while showing the puzzlement of the engineers trying to understand
what had happened.
--
Chris Jones    [e-mail]

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

Date: 20 Jan 93 03:35:41 GMT
From: [e-mail]
Subject: AUSROC II launch fails, but commitment to project continues (Dec 92)
Newsgroups: sci.space

Reprinted from CSIRO Space Industry News, No. 49, p. 5, December 1992.

AUSROC II launch fails, but commitment to project remains
---------------------------------------------------------

     AUSROC II, a key component of the Australian Space Engineering and Research
Association's (ASERA) amateur rocket program, failed to leave the ground when
fired at the Woomera Rocket Range on Thursday 22 October.

     Owing to a faulty liquid oxygen valve, the vehicle caught fire and was
extensively damaged. Project organisers say that the motor, injector, and
recovery system may be salvageable, but that new oxygen and kerosene tanks, and
a new structure will be required.

     Also salvageable is the participants enthusiasm for the project. They are
currently reviewing the vehicle's systems with a view to modifying the design
and the launch operations, and the launch of an improved AUSROC II has been
tentatively scheduled for September 1993.

     An AUSROC II post mortem was the first item on the agenda at the Second
Annual AUSROC Conference, held at the University of South Australia - Levels
Campus, on 9-11 December. Also at the conference, there was detailed discussion
of systems development for AUSROC III, a planned suborbital vehicle, and
AUSROC IV, on which the group hopes to eventually place a microsat in orbit.
There are currently over 40 volunteers from a range of institutions involved in
the development of AUSROC III systems.

     The AUSROC rocket program started in 1988 when a group of Monash University
students and amateur rocketeers united to design and construct a small, fuelled
rocket, based upon a design from the Pacific Rocket Society in the USA. This
rocket - AUSROC I - was launched from the Graytwon Proof and Experimental
Establishment, Victoria.


Previous AUSROC updates can be obtained by anonymous ftp to
audrey.levels.unisa.edu.au in directory space/AUSROC

--
Steven S. Pietrobon,  Australian Space Centre for Signal Processing
Signal Processing Research Institute, University of South Australia
The Levels, SA 5095, Australia.     [e-mail]

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

Date: Thu, 21 Jan 1993 00:42:37 GMT
From: Bruce Dunn <[e-mail]>
Subject: Making Orbit 93 - Collected Papers Available
Newsgroups: sci.space

I attended the "Making Orbit 93" conference held in Berkeley over the January
16 weekend.  I had a great time, learned much, and met many people who I knew
by reputation or E-mail, but whom I had never met.  The total attendance
might have been something like 75 or 100 - small enough so that meaningful
discussions could be held.

The conference was about 75% rocket science (focusing on alternatives to the
Shuttle and conventional launchers for reaching orbit), and about 25% science
fiction (including the participation of both Larry Niven and Jerry
Pournelle).  I didn't manage to attend the full conference, and had to leave
Sunday afternoon as I had 110 university students waiting for a lecture at
8:30 Monday morning (no Martin Luther King holiday in Canada).  Also, the
conference ran parallel sessions so that nobody could hear everything.  I
concentrated on the launcher concepts - I will be posting some material
related to talks that I did attend.

Congratulations are due to David and Terry Berry who organized the
conference, and to Henry Vanderbilt who organized the program.

For those not familiar with the content of the conference from pre-conference
publicity, I reproduce below some of the titles of talks:


Alternative SSTO Design Approaches - Jurmaine  (General Dynamics)

Clementine (lunar survey spacecraft) - Kare

Delta Clipper  - Gaubatz (head of McDonnell-Douglas SSRT program)

The "Frequent Flyer" Space Plane Project - Gary Hudson (orbital launch via a
composite spaceplane)

The Japanese Mars Program - Shimizu (mars probes)

Laser Launch - Kare

Perestroika in the US Space Industry - Can Commercial Activity Take up the
Slack - Bennett

Power for Lunar Surface Applications - Mayer

Rocket Science for Amateurs - Cobb, Vanderbilt

Soviet/CIS Space Launcher Characteristics - Bozlee

Space Launch by Gas Gun - Hunter

Space Policy 2000 Prime - Graham

The SSTO Operational Environment - Stine   (economics etc.)

A Storable Propellant SSTO - Burnside Clapp


In addition to these talks, there were numerous panel discussions.

Bill Nicholls will be organizing and producing a collection of papers given
at the conference.  To quote Bill:

"This is intended to be a best efforts collection of electronic and written
materials for sale subsequent to the conference....    Availability of the
final product is 2 to 3 months after the conference.    While we plan to
incorporate photos taken at the conference and any available transcripts, I
want to make it clear that we do not expect to have a complete record of the
conference, especially the panel sessions.  Any profits from sale of the
"Collected Papers" will be returned to Henry's [Vanderbilt, not Spencer]
SPACE ACCESS organization."

The pre-publication price for the collected papers is $15  US.  To order,
send money, name, and address to:

Bill Nicholls
PO Box 28
Roy, WA 98580

The order form that I have in front of me indicates that the deadline for
orders at the pre-publication price is January 31, 1993






--
Bruce Dunn    Vancouver, Canada   [e-mail]

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

Date: Thu, 21 Jan 1993 03:51:36 GMT
From: Bruce Dunn <[e-mail]>
Subject: Making Orbit 93 - The Delta Clipper Program
Newsgroups: sci.space

I recently attended the "Orbit 93" conference in Berkeley.  The following are
notes I made at the presentation "Delta Clipper"  by Bill Gaubatz, head of
the SSRT program at McDonnell Douglas.  The presentation was given using
professionally prepared view-graphs from MacDonnell Douglas, many of which
were marked "competition sensitive" (presumably reflecting the preparation of
the view-graphs before MacDonnell Douglas won the contract for the DC-X test
vehicle).



Delta Clipper vehicle:

The following comments refer to the "Delta Clipper" (name used during the
talk) or DC-1 (name used on the net), the eventual product of a development
program involving a DC-X technology demonstrator and a DC-Y prototype.

Planned capability is 16,000 lbs to a 220 nautical mile orbit, 25,000 lbs to
an unspecified LEO (low earth orbit).

Vehicle is roughly three times as long as it is broad.  The upper end is
bullet like, becoming wider towards the base.  The cross section is circular,
except at the base where the four main engines give the shape of a round
edged square. In addition to the four main engines, there are four smaller
engines.  Engine type was not specified in the view-graphs.

The vehicle burns hydrogen and LOX, and has a cargo bay at mid-vehicle.  The
cargo bay is 15x15x30 feet, and has a door to the side of the vehicle.  The
cargo is supposed to be put into a standard container, and loaded into the
cargo bay using a simple ground-based scissors jack.  The standard container
will have power, coolant, and data transfer connections for maintaining the
health of the payload.

Gaubatz says the vehicle is "people capable", a term which he prefers to "man
rated" which he implies is a term which should be used only for older style
launchers.

The vehicle has large design margins based on current aircraft practice, so
that the vehicle will have a long lifetime.

The vehicle will have "reliability centered maintenance", a buzz term which
was not particularly clearly defined by Gaubatz.

Gaubatz says that for design work, MacDonnell Douglas has brought together
people with rocket skills (from their Delta commercial vehicle group) and
airplane skills (from their aircraft group).   In reply to a question from
the audience, he stated that the group was about 60% rocket people, and about
40% aircraft people.

The total launch crew in the "flight operations center"  (he points out that
"blockhouse" is not appropriate) is 3 people; a "flight operations manager"
and deputy, and a ground operations controller.  Drawings show something like
a control tower for operations, with no provision for protection against
explosions.

Ascent to orbit will involve a burn of 369 seconds, with a maximum G loading
of 3.0  The vehicle will have engine out capability at any time in flight.
On ascent, once past 60,000 feet (about 9 miles downrange) the vehicle will
pass out of FAA control - prior to this FAA clearance will be used.

The vehicle enters nose first.  The re-entry aerodynamics of the vehicle are
derived from the very large body of data which is available on missile
warhead re-entry aerodynamics.   The angle of attack of the vehicle is
controlled to minimize thermal loading.  The vehicle has a 1200 to 1500
nautical mile cross range.  Deacceleration is 1.1 g maximum during descent.
On descent, the vehicle goes subsonic at 60,000 feet altitude, and the
engines are then started and idled.  At 5000 to 10,000 feet altitude, the
vehicle is rotated base down. 2 engines are powered up to deaccelerate and
land the vehicle (note that the other two main engines are idling, and can be
powered up if needed).  The vehicle will land on a pad using retractable
landing gear.  Wheels will be attached to the landing gear, and the vehicle
rolled over to a "flight stand". After placement on the flight stand (which
takes the weight of a fueled vehicle), the vehicle will be given a new
payload, fueled, and reflown. Gaubatz notes that the noise footprint for a
vertical takeoff and landing is more restricted than the noise footprint for
a horizontal takeoff vehicle.

Most maintenance is projected to take place on the flight stand - in normal
circumstances a 12 hour turnaround is expected.  Minor maintenance with "line
replaceable units" will take less than 24 hours, while major maintenance
involving interior components such as fuel cells will take place in less than
1 week at an adjacent hanger.  Once a year, the vehicle will undergo a 30 day
maintenance and certification.

Gaubatz notes that the launch organization for the existing commercial Delta
expendable launcher involves 320 people, who can send off 12 flights per
year. He claims that this is the most efficient launch organization in the
US.  He claims that the same number of people will be able to support 4 to 5
Delta Clipper vehicles, each flying 40 times per year.  He further notes that
for expendable launchers, two thirds of the cost  of a launch is for the cost
of the expended hardware.



DC-X vehicle:

The following comments refer to the DC-X experimental vehicle, currently
being built by MacDonnell Douglas for proof of concept testing:

The DC-X program is a 2 year program, costing about $60 million.  Gaubatz
states that were the program handled in the "usual NASA manner" it would have
been a $ 1000 million program, taking 5 to 8 years.

The DC-X is similar in shape to the final Delta Clipper, but one third scale.
The hydrogen tank is on the bottom of the vehicle, while the oxygen tank is
on the top.  The nosecone and tail of the vehicle is being built of composite
material by Burt Rutan, of Scaled Composites. The interior of the hydrogen
tank is lined with balsa wood bonded to the metal (no- this is not a typo).
All avionics are off-the-shelf from current aircraft instrument
manufacturers.

The vehicle is not designed to go above about 30,000 feet and does not carry
enough fuel to get to orbit.  MacDonnell Douglas however seems to be thinking
about using the DC-X as a reusable sounding rocket after testing is finished
("SOAR" = Sub Orbital Applications Rocket").  The vehicle is unmanned, and is
flown by computer with links to ground control.  The major objective of the
flight testing is to verify the design tools and assumptions used, in order
to demonstrate the feasibility of the McDonnell approach to building an SSTO.

Vehicle engines are an RL-10 derivative with a reduced expansion ratio for
atmospheric flight.  Isp at ground level is 337, and the engine can be idled
at about 10% power, and run at any setting between  30% to 100 % power (3700
to 13500 lbs force).  Only 30% power is required for landing.  The first
engine tested already has "a couple of hours" of run time (impressive for an
engine originally designed as a throw-away item which only had to run for a
few minutes).   Considerable testing has been done to demonstrate "snap
throttling", or very rapid changes in engine power.  There are probably 4
engines (the viewgraph was confusing so I am not certain on this point).  The
RCS (Reaction Control System) runs on gaseous hydrogen and gaseous oxygen,
and is in a replaceable module in the base of the vehicle between the
engines.  The top of the vehicle has a compartment for a parachute, for a
"belt and suspenders" approach to getting the vehicle back in one piece.  The
top of the vehicle also has GPS receivers.

The vehicle is launched by a 3 person crew in a trailer (flight operations
manager, deputy, and ground operations controller).  Total testing crew will
be 35 people.  Testing will be from WSSH, or "White Sands Space Harbor",
starting in late May of this year at the White Sands Missile Range in New
Mexico.  Some provision will be made for the public to watch the testing -
arrangements are not yet firmed up but will be publicized when available.
Gaubatz notes that the White Sands people have been very co-operative.
Gaubatz wants to test at White Sands to "get away from the current launch
culture" (presumably represented by NASA).  The vehicle will not carry a
destruct package - something that Gaubatz regards as a  victory over the
existing launch culture and a demonstration of the reasonableness of the
White Sands range safety people.

Landing gear of the vehicle is retractable, and made by MBB (Deutsche
Aerospace, in Germany).  The landing gear is designed for up to a 7 G
landing, and rough field capability is designed in.  The landing gear is
retracted during takeoff, and only deployed in the terminal phase of landing.

 Flight software is designed as much as possible to be the same software that
would be used in controlling the final Delta Clipper vehicle.  The software
is being written in ADA, and is ahead of schedule and under cost.  Gaubatz
says "If I could build the whole vehicle out of software, I would".  The
flight operations control screens are designed to look like a "glass cockpit"
in a modern airliner.  Items displayed on the screen can be "clicked on"
(presumably with a mouse) to display further information.

Gaubatz is "fully anticipating overall success".  Burt Rutan figures that the
simplest approach to flight control is to put a pilot on board the vehicle.
One of the flight controllers (operating a computer console on the ground)
will be Pete Conrad.  Gaubatz states that Conrad has been eyeing the
parachute compartment in the DC-X, and hinting that if the parachute were
removed, there would be room for a pilot!

--
Bruce Dunn    Vancouver, Canada   [e-mail]

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

Date: Thu, 21 Jan 1993 04:00:27 GMT
From: Steve Collins <[e-mail]>
Subject: Mars Observer TES
Newsgroups: sci.space

I went to a breifing today by Thermal Emission Spectrometer (TES) folks.
They are working to get some instrument calibrations done before we get to
Mars and gave a wonderful overview of their instrument and science objectives.

It was really an exciting presentation,
It was really an exciting presentation. The TES can produce very detailed
infrared spectra with enough spatial resolution to correlate them to
geologic features. Since different minerals have distinct IR absorption
signatures, they will be able to do detailed mineralogy from orbit!
They will also use TES to study atmospheric phenomona and the polar ice
caps. Most of the Mars minerology and geochemistry data to date is based
on assumptions about similarities to Earth. Now we will be able to make
a map that says Basalt over here and Limestone over there...
If there is limestone. One of the big questions is whether there was
substatial
water (oceans!) in Mars' early history. If so there may be evidence in
the form of Salt deposits and limestone. This would be the place to
go looking for fossils, since (on earth at least) there was life in the
oceans fairly early on. I

Keep an eye out for TES results in journals near you...W~r

          Steve Collins  MO Spacecraft Team (AACS)

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

Date: Thu, 21 Jan 93 00:18:49 GMT
From: John Finn <[e-mail]>
Subject: Sabatier reactor? (was Re: Oxygen in Biosphere 2)
Newsgroups: sci.space

In article <[e-mail]> Frank Crary,

[e-mail] writes:
>In article <[e-mail]> [e-mail]
(Bill
>Higgins-- Beam Jockey) writes:
>>Pat, could you explain, for the benefit of chemical engineering
>>illiterates, what the heck is the "sabatier" reaction and how you can
>>make a chemical reactor gadget so small?
>
>It's a chemical process that, as I recall, uses heat and a few
>catalists to convert carbon dioxide into oxygen and waste cardon.
>There are one or two other artificial processes that do the same
>thing, but the sabatier process (apparently) has some advantages
>in terms of size, effecience, etc... A fair amount of research has
>gone into it, and it's a common part of closed or partially closed
>spacecraft life support systems. (The shuttle doesn't use it, since
>the oxygen carried versus sabatier machinery trade off favors open
>life support systems for missions under a few weeks... But I think
>Freedom is supposed to use it.)

There are two mature physical/chemical technologies for CO2 reduction:
Bosch and Sabatier. The Sabatier design for life support systems in space
is several times smaller, lighter, and energy efficient than Bosch, and
has been selected for Space Station (when SSF reaches permanently-manned
capability -- no CO2 reduction until then).

I think people have confused the two, so here's a little information:

Bosch:
Manufactured by Life Systems, Inc.
CO2 + 2(H2) => C + 2(H2O)      (solid carbon formation)
conditions: 1040 F on a nickel wool catalyst
full configuration for 8-man crew (4 units + spares, etc.):
     4055 lbs, avg. 1378 watts, 209 cubic feet

Sabatier:
Manufactured by Hamilton Standard
CO2 + 4(H2) => CH4 + 2(H2O)      (methane formation)
conditions: 950 F on a ruthenium/alumina catalyst
full configuration for 8-man crew (4 units + spares, etc.):
     1096 lbs, avg. 395 watts, 34 cubic feet

Of course, one still might want a carbon formation reactor to get the
hydrogen back out of the methane, and that technology is not mature.
Bosch still might make a fair challenge to a Sabatier+carbon formation
reactor.

For many more details and comparisons plus other technologies (if anyone
is interested), find NASA TM 4340, "Space Station Freedom Environmental
Control and Life Support System Regenerative Subsystem Selection", by
Carrasquillo et al. (Marshall Space Flight Center). This information was
taken directly from that report.

John Finn, Ph. D.
Regenerative Systems Branch, Advanced Life Support Division
NASA Ames Research Center
[e-mail]

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

Date: 21 Jan 93 02:11:21 GMT
From: George Michaelson <[e-mail]>
Subject: Sabatier reactor? (was Re: Oxygen in Biosphere 2)
Newsgroups: sci.space

John Finn <[e-mail]> writes:

>Manufactured by Hamilton Standard
>CO2 + 4(H2) => CH4 + 2(H2O)      (methane formation)
>conditions: 950 F on a ruthenium/alumina catalyst
>full configuration for 8-man crew (4 units + spares, etc.):
>     1096 lbs, avg. 395 watts, 34 cubic feet

Does CH4 have any role inside a space station apart from making it
smell farty?

     refrigerant gas?
     cooking :-) yes... I know it makes C02...

Failing which would venting to space or using as supplement to position holding
rocketry be worth the effort?

-George
--
                         George Michaelson
[e-mail] The Prentice Centre      | There's no  market for
                         University of Queensland | hippos in Philadelphia
Phone: [phone]    QLD Australia 4072       |          -Bertold Brecht

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

End of Space Digest Volume 16 : Issue 069
------------------------------