Heaviest shuttle payload weight questions
Philip Sloss
and I read that Chandra + IUS is close to the record.
(I imagine this gets asked a Iot, but I couldn't find any specific threads
in DejaNews on this; is there an FAQ with this info?)
1. What is the heaviest payload (orbiter + cargo) that has been put in orbit
by the shuttle -- post OMS-2?
2. What is the maximum orbiter landing weight? (Is it orbiter-specific or
mission-specific? How close would STS-93 come to that if an abort
occurred?)
3. What is the heaviest payload currently in the manifest? Will that and
other flights require higher main engine throttles than 104%?
Thanks,
Philip Sloss
Mike Dicenso
On Sat, 19 Jun 1999, Philip Sloss wrote:
> I thought I'd lump these questions together since they're somewhat related
> and I read that Chandra + IUS is close to the record.
>
> (I imagine this gets asked a Iot, but I couldn't find any specific threads
> in DejaNews on this; is there an FAQ with this info?)
>
> 1. What is the heaviest payload (orbiter + cargo) that has been put in orbit
> by the shuttle -- post OMS-2?
That would be STS-41/Discovery/Ulysses/PAM-IUS. The payload weight was
approximately 48,800 lbs. OV/cargo weight post OMS was 259,593 lbs.
> 2. What is the maximum orbiter landing weight? (Is it orbiter-specific or
> mission-specific? How close would STS-93 come to that if an abort
> occurred?)
I'am not sure what you mean here. Do you mean launch weight, or do you
mean weight at the end of a nominal mission?
> 3. What is the heaviest payload currently in the manifest? Will that and
> other flights require higher main engine throttles than 104%?
STS-93. All other flights for the most part are manifested for ISS. Some
of those ISS missions will require the SSMEs to be set on 106%. They need
to carry the maximum possible payload to ISS' 51.6 inclination.
-Mike
joeh...@pinehurst.net
On Sat, 19 Jun 1999 18:45:17 -0700, "Philip Sloss" <blu...@europa.com>
wrote:
>I thought I'd lump these questions together since they're somewhat related
>and I read that Chandra + IUS is close to the record.
>
>(I imagine this gets asked a Iot, but I couldn't find any specific threads
>in DejaNews on this; is there an FAQ with this info?)
>
>1. What is the heaviest payload (orbiter + cargo) that has been put in orbit
>by the shuttle -- post OMS-2?
>2. What is the maximum orbiter landing weight? (Is it orbiter-specific or
>mission-specific? How close would STS-93 come to that if an abort
>occurred?)
>3. What is the heaviest payload currently in the manifest? Will that and
>other flights require higher main engine throttles than 104%?
>
>Thanks,
>
>Philip Sloss
>
>
>
Jacques van Oene
> > mission-specific? How close would STS-93 come to that if an abort
> > occurred?)
>
> mean weight at the end of a nominal mission?
The Shuttle mission that had the highest landing weight to date was
STS-57 (Endeavour,
Eureca retrieval) with a landing weight of 244000 pounds.
Jacques :-)
Please visit my Spaceflight History homepage at:
http://www.angelfire.com/fl/Jacqmans/
And for Dutch speaking readers this site might be of interest:
Brian Thorn
wrote:
>> 1. What is the heaviest payload (orbiter + cargo) that has been put in orbit
>> by the shuttle -- post OMS-2?
>
>That would be STS-41/Discovery/Ulysses/PAM-IUS. The payload weight was
>approximately 48,800 lbs. OV/cargo weight post OMS was 259,593 lbs.
According to Jenkins...
STS-51L: 48,633 lbs. TDRS-2, SPARTAN-HALLEY (Challenger disaster)
STS-43: 46,712 lbs. TDRS-5, SHARE-II
STS-6: 46,662 lbs. TDRS-1
STS-54: 46,540 lbs. TDRS-6, DXS
STS-41: 46,173 lbs. ULYSSES
Brian
Jerry Aguirre
Brian Thorn <bth...@airmail.net> wrote:
>STS-51L: 48,633 lbs. TDRS-2, SPARTAN-HALLEY (Challenger disaster)
So, your saying that the heaviest payload ever carried was the one
that crashed? No one ever mentioned payload weight as a factor but
it is still interesting.
Brian Thorn
But since the Shuttle gained weight overall as a result of improvements after
the accident, there have been heavier Shuttles since 51-L, just not heavier
payloads.
Brian
Mike Dicenso
On Mon, 21 Jun 1999, Brian Thorn wrote:
> On Sat, 19 Jun 1999 20:06:29 -0700, Mike Dicenso <mdic...@seds.lpl.arizona.edu>
> wrote:
>
> >> 1. What is the heaviest payload (orbiter + cargo) that has been put in orbit
> >> by the shuttle -- post OMS-2?
> >
> >That would be STS-41/Discovery/Ulysses/PAM-IUS. The payload weight was
> >approximately 48,800 lbs. OV/cargo weight post OMS was 259,593 lbs.
>
> According to Jenkins...
>
> STS-51L: 48,633 lbs. TDRS-2, SPARTAN-HALLEY (Challenger disaster)
> STS-43: 46,712 lbs. TDRS-5, SHARE-II
> STS-6: 46,662 lbs. TDRS-1
> STS-54: 46,540 lbs. TDRS-6, DXS
> STS-41: 46,173 lbs. ULYSSES
>
Obviously the Space Flight Reporter's notebook is in disagreement with Mr.
Jenkins, and most suprisingly you left out STS-41D, which was the record
holder until STS-61B flew. So here are my alternates...
STS-51L: 52,308 lbs. noted above
STS-41: 48,812 lbs. noted above
STS-34: 48,643 lbs. Galileo/IUS, SSBUV
STS-61B: 48,041 lbs. SATCOM/PAM-DII, Morelos-B/PAM, AUSSAT-2/PAM-D,
EASE/ACCESS
STS-41D: 47,516 Lbs. SBS-D/PAM, Syncom IV-2, Telstar 3-C/PAM, OAST-1
-Mike
Tom
discerned - Inclusion (or, not) of DTO/DSO's, Nominal vs Actual payload,
Cargo Bay only vs inclusion of Cabin payload, extra reactants /
crewmembers whose weight is supposed to be charged to the payload, in
the case of IUS loads - inclusion (or not) of the up to 5000 lb carrier
cradle, ditto the Pam-D and such carriers, & so on.
Mike Dicenso
On Thu, 24 Jun 1999, Brian Thorn wrote:
> >STS-51L: 52,308 lbs. noted above
> >STS-41: 48,812 lbs. noted above
> >STS-34: 48,643 lbs. Galileo/IUS, SSBUV
>
> 45,905 lbs.
>
> >STS-61B: 48,041 lbs. SATCOM/PAM-DII, Morelos-B/PAM, AUSSAT-2/PAM-D,
> >EASE/ACCESS
>
> 42,788 lbs.
>
> >STS-41D: 47,516 Lbs. SBS-D/PAM, Syncom IV-2, Telstar 3-C/PAM, OAST-1
>
> 41,382 lbs.
>
> Those last two especially are some whopping big differences. I wonder what the
> sources of the two wildly different figures are.
Dunno but the 41,382 lbs figure is almost reminicent of the STS-41-D
payload weight before the SSME pad abort forced NASA into combining 41-D's
manifest with at least one other flight's (41-F's) to make up for the
lost time in the schedule. I've seen the 47,500 lb STS-41D payload figure
mentioned before at least once, so I'am assuming that Jenkin's figure is a
gross mistake of some kind, or is the result of some form of payload
accounting not previously used by the other sources.
> Which adds up to 46,228 lbs., or about 300 lbs. more than Jenkins' figure and
> 2,400 lbs. less than your source.
I'll have to pull out my copy of the presskit, which is in storage. But I
did notice along time ago that the weights given in the payload
weight breakdown sometimes do not include the wetmass of the spacecraft
being carried.
> Which adds up to 47,340 lbs., versus 46,173 from Jenkins and 48,812 lbs from
> your source.
Notice that the two sources the NASA presskit, and the Spaceflight
Reporter's Notebook both set the payload weights higher than Jenkins.
Leading me to conclude that Jenkins is in error here for the most part.
The NASA mission archives website lists STS-41 as "Heaviest payload to
date", which is in line with the Notebook's listing.
-Mike
Philip Sloss
Mike Dicenso wrote in message ...
>...The NASA mission archives website lists STS-41 as "Heaviest payload to
>date", which is in line with the Notebook's listing.
>-Mike
>
Do you know what the URL for that website is?
Earlier, I also asked about maximum landing weight -- I'm curious about how
much weight "margin" there is between the maximum payload and the maximum
touchdown weight...I got the impression that this was or is a limiting
factor in the amount of payload that can be carried.
Thanks to everyone who has answered my questions!
Philip Sloss
Brian Thorn
wrote:
>Obviously the Space Flight Reporter's notebook is in disagreement with Mr.
>Jenkins, and most suprisingly you left out STS-41D, which was the record
>holder until STS-61B flew. So here are my alternates...
I left out 41-D (as well as 61-B and STS-34) because none are in the Top 5, per
Jenkins...
>STS-51L: 52,308 lbs. noted above
>STS-41: 48,812 lbs. noted above
>STS-34: 48,643 lbs. Galileo/IUS, SSBUV
45,905 lbs.
>STS-61B: 48,041 lbs. SATCOM/PAM-DII, Morelos-B/PAM, AUSSAT-2/PAM-D,
>EASE/ACCESS
42,788 lbs.
>STS-41D: 47,516 Lbs. SBS-D/PAM, Syncom IV-2, Telstar 3-C/PAM, OAST-1
41,382 lbs.
Those last two especially are some whopping big differences. I wonder what the
sources of the two wildly different figures are.
I dug up the STS-34 Press Kit to get the "official" preflight figures, and this
is from the "Payload and Vehicle Weights" section.
Galileo/IUS (payload bay) 43,980
Galileo support hardware (middeck) 59
SSBUV (payload bay) 637
SSBUV support 578
DSO 49
DTO 170
GHCD 130
IMAX 269
MLE 15
PM 219
SSIP 70
STEX 52
Which adds up to 46,228 lbs., or about 300 lbs. more than Jenkins' figure and
2,400 lbs. less than your source.
And from the STS-41 press kit...
Remote Manipulator System (payload bay) 1,180
Ulysses/IUS/PAM-S (payload bay) 44,024
Airborne Electrical Support Equipment, RTG cooling
system (payload bay) 203
IUS Support Equipment (payload bay) 260
Shuttle Solar Backscatter Ultraviolet Instrument (SSBUV)
(payload bay) 1,215
Chromosome and Plant Cell Division in Space (CHROMEX) 85
Investigations into Polymer Membrane Processing (IPMP) 33
Physiological Systems Experiment (PSE) 132
Radiation Monitoring Experiment-III (RME-III) 23
Solid Surface Combustion Experiment (SSCE) 140
Voice Command System (VCS) 45
Which adds up to 47,340 lbs., versus 46,173 from Jenkins and 48,812 lbs from
your source.
Brian
Dennis R. Jenkins
where the weights listed in my book came from. Each weight listed is the "Cargo
Weight at Liftoff" which is further defined as "Payload-Chargeable Cargo" per the
"Shuttle Flight Data and In-Flight Anomaly List" (JSC document JSC-19413), better
known as the "Green Book" (because it used to be printed with a green cover). This
is the source for most of the detailed numbers in the book.
As everyone reading this thread has discovered, there is a wide variety of
"official" weights for each flight. The NASA Press Releases are probably the most
inaccurate since they are usually prepared on very preliminary data and never
updated. In many cases they are just flat wrong.
Mission summaries, the Green Book, and other sources all count the payload
differently. And the Green Book does not offer a clear explanation of "Payload
Chargeable Cargo" - in most cases however, it is the weight of the satellite,
including the cradle, support equipment, etc., plus mid-deck payloads and the GAS,
if any.
For instance, on 41-D the "Payload-Chargeable Cargo" weight was 41,382 pounds
consisting of SBS/PAM-D (7,383 pounds, deployed weight), TELSTAR/Pam-D (7,507
pounds deployed), and SYNCOM IV-2 (15,196 pounds deployed) for a total deployed
weight of 30,086 pounds. THis is stuff the Orbiter carried and left in orbit. The
other 11,296 pounds of "Payload-Chargeable Cargo" weight was brought back,
consisting of the IMAX camera, and four mid-deck experiments (CFES III, RME, SSIP,
and clouds - a simple Nikon camera with a 105mm lense). This means 41-D was not a
particularly heavy load.
The "Payload-Chargeable Cargo" weight is also what NASA uses in post-flight
performance analysis of the vehicle, so I am pretty certain it is accurate,
although it might not count all the "things" that other people count as payload
(Astronauts, their supplies and equipment, etc.). Most of these items are acounted
for in different line items (as are propellants, RMS, etc.).
Hope this helps,
-dj
BTW, the NASA History Office has just released Tom Heppenheimer's first volume in
the "Official" Shuttle history. It is called "The Space Shuttle Decision: NASA's
Search for a Reusable Space Vehcile" SP-4221. It provides a great deal more of the
political and economic side of the early Shuttle decisions for anybody interested.
Two more volumes are going to follow.
And I am debating updating my book for a third edition following STS-100. I would
enjoy hearing from anybody with reasonable suggestions for improvements, and also
with any corrections.
----------------------
Mike Dicenso
On Wed, 23 Jun 1999, Philip Sloss wrote:
>
> Mike Dicenso wrote in message ...
>
> >...The NASA mission archives website lists STS-41 as "Heaviest payload to
> >date", which is in line with the Notebook's listing.
> >-Mike
> >
>
> Do you know what the URL for that website is?
"http://www.ksc.nasa.gov/shuttle/missions/missions.html"
-Mike
Mike Dicenso
On Thu, 24 Jun 1999, Dennis R. Jenkins wrote:
> For instance, on 41-D the "Payload-Chargeable Cargo" weight was 41,382 pounds
> consisting of SBS/PAM-D (7,383 pounds, deployed weight), TELSTAR/Pam-D (7,507
> pounds deployed), and SYNCOM IV-2 (15,196 pounds deployed) for a total deployed
> weight of 30,086 pounds. THis is stuff the Orbiter carried and left in orbit. The
> other 11,296 pounds of "Payload-Chargeable Cargo" weight was brought back,
> consisting of the IMAX camera, and four mid-deck experiments (CFES III, RME, SSIP,
> and clouds - a simple Nikon camera with a 105mm lense). This means 41-D was not a
> particularly heavy load.
This is really curious, since the Spaceflight Reporter's Notebook and your
old book "Rockwell International Space Shuttle" (Aerofax Datagraph 5),
both refer to STS-41-D's post SSME abort payload as 47,500 lbs. Just to
bug ya with a ghost from your past let me quote from page 43 of RISS:
"Discovery moments before touching down on runway 17 at Edwards AFB
following STS-14 on September 5 1984. This was Discovery's first flight
and three satellites were deployed. The payload of 47,500 lbs. set a new
shuttle record."
>
> The "Payload-Chargeable Cargo" weight is also what NASA uses in post-flight
> performance analysis of the vehicle, so I am pretty certain it is accurate,
> although it might not count all the "things" that other people count as payload
> (Astronauts, their supplies and equipment, etc.). Most of these items are acounted
> for in different line items (as are propellants, RMS, etc.).
So the 6,118 lbs. difference is being made up for between these two
estimates by what you state above?
> And I am debating updating my book for a third edition following STS-100. I would
> enjoy hearing from anybody with reasonable suggestions for improvements, and also
> with any corrections.
Sure, in RISS you had a beautiful 1/200th scale set of gatefold drawings
covering pages 18-22. I'd dearly love to see you have these drawings
updated to include the new exterior markings for the OV, and the ISS
related mods that have been instituted over the last nine years since RISS
was first published. Since we are now in the ISS era, you might want to
have a special section of the book devoted to how STS will be/is being
used in the construction, and maintenance of ISS.
-Mike
Brian Thorn
>As everyone reading this thread has discovered, there is a wide variety of
>"official" weights for each flight. The NASA Press Releases are probably the most
>inaccurate since they are usually prepared on very preliminary data and never
>updated. In many cases they are just flat wrong.
Thanks for the explanation. NASA does seem to need some standardization about
weights and figures from one source to the next. Even two different mission
press kits differ considerably, such as on the "empty weight" of the orbiters.
>As everyone reading this thread has discovered, there is a wide variety of
>"official" weights for each flight. The NASA Press Releases are probably the most
>inaccurate since they are usually prepared on very preliminary data and never
>updated. In many cases they are just flat wrong.
>Hope this helps,
Do you where will STS-93/AXAF stand in the end, on the total payload weight?
>BTW, the NASA History Office has just released Tom Heppenheimer's first volume in
>the "Official" Shuttle history. It is called "The Space Shuttle Decision: NASA's
>Search for a Reusable Space Vehcile" SP-4221. It provides a great deal more of the
>political and economic side of the early Shuttle decisions for anybody interested.
>Two more volumes are going to follow.
Is it available through Amazon, or do we have to go through the GPO?
>And I am debating updating my book for a third edition following STS-100. I would
>enjoy hearing from anybody with reasonable suggestions for improvements, and also
>with any corrections.
Maybe a few tables listing all of the men and women who flew aboard the first
100, the primary payloads deployed on the first 100, etc.
Brian
Dennis R. Jenkins
Mike Dicenso wrote:
> <stuff snipped>
>This is really curious, since the Spaceflight Reporter's Notebook and your
>old book "Rockwell International Space Shuttle" (Aerofax Datagraph 5),
>both refer to STS-41-D's post SSME abort payload as 47,500 lbs. Just to
>bug ya with a ghost from your past let me quote from page 43 of RISS:
Actually, the first edition of the big shuttle book also contained some conflicting
data. I used to pull the mission reports and use that data. Then I started finding that
they got revised constantly, and contained a lot of conflicting data. Since I got tired
of trying to remember where I had gotten the data, I standardized on the Green Book. As
for the reporter's notebook - like most PR material, it has its own problems.
>So the 6,118 lbs. difference is being made up for between these two
>estimates by what you state above?
I am not real sure there is a 6,118 pound difference. As I said, the press kits and
reporters notebook tend not to be terribly reliable. But whatever difference there is is
probably accounted for by "other" items (such as astronauts).
>Sure, in RISS you had a beautiful 1/200th scale set of gatefold drawings
>covering pages 18-22. I'd dearly love to see you have these drawings
I have been trying to secure permission from Jay Miller (who owned Aerofax, and hence
the drawings) to use them. Actually, he gave me permission, but has never sent the
original drawings. I will bug him again because I would like to include them also.
And I do plan (and will hopefully succeed) to cover ISS in some detail in the next book
(and maybe finish the uncompleted Space Station companion volume that has been sitting
here for six years ;)
Thanks for the comments ...
-dj
Dennis R. Jenkins
Brian Thorn wrote:
<stuff snipped>
>
> Do you where will STS-93/AXAF stand in the end, on the total payload weight?
Not sure. Honestly, I have not been tracking things lately ... sorry.
>
>
> >BTW, the NASA History Office has just released Tom Heppenheimer's first volume in
> >the "Official" Shuttle history. It is called "The Space Shuttle Decision: NASA's
> >Search for a Reusable Space Vehcile" SP-4221. It provides a great deal more of the
> >political and economic side of the early Shuttle decisions for anybody interested.
> >Two more volumes are going to follow.
>
> Is it available through Amazon, or do we have to go through the GPO?
Probably only through GPO. I am not sure how much it will cost (it is a hardcover with
dust jacket), but it is probably worth it if you are into Shuttle. I just received
mine (courtesy copy) and have not really sat down and looked at the final product yet.
>
>
> >And I am debating updating my book for a third edition following STS-100. I would
> >enjoy hearing from anybody with reasonable suggestions for improvements, and also
> >with any corrections.
>
> Maybe a few tables listing all of the men and women who flew aboard the first
> 100, the primary payloads deployed on the first 100, etc.
This should be easy (if I can find the page count). The "Green Book" keeps running
totals on all sorts of trivia in this regard!
Thanks for the suggestions.
-dj
Mike Dicenso
On Fri, 25 Jun 1999, Dennis R. Jenkins wrote:
> I am not real sure there is a 6,118 pound difference. As I said, the press kits and
> reporters notebook tend not to be terribly reliable. But whatever difference there is is
> probably accounted for by "other" items (such as astronauts).
Ultimately it sounds like a "pick and choose" question. I can understand
why you'd want to go with the conservative numbers of the Green Book.
>
> >Sure, in RISS you had a beautiful 1/200th scale set of gatefold drawings
> >covering pages 18-22. I'd dearly love to see you have these drawings
>
> I have been trying to secure permission from Jay Miller (who owned Aerofax, and hence
> the drawings) to use them. Actually, he gave me permission, but has never sent the
> original drawings. I will bug him again because I would like to include them also.
It'd be a big pain in the A** to have to re-commission a whole new set of
drawings. Then again you'd almost have to do that anyway to show the new
"Meatballed" OV markings, and the elimination of the black optical
tracking markings.It's probably been pointed out already, but on page 20
of the RISS gatefold illustration, the HRSI tile pattern around Atlantis'
ingress/egress hatch is the same as Challengers. It should actually be
more like Discovery's, or Endeavour's.
> And I do plan (and will hopefully succeed) to cover ISS in some detail in the next book
> (and maybe finish the uncompleted Space Station companion volume that has been sitting
> here for six years ;)
I'd buy that for a dollar!
-Mike
Mike Dicenso
On Fri, 25 Jun 1999, Dennis R. Jenkins wrote:
>
>
> Brian Thorn wrote:
>
> <stuff snipped>
>
> >
> > Do you where will STS-93/AXAF stand in the end, on the total payload weight?
>
> Not sure. Honestly, I have not been tracking things lately ... sorry.
An Av Week article that I read placed STS-93 at somewhere just above
50,000 lbs. I can believe it too considering just how heavy Chandra, and
the IUS alone are (32,000 lbs + 11,000 lbs = 43,000 lbs). Add in a 5,000
to 7,000 lbs. IUS support tilt table and other support equipment and your
just about hitting, or excedding the 50,000 lbs. mark. Now what would be
interesting would be finding out the payload weight of the cancelled
Challenger/51-E mission. That was supposed carry TDRS-B/IUS and and an
Anik comsat. Everything was loaded and ready to go when problems cropped
up with the TDRS-B, and the whole thing had to be scrapped. Challenger had
to reconfigured and remanifested for the STS-51-B/Spacelab 3 mission.
-Mike
Tom
>
> On Thu, 24 Jun 1999 20:05:20 -0400, "Dennis R. Jenkins" <djen...@Iu.net> wrote:
>
> >enjoy hearing from anybody with reasonable suggestions for improvements, and also
> >with any corrections.
>
> Maybe a few tables listing all of the men and women who flew aboard the first
> 100, the primary payloads deployed on the first 100, etc.
In your first book, you had a lot of extensive ET propellant loading
info. I would like to see specific similar information on the SRB's. I
would also like to see the ET weights dry and as jettisoned. Same for
the SRB's.
Additionally, how about at least one SRB thrust-time curve. Maybe one
from the original 294 Mln lb-sec SRBs with an Isp of 265.5 and the later
298.4 Mln lb-sec SRBs with an Isp of 268.6
Jacques van Oene
> Challenger/51-E mission. That was supposed carry TDRS-B/IUS and and an
> Anik comsat. Everything was loaded and ready to go when problems cropped
> up with the TDRS-B, and the whole thing had to be scrapped. Challenger had
> to reconfigured and remanifested for the STS-51-B/Spacelab 3 mission.
> -Mike
In aviation week of February 18, 1985 there is an article about STS-51E.
It list the weight of the TDRS and IUS tilt table and mid-payload-bay
support brace at a total of a little more than 44,800 pounds. The weight
of the Anik C-1 com-sat is not given in the article, but in the press
kit of STS-51D the weight of the Anik-C1 is 7,386 pounds and the
pallet-attach structure for Anik-C1 is 2,406 pounds if you add those to
the weight of the TDRS and IUS you come to the total of 54,592 pounds
for STS 51E. In Aviation week of February 18, 1985 they list the maximum
payload a Shuttle can carry to orbit as 65,000 pounds.
Jacques :-)
please visit my spaceflight history homepage at:
David K Cornutt
> Earlier, I also asked about maximum landing weight -- I'm curious about how
> much weight "margin" there is between the maximum payload and the maximum
> touchdown weight...I got the impression that this was or is a limiting
> factor in the amount of payload that can be carried.
There are a couple of limiting factors having to do with weight.
As you might suspect, if 65,000 lbs. is still the max allowed payload
weight at takeoff, then there is actually negative margin between
the takeoff weight and the maximum nominal end-of-mission landing
weight. An empty Orbiter weighs about 180,000 lbs (except
Columbia which is about 9000 lbs heavier), and probably the
minimum "curb weight" that an Orbiter would ever land with,
allowing for the fact that it is going to land with crew and
at least some propellant and reactant remaining (not to
mention leftover water, ammonia for the ammonia boilers, etc.,
plus things like crew trash) is probably about 185,000 lbs.
That leaves about 45,000 lbs margin between that weight and
the max nominal landing weight of 230,000 lbs. In the case
of a very heavy payload such as a satellite, if it couldn't
be launched, it would have to be jettisoned and left in orbit
in order to meet the max landing weight. Permissible abort
weight is higher at 248,000 lbs, which pretty much covers
any payload (but I'll bet that at some of the abort sites it
would be really iffy as to whether the Orbiter could stop
within the length of the runway).
There is another factor to be figured in landing weights, which
is the Orbiter front-to-back center of gravity. A CG further
forward at landing puts additional stress on the nose gear
when it touches down. Because of this, there are some
restrictions on choice of landing sites with a heavy Orbiter.
In particular, if the weight is near the 230,000 limit and
the CG is forward, then the Edwards lakebed runways are
disqualified because the heavy sand puts drag on the wheel
and hence more stress on the nose gear. This could cause a
real problem: if on a day when both KSC and the Edwards 04/22
concrete runway were unavailable (quite possible if, say there
are storms at KSC and the wind is wrong at Edwards), then if
the Orbiter had to land that day it would have to land at
White Sands. It becomes even more of a problem when an abort
landing is considered; if an Edwards AOA landing were necessary,
and 04/22 had a bad crosswind, there would be a Faustian
choice between landing on 04/22 and risking the crosswind,
or landing on the lakebed and facing a probable nose gear
collapse. And unfortunately, because of where the payload
bay is, large and heavy payload loads usually move the CG
forward. Considerations like this tended in particular to
limit the payload weights on e.g. Spacelab missions (the
necessary positioning of the lab modules usually resulted
in a forward CG).
(There are also flight controllability issues associated
with a forward CG, but I think the landing weights are the
more limiting case.)
--
David K. Cornutt, Residentially Engineered, Huntsville, AL
Solving the Eternal Question: "Who is Kimberly Morris, and how
did she get her own exit on Interstate 65?"
Mike Dicenso
Thanks, I'd just looked up the issue for myself when I saw your posting.
There were also secondary in-cabin payloads that would've brought the
weight at, or just above the 55,000 lbs. mark if your estimate is correct.
Just one more of those fustrating "might've beens"....
-Mike
Dennis R. Jenkins
Tom wrote:
>
> In your first book, you had a lot of extensive ET propellant loading
> info. I would like to see specific similar information on the SRB's. I
> would also like to see the ET weights dry and as jettisoned. Same for
> the SRB's.
In the second edition (brown cover) of the book, pages 302 and 303 lists everything I
think you are asking for. I list the serial number for each SRB, its ignition weight,
its jettison weight, the usable propellant, max thrust, burn time, and motor/casing
type. I also list the type of ET (from which you can determine its nominal dry weight)
and the resilual propellats at jettison (from which you can derive the jettison
weight).
Let me know if there was something else you had in mind.
>
>
> Additionally, how about at least one SRB thrust-time curve. Maybe one
> from the original 294 Mln lb-sec SRBs with an Isp of 265.5 and the later
> 298.4 Mln lb-sec SRBs with an Isp of 268.6
Good suggestion. I'll work on that one.
Tom
touchdown weight over 230,000 lbs:
Mission Touchdown Wt CG X-Loc
STS-73 230,469.3 lb 1082.0 in
STS-83 230,276.3 lb 1081.3 in
STS-94 230,283.5 lb 1080.0 in
Philip Sloss
I seem to recall reading or hearing that on one of the heavier landings (a
Spacelab module flight) that they preferred landing at a higher speed with
heavier weight, but maybe that was also forward CG...wasn't the LDEF
retrieval (STS-32) a flight with a relatively forward CG?
Any ballpark number on what the STS-93 landing weight would be with Chandra
still in the payload bay? I imagine that the IUS keeps the CG aft, but they
would only land with it in an abort scenario so RCS propellant weight and
potential propellant dumps would also come into play...
Thanks again,
Philip Sloss