Skylab questions....
Michael M. Ross
What happened to Skylab--did it burn up? Why were there only 3
missions?
Size-wise and technology-wise, how did it measure up to Mir?
(BTW It's curious to me that many people have forgotten/never knew
there was an American spacestation in the 70s...)
--Michael
George Skinner
supposed to be in a stable orbit until ~1982, but NASA didn't realize
that increased solar activity in the 1970's would increase the "drag" of
solar wind on the station. As a result, it came down early.
Skylab's mass was about 100 tons, or close to Mir. Skylab had about
the same amount of livable volume as Mir, but whereas Mir consists of a
bunch of long, narrow modules, Skylab was built out of the third stage
of a Saturn V. Pretty huge compared to Mir.
Its technology was late 1960's vintage Apollo. Mir probably has a
decade or so on that. The Soviet Union launched a series of Salyut
stations in the 1970's, and gained a lot of experience with space
station operations. That's why NASA is cooperating with Russia on ISSA.
Like Mir, Skylab had its share of problems. Most notable was that its
meteoroid shield deployed during launch and tore off, depriving the
station of its protection from solar heating, tearing off one of the 2
main solar arrays and preventing the other from deploying. Skylab's
inertial platforms also started to fail, threatening the station.
NASA planned to fly the shuttle up to Skylab after the 4th or 5th
flight of the shuttle to boost the station to a higher orbit, but the
shuttle was delayed too long. As for only 3 missions to Skylab, I think
that was because NASA didn't have the budget or hardware to do more.
The Saturn V used to boost Skylab and the Saturn IBs used for the crew
were left-overs from Apollo. BTW, a second flight-ready Skylab was
built, but never launched. It is now located in the National Air &
Space Museum.
Frank Crary
In article <33DE84...@gpu.srv.ualberta.ca>,
George Skinner <gski...@gpu.srv.ualberta.ca> wrote:
> Skylab crashed into the Indian Ocean in 1979. It was originally
>supposed to be in a stable orbit until ~1982, but NASA didn't realize
>that increased solar activity in the 1970's would increase the "drag" of
>solar wind on the station. As a result, it came down early.
This isn't quite correct. The drag of the solar wind has no effect
of low Earth orbiting satellites. It's deflected by the Earth's
magnetic fields at between 5 and 10 Earth radii above the surface.
What happened to Skylab was entirely drag from the Earth's atmosphere.
During solar maximum, the flux of ultraviolet light goes up rather
substantially. The UV is absorbed by the upper atmosphere, and, because
the air isn't very dense at those altitudes, this can increase
upper atmosphere temperatures by a significant amount. The density
of a hot gas doesn't decrease as rapidly with altitude. So heating
the upper atmosphere means increasing the gas density in low Earth
orbits, and that means satellite orbits decay faster. We didn't
really know about that in the 1970s, which is why Skylab reentered
sooner than expected.
Frank Crary
CU Boulder
Julian Bordas
George Skinner wrote:
>
> Skylab crashed into the Indian Ocean in 1979.
BZZZZZ Wrong!!
Skylab landed on Western Australia
Juliana
Christopher Michael Jones
Actually, I believe that it is partly correct. It isn't the Solar
Wind per se though. The outer atmosphere sort of ballons due to
increased solar activity.
Frank Crary (fcr...@rintintin.Colorado.EDU) wrote:
: In article <33DE84...@gpu.srv.ualberta.ca>,
: George Skinner <gski...@gpu.srv.ualberta.ca> wrote:
: > Skylab crashed into the Indian Ocean in 1979. It was originally
Del Cotter
On Fri, 1 Aug 1997, in sci.space.tech
Julian Bordas <JBo...@vcrpmrkt.telstra.com.au> wrote
>> Skylab crashed into the Indian Ocean in 1979.
>
>BZZZZZ Wrong!!
>
>Skylab landed on Western Australia
Actually, I think both statements could be true: that's Skylab all over.
--
Del Cotter d...@branta.demon.co.uk
The US Tour Sat 23rd August - Sun 14th September 1997
Houston SanAntonio Phoenix Flagstaff GrandCanyon LakeMead LasVegas
DeathValley Yosemite NapaValley SanFrancisco TouristTipsGratefullyReceived
Aaron Gilliland
Julian Bordas wrote:
>
> George Skinner wrote:
> >
> > Skylab crashed into the Indian Ocean in 1979.
>
> BZZZZZ Wrong!!
>
> Skylab landed on Western Australia
BZZZZZ, partial credit.
Skylab debris landed in an area stretching from the
south-eastern Indian Ocean to Western Australia.
It's amazing that ppl won't go to the trouble of looking-
it-up...
Check:
http://www.ksc.nasa.gov/history/skylab/skylab-operations.txt
- Bubbis >:-)
George Skinner
Thanks for the corrections, everyone. I should have re-checked
everything before I posted. It's been a few years since I read all of
those articles about Skylab, esp. the ones about the increased drag on
the station (atmospheric, _caused_ by increased solar activity). Skylab
_did_ hit parts of western Australia. I remember everyone getting
uptight about Skylab crashing down on their heads back in 1979 (Why
didn't the U.S. gov't fork up the money to boost it to a higher orbit,
then?), and I remember a serious-sounding announcer cutting in during
Sesame Street (I was 4 at the time) announcing "Skylab has crashed into
the Indian Ocean...". It sucks to have missed the really exciting part
of space exploration in the '60's and early '70's. Watching Columbia
blast off isn't much of a thrill now that its blasted off 70 times.
Doug Jones
George Skinner wrote:
[snip]
> the Indian Ocean...". It sucks to have missed the really exciting part
> of space exploration in the '60's and early '70's. Watching Columbia
> blast off isn't much of a thrill now that its blasted off 70 times.
Sorry to disappoint you even more, but the entire shuttle "fleet" (I
hesitate to call four vehicles a fleet) has not yet made 85 flights, so
Columbia has possibly made 20-25 flights.
I saw the NASA pavilion at Oshkosh the other day, and some nasa flack
was trumpeting X-33, saying in one breath, "It will fly in two years, be
operational in four."
I had the good grace not to laugh out loud at him.
--
Doug Jones ran...@eau.net
If they call it tourist season, why can't we shoot them?
Greg d. Moore
Doug Jones wrote:
>
> George Skinner wrote:
>
> [snip]
>
> > the Indian Ocean...". It sucks to have missed the really exciting part
> > of space exploration in the '60's and early '70's. Watching Columbia
> > blast off isn't much of a thrill now that its blasted off 70 times.
>
> Sorry to disappoint you even more, but the entire shuttle "fleet" (I
> hesitate to call four vehicles a fleet) has not yet made 85 flights, so
> Columbia has possibly made 20-25 flights.
>
I believe this launch was the 86th in the shuttle program.
> I saw the NASA pavilion at Oshkosh the other day, and some nasa flack
> was trumpeting X-33, saying in one breath, "It will fly in two years, be
> operational in four."
>
> I had the good grace not to laugh out loud at him.
>
No, but I would have pointed out that X-33 will never be operational.
VStar might, but not X-33.
> --
> Doug Jones ran...@eau.net
> If they call it tourist season, why can't we shoot them?
--
Greg D. Moore President moo...@greenms.com
Green Mountain Software http://www.greenms.com/
518-273-8602
Mike Dicenso
On Thu, 7 Aug 1997, Doug Jones wrote:
> George Skinner wrote:
>
> [snip]
>
> > the Indian Ocean...". It sucks to have missed the really exciting part
> > of space exploration in the '60's and early '70's. Watching Columbia
> > blast off isn't much of a thrill now that its blasted off 70 times.
>
> Sorry to disappoint you even more, but the entire shuttle "fleet" (I
> hesitate to call four vehicles a fleet) has not yet made 85 flights, so
> Columbia has possibly made 20-25 flights.
>
Close but not quite! The STS has just flown it's 86th mission as of
08/07/97. Columbia, and Discovery are now tied at 23 flights apiece.
-Mike
Mike Wilson
--
Mike Wilson | @ @ \/ \*/ \*/ \#/ Springtime
Draketown | | | | | | |
in the
Des Moines, Iowa | mwi...@ia-omni.com mind
http://www.ia-omni.com/mwilson/index.htm
Doug Jones <ran...@eau.net> wrote in article <33E9DB...@eau.net>...
> George Skinner wrote:
>
> [snip]
>
> > the Indian Ocean...". It sucks to have missed the really exciting part
> > of space exploration in the '60's and early '70's. Watching Columbia
> > blast off isn't much of a thrill now that its blasted off 70 times.
>
> Sorry to disappoint you even more, but the entire shuttle "fleet" (I
> hesitate to call four vehicles a fleet) has not yet made 85 flights, so
> Columbia has possibly made 20-25 flights.
>
> I saw the NASA pavilion at Oshkosh the other day, and some nasa flack
> was trumpeting X-33, saying in one breath, "It will fly in two years, be
> operational in four."
>
> I had the good grace not to laugh out loud at him.
Heh sounds like the same idiot that told my nephew last year that we would
be landing men on Mars by 2001.
Along that line, our space programs are so tangled up in politics and
"National Security" as well as funding battles, that it will take a private
consortium to really open up Space travel, mining and colonization. And it
will have to do it ignoring the UN Space Treaty
of 1968 which is very restrictive in this regard (to my recollection
anyway). Wonder if any of the mining companies have seriously considered
the "prospects"? The multinational Corporations are supra-national anyway,
maybe it's time they expanded outward into Space too.
SHedr24734
Let's not forget, that Skylab was not designed to be refueled or
restocked, it was launched with all of the maneuvering fuel and water that
it was ever going to have. So, even if it hadn't taken potshots at
aboriginies, it would eventually have to have been abandoned.
Tom Abbott
shedr...@aol.com (SHedr24734) wrote:
It has been a long time since I posted this. Apparently, too long.
Skylab's Untimely End by James E. Oberg, Air&Space, Feb/Mar 1992,
p. 73-79.b
"It was one of the more bizarre proposals offered in response to the
funding and design crises surrounding NASA's space station Freedom.
In June a shadowy organization calling itself the "Center for
Strategic Studies" suggested that instead of building Freedom, NASA
should take the backup Skylab on display in the National Air and Space
Museum in Washington and launch that. The disgruntled NASA employees
who suggested this idea did it anonymously..."b
"In the late 1970's NASA had considered saving Skylab by sending an
early space shuttle mission to boost it into a higher, more stable
orbit."
"Even more ambitious studies concluded that Skylab could have been
repaired, reopened, and expanded."
"It was a very serviceable, useful facility, " recalls Jack Lousma, an
astronaut who lived aboard it for two months. "It would have made a
good follow-on set of missions, a nucleus for expansion."
"As they left the station, they [the last astronaut crew to occupy it]
removed the inside locking pin from the airlock hatch--in effect,
putting out the welcome mat."
"In the end, it was the Sun that spelled doom for Skylab. The final
crew used their Apollo spacecraft to nudge Skylab high enough to keep
the station in orbit until sometime in 1983. But in the late 1970s
solar activity intensified, heating and expanding the upper atmosphere
enough to increase the drag on the space station. As Skylab's orbit
decayed and its life expectancy decreased, the shuttle program
encountered more and more delays. Early plans called for the reboost
mission to be undertaken on the sixth shuttle launch, but schedule
pressures pushed it as far ahead as the second mission. However,
STS-2 wasn't launched until November 12, 1981, more than two years
after Skylab's charred remains had dropped across western Australia
when the spacecraft fell on July 11, 1979."
"Many at NASA were glad to see the end of Skylab. It could well have
been a snare and a delusion," says Joe Loftus, Johnson Space Center's
advanced planning director."
Alan Bean disagrees: "I think we should have kept it up there. It
wouldn't have distracted from anything. Maybe it would have had the
opposite effect: we could have really demonstrated space station
operations."
"When plans to launch a second Skylab were scuttled in 1975, some
preliminary thought was given to reopening the first one."
John Yardley, NASA's associate administrator for manned spaceflight,
initiated a study to demonstrate what the shuttle could do on a Skylab
visit."
"Engineers at the Skylab project office in Huntsville and Skylab
contractors such as Martin Marietta were convinced the station would
be in surprisingly good shape. More than just a handy target for a
shuttle mission, Skylab was potentially a resource of great value."
"But the wear and tear was in fact one of Skylab's most attractive
traits. The information about effects of long-term space exposure
would be vital to the design and construction of a new, permanent
space station."
"The engineers also catalogued the Skylab systems expected to be
operable. These included refrigeration, oxygen/nitrogen distribution,
carbon dioxide control (which used a molecular sieve more advanced
than anything that has flown since), waste management, medical
monitoring, trash disposal, ventilation, and the hatches (space seals
were aboard). The thermal control system would require servicing with
cooling fluid. The power, communications, and data management systems
would need augmentation. "All other systems should require minor
flight activities for reactivation, " concluded the final report to
NASA headquarters."
"Of the 6,000 pounds of water launched in 1973, nearly 2,000 pounds
remained (about 180 man-days' worth). The water system had valves
within the workshop for eventual refilling."
"There was an estimated 1,700 pounds (420 man-days) of oxygen in the
tanks. Since the refill valves were near the airlock, it would be
fairly easy for astronauts to replenish the oxygen during a shuttle
visit."
"Although the solar cells were aging and good for only a few kilowatts
of electrical output, the power buses and batteries were in good shape
for reactivation."
"Nitrogen supplies for the thruster system were low. They could be
replenished, but that would require an astronaut with a manned
maneuvering unit to get to the feed valves."
"In late 1977 NASA headquarters completed a four-phase rescue plan.
Phase 4 would have been a five-year plan of growth, with the addition
of Spacelab modules and pallets and perhaps a construction platform
based upon the shuttle's external tank." [!!!]
"Equipment for the first three phases was estimated to cost about $60
million, not including launch costs or the power module, which were
funded from different budgets."
But NASA, fixated on the shuttle program, wasn't really interested."
"The enthusiasts were those who had worked on Skylab and were quite
proud of it, but it interfered with the more global vision of glory
shared by the later generation at NASA."
"But could Skylab really have been revived? Most likely, yes. When
it was turned on briefly by ground command in 1978, the station's
power, command and control, and attitude systems all functioned
adequately. Years later, when the Soviet Salyut 7 station died and
froze, it was revived from conditions far more extreme--and then
operated normally (see "The Rescue of Salyut 7," [Air&Space] Feb/Mar
1990)."
"Perhaps the most damning argument against Skylab was something any
real estate agent can appreciate: location. The high-inclination
orbit (tilted 50 degrees from the plane of the equator) was not
convenient for shuttle missions. To reach Skylab, a shuttle would
have to be launched more to the north than usual, sacrificing some of
the boost offered by Earth's eastward spin. That wasn't a major
penalty for expendable spacecraft and boosters (about 10 percent of
maximum payload weight), but because the shuttle carries its heavy
wings and engines back to Earth, the weight sacrifices would have to
come from the payload. (To avoid this unacceptable [!] loss, Freedom
is to be built in an easterly orbit from Florida, with an inclination
of 28 degrees.)"
TA
Dan Hartung
SHedr24734 <shedr...@aol.com> wrote in article
<19970814055...@ladder01.news.aol.com>...
> Let's not forget, that Skylab was not designed to be refueled or
> restocked, it was launched with all of the maneuvering fuel and water
that
> it was ever going to have. So, even if it hadn't taken potshots at
> aboriginies, it would eventually have to have been abandoned.
Now, now, now. That was just the first "Mission to Planet Earth."