BBC's Pegasus spaceship

Those of you who've seen the BBC's Space Odessey documentary will agree that
the Pegasus is a pretty good design for an interplanetary tour around the
solar system. The only thing that we didn't hear too much about was how they
would sustain themselves for 6 or more years. There's no way you could carry
that much food for a crew of 8 people.

http://www.bbc.co.uk/sn/tvradio/prog.../pegasus.shtml

"Henk Boonsma" wrote in message
news:1100796602.HkEBW89vOn7HBP3Skjfcsg@teranews...
Those of you who've seen the BBC's Space Odessey documentary will agree
that
the Pegasus is a pretty good design for an interplanetary tour around the
solar system. The only thing that we didn't hear too much about was how
they
would sustain themselves for 6 or more years. There's no way you could
carry
that much food for a crew of 8 people.

http://www.bbc.co.uk/sn/tvradio/prog.../pegasus.shtml


Actually, it could. The food needed for that length of time can't weigh
that much, especially if it's all freeze dried. The web site said the ship
weighed 400 tons. Out of that 400 tons, the site says it contains "57
tonnes of food and 80 tonnes of oxygen". You don't think 57 tons is enough
food to last 8 people 6 years? That's 3.25 kg per day (over 7 pounds).

Of course, this is all just a "paper" design, with little chance of it being
built in the near future.

Jeff
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Remove icky phrase from email address to get a valid address.

In article ,
Jeff Findley wrote:
Actually, it could. The food needed for that length of time can't weigh
that much, especially if it's all freeze dried. The web site said the ship
weighed 400 tons. Out of that 400 tons, the site says it contains "57
tonnes of food and 80 tonnes of oxygen". You don't think 57 tons is enough
food to last 8 people 6 years? That's 3.25 kg per day (over 7 pounds).

3.25kg/man-day (which is indeed what that number translates to) is loads.
The average human requirement is 0.62kg of freeze-dried food, plus a
smidgen for packaging, plus a couple of kg of water for rehydration and
preparation. And you'll have to recycle water anyway -- washing dishes,
people, and clothes just takes too much of it -- so it doesn't figure into
long-term supplies much.
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"Henk Boonsma" :

Those of you who've seen the BBC's Space Odessey documentary will agree
that
the Pegasus is a pretty good design for an interplanetary tour around the
solar system. The only thing that we didn't hear too much about was how
they
would sustain themselves for 6 or more years. There's no way you could
carry
that much food for a crew of 8 people.

http://www.bbc.co.uk/sn/tvradio/prog.../pegasus.shtml

Did you try to do the math before making that statement? Basicly a person
needs about 0.5 metric tons of food per year and about 1.0 tons of water for
a total of 1.5 tons of supplies per person per year. 6 * 8 * 1.5 = 72 tons
of supplies needed at max.

Take another look at your spaceship, it is already carrying landers that mass
35, 45, 15, 28 and 29 tons each! What would be the problem adding in the
food? And worse to your claim is water is highly reclaimable and is being
generated the entire trip by the crew. You probably don't need to ship more
than 1.0 tons of water per person period, and maybe noteven that much.

So you get 6 * 8 * 0.5 = 24 tons of food.
And you get 8 * 1.0 = 8 tons of water.
Total 32 tons of supplies plus equipment to recycle the water, which I expect
to mass far less than 40 tons!

Earl Colby Pottinger

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"Andi Kleen" wrote in message
...
"Jeff Findley" writes:

Actually, it could. The food needed for that length of time can't weigh
that much, especially if it's all freeze dried. The web site said the
ship
weighed 400 tons. Out of that 400 tons, the site says it contains "57
tonnes of food and 80 tonnes of oxygen". You don't think 57 tons is
enough
food to last 8 people 6 years? That's 3.25 kg per day (over 7 pounds).

Wouldn't it need much more water than that? I wonder how much is left for
the
propellant and the rest of the hardware.
Or perhaps they're planning to mine some ice comets during the journey.
But if they did that they could as well mine the Oxygen there using
the power from their fusion reactor.

This was "designed" for a BBC TV show, so there isn't much detail there,
other than the pretty pictures.

For a six year mission, you'd think that they would recycle H2O (from urine
and from humidity in the air of the ship). I thought that when food an O2
were metabolized, you got water as a byproduct. If this is so, then you'd
think that recycling of H2O ought to take care of water requirements. Given
the fusion reactor, you'd think they could also recycle H2O from solid
wastes as well, by baking off the water in a furnace.

Jeff
--
Remove icky phrase from email address to get a valid address.

57 tones of beef jerkey can last a long time.


"Henk Boonsma" wrote in message
news:1100796602.HkEBW89vOn7HBP3Skjfcsg@teranews...
Those of you who've seen the BBC's Space Odessey documentary will agree
that
the Pegasus is a pretty good design for an interplanetary tour around the
solar system. The only thing that we didn't hear too much about was how
they
would sustain themselves for 6 or more years. There's no way you could
carry
that much food for a crew of 8 people.

http://www.bbc.co.uk/sn/tvradio/prog.../pegasus.shtml





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Henk Boonsma wrote:

Those of you who've seen the BBC's Space Odessey documentary will agree that
the Pegasus is a pretty good design for an interplanetary tour around the
solar system. The only thing that we didn't hear too much about was how they
would sustain themselves for 6 or more years. There's no way you could carry
that much food for a crew of 8 people.

http://www.bbc.co.uk/sn/tvradio/prog.../pegasus.shtml


Ummm...

"The frisbee-shaped disc at the front of the ship is an aeroshield
constructed from steel, carbon fibre and beryllium. This protects the
crew from radiation during the mission."

Uhh....

"Henk Boonsma" writes:

Those of you who've seen the BBC's Space Odessey documentary will agree that
the Pegasus is a pretty good design for an interplanetary tour around the
solar system. The only thing that we didn't hear too much about was how they
would sustain themselves for 6 or more years. There's no way you could carry
that much food for a crew of 8 people.

The lifeboat rations I keep in my earthquake kit weigh 0.5 kilograms per
2400 kcal, which is a healthy day's food for a moderately active adult.
The shelf life is listed as five years under arbitrary conditions, so
probably at least six under controlled conditions.

So that's eight or nine tons for the 8 man/6 year mission, and it would
all fit in my bedroom closet.

Now, for a number of reasons you really don't want to be eating lifeboat
rations for six years. But dehydrated food shouldn't weigh more than
1.5 kg/day and preserved but fully hydrated food 3.5 kg per day, so
that's twenty-six to sixty-one tons.


http://www.bbc.co.uk/sn/tvradio/prog.../pegasus.shtml

Four hundred ton ship, with fifty-seven tons of food. Seems OK to me.


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"Earl Colby Pottinger" wrote in message
...
"Henk Boonsma" :

Those of you who've seen the BBC's Space Odessey documentary will agree
that
the Pegasus is a pretty good design for an interplanetary tour around
the
solar system. The only thing that we didn't hear too much about was how
they
would sustain themselves for 6 or more years. There's no way you could
carry
that much food for a crew of 8 people.

http://www.bbc.co.uk/sn/tvradio/prog.../pegasus.shtml

Did you try to do the math before making that statement? Basicly a person
needs about 0.5 metric tons of food per year and about 1.0 tons of water
for
a total of 1.5 tons of supplies per person per year. 6 * 8 * 1.5 = 72
tons
of supplies needed at max.

Take another look at your spaceship, it is already carrying landers that
mass
35, 45, 15, 28 and 29 tons each! What would be the problem adding in the
food? And worse to your claim is water is highly reclaimable and is being
generated the entire trip by the crew. You probably don't need to ship
more
than 1.0 tons of water per person period, and maybe noteven that much.

So you get 6 * 8 * 0.5 = 24 tons of food.
And you get 8 * 1.0 = 8 tons of water.
Total 32 tons of supplies plus equipment to recycle the water, which I
expect
to mass far less than 40 tons!

The ship itself weights in at 400 tons but that's including its own mass and
propellants. That doesn't necessarily leave a lot of room for consumables
and water. The pictures don't seem to show a lot of storage space aboard
either.

The thing I like about the ship is the spinning gondola. I've been
advocating for years that NASA should stop all research on trying to find a
'medicine' that alleviates the bone and muscle loss and instead focus on
artificial gravity using spinning wheels or gondolas. It would also remove
the need for a lot of other research, such as how to operate on someone in a
zero-g environment.

"Henk Boonsma" wrote:
The thing I like about the ship is the spinning gondola. I've been
advocating for years that NASA should stop all research on trying to
find a
'medicine' that alleviates the bone and muscle loss and instead focus
on
artificial gravity using spinning wheels or gondolas. It would also
remove
the need for a lot of other research, such as how to operate on
someone in a
zero-g environment.

How is technology equipped to support the mechanical connection of the
rotating centrifuge and 'stationary' main structure? The connection
must (I presume) include a ring-bearing large enough to enclose a
human-sized passageway between the sections (two, in fact, if the
habitable sections extend both sides of the connection point), the
connection must be made leak-proof and there ought to be a gyroscopic
counter-provision (thrusters being impractical for long periods) to
counteract both the effects of spinning wheel and any 'leak-back' of
rotational energy due to the inevitable friction...

I've always been wary about connections between spinning and
non-spinning components of space-habitats/vehicles (except perhaps such
as in the filmed 2001[1] where both the shuttle and Odyssey appear to
have internally-maintained centrifuges, presumably fully-contained
within a pressurised 'inner' skin...

[1] I forget the details in the book...