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Author Topic: Can the Shuttle reach the Moon?  (Read 32426 times)
Pocci
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« Reply #30 on: April 19, 2011, 01:09:07 PM »

And if we reach the Moon we can return without fuel (see Apollo 13 or Cassini).
OK, after returning we want to reenter, that means to use some fuel again for braking, probably less than for accelerating because we are lighter now.

If it needs several accelerating orbits, it will need several breaking orbits and almost the same time as well.

/Armin
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Moonwalker
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« Reply #31 on: April 19, 2011, 01:37:49 PM »

Apollo 13 did not return home without fuel. If the descent engine of the lunar module did not fire for the PC+2 burn, Apollo 13 would have ended up in deep space after a lunar flyby. In order to return home, 3 burns had to be performed all in all if I remember correctly. And these spacecraft had rather powerful engines Wink
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Pocci
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« Reply #32 on: April 19, 2011, 02:26:05 PM »

As far as I know were all Apollo missions planned with a post-TLI-trajectory that in case of an engine faliure they would end near earth after passing the moon.
(Like Cassini passing Saturn and Titan on each orbit.)

/Armin
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Moonwalker
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« Reply #33 on: April 19, 2011, 04:30:00 PM »

As far as I know were all Apollo missions planned with a post-TLI-trajectory that in case of an engine faliure they would end near earth after passing the moon.
(Like Cassini passing Saturn and Titan on each orbit.)

/Armin

Apollo 12 to 17 left the free return trajectory after system checks and midcourse correction to aim for the landing sites. That's why the first burn after the Apollo 13 accident was required to return to a free return trajectory.

http://history.nasa.gov/afj/launchwindow/figs/Fig%205.png

But there is another issue: how do you decelerate the Shuttle without fuel once it gets back to earth? Grin Remember: it's 3g maximum and if the thermal protection system would survive an entry with about 25000 mph is unknown.

I doubt it is a good idea to fly to the Moon with no fuel left in any case. For sure it doesn't work for a proper return with a Shuttle due to its limitations.
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Cthulhus
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« Reply #34 on: April 20, 2011, 07:11:14 AM »

What kind of modification we need to allow the Shuttle to go to the moon ? We can imagine a LEM on the Payload Bay and with extra OMS tank fuel too for the trip Smiley

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« Reply #35 on: April 20, 2011, 09:19:39 AM »

What kind of modification we need to allow the Shuttle to go to the moon ? We can imagine a LEM on the Payload Bay and with extra OMS tank fuel too for the trip Smiley



The only modification we need is LOTS OF MONEY! Smiley

/Admin
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Cthulhus
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« Reply #36 on: April 20, 2011, 09:38:22 AM »

More than the Constellation program ?
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« Reply #37 on: April 20, 2011, 01:00:18 PM »

More than the Constellation program ?

No, of course not, but if we were to chose, my vote would go for a new, manned Space Exploration program (Moonbase, Mars) instead of modifying STS for pointless Moon voyages.

LEO transportation, taxi jobs, can be handled by private companies in the future, after they pass safety rules. NASA already set aside +$275M for this purpose, and shared this budget among its commercial partners, SpaceX among them. They have to be "human flight worthy" by 2013, otherwise they lose their funding.

What's funny is that Jeff Bezos (Amazon) also got a share of the budget. Next we'll have a "Kindle In Space" program - LOL!

/Admin
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Cthulhus
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« Reply #38 on: April 20, 2011, 01:07:28 PM »

Thanks Admin for details Smiley
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Cras
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« Reply #39 on: April 20, 2011, 05:30:40 PM »

Check out the book "Back to the Moon" by Homer H Hickham.  Its about taking the shuttle to the moon and back.  It is very factual since Hickham worked at NASA for so long, but also quite the fictional story.  It is dated, and for reasons I will not tell in hope of not spoiling the story for anyone, but it is quite entertaining.
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Cthulhus
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« Reply #40 on: April 20, 2011, 06:11:11 PM »

Yes, thanks, I'll read it ! I just finished Titan from Stephen Baxter...

Ok, they go on Titan (A moon of Saturn) with Discovery ! Amazing Smiley So why not the Moon ? Grin
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Cras
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« Reply #41 on: April 20, 2011, 06:17:35 PM »

Its a fun book, you should enjoy it.

And I will certainly pick up "Titan".
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« Reply #42 on: April 20, 2011, 09:20:36 PM »

HH is cool.

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thammond
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« Reply #43 on: April 20, 2011, 10:18:44 PM »

I believe that the early Russian moon probes used direct insertion trajectories while I think all the US moon probes (at least the early ones) and apollo used an initial parking orbit.  So I always wondered why the difference and if one way is more energy efficient than the other, which would be relavent to this discussion?  Does anyone know?

How about for the return to save on fuel utilize aerobraking.  Drop down into the atmosphere low enough to bleed off some energy, but not deep enough for reentry.  Then go back out into orbit.  Could do that multiple times if necessary, although the extra time to perform this would require additional life support.
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Moonwalker
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« Reply #44 on: May 01, 2011, 04:54:36 AM »

What kind of modification we need to allow the Shuttle to go to the moon ? We can imagine a LEM on the Payload Bay and with extra OMS tank fuel too for the trip Smiley

Here you go for the NASA analysis, but it is not based on any OMS usage but SSME usage (the OMS simply is not powerful enough and the payload bay would not offer any space for additionals payloads other than fuel anyway):

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19910014907_1991014907.pdf
« Last Edit: May 01, 2011, 05:04:00 AM by Moonwalker » Logged
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