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Number04

Member

From: Calgary Alberta Canada

Registered: 2002-09-24

Posts: 162

Re: Payloads - Sending them before a manned mission?

Would it be possible, or is there even a point, to send any non essential payload for manned missions before they get there? Instead of sending allot of building materials and raw steel (or whatever) are there any plans to send that stuff on it's own to lighten the load for the manned mission?

Phobos

Member

Registered: 2002-01-02

Posts: 1,103

Re: Payloads - Sending them before a manned mission?

If they plan to send extra habs to the surface of Mars as a redundancy measure in the case of emergency, I think it could be a good idea to stock the spare hab full of things that might not be necessary but could help make life more bearable for the people who land there.  You could just replace the mass of the people that would normally be there with other things.

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To achieve the impossible you must attempt the absurd

RobS

Banned

From: South Bend, IN

Registered: 2002-01-15

Posts: 1,701

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Re: Payloads - Sending them before a manned mission?

Mars Direct envisions only two vehicles being sent to Mars: the hab and the ERV. The latter is designed to carry about ten tonnes of cargo right now, but it's a reactor on a truck and six tonnes of liquid hydrogen. If those are no longer needed, it could carry other items. Other plans for Mars exploration postulates cargo landings. The big problem with automated cargo landings, though, is making sure everything comes down in the same place. You wouldn't want the crew and two cargo landers in one place and the inflatable hab in another; or the three landers in one place and the crew in another. In Mars-24 I sort of solved the problem by sending two sets of everything; three cargo landings and one set of crew each opposition, with three cargo landers and the extra crew return vehicle going first. That way if one of the cargo landers crashed during the first (unmanned) expedition, you could send an extra the next time (in addition to the three automated landers already scheduled) and if the crew landed in the wrong place there would be three automated cargo landers following with everything they needed. Still, you wouldn't want the lander with their inflatable hab to crash; they'd have to live in the shuttle's cramped quarters, plus the pressurized rover, plus the greenhouse for eighteen months!

           -- RobS

Ranger_2833

Banned

From: My secret bunker in Wyoming (o

Registered: 2002-09-12

Posts: 55

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Re: Payloads - Sending them before a manned mission?

Considering just the launch aspect of the mission, it depends on how much mass you plan to launch and what launch systems you have availiable. 
   If there is a vehicle capable of launching the entire payload then it is usually cheaper to launch as one payload (the space shuttle is a major exception, but I won't go into that subject right now ??? ).  Multiple rockets would use more fuel because instead of having one large vehicle's support structure and guidance systems, etc. added to the total payload mass, you have multiple support structures, etc. to add into the overall mass (the extra mass of the larger rocket is almost always less than the combined extra masses of the multiple rocket system).
   On the other hand, if there is no vehicle capable to launch the total payload (the Proton rocket, one of the largest, is only capable of putting 19,760 kg into Low Earth Orbit at a cost of around $50 million), it is cheaper to use multiple launch vehicles than to design one for this purpose (unless of cousre you are looking at the long time prospects and plan to use this new rocket for other applications than this mission, but lets assume this mission will be unique for the near future).
   A third option is also availiable.  Hybrid designs using easily designed componets on existing hardware can be a very economical choice, but it depends on exactly what the hybrid consists of.  A good example is the Heavy Lift Launch Vehicle (HLLV), which was basically a rocket with the payload put in place of the shuttle on the external fuel tank and solid boosters.  It would have been capable of launching around 70,00kg into a Lunar or Martian trajectory!  But it never got of the drawing board, and here we are 33 years after Apollo 11 still stuck in Low Earth orbit.

   I hope I didn't babble too much and I answered your question. 

Nuclear Propulsion:  The faster cheaper way to Mars!

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Just another American pissed off with the morons in charge...

Motto:  Ex logicus, intellegentia... Ex intellegentia, veritas.