LRO development |
LRO development |
May 2 2005, 01:31 AM
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#1
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Senior Member Group: Moderator Posts: 2262 Joined: 9-February 04 From: Melbourne - Oz Member No.: 16 |
Just read this interesting article about LRO
http://science.nasa.gov/headlines/y2005/28apr_lro.htm QUOTE "This is the first in a string of missions," says Gordon Chin, project scientist for LRO at NASA's Goddard Space Flight Center. "More robots will follow, about one per year, leading up to manned flight" no later than 2020." One per Year? Is this just wishful thinking or have any tentitve plans been mentioned for follow up missions after LRO? If the next one is going to be 2009/10 then I guess some desisions about it will have to be made fairly soon. James -------------------- |
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Guest_Analyst_* |
May 12 2006, 06:19 AM
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#2
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Guests |
Back to LRO. I never understood the "problem" caused by the Delta II spinning third stage. Many spacecraft with lots of liquid propellant (Near, MGS, MCO, Odyssey, Messenger) launched with this stage with no problem. And the delta V to enter lunar orbit is about the same (1,000 m/s) than entering orbit arround Mars.
I guess the switch to EELV has been because of mass issues and/or political reasons (away from Delta II, more EELV launches). Analyst |
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May 12 2006, 12:20 PM
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#3
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Member Group: Members Posts: 321 Joined: 6-April 06 From: Cape Canaveral Member No.: 734 |
I guess the switch to EELV has been because of mass issues and/or political reasons (away from Delta II, more EELV launches). Analyst The Delta II is already "bought". Now another user has to be found. No conspirancy here, NASA would rather keep missions on Delta II because it causes an artificial cost cap for the mission Thanks, sounds valid. On the other hand, Messenger does have a lot more delta V than 1,000 m/s, so a monoprop system using Messenger's tanks should give at least 1,000 m/s. They had trouble developing these tanks, but it has been done. This brings me to another question: Why do never spacecraft (MRO, LRO) use monoprop systems? Biprop systems are working (see my post above) and are well understood and much more efficient. Is the reduced risk and complexity really worth the cost of a bigger launcher (Delta II vs. EELV) and/or less payload? Analyst The trades actually were in favor of monoprop for MRO. Other than MOI, a biprop, would not be needed. The benefits of simplification of the prop system and elimination of dual hardware was greater than the inefficienies of a monoprop. |
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