|tgoyette||Manned trip to Mars?||2012-12-03 08:27:34|
|tgoyette||Should we send humans to Mars in the near future? It would be really cool and given enough resources we could do it. Given that we as humans can improvise and work independently we should be able to get more science done in less time than the rovers. However, rovers have proven to be able to work for years. There is a suggestion out there of sending up scientists on a one-way trip. What is your view of when and how man should visit the red planet?||2012-12-03 08:27:50|
|micheledutcher||There are still questions to be answered as far as radiation danger to the crew over an multi-month trip in space..so I would have my reservations. Beyond that, I would only send a crew somewhere that there was water (like Mercury's dark side). I wouldn't put a base on the moon without water. It would be cruel to send a crew to any planet on a one-way basis. Even if someone thought they could last it out, they would be condemning themselves to life in prison without parole, basically. It's 30 years too early for such an effort to Mars. I could see Europa in a decade, however - if we could offer them a way back. Are you thinking of calling the settlement Australia? Wrath of Khan? Terraforming 1st would work, surely. ||2012-12-03 12:57:20|
|mark211||A planned one-way trip would be profoundly unethical and there would have to be a question mark over the psychological health over someone who actually volunteered for such a thing - I think you'd have to be either a risk taker to the point of recklessness or else be someone with unrealistic expectations of their own abilities to cope. Either type of person would potentially jeopardise the phenomenal costs of the mission during the journey, let alone the landing. While I think there are limits on the seafaring journeys of people like Polo, Columbus, Frobisher, Cook etc. I think there is more than an even chance that people will make it to Mars ... but (I reckon anyway) that the world will have to change almost beyond recognition before we'll have the means to not only it but make it worth doing. At the very least I think we'd have to establish a presence on the moon as a training, acclimatisation and setting off point before making it all the way on to the red planet. ||2012-12-03 13:19:39|
|mark211||Oops! That should have said "While I think there are limits [on the comparison of space missions to] seafaring journeys of people like Polo, Columbus, Frobisher, Cook etc."
|r.tornello||here's a way to cut the travel time down. It existed:
I met one of the scientists who worked on this some time ago. He's still pissed!
In a nuclear thermal rocket a working fluid, usually liquid hydrogen, is heated to a high temperature in a nuclear reactor, and then expands through a rocket nozzle to create thrust. In this kind of thermal rocket, the nuclear reactor's energy replaces the chemical energy of the propellant's reactive chemicals in a chemical rocket. Due to the higher energy density of the nuclear fuel compared to chemical fuels, about 107 times, the resulting propellant efficiency (effective exhaust velocity) of the engine is at least twice as good as chemical engines. The overall gross lift-off mass of a nuclear rocket is about half that of a chemical rocket, and hence when used as an upper stage it roughly doubles or triples the payload carried to orbit.
A nuclear engine was considered for some time as a replacement for the J-2 used on the S-II and S-IVB stages on the Saturn V and Saturn I rockets. Originally "drop-in" replacements were considered for higher performance, but a larger replacement for the S-IVB stage was later studied for missions to Mars and other high-load profiles, known as the S-N. Nuclear thermal space "tugs" were planned as part of the Space Transportation System to take payloads from a propellant depot in Low Earth Orbit to higher orbits, the Moon, and other planets. Robert Bussard proposed the Single-Stage-To-Orbit "Aspen" vehicle using a nuclear thermal rocket for propulsion and liquid hydrogen propellant for partial shielding against neutron back scattering in the lower atmosphere. The Soviet Union studied nuclear engines for their own moon rockets, notably upper stages of the N-1, although they never entered an extensive testing program like the one the U.S. conducted throughout the 1960s at the Nevada Test Site. Despite many successful firings, American nuclear rockets did not fly before the space race ended.
To date, no nuclear thermal rocket has flown, although the NERVA NRX/EST and NRX/XE were built and tested with flight design components. The highly successful U.S. Project Rover which ran from 1955 through 1972 accumulated over 17 hours of run time. The NERVA NRX/XE, judged by SNPO to be the last "technology development" reactor necessary before proceeding to flight prototypes, accumulated over 2 hours of run time, including 28 minutes at full power. The Russian nuclear thermal rocket RD-0410 was also claimed by the Soviets to have gone through a series of tests at the nuclear test site near Semipalatinsk.
The United States tested twenty different sizes and designs during Project Rover and NASA's NERVA program from 1959 through 1972 at the Nevada Test Site, designated Kiwi, Phoebus, NRX/EST, NRX/XE, Pewee, Pewee 2 and the Nuclear Furnace, with progressively higher power densities culminating in the Pewee (1970) and Pewee 2. Tests of the improved Pewee 2 design were cancelled in 1970 in favor of the lower-cost Nuclear Furnace (NF-1), and the U.S. nuclear rocket program officially ended in spring of 1973. Current (2010) 25,000 pound-thrust reference designs (NERVA-Derivative Rockets, or NDRs) are based on the Pewee, and have specific impulses of 925 seconds.
|Ironspider||No, let's keep our crap on one planet. We haven't earned the right to start screwing up a second one...||2012-12-03 23:23:20|
|mark211||Ha ha ha ; - )))
|micheledutcher||I certainly respect R Tornello's expertise in how to get to Mars, however the real trick is actually being able to set up a colony, basically. Sending two people there, for instance, would make them nuts in 6 months - unless there was another ship with more people coming ASAP. Humans are social animals. On top of that, humans must be somewhere with H20 available, either on the poles (Mars) or the dark side of the moon. ||2012-12-05 08:48:08|