Green Baron

And absolutely sterile. Even on earth the open ocean is a desert. Guys, it is all not that easy. Water is only the solvent. There will be no life in the narrow margin if there is no constant energy supply and all the elements (ake nutrients) needed are present in a reasonable distribution. Until positive notice we only have our speculations. From what i know of geoscience and palaeontology Europa is dead and cold place.

Floating point power may be thee limiting figure. That had to be emulated then, became widely used as late as the 80s. Today graphics are based on it.

"Habitable" in this context means "equilibrium temp. is can be between 0 and 100 degrees Celsius somewhere on the surface, without any atmospheric influence and according to our models for stars and their energy production". That leaves a lot of room for speculation and does in it self not take into account for any of the factor necessary for life(tm). But i think everybody is aware Edit: i just realized that the proposals for our suns "habitable" zone now range from 1 to 10 AU (!) and atmospheres are included; according to the heap of hot waste called Wikipedia. When i last looked Mars was just outside of it ... the whole concept "lives" with hopes and expectations :-)

Ok. Then take it to Europa/Ganimede/Enceladus and let it scare off the aliens there.

Confused (not that this was something special for me ). Nasa says EM-1 not before end of '19 and EM-2 mid '22, the unbiased industry source says first mission around '23, i won't speculate about the second flight then. I can only deduct that there there is nothing concrete to speculate about. If that makes any sense ...

An eltbot does not exist. "Philbert Probe", why not, maybe in 100 years, with a portable fusion reactor :-) Right now we do not even know what to look for and where. Want to risk a lucky shot worth 2 billions ? In 10 years when SLS is a thing ?

Yep, but these microbes have a history, they are a few years/months old and the environment is very different. You cannot deduct microbes over Europa from it. Probably not me thinks. I think the whole microbes-on-Europa thing is just a hype fed by a lack of hard data. From what i read the plumes might well have just geologic/surface causes and the underground ocean on Europa is questionable. An exact measurement of the deformation by tidal forces would help ... if Europa Clipper launches it could do such a thing. Juice is planned to such a thing on Ganymede.

Hehe, Kerbal typo :-) But an intra-surface landing (cryo-braking :)) might happen looking at the surface features from far away ... I don't object, any landing on a distant moon might be a bonanza. But that will not happen soon. There are probably just vapour vents caused by geologic movement and the friction of the crystalline ice sheets (study 2016). Very interesting from planetary science pov but the life watchers might be disappointed. Juice will soon(tm) be on its way, one year before SLS is rumoured to lift off for the first time :-) Hail the probe :-) Yes, and :-) ? Compared to Europa's surface the ISS exterior is a paradise, warm/hot, shielded, and in ongoing contact with earths rich lifeforms with a history of at least 3.7 billion years. This says, if that was your implication, very little about the presence of such things on Europa. Or have you put something there and that was the whistling ?

I can't :-) That alone would not rectify a billion funds mission. It is unlikely to find a microbe in a plume ... i'd rather play the lottery ;-) Edit: we'll have to wait for Europa Clipper and/or or Juice to address some of the questions.

We've been through this too often. To sum up: To find microbes on Europa you'd have to dig deep. Neither man or machine could do this even on earth if the ice is solid. The "ocean" is a hypothetical construct that fits well the observations, but has been questioned again lately when cracks in the surface were attributed to possible tidal effects only (paper is linked in the forum, i kindly ask to search). Local water pockets (e.g. in the south pole region) can be a thing. Europa could most probably not have microbes just a few centimeters under the surface because it is too cold. Chemical reactions need temperature, best used above 0°C and below 100°C. And it is bathed in ionizing radiation that could kill an organism in a matter of days (check this pls. !) If life at all, then near hypothetical thermal vents at the bottom of a hypothetical ocean/water pocket driven by hypothetically strong enough tidal forces to keep the interior favourable. Hypothetically out of reach for anything that we could build, even on earth. Just see what was done for boring 3270.2m down the Antarctic ice shield (Epica). I agree that actual microbes for proof would be needed to actually prove something. Acquiring those would be short of impossible, even for a SLS BFR ETC PP thing ... rocket ... whatever :-)

Well, at least SLS will not break the rule that a launch has - up to now - never been preponed (is that a meaningful English word ?)

Work never shows up when we have the time for it :-) Your employer accepts your overtime despite you having nothing to do ? Sounds German generous to me :-) Cat has parasites. I managed to stuff it in the cage. Drove to the veterinary. Closed until Friday. Yeah, banal, i know.

Space based solar power is far fetched, to say the least. The purpose of the SLS and Orion is pretty well described on the Nasa page. Should it come into being.

That brings me to the question, what kind of infrastructure is needed at the ground for an automated booster landing. I assume some sort of dgps and a "Hi i am here" beacon at least ? Or do we not know ?

And still >=2 years to go until the first SLS launch ... we should stop running in circles :-) The ICPS will not be human rated i read. What will replace it then, the EUS ? Is the ICPS a modified DCSS or is the DCSS a thing on its own ?

Eh ? Please stop claiming false things. Energy production is No.1 cause of global greenhouse gas production an thus directly adds to global warming, more than 25% of all reviewed sources. Another direct effect is, of course, waste heat, which can have grave local consequences. https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data And these guys are meanwhile on the "dark side". I could add to this: global warming is all about energy !

The guys that calculate that probably are aware i'd guess and weigh between the options. EM-2, that would mean 2022 as earliest date, if the evaluation and reality are in favour ...

I don't have dV time for this ... *waveshand* :-) Yeah, i wasn't that serious.

Spock would say, the number is infinite, and add a lecture in Vulcanian philosophy. Just sayin' :-)

Zubrin and his text on the "Mars Society" page fits completely in the conspiracy theme, seeing enemies where there are none and scoffing at the work of others without presenting a concrete solution. Ignore the guy, stick to science, in the long run you will be right ;-) If you willingly follow the likes of him you will sooner or later be disappointed. The "worst possible transfer" dV wise would be at a phase angle between the planets where you had to completely cancel out the orbital speeds, like Mars behind Earth. The "worst possible transfer" time wise could be several years long (Earth or Mars, totally banana), depends on how many times you want to orbit the Sun until you finally get too close to Mars. There is, i'd think, no practical time limit ... (must be checked whether that is true). The fastest possible transfer would be the Brachistochrone, where you'd accelerate ~50% of the time towards and the other ~50% backwards. That'll be amost a straight line (try it out in the open source game "Pioneer"). With chemical propulsion that is, of course, impractical, if i may say so :-) I think (but i am not sure), that 8.5 months(*) is the Hohmann transfer that raises the AP from Earth just to Mars orbit at a time when the phase angle between the planets is near optimum (every +/-2 years or so, writing this without a check.). You'll arrive at Mars with a v-inf that reflects the orbital differences between Earth and Mars - Hohmann - Oberth(**). If the ship has more dV than are necessary for this classical Hohmann maneouver than it can shorten the trip, as said above, by accelerating longer, thus raising the AP above Mars orbit, but then it'll have to perform a mor radical braking maneouver there. KSP standard :-) (*) edit: yes, it is :-) (**) speak Obert, not Oberth

Nice shot. Has nobody realized the reflection of the photographer in the camera lens ? The fine dust that is seen all over the cart isn't exactly mechanics- and maybe one day health friendly, i read.

But - if the DSG is done one future day - it would be the first data obtained in a controlled way. That could mean a step forward out of the current insecurity. Nasa says that even during a quiet journey in a craft shielded better than the Apollos the crew will take a too high radiation dose. "Anecdotal" data is data as well :-) But well, assuming the first launch of the SLS takes place at the end of 2019, we won't see a DSG around the moon before the mid or late 2020s ...

True. I actually asked myself why didn't i find it last time we had this discussion ... maybe a slight change in search term spelling ... :-)

"Hey guys ! We've halved your rations ! If you want to quit, any time, take the dinghy. We'll pick you up when we have the time !" A what ? And there is a ground crew on Mars that helps the poor guys and gals out of the can, gives them a glass of champagne (one for all because budget), there is medical supply and Bones waits just around corner ("He's dead, Jim !"). I am sorry and must apologize for being sarcastic, just this morning i criticized a colleague for playing his jokes on me. Sorry @kerbiloid ! Edit: the grafic you linked, @DAL59, is most likely a fraud, the sources i ckecked tell a different story. Example: https://www.nasa.gov/home/hqnews/2013/may/HQ_13-165_MSL_Radiation_Findings.html tldr: Survivable. I mean, exactly that, survivable. Just not by everybody. Edit: https://www.aaas.org/news/science-mars-mission-reveals-radiation-risk-future-astronauts

Only a few days. No ITS because no ITS because no ITS. No. You didn't even take a look at what i linked, is that true :-) ? So here's more food for the brain. I am glad that people at Nasa are aware. https://srag.jsc.nasa.gov/Publications/TM104782/techmemo.htm https://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays and https://www.nature.com/articles/srep29901#t1 The authors if the last one admit that the sample is too small. But these are the only ones. We do. It costs 100s of billions in the developed countries because people get sick. Now THAT one is shooting soldiers ;-)