sgt_flyer

Kourou launches for Arianespace commercial customers is less stuffy generally - for most commercial launches (most of the streams ;)) and even 'repeat' missions like iss launches, there's much less to explain when it's a one shot science mission, even nasa streams are a bit more stuffy now, there's also the opposite end of the spectrum with waay too much, with spaceX personnel cheering for every single phase of the launch, while other companies only cheer on mission success

mmh, Proton fueling started at 3:31 GMT, was completed at 6:30 GMT. greenlighted for launch at 3:50 GMT, with weather prediction ok. http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_launch_updates meteo update at T-1h10 (taken from 3PM and 4PM LT): http://www.accuweather.com/en/kz/baikonur/225174/hourly-weather-forecast/225174 cloudy, around 50% humidity, temperature 3⁰C, chances of rain between 22% an 43%, 17% for snow, wind groundspeed 7 km/h W edit : livestream up. http://www.esa.int/Our_Activities/Space_Science/ExoMars/Watch_ExoMars_launch

beware though - this one is a classic single burn srb only

DSSP have various contracts with nasa, darpa, army, airforce and navy - they plan to go from propellants, gas generators, electric primers, even variable yeld explosives derived from their rocket fuel. http://dsspropulsion.com/space-defense/development-programs/ - found something on some of their planned engines : http://dsspropulsion.com/wp-content/uploads/2015/01/DSSP-Cube-Quest-Poster.pdf (beware though, it seems the CDM-1 engine is just a classic SRB ;))

heh they would need extra radiator arrays to keep the thing cooled down instead of solar panels

@PB666 we should look at costs maybe ? just a PPT unit (much less efficient than busek's rf ion thrusters) for cubesats cost nearly 20000$ - not counting the price of the solar arrays !. (basic cubesat kits can be found for 8000$) http://www.clyde-space.com/cubesat_shop/propulsion/303_cubesat-pulse-plasma-thruster http://www.pumpkininc.com/content/doc/forms/pricelist.pdf

err C-4 explosion is triggered by both heat and shockwave at the same time - you basicaly need a detonator to trigger C-4 explosion . this electric solid propellant simply start to combust when electric current pass through it - and the combustion stops when you stop applying current to the stuff (and if there's still fuel left, it can still reignite afterwards when you reapply current) . at this point, it's just a matter of getting the resulting gases from the combustion through a nozzle

better choices ? err... with this kind of ISP and thrust ?? there's not a lot. especially if you have to account for your pressurising gas,solenoid valves, heaters and all the plumbing... (costly to make all that plumbing) limiting satellite costs and improving their reliability is not vain here's the kind of isp you could get with the power avaible with currently avaible cubesat solar arrays on resistojets ... (50w to 70w...) http://www.sstl.co.uk/Products/Subsystems/Propulsion-Systems/Low-Power-Resistojet#fragment-3 isp 99s with nitrogen with 50w, and 100mN thrust. colloid microthrusters, like those on Lisa pathfinder, should be better, but i was not able to find much about their performances.

safe handling, utter simplicity (no moving parts) for RCS control (granted, more suited for cheap small satellites) - as the propellant extinguish itself when the electric current is removed (and can reignite afterwards if you reapply current). - given the size of the ESP microthrusters, it could even be used on nanosatellites for which it would be utterly impractical to put even a liquid monopropellant RCS system.

@PB666 the paper linked by Shynung is about Digital Solid State Propulsion technology (the one used for Spinsat) - they formulated a solid material that stays ignited only while applying constant electric power (ISPs cited between 220s and 280s. basically a safe controllable SRB fuel - as it doesn't ignite under flames or sparks) edit : here's spinsat aboard ISS, before it was released from iss. given the size of the thing, i doubt power requirements are on the same order as those needed for vaporising metals

here's the link for ESA's upcoming livestream for Exomars launch. http://www.esa.int/Our_Activities/Space_Science/ExoMars/Watch_ExoMars_launch The livestream will begin at 8:30AM GMT on monday march 14th. 2:30PM Local Time (at baikonur) 4:30AM EST, 12:30AM PST, 9:30AM CET) the launch is currently planned at 9:31AM GMT on march 14th. 3:31PM Local Time, 5:31AM EST, 1:31AM PST, 10:31AM CET current weather predictions for march 14th at baikonour for the launch: http://www.accuweather.com/en/kz/baikonur/225174/hourly-weather-forecast/225174?hour=33 at 3PM(LT) : mostly cloudy, 4⁰C, 48% humidity, 0% chance of precipitation, surface winds 15km/h SW. at 4PM(LT) : mostly cloudy, 4⁰C, 42% humidity, 0% chance of precipitation, surface winds 13km/h WSW.

@YNM gyros in real life aren't like in ksp they don't give you unlimited rotation capability (once they are saturated you need to respin them creating countertorque in the spacecraft ) (also, they take space & dry mass too ;)) still, the figures they give still states low ISPs, between 220s and 260s. - depending on the fuel density, (which might be a bit lower than classic SRBs), it's not necessary a good thing for longevity. (something really sought after in large commsats)for cubesats and smaller small satellites though, it could give them low cost propulsion capability where the alternatives where either pricy or even inexistent, giving a lot more interest in low cost smallsats. though, there's adversaries coming up in hypergolic liquid propellants too. LMP-103s and AF-M315E for storable monopropellants - those have better ISP than hydrazine, better density, and much lower toxicity (they don't need heavy protective gear for fueling, and can transport the stuff by plane - that low toxicity alone would already reduce satellite preparation costs by a lot - personnel safeties cost a lot of time and money). http://enu.kz/repository/2009/AIAA-2009-4878.pdf https://www.rocket.com/files/aerojet/documents/Capabilities/PDFs/GPIM%20AF-M315E%20Propulsion%20System.pdf

actually, there's two other spacecrafts that used / use drop tanks the first one (wayyy before briz-M) was the ye-8 spacecraft / lander from the lunokhod program. it used side mounted drop tanks, which were used for circularisation around the moon. they were dropped before the final moon landing. the other is the Fregat-SB (which has flown a few times already, atop Zenit) - the ill-fated Phobos-grunt notably used this stage. (at around the 2mn on the video) still, as was said, that would make a hell of a lot of propellant to move on a drop tank the size of a second stage - as the superdracos are pressure fed, you'd need additionnal pressurising gas along with a pumping system, which would add on the dry mass.

mmh. i wonder how it'll work with the pressure fed superdracos. you'd need to include some sort of pumping system, (maybe use a pressurised bladder if you want to keep it mechanically simple), to counteract the spacecraft acceleration, as the propellants would have to travel 'upwards' several meters (especially if you pump from the bottom of your drop tank, as under acceleration, the fuel will want to stay at the bottom of the tanks) - that still would be a hell of a lot of propellant to move for a pressure fed system

depends if it can keep it's properties once melted, or if it decomposes into it's constituants. mmh, from a paper about those, seems that without active cooling, they expect duty cycles <20% - so guess heat management may be an issue http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1887&context=smallsat

guess it'll also depend on the costs of the fuel itself, once it reaches high enough production to see economy of scale. but it might be interesting to use it for at least the upper stage of an all solid rocket - with it's multiple firing capabilities and ability to stop it, along with the fact it's storable - simple, reliable & effective upper stage capable of high precision

guess it needs much less electric power to run than resistojets / arcjets (2kw of power for a 0.25N arcjet - the solar panels needed for that are really going to be expensive,between costs, size and dry mass - some cubesats solar arrays i've checked give out 56W...) besides, resistojets /arcjets still needs liquid reaction mass - so you still need a pressurising gas to feed your reaction mass to the engines, (and all solenoid valves etc) - ESP really have the potential to minimize devellopment and production costs on very small sats.

Spinsat has been deployed from ISS in 2014 to test out this technology (it was sent up inside CRS-4) http://www.nasa.gov/mission_pages/station/research/experiments/1019.html here's the website of the company who made those used on Spinsat http://dsspropulsion.com/technology/works/ here's a video advantages : safe to handle (solid, and only continuous voltage can work, the propellant does not really react to sparks, heat & flames (unlike classic SRB fuel) and can't make more simple mechanically (ideal for very small sats, to give them RCS capabilities) - density should be correct. (although you need the additionnal dry weight of the casing/nozzle & electrodes) its storable for a long time, and no need to have a pressurizing gas. i never found any infos on the ISP though. one small problem if you use one set of those thrusters more than the others on the sat, once the set empty you partially lose your rcs capabilities before you exhausted all the fuel.

@fredinno @Kartoffelkuchen i think he meant what took the video where we see the 1st stage landing from afar. not sure if it was a drone though. could have been a plane or an helicopter with a stabilised camera (and could also have been from Nasa instead of SpaceX, given CRS-6 was for Nasa). even if SpaceX has such a drone, it wouldn't be really meaningful to use it at night (go and try to land a drone at night if the barge's floodlights are out of order (because of vibration or impact) - the support ships would likely be a bit too far for reaching such a drone before it runs out of power (and if the support ships are beyond the horizon, it would be even worse to try and remotely pilot this drone :p)

@fredinno Oh i know it's just that the op said 'john glenn excluded' - besides, john glenn was way younger when he was selected the first time to become an astronaut

problem with EOR is that you'll have to either : use storable propellants (less isp, so you'd need much more fuel) in the transfer stage (but you can fly it in advance and check everything out before sending the rest), or if you go with a cryogenic transfer stage, fly up at least the crew just back to back with the transfer stage, to limit boiloff. (or the 'refueling vehicle' if you launched the transfer stage empty), mobilising an enormous amount of manpower to prepare and conduct both launches in the same timeframe. - EOR is really way more complex to pull off also, keep in mind that computer technology was really minimal at the time in 1963, more than 60% of the US integrated circuit production were for the apollo guidance computers (the AGCs) - just for computers of 64kbits of rom and 4kbits of ram running at 1Mhz - if you used more classic computers of that time for the EOR, it would have noticably increased the dry mass

if you want to know age restriction on selection, nasa does not discriminate candidates based on age at selection (as long as you're fit enough) (the past range was between 26 and 46). http://astronauts.nasa.gov/content/faq.htm esa has a preffered age range from 27 to 37 - again, fitness suitable for the age is something they look for. http://www.esa.int/esapub/br/br271/br271.pdf Rocosmos has a set of criterias though (including having russian citizenship, age under 33 ;)) - though less restrictive now than before, Rocosmos still looks for a specific height & weight range (Soyuz is really cramped ;)) http://www.astronautforhire.com/2012/10/cosmonaut-selection-criteria.html for people already selected while they where younger, seems there's no set time limit outside of physical fitness Peggy whitson will be on expedition 50/51 on iss at age 56. - but she already went to space before. (she was selected when she was 36) edit : found https://en.wikipedia.org/wiki/Jake_Garn - 52 at age of selection (born in 1932, selected in 1984 flew once on sts-51D) - though, there was a lot of political leverage to get him selected ;))

oldest still alive, per nationality (up to 1945) : soviet cosmonaut : https://en.wikipedia.org/wiki/Vladimir_Shatalov - born in 1927 US, after john glenn (1921) - nearly a tie : https://en.wikipedia.org/wiki/Frank_Borman born in 1928 https://en.wikipedia.org/wiki/James_Lovell, in 1928 - 11 days younger than Frank Borman german (with soviets): https://en.wikipedia.org/wiki/Sigmund_J%C3%A4hn, 1937 french : https://en.wikipedia.org/wiki/Jean-Loup_Chr%C3%A9tien, 1938 bulgarian : https://en.wikipedia.org/wiki/Georgi_Ivanov, 1940 belgian : https://en.wikipedia.org/wiki/Dirk_Frimout, 1941 japanese : https://en.wikipedia.org/wiki/Toyohiro_Akiyama, 1942 cuban : https://en.wikipedia.org/wiki/Arnaldo_Tamayo_M%C3%A9ndez, 1942 swiss : https://en.wikipedia.org/wiki/Claude_Nicollier, 1944 canadian : https://en.wikipedia.org/wiki/Roberta_Bondar, 1945

another problem with a fully spinning ship, is that you need a way to keep your antennas targeted towards earth, and keep your solar panels and radiators correctly orientated for sunlight (so you end up needing mechanical systems anyway to keep those systems correctly lined up, with the same problems as previously - torque, friction and reliability) fuel centrifugation and slosh would have to be taken into account too, maybe needing to be able to design the propellant tanks to be able to work both in zero-G and while spinning.

i don't know if is for spaceX - maybe they are just cautious (after all, while the lox would have evaporated, there might be some RP-1 leftovers that did not burn during the crash - or the barge fuel tanks (for the stationkeeping engines) could have received some damage.) still, guess it would be required if they intend to wash the deck - there's more than likely hydrocarbons residues on the barge's deck maybe if we can find similar barge images from previous attempts for comparison