magnemoe

Members
  • Content count

    6839
  • Joined

  • Last visited

Community Reputation

886 Excellent

2 Followers

About magnemoe

  • Rank
    Flight Director
  1. Note that you will have CNC machines and 3d printers as part of you initial infrastructure, presses for making plates too. However the list of things who is hard to make is far longer than the list you can make even with an advanced workshop on mars. You can 3d print the injector and use cnc for the nozzle but you can not make the turbo pump who require more advanced materials, you can probably not even make the ball bearings. However if you can also make the tanks and structure you can make more than 90% of the weight, the rest you import or recycle. Almost all ISRU for construction focus on the basic items who is easy to make and you need lots of, far easier to ship electronic than concrete. And an complete self independent colony is very far off as in hundred of years and even then probably require an political desire to make it independent even if very expensive.
  2. Yes, note that the hydrogen in an nuclear thermal engine is not much hotter than an h2+o2 engine, however as you only use H2 who moves faster than oxygen or water at same temperature the isp is far higher.
  3. Problem is getting an huge ship into orbit undetected. You can hide an small pod falling free, or at least show it off as an comet fragment, not an huge ship with powerful engines. Easiest solution would be to get smuggled in, pay some freighter captain to take you in, you could parashute out before landing to avoid border control you could even do an moose deorbit if going to space station first. Have captain say he dumped some barrel of stuff illegal in the system he found one client tried to get him to transport for the fun factor.
  4. Simplest would be to look harmless, for this you need to be pretty small, put an shield towards earth, this has ambient temprature or close to it, pod is behind. If noticed you look like an 2 meter comet fragment, so small it will break up in atmosphere and it will hit in the wilderness anyway. And you break up, on entering, you loose the forward shield if not pulled in and used as heat shield, you loose the living area and life support leaving just an drop pod, probably breaking this to, Now problem would be inserting the pod into the trajectory it would need an mothership. This you can not hide,
  5. Making highly enchanted uranium is hard. Not something you will do in space then its replacing engines every decade.
  6. Nice landing, smooth as you can do it. Was a bit scared after separation as speed fell and continue to fall, I expected an small drop before second engine spun up but it continued to fall then I understand it was first stage data.
  7. he spacex webcast is better, it doesn't have any chat so you don't have to listen to obvious trolls ranting all the time
  8. NTR has two major issues, its the cost of develop it and the lack of missions, like in KSP you need an manned mission or an huge probe mission (europa sample return) for it to make sense. For small probes the engine is to heavy. Political its probably more of an congress issue, you have an expensive program with limited use and some politicians would fear the critic from pressure groups, NTR are common and far more of an radiation issue on fail than an non started reactor. People protests against nuclear plants in their backyard not nuclear submarines. Am talking huge protest not some loons who also protest because the sun set. Neither China nor Russia has shown much interest and they don't have political problems with it. makes me wonder if an NTR upper stage would be practical for an manned Moon mission? Know the US looked into it but could not get NTR ready in time. We know China aim for this. Benefit would be single use short burn time with return to earth in a week if fail, the high ISP should reduce the fuel requirements for the upper stage who also do moon injection. The short burn time and then eject would reduce the need for shielding. Shield and engine weight would be an downside here. You can not use an long boom to get distance from reactor either.
  9. Changing the moderator staff positions could compensate for different fuel within some limits. An nuclear reactor don't burn out in reasonable time (years of use)
  10. Yes, if a bomb don't go off it would simply fall behind, one issue would be an fizzle, as its an shaped charge you might get an uneven blast given uneven pressure on plate who could damage the shock absorber. The shock absobers would be easy to calculate requirements for. This would be the first obvious question and must have been done for the smaller designs who got detail plans. Plates would be easier to build today because of better materials, And yes you would have to test it well.
  11. An 20 km pusher plate would be somewhat expensive. it would also make the ship huge an massive. An medusa like construction would be more practical at this sizes, as the parachute would be pretty thin,main issue would be how many blasts it could take.
  12. Starshot is based on the idea of reflecting laser light between two mirrors lots of times. This probably work, reaching 10% of c with an 50k g acceleration over time has some issues Using it to send small cubesat around in the solar system would make sense.
  13. An SR-71 at cruise speed moving just below 1 km/s has an very short window if one engine fails, if it run on one engine it become fragments very fast. This happened, pilot found himself in just the seat then he recovered, second crew member did not survive. In short losing aerodynamic stability at high supersonic speeds is very bad.
  14. yes, it was 2 or 3 km/s, you could stage at 1 km/s however this would be in atmosphere and also make upper stage larger. 2 km/s is more common. One issue with having upper stage in front is that you don't want takeoff wheels on the upper stage, it would need to be far more beefy than needed for landing an probably longer too.
  15. Main problem would be to contain the nozzle at the end. You use solid rockets for TWR, hydrogen for ISP, optimized liquid fuel has very low dry mass ratios. You want the SRB to be cheap and simple. Note that some interstellar designs think of using structure as reaction mass or even fuel.