Rakaydos

You'll physically spaghettify before you run into temporal gradient issues.

Rocket engines are designed to be the most efficent way of turning weight (fuel) into velocity change. SpaceX simply noted that at this point, they're good enough that a parachute would weigh more than the fuel to run the engine a little longer.

Not by much... it really looks like the vertical velocity almost zero'd out just, it's the horizontal velocity they couldnt manage.

http://www.planetaryresources.com/

It's a matter of priorities. A corporation wants to make money, so it pays attention to money. A goverment wants to stay in power, so it pays attention to power blocks and things like in-state jobs. Not saying one cannot be just as good as the other... but they usually arnt. and the Shuttle -definately- wasnt.

The shuttle was "reusable" in the same way a politician is "honest." The SRBs only reused scrap metal, at cost, just to maintain the claim that the "entire rocket is reusable." Like the so called "Senate Launch System" that is supposed to replace it, the shuttle was designed to fill political objectives, not scientific ones- And jobs refurbishing the shuttle were more politically valuable than not needing refurbishment in the first place, like if they'd stuck to the titanium heat shield instead of the foam glass tiles. SpaceX, on the other hand, is a corporation, not a goverment. Far from trying to create taxpaying jobs, a corporation is biased toward providing the most marketable service/product for the least overhead, and keeping all the money for itself. This means SpaceX has far more reason to have EFFECTIVE reusability than the US goverment ever did. The Falcon and the Space Shuttle simply arnt comparable in that regard.

Actually, someone is crazy enough. Unfortunately, their first survey probe was hitchhiking on the Orbital Sciences rocket that exploded.

Wait, are you running these numbers assuming a round trip to the asteroid belt? Because all the asteroid-mining proposals I've seen rely on Earth-crossing asteroids like the ones coded into KSP.

Again, this thread is going afield. It is supposed to focus entirely on SPACE INFRASTRUCTURE of the future, with our CURRENT understanding of physics. 10 Venus Cyclers and 14 Mars cyclers as large space stations with permanant populations to support the transient populations... feasable?

What does machine inteligence have to do with infrastructure? even a hyperinteligent AI cannot change the laws of physics.

The overriding premice of the OP is that 1) no new fundamental physics, so nothing like Warp or Gravity manipulation tht would change spaceflight as we know it, and 2) Enough lead time to take existing physics to the logical extreme. (well, almost to the logical extreme- as I said in the OP, I'm putting my foot down on long carbon nanotubes) This is also meant to be an index for space infrastructure concepts like large "Space Colony" cycler stations.

Without assuming new fundamental physics, there's been a lot of ideas floated as to make access to space, and access through space, cheaper and easier. I'm looking to compile a big list of TRL 4+ concepts. (so, no warp drive or wormholes. If an idea needs Multi-KM long carbon nanotubes, or a similar level of technological development, I'm assuming it isnt -completed- in the dawn of the 31 century and therefore not listed. if you disagree with my timeline, feel free to replace "31st Century" with "23rd century" or "40th century", whatever you believe fits) Earth Launch: Saber/Scramjet SSTO- Combining the dual-mode Jet/rocket Saber engine and the Scramjet high velocity air breathing engine to achieve the minimum fuel fraction to reach orbit in a reasonable amount of time, with direct reusability without staging (and thus stage recovery). Not being location specific, it will probably fill the suborbitl passsanger and light cargo market, but it's air breathing mass overhead makes it limited to earth orbit applications, with perhaps lunar L1 tether rendevous capability. Airship to Orbit (ATO)- a launch architecture that uses lighter than air designs to eliminate any concern for gravity losses. The firststage is either an airship on a balloon- lifted tether that brings the cargo above 95% of the atmosphere, to the point where turbulence is no longer a structural concern. Once there, it is met by an Orbital Airship, a multi-KM low pressure lifting body dirigable with active (energy using) means of reducing skin drag. With no gravity losses due to a near-zero weight, and the ability to balance drag and aerodynamic lift in the upper atmosphere, it can spend a leisurely week or two building up to orbital velocity with high ISP engines. Base Ribbons can be constructed anywhere, and a low altitude airship can be flown in FROM anywhere, giving this approach the same flexiility and a significantly higher payload capability (being infinitely scalable) than the S/S SSTO above, at the cost of long flight durations. Orion Nuclear Pulse Drive- North Korea demonstrated this launch capability -once-. China lifted it's protection of north Koea so the US could make sure North Korea never tried anything like it ever again. (While North Korea had the political will to nuke their own territory to reach space, China was less happy about receiving the wind-flown fallout) Chimborazo Rail Launcher- a simple mass driver going up the western slope of the tallest mountian on the equator. Can launch any payload that fits in the mouth and can take the acceleration needed to reach 11 Km/sec in only 160 KM from the western seaboard. Mutistage Reusable Beamed Microwave Thermal Rocket- A traditional style heavy lift rocket using beamed power to use a Thermal Rocket to put heavy payloads in space quickly, on any trajecory, from any location with line of sight to a microwave launch battery. Despite an improved efficency over 21st century rockets, it is still the most expensive option... but has the most marks in the "pro" column. -Earth/Moon SoI- Low earth transfer station: handles passangers, cargo, and fuel for earth launch vehicals and space transfer vehicals Momentum Exchange Tether: (to be explained later- though suggestions welcome) Geyosynchronus Kessler Ring/Geostationary Stations: partially cleaned up after a major disaster. Newer launch vehicals make fewer, larger instalations reasonable, and a modular design was instituted to make expansion more cost effective than creating a new debris ring. Lunar L1 Tethers: three tethers passing through the earth moon L1 point, one to the lunar equator directly "below" the L1 point, the other two near the north and south poles, with trams available to reach the polar mining bases. The tether passes beyond the L1 point far enough that you can release a cargo (either from the lunar bases or the L1 station) into an atmosphere- skimming trajectory, setting it up for an aerobreak into either LEO or reentry-to-surface. Higher up the cable will release a payload in a Cable-to-Geosynchronus Orbit transfer, though this one requires rocket breaking when it reaches the GS Stations. at the L1 station, there is a zero g docking station to handle Interplanetary Transport Network traffic. Lunar L2 tethers: The mirror of the L1 tethers, they also have trams to the polar stations, making overland transfer possible though not as efficent as an ITN flight. This outbound tether ha launch points from the L2 station, as well as Mars transfer, Mars Cycler Transfer (which is silightly more energetic) Venus and Venus Cycler transfers, and if materially possible a Jovian Transfer from the tip of the outbound tether's counterweight. -Solar SoI- Mars Cyclers: a set of solar-orbit stations in a Earth/Mars harmonic orbit- every 5 orbits a cycler passes one planet just outside it's SoI, and then passes by the other planet. 5 of the cyclers pass Earth before Mars, the other 5 pass mars before earth, so a round trip is possible. These stations have heavy radiation shielding, renewable life support, and zero-boiloff tanks for cryogenic fuels- everything that would be nice to have in an interplanetary vehical but you dont have the mass budget for, you dock with a Cycler and use theirs. Cycler orbits at a bit more DV heavy than a minimum energy transfer, but again, you dont need to carry your own stuff, so it's often a winning proposition. Venus Cyclers and Jovian Cyclers: Similar to the mars cycler but with different harmonics. May be only partially complete by the 31st century due to little drive for human presence at Venus or the outer system. Interplanetary Transport Network: Just read the link. It's a complicated, but very low energy concept that relies on an understanding of Lagrange points. -Mars SoI- Phobos Cable: If materials permit, a direct jovian transfer would also be a good option. -Venus SoI- Soletta: A large solar station at the Venus-Sun L1 point. Actually just a bit on the Sun side of the L1 point, but using solar wind to stay balanced. The largest solar power plant in the System, it has a number of lasers and masers for pushing solar sail craft and thermal rockets elsewhere in the solar system, as well as beaming power to the venus instalations and manufacturing "bulk" antimatter (milligrams even!) in it's free time. It's so large, it blocks a measurable percentage of Venus's sunlight. While many of these applications would be more efficent in Mercury orbit or the mercury L1, Venus's atmosphere and resources make it a more useful gravitational anchor when it comes to trade with the rest of the solar system. Atmo-Synchronus Stations: While Venus itself has a day comparable to it's year, it's atmosphere circles it every 48 hours or so, the Atmo-Synchronus stations stays above the cloud-factories, beaming power down to the night side. Cloud Factories: O2 blimp-cities 50km over the surface, just above the Sulpheric Acid clouds. Using solar and beamed-microwave power, it cracks captured sulpheric acid and atmospheric Co2 and turns it into methane rocket fuel, O2, and bulk carbon and sulphur, the excess of which is dumped to the hellish landscape below. Between the solletta and the cloud factories, Venus is theoretically being terraformed... but that's just a side benifit of the mining process. -Jupiter- Jovian Slingshot: the classic answer to outer system exploration Io Power Station: This one takes a little explanation- it's a massive Electrodynamic tether "falling" to Io while "dragging" on Jupiter's magnetic field, balancing these two forces to extract "free" power from Io's orbital velocity. This is possible because Io has no magnetic field, so an Electrotether gravatationally bound to Io is still interacting with Jupiter's magnetic field. How much power depends on how large you build your station and how close you get to Io. Galilean research stations: basic scientific outposts above and on Io, Europa, Ganymede and Calista. I dunno if tethers are reasonable for the ground stations, but mass drivers should be. ----------------------------- Did I miss anything interesting? what should I have added? What do you think is total bullcrap?

Better, an Alcubierre Drive powered through a wormhole. Smaller vehical doesnt need to carry it's own exotic mattter production, and you move a functional wormhole exit at FTL- equivilant speeds.

This was from Febuary of last year:

can we merge the "airbreak" and the Acid Bucket into a single application? Or is there enviromental or multitasking issues with that idea? Given the energy we have available, what kind of catalists and reactions would we need to create methane+LoX out of sulpheric acid and Co2?

Which is why SpaceX is big into low-thrust High-TWR engine clusters- By building one or two merlin engine per month, they can launch only a few rockets a year and still benifit from a degree of mass production.

For reentry, you wan the opposite effect, the bumps of a training golf ball. Also, it may require spinning, but if not, it may be of benifit to spaceplanes, that spend ore time in higher drag regines.

So it sounds like we've got this awesome plan for ISRU. Great. What do we need to make it work? Someone mentioned 10-20 km of acid-resistant cable , with what amounts to an acid collecting bucket at the bottom. What kind of catalists, energy, and facilities are needed to crack acid into useful components, how do we separate them, how do we store them?

I'v seen that before, and it was suggested as one of the options for the Comunity Cubesat payload. Personally, I feel that earth orbit is not electrotether's true calling. The real answer is outside the Jupiter-Io trailing lagrange point (L4, I believe) Place the satelite inside Io's gravitational sphere of influence. the satelite wants to fall toward Io, and Io (ever so minutely) wants to fall back to the satelite. But Io has no magnetic field, so the satelite is still withing Jupiter's MAGNETIC sphere of influence. With an electrotether, the satelite can drain it's orbital velocity into "free" electricity, until it deorbits itself. -But if you BALANCE these effects...- you are slowly draining -IO's- orbital velocity into electricity by gravity trator. Free electricity that will last for millions of years of continious use, in the outer solar system and local to the Jovian moon system...

On the other hand, most of the applications where hydrogen leakage is a worry involves a high pressure differential. How much hydrogen leakage would you expect in an equal-pressure system such as a dirigable? Hydrogen blimps were used in war... If planning a long term mission, it might be better to send new dirigables with hydrogen, and replace the hydrogen with heavier oxygen on site, using the displaced hydrogen as feedstock for various useful reactions in venus's atmo.

Is there one of these that's been updated with FAR's new skin drag?

Better than a huge pressure suit like you would need for mars, even allowing for the gravity difference.

With a teflon scuba tank, sure. Pressure and temperature is right, just not the gas mix.

Eeloo should have a thin, dense atmosphere that doesnt go above the canyons. With oxygen.

To be fair, SOME form of orbital infrastructure should be in place- The apollo service module counted as orbital infrastructure while the lunar lander was on the surface, after all. If your parking yor transfer vehical in the long term, especially a reusable transfer vehical, a servicing (and refueling) capability would be useful. Resource production on earth, refueling station in orbit to top off a transfer vehical, Transfer vehical parking/fuel depot over mars, ISRU on mars. By halving the DV requirements of the transfer vehical (by refueling it in mars orbit) you can increase the payload by the mass of the fuel you save.