Just ran the math, an active decent profile from LEO adds 1.5kg of fuel for each kg of dry mass.
This may not sound like much but it adds up quick when you take into account the average mass of a space craft mass; assuming this would be planned to carry people the lowest I'd guess for a final design would be around that of the mercury capsule at 1,360kg, on the high end it could be comparable to the shuttle at 68,585kg+payload. That would mean between 2040 and 102877.5 extra kilos of fuel for a ship with no cargo.
If we assume the same maximum payload as the shuttle(25,060kg+68,585kg for the ship itself) it would need 187290kg extra. That's almost 20% of the mass of the ISS in fuel over what would be needed for a passive decent.
edited 14th Oct '13 1:00:27 PM by jaustin89
I'm not sure it's intended to descend actively all the way from LEO. The first stage is intended to work as the Grasshopper does, the second is supposed to align with the launch site and then re-enter the atmosphere, presumably with a controlled descent to the launch site - this is around 24 hours post-launch.
Personally, I'm not sure how SpaceX do it, but they reckon that their re-usability means a 30% reduction in payload. Their design uses a deceleration burn, then a second burn towards the end of the flight to control the landing. They've already done this successfully once over water, with the Falcon 9 rocket. They plan to try again with the next shot in February 2014.
TOW has more details
.
edited 14th Oct '13 1:18:16 PM by Achaemenid
Schild und Schwert der Partei![]()
I suppose the most realistic thing to do here is to assume that they know what their doing better than I do, since they're aerospace engineers and I'm not (yet).
Ive heard of using H2O2 as a fuel but I don't remember hearing anything specifying it's use (aside from early stuff like the V2).
edited 14th Oct '13 1:42:33 PM by jaustin89
NASA reopening doors, getting back online after shutdown ends
Orbital Sciences Pod Cynus
Loaded with trash and shoved back into atmo.
NASA's super fast laser communication system.
Japan tests space cannon
This is why I love Japan!
edited 24th Oct '13 9:01:14 AM by tricksterson
Trump delenda est
It's been done
, by (who else) the Russians.
edited 24th Oct '13 9:26:07 AM by Achaemenid
Schild und Schwert der ParteiGot some questions for a book I'm writing:
- Is six months a realistic length for a one-way Earth-Jupiter flight? Clarification: Ship about the size of London, using a big-arse fusion rocket.
- How tall would a space elevator on Europa have to be?
- What useful gases could be extracted from Jupiter's clouds?
- If there were fish on Europa, could we eat them?
- Where can I find a map of Europa?
edited 25th Oct '13 3:51:37 PM by optimusjamie
Direct all enquiries to Jamie B Good

It's very difficult to combine vertical takeoff/horizontal landing efficiently. The shuttle tried that, and basically no one was satisfied with the results (you will notice that none of the private companies are trying to model the space shuttle). The wings ruin the aerodynamics of the vertical flight, slowing the craft down, wasting fuel and exposing the winged craft to damage on the way up (as everyone knows).
That said, I dont know why no one has tried retractable wings with a VT/HL design.
I'm done trying to sound smart. "Clear" is the new smart.