Cost of fuel
I had the same thought at first but 100kg of fuel is hell of a lot cheaper than 100kg of rocket engines. Or 100kg of avionics.
34 posts • joined 27 Oct 2006
"...unlike every other..."
Someone is going to be first - it might be BT, it might not, but hit a wall often enough and eventually it will fall.
"...lardy-bottomed monopolist BT..."
Ignoring the fact that even in the UK they aren't a monopoly, on the Global scale they are "just another player" in the world market.
"...they saw everybody piling into BPO and infrastructure support, so they had to do that too as BT Global Services, and that all ended in tears..."
Largely due to the bottom falling out of the world economy, a lot of other players got burned too.
"Did Japan license the design from the US or Russia, or perhaps ESA? Because those are the only ones I know of that have serviced the ISS."
Japan developed the HII-A used in this launch into the HII-B that has successfully launched 2 HTV service vehicles to the Space Station. The HTV is actually more capable than either Progress or ATV since it allows full-sized racks to be delivered to the station.
Not a stupid question at all: there are several designs of reactors that have passive cooling and/or fail-safe designs.
For example in a CANDU reactor a loss of power will result in control rods automatically dropping into the reactor, stopping the reaction. A liquid salt reactor (not yet commercially available) has a 'thermal plug' at the bottom of the reactor. If power is lost, the plug will 'melt' and the reactants will flow into storage chambers below the reactor.
There are a lot of "He's a Luddite!" type comments, but most of them seem to miss the point. Mr Livingston is paid to make money for BT's shareholders. If he can't make the business case for the *massive* investment that would be Fibre-to-the-Home then he can't make it - largely because, unlike Virgin, he can't tie the customer into paying BT for the use of that fibre.
That's where his 'monopoly' comment was aimed - squarely at VirginMedia.
The problem with hybrid motors like the one SpaceDev provided for Space Ship One is that while their ISP compares favourably with conventional solids (250s v 270s for the Shuttle SRB), they don't really scale well for thrust. If you want to increase the thrust of a solid, you just make it longer (most solids burn along their entire length from inside out), while with liquid (or gel) propellants you increase the flow rate by using bigger pumps.
A hybrid requires you to increase the flow of oxidizer (which requires larger pumps) *and* increase the area of fuel (make it longer) - not to mention the difficulty of ensuring proper combustion along the entire length of the rocket.
"No. The ISS and Hubble are in different orbits. THe Shuttle can't travel from one to another."
Further to that, a back of the envelope calculation made in another forum gave the result that getting between the orbits of ISS and Hubble would take nearly as much propellant (~80%) as it takes to get into orbit in the first place!
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