Follow Slashdot stories on Twitter

 



Forgot your password?
typodupeerror
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×

Comment Re:Can only be played on Apple products (Score 2) 74

Everyone wants to own both the distribution channel and the content being sold over that channel. Netflix, Amazon, Hulu...

They all want their own programming so that going to a different store means losing access to content. If Apple's content does appear on Netflix, you can be sure of two things: (1) it'll be old episodes and (2) their programs will include melodramatic, never-ending story arcs.

Comment Vocational training for young kids is a waste. (Score 5, Insightful) 193

Who knows what jobs will be available in twenty years, between AI and offshoring? Coding doesn't look like a sure thing at all.

If you are going to focus on a skill, focus on ones that serve in that kind of future environment: being able to pick up on human context and nuance; to decode, no just the literal level of communication, but implicit levels of communication. Because even if AI and foreigners take our coding jobs, somebody is going to have to lay out specifications, and that take imagination and subtlety.

And you know what would be really, really good for developing those kinds of skills? Reading and discussing books.

Comment Am I the only one... (Score 4, Interesting) 128

.... who can't help but cheer at my screen when they nail one of those landings? Now I finally understand how sports fans feel when they watch a game and do the same thing ;)

One thing nobody can deny about them is optimism. ;) Seriously, their IPS numbers are, pardon the pun, out of this world. $200k per booster launch. $500k per tanker launch. I mean, really? Good luck with that. No, seriously, good luck with that; I won't be expecting anything close to that, but please by all means prove me wrong ;) ITS would be a great system to have, I've been playing around with some Venus trajectories with it recently. Looks like it can do a low-energy transit with nearly 300 tonnes of payload from LEO and back again with the same, over 400 if starting at a high orbit - but from an economics perspective the high energy transfers actually make more sense.

I noticed a lot of people were confused about why Musk wanted the trips to be so short and was willing to sacrifice so much payload to do so - many assumed it had to do with radiation or something. But the issue is, when your craft costs so much but your launch costs are cheap, you can't have it spending all of its time drifting in deep space, you need to get it back for a new mission as soon as possible. There's a balancing point, in that if you try to go too fast, you reduce useful payload below the point of making up for it with going faster - but a minimum energy trajectory is just not optimal when the ratio between launch costs and transit vehicle cost is so extreme. I come up with the same thing from Venus as they were getting for Mars, although for the Venus case you end up aerobraking to a highly elliptical orbit rather than to the surface for ISRU refill (you need ISRU, but for the ascent stages, so it's not realistic to do so for the return stage in the nearer term). So for Venus they get no refill like on Mars, but they also don't have to do a powered landing nor do an ascent on return - it's six of one, half a dozen of the other. Both are quite accessible with it.

Comment Re:Great strides (Score 1) 128

It depends what you mean by "refurbishing"; each element is different.

The solid rocket boosters, for example, suffered a hard impact into salt water. They then had to be fished out of the water. And of course you don't just "refill" a SRB, they have to be taken apart and recast, then put back together.

The ET is disposable, and had to be rebuilt from scratch.

The orbiter was legitimately reusable, but with design flaws.

I don't blame the shuttle program - they were sort of pigeonholed into this dead end by circumstances. The concept came about during the heyday of the Apollo Programme, when NASA budgets were serious. It was supposed to be a much more reusable, much more maintainable, and somewhat smaller system. It was supposed to then have a huge flight rate supporting all of these big projects that were on NASA's docket, including a permanent moon base and a huge manned orbital station dwarfing ISS, which was supposed to replace Skylab.

But of course, Vietnam and the realities of having soundly trounced the USSR in the space race led to their budgets being slashed, which pushed the program into ever more untenable positions until it was nothing more than a jobs programme. Forget full flyback reusability of all parts. Forget the titanium frame for the shuttle, which would have let it run hot and thus not required so sensitive of a TPS. Go begging for money and be forced to modify the design to meet Air Force requirements, pushing you into an inferior design position. On and on.

If I'd fault them for anything, it'd be for going straight for a full reusable workhorse rather than a small-scale pilot programme first. But those were the days of optimism. Optimism which only recently seems to start being regained.

Either way, the Falcon boosters are a very different beast. A vertical soft landing is hugely different from the SRBs, yet the thermal issues are far easier than with the Shuttle. And the Merlins were designed from the start under the principle of preventing the need for a full teardown. That doesn't mean that they will be cheap to reuse. But it does mean that they have the possibility of it.

I do think SpaceX had a rather clever strategy, in that while their goal was reusable, they made a rocket that in the process was cheap as a disposable. So they could get volume and flight history while working on getting the kinks out. They may have flown too close to the sun with the densified propellants and (externally) unlined COPVs, but obviously, with a company like this, their whole existence is to push the envelope.

Comment Re: Awesome (Score 3, Insightful) 128

Most of Europe agrees with you. And even the US agrees with you up through high school plus with various forms of assistance for college, including state-subsidies, particularly for state colleges, and federal subsidies (direct subsidies, tax credits, and tax breaks), roughly $80B/year each. Pell grants alone cost the government $35B.

Comment Re:don't be too quick to judge (Score 1) 286

yes India has terrible controls on their antibiotic use, but remember that US farmers are using large amounts of antibiotics too keep their overcrowded livestock from dying too soon.

India is a country with a median annual income of $616. With 1.2 billion people, well, a lot of things like providing medical care are going to be tough. We're headed that way too. While per capita GDP growth has recovered from the Great Recession, median income has declined.

Comment Re:No Gut no Glory (Score 1) 66

This is kind of an oversimplified view of affairs as they now stand.

The newer players aren't competitors to NASA; they're competitors to NASA's traditional vendors. They probably wouldn't exist were it not for government policy to encourage and support more independent, entrepreneurial approaches to launch system development and management.

Comment Re:No Gut no Glory (Score 1) 66

To be clear:

  * Getting the failure rate down in the lower tenths of a percent or better is what they need to be able to ~10x their launch rate and still be economically viable, since a pad explosion will leave them stuck for just as long and scare off just as high a percentage of their customers whether they're launching 12 a year or 120.
  * SpaceX wants to have reliability like airplanes, and has talked about this frequently.
  * What they want to achieve, and what they need to achieve, are not the same thing. They do not need to achieve airplane-like reliability for the Falcon 9 to be viable.
  * That said, if they ever want to achieve their ultimate IPT plans, they absolutely will need airplane-like reliability. Because they're calling for ~1000 launches per booster on that thing with a turnaround cost of ~200k. They really cannot have anything go wrong with it.

Comment Re:No Gut no Glory (Score 1) 66

It most certainly would be extreme reliability by the standards of the launch industry. The only ones that have better reliability than that that don't have nearly a statistically significant enough number of launches under their belt to assert that. Aka, "they haven't had a failure yet but nowhere near the several hundred launches required to assert a lower fraction of a percent or better failure rate".

We're not talking about airplane reliability here, we're talking about economics (the title of the article is "SpaceX Accident Cost it Hundreds of Millions"). Airplane-like reliability is for the future. We're living in the present.

All COPVs use an inner liner. The problem with SpaceX's COPVs is that they have no outer liner to separate the carbon fibre from the LOX. Outer liners are optional. SpaceX didn't use one. They lost a rocket because of it. They're going to keep trying doing without one. I really hope it doesn't cost them another. CF and LOX aren't fast friends.

Slashdot Top Deals

Support bacteria -- it's the only culture some people have!

Working...