I feel if the 1st stage booster had an attitude control system toward the top like the BRAHMOS missile [1], the lean could've been corrected to at least have the rocket be upright when it impacted the platform. Although the choice to add an attitude control system would probably take up more space and add mass which is critical for a stage rocket.
SpaceX: “Close, but no cigar. This time”
141–150 of 279 posts
Re: SpaceX: “Close, but no cigar. This time”
#142Earlier quoted context omitted.
You joke but a future were corporations control ICBMs to their advantage is a realistic worry.
I'm trying, but not succeeding, to imagine a non-fiction situation where a corporation has any business advantage in owning and/or controlling an ICBM. Can you expand on your comment? What would a corporation do with this, other than to perhaps implement same day delivery of packages around the globe?
Space launch systems are so deeply dual-use it's not even funny. Orbital rockets are very similar to early, low-readiness ICBMs - modern systems prefer solid fuel, since they can be safely kept fueled for longer periods of time, but aside from that the biggest differences between a Falcon 9 and an ICBM is how ridiculously overpowered the Falcon is, and its lack of re-entry countermeasures (MIRVs, decoys, etc.). Which is why anyone working at a company like SpaceX is subject to the same technology export restrictions as weapons companies.
For example, if SpaceX can get e.g. the Dragon capsule to land with a reasonable accuracy on thrusters, and then put a warhead in it (or multiple warheads) , that's quite a capable weapons system right there. In fact, it's even capable of fractional orbital bombardment, which was considered so destabilizing during the Cold War that it was specifically banned in SALT II.
tl;dr - Elon Musk will, within a couple of years, control a system that can be adapted into an ICBM within a very short period of time and with minimal investment.
Re: SpaceX: “Close, but no cigar. This time”
#143Re: SpaceX: “Close, but no cigar. This time”
#144Maybe OP, but if Elon Musk makes actual technical contributions to his companies, I'd be super impressed.
Well he has two undergraduate degrees, one in physics, and was accepted on to a physics PhD programme, I don't think he's just a front man.
Re: SpaceX: “Close, but no cigar. This time”
#145Earlier quoted context omitted.
Well, Elon Musk said talking about hyperloop was like shooting his own foot. It was a premature idea. But the interesting part is some(more than some) people are actually trying trying to come up with a real world implementations of hyperloop and so far their verdict is 'it's doable' and they are working on it. And these people are engineers from reputed companies around the world. I don't particularly like the conce…
"Premature idea" is probably better phrased as "not feasible on technical grounds." Even tlb said it has huge problems. The steel expands in summer due to heat. Where does it go? Roads can expand using those interlocking teeth things, but hyperloop has to remain a closed system. Oh well. Everyone should dream once in awhile. EDIT: So... is this incorrect?
Humans have been engineering expansion joints for various types of continuous structures for well over a hundred years, including sealed pipelines.
The new design requirements and constraints posed by the Hyper Loop concept just increase the complexity of the problem. Certain engineers love this kind of challenge.
Re: SpaceX: “Close, but no cigar. This time”
#146Earlier quoted context omitted.
> The steel expands in summer due to heat. Where does it go? Roads can expand using those interlocking teeth things, but hyperloop has to remain a closed system. Feel free to disagree with whether or not the approach outlined is feasible, but this is specifically covered in the whitepaper. See page 5, section "Earthquakes and expansion joints" as well as page 28, section 4.2.3 "Pylons and tunnels".
To clarify, tlb's comment was in direct response to the Hyperloop Alpha whitepaper: https://news.ycombinator.com/item?id=6201728#up_6202327 He doesn't properly address thermal expansion of the entire system. A long straight steel tube from SF to LA will expand a total of 300 meters over a 40C temperature change. Where does it go?
And my response is the same: See those sections.
Re: SpaceX: “Close, but no cigar. This time”
#147I feel if the 1st stage booster had an attitude control system toward the top like the BRAHMOS missile [1], the lean could've been corrected to at least have the rocket be upright when it impacted the platform. Although the choice to add an attitude control system would probably take up more space and add mass which is critical for a stage rocket. [1] http://i.imgur.com/5RWkvem.gif
It does (https://www.youtube.com/watch?v=DgLBIdVg3EM), it just ran out of hydraulic fluid in this case.
Re: SpaceX: “Close, but no cigar. This time”
#148This was "close?"
Did you watch the same video I watched? They practically had the thing hovering on the barge. All that failed was the angle!
I'm guessing the poster thought this was a failed take-off.
I wasn't "in-the-know" about this being a return / landing until I got to this comment section.
Re: SpaceX: “Close, but no cigar. This time”
#149Earlier quoted context omitted.
See my comment above - the expansion is specifically addressed. If you're going to criticize it, at least read the full whitepaper first. > But it would need to be very strong lining in order to prevent any leaks between the segments. The entire point of not requiring vacuum is to avoid having nearly as strict tolerances for leaks.
It's a "reduced-pressure tube." A leak is still a big deal, isn't it? Regardless, the core structural engineering is the focus of the criticism, not whether it might leak. Also, since Space X's whole point is to compete on cost savings, it was a little strange to hear cost projections that were so optimistic.
The entire purpose of the design is explicitly to keep the tolerance for leaks at a level where, to quote the whitepaper "standard commercial pumps could easily overcome an air leak and the transport pods could handle variable air density"
Section 4.5.4 otherwise covers this, and does point out that for large leaks, braking would be required, but smaller leaks are intended to be dealt with as part of regular maintenance, with no indication that it'd need to affect operations.
> Regardless, the core structural engineering is the focus of the criticism, not whether it might leak.
That may be so, but most of the criticism I've seen of it appears to just ignore large sections of the whitepaper.
EDIT: For example, with respect to handling expansion/contraction, consider that the world has gas and oil pipelines that has to deal with far worse conditions without leaks.
Re: SpaceX: “Close, but no cigar. This time”
#150Earlier quoted context omitted.
"Premature idea" is probably better phrased as "not feasible on technical grounds." Even tlb said it has huge problems. The steel expands in summer due to heat. Where does it go? Roads can expand using those interlocking teeth things, but hyperloop has to remain a closed system. Oh well. Everyone should dream once in awhile. EDIT: So... is this incorrect?
"Imagination is more important than knowledge." - Albert Einstein
Despite down votes, I still strongly believe the idea outweighs the blame for not thoroughly answering all technical questions.
And as others have already pointed out that the technical problem isn't as big as it sounds.
Also Elon Musk has announced to build a 5 mile test hyperloop track in Texas yesterday.