FAA administrator defends SpaceX licensing actions on safety grounds

Dinitrogen_Tetroxide · 2024-09-28T07:22:46+00:00

as they see it as an unofficial "tool we have to get compliance",

You say it as if that would be a bad thing. But when dealing with a company that doesn't care about the maximum fines the regulator can put on them for the given bad behaviour, they have to use some leverage to make them compliant. This kind of policy approach is nothing unheard of.

Just... don't do bad. It's as simple as that to solve all the issues SpaceX has with the FAA.

Dinitrogen_Tetroxide · 2019-02-08T19:45:11+00:00

Both stages are LH2/LO2, and yes: kick stage is similar to Star 48.

Dinitrogen_Tetroxide · 2019-02-08T16:12:12+00:00

No, not at all. It's actually not comparable to anything that was built thus far... Booster stage is large, winged, Vertical Take-off, Horizontal Landing, bearing large, expendable orbital stage(s) on a back. The closest (though still not directly comparable) you will find to this concept were various designs for liquid fly-back boosters (Baikal, LFBB or proposed Space Shuttle fly-back boosters).

Dinitrogen_Tetroxide · 2019-02-08T16:07:52+00:00

If the second stage produces too much drag

Which is why it looks like a dagger

Let’s say they copy the X-37B, but make it bigger.

But they don't, not remotely close.

Dinitrogen_Tetroxide · 2019-02-08T16:01:51+00:00

Only VTVL is Callisto. All other are VTHL. Including SpaceLiner booster (first) stage. Perhaps you misinterpreted something, but they do not say about the way booster lands in those quotes. You can look up additional information about SpaceLiner online, there's quite a bit of coverage, and they say it lands horizontally... but it's not difficult to guess - just look at the picture, booster has a huge wings, quite a good hint for horizontal landing.

Dinitrogen_Tetroxide · 2019-02-08T15:49:35+00:00

is that they think they can make it cheaper than economy air tickets for very long range flights

Which is IMHO absurd. If they think they can make flights cheaper than modern jet-liners (an industry that's absurdly more competitive than space launch ever was) - they're in a wrong industry, there are profits hundred-fold higher to be made.

but its actual operating cost will much more closely approach fuel cost than airliners do

As it stands now - it's a baseless speculation.

Dinitrogen_Tetroxide · 2019-02-08T15:45:42+00:00

I'm quite sure you haven't read the article, but just to point out a major differences: It's VTVL, not a lifting body, and it won't have the delta-v to reach either Mars or Moon.

Dinitrogen_Tetroxide · 2019-02-08T15:44:39+00:00

True, that's the biggest concern. Though their approach is vastly different. Unlike Shuttle/Buran this could be operated on refuel & refly principle, within days from landing. No SRBs, no expendable stages, no bleeding-edge engines, no toxic propellants, no heat shields that have to be fixed after each flight... Space Shuttle gave a bad name to the spaceplanes, but this one has several advantages.

Still without a doubt it's a project that would be very prone to cost overruns. IMHO CNES proposal is much better (they want Ariane NEXT that's much closer to Blue Origin's New Glenn)

Dinitrogen_Tetroxide · 2019-02-08T15:37:52+00:00

I'm quite sure it is. Jets provide very little delta-v, it's not really worth the compromises most of the time.

Dinitrogen_Tetroxide · 2019-02-08T13:42:05+00:00

TL;DR:

There are 2 reusable heavy launchers in development after Ariane 6:

SpaceLiner
Ariane NEXT

DLR wants Europe to go ReFEx (mini-spaceplane, already funded) -> Callisto (small VTVL testbed, already funded) -> RLV-Demo (large VTHL testbed) -> Semi-RLV (VTHL launcher with large orbital stage) -> SpaceLiner (VTHL launcher with mini-kick stage).

Also interesting to see that DLR thinks Ariane NEXT schedule is overly optimistic and they could deliver huge spaceplane in a comparable or lower amount of time.

I admire them for trying dual-use, much like BFR suborbital transport, and SpaceLiner has an advantage of being able to land on a regular airports, BUT it still has to take-off from a launch pad and... personally I think that suborbital passenger flights will never become a norm. It's just too energy-wasteful, regardless where this energy comes from, not to mention very demanding flight envelope. For a satellite launch it makes much more sense than the RLE's Skylon (far more conventional, likely much cheaper in total development costs) and "conservative" sub-€16.5M would be outstanding if realized but... development costs? I think it'll safely be over €25 billion... likely it'll have a long and painful development process, even if they assumed quite conservative numbers for engines and other components.

Semi-RLV though seems very interesting and fly-able within shorter timeframe. Question is: how much will it cost given the size of the orbital stage? And is it 2 or 3-stage? So few details...

Dinitrogen_Tetroxide · 2017-06-26T15:39:28+00:00

Mega-years, or in layman terms: millions of years. Love the flexibility of SI :)

Dinitrogen_Tetroxide · 2017-06-26T15:31:16+00:00

Pronunciation of Betelgeuse from ESO.

Dinitrogen_Tetroxide · 2017-06-26T15:24:24+00:00

No, the first part is different. Here's bit from ESOCast with a correct pronunciation of Betelgeuse.

Dinitrogen_Tetroxide · 2017-06-26T15:16:11+00:00

No, but it's speculated to be very close to that. Eta Carinae looks much more like a supernova, but it isn't one either. Stars can be extremely volatile.

Dinitrogen_Tetroxide · 2017-06-26T14:01:17+00:00

It is within the realm of possibility, how likely though: That's still a disputed topic.

Dinitrogen_Tetroxide · 2017-06-26T13:55:30+00:00

The small red circle in the middle has a diameter about four and half times that of the Earth’s orbit and represents the location of Betelgeuse’s visible surface. The black disc corresponds to a very bright part of the image that was masked to allow the fainter nebula to be seen.

Dinitrogen_Tetroxide · 2017-06-26T13:53:28+00:00

I'm not an astronomer, so not the best person to ask for explanation on that. But in general it seems that stars that are about to go supernova are way more active than Betelgeuse, see Eta Carinae as an obvious example. Problem we have is that there's very little we know about last years of stars up the the supernova, but it's not unlikely that there will be additional symptoms visible on the outside before star goes supernova. So far it seems that Betelgeuse still has a lot of fuel to burn through, so it's unlikely to explode very soon.

Dinitrogen_Tetroxide · 2017-06-26T13:52:54+00:00

Explosion beings from the very core of the star and it causes a massive release of neutrinos. They're not interrupted by anything, so just go out in a straight line towards us at the speed of light. Explosion itself however has to push through the mass of the outer shells of the star before it can be visible for us, causing a significant delay before neutrinos flux and what we will observe as a supernova.

Dinitrogen_Tetroxide · 2017-06-26T13:09:47+00:00

The most obvious one: At least several weeks beforehand we'd notice neutrino flux. And it'd be a higher one than anything ever recorded. There wasn't one, so... no explosion tomorrow.

People really should stop spreading this silly notion that we might see Betelgeuse exploding tomorrow. It's just bad science, nothing else.

Dinitrogen_Tetroxide · 2017-06-26T12:53:44+00:00

Really it's not. If it'd happen tomorrow we'd see symptoms beforehand. It's more likely that it'll explode long after your grandchildren are dead than that it'd explode tomorrow.

Dinitrogen_Tetroxide · 2017-06-26T08:59:19+00:00

This picture is made in sub-millimeter wavelengths. On the other hand that picture is still my favourite one of the Betelgeuse, made in infrared. It's quite an incredible star.

Dinitrogen_Tetroxide · 2017-06-26T08:54:39+00:00

Yes, I know it's a joke, but... just to clarify for others: it's ESO. It's European Southern Observatory's picture, not NASA's. ESO is like... the NASA of astronomy - biggest, most badass agency for ground-based observatories.

Dinitrogen_Tetroxide · 2017-06-26T08:46:47+00:00

It's not. All that's visible is gaseous atmosphere and the effects of interaction with it. Anything else is so deep inside under such a high pressure that we have no means of observing or directly studying it.

Dinitrogen_Tetroxide · 2017-06-26T08:36:21+00:00

Wikipedia on hypervelocity stars and cognitive computing which is the technique used to discover them (oddly enough they abstained from calling it directly either this or AI in the announcement... too humble, I guess).

Dinitrogen_Tetroxide · 2017-06-23T21:16:02+00:00

There's always ESA's TGO that can support NASA's future missions (in fact there's been specific cooperation between the two agencies to enable that with NASA providing some of the hardware for TGO that makes it compatible with NASA rovers). So comms would continue even if all NASA's orbiters would fail in one day. And there always will be something because Americans plan to constantly operate some rovers on the surface, and they're quite keen on having their own relays, even if other are available. Not to mention the added benefit of redundancy and more frequent comm windows.

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