I don't see a mention of whether the previous relights succeeded or not. I'm guessing they did succeed, but the center booster had to perform a higher number of relights than a Falcon 9 booster due to its higher speed.
The excessive TEA-TEB use may have been caused by an unrelated engine issue. In any case, Musk reported the fix is 'obvious'.
So, an equal number of "relights" of the entire rocket but more engine relights, and engine relights are the relevant unit for ignition fluid consumption.
The unique part of the GovSat "failed to expend" mission a few weeks ago was not cutting off the outer two engines some time before hitting the surface, not that it used three engines at all.
That's a problem because the amount of igniter fluid depends on the air pressure in the rocket chamber, and it was not possible to determine this exactly beforehand through either testing or modeling. So they took a guess and it turned out wrong, but they got lots of data on the rocket chamber pressures, and will adjust accordingly in the future.
"Southwest has 'multiple glycol deliveries' scheduled for Monday and expects to resume 'close to normal operations' at Midway, she said."
Southwest fluid issue is likely a logistics failure.
I don't see them as related.
SpaceX is amazing and I'm glad they're doing the hard stuff.
I can't find any info on how much TEA-TEB is carried on-board, only that it's ground supplied for initial launch with the on-board TEA-TEB being used only for restarts.
(I'm not even an amateur rocket scientist: I just googled all this.)
Regardless, this was the cause of the violent yaw/roll action associated with an unstart (loss of thrust). When the intake was reconfigured the afterburner had to be re-lit and in a J58 this requires TEB. So while TEB was not used to correct the unstart it still had to be used after an unstart.
Someone doesn't understand precision.
(That's 100 meters, so "about 300 feet".)
To me at least, "about 328 feet" seems okay. It gives you more precision than "about 300 feet" while still letting you know that it's not exactly 328 feet.
The best part was that in the websites for some some markets they converted the very precise imperial figure back to metric and claimed something that was close to the original rounded number number but off enough to be extra weird (like 2,999 kg of silver).
Well for that, you'd want to change the hull type from a barge to a spar buoy. Given that, there's no reason why they couldn't do both.
(Permanent structures in the ocean need to be spar buoys, or some other architecture that are largely immune to Rogue Waves.)
- Of Course I Still Love You
- Just Read the Instructions
- A Shortfall of Gravitas
(and doubly great for you, u/ZeroGravitas)
My all-time favorite is "Ultimate Ship the Second".
I'm biased by my love for 'The Hydrogen Sonata,' but my favorite will always go to the Mistake Not...
Which is short for Mistake Not My Current State Of Joshing Gentle Peevishness For The Awesome And Terrible Majesty Of The Towering Seas Of Ire That Are Themselves The Mere Milquetoast Shallows Fringing My Vast Oceans Of Wrath.
I wonder if the same thing happened here. Maybe Elon saw someone complaining about his irreverent ship naming (both the ASDS and the "BFR") and decided to respond with this.
a rocket certainly moves fast...
The real trick is knowing when it's OK to break things in experimentation and the acquisition of knowledge, and when everything needs to run smoothly.
When they said they lost the core, I've been envisioning a barge with a big, round hole in the center...
If an engine relight doesn't happen, they won't hit the barge.
I think the biggest danger to the barge is a final engine relight without enough fuel, or with a guidance and nav systems failure or error.
I once saw a nice enamelled sign on a bridge stating 'Whoever programs a target on target will be promoted to figurehead prior to arrival at said target.'
(And, in that position, being the first to regret their sloppiness. Plus, they will somewhat soften the impact. Cough.)
The world is just frighteningly complex, sometimes.
The rest of the passivation will mostly be purging the engines, closing valves, and releasing pressure in the various tanks and vessels. LOX venting might take a while as it all boils off.
I've said the same before many software bugs or family computer problems that ended up being all nighters on :P
But I'm sure SpaceX will get through this,,,
"No plan of operations extends with any certainty beyond the first contact with the main hostile force."
And even the best of modeling will not guarantee that reality will behave as predicted. Suspension bridges, for example, often need some ‘tuning’ to remove resonance after construction.
Bridge engineers, knowing that, often won’t even try to spend time and money to exactly predict bridge behavior. This may be similar: they may just have thought it would be faster or easier, maybe even cheaper to do the experiment than to work on exactly modeling their engine.
(The center engine is different from the others, but it also could just be statistics, with the amount they used giving a probability slightly below 1 of igniting one of these engines, and this being their unlucky day (given that they already have quite a bit of data from earlier launches, that is not too likely, but it is something I would let an engineer look at)
Anyway, that's why they do these tests: to make the "unknown unknowns" known.
The precise amount they'll need depends on how quickly and reliably the engines restart. If the engines take a couple extra shots to light, then you may run out.
The recent "stage that lived" was testing three engines all the way to "0" (which worked fine, apparently).
My guess is the hotter than normal reentry meant the engines were a bit tougher to relight, and they burned through more starter loads than they expected.
Most recent droneship landings recently have used three engines for the 'middle' part of the burn, shutting down the other two before actually landing.
The recent GovSat launch tested a three engine burn all the way down (the first time they have tried that, AFAIK).
There was nothing unusual about the number of relights. My guess is the issue was with the difficulty of the relights.
They had the ship done and seemingly ready back in December - https://imgur.com/gallery/MQcEE
Fairing recovery has proven surprisingly difficult. I'm still fairly sure we can do it in the next six months, but the fairing is [not aerodynamic], messes with the parachute... we also have a fairing version 2, much more important than version 1 fairings.... my guess is next six months for fairing recovery. We have the special boat. .....we might even be able to catch the dragon too, if nasa wants to
Plus they're slow to manufacture, so they can increase tempo if they can get them back intact.
As I've heard it been put - "Imagine if there was a pallet of $1M in cash falling from the sky. And you knew where and when it would fall. And you'd expect the rate of 'cashfall' to increase to tens, even hundreds of times a year. Would you try to develop a system to catch it?"
They’re not quite simple.
The fairings are troublesome for several reasons. They have to be very large because they have to be larger than the payload, they have to be very strong because they have to protect the payload through the atmosphere at supersonic speeds, and they have to be very light because they ride on the upper stage, and their weight takes away from payload weight (not quite at a 1:1 ratio but not too far from it). So they are expensive because expensive fairings allow you to launch even more expensive payloads.
And in principle they are not terribly difficult to recover. The re-entry speeds are fairly low since they are only ever sub-orbital, and they are very light for their size so re-entry heating isn't a major challenge. But aerodynamically controlling them in a reliably manner to a precise location seems to be a problem.
The numbers are small compared to the rest of the game, but it's one of those things that would make life so much easier if they could just catch the damned thing.
Since the fairing has the same energy requirement as the payload (in energy/kg), it's important to get rid of it the moment it's unnecessary. If they took it to orbit (so they could leave in space), it would drastically cut down payload mass.
If you watch this part of the YouTube stream, after it cuts back to the two hosts there is a monitor at the far right center of the video that shows the continuing camera feed of the drone ship landing pad. Only part of the monitor is visible, but after the smoke clears over the next few minutes you can see the empty pad:
You can also see the surprised reactions of the hosts during these few minutes, and how relieved they were when John Insprucker joined them to wrap things up. It would have been interesting to be a fly buzzing around their earpieces to hear what the producers were telling them!
People have speculated that with everything else in the mission being so spectacularly successful, they wanted the initial news reports to be about that success instead of the one core that failed to land.
Knowing how the news works - "Here's what's wrong with the world today!" - I can sympathize with that.
Smoke on deck clears, no core visible, deck empty. Both go "oh." and after a pause, while looking at the empty deck: "we're waiting to hear what happens. [...] we'll let you know as soon as we find out" and "we'll [...] know [...] whether it's standing". All while looking at the empty pad.
They saw it didn't land, they found out immediately and didn't let "us" know. Instead they claimed it might be possible it is standing despite seeing the empty deck.
Khrunichev are out of the game. The old Proton vehicles are cheap, but they're very unreliable due to a barely-modernised 1960s design and poor construction. They flew four launches in 2017, versus SpaceX's eighteen; by all accounts their order book is looking very sparse indeed. Their new Angara vehicle hasn't flown since the first orbital test flight in 2014 and has attracted no real commercial interest.
ULA can't even begin to compete on cost. Without the capability and readiness contract from the US government, they'd be out of the game entirely. They didn't even bother to bid for the GPS-III contract. The SLS won't be ready until next year, it'll only have about 10% more payload capacity to LEO than Falcon Heavy and it'll cost at least three times as much, with no possibility of reuse.
EADS are attracting a good amount of commercial launches, but their competitive advantage is fading rapidly. Ariane 5 is reportedly 3-4x more expensive than Falcon 9 and has less payload capacity to LEO. The planned Ariane 6 will be considerably cheaper than Ariane 5, but it'll have less payload capacity and still won't be price-competitive with Falcon 9. EADS have not announced plans for a heavy launch vehicle.
Blue Origin are chasing SpaceX's tail. The New Glenn vehicle won't begin test flights until 2020, it has less payload capacity than Falcon Heavy, shows no signs of being cheaper and isn't as reusable. Even if everything goes to plan, they'll still be badly trailing behind SpaceX.
I think a lot of the excitement, for myself anyway, is that SpaceX represents the only tangible effort to bring us kicking and screaming into the space exploration age.
Despite having prices reportedly lower than any newly manufactured rockets, they are rapidly approaching parity or superiority on a number of other measurements of quality with other launch organizations.
Basically in the 1960s, it was envisioned that space launches would become routine, but they did not (the "Space Shuttle" was so named as an analogy to shuttle buses that have regular round-trip service). SpaceX is the most successful attempt since then to make it routine.
1: most other launch companies don't advertise prices
2: repurposed ICBMs are historically the cheapest way to space, but see also #1
Each of the four attempts to launch an N1 failed; during the second launch attempt the N1 rocket crashed back onto its launch pad shortly after liftoff and exploded, resulting in one of the largest artificial non-nuclear explosions in human history.
Energia's a more interesting comparison, since it's hard to know if its advertised payload was at all accurate, but it did fly. I'd say that if it could have delivered its advertised payload reliably, the design probably would have flown more than twice and would have survived the fall of the Soviet Union. I have no idea what a half-finished Buran weighs...
"If you can walk away from a landing, it's a good landing. If you use the airplane the next day, it's an outstanding landing"
In contrast ULA is higher cost but is more reliable. A great deal of their technology is older than SpaceX because they are the incumbent launch platform. They don’t really market themselves the same way due to the fact that they are profitable. The pay I believe is average and has better work life balance than SpaceX.
which is really saying something, as a lot of aerospace employers prey on the cool factor of doing space stuff to keep folks working absurd hours, for well under what they'd make doing similarly difficult work elsewhere.
Why did SpaceX spend resources to get them to safe landing then? I presume, they rather maintain their routine and maintain the success of landing the booster. It would probably be expensive to change their standard procedure.
Does any know how many times a booster can be resued? What dictates its lifetime?
The block 5 variant is designed for 10 launches in a row with 24hr turnaround. With service, over 100 launches is the goal.
That, and the best equipment to test out is equipment you know you won't need again in the future.
Case in point: It's much cheaper and less disruptive for them to lose this rocket and fix the issue than to lose a future rocket slated for reuse.
collect data + parts of the booster can be reused
"This was the pair of boosters used on the historic first flight of X to Y" looks good on a museum plaque.
The fix, he said, was "pretty obvious."
A million and one things can go wrong, and any one of them can destroy the spacecraft. Compare that to commercial air travel - where a number of unlikely events have to happen, to down an airplane.
Some time ago, there was a HN discussion about traveling from continent to continent in minutes, using a sub-orbital hop. I don't know about anyone else, but I'll pass on being strapped to a skyscraper filled with LOX and RP-1.
Airliners are fully capable of turning themselves into fireballs. It doesn't happen often because we have a lot of experience operating them. The same safety levels are possible with rockets over time.
That's true, but a 747 does not burn its weight in fuel in 397 seconds. A Falcon 9 does. It's the difference between igniting a gas barbecue in your back yard, and igniting the propane tank that feeds it. One of those things is something I do on the 4th of July. For the other, I'd prefer to be taking cover in a foxhole.
> Airliners are fully capable of turning themselves into fireballs. It doesn't happen often because we have a lot of experience operating them. The same safety levels are possible with rockets over time.
It's also because the possible margins for safety with airplanes are much higher. You can engineer redundant systems, and overbuild, because you aren't fighting the tyrrany of the rocket equation.
There is no one thing that can go wrong on a 747 that will down the aircraft. The dozen SpaceX launch/landing failures were almost all due to 'one thing went wrong, there went $60-100m USD.'
Incidentally, most other catastrophic launch failures (Including ones that claimed lives) were also due to 'one particular thing went wrong, everyone died.'
Rocket engineers aren't stupid, there's a reason that rockets don't have the amount of rendunancy and capability for failure recovery that a commercial airliner does.
C'mon, that's demonstrably false.
https://en.wikipedia.org/wiki/Turkish_Airlines_Flight_981 involved a poorly sealing latch.
https://en.wikipedia.org/wiki/Japan_Airlines_Flight_123 involved a single poorly repaired bulkhead.
https://en.wikipedia.org/wiki/TWA_Flight_800 may have been a spark in the fuel tank.
Plenty of other examples on https://en.wikipedia.org/wiki/Category:Airliner_accidents_an...
It's actually not that bad for suborbital flights. You can overbuild by a lot.
"Elon Musk’s cherry red Tesla sports car and its dummy test pilot Starman were on a new course hurtling towards the asteroid belt on Wednesday after overshooting their planned trajectory."
If Earth and Mars were in the right places then with the right payload they could have gotten to Mars itself.
Elon always said they weren't sure exactly what the final trajectory was, just that the roadster would be sent out as far as possible.
They weren't sure how much O2 would boil off during the 6-hour coast after launch before it departed orbit. That was part of the test.
Also, they weren't heading towards mars - just outwards towards mars orbit. When the roadster crosses mars orbit mars itself will not be nearby. If they wanted to actually reach mars they would have had to launch during a specific launch window when earth and mars lined up at the correct angle. This happens once every couple of years.
The energies involved are much greater, that's for sure. This will require more engineering effort.
But "never" is too strong a word. There is no good reason why we can't master this.