SpaceX (general discussion)

fredymac said:
Musk is saying Spacex will attempt a 2nd stage recovery using an inflatable hypersonic decelerator to reduce speeds re-entering the atmosphere. The stage will then be captured using one of their fairing catcher boats. He didn't clarify if the stage would use booster burns to slow down before dropping into the net or if a parachute would also be deployed. No timeline but it will be an interesting comparison with ULA to see who pursues this technology more aggressively.
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Musk on Twitter

SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon
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follow by
And then land on a bouncy house
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I guess the second stage will have inflatable heat shield for reentry
decerate to terminal velocity and land with help Airbags

Seems some one is putting NASA - IRVE program and Mars rover landing system to good use...
 
The inflatable shield was first an idea from Von Braum that suggested using as an emergency re-entry safety vehicule for "future space station" inhabitants. Then Bell (? - edit: Douglas in fact) worked something out of it.
You would have jumped out of the station, inflate a conical shape acting as heat-shield and use an axis mounted thruster to desorbit.

The main idea is to have a compact lightweight space lifeboat.

In SpaceX case, it should only be a heat-shield with the thruster used to Lower re-entry speed and the bouncy house be the net fitted boat.


EDIT:
Douglas patent (1963) with an inflatable cone for rocket re-entry: Patent nbr US3286951

Next page you'll find posted some more exhaustive source.
 
https://www.instagram.com/p/BiVG1svA9Yd/

Falcon 9 Block 5 rolling out to the launch pad
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https://twitter.com/spiel2001/status/992379866237546497?s=20

As promised, @SpaceX first #Falcon9 #Block5 on @NASAKennedy Pad 39A ahead of today's static fire test
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https://twitter.com/spiel2001/status/992384221703491584?s=20

Close-up of the upper half of the @SpaceX #Falcon9 #Block5 on @NASAKennedy Pad 39-A for today's static fire test
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https://twitter.com/spiel2001/status/992384749451796481?s=20

Close-up of the lower half of the @SpaceX #Falcon9 #Block5 on @NASAKennedy Pad 39-A for today's static fire test
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What is even more amazing is that doubling happened in a span of 8 years. SpaceX's development cycle is off the charts.
 
And the best has to come yet !

Dragon 2 test flights this year and first manned flight to ISS in December

inguration of Texas Launch site and begin launches from there

The plans to recuperate second stage of Falcon 9

and Finally BIG FALCON ROCKET program get into higher gear...

Rocket Summer is coming !
 
flanker said:
What is even more amazing is that doubling happened in a span of 8 years. SpaceX's development cycle is off the charts.
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Is it? Compare to the US space program in the 60s...

SpaceX has just rediscovered that sometimes you have to just shoot the risk management weenies and build the darned thing...
 
make no mistake, they have a top notch R&D, in particular to my knowledge in fluid flows and CFD.
 
The newest, even-more-uprated versions of Merlin 1D have a TWR of >200, which should make them the highest TWR liquid-fuelled engines in human history. SpaceX seems to be doing something right.
 
For those who not understand

TWR stands for Thrust-to-weight ratio, the engine thrust compared to the engine weight
Current used Merlin 1 has TWR of 180.1 while Raptor should have a TWR of over 300 (so far i remember right)

Fluid flows and Computational fluid dynamics are important in new rocket engines like Raptor and BE-4
like in the turbopumps the traditonal ball and roller bearings are replaced by Hydrostatic bearings, what specifically increase performance, reliability and service life.
 
I think this has been posted before, but in order to illustrate:



https://youtu.be/txk-VO1hzBY?t=5m46s
 
Michel Van said:
For those who not understand

TWR stands for Thrust-to-weight ratio, the engine thrust compared to the engine weight
Current used Merlin 1 has TWR of 180.1 while Raptor should have a TWR of over 300 (so far i remember right)

Fluid flows and Computational fluid dynamics are important in new rocket engines like Raptor and BE-4
like in the turbopumps the traditonal ball and roller bearings are replaced by Hydrostatic bearings, what specifically increase performance, reliability and service life.
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Huh. Apparently the F-1 has a higher T/W (94) than either the SSME (73) or RD-180 (78). ???
 
sferrin said:
Huh. Apparently the F-1 has a higher T/W (94) than either the SSME (73) or RD-180 (78). ???
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The SSME one is easy to explain: Denser fuels improve thrust (while making your specific impulse and thus delta-v worse), but the RD-180 just doesn't seem like a very finely optimized engine.
 
Typical I suspect people will feel of the mainstream media these days with a pretty continenous article.

Elon Musk's SpaceX Is Using Powerful Rocket Technology That NASA Says Could Put Lives at Risk

When Elon Musk and his team at SpaceX were looking to make their Falcon 9 rocket even more powerful, they came up with a creative idea — keep the propellant at super-cold temperatures to shrink its size, allowing them to pack more of it into the tanks.

But the approach comes with a major risk, according to some safety experts. At those extreme temperatures, the propellant would need to be loaded just before takeoff — while astronauts are aboard. An accident, or a spark, during this maneuver, known as "load-and-go," could set off an explosion.

The proposal has raised alarms for members of Congress and NASA safety advisers as the agency and SpaceX prepare to launch humans into orbit as early as this year. One watchdog group labeled load-and-go a "potential safety risk." A NASA advisory group warned in a letter that the method was "contrary to booster safety criteria that has been in place for over 50 years."
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https://www.sciencealert.com/elon-musk-s-spacex-is-using-powerful-rocket-technology-that-nasa-says-could-put-lives-at-risk?
 
Tuna said:
sferrin said:
Huh. Apparently the F-1 has a higher T/W (94) than either the SSME (73) or RD-180 (78). ???
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The SSME one is easy to explain: Denser fuels improve thrust (while making your specific impulse and thus delta-v worse), but the RD-180 just doesn't seem like a very finely optimized engine.
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Chamber pressure (gas generator vs. staged combustion cycle). Means beefier construction all round and more powerful turbopumps to deliver propellants against this pressure, both increasing weight. There is method to the madness though - it improves specific impulse, which affects the amount of propellants required for a given performance. Since typically a SLV consists of *a lot* more propellants than engines by weight, even a minor improvement in specific impulse may outpace a major advantage in TWR in terms of launch mass reduction.
 
Trident said:
Tuna said:
sferrin said:
Huh. Apparently the F-1 has a higher T/W (94) than either the SSME (73) or RD-180 (78). ???
Click to expand...

The SSME one is easy to explain: Denser fuels improve thrust (while making your specific impulse and thus delta-v worse), but the RD-180 just doesn't seem like a very finely optimized engine.
Click to expand...

Chamber pressure (gas generator vs. staged combustion cycle). Means beefier construction all round and more powerful turbopumps to deliver propellants against this pressure, both increasing weight. There is method to the madness though - it improves specific impulse, which affects the amount of propellants required for a given performance. Since typically a SLV consists of *a lot* more propellants than engines by weight, even a minor improvement in specific impulse may outpace a major advantage in TWR in terms of launch mass reduction.
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Tough to argue 311 for the RD-180 vs 265 SL for the F-1.
 
So the next SpaceX launch (previously scheduled for the 4th) seems to have gone into limbo. Any news? ???
 
sferrin said:
So the next SpaceX launch (previously scheduled for the 4th) seems to have gone into limbo. Any news? ???
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Talking about the Block 5 launch with Bangabandhu-1? It seems to have pushed to May 10 due to some issue encountered during the static firing on the 4th.

https://forum.nasaspaceflight.com/index.php?topic=45522.40
 
Trident said:
Chamber pressure (gas generator vs. staged combustion cycle). Means beefier construction all round and more powerful turbopumps to deliver propellants against this pressure, both increasing weight. There is method to the madness though - it improves specific impulse, which affects the amount of propellants required for a given performance. Since typically a SLV consists of *a lot* more propellants than engines by weight, even a minor improvement in specific impulse may outpace a major advantage in TWR in terms of launch mass reduction.
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Interesting to know. There's also a reason why SpaceX is chasing the highest possible TWR instead of better Isp: Since they want to do a lot of burns without payload and with almost no fuel to return the rocket, reducing dry mass can dramatically reduce the proportion of fuel they need to reserve for return. Their second stage would be much better served by a higher-isp design, though.

Anyway, it's interesting that they want to chase even higher TWR for their full staged cycle methane engine.
 
Key piece from this article about the new Falcon 9 Block 5.

That’s something NASA is happy about: the Block 5 is the rocket that SpaceX will use to launch NASA astronauts to the International Space Station, as part of the Commercial Crew Program. So this version has been built to meet all of the space agency’s rigorous safety standards. NASA is requiring that SpaceX fly the Block 5 at least seven times successfully, without any major changes, in order to certify it for human flight. It’s a stringent requirement, especially for a rocket that’s flown numerous times before. In comparison, NASA’s future Space Launch System will only do one test flight before it’s certified to fly humans. And the Space Shuttle’s very first flight had humans on board. “SpaceX is going through a level of rigor and improvement that far exceeds everything that’s been done in human spaceflight,” says Autry.
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https://www.theverge.com/platform/amp/2018/5/9/17254384/spacex-falcon-9-block-5-upgrade-rocket-reusability-savings
 
The seven-flights-requirment was set and suggested by SpaceX - not NASA.
 
This may be helpful with understanding certification requirements. There may be something newer.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160002252.pdf

"
• Vehicles on contract but not certified must propose a credible certification path as part of their bid, cannot bid until after a first successful flight

"
 

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Webcast of the Bangabandhu-1 launch and first stage return:

https://www.youtube.com/watch?v=rQEqKZ7CJlk

Tuna said:
The newest, even-more-uprated versions of Merlin 1D have a TWR of >200, which should make them the highest TWR liquid-fuelled engines in human history. SpaceX seems to be doing something right.
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I was wrong about that. They are now flat rating their engines for 190 000lbf of thrust, for a TWR of 184, from sea level to space. The performance at sea level was improved substantially, but the vacuum performance only got ~5000lbf extra. They appear now to be limited by their chamber strength.
 
sferrin said:
I was waiting for the 1st stage camera to fall off.
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It looked like it was getting flooded with condensation.
 
Here's everything Elon Musk told reporters about the reusable rocket that will fly twice within 24 hours

https://www.cnbc.com/2018/05/11/full-elon-musk-transcript-about-spacex-falcon-9-block-5.html
 
Flyaway said:
Here's everything Elon Musk told reporters about the reusable rocket that will fly twice within 24 hours

https://www.cnbc.com/2018/05/11/full-elon-musk-transcript-about-spacex-falcon-9-block-5.html
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Some highlights from the transcript:

The key to Block 5 is that it's designed to do 10 or more flights with no refurbishment between each flight – or at least not scheduled refurbishment between each flight.

We believe that the Block 5 boosters are capable of on the order of at least 100 flights before being retired.

Our goal, just to give you a sense of how reusable we think the design can be, we intend to demonstrate two orbital launches of the same Block 5 vehicle within 24 hours, no later than next year.

You’ve got the boost stage is probably close to 60 percent of the cost, the upper stage is about 20 percent of the cost, fairing is about 10 percent and then about 10 percent which is associated with the launch itself. So if we're able to reuse all elements of the rocket, first of all, it'd be the first ever fully-reused orbital vehicle of any kind. And then we'd be able to reduce the cost for launch by an order of magnitude.

We may be able to get down to a marginal cost for a Falcon 9 launch down, fully considered, down under $5 million or $6 million.
 
FighterJock said:
The next Iridium NEXT/ GRACE-FO mission will soon be launched as SpaceX has just conducted a static test fire of the Falcon 9 rocket engines, the rocket will launch on Tuesday if there is no delays due to the weather.

https://www.nasaspaceflight.com/2018/05/spacex-falcon-9-static-fire-iridium-next-6-grace-fo/

I almost forgot to add, that the core stage of the Falcon 9 rocket is the same stage that launched the classified ZUMA mission back in January.
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I thought from here out all were going to be Block 5? ???
 
sferrin said:
FighterJock said:
The next Iridium NEXT/ GRACE-FO mission will soon be launched as SpaceX has just conducted a static test fire of the Falcon 9 rocket engines, the rocket will launch on Tuesday if there is no delays due to the weather.

https://www.nasaspaceflight.com/2018/05/spacex-falcon-9-static-fire-iridium-next-6-grace-fo/

I almost forgot to add, that the core stage of the Falcon 9 rocket is the same stage that launched the classified ZUMA mission back in January.
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I thought from here out all were going to be Block 5? ???
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I will probably need to find out if that is the case, but for now I think that could be the last of the old core stages getting used until they get the new Block 5 in production.
 
sferrin said:
FighterJock said:
The next Iridium NEXT/ GRACE-FO mission will soon be launched as SpaceX has just conducted a static test fire of the Falcon 9 rocket engines, the rocket will launch on Tuesday if there is no delays due to the weather.

https://www.nasaspaceflight.com/2018/05/spacex-falcon-9-static-fire-iridium-next-6-grace-fo/

I almost forgot to add, that the core stage of the Falcon 9 rocket is the same stage that launched the classified ZUMA mission back in January.
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I thought from here out all were going to be Block 5? ???
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They still have several older block Falcon 9s with at least one more reflight in them. IIRC they're only going to refly them once each, as well as use them in expendable missions so that they can both gather additional data, reduce costs for them and their customer, provide a buffer until Block 5 supply can meet demand and simultaneously clear out the old inventory.
 
Dragon029 said:
sferrin said:
FighterJock said:
The next Iridium NEXT/ GRACE-FO mission will soon be launched as SpaceX has just conducted a static test fire of the Falcon 9 rocket engines, the rocket will launch on Tuesday if there is no delays due to the weather.

https://www.nasaspaceflight.com/2018/05/spacex-falcon-9-static-fire-iridium-next-6-grace-fo/

I almost forgot to add, that the core stage of the Falcon 9 rocket is the same stage that launched the classified ZUMA mission back in January.
Click to expand...

I thought from here out all were going to be Block 5? ???
Click to expand...

They still have several older block Falcon 9s with at least one more reflight in them. IIRC they're only going to refly them once each, as well as use them in expendable missions so that they can both gather additional data, reduce costs for them and their customer, provide a buffer until Block 5 supply can meet demand and simultaneously clear out the old inventory.
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Thanks for the added information Dragon029. One further question though, was the Falcon 9 Block 5 launch back in May a test launch?
 
FighterJock said:
Thanks for the added information Dragon029. One further question though, was the Falcon 9 Block 5 launch back in May a test launch?
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It was a test in that it was the first flight with all the Block 5 hardware and they gathered information for future flights, as they do in every launch. However, it wasn't a pure experimental flight like Falcon Heavy. It did carry a paying commercial payload -- Bangladesh's first communications satellite.
 
TomS said:
FighterJock said:
Thanks for the added information Dragon029. One further question though, was the Falcon 9 Block 5 launch back in May a test launch?
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It was a test in that it was the first fligth with all the Block 5 hardware and they gathered information vfor future flights, as they do in every launch. However, it wasn't a pure experimenta flight like Falcon Heavy. It did carry a paying commercial payload -- Bangladesh's first communications satellite.
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Thanks TomS, I sort of had known that it was not an experimental flight like the Falcon Heavy.
 

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