Exoscientist

Is that an accurate representation of how the separation was supposed to work? Bob Clark

There seems to be universal agreement that not having flame diverters was a mistake. As the “Angry Astronaut” puts it, the launch should be considered a success but major improvements need to be made,

By separation mechanism I mean one of the methods used before on staged rockets that mechanically separates the stages, not simply using centrifugal force. Robert Clark

What they’re discussing at SpaceX right now, “Ok, whose bright idea was it not to have a stage separation mechanism?” This article discusses the decision not to have a stage separation mechanism: https://www.teslarati.com/spacex-starship-new-simplicity-extremes/ An unfortunate decision because if the stages did separate there might not have been any need to send the destruct signal. Plus you would have gotten far more data by seeing what the Starship upper stage could do. Bob Clark

Think that’s an April Fools joke. Bob Clark

Avi Loeb has received a $1.5 million private grant to conduct his search for the interstellar meteorite fragments beneath the ocean’s surface: https://avi-loeb.medium.com/a-gift-from-a-silver-star-af2993e0169a Bob Clark

I agree with you number of launches is the more important parameter. Likely prices will decrease and as you said if it decreases by half, that means 2,000 Falcon 9 equivalent launches. But that means an even larger market for other launch companies to get into and even greater necessity for them to get into reusables. Robert Clark

Global Space Launch Services Market is projected to reach at a market value of US$ 47.6 Billion by 2030: Visiongain Research Inc October 05, 2021 09:33 ET | Source: Visiongain Ltd https://www.globenewswire.com/news-release/2021/10/05/2308874/0/en/Global-Space-Launch-Services-Market-is-projected-to-reach-at-a-market-value-of-US-47-6-Billion-by-2030-Visiongain-Research-Inc.html Several independent market research surveys have put the space launch market at about the ~$40 billion range by ~2030. That amounts to about 1,000 reusable Falcon 9’s. That’s a large market for other launch companies to also take part in. BUT they have to use reusables to stay competitive with SpaceX. Otherwise, they’ll also go the way of ULA having to ask for buyers to avoid bankruptcy. In that regard ULA and Arianspace should upgrade their coming launchers, Vulcan Centaur for ULA and Ariane 6 for Arianespace, to add an additional engine to their first stages. As it is now, neither can lift off without using solid side boosters. But the space shuttle showed solid side boosters do not save costs on reuse, while SpaceX showed all-liquid rockets do. Robert Clark

I had estimated that the Vulcan Centaur given three BE-4's could get ~27 tons to LEO. But that was using a weight-optimized Vulcan dry mass estimate. However, I tried the SilverbirdAstronautics.com estimator on the Vulcan with the usual two BE-4's in the two side booster configuration and it gave results well above what was given on the ULA page on the Vulcan Centaur. So I think my dry mass estimate was too optimistic, i.e., too low. What I used was 25,000 kg for the Vulcan booster dry mass given three engines. The basis for that estimate is the weight-optimized Falcon 9 booster, using aluminum-lithium for the tanks, gets about a ~25 to 1 mass ratio. Then since methalox is at about 80% density of kerolox it should get about 20 to 1 mass ratio. This would give the Vulcan booster a dry mass of 25,000 kg. But that dry mass results in a badly overestimated V/C with two side boosters payload compared to that stated by ULA. So here's a another stab at a dry mass estimate. Make a comparison to the Atlas V booster mass ratio. This is hardly weight-optimized using just standard aluminum for the tanks as does the Vulcan stage. The Atlas V booster has a mass ratio of only 15 to 1. Then the Vulcan with methalox at only 80% the density of keralox might get ~12 to 1 mass ratio. So the Vulcan dry mass might be as high as 45,000 kg. This results in a much closer Silverbirdastronautics.com payload estimate to the ULA numbers. Bob Clark

Not like I know him. I asked via his twitter account: Bob Clark

“PD”? I use the numbers provided by the companies when provided. But some key numbers often are not provided such as stage dry masses, and often propellant masses. I asked Tory Bruno once about this and he said it was for competitive advantage. Bob Clark

Not lying. Just puzzling. Why not just give give it 3 BE-4’s so can launch fully loaded without side boosters? With side boosters you then get even higher payload. I used the payload estimator of Silverbirdastronautics.com to estimate a LEO payload of ~27 tons using 3 engines on the first stage w/o side boosters. This would beat the ~22 ton payload of the Falcon 9. BTW, it could then also do SSTO without the Centaur V upper stage. ;-) Robert Clark

Can Vulcan Centaur launch on just two BE-4 engines without side boosters? This Blue Origin page says Vulcan Centaur can get 10.8 tons payload to LEO on its two BE-4 engines without using side boosters: But we can calculate the mass of the Vulcan booster to show its beyond that of the thrust of the two BE-4 engines. See here: According to the heights given along the side of the image on the right, the bottom of the booster tank is at about 20 feet high, and its top at about 110 feet, for a length of 90 feet, 27.4 meters. The diameter is 5.4 meters, for a radius of 2.7 meters. Then the volume is π*2.72*27.4 = 627.5 m3 . The density of methalox or methanolox at the mixture ratio of liquid O2 to CH4 of 3.6 is about 800 kg/m3. Then the mass of the propellant is 502,000 kg. But the sea level thrust of the BE-4 engine is 550,000 pounds, so two is 1,100,000 pounds, i.e., 500 metric tons force. So two BE-4’s could not even loft the booster stage, let alone the upper stage and payload. Robert Clark

Yes. I copied this from another site with a different font. I’ll correct it. Robert Clark

Thanks. I took this image for the February Superheavy static test to be size of the exclusion zone for an actual launch: This is only an area 3 minutes, 15 seconds of latitude wide, that's 3.7 miles, 6 km. But this means the radius from the launch site is 2 miles, 3 km. But here is the image from the FAA report: https://www.faa.gov/space/stakeholder_engagement/spacex_starship/media/Draft_PEA_for_SpaceX_Starship_Super_Heavy_at_Boca_Chica.pdf This shows the exclusion radius for the public about 4 miles, 6.4 km. Perhaps the smaller map shown in the "Marine Safety Information Bulletin" was only for the SuperHeavy static test in February. I understand that only had 1/3rd propellant load. The larger area shown in the FAA map might be sufficient for the public. Still, one should be wary of the amount of damage even kilometers away as demonstrated by the Halifax and Texas City disasters, both in the ~3 kiloton range: https://en.wikipedia.org/wiki/Halifax_Explosion#Explosion https://sometimes-interesting.com/texas-city-disaster-deadliest-industrial-accident-in-u-s-history/

One responder to that twitter thread claimed he heard that booster is to be scrapped. Robert Clark

Updated discussion of the topic: SuperHeavy+Starship have the thermal energy of the Hiroshima bomb. UPDATED, 3/8/2023. https://exoscientist.blogspot.com/2023/03/superheavystarship-have-thermal-energy.html Key points: 1.)While the explosive force of the SuperHeavy/Starship (SH/ST) is not likely to reach that of its full thermal content of 13.3 kilotons of TNT, comparable to the Hiroshima bomb, it is still likely to be in the range of 3 to 5 kilotons of TNT. 2.)The Halifax and Texas City disasters of comparable explosive force suggests damage can extend kilometers away. 3.)The hazard or exclusion zones of only 2 miles, 3 km, for SH/ST is likely inadequate based on the Halifax and Texas City disasters. 4.)SpaceX ignored FAA warnings not to launch SN8 due to weather conditions exacerbating the effects of a possible blast wave from an explosion. 5.)The Starship SN11 explosion in midair may have been a BLEVE, which introduces an additional detonation mode for cryogenic fuels. 6.)At least one Raptor leaked methane and caught fire on multiple test flights of the Starship. 7.)Since the SuperHeavy static test lasted little more than 5 seconds, a strong possibility exists that multiple engines will fail during a full burn of an actual flight. Recommendations. 1.)It should be revealed to the public the SH/ST has the thermal energy content of the Hiroshima bomb. 2.)Experts on launch vehicle explosions and fuel-air detonations should present a report to the public explaining what the likely explosive force would be if the vehicle exploded. 3.)SpaceX should not be granted a launch license for the SH/ST until SpaceX constructs a separate engine test stand sufficient to test all 33 Superheavy engines at the same time time, at full power, and at full flight duration, and for such tests to complete successfully for multiple tests.

There is speculation on the new Starship nosecone: SInce ship 26 will be expendable maybe the new nose cone is without header tanks in the nose. Robert Clark

The difference is speed. It took 10 yeas for New Horizons to each Pluto. The high Isp of the ion engines would allow them to get to one of the outer planets or dwarf planets more quickly. The high Isp also means they could slow down to actually go into obit. Bob Clark

And let’s not forget: Anyone ever do a Kerbal sim to the outer planets of such a mission? Robert Clark

I only saw these calculation for the two stage. Robert Clark

Try the Silverbird calculator for the SSTO payload. Note that for an actual SSTO, you won’t use the full nose cone/payload section of the full two-stage . Estimate the SSTO payload with a fairing 1/10th the size of the current one. Robert Clark What’s the scuttlebutt on the NasaSpaceflight.com forum for the purpose of Ship 26? I’m persona non grata on that site for my SSTO speculations. Robert Clark

Thanks for that. I didn’t know you could do static fires there, which would need hold down clamps for example. I’ll be interested to find out if they’ll be installing 6 engines on it, as that is the current plan for an operational Starship. If yes, then it can do a launch fully fueled. Robert Clark

Interesting article: Much web discussion is going on on space forums about the Starship version Ship 26. This surprised everyone in being a completely expendable format. It has no top or bottom flaps, heat shield, or legs. Since it is to be expendable it likely also has no ballast tanks. The most frequent speculation is its a test vehicle for orbital refueling. But it has no visible external connections for linking up to another Starship. The key clue is it’s moved to the suborbital launch pad. This means it can launch without the SuperHeavy booster. With 6 Raptor 2 engines it can launch fully fueled unlike the previous Starship test flights meant just to test landing. The key question: what is the dry mass of this expendable version without flaps, legs, heat shield, or ballast tanks? If you know that you can calculate how much payload it can lift to orbit in a single stage. Elon said the expendable version with only 3 engines might mass only 40 tons: https://twitter.com/elonmusk/status/1111798912141017089?s=61&t=A46qVnS2GH4VVA-pQSUlkg Add another 5 tons for 3 more engines and this version might mass 45 tons. However, the increased thrust may require strengthening of the tanks which would increase the dry mass. On the other hand, this version would have to support far less payload atop it than the max 250 tons of the full two-stage so would need reduced tank strengthening. The argument can be made that just being moved to the suborbital launch pad does not mean it is going to be launched. It might be just used for pressure testing for example. However, the “Angry Astronaut” did a video from Boca Chica showing the Raptor work station being moved towards Ship 26: https://www.youtube.com/live/MmUwHVji9b4 He says that’s only done if you are installing engines on the Starship. You don’t do that if you are only doing pressure testing. He notes though that it could be putting engines either on S26 or S25. Probably we’ll know by the end of today which ship is having engines installed. Robert Clark

The Europa Clipper mission will be an orbiter mission to Europa to be launched on the Falcon Heavy in the 2024 time frame. But an actual lander mission to Europa could also be lauched in the same time frame on a Falcon Heavy. Having both orbiter and lander missions at the same time would be as revolutionary for planetary space science as were the Viking missions to Mars. Can we adapt the Antarctica IceCube Neutrino Observatory drilling technique to explore the subice oceans of Europa? https://exoscientist.blogspot.com/2023/01/can-we-adapt-antarctica-icecube.html Bob Clark