SpaceX launches four astronauts to ISS
Using its Falcon 9 rocket lifting off from Cape Canaveral, SpaceX early this morning put four astronauts into orbit for a six month mission to ISS.
The Dragon capsule, Endurance, was making its third flight. The first stage, flying for the first time, landed successfully back at Cape Canaveral.
The leaders in the 2023 launch race:
58 SpaceX
37 China
12 Russia
7 Rocket Lab
In the national rankings, American private enterprise now leads China in successful launches 67 to 37. It also leads the entire world combined, 67 to 60, while SpaceX by itself now trails the rest of the world (excluding American companies) 58 to 60 in successful launches.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Using its Falcon 9 rocket lifting off from Cape Canaveral, SpaceX early this morning put four astronauts into orbit for a six month mission to ISS.
The Dragon capsule, Endurance, was making its third flight. The first stage, flying for the first time, landed successfully back at Cape Canaveral.
The leaders in the 2023 launch race:
58 SpaceX
37 China
12 Russia
7 Rocket Lab
In the national rankings, American private enterprise now leads China in successful launches 67 to 37. It also leads the entire world combined, 67 to 60, while SpaceX by itself now trails the rest of the world (excluding American companies) 58 to 60 in successful launches.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
I noticed slightly less emphasis on covering the landing of the first stage this time. Of course the main event is as it should be the payload, especially when it is people!
Another thing I noticed was the last-minute (literally) “resolution” of a sensor reading of minute traces of a hypergolic thruster gas in the capsule. The resolution seemed to be “It’s too little to worry about.”
At the risk of being an armchair quarterback, isn’t ANY reading of such dangerous stuff enough to worry about? I sure don’t want to see the advent of “Challenger go-fever” in this program!
I also noticed that the entry burn was extremely short, and the plasma (?) trails left by the subsequent atmospheric entry seemed unusually vivid, as if the entry speed was higher than normal. This could not be verified since there was no displayed data for the booster displayed (see previous comment). This was the first flight for this booster.
Guess: SpaceX used the occasion on a new booster to establish a maximum-speed entry profile. This might help them understand how much they could increase payload (by using less retro fuel) without impacting booster reusability too seriously.
As the number of reuses of some boosters is getting nearer to 20, someone may be saying “Let’s make sure we don’t end up with a glut of high-time boosters, and have to throw them away to keep the fleet fresh, when we could maybe push them harder and get more payload!”
“America’s broomstick” does it again!
Space X launched 42 people into orbit in just over 3 years.
I read China has launched 12.
Don’t know how many Russia has launched since May 2020.
Ray Van Dune: While testing during operational procedures makes sense and is SpaceX’s normal approach, it seems a mistake to push the envelope on a new booster, when you’ve got some old ones that you will need to retire soon anyway. Why not use the old boosters to test maximum speed reentry instead of a new one? If you lose one you have at least gotten 15+ flights from it.
Having said that, you raise interesting questions about this flight.
Bob, that’s a fair question, but I think the answer is that it is much more straightforward and more accurate to take a new booster as your baseline, especially since it will incorporate all the latest design features that could promote higher sustainability. Measuring the wear and tear on an old booster might just give you an old answer for old boosters, when what you really want is a current answer for your current boosters!
This is sort of a derivation of the sunk-costs fallacy, a fallacy for which I suspect Elon Musk has developed an exceptionally strong immunity!
Ray Van Dune: You make an excellent point. I suspect a combination of both approaches using operational boosters (or any equipment) new and old, is likely the smartest approach.
I want solicit comments on all the chatter regarding the Crew-7 4 second entry burn controversy.
Look at AS-2 telemetry and typical a SL telemetry. The booster Crew-7 telemetry was not shared by NASA but we can infer it from AS-2 or just about any RTLS mission. To wit, SL barge landing boosters reaches about 8000 +- kph. The entry burn scrubs off 2kph and is traveling about 6000 kph at shutdown.
RTLS top speed at MECO is 6270 kph. After boost back and falling for a few minutes the top speed is 4600 kph at entry burn initiation and 4400 kph after shutdown.
So a typical SL booster is traveling 1400 kph faster at the end of the entry burn than a RTLS booster at the start of its burn.
It makes one wonder why even bother with an entry burn at all for a RTLS mission unless it is safer to burn off extra propellant with an entry burn to presumably get the booster mass right for a standard landing burn that begins about 860-1000 kph and 1.2-1.4kog for all missions.
Mark,
Just an off-the-top-of-my-head thought: the difference in speeds may have something to do with the angle that the booster has during descent. If it enters at a more shallow angle, then it may have more time in the thinner atmosphere to slow down before it reaches the thicker part of the atmosphere. This would allow it to be traveling somewhat faster at engine shutdown than if the reentry angle were steeper.
New Shepard does not have this advantage. It goes straight up and straight back down, so its entry back into the thicker atmosphere is less varied, more consistent, and always steep.
Ed,
Thanks for the comment and I agree that the RTLS boosters travel a lot slower than the faster trajectories. My real questions is why bother w/ the entry burn at all since the booster is already going slower (4,500 kph) than a booster after a normal entry burn that is performed to shield the bottom of the booster from the plasma generated during reentry from 8,000 kph to around 6,000 kph. If is is just a mass reduction burn instead of a heat shield burn, why not just extend the boost back burn to get the mass right and eliminate all entry burns for RTLS missions? Sx might be able to reduce the amount of TEA-TEB needed going from 3 to 2 inflight burns and obtain some additional performance.
Mark,
It could be that it is slower but deeper in the atmosphere, where the forces and stresses may be greater. If they are doing a mass reduction burn, then they must think that the booster will not slow down quickly enough to ensure no damage occurs on the way down, which brings me back to the first sentence. I doubt that they would do it just for mass reduction, because they would be able to use the fuel on landing.
Extending the boost back burn would change the performance in different ways. Either the booster would be traveling too fast horizontally and risk missing the landing pad and falling inland (possibly in a populated area, but I don’t remember much of that from the last time I was there, three decades ago) and making a reentry burn even more necessary, or the booster would have a higher apogee and would travel even faster as it reached the denser part of the atmosphere, again making a reentry burn even more necessary.
Reducing the amount of hypergolic is an admirable goal. It makes the booster safer when it returns and mildly safer before launch (although I don’t think anyone would consider one canister (I don’t think that is the work SpaceX uses) pair less as being safer enough to mention — plus it would be the best part, meaning Musk’s “no part”). There is a small cost savings, too, and it reduces the complexity of the operation.
Additional performance was not needed on this launch. We can tell, because when SpaceX needs the extra performance, they land their boosters on their autonomous drone ships (don’t you miss the easier to type “barge”?)
A lot of thought goes into trajectory planning. They are unlikely to have the booster do more than necessary. However, there are also contingencies to consider, and they may have added in extra propellants for the “just in case” case, and then had to plan for its added weight and what to do should everything work as expected rather than needing the contingency mass. Airliners carry more fuel than they need to reach their destinations as a contingency; the Falcons would have to, too. Remember the time that one of the early test boosters ran out of fuel just a few feet above the barge? Not enough contingency propellants; they cut it too close.