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#2326 2026-06-17 16:13:23
- Void
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Re: Starship is Go...
OK, back onto the main path then. I think they are still sub-orbital to make sure that it comes down in the ocean if they lose control.
I believe that G. Shotwell has indicated hopes that orbital and actual may occur 6-12 months. Never certain, but possible.
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#2327 2026-06-18 09:29:27
- GW Johnson
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Re: Starship is Go...
The flight test orbit SpaceX has been using is "suborbital" but just barely! It essentially tests for entry at full orbital-class speeds. It is an ellipse with an apogee at something near 200 km altitude, when something above 300 km is needed to avoid rapid decay. This is well outside the entry interface altitude of 140 km.
The perigee of that flight test ellipse is down in the atmosphere at something between the surface and the entry interface altitude of 140 km. That is what makes it "suborbital": atmospheric entry is inevitable, as you approach the perigee down in the atmosphere.
The suborbital trajectories of intercontinental ballistic missiles are also ellipses with exo-atmospheric apogees, but usually subsurface perigees, because of the limited ranges between launch site and target. In 2-D Cartesian coordinates that kind of thing looks and analyzes like a parabolic trajectory, right out of high school physics.
Any of you can analyze such elliptical orbits for yourselves, with my orbits spreadsheet that supports the orbits+ course. You can access that from the "orbital mechanics class traditional" thread in the "interplanetary transportation" topic. It's a free download. The links to the online drop box are in that thread. All it does is provide an organized and automatic way of evaluating the classic textbook equations for a 2-body orbital mechanics problem, limited to the elliptical case (escape parabolas and escape hyperbolas not included).
GW
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#2328 2026-06-18 09:42:40
- GW Johnson
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Re: Starship is Go...
SpaceX has a legal obligation from the FAA to investigate why the engines on the Superheavy booster failed, so that it could not fly its intended trajectory after staging. They have an internal technical obligation to do that, anyway.
There may, or may not, be a connection between the hot staging that "did not look right", and the booster engine failures, and maybe even the 1 engine lost on the Starship upper stage. SpaceX has an internal technical obligation to investigate all of those things.
Meanwhile, it looks like they finally got their heat shield "right", at least for 8 km/s-class LEO entries. Near-escape is another class of problem entirely, as regards heat shielding.
They will need to time to investigate these things and decide what changes to make. Then expect to see the same basic test flight flown again, hopefully to include both booster flyback and landing, plus a Raptor restart demo in space. I wouldn't think they would also include a tower grab of the booster, but they could. Depends upon how confident they are in their booster fix, because a near one-of-kind catch tower is at risk.
GW
Last edited by GW Johnson (2026-06-18 09:43:32)
GW Johnson
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#2329 2026-07-17 09:22:26
- GW Johnson
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Re: Starship is Go...
I see that SpaceX attempted unsuccessfully to launch its Version 3 Starship/Superheavy yesterday. It suffered an automatic abort just as the engines were beginning to ignite. Nobody knows why yet, near as I can tell. But at least the automatic sequencing worked properly to include an abort shutdown, and well enough not to destroy the vehicle and launch facility in an explosion.
You have to remember, Version 3 is NOT version 2! This is a new bird! With new engines! It had a partial success on its first test flight (Flight 12). Flights 1-11 are related experience, not tests of this configuration!
GW
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#2330 2026-07-18 06:22:55
- tahanson43206
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Re: Starship is Go...
This is a follow up to Post #2329 by GW Johnson ....
WASHINGTON, July 16 (Reuters) - SpaceX's (SPCX.O), opens new tab Starship rocket triggered a last-second abort before liftoff for its 13th flight test from Texas on Thursday as some of its 33 engines failed to start, with CEO Elon Musk saying it will likely try to launch again early next week.
Shares of SpaceX, which went public last month, fell about 3% in aftermarket trading following the scrubbed launch. The stock ended at $131.11 on Thursday, closing below its IPO price of $135 for the first time since listing.Item 1 of 5 The SpaceX Starship and Super Heavy v3 Booster stand at pad 2 at sunrise before its 13th test flight from the SpaceX launch complex in Starbase, Texas, U.S., July 16, 2026. REUTERS/Steve Nesius TPX IMAGES OF THE DAY
[1/5]The SpaceX Starship and Super Heavy v3 Booster stand at pad 2 at sunrise before its 13th test flight from the SpaceX launch complex in Starbase, Texas, U.S., July 16, 2026. REUTERS/Steve Nesius TPX IMAGES OF THE DAY Purchase Licensing Rights, opens new tab
"Some of the engines didn't start, triggering an automatic launch abort," Musk said in a post on X, without disclosing the number of engines on the Super Heavy rocket that did not start. "To be confident of a good flight, 2 Raptors will be removed & replaced. Most probable launch timing is early next week."
The launch abort came less than a second before Starship's planned liftoff from Starbase, SpaceX's company town in south Texas, at 5:45 p.m. CT (2245 GMT). The rocket's engines ignited but cut off shortly after.
"We did trigger a hold on the booster that aborted our liftoff as we were starting to light those Raptor engines," said SpaceX spokesperson Dan Huot, speaking on the company's live stream after the launch was scrubbed.
Reporting by Joey Roulette and Chris Thomas; Editing by Chris Reese and Jamie Freed
Sounds to me like a fairly routine automatic shutdown with successful safing procedure. SpaceX will encounter more of these in coming years, as engines age with repeated use.
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#2331 2026-07-23 15:46:53
Re: Starship is Go...
I watched the Nasaspaceflight broadcast of what was supposed to be a static fire. It didn’t occur. There was then discussion among the hosts of what exactly happened since there was no flame produced. At first they thought perhaps it was just a spin prime test. But it was just too little gas produced underneath the rocket to be a full spin prime so maybe even that had to be curtailed.
SpaceX is now in a difficult position. They know from the prior try at a static fire back in March that had to be rapidly aborted that this damages the engines:
https://x.com/grok/status/2080393370753528136?s=61
It is likely last week’s rapid abort of a launch attempt also damaged engines. But was it really only two engines being replaced in this case as Elon first said? The difficult position they are in is it would be time consuming and detrimental to the public view of the Raptor reliability if all engines had to be replaced, and especially in the stock markets view.
But then now even a spin prime test was not successfully completed. Despite what SpaceX portrays to the public, they know the Raptor is not reliable under multiple starts. So they don’t even want to risk another static test.
Then, this is now going to be the riskiest launch attempt since the very first test launch of the Starship.
Bob Clark
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“Anything worth doing is worth doing for a billion dollars.”
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#2332 2026-07-23 15:56:30
- GW Johnson
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Re: Starship is Go...
Musk is playing this closer to the chest than before. I guess the fall in stock prices has him worried, but he is reacting badly, if that is an issue at all. I saw no news reports indicating that they wanted to launch Flight 13 today, until I saw one lone report that the attempt was canceled because of bad weather induced by Tropical Storm Bertha.
I did see one report indicating they think they figured out what went wrong with the Flight 12 hot staging being 90 degrees out of the intended plane. It had to do with the startup sequence they used for Starship's engines for hot staging. I infer that means the order in which engines are ignited. Supposedly they have "corrected" this for Flight 13. How being off 90 degrees for the flip killed so many engines on the Superheavy was entirely unaddressed in the one report that I saw. But I suspect the Superheavy propellants became unsettled by an abnormal flip, and the engines sucked vapor instead of liquids. That does make turbopumps explode!
I also saw one report that they may try again to launch 13 tomorrow. But I distrust the few reports from secondary sources. There was NOTHING about any of this on SpaceX's website.
GW
Last edited by GW Johnson (2026-07-23 15:58:07)
GW Johnson
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#2333 2026-07-24 18:10:12
- GW Johnson
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Re: Starship is Go...
Just finished watching "Lucky 13" live on the SpaceX website. Launch good. Hot stage good. 6 engines on Starship, booster did its flip and boost-back OK. Booster lit engines hanging on grid fins at entry, but lost a couple of them during the landing burn, and hit "hard" in the water. Upper stage Starship ascent OK. Deploy 20 v.3 Starlinks OK. Relight 1 SL Raptor in space with 14 s burn OK. Entry looked good. Descent looked good, including maneuvers. 3 SL Raptors lit and executed flip, then final descent as planned on 3, then 2, then 1 engine, to a very gentle splashdown. Vehicle fell over onto its dorsal side, but did not explode. Venting methane burned, but no explosions. Fantastic photography of heat shield, as it floated nice and high in the water on its back. Except for booster splashdown, test flight looked to be just about perfect!
Here is an image created by GW Johnson to illustrate the text above:
(th) 2026/07/25
GW
Last edited by GW Johnson (2026-07-24 18:13:11)
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#2334 2026-07-25 15:17:56
- tahanson43206
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Re: Starship is Go...
The article at the link below covers a number of aspects of the recent Flight 13 of Starship in some detail.
https://arstechnica.com/space/2026/07/s … wtab-en-us
The article includes a prediction that SpaceX will try to tow the still floating Starship to Australia for inspection of the heat shield system.
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#2335 2026-07-26 08:46:32
- Void
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Re: Starship is Go...
I have been evaluating or trying to estimate relative risk of Starship being directed to the Gulf or even a tower catch.
Because most of the propellants have been expended, and because it is only 1 of 2 stages, it is considerably safer than to have a pad explosion like Blue Oiigin did.
Looking at things online, it appears that Starship has about 60% of the dry mass that Super Heavy does. So, I presume that reserve propellants for landing will be about 60% that of Super Heavy.
An explosion would be about as bad as the ones we usually see when they land in the Indian Ocean. Not wonderful but not catastrophic.
That they were able to dump the ship into the ocean mostly in one piece, can be important, as it may in the future be needed to do that on a bad day to protect human crew if there are any.
If they can do what they did on 13 and tow the ship into a port or on land, then the ability to examine the ship in detail would be very valuable, I am sure.
But if they could catch it on a tower, it might be that the risk is only 60% of the risk of catching a Super Heavy, as the dry mass and presumed remaining propellants will be about 60% dry mass and only maybe 30 tons remaining propellants.
Actually, maybe the numbers are better than I supposed. Query: "What are the dry masses of Superheavy and Starship?"
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Dry Masses of Super Heavy and Starship
Super Heavy dry mass: about 275,000 kg (606,000 lb) Wikipedia+1
Starship dry mass (Block 1): about 100,000 kg (220,000 lb) Wikipedia
Starship dry mass (Block 2): about 85,000 kg (187,000 lb) WikipediaDetails
Super Heavy is the first stage booster of the Starship system, powered by 33 Raptor engines. Its empty (dry) mass is roughly 275 metric tons, with a gross launch mass of about 3,675 metric tons and propellant mass of ~3,400 metric tons Wikipedia+1.Starship is the second stage spacecraft. In Block 1, its dry mass is ~100 t; in Block 2, it is ~85 t Wikipedia. These figures exclude propellant, which is the main contributor to the vehicle’s total mass.
Both stages are made of stainless steel and are designed to be fully reusable, with the Super Heavy returning to the launch site and the Starship landing on a drone ship or land Wikipedia.
If you need the combined dry mass of the full Starship system (Super Heavy + Starship), it would be roughly 360–380 metric tons depending on the block version.
Quote: "How much propellant does Starship need to land on Earth?"
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Propellant Needed for Starship to Land on Earth
For a Starship mission to land on Earth, the propellant requirement depends on the vehicle’s mass, velocity, and the amount of delta‑v needed to decelerate from orbital or reentry speeds to zero at touchdown.Delta‑v for landing
To land vertically on Earth, Starship must provide enough thrust to cancel its vertical velocity. For a typical Earth‑orbiting Starship (around 100ton payload, ~120ton gross mass), the required landing delta‑v is about 100m/s Reddit. This is much less than the ~10km/s needed to escape Earth’s gravity, but it’s still a significant portion of the vehicle’s total velocity.Propellant mass for landing
Using the rocket equation and typical Raptor engine performance (CH₄/LOX, ~327s specific impulse in sea level), the propellant needed to provide 100m/s of delta‑v is roughly 6tonnes of propellant for a 100ton payload mission Reddit. This is a small fraction of the total propellant used for launch (which is ~4,600tonnes for a 100ton payload to LEO) hub.sivo.it.com.Why so little?
The vehicle is already moving at high speed when it begins its descent.
Aerodynamic drag and gravity alone can decelerate it significantly before engine burn‑out.
The landing burn is short and focused on the final vertical velocity.
Comparison to other bodies
For Mars, the landing delta‑v is higher (~480m/s) due to lower gravity and thinner atmosphere, requiring about 30tonnes of propellant for the same payload Reddit.Summary table
Mission type Delta‑v (m/s) Propellant needed (tonnes)
NotesEarth landing ~100 ~6
Short burn, high atmospheric dragMars landing ~480 ~30
Lower gravity, thinner atmosphereIn short: Starship needs only about 6 tonnes of propellant to land on Earth, compared to ~30 tonnes for Mars, because Earth’s atmosphere and gravity provide much more deceleration before the engines engage Reddit.
And if the landing burn has initiated, some of that propellent will have been burned off prior to either contacting the ocean or the catch tower.
So relative to launch risk landing risk is rather low, and for Starship perhaps lower than for Superheavy.
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Last edited by Void (2026-07-26 09:02:58)
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#2336 2026-07-26 11:32:10
- GW Johnson
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Re: Starship is Go...
1. The fires and explosions seen with Starship toppling over into the sea after splashdown are mostly methane burning with air, suddenly aggravated by exposure of that fire to LOX, creating the violent explosions. Until Flight 13, all such Starships broke open upon toppling over, and the ignition source for methane-air combustion is the still-hot heat shield tiles (methane air is easy to ignite). Flight 13 did not break open, so the venting methane only burned with air for a bit, until venting stopped. There was no LOX spilled into those fires, so there was no violent explosion. The LOX-induced explosions are a phenomena seen since the V-2 test flights during WW2.
2. The risk of capturing a Starship with one of the arm-equipped towers at the South Texas site is not just fires and explosions from the propellants, but also the impact of moving tons of mass, if the ship fails to hover properly for the catch. That risk is now reduced with Starship vers. 3 after two successful soft splashdowns, but it is not zero! The earlier successes with vers. 2 DO NOT COUNT toward a reliability demo, that is a significantly-different vehicle powered by significantly-different engines.
They may risk a tower capture of Starship on the next flight, but if they do, it would have to be the older tower. The new one is the ONLY vers. 3-compatible launch facility that they have operational at this time. And the FAA may not permit such a flight yet, as that would require going all the way around the Earth, flying over populated land. Two successful entries without a breakup is all the relevant experience SpaceX has with vers. 3 Starship. The earlier vers. 2 successes are a different vehicle with different engines.
3. They are absolutely NOT ready to attempt a Superheavy booster capture with vers. 3! Flight 12's was a total loss from the hot staging flip. Flight 13's was successful for the hot stage and flip, and for the boostback burn, but failed to light off enough engines to decelerate to a soft splashdown. Inadequately thrusted, it struck the sea at approximately Mach 1. None of the earlier tower catches or splashdowns of the booster are relevant to the necessary reliability demonstration, because those were different vehicles with different engines. They do not count!
4. I do NOT need an AI to tell me any of that! I was (and still am) a pencil and paper engineer of the old school, with a lot of rocket experience and supersonic flight vehicle experience under my belt. Ground and flight testing was what most of those experiences were all about. And the point of most of it WAS reliability demonstrations. Plus I have experience getting things certified with the FAA. I know how they think and operate, and what is required to satisfy them. Musk still does not know how to satisfy the FAA, but Shotwell does. She is a real engineer in addition to being a manager. Musk is not, and never was, an engineer, despite his claims otherwise.
GW
Last edited by GW Johnson (2026-07-26 11:49:13)
GW Johnson
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#2337 2026-07-26 11:48:13
- Void
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Re: Starship is Go...
I understand, I was doing conversation, trying to evaluate relative risk.
It is not as bad as a whole stack blowing up a launch pad, like happened to Blue Origin.
I will not pretend even to myself that I am your equal.
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#2338 2026-07-26 11:58:17
- GW Johnson
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Re: Starship is Go...
I was pointing out that if either the booster or the upper stage fails to come to a controlled hover, in the correct position relative to the tower, then the collision will destroy both the stage and the tower, even if the propellants do not explode.
But the propellants will explode because the stage will break open in the collision and spill them, and so create even more destruction. That's true even if the stages are nearly empty upon arrival. There will be the equivalent of multiple sticks of dynamite, in even just a few tons of fuel and LOX, which all by itself is more than enough to destroy the facility. Lots of propellant, only some propellant, the facility is destroyed, either way. The only difference is how far the debris flies.
A full load explosion like Blue Origin experienced is more or less equivalent to a small atomic bomb, but once you are at the few sticks of dynamite level, it no longer makes much difference at all to the destructive effect: facility destroyed, either way. And that costs a lot of time and money to replace!
I know of one rocket company that destroyed a USAF test stand facility decades ago, with a mis-designed solid rocket booster. It blew up during a test at the USAF facility. They ended up having to take a $billion write-off in one year. They were never the same financially after that. That company went belly-up decades ago. Traceable to that mistake.
GW
Last edited by GW Johnson (2026-07-26 12:07:07)
GW Johnson
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#2339 2026-07-28 14:59:24
- tahanson43206
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Re: Starship is Go...
This post contains a report on the performance of the Starship heat shield from Flight 13...
https://gizmodo.com/starships-heat-shie … 2000791792
Starship’s Heat Shield Looked Great After Flight 13, But Experts Spotted Something Troubling
The megarocket's latest test flight went well, but SpaceX still needs to overcome a critical engineering hurdle.
By Ellyn Lapointe
Published July 28, 2026, 2:40 pm ETStarship in space during Flight 13 on July 24, 2026. © SpaceX via X
Starship Version 3, the biggest and most powerful rocket ever built, had an overall successful second test flight on Friday. Both the rocket and its booster demonstrated key capabilities, including the first deployment of SpaceX’s next-generation Starlink satellites, but experts say one thing still stands in the way of achieving Starship’s ultimate goal.
“Starship’s current thermal protection system is a dead-end for all missions that require full and rapid reusability,” Dan Rasky, a former NASA engineer who studied heat shield materials for nearly four decades at the agency’s Ames Research Center, told Ars Technica.
He and two other spaceflight industry experts—former NASA astronaut Charles Camarda and the head of the Trump administration’s NASA transition team, Charles Miller—reportedly analyzed images of Starship after it splashed down in the Indian Ocean on Friday. They didn’t love what they saw.
Credit where credit is due
Before we dive into the issues, let’s get a few things straight. Firstly, the heat shield absolutely did its job during Flight 13. Starship successfully reentered Earth’s atmosphere, and SpaceX reported that the heat shield was intact after splashdown.
Secondly, it’s undeniable that Starship’s heat shield performance has improved markedly over the last several flights. The proof is in the pictures. In the images below, you can clearly see how much more uniform the shield appeared after flights 12 and 13 compared to 10 and 11, with minimal tile loss and damage.
The difference between flights 11 and 12 is particularly encouraging. Flight 12 was the first mission to launch Starship V3, and in this spaceflight reporter’s opinion, the heat shield stole the show. One of the biggest differences between Starship V3 and its predecessor, Starship V2, is the heat shield tile array, according to New Space Tracker. The improved tile geometry and attachment clips that SpaceX used for this new rocket have certainly made a difference, and it appears these upgrades are progressing the shield’s design toward rapid reusability.
It’s also worth noting that SpaceX is very aware that creating a fully durable, reusable thermal protection system is the biggest technical hurdle for the rapid reusability of Starship. That’s why the company experiments with different tile placements and attachments and performs intentional stress tests during these flights. On Flight 13, six of the Starlinks that Starship deployed also gathered imagery of the heat shield prior to reentry.
With all of that said, when Rasky, Carmada, and Miller examined drone footage of Starship’s heat shield after the Flight 13 splashdown, their trained eyes picked up an important detail.
A long road still lies ahead
According to the experts, white streaks that appeared to originate at the boundaries between some of the heat shield tiles suggest that hot gas may have penetrated those boundaries. You can see the same streaks in the image of the Flight 12 heat shield above as well. What’s more, there were indications of cracked tiles and broken edges, according to the experts.
That doesn’t mean the shield wouldn’t be reusable, but it may require a significant amount of inspection and refurbishment before it’s ready to fly again. SpaceX’s ultimate goal is to be able to launch the same Starship and booster within hours of a previous flight. Right now, the company can’t even turn them around in days or weeks.
Rasky, Carmada, and Miller believe SpaceX needs to pursue a different approach. They told Ars Technica that Starship’s heat shield design is a good “incremental” step forward from that of NASA’s Space Shuttle, but that it relies on the same fundamental solution.
Miller previously recommended that NASA create a new initiative to invest in heat shield research, development, and demonstrations, but nothing has come of that yet. For SpaceX’s part, the company has shown no intention of investigating new approaches to thermal protection this late in the game. Whether they can improve what they’re already working with and achieve their highly ambitious objectives remains to be seen.
2 hours ago
Even the space shuttles had to be thoroughly inspected and re-tiled after every flight. It may be that only the booster is the reusable part and that a series of starships are rotated at first....
1 hour agoEven the space shuttles had to be thoroughly inspected and re-tiled after every flight
And that's what made the Space Shuttles exorbitantly expensive.
1 hour agoYep the material science basically doesn't exist. This is why NASA spent the entire shuttle program mucking about with ceramic tiles and high temperature glues.
1k to 10k+ Celsius plasma sand blasting across the hull at mach 25-35 during reentry.
All it takes is a microscopic flaw to create erosion u...
See more
1 hour agoin the end, leaving it to the private sector will cost more than the government because private companies and their insurers will end up with all the redundancy and labor-intensive processes that the government follows.
1 hour agoWould be interesting to see how the tiles a joined. Butted? Some sort of joiner style overlap?
1 hour agoI'm pretty confident that SpaceX will solve this problem. The iterative approach they've taken has always yeilded the correct answer. The progress made is incredible.
2 hours ago
The original article contains numerous images.
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#2340 2026-07-29 07:49:04
- GW Johnson
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Re: Starship is Go...
The technology and materials and procedures for a heat shield that can make hundreds of LEO entries without significant repair simply DOES NOT EXIST YET!
NO ONE has such a thing, not NASA, not SpaceX, not Boeing, not Lockheed-Martin, not Northrup Grumman, not Blue Origin, not anyone! To criticize SpaceX over that, is rather pointless, until and unless such a better technology is actually ready to apply.
The basic science and perhaps some exotic material candidates do exist, but that "state of the art" is decades away from being ready-to-apply, if it ever gets there at all. That little ugly fact of life is too often forgotten by far too many!
What SpaceX does have, is a heat shield that might fly several times, with some repairs made in between, much like we saw with Shuttle, and much like what happens with X-37B. Their backup underlayer is a good thing, something Shuttle and X-37B do/did not have. It appears to work. They have not flown it twice yet, simply because they have yet to recover a Starship for potential re-flight.
Once they start recovering Starships, we will see their heat shield re-flown, and we will (finally) see how much repair is required between flights. If that is less effort than what was required for Shuttle, then yes, they have made a big improvement! So what if it is not yet "perfect"? Whatever "perfect" really is.
The complainers anger me with their lack of proper perspective, and their lack of acknowledgement of the VAST difference between what might be possible, and what is actually practical to do.
GW
Last edited by GW Johnson (2026-07-29 07:50:41)
GW Johnson
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#2341 2026-07-29 08:02:56
- GW Johnson
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Re: Starship is Go...
I have been in occasional casual conversation with Dr. Ed Pope at MATECH in California, about whether any of his exotic new materials might have promise as larger-than-tiles heat shield panels, for applications like Starship, or for capsule-type heat shields.
There are a lot of issues to resolve before ANYTHING could be in the least practical for such application. There is low thermal conductivity versus strength to endure the loads, there is densification of the surface (only) to prevent infiltration of plasma into the material, there is differential thermal expansion between the cold side and the hot side, and between the heat shield panel and the substrate behind it, there is the issue of how you attach this panel to the substrate, and how to hang onto it as things expand and loads vary strongly. There is the issue of how to survive the burn-through risk when something cracks or breaks. There is the issue of atmospheric moisture condensing and freezing into the porosity of the material, possibly resulting in steam explosions when the material gets heated.
And if I was a real heat shield designer (I am not), I could probably list a lot more! I know just enough to actually ask some (not all) of the practical questions.
My point in this posting is to expose at least some of the VAST gulf between what might be possible, and what is really practical to do. And that gulf changes with time as materials and technologies change.
GW
Last edited by GW Johnson (2026-07-29 08:03:49)
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#2342 Yesterday 15:11:07
- RobertDyck
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Re: Starship is Go...
NASA's Ames Research Center developed DurAFRSI in 2003. It uses a foil of Inconel 617 metal over a quilt of Nextel 440 fabric and Saffil batting. Both Nextel 440 and Saffil are synthetic ceramic fibres. The metal foil surface should make it durable, as long as it's not struck by a solid object like a chunk of ice from an external tank. However, although it can withstand greater temperatures than other thermal blanket systems, it still can't handle the heat of the belly of a Shuttle orbiter re-entering the atmosphere at mach 25. Apollo capsule re-entered the atmosphere about mach 32 when returning from the Moon. DurAFRSI cannot handle either case.
I'm concerned. The heat shield on Starship appears to be an incremental improvement of the same technology as heat shield tiles on Shuttle. The black tiles were high purity silica (99.9%), foam with 94% air by volume. Densified on the side where it attaches to the spacecraft. Outer surface coated in a black glaze to radiate heat. Able to withstand up to 1,260°C (2,300°F). It can withstand extreme heat and extreme quenching (cooling) without fracture or cracking. My concern is whether that is good enough when returning from Mars.
AVCOAT was used by Apollo to return from the Moon. In 1969, after Apollo 11 returned form the Moon, NASA said their next target was Mars. The problem was returning from Mars required entering Earth's atmosphere at even higher speed. AVCOAT was not good enough. In 1970, NASA announced PICA. It was 3 times as heavy as AVCOAT, but would physically fit in the compartment for the Apollo heat shield, and would withstand the heat of returning from Mars. PICA was used for an unmanned mission in 1995, modified to be lighter, known as PICA-95. And SpaceX based their heat shield for Dragon on that, calling theirs PICA-X.
Ok, great. So Dragon has an ablative heat shield that will survive return from Mars. A one-time expendable heat shield. It could return from Low Earth Orbit 5 times, or from Mars once. But the heat shield on Starship? Is that able to return from Mars at all?
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#2343 Yesterday 17:16:58
- GW Johnson
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- From: McGregor, Texas USA
- Registered: 2011-12-04
- Posts: 6,251
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Re: Starship is Go...
Rob:
The short answer to your question "could the Starship heat shield survive a return from Mars?", is "NO".
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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