New Mars Forums

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

From AIAA’s “Daily Launch” email newsletter for 23 July 2026:

SPACE
After nearly 30 years, NASA realized this near-Earth asteroid is actually a comet. The discovery may help us defend the planet some day

Astronomers discovered that a near-Earth asteroid is actually a comet that could help scientists identify more hidden comets and improve planetary defense.

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My take on it:

Somewhere on these forums,  some years ago,  I opined that there really was no distinction between type C asteroids and comet cores,  except that “comets” have ices mixed in,  and the “asteroids” do not. 

Nearly everything we have seen of small bodies beyond Saturn would classify as “comets”,  and most things closer in have lost their ices to evaporation over geologic time,  and so we classify them as “asteroids”. 

There is the likelihood that ice content varied with formation distance from the sun,  yes,  but anything small that has remained in the same place over geologic time would have more or less found its equilibrium ice content.  Inward of Saturn,  that is likely pretty near zero.

The asteroid described in the article is a near-Earth asteroid,  but it very most likely has not been in that orbit for eons of time.  If it had,  it would be dry of ices. 

On the "asteroid defense" aspect:

If a body can be determined to have ices,  then a beam of laser or maser energy could be used to heat those ices under a local surface spot,  creating gas jets that might change the orbit over time.  Exactly how that might be done is not known at this time. 

This does require long warning time,  something we do not have for most perturbed "comets" coming in by surprise from somewhere out near the Oort cloud or Kuiper belt.

GW

The biggest problem that I have with all this is the scarcity of CO in the Martian atmosphere.  It is but a trace. 

For LOX-LCH4 propellants,  there is abundant CO2 in the atmosphere (above 90%),  and there may or may not be abundant water at any given site.  The Sabatier reaction allows you to make LCH4 from these,  assuming that you electrolyze the water resource for its hydrogen.

For LOX-LH2 propellants,  all you have to do is electrolyze the water.  You need nothing from the very thin atmosphere.  You just need to clean up the water.  Which you must do anyway,  for LOX-LCH4 propellants,  as well. 

There is a metal catalyst for making CO and O2 out of the far more abundant CO2,  but you must supply considerable energy to make it work,  just like with the electrolysis of water for the other two choices!  Given the lower Isp of CO + O2 combustion,  I do not see the point of that choice!  It's no better than solid propellants. The other two are far-higher Isp return.

GW

You have to understand,  there are a lot of scientifically-illiterate people "out there".  It goes along with all the other kinds of illiteracy that we all have seen.  Such folk cannot tell lie from truth,  and for many years the lie has been "fatal cosmic radiation". 

Those liars are looking for a scientific-sounding reason not to go out into space,  that's the motivation.  They need one that is not "treatable",  and it is extremely difficult-to-impossible to shield super-high-energy cosmic ray particles.  That's precisely the kind of excuse "not to go" that they are looking for.

They ignore the fact that cosmic ray intensity is entirely non-fatal in its effect,  leading only toward late-in-life cancers,  and even then only when exposed to the very worst intensities!  But the illiterate people they preach to,  cannot absorb that kind of detail.  And THAT is why the liars are still believed,  even after all these years.

They usually also completely ignore the highly-variable solar flare/mass ejection radiation,  which is very directional,  very erratic in intensity,  and very fatal at its larger intensities.  Why do they ignore it?  Because we already understand how to shield against it,  those particles being far lower energy than cosmic ray particles.  It's actually quite similar to nuclear fallout radiation,  which we have known how to shield since about 1945. 

The only "trick" has been figuring out how to do just enough shielding with something lighter than lead.  Turns out 15 grams/sq.cm of "something" might be enough,  and 20 grams/sq.cm of "something" is almost certainly enough,  even for the worst events we have seen. 

That "something" can be almost anything,  and if it is low molecular weight compared to the common metals,  there is very little secondary radiation produced by cosmic rays flying through it.  It would make sense to use as your "something" materials you already must have with you anyway for other reasons,  such as propellants,  food (especially frozen food),  water supplies,  and wastewater treatment volumes. 

There,  I just told you why it is that the radiation naysayers are liars.  Unfortunately,  the truth is beyond an illiterate audience to understand.  And THAT is why this lie-based argument has persisted for decades.

GW

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

You have to remember that both Starship/Superheavy and New Glenn are still early in flight test.  Which is where bad things inevitably happen.  That has been true since well before WW1.  Blue Glenn was 2 for 3 before this 4th attempt failed.  Starship/Superheavy is essentially a new design,  effectively about 0.5 for 1 so far. 

The Raptor-3's on the booster (and 5 of the 6 on Starship afterward) worked well up to the hot-staging point.  This is just an educated guess on my part,  but something looked “wrong” about that hot-staging event.  The plane of the booster flip was just about 90 degrees away from where I expected to see it.  And the flip “looked too fast”.

I thought the hot stage grid fin damage they had seen previously,  was to be avoided by going to 3 grid fins and letting the rocket blast on the booster take a path where the 4th fin was intentionally missing.  That didn't happen! 

And the flip looked too fast to my eyes.  If it really was too fast,  then centrifugal forces would unsettle the propellants in the forward tank,  despite the booster being under thrust during the flip,  and the booster engines then suck vapor instead of liquid.  Turbopumps sucking vapor instead of liquid,  come apart very rapidly,  or even explode violently.  Which causes destruction,  even explosion,  of the engine.  Any engine whatsoever!  All that has been well known since just after Goddard’s time.

So there was very likely something wrong with that hot-staging flip,  and whatever it was,  that led to the destruction of most of the booster engines,  and possibly damaged one engine on the upper stage. 

This flight had a new hot-stage shield built into the booster.  I may be wrong,  but it looks to me like that item and the interstage openings might not have done their jobs right!  And if what I suspect is true,  then that failure trickled-down to cause all the other catastrophic events. 

If I worked for SpaceX,  that is where I would start looking first.  Which does not detract from them still needing to fix propellant leaks. 

If I worked for Blue Origin,  I'd be looking for propellant leaks and sources of ignition,  initially with air,  knowing that oxygen hitting an ongoing fuel fire leads almost instantaneously to violent explosion. 

As for NASA,  they had no business betting their schedule on vehicles still early in experimental flight test.  In my own day,  nobody would have been that stupid at any company.  Although NASA did get away with that bet with the Grumman-built Apollo LM back in the late 1960's.  That orbital checkout on Apollo-9 was its first flight test.  Apollo-10 was its second flight test.  And Apollo-11 its third.  Etc.  Turned out Grumman did a good job. 

GW

Neither moon is geosynchronous with the planet.  You cannot build a proper space elevator to either of them,  stretching to the surface.  The lower ends would drag around the surface of the planet,  Phobos very rapidly indeed.  All you could do is build partial elevators bottoming out above the atmosphere,  meaning well above the entry interface altitude of 135 km at Mars.

GW

Here is what I posted under the ISS thread in "human missions"

From CBS News/Space:

Space

Space station crew briefly moves to "safe haven" amid new concerns over leak

By Miles Doran, Alex Sundby
Updated on: June 5, 2026 / 11:45 AM EDT / CBS News

Out of an abundance of caution, NASA on Friday briefly directed five of the seven crew members aboard the International Space Station to wait inside the docked SpaceX Crew Dragon "Freedom" spacecraft — known as a "safe haven" — amid new concerns over some cracks in a transfer tunnel in the Russian module.

NASA then told the crew members they were comfortable with backing out of the safe haven configuration and returning to normal operations after the Russian space agency Roscosmos paused repair efforts and decided to take measurements and assess data.

"We look forward to working with Roscosmos on a collaborative approach to address the leaks," NASA said in a statement.

The cracks have been the source of a small air leak that has persisted on and off for the last six years or so. The leak is considered a top safety risk. There have been several attempts over the years to repair the cracks.

"The cracks have always been a concern that NASA watches very closely," the agency said.

Friday's effort comes after Roscosmos noticed a slow pressure drop in the transfer tunnel last month following the arrival of a Russian cargo ship.

NASA said it and Roscosmos have been trying to determine the cause of the cracks while the Russian space agency addresses the issue through "operational mitigation measures and periodic partial-repair efforts."

After new leaks appeared, NASA initially said Roscosmos decided to move forward with a more extensive repair operation Friday before the Russians decided only to perform measurements.

"We continue to work with our Russian counterparts, along with the rest of the international community that supports the space station, to arrive at a more permanent resolution," NASA said.

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my opinion:  they bloody well know what the problem is,  metal fatigue from thermal cycling day/night every 90 minutes.  The tunnel wall was too thin to support such a long life while cycling.  The cracks are "everywhere",  but are very hard to see.  And they keep lengthening,  until something breaks apart. 

The way you stop a fatigue crack from lengthening further is to find its very end,  which is very,  very hard to determine without the right kind of X-ray or other detection equipment,  something very hard to do on a pressure vessel in space,  because your source is on one side pf the shell,  and the receiver must be on the other.  Plus,  in this case,  the tunnel is buried inside the outer structure of the module.  Then you drill a hole at that end of the crack,  to relieve the stress created by the sharp corner at the end of the crack.  Miss the end even slightly,  and your repair fails.  In vacuum,  your hole makes the leak worse,  until you can patch it with something,  along with the length of the crack.  Such cracks are rarely straight,  by the way.

GW

Here it is,  Tom:

Went to a picnic in McGregor yesterday (Sat 5-30-2026) sponsored by SpaceX,  and got a bus tour of their site.  First one of those sponsored picnics in about a decade,  and the first one I had been to.  Most of the old WW2-vintage buildings that I knew were gone,  but the old propellant lab ruins and the old machine shop buildings were still there.  So was the underground bunker control room for the big-motor stands,  although the associated big earthen revetment and firing stands are gone now.  My old ramjet test facility was near that propellant lab.

Spacex now has most (but not all) of its Raptor and Merlin test stands rigged with water deluge,  and located below the surface,  to deaden the noise.  I had noticed the noise reductions over the last year or so. 

There was a Raptor-1 sea level engine on display outside by one building,  and the surviving "Grasshopper" Falcon-core landing test vehicle outside by another.  It so happened there was a Falcon-9 core wrapped in plastic coverings and fitted to two sets of truck wheels as its own trailer,  waiting to go on the road for delivery.  The tour guide did not know if that was Canaveral or Vandenburg.  The old tower stand they inherited from Andy Beal is still there,  but they don't use it anymore.  Tests up in the air atop it are really loud,  even if only Merlins. 

There is a firing stand facility specifically devoted to Raptor vacuum engines.  I did not have the chance to question the tour guide about it,  but I saw no sign of any sort of exhaust diffuser equipment.  So the area ratio on the vacuum engines is limited to one that won't quite separate,  when fired in the open air,  at a high throttle setting.   Pretty much like I laid out in the rocket performance estimating lesson of the orbits+ course on the forums.  My empirical separation criterion is probably a bit too conservative for curved bell nozzles.  It was developed for the simpler conical bells typical of tactical solid rockets.  With a curved bell,  there are games you can play with nonuniform exit plane pressure distributions  (higher at the edge,  lower near the centerline),  to delay separation to slightly-higher backpressures than my old criterion would predict. 

I did notice they are very careful to tout the benign nature of the rocket exhausts with methane and kerosene, and that there were questions about that from the audience on the bus.  With big rockets,  those exhaust clouds do often leave the reservation.  Accordingly,  I noticed they say nothing about the exhaust fumes from the Draco and Super Draco  thrusters.  Those are very small in comparison,  and their exhaust clouds do not leave the reservation,  although they are quite toxic.   (I remember similar public concerns about fumes from the solids long ago,  which were well-known to everyone to be toxic.)

GW

I think it is silly to ballyhoo this into a race.  The Chinese do good work.  They will probably land a crew and get them home.  But that does NOT mean they are ready to build a base on the moon. 

I'm unsure that NASA is really ready to build a base on the moon.  They as yet have no crew lander,  and no large 1-way cargo landers,  both of which are prerequisites for building a base at all!  And thinking they can have either SpaceX or Blue Origin landers ready for crews in only a year is utter nonsense!  I know better!  Flight test does NOT go that smoothly!  It never has,  and it never will! 

They also still have no inexpensive (cost-effective) way to send things to the moon.  That requires assembly by docking and fueling at a space station in the right orbit.  ISS is in the wrong orbit,  and is wearing out to the point of endangering its crews.  Gigantic budgets are going to bust any of their plans.

I've seen this budget-busting thing before,  multiple times.  The Space Shuttle was a kluged-up cluster instead of a clean and fully-reusable two-stage airplane,  because of money.  NASA was forced to use an idea from outside the agency (regarding lunar orbit rendezvous),  in order to save money by getting down to 1 Saturn 5 launch per mission.  The USAF space plane efforts of the late 50's and early 60's were shut down in favor of NASA's space capsules,  because the country could not afford both approaches simultaneously,  and the capsules were ready to fly first. 

GW

Well,  I got the grid fin missing alignment wrong in my "exrocketman" posting.  I had the missing fin lined up with the belly mid-line.  It was really lined up with the dorsal midline.  I'll have to go fix that sketch.  But Scott Manley and I agree that the booster flip was 90 degrees away from where it should have been. 

My suspicion is that whatever caused that may be related to,  or even caused,  the engine failures.   And THAT is what they are going to have to find out for the FAA. 

Anyhow,  the video Oldfart found does a really nice job explaining why you want liftoff T/W 1.5 or higher.  And where the gravity loss comes from.  Once you have the right flip-over gravity turn,  higher liftoff T/W is your main influence on reducing gravity loss.  There are limits:  as you burn off propellant at the same thrust,  acceleration rises,  perhaps too high for what you are trying to accomplish,  in terms of structural design and/or what your payload can endure.

GW

I put my observations and speculations about Flight 12 into an article posted on "exrocketman",  including a couple of illustrations that make what I am trying to say a lot clearer and easier to understand.  The site is http://exrocketman.blogspot.com,  and the title is "Kudos to SpaceX for Flight 12",  dated today at 5-27-2026.  It's top of the page right now,  but later you can use search code 27052026,  the archive tool with date and title,  or the search keywords launch or space program.

GW