What to expect on the next few Starship/Superheavy test launches
Superheavy/Starship lifting off on March 14, 2024
As noted last week by Eric Berger after the third orbital test launch of SpaceX’s Superheavy/Starship rocket on March 14, 2024, this rocket is presently only a few short steps to becoming an operational expendable rocket that can put 100 to 150 metric tons into orbit for about the cost of a Falcon Heavy launch.
To completely achieve this status SpaceX will still have to accomplish several additional engineering goals during the next few test flights, beyond what it has been done so far. This is what I predict therefore for the next test flight, number four:
Superheavy
SpaceX will once again attempt to softly bring Superheavy down over the ocean in the Gulf of Mexico, hovering the stage vertically over the surface for a few seconds to demonstrate it could do the same once it eventually comes down next to the launch tower so that the chopsticks can grab it. To do this the company will have to figure out what went wrong on last week’s flight, when the stage began to tumble as it dropped below 100 kilometers altitude. It also appeared to be unable to fire its engines as planned.
An even more important achievement on this third flight however will be a third straight successful hot fire stage separation, sending Starship on its way to orbit as planned. If Superheavy can do this for the third time, it will prove without doubt that the rocket stage is now capable of doing its number one job, launching payloads. Reusability can follow later.
Starship
Expect Starship to target another low orbit, bringing it down over the Indian Ocean. The inability to refire its Raptor-2 engines while in its coast phase on last week’s flight means this ability is not yet proven, and I can guarantee the bureaucrats at the FAA will not approve any landing zone closer to land than the third flight. The primary test goal will thus still be to prove Starship’s ability to fire its engines and de-orbit itself in a controlled manner. Until it does this, no full orbital flight will be approved, where an uncontrolled return to Earth could risk a crash anywhere.
During Starship’s coast phase SpaceX will not only again test the opening and closing of the ship’s payload door, I predict it is going to attempt to deploy one to two dozen Starlink satellites, simply to prove the deployment system can work. The satellites will not be in a stable orbit, so they will be not become operational Starlink satellites, but will subsequently and quickly be brought down controlled over the ocean, burning up in the atmosphere.
SpaceX will also do more propellant loading tests, to further refine this refueling technology necessary for its planned lunar and Mars missions.
Starship at about 54 miles altitude, on its way down.
Whether or not an engine restart succeeds, during the landing phrase the company will once again attempt to control Starship’s descent to test its heat shield tile system. The company needs to refine the tile attachment system so it does not lose tiles as the atmosphere thickens and the stresses rise, as happened on the third flight last week.
If the tile fixes work, the next goal will be to test vertical landing. Starship will be descending belly down, like the shuttle. Unlike the shuttle, which simply dropped its landing gears and landed horizontally on a runway, Starship once close to the ground must flip into a vertical position to fire its engines to softly touch down. This maneuver is unprecedented. SpaceX tested it successfully a number of times in its early Starship test hops at Boca Chica, but those were at much slower speeds. Can the spacecraft do this flip after returning from orbit at those much higher orbital speeds?
SpaceX needs to find out.
Assuming that on this fourth flight Starship successfully deploys some Starlink satellites, and also succeeds in refiring its Raptor engines to bring it down precisely at a targeted ocean landing site, the fifth flight will almost certainly go for a full orbit in order to deploy a cargo of operational Starlink satellites.
At that point Superheavy/Starship will be a fully operational expendable rocket, capable of putting two to three times the mass into orbit as a Falcon Heavy, and do so for about the same price. Its capabilities will outmatch every other rocket on Earth, many times over. Expect therefore from this point for SpaceX to highlight this reality by using every subsequent test flight to launch payloads and bring in revenues from those test flights, even as SpaceX continues its effort to bring both parts of the rocket back to Earth safely.
Not only will this effort sell the rocket to other commercial satellite venues, it will highlight starkly its superiority to NASA’s cumbersome and expensive SLS rocket. While Superheavy/Starship demonstrates its ability to launch every few months for about $100 million per launch (with that cost expecting to drop significantly once re-usability is achieved), SLS will only launch at best once or twice (if that) for a cost of anywhere from $2 to 14 billion per launch, depending on how you run the numbers.
Furthermore, Superheavy/Starship will soon be inherently more reliable and far safer. It will have flown many times, allowing engineers to refine its systems. It will also be built to be reusable, requiring that every component be designed to last through multiple launches.
SLS meanwhile will only have flown once or twice during this same time period. Its reliability and robustness will be questionable at best, especially as it was designed as expendable, which means its margins for failure will certainly be less robust that Superheavy/Starship. Why build a unit capable of flying five times when you know it will only fly once?
At some point during this SpaceX launch campaign the dimwits who run Congress and the White House are going to be faced with a choice: Either recognize that it is utterly stupid to continue funding the SLS rocket, or refuse to do so and prove to everyone that they are utterly stupid.
Sadly, I wouldn’t bet on the former, based on the track record in the last five decades of our federal government.
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From the viewpoint of elected officials, spending “anywhere from $2 to 14 billion per launch” of somebody else’s money to guarantee “jobs” and big-donations and votes is a no-brainer,
To them, failing to take advantage would be utterly stupid.
The dimwits in Congress are primarily concerned with 1.) Enriching themselves, and 2.) Getting re-elected. Thus, the Money will flow in such ways as will accomplish their goals. Since SpaceX is not a sprawling bureaucracy, spread across multiple Congressional Districts, employing zillions, it will never be showered with direct taxpayer funds but only receive contractural payments for services rendered. This is as it should be. NASA should be out of the Spacecraft business altogether, as it has consistently shown over the past 40 years that it cannot design and build an orbital spacecraft system for anything less than multiple tens of billions of dollars.
SpaceX is on the bleeding edge of spaceflight tech at present, and their success has encouraged many new start-ups. Young Engineers (who don’t know they can’t do it) are dreaming up wonders that will push us farther and faster. The future is indeed bright, provided the heavy, bureaucratized hand of Government does not snuff out the light.
I have a concern that one or more of the (at least) three major improvements needed may require a substantial redesign, preventing use of any of the already built boosters or ships:
1. Booster entry and landing without an entry burn may prove to be unworkable.
2. Ship cargo door may require complete redesign.
3. Ship reentry instability may require substantial aerodynamic changes.
The existing ships and boosters of course provided invaluable experience in developing both the design and the manufacturing process, but I wouldn’t be surprised if none of them turn out to fly.
I was wondering if they might deploy a reentry capsule capable of travelling with and watching Starship through reentry.
Open door, launch hobby rocket with camera.
I just read that Tom Stafford passed away.
Thanks to a presumed AI written bio, I learned he was one of 24 people to walk on the moon.
And this was on an avation(ist) site.
Can we please stop calling for an entry burn for Super Heavy? The thing is made of stainless steel and designed to take heating. There didn’t seem to be any indication that the booster was in a damaged state at low altitude.
The terminal velocity at low altitude will be determined by aerodynamic drag, not by what downward velocity it entered the top of the atmosphere at, at least within what we are talking about.
The cargo door? I’m sure the SpaceX folk have that issue in hand.
Ship instability on re-entry may have something to so with the way it hit atmosphere but not in stabilized attitude. Also unknown if still venting, which may have caused the instability overcoming the low aero forces. Ship works fine subsonic and in many ways hypersonic and supersonic flows are easier to predict. I have a lot of faith in the SpaceX GN&C people.
Hi, Mike thanks for your kind comments.
My overall point was not criticism, but that when you do the trade study between adapting features on an existing ship or booster and building a new one, they may conclude a new build is cheaper. I actually think they did remarkably well – so I am not criticizing but simply musing about the way forward.
Brewingfrog noted: “The future is indeed bright, provided the heavy, bureaucratized hand of Government does not snuff out the light.”
“That’s what Government is for; to get in a man’s way.”
Malcolm Reynolds
Serenity 2005
Not only will this effort sell the rocket to other commercial satellite venues…
Speaking of which, it seems that SpaceX just gave a tour of Starbase to some satellite company execs, using their newly acquired 737 as transport.
Tweet from Neel Kunjur, Co-founder and CTO of K2 Space:
Thanks @SpaceX for hosting us out at Starbase, had a great time sizing up just how many @K2SpaceCo satellites we’re going to launch in these!
https://twitter.com/neelkunjur/status/1769477084575891934
Tweet from John Gedmark, CEO of Astranis:
Finally got to Starbase. Incredible glimpse into the future.
Next up: catching a ride on the SpaceX jet to Washington DC.
https://twitter.com/Gedmark/status/1769499282506219575
The image in this tweet shows SpaceX’s newly acquired 737 taking on passengers.
h/t u/spacerfirstclass on the SpaceXLounge subreddit
Off Topic, but . . . Check out this brilliant idea — edit the Starship reentry video so the Earth is stable. Shows what the Starship was doing. Given there was also a door stuck open, it’s amazing it lasted that long.
https://twitter.com/ophello/status/1768481359209849070
Bob:
I largely agree with your assessment of the path forward but offer two refinements:
1. Superheavy needs to achieve recovery before it will be able to match or beat the cost of Falcon Heavy, and this is likely to require at least 3-4 more flights before they will attempt it I expect as cratering Stage 0 would be a very bad thing.
2. Regardless, SpaceX WILL begin Starlink deployments ASAP because they have proven the mass to orbit capability and recovery of either stage is completely independent. And as you note this provides a positive commercial value to these “test flights” mitigating a fair bit of their expense given Starship’s capacity.
I will add that during the refinement of Superheavy through this “expendable” test flight phase SpaceX will burn through a large number of Raptor 2s which leads me to speculate that by early 2025 they will be cutting over to an HVM (high volume manufacturing) configuration of Raptor 3 with uprated performance, reliability, and serviceability.
Finally, just a fun factoid to note. Over the last 2 launches 78 Raptor 2 engines performed perfectly and demonstrated about 4 HOURS of aggregate run time with no failures! The BE4 has a long way to go to catch up to that milestone!
Is it possible for there to be a size scaled down version of Starship that is launched into orbit by the Falcon 9 booster? That way, SpaceX could run frequent reentry and even refueling tests with this mini Starship. But I guess the raptor engines would have to be scaled down also. Or, would it help if there was a stainless steel version of the Falcon 9 2nd stage, equipped with heat tiles and maneuvering fins, that was used to learn how to control a rentry vehicle?
For SpaceX to start using Starship to launch Starlink satellites, the Starship must be able to go into an orbital plane that is useful to Starlink. If the disposal sites do not allow for this equatorial inclination, then Starlink must wait until Starship is ready for orbital status so that it can choose its own disposal site with reliability.
Once again, Starship and Super Heavy have shown them where to improve, adjust, and iterate.
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Robin K Juhl,
Thank you for that link. That was very informative and tells us how bad the spin was. As we can see, attitude control is very important for any orbital maneuvering engine firing, otherwise you just don’t know where it will end up heading after that test burn.
It is hard to say whether or not the tiles were lost due to the unexpected angle of attack, but they seemed to mostly be seen coming off at once, suggesting to me that it was an angle of attack problem, and they may have stayed attached if the attitude was under control. Either way, SpaceX seems to be getting better at keeping those tiles attached.
This is getting very exciting, and it is too bad that the government has set back the Starship development by a year or two.
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Mike Borgelt asked: “Can we please stop calling for an entry burn for Super Heavy?”
I am not so concerned about the stainless steel structure as I am about the engines. That three of them relit suggests to me that the stresses of the reentry are not too much for them, or that if it was too much for some of them, SpaceX is close to building them strong enough for a burn-less reentry.
Although I was surprised that they didn’t do a reentry burn, as there can be quite an amount of stress on the engines and engine compartment from the supersonic air, I see the advantage of not carrying the propellant to do so. A little extra weight strengthening the engines may save several tons of propellant.
The solution to the door may be in hand, or not. Large structures like that can be difficult to reseal, as NASA discovered with the Gemini door, but we know from the Space Shuttle that it is possible.
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Tweaking the Starship and Super Heavy designs is to be expected during developmental testing; that is what testing is for. Over the past sixty years or so, we have learned much about mechanisms in space and operating hardware in space, large as ISS or small as cubesats. Starship has a lot of heritage knowledge to start from, so I don’t expect them to be too far from doing it right, just a little tweaking.
I expect more tweaks and iterations for the rest of the decade as they learn how to do even better during operations. They did this with Falcon, too.
So, now comes the big question. Now that Starship has shown itself to be relatively safe, Does the FAA really need to hold its Spanish Inquisitions of the development iterations?
This is why I like wings….engines burn once… remaining propellant has time to settle down if a return burn must be had.
Regarding the booster:
Mike is right, reentry burn not required. It was obvious on the video that the reentry glide slope was not as flat as necessary, so it carried a lot more velocity into the landing phase. Plus, only some of the landing engines fired. You can see this on the video, and the timing of the reentry is different than the pre-planned timing. SpaceX will certainly work this out on subsequent flights. Based on their past performance, I’d bet on flight 4 getting to a soft water landing. Controlled hovering for capture might take a couple more to get the controls tuning right.
Regarding Starship:
Shotwell has stated that no Starlinks will fly yet. And it was obvious that Starship did an out-of-control reentry. SpaceX must solve the ship attitude control problem, along with the Raptor relight, for any significant progress on Starlink or reentry. Also, the dispenser door will need some work. We’ll have to watch and see how many changes they implement on ship 29, which should be the next to fly.
Oh, one last thing: How many of you were amazed like me at the quality of the streaming video from Starship courtesy of Starlink? I thought that was an incredible advancement in spaceflight technology! Crazy if that works all the way through the high temperature portion of reentry.
Re Chuck’s earlier comments on Booster above. Seemed to me that they combined the boostback and entry burns into a single boostback burn. If you compare a typical Starlink launch / recovery with what Booster gets, you end up with the following. Note that Falcon 9 numbers are from the 3/18 Starlink launch out of Vandy.
Booster: Topped out at 310 kph / 103 km
3,400 kph / 60 km (typical entry burn altitude)
4,500 kph / 25 km
1,400 kph / 2 km (typical landing burn start)
1,100 kph / impact
Falcon 9: Topped out at 7,170 kph / 113 km
7,900 kph / 63 km (entry burn start)
5,300 kph / 43 km (entry burn end)
5,400 kph / 32 km (aerodynamic slowdown starts)
900 kph / 2 km (landing burn start)
I thought Booster would have been fluffier, and slowed down by aerodynamic pressure more than it did before landing burn. It was going a lot faster a lot lower than I expected (at least 500 kph).
Maybe a better comparison would be a Falcon Heavy or any launch that returns the first stage back to the launch site. Will look into that. The 3/18 launch was readily available. Cheers –
Chuck asked: “How many of you were amazed like me at the quality of the streaming video from Starship courtesy of Starlink?”
Count me in as one of the impressed watchers. This is one of the ways that SpaceX is open to the public. Sometimes I complain that we don’t learn as much as I would like to know about test plans and what success should look like, but they do give us an amount of feedback that keeps us happy.