Using Starships as habitats

 When I first heard about used Starships as habitats on Mars, I thought of them as still being upright, and wondered how they would shield the people living in them from radiation.  Well, the obvious answer (duh!) is to lay them on their side, and cover them with regolith (the loose gravel, rock and dust covering the surface of the Moon  and Mars).  These analysts have written a piece discussing how this can be done on the Moon, but the same principles apply on Mars.

Returning to the Moon and establishing a permanent human presence is the next step in human space exploration. This necessitates the development of lunar infrastructure up to this task. This contribution presents a framework for rapid, cost-efficient, and supporting construction of a permanent and modular lunar base within the scope of what will be technically and legally feasible today. The proposed concept uses the SpaceX Starship Human Landing System as the foundation for a lunar base. The Starship will be placed horizontally on the lunar surface and transformed into a habitable volume. A workforce of modular rovers will aid astronauts in the construction process, and an array of countermeasures are presented to protect the astronauts from the effects of exposure to radiation, lunar dust, and extended hypogravity. Psychological and psychosocial factors are included to enhance individual well-being and crew dynamics. Physical and cognitive workloads are defined and evaluated to identify effective countermeasures, including specific spacesuit requirements. The proposed construction activities are to be organized as a multinational public-private partnership to establish an international authority, a concept that has been successful on Earth but has yet to be applied to space activities on a multinational level. A roadmap incorporating each part of the construction from human and technical perspectives is outlined. Other aspects that are critical to mission success include the cultural significance of the project, legal aspects, budget, financing, and potential future uses of the base. These solutions rely mainly on existing technologies and limited modifications to the lunar lander vehicle, making it a viable solution for the construction of a lunar base in the near future.

The finished 'building' will have 2.5 times the habitable volume of the ISS.  At a fraction of the cost -- the ISS cost $150 billion, each Starship will cost $5 million according to Elon Musk, but let's say $20 million to be conservative.  The thick layer of regolith will protect against cosmic 'rays' (really, high speed particles)  and solar radiation.  And relatively quick and easy to build, too.  

Musk's comments on in-orbit refuelling of Starship

Starship continues to develop, and its design just keeps on being tweaked.  For flights to the Moon or to Mars, Starship will have to be refuelled in orbit.  When Starship (then the BFR) was first mooted by SpaceX decades ago, refuelling was going to be "belly-to-belly" as it were, with the tanker lying adjacent to the Starship to refuel.  Actually, that "decades ago" is just a dig at SLS, NASA's incredibly expensive and horribly delayed rocket which is supposed to get us to the Moon.  In fact, SpaceX started development of Starship, then called BFR, just 5 years ago, in 2016.  After the initial plans, SpaceX then switched to what is inelegantly described as "butt-to-butt" fuel transfers.  But experience has shown that this is too dangerous, with extraneous fuel lines next to rocket engines just too unsafe.  So we're back to "belly-to-belly" refuelling.

This all came out when Blue Origin, Jeff Bezos's pet project, chucked a wobbly about SpaceX being awarded  part of the Artemis Moon landing project.   This report is from Teslarati.

After a much-anticipated GAO denial of Blue Origin and Dynetics protests over NASA’s decision to solely award SpaceX a contract to turn Starship into a crewed Moon lander, an in-depth (but heavily redacted) document explaining that decision was released on August 10th.

Aside from ruthlessly tearing both companies’ protests limb from limb, the US Government Accountability Office’s decision also offered a surprising amount of insight into SpaceX’s HLS Starship proposal. One of those details in particular seemed to strike an irrational nerve in the online spaceflight community. Specifically, in its decision, GAO happened to reveal that SpaceX had proposed a mission profile that would require as many as 16 launches to fully fuel a Starship Lander and stage the spacecraft in an unusual lunar orbit.

After around 24 hours of chaos, confusion, and misplaced panic, SpaceX CEO Elon Musk finally weighed in on the GAO document’s moderately surprising indication that each Starship Moon landing would require sixteen SpaceX launches.

Confirming many expectations, SpaceX’s solution to sending an entire single-stage Starship to the Moon, landing it on the lunar surface, and returning it to a lunar orbit (and maybe even Earth) goes as follows.

First, SpaceX will launch a custom variant of Starship that was redacted in the GAO decision document but confirmed by NASA to be a propellant storage (or depot) ship last year. Second, after the depot Starship is in a stable orbit, SpaceX’s NASA HLS proposal reportedly states that the company would begin a series of 14 tanker launches spread over almost six months – each of which would dock with the depot and gradually fill its tanks.

Third, once the depot ship is topped off, the actual Starship Moon lander would launch, dock with the depot, and be fully fueled. Finally, the fueled lander would fire up its Raptor engines and head to the Moon, where it would enter a near-rectilinear halo orbit (NRHO) – a weird high-altitude, elliptical orbit only necessary because NASA’s Orion spacecraft and SLS rocket are too underpowered to reach a more normal, functional orbit around the Moon.

After reaching NRHO, Starship would dock with Orion (or vice versa), receive its Artemis astronauts, land on the Moon for several days, and launch back to NRHO to return those astronauts to Orion. After its main mission is complete, it remains to be seen if Starship will have enough propellant left over to return to some kind of Earth orbit, where it could potentially be refueled and reused on future missions to the lunar surface.

In response to GAO revealing that SpaceX proposed as many as 16 launches – including 14 refuelings – spaced ~12 days apart for every Starship Moon lander mission, Musk says that a need for “16 flights is extremely unlikely.” Instead, assuming each Starship tanker is able to deliver a full 150 tons of payload (propellant) into orbit after a few years of design maturation, Musk believes that it’s unlikely to take more than eight tanker launches to refuel the depot ship – or a total of ten launches including the depot and lander. 

[Musk added, in a tweet (how else): 

"Without flaps & heat shield, Starship is much lighter. Lunar landing legs don’t add much (1/6 gravity). May only need 1/2 full, ie 4 tanker flights.  However, even if it were 16 flights with docking, this is not a problem. SpaceX did more than 16 orbital flights in first half of 2021 & has docked with Station (much harder than docking with our own ship) over 20 times."]

But, as Musk notes, so long as Starship gets anywhere close to its design objectives, it would be a non-issue even if each Starship Moon lander mission somehow required 16 launches. A step further, assuming that SpaceX proposed 16 launches per mission out of an abundance of conservatism, it’s fair to assume that a 12-day gap between tanker launches is also an extremely conservative worst-case scenario. Per Musk and SpaceX, Starship’s design goals call for multiple reuses of ships and boosters per day. Even if SpaceX falls a full magnitude short of those ambitious goals, Starship tankers should feasibly be able to launch every few days or maybe every week.

But thanks to SpaceX’s relatively conservative proposal, the company now knows that NASA is more than happy with Starship even if it falls something like 50% short of its payload performance goals and two magnitudes short of its reusability goals.

 

Starship refuelling in orbit.
Render by Erc X

As an aide-mémoire, here is my Mars timetable.

NASA chooses Starship for moon mission

 I suppose most of us are asking 'what took them so long?'  Though to be fair, it was possible until recently to wonder whether Starship would in fact work.  

From Teslarati

In one of the biggest NASA contracting surprises in years, the space agency has chosen SpaceX – and only SpaceX – to return humans to the surface of the Moon with its next-generation Starship rocket.

The Washington Post’s Christian Davenport broke the news a few hours before NASA’s scheduled announcement and teleconference, revealing that SpaceX beat out Dynetics and a Blue Origin-led “National Team” for a sole-source contract to build, launch, and land a custom version of Starship on the Moon for $2.89 billion. If that uncrewed testing is successful, SpaceX and Starship will be tasked with landing the first astronauts on the Moon in half a century as early as the in the mid-2020s.

While a Human Landing System (HLS) announcement was fully planned and expected to happen this month, virtually everyone following the process believed that NASA would continue to lean on the rationale behind selecting multiple providers for its Commercial Resupply Services (CRS) and Commercial Crew (CCP) programs. Having multiple distinct providers, spacecraft, and rockets available to accomplish the same tasks fundamentally insulates NASA (and the International Space Station that depends on those programs) from losing the ability to transport crew or cargo in the event that any one provider is delayed or suffers a major failure.

With a goal as complex as landing humans back on the Moon for the first time since the 1970s, redundancy and multiple distinct solutions would obviously be even more desirable. Entirely contrary to expectations, NASA instead announced that it had exclusively contracted with SpaceX alone for next phase of HLS development. Though SpaceX may have been the only competitor already testing something approximating real integrated flight hardware, NASA’s decision to sole-source HLS to Starship represents a significant gamble.

Simultaneously, though, the move is also extraordinarily pragmatic and indicates that one or several major decision-makers at NASA have taken less positive lessons from its commercial cargo and crew programs to heart. Crucially, over the first several years of the Commercial Crew Program (CCP), Congress systematically underfunded the development of two commercial crew spacecraft – one from Boeing and the other from SpaceX. As a direct result, the launch debuts of both spacecraft were delayed by several years, forcing NASA to continue relying on Russian Soyuz launches well into the 2020s to get its astronauts to the ISS.

Additionally, SpaceX – an unequivocal underdog and newbie next to Boeing in the mid-2010s – has drastically outperformed its traditional aerospace counterpart, beating Boeing to the punch and launching astronauts first. Boeing’s Starliner is now at least 18 months behind Crew Dragon despite costing almost 60% more.

The reappearance of Mars

 From Astronomy Picture of the Day.  An astonishing image; a fantastic photograph.  So clear that you can just make out Valles Marineris at Mars's equator.

Image Credit & Copyright: David Duarte and Romualdo Caldas

Explanation: Mars reappears just beyond the Moon's dark limb in this stack of sharp video frames captured on September 6. Of course to reappear it had to disappear in the first place. It did that over an hour earlier when the sunlit southern edge of the waning gibbous Moon passed in front of the Red Planet as seen from Maceio, Brazil. The lunar occultation came as the Moon was near apogee, about 400,000 kilometers away. Mars was almost 180 times more distant. It was the fourth lunar occultation of Mars visible from planet Earth in 2020. Visible from some southern latitudes, the fifth lunar occultation of Mars in 2020 will take place on October 3 when the Moon and Mars are both nearly opposite the Sun in planet Earth's sky.

Starship's orbital launch in 2020?

Source: NASASpaceFlight/BocaChicaGal 

From Teslarati:

Despite the spectacular demise of a full-scale prototype just days ago, a senior SpaceX engineer and executive believes that Starship could still be ready for its first orbital launch attempt before the end of the year.

Even if the first launch attempt fails, that milestone – if realized – would be one of the single biggest upsets in the history of spaceflight, proving that Saturn V-scale orbital-class rockets can likely be built in spartan facilities with common materials for pennies on the dollar. Much like Falcon 1 suffered three launch failures before successfully reaching orbit, there’s a strong chance that Starship’s first shot at orbit will fall short, although each full-up launch failure would likely cost substantially more than the current prototypes being routinely tested to destruction in South Texas.

Most recently, what CEO Elon Musk later described as a “a minor test of a quick disconnect” went wrong in a spectacular fashion, causing a major liquid methane leak that subsequently ignited and created a massive explosion. Although Starship SN4 did technically complete its fifth Raptor engine static fire test just a minute or so prior, the ship and its immediate surroundings were obliterated by the violent explosion, leaving little more than steel shrapnel and the broken husk of a launch mount behind. It’s in this context that one of SpaceX’s most levelheaded, expert executives believes that an orbital launch could still happen this year:

From Der Spiegel, interviewing Hans Königsmann, SpaceX's chief engineer:

SPIEGEL: SpaceX is already building the next largest spaceship, Starship, in Texas. This should be good for trips to the Moon and Mars. But a prototype has just been destroyed during a test. Is the program still on track?

Königsmann: The program is clearly separate from our work with the "Crew Dragon". It's about research. We want to see how far you can go with certain things. The goal is to learn as much as possible in a short time. Of course, if there are setbacks, it will slow us down. But that's part of it.

SPIEGEL: When will Starship fly for the first time?

Königsmann: First test flights to, let's say, 150 meters altitude, I expect in the coming weeks. [SN5  is nearly complete, and SN6 is well underway]  We'll do that a couple of times. If everything works out, we want to go into orbit at the end of the year. Or maybe it will take a little longer.

[Translated with help from Google Translate.  Read more of the interview here]

A reminder of my Mars expedition timetable (unchanged from last time):

The SpaceX/Mars timetable still looks doable, unless there is a disaster:

H1 2020: Tests to 20+ kms altitude.

End 2020: Full stack (i.e., Super Heavy booster plus Starship) operational.  First orbital flights of the Starship.

Early 2021: First commercial customers (for satellites), launches of Starlink constellation

Late 2022: Uncrewed mission to Mars (Mars is in opposition in December)

2023??: First commercial space station.  Launched on Starship, built by non-SpaceX companies—or maybe even by SpaceX

2023: 'Dear Moon' circumlunar expedition

2024??: Moon Base Alpha

Early 2025: Crewed mission to Mars  (How many ships?  Here's my analysis)

Early 2027: Second expedition to Mars.  Return of at least one Starship.  

2029: Third expedition to Mars.  Martian population reaches 300.  If Starship works, SpaceX will start designing even bigger rockets, capable of carrying more than 100 passengers, so Mars's population in 2029 could be more than 300.  Return of some Starships.

Boots on Mars by 2025.  Still on track.

Starship's Moon variant

When Elon Musk introduced the whole idea of a giant rocket capable of reaching Mars, the Moon, and most places in the solar system, he pointed out that it would simplify matters as well as save money if SpaceX had just one rocket which would be able to do point-to-point suborbital flights on Earth as well as journeys to Mars, the Moon and the moons of Jupiter and Saturn.  Almost immediately, this idealistic proposition had to be amended: there were going to be passenger (crew), fuel and cargo version of the BFS/Starship.  But the basic design would be the same.

At the same time, NASA expressed no interest in Starship, even though if Musk's cost predictions were correct, it would cost a hundredth of SLS, the NASA flagship rocket, which has been 20 years in the making, still hasn't flown, and will cost $1.5-$2.5 billion per launch.  That's partly politics—Congress has voted the money for the SLS because several states benefit from that expenditure, and it won't be voting money for Starship precisely because it will cost so much less.  But it's also prudence.  What if Starship doesn't work?  So to keep its options open, NASA has supported several suppliers for each of its main human space flight initiatives, and has pretended not to notice Starship.  Which is quite hard, really.

Now a variant of the Starship has been accepted as a candidate for ferrying astronauts from the lunar orbiter to the surface of the Moon as part of NASA's Artemis mission.  Starship is way too large for this.  Frankly, Starship could do the whole mission from the surface of Earth to the surface of the Moon and back, at a fraction of the cost.  But this way, NASA gets a look-in at Starship's development in the hope that it can slip Starship into place as a substitute for SLS, and SpaceX gets funding for Starship's development.  So we're getting a fourth variant of Starship, one that can land on the Moon, but can't land on Earth, as it will have no "fins".  Hmm.

Here's Teslarati's take on this:

SpaceX’s newly-announced Moon Starship is a fairly radical departure from the Mars-focused, fully-reusable vehicle the company has been pursuing for years. Unintuitively, that may be the perfect half-step towards truly reusable Mars rockets.

With a substantial amount of money [$135 million—Musk has said that each Starship could cost as little as $5 million, excluding development costs]now on the table for SpaceX to begin initial work on its Moon Starship, it’s worth analyzing just how different it is from the Starship the company is working on today.

SpaceX appears to have returned to a fully-painted vehicle for unknown reasons. [The] white paint is likely motivated by the fact that proposed NASA Moon landers must  be able to sit on the surface of the Moon after landing for at least several days, with longer stays being even better. For Starship, this means that the vehicle must likely be able to keep its cryogenic liquid methane and oxygen propellant from warming up and turning into gas, thus preventing it from igniting its main Raptor engines. White paint is at least a bit more reflective (and thus insulating) compared to Starship’s shiny steel hull but it could also hint at the use of more extensive insulation then sealed off with paint.

While visible in a render of the craft after landing on the Moon, a separate render just before touchdown fully revealed not only the addition of large vacuum-optimized retrothrusters – but a major strategic shift in how Lunar Starship will attempt to land on the Moon.

It appears that SpaceX does not plan on landing Lunar Starship on the Moon under the power of its main Raptor engines. Instead, three triple-thruster clusters – likely relying on the same methane and oxygen propellant as Raptor – will fire up shortly before touchdown to gently land Starship on the Moon. This approach has significant benefits: the Moon’s gravity is so low (~1/6th of Earth’s) that using even just one engine as powerful as Raptor to land would be incredibly difficult – a single engine could theoretically lift a fully-fueled Starship thanks to low lunar gravity.

Additionally, powerful Raptor engines – even if they could be used to land – would likely dig huge craters in the Moon’s powder-like surface during a landing burn, making it more difficult astronauts to leave the ship to explore their surroundings. However, it also means that SpaceX must design and certify an entirely new kind of vacuum-optimized rocket engine – likely using gas propellant and fed by high-pressure tanks – for an extremely critical part of operations.
 Beyond new thrusters, a radically different landing strategy, and a painted (and possibly insulated) steel hull, Lunar Starship also features what looks like the tip of a Crew Dragon spacecraft in place of its nose, likely including Draco thrusters and a docking port. SpaceX has also copied the concept of Crew Dragon’s trunk section, installing a curved solar array that wraps around a large portion of Starship’s conical nose. Lunar Starship also offers what looks like the first official glimpse into a new style of Starship landing legs, prototypes of which are already installed on Starship SN4.

Additionally, SpaceX has chosen to entirely exclude a windward heat shield from Lunar Starship, as NASA’s plan is (rather painfully) to launch astronauts to the Moon with SLS and carry them to lunar orbit and back to Earth on Orion. Starship also appears to be missing its complex and extensive habitation module and massive gallery window. All that absent hardware is almost certainly meant to dramatically simplify Starship to the point that even NASA would consider funding its development. Incredibly, that strategy appears to have worked and it’s possible that we could see Lunar Starships flying to the Moon as early as 2022.

While a stop at the Moon is decidedly one-way and requires a bit of a one-off Starship variant, what SpaceX has really done is found a way to get NASA to help fund the development of its fully-reusable next-generation launch system. Even if NASA’s Artemis program dies, flounders, or goes nowhere, SpaceX will likely still benefit significantly, much in the same way that NASA’s assistance developing Cargo Dragon and Falcon 9 was a huge boon for the company.

[Read more here.  Lightly edited for clarity]

New vs old Starship concepts
Note three oval openings of the triple thrusters half way up the body,
as well as the cargo bay and the lift.

Starship landing on the Moon using three sets of triple thrusters,
high up on the body.

Zubrin talks Starship with Musk

From an interesting YouTube video from What about it?, covering a conversation between Dr Robert Zubrin, president and founder of the Mars society, and Elon Musk, founder of SpaceX, which took place at the recent SpaceX employment fair in Boca Chica.

1.  There are currently 300 employees at SpaceX's Boca Chica operations.  This will be rapidly increased to 3000.
2. The new (again) LA facility will be used to build raptor engines, while Boca Chica will be where the rest of Starship and Super Heavy are assembled.  Musk plans to build 2 Starships a week.
3. Each Starship will cost—wait for it—just $5 million.  (The Super Heavy will be extra.) My earlier guesses were 10-15 times as high.  This is extraordinarily cheap.  It confirms that SpaceX will be running an  assembly line for Starship/Super Heavy.  Musk's earlier estimate of $2 million per launch (i.e., both Starship and Super Heavy) seems very plausible.  9 launches will be enough  to get a Starship to orbit and to refuel it for the trip to Mars, which means (at 100 passengers) a Mars ticket cost of just $180K.  Just a reminder: SLS will cost $1.5 to $2.5 BILLION per launch.  For the same cost, NASA could send 8000 astronauts to Mars.  Just saying.  Meanwhile, the whole fleet of 1000 Starships would cost just $5 billion.  You'll need fewer Super Heavys because they'll be re-usable several times a day, whereas Starships will have a more limited re-use because they'll be en route to Mars, or on the red planet itself, but on the other hand, the Super Heavys will cost at least twice the cost of the Starship itself.  So $10-$15 billion for the whole fleet?
4. The first 5 Starships will stay on Mars, which makes sense as they will be so cheap.  These will be the cargo versions of Starship, but there is no doubt they could be used as temporary habitats while permanent habitats are built.
5. No nuclear reactors (he means, presumably, NASA's KRUSTY kilopower reactors).  Zubrin pointed out that 6 to 10 football fields of panels would be needed to refuel a single Starship, and Musk replied "Fine!  That's what we'll do."   I still think that will require more Starships than SpaceX has been talking about so far, just to carry the solar panels.  But if Starships are so cheap ....  On the other hand, the next settlers may well be happy to have a diversified mix of nuclear, wind and solar, given the reality of planet-wide dust storms lasting months at a time.
6. The first crew ships will carry just 20-50 people, instead of the 100 each ship is capable of carrying.  Most prob'ly because  of the need for cargo space.
7. Musk also dismissed the whole "mini Starship" idea that Zubrin has been promoting.  Starships will be so cheap and production so rapid that leaving a Starship on Mars for 2 years (the Mars-Earth orbits only "sync" every 26 months) will only add a small amount to total costs.   
8. SpaceX will go for a 100 km high launch immediately after the 20 km launch.  Though he didn't say whether this would be SN1 (Serial number 1) or SN2 (both under construction at Boca Chica right now) which will attempt these landmark milestones.  100 kms (suborbital) will allow Starship to do point-to-point flights, and to circumnavigate the globe.  
9. Zubrin thinks that it is very likely that SpaceX will put boots on Mars before NASA gets to the Moon.  Looks very likely, doesn't it?
10. Progress constructing the first two test models of Starship, SN1 and SN2, has been extraordinarily rapid.  Subject to bureaucracy, the first test flights could happen as soon as April.

SpaceX ready to build first real Starship

SpaceX's progress building its new stainless steel Starship is extraordinary.  SpaceX's pivot away from carbon-fibre composites to stainless steel started just over a year ago.  Although SpaceX had lots of experience building carbon-fibre rockets, it had none with stainless steel.  Things have changed a lot since then.  And as usual, SpaceX is moving at incredible speed, and each apparent setback in fact gives them a chance to improve the design or the construction techniques.  In effect, each new rocket is a sort of prototype, tweaked and improved from the previous one.

From Teslarati:

After a busy several days of rocket hardware testing, Elon Musk says that SpaceX may be ready to build the first Starship prototype destined for space.

According to Musk, one test in particular – performed in South Texas just yesterday – is an encouraging sign that SpaceX’s Starship team is becoming increasingly competent at building the massive steel parts that will ultimately make up the generation launch vehicle. For SpaceX, the particular skills and expertise needed to precisely and consistently build a launch vehicle – let alone a rocket as large and complex as Starship – are quite a bit different from those it has mastered with Falcon 9, Falcon Heavy, and Dragon.

A lot of the expertise – particularly engineering talent, countless lessons-learned, and insight into reusability – is directly transferable from Falcon rockets to SpaceX’s Starship/Super Heavy program. Where it really isn’t transferable, however, is in the methods required to actually build the steel subcomponents that must ultimately be assembled together to form the rocket’s upper stage and booster. As a result, SpaceX has spent more than a year focused on building, testing, scrapping, improving, and re-testing any number of critical Starship components. Over the last four weeks (and last few days in particular), that testing has come to a head and Elon Musk believes the results have opened the door for SpaceX to begin building its first space-bound Starship prototypes.

SpaceX’s latest round of full-scale Starship hardware tests began just 10-20 days ago, depending on how one counts. Back around the start of the new calendar year, SpaceX began rapidly integrating two new Starship bulkheads and two cylindrical steel rings (barrel sections), ultimately delivering a finished ‘test tank’ after just 20 days of work. On January 10th, scarcely 24 hours after the two halves of the test tank were welded together, SpaceX sent the Starship test tank to its nearby launch pad and pressurized it with water until it quite literally burst.

Musk tweeted the results of that intentional test-to-destruction just a few hours after it was completed, revealing that SpaceX’s upgraded production and integration techniques enabled the tank to survive pressures almost 20% greater than the minimum Starships will need to perform orbital launches.

“Critically, the tank reached a maximum sustained pressure of 7.1 bar (103 psi), 18% more than the operating pressure (6 bar/87 psi) Musk says Starship prototypes will need to begin orbital test flights. At 7.1 bar, the test tank would have been experiencing an incredible ~20,000 metric tons (45 million lbf) of force spread out over its interior surfaces — equivalent to ~20% of the weight of an entire US Navy aircraft carrier. Perhaps even more impressive, that same Starship test tank was built from almost nothing extremely quickly, going from first weld to said pressurization test in just three weeks (20 days).

With relatively minor improvements to welding conditions and the manufacturing precision of Starship rings and domes, Musk believes that SpaceX can reliably build Starships and Super Heavy boosters to survive pressures greater than 8.5 bar (125 psi), guaranteeing a safety margin of at least 40%. Even a minor improvement of ~6% would give Starship a safety margin of 125%, enough – in the eyes of most engineering standards committees – to reasonably certify Starships for orbital test flights.”

In the last few days, two new bulkheads and steel rings came together to form Starship test tank #2, which was subsequently prepped for transport and moved about a mile down the road to SpaceX’s launch facilities on the morning of January 27th. Scarcely a few hours later, well before anyone was paying close attention for test activities, Elon Musk took to Twitter to reveal that the second tank had already been subjected to a pressure test with water. That second tank reportedly survived up to 7.5 bar, an improvement of about 6% compared to the first tank.

This time, however, the tank wasn’t actually catastrophically destroyed by the pressure test, instead developing a leak around the weld connecting the two halves that lead SpaceX to back off. Musk says that that presumably small leak will now be repaired, after which the same tank will be tested again but with one significant difference. Musk says that Test Tank #2’s second pressure test will be performed with a cryogenic liquid — most likely liquid nitrogen (LN2).

In replies after his reveal, Musk noted that he believed the second test tank could perform significantly better if pressurized with a cryogenic liquid. That’s because certain types of steel – particularly those SpaceX has chosen for Starship – exhibit something known as cryogenic hardening when exposed to extremely cold temperatures, producing steel that can be dramatically stronger by some measures.

Ultimately, as mentioned above, a tank pressure safety margin of 125% is the minimum most engineering standards provide for any given orbital-class launch vehicle. At 7.5 bar, even under the very unlikely assumption that Starship tanks will not see even a marginal strength increase at cryogenic temperatures, SpaceX’s second Starship test tank has officially hit that 125% safety margin. As Musk himself noted on Monday, he is now confident that SpaceX can immediately start building the first Starship destined for spaceflight and further revealed that two of that particular Starship’s three tank domes are already nearing completion.

From a piece I wrote earlier this month (slightly amended):

The SpaceX/Mars timetable still looks doable, unless there is a disaster:

H1 2020: Tests to 20+ kms altitude.

End 2020: Full stack (i.e., Super Heavy booster plus Starship) operational.  First orbital flights of the Starship.

Early 2021: First commercial customers (for satellites), launches of Starlink constellation

Late 2022: Uncrewed mission to Mars (Mars is in opposition in December)

2023??: First commercial space station.  Launched on Starship, built by non-SpaceX companies—or maybe even by SpaceX

2023: 'Dear Moon' circumlunar expedition

2024??: Moon Base Alpha

Early 2025: Crewed mission to Mars  (How many ships?  Here's my analysis)

Early 2027: Second expedition to Mars.  Return of at least one Starship.  

2029: Third expedition to Mars.  Martian population reaches 300.  If Starship works, SpaceX will start designing even bigger rockets, capable of carrying more than 100 passengers, so Mars's population in 2029 could be more than 300.  Return of some Starships.

What will delay the timetable by 2 years will be SpaceX having to ditch stainless steel and go back to carbon-fibre composites.

But Glyn Shotwell, SpaceX's COO, who is less given to "Musk time" than the great man himself, said (in October):

“We want Starship in orbit next year; we want to land it on the moon before 2022 with cargo and with people shortly thereafter,” Shotwell said.

However, much like Musk in his presentation last month, Shotwell hedged her estimate, saying that “every time I make a prediction about schedule I turn myself into a liar.” Most of SpaceX is focused on the company’s Crew Dragon capsule, which is undergoing a final series of tests before it flies two NASA astronauts.

“It’s a critical program for us, as it’s our first step to flying astronauts,” Shotwell said.

Shotwell said SpaceX wants to fly Crew Dragon frequently so the company can learn as much as it can about flying people safely.  

Implication:  they're ahead of the timetable—a Moon landing before 2022 and a crewed landing in 2022.  Will that bring forward the first expeditions to Mars?  Prolly not, because we can only journey to Mars roughly every 2 years.  However .......  If Starship lands easily and repeatedly on the Moon, in 2021 and 2022, proving that it's safe, will SpaceX be tempted to send the first expedition to Mars with a small (10-20) crew in 2022, and not wait for 2024 for the first crewed journey?  Will we see people on Mars in 3 years?  If Starship successfully lands again and again on the Moon, it's not that different in principle to landing on Mars, even though Mars is much further away.  That would be extraordinary.  SpaceX's rapid progress with Starship makes it seem just possible.

SpaceX Starship Moon Landing

A beaut rendering of Starship landing on the Moon by HazeGrayArt

Lab-grown food will save the planet

We know that we can transition electricity generation to renewables, and that process is now well under way.  By 2030, there won't be that many coal power stations left, because they will simply be too expensive compared to renewables plus storage. 

We know that, at some point quite soon, EVs will start to outsell petrol(gasoline)/diesel cars (ICEVs, which stands for 'internal combustion engined vehicles'), again because their up-front costs will fall below those of ICEVs as battery costs fall.  By 2030 at the latest, it is likely that EVs will make up 90%+ of total car/lorry/bus sales.  

We can produce carbon-free cement and iron/steel.  We will prolly, by 2030, have carbon-free sea and air transport.

What will be left then is agriculture. Agriculture is responsible for something between 24% and 30% of greenhouse gases emitted across the world.  And most of that comes from producing meat and milk.  Most people won't give these up, and in developing countries, rising meat consumption as living standards increase is likely to blow our carbon budget out of the water.  

Source: The Guardian, Illustration: Matt Kenyon

Here's an extremely interesting piece by George Monbiot in The Guardian bout how lab-grown food will save the climate and the world.  

It sounds like a miracle, but no great technological leaps were required. In a commercial lab on the outskirts of Helsinki, I watched scientists turn water into food. Through a porthole in a metal tank, I could see a yellow froth churning. It’s a primordial soup of bacteria, taken from the soil and multiplied in the laboratory, using hydrogen extracted from water as its energy source. When the froth was siphoned through a tangle of pipes and squirted on to heated rollers, it turned into a rich yellow flour.

This flour is not yet licensed for sale. But the scientists, working for a company called Solar Foods, were allowed to give me some while filming our documentary Apocalypse Cow. I asked them to make me a pancake: I would be the first person on Earth, beyond the lab staff, to eat such a thing. They set up a frying pan in the lab, mixed the flour with oat milk, and I took my small step for man. It tasted … just like a pancake.

But pancakes are not the intended product. Such flours are likely soon to become the feedstock for almost everything. In their raw state, they can replace the fillers now used in thousands of food products. When the bacteria are modified they will create the specific proteins needed for lab-grown meat, milk and eggs. Other tweaks will produce lauric acid – goodbye palm oil – and long-chain omega-3 fatty acids – hello lab-grown fish. The carbohydrates that remain when proteins and fats have been extracted could replace everything from pasta flour to potato crisps. The first commercial factory built by Solar Foods should be running next year.

The hydrogen pathway used by Solar Foods is about 10 times as efficient as photosynthesis. But because only part of a plant can be eaten, while the bacterial flour is mangetout, you can multiply that efficiency several times. And because it will be brewed in giant vats the land efficiency, the company estimates, is roughly 20,000 times greater. Everyone on Earth could be handsomely fed, and using a tiny fraction of its surface. If, as the company intends, the water used in the process (which is much less than required by farming) is electrolysed with solar power, the best places to build these plants will be deserts.

We are on the cusp of the biggest economic transformation, of any kind, for 200 years. While arguments rage about plant- versus meat-based diets, new technologies will soon make them irrelevant. Before long, most of our food will come neither from animals nor plants, but from unicellular life. After 12,000 years of feeding humankind, all farming except fruit and veg production is likely to be replaced by ferming: brewing microbes through precision fermentation. This means multiplying particular micro-organisms, to produce particular products, in factories.I know some people will be horrified by this prospect. I can see some drawbacks. But I believe it comes in the nick of time.

Several impending disasters are converging on our food supply, any of which could be catastrophic. Climate breakdown threatens to cause what scientists call “multiple breadbasket failures”, through synchronous heatwaves and other impacts. The UN forecasts that by 2050 feeding the world will require a 20% expansion in agriculture’s global water use. But water use is already maxed out in many places: aquifers are vanishing, rivers are failing to reach the sea. The glaciers that supply half the population of Asia are rapidly retreating. Inevitable global heating – due to greenhouse gases already released – is likely to reduce dry season rainfall in critical areas, turning fertile plains into dustbowls.

A global soil crisis threatens the very basis of our subsistence, as great tracts of arable land lose their fertility through erosion, compaction and contamination. Phosphate supplies, crucial for agriculture, are dwindling fast. Insectageddon threatens catastrophic pollination failures. It is hard to see how farming can feed us all even until 2050, let alone to the end of the century and beyond.

Food production is ripping the living world apart. Fishing and farming are, by a long way, the greatest cause of extinction and loss of the diversity and abundance of wildlife. Farming is a major cause of climate breakdown, the biggest cause of river pollution and a hefty source of air pollution. Across vast tracts of the world’s surface, it has replaced complex wild ecosystems with simplified human food chains. Industrial fishing is driving cascading ecological collapse in seas around the world. Eating is now a moral minefield, as almost everything we put in our mouths – from beef to avocados, cheese to chocolate, almonds to tortilla chips, salmon to peanut butter – has an insupportable environmental cost.

But just as hope appeared to be evaporating, the new technologies I call farmfree food create astonishing possibilities to save both people and planet. Farmfree food will allow us to hand back vast areas of land and sea to nature, permitting rewilding and carbon drawdown on a massive scale. It means an end to the exploitation of animals, an end to most deforestation, a massive reduction in the use of pesticides and fertiliser, the end of trawlers and longliners. It’s our best hope of stopping what some have called the “sixth great extinction”, but I prefer to call the great extermination. And, if it’s done right, it means cheap and abundant food for everyone.

Research by the thinktank RethinkX suggests that proteins from precision fermentation will be around 10 times cheaper than animal protein by 2035. The result, it says, will be the near-complete collapse of the livestock industry. The new food economy will “replace an extravagantly inefficient system that requires enormous quantities of inputs and produces huge amounts of waste with one that is precise, targeted, and tractable”. Using tiny areas of land, with a massively reduced requirement for water and nutrients, it “presents the greatest opportunity for environmental restoration in human history”.

Not only will food be cheaper, it will also be healthier. Because farmfree foods will be built up from simple ingredients, rather than broken down from complex ones, allergens, hard fats and other unhealthy components can be screened out. Meat will still be meat, though it will be grown in factories on collagen scaffolds, rather than in the bodies of animals. Starch will still be starch, fats will still be fats. But food is likely to be better, cheaper and much less damaging to the living planet.

Farmfree production promises a far more stable and reliable food supply that can be grown anywhere, even in countries without farmland. It could be crucial to ending world hunger. But there is a hitch: a clash between consumer and producer interests. Many millions of people, working in farming and food processing, will eventually lose their jobs. Because the new processes are so efficient, the employment they create won’t match the employment they destroy.

RethinkX envisages an extremely rapid “death spiral” in the livestock industry. Only a few components, such as the milk proteins casein and whey, need to be produced through fermentation for profit margins across an entire sector to collapse. Dairy farming in the United States, it claims, will be “all but bankrupt by 2030”. It believes that the American beef industry’s revenues will fall by 90% by 2035. 

[There's more, which you can read here]

For years I have wondered how it would be possible for passengers and crew on space stations and space ships, and on lifeless worlds like Mars or the Moon, to eat meat, fish or dairy.  The space and resources needed are simply impractical.  Lois McMaster Bujold, in her SF novels, talks about vat-meat, vat-chicken and vat-milk, and it is obvious that this is what will happen.  But it's equally likely that this will happen on Earth, too, as Monbiot points out.  Climate change, insectageddon, water shortages—everything points to the inevitable future where our meat and milk doesn't come from cows and pigs and chickens but from proteins grown in labs.  On top of which, it will be cheaper.  An order of magnitude cheaper.  We will be able to end world hunger, permanently.

This trend is starting now—even before we have food grown from bacteria.  I am a vegetarian, and I haven't eaten meat for 40 years.  To be honest, the very idea revolts me, these days.  So when I had one of the new, meat-like vegetarian burgers, which tasted like meat, "bled" like meat, and had a meat-like texture, I was rather put off!  But if you want to stop the horrible cruelty to animals which meat production involves, and if you want to reduce your carbon emissions now, by a good 20%, then you should try them. 

We need to start cutting emissions this year, and ramp up the reductions each year until we get to zero.  We need to stop exterminating insects.  We need to restore the soil.  These are compelling and vital steps, and we cannot dither and phaff any more.  To quote Churchill:  Action this day.

See also:

Imitation & vat meats the norm by 2040

Would giving up meat help the environment?

Agriculture's carbon footprint

Starbopper blows its top

The Starship fuel tank (nicknamed Starbopper) stress test went perfectly.  That's not how it looks, because the top blew off.  But that's just SpaceX's design and development technique.  It tests part to destruction to see what the design limits are.  Here's what Musk said after the test:

Dome to barrel weld made it to 7.1 bar, which is pretty good as ~6 bar is needed for orbital flight. With more precise parts & better welding conditions, we should reach ~8.5 bar, which is the 1.4 factor of safety needed for crewed flight.[i.e., 6 x 1.4]

A given tank pressure is needed to feed the engine turbopumps & pressure-stabilize/relieve compression load on the cylinder walls.  

Everything is compressible, but liquid compression at these pressures is not significant. However, the tanks do expand under pressure, creating a bit more volume. Keeping propellant super cold has a big effect on density of ~10% in case of CH4.

Every tank under pressure is a balloon tank — it’s just question of degree. Starship tanks are not balloon tanks like Atlas in sense that they don’t collapse when depressurized on the ground.

SpaceXcentric has a nice video showing Starbopper breaking under pressure. 

When I first saw this report, I was worried that it meant a delay in the Starship program, but I think in fact that the opposite is true.   It's fascinating to see a company shows us all its "failures" like this.  It makes their successes all the more impressive.  And because the rocket will be re-usable, it can be much more comprehensively tested than single-use rockets.

However, the timetable has slipped.  In July, I thought the first orbital tests would take place in late 2019/early 2020.  End 2020 looks more likely now, though altitude tests to 20 km look possible over the next few months.  Musk has made it clear that Starship can't get into orbit by itself, and needs the Super Heavy booster, and that won't even be built until the tank/bulkhead design is done for the Starship proper.

But the longer-term SpaceX/Mars timetable still looks doable, unless there is a disaster:

H1 2020: Tests to 20+ kms altitude.

End 2020: Full stack (i.e., Super Heavy booster plus Starship) operational.  First orbital flights of the Starship.

Early 2021: First commercial customers (for satellites), launches of Starlink constellation

Late 2022: Uncrewed mission to Mars (Mars is in opposition in December)

2023??: First commercial space station.  Launched on Starship, built by non-SpaceX companies—or maybe even by SpaceX

2023: 'Dear Moon' circumlunar expedition

2024??: Moon Base Alpha

Late 2024: Crewed mission to Mars  (How many ships?  Here's my analysis)

Early 2027: Second expedition to Mars.  Return of at least one Starship.  

2029: Third expedition to Mars.  Martian population reaches 300.  If Starship works, SpaceX will start designing even bigger rockets, capable of carrying more than 100 passengers, so Mars's population in 2029 could be more than 300.  Return of some Starships.

What will delay the timetable by 2 years will be SpaceX having to ditch stainless steel and go back to carbon-fibre composites.

Cargo Starship

Here's a nice render of the cargo version of Starship unloading rovers.  The cargo doors double as a lift, with the upper door supporting the lift cables and the lower acting as the lift floor.

Source: HumanMars

 

Starship's game-changing launch capabilities

Starship's payload bay opening to release Stralink satellites.
Source: Teslarati

From Teslarati:

SpaceX President and COO Gwynne Shotwell teased new information detailing the wealth of benefits that the next-generation Starship launch vehicle could bring for the deployment of the company’s Starlink internet satellite constellation.

Beyond Shotwell’s clear confidence that Starlink’s satellite technology is far beyond OneWeb and years ahead of Amazon’s Project Kuiper clone, she also touched on yet another strength: SpaceX’s very own vertically-integrated launch systems. OneWeb plans to launch the vast majority of its Phase 1 constellation on Arianespace’s commercial Soyuz rockets, with the launch contract alone expected to cost more than $1B for ~700 satellites [1.4 million each].

SpaceX, on the other hand, owns, builds, and operates its own rocket factory and high-performance orbital launch vehicles and is the only company on Earth to have successfully fielded reusable rockets. In short, although Starlink’s voracious need for launch capacity will undoubtedly require some major direct investments, a large portion of SpaceX’s Starlink launch costs can be perceived as little more than the cost of propellant, work-hours, and recovery fleet operations. Boosters (and hopefully fairings) can be reused ad nauseum** and so long as SpaceX sticks to its promise to put customer missions first, the practical opportunity cost of each Starlink launch should be close to zero.

In a perfect scenario, the only material cost of Starlink launches should be the satellites themselves and each expendable Falcon upper stage, which SpaceX has no plans to recover. Speaking prior to Starlink’s 60-satellite “v0.9” launch debut, SpaceX CEO Elon Musk stated that each prototype spacecraft ended up costing more to launch than to build, despite the fact that their first launch flew on a twice-flown Falcon 9 booster.

Musk thus implied that each Starlink satellite likely already costs significantly less than $500,000 even before SpaceX has begun to reap the full benefits of economies of scale. In fact, based on official 2016 figures that estimated the cost of each BFR booster/ship at less than $4M [it will be lower now, with a stainless steel spaceship] and Musk’s estimate that Starship could cut Starlink launch costs by a factor of 5, the cost of Starlink v0.9 production could have actually been as low as ~$350,000 apiece, with launch costs on the order of ~$20M.

Speaking a little over five months after Musk, Shotwell revealed that a single Starship-Super Heavy launch should be able to place at least 400 Starlink satellites in orbit – a combined payload mass of ~120 metric tons (265,000 lb). Even if the cost of a Starship launch remained identical to Starlink v0.9’s flight-proven Falcon 9, packing almost seven times as many Starlink satellites would singlehandedly cut the relative cost of launch per satellite by more than the 5X figure Musk noted.

In light of this new figure of 400 satellites per individual Starship launch, it’s far easier to understand why SpaceX took the otherwise ludicrous step of reserving space for tens of thousands more Starlink satellites. Even if SpaceX arrives at a worst-case-scenario and is only able to launch Starship-Super Heavy once every 4-8 weeks for the first several years, that could translate to 2400-4800 Starlink satellites placed in orbit every year. Given that 120 tons to LEO is well within Starship’s theoretical capabilities without orbital refueling, it’s entirely possible that Starship could surpass Falcon 9’s Starlink mass-to-orbit almost immediately after it completes its first orbital launch and recovery: a single Starship launch would be equivalent to almost 7 Falcon 9 missions.

[Read more here]

I talked about the synergy between Starlink and the BFS/Starship here and here.  It's ironic (and wonderful) that private enterprise will get us to Mars long before governments will, and with minimal government funding*, because the company has invented a new way to bring high-speed internet to every corner of the globe, which will fund the Mars expeditions and will thereby open up the solar system to trade and settlement, but which in turn depends on cheap launches.

The 100-fold-plus decline in costs brought about by SpaceX will also make space stations in Earth, Mars and Lunar orbit possible and practical.   I have no doubt that in 20 years' time, there will be several large privately-owned space stations in orbit round the Earth, at least one in orbit round Mars, and two or three thriving settlements on Mars.  The official timetables don't even have the Mars expedition until 2040.  It'll happen much faster than that, if my projected Mars timetable is kept to.


*I expect NASA, ESA, RosCosmos, and other state space agencies will be happy to buy berths on SpaceX expeditions to Mars at the same rates that private individuals will pay, i.e., something like $240K (or maybe less). On the other hand, NASA's estimate when Congress asked how much a Mars expedition would cost was $15 billion for 5 astronauts.  And we all know the likely final cost would have been double or triple that.  Just look at SLS.

** Actually, ad nauseam—learning Latin at school has some use, after all.