Cost of launches per kg will plunge

SpaceX's Starship fourth launch was a resounding success.  Both the booster and the ship came down for soft landings, even though one of the ship's fins was nearly burnt off by the heat of re-entry.  But compared with the first and second launches, when the Starship/booster combo exploded, and the third launch, when the Starship disintegrated during re-entry, these were huge successes.  Remember, SpaceX learns by iteration.  It tries something, then fixes any errors, then tries again, fixes new problems, tries again, and so on in a continuous program of improvement.  And the logic of the progress so far is that flight five (late July?) will be still more successful.  And flight six after that, and flight seven .....

By the end of this year, Starship will probably be carrying cargo to and from space.  And when it is, it will cut the cost of launching 1 kilo to orbit to around $20.  Musk says that each launch will cost $2 million, and each Starship can lift 100 tonnes into orbit.  Even if you allow for fat profit margins, making that, say $50/kg, it still means that a human weighing 100 kg could go to LEO (low earth orbit) for $5,000.  Though Musk says there will have to be hundreds of accident-free launches before Starship will be considered safe.  

That's just V-1 of Starship.  V-3, which will go into construction in a few months, will be even more efficient.   Its propellant load will increase 20%, but it will double its payload to 200 tonnes.  Cost per kg to orbit will fall to $12/kg.

The chart below, from Our World in Data, shows the cost of launching 1 kg to orbit since 1961, each observation adjusted for inflation since then.    SpaceX's first rocket, Falcon 1, cost $12,600/kg.  It was not re-usable.  The Falcon 9, which had a re-usable booster, but not second stage, cost $2,600/kg, half the cost of its nearest non-reusable competitor.  Falcon Heavy, three Falcon 9 boosters yoked together, cut the cost to $1500/kg.   And Starship V-3 will cut the cost to $20/kg.  Its data point will be right off the bottom of the chart.

It's impossible to know for sure how this will change the world.  But as Tony Seba says, a ten-times cost reduction leads to disruption and opportunity.   Since SpaceX started, it will have engineered a 250 times cost reduction for lifting one kilogram to LEO.   

This opens up the inner solar system to exploration.   The Moon and Mars will be in reach, affordably.  The cost of sending a single Starship to Mars will be $20 million in fuel (it will need 7 propellant ship launches to refuel it in space, each one carrying 200 tonnes of propellant).   Tripling that for food, life systems, etc., gives us a cost per ship of $60 million.  Even if we send 20 ships on the first expedition to Mars, with 10 astronauts per ship, with the rest of the payload devoted to food, shelters, water and air purification plants, rovers, and other things needed for survival on Mars, the total cost would be $1.2 billion.   That's less than half SpaceX's 2023 profit.  SpaceX could fund the first Mars mission with its own money, if it wanted to.

When asked to provide a costing for getting to Mars 20 years ago, in pre-SpaceX days, NASA estimated $100 billion (yes, with a b) for 5 astronauts, in then-money.   Things have come a long way since then.

The Dream Chaser space plane

 Competition is good, because it cuts costs.  The Dream Chaser space plane by SNC is another way to get to and from Low Earth Orbit (LEO), competition to SpaceX's Starship.  Like the Space Shuttle, it can land like a plane on a runway.  

The Space Shuttle was supposedly reusable, to cut the costs of launching to LEO, but in practice, checking and replacing the heat shield tiles was so expensive that it still cost billions each launch.  It was also not very safe, with two shuttles blowing up, one during launch, and one during re-entry.  It was retired 13 years ago, and all astronauts had to use the Soviet/Russian Soyuz rocket system to get to and from the International Space Station (ISS) until SpaceX's Dragon Crew Capsule started work.  

Musk's Starship is intended to colonise Mars, though it will be essential to launching all the Starlink satellites that will be needed to set up a mass universal satellite internet/phone system.   So the Starship lands vertically using retro-propulsion (the atmosphere on Mars isn't thick enough for wings to work).  This is tricky, though I don't doubt that SpaceX will eventually make it work.   

So, two alternate, competing technologies.  It --- at last! --- looks as if Dream Chaser will make its first test flight soon.  That is, if the rocket that is supposed to launch it is ready by then, which seems unlikely.  Perhaps SNC should have a chat with SpaceX, and use the Falcon 9 rocket to launch its Dream Chaser.

This video is a good explanation of Dream Chaser.

Starship―what now?

By choosing stainless steel to make Starship and its booster (=first stage), Super Heavy, SpaceX was taking a risk.  Up till now, for the most part, rockets have been made from carbon-fibre composite.  For example, SpaceX's Falcon 9 rocket, which has been remarkably successful, is of carbon-fibre.

No one knew how to make stainless steel rockets.  Steel is much heavier than carbon-fibre, though it has several advantages over it.  It can withstand much higher temperatures during re-entry, so needs a thinner and therefore lighter heat shield; it withstands the very low cryogenic temperatures of the fuel and oxidant better; it's far cheaper.  But it was all new.  When Starhopper (the first test version of Starship) was being built, YouTube and Twitter commentators thought it was a water tower! 

A couple of days ago, SpaceX launched its steel 'water tower', hovered it at 150 m, and landed it upright and safe, proving that it could be done.  So, what's next?

The next major hurdle is to land the Starship from a 20 km altitude.  To reduce speed, the Starship will use its flaps (or 'fins') in a 'skydiving' manoeuvre, falling sideways through the atmosphere, and then, at the last minute turning vertical and firing its Raptor rocket engines for the classic retro-propulsive landing we've often seen the Falcon 9 do.  We don't know whether such a manoeuvre will work.  We don't know whether the stresses applied to the long body of the spaceship by aerobrakes at each 'corner' will break it apart in the middle.  But we're going to find out, and soon.

The next critical hurdle is re-entry from orbit.  Starship will be entering Earth's atmosphere at 17,000 mph, or 27,000 kph.  The windward side will get very hot―2000 C.  Even steel will require a heat shield of ceramic tiles.  And this is a key aspect of easy re-use.  The Space Shuttle had to have each of its tiles inspected before re-flight.  If SpaceX has to do this after every flight then Starship will be far from re-usable.  However, SpaceX has already tested these tiles on a cargo Dragon capsule and they worked fine.

Then, if Starship is to go any further than LEO (low Earth orbit), for example to the Moon or Mars, it will have to refuelled in orbit.  Transferring cryogenic lox and methane between spaceships in space has never been done before.

Where are we in that testing process?

Musk has said that there will be several more 'hops', "to smooth out the launch process, then high altitude [20 km] with body flaps".    He said, in another tweet, that if the 20 km flight works, then the next test shortly thereafter will be an orbital flight.

SN8 (Serial number 8), the next Starship prototype, is ready for stacking at Boca Chica.  It will have a nosecone and functional flaps/fins, and three Raptor engines instead of just one.  It will fly to 20 kms, perhaps within a few weeks from now.  And then it will fly to LEO, if there are no problems.  Of course, there will be problems.  SpaceX's technique is to design, test to destruction, tweak the design, test again, tweak again, and so on, until it works.  I am certain we will see orbital flights of Starship before the end of this year.  

This is my latest estimate of the Mars timetable:

September 2020: Tests to 20+ kms altitude. First orbital flight of the Starship.

End 2020: Full stack (i.e., Super Heavy booster plus Starship) operational.

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  [Not part of SpaceX's plans]

2023: 'Dear Moon' circumlunar expedition

2024: Moon Base Alpha [Depends on NASA]

Late 2024/Early 2025: Crewed mission to Mars  (How many ships?  Here's my analysis, made before Musk revealed his planned very low cost of each Starship of $5 million. Perhaps the first uncrewed Mars Expedition could have as many as 10 ships, the first crewed 20, and the second crewed 40?)

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

2029: Third expedition to Mars.  Martian population exceeds 1,000.

The important point is that we are on track for a crewed expedition to Mars by 2024, which is after all still 4 and a half years away.  At SpaceX's current rate of progress that timetable is doable.

Read Teslarati's report here.

Starship SN8 being stacked at Boca Chica
Source BocaChicaGal/Teslarati

Starship's first 'hop'

SpaceX's Starship is new technology.  Its 'Raptor' engine burns cryogenic methane, not the purified version of jet fuel most rockets burn.  It was developed by SpaceX from scratch.  And Starship is built from stainless steel, not carbon-fibre composites, like most other rockets.

So there have been pauses for running repairs on the road.  Although the first cutback version of Starship, Starhopper, 'hopped' 150 metres, demonstrating the efficacy of the Raptor engine, all subsequent tests of versions of the Starship failed.

Until now.

The methane and liquid oxygen is held at 7.5 bars (i.e. 7.5 times the pressure of the atmosphere at sea level), and each tank tested (bearing in mind that they were made of a novel aeronautical construction material) sprung leaks, or exploded, or, in one case, imploded.  But with each failure, SpaceX learned something.  And yesterday, a real Starship, though without its nose-cone and fins, but still nine storeys tall, and with a steel cube to simulate the weight of a payload, lifted off from the company's base in Boca Chica, Texas, and 'hopped', reaching 150 metres altitude.

Of course, this is a long way from reaching Mars.  All the same, it is a huge step forward.  SpaceX has demonstrated that rocket ships can be built from steel. And can take off.  And land again.  The next step will be higher hops, and then testing of a full version of the spaceship, with a full complement of Raptor engines, flying to 20 km above the Earth, and trying to land again using the famous skydiver or belly-flop technique to burn off orbital velocity.






This is a prodigious achievement.  SpaceX only pivoted away from carbon-fibre composites to steel in December 2018.  Compare this swift development to the sluggish, even glacial, pace of conventional space companies and bureaucracies.

Stainless steel is about 3% of the cost of carbon-fibre composite, withstands both cryogenic temperatures and the 1500+ degrees C of re-entry.  Musk has stated that each Starship will cost just $5 million, and each launch of the Starship/Super Heavy combination under $2 million.  This compares with NASA's SLS (Space Launch System) of $1.5 BILLION  per launch.  Starship will lift 150 tons or 100 passengers to LEO (low Earth orbit).  This is a cost per kilogram of $13, compared with the cost, until SpaceX broke open the monopoly of dinosaur space companies, of $22,000/kg.   0.06% of the previous cost. 0.06%!!!!

Musk has stated that the really hard part of the whole process of constructing Starship and its booster Super Heavy is creating the assembly line that will build them. He's well on the way to doing this.  Already there is another prototype, SN 08, already close to completion.  It's being built of a slightly different steel alloy, as SpaceX continues to experiment and improve.  Starhopper took 8 months to build.  The latest versions of Starship seem to take 3 or 4 weeks.  The assembly line is speeding up.

Musk has said that he plans building 100 Starships a year.  He wants to send the first uncrewed Starships to Mars in late 2022, when Mars is in opposition to the Earth (in "orbit sync" as he pithily describes it)  The original plan was to send 2 cargo Starships in 2022 and 2 cargo and 2 crewed ships in 2024 to Mars.  But that was when the Starships would be constructed from carbon-fibre composites, and would be 10 times as expensive as the stainless steel versions will be.  Does that mean 20 cargo ships in 2022, and another 20 in 2024?  Or am I being overambitious?  Other SpaceX spokesmen have said that the first batch of Starships will be used as temporary habitats for the first settlers, in other words, they weren't going to return to Earth.  Only with subsequent missions would Starships return, because of the time that would be needed to make propellant on Mars to fuel their return journey.

Extraordinary.  Watch the video.  This is it—the first critical step on the road to making mankind multi-planetary.  I hope I live to see the first boots on Mars in 2024.