Space Sunday: Starship update

Starship S20, supported by the launch system “Mechazilla” arms, sits atop Super Heavy Booster 4, the Quick Disconnect Arm sitting between them, the sands of Boca Chica beyond. Credit: SpaceX

On Thursday February 10th, Elon Musk gave the first large-scale update on the work SpaceX is doing to develop the world’s first – and largest – fully reusable space transportation system in the form of the starship vehicle and its super heavy booster, and where things stand at present.

The presentation, which took place at the SpaceX Starbase facilities close to Boca Chica in Texas, came amidst on-going activity to both complete the first orbital launch facility for the massive booster and the payload-carrying starship vehicle, an in refining and finishing the first booster that will make an orbital launch attempt – Booster 4 and further testing of the first orbital attempt starship – number 20.

This incredible view, shared on Twitter but originator unknown, shows the base of Booster 4 as the rocket is lowered onto the launch table, the outer ring of 20 fixed Raptor motors surrounding the inner 9 that can be gimballed to provide directional thrust note the protective skirt between inner and outer engines.

In terms of the booster, this now appears to be pretty much launch complete: all of the anticipated protection has been added around sensitive equipment at the base of the rocket, the Raptor motors have been given a coat of protective paint, and work has been carried out into the rocket itself.

On the launch platform itself, work has been completed on the huge “Mechazilla” system that is designed to roll up and down the side of the launch tower, lifting both boosters and starships onto and off of the launch table using its two massive “chopstick” arms. Not only has the system, together with the Quick Disconnect Arm that provides fuel and power connections to the starship vehicle been put through their paces rising up and down the tower on their respective tracks, Mechazilla has also carried numerous tests using water-filled ballast bags to simulator the suspended weight of a booster or starship vehicle as it lifts, rotates and lowers them.

The Quick Disconnect (QD) Arm extends two claws either side of Booster 4, reaching for the hard points just visible below and between the grid fins. February 7th, 2022. Credit: Lab Padre

Such was the status of testing that many pundits had asserted that Mechazilla would be used to hoist both Booster 4 and Starship 20 from their transport cradles and hoist them up onto the pad and one another ahead of Musk’s presentation.

As it turned out, this was not quite the case. During the first part of the week ahead of Musk’s presentation, Booster 4 was moved the short distance to the launch facility, but one of the large cranes SpaceX has been using was used to hoist it from its transport platform and up on onto the circular launch platform, where clamps within the table’s ring to locked it into position. Following this upper Quick Disconnect (QD) Arm was positioned and connected.

The QD arm has two functions: holding the booster steady by extending two claws outwards and around the upper section of the booster so they mate with hard points mounted on the booster’s frame. Its second role is to similarly help secure a starship vehicle once stacked on top of a booster, and to provide with fuel and electrical power ahead of a launch. As the name implies, the QD arm is designed to rapidly disconnect from both booster and starship and swing out of the way at launch.

Gripped between its chopsticks, Mechazilla gently lifts Starship S20 upwards to where it can be swung over Booster 4. Credit: SpaceX

Following the securing of Booster 4, and under a night sky, Mechazilla did finally see action as Starship 20 was delivered to the launch facility and the huge arms of the mechanism were moved into position either side of the vehicle just below its forward canards and then gently closed so that they could engage with hard point on the starship before hoisting it clear of its transporter.

After what appeared to be a period of load testing / check out and a retraction / removal of the QD arm, Mechazilla was finally winched up the side of the launch tower, lifting Starship 20 up above Booster 4, prior to the mechanism and vehicle being rotated directly over the booster and then gently down onto it for mating with the booster, after which the QD arm rotated back into place and connected to both booster and starship.

Another view of the stacked Booster 4 and Starship 20 at the Starbase orbital launch facilities, Boca Chica. Note the tank farm, lower left. Credit: RGV Aerial Photography

This marked the third time booster and Starship had been mounted together on the launch table – but the first time in which both they, and the entire launch facility have been very close to being ready for that first launch attempt.

Mechazilla itself is a remarkable system. Not only will it lift and stack boosters and ships, it will (eventually) catch them out of the air. The animation below pretty much demonstrates how this will be done with a returning Super Heavy Booster, although after it was released, SpaceX revealed that rather than “dropping” onto Mechazillia’s arms, the booster will in fact come in to hover between the arms, which will them adjust their height and “hold” the booster, allowing the engines to shut down. When watching the video, note also the conveyors on the top of the Mechazilla arms correctly orient the booster ready for it to be swung over the launch table and lowered onto it, and also the V-shaped arms under the “chopsticks” that also connect to the booster to provide additional stability.

When embarking on an endeavour, success should be at least one of the possible outcomes, and for this design, that is the case. We’re aiming for rapid reusability, which is why the booster is going to take off and then fly back to the launch tower and, aspirationally, land on the arms. Which does sound insane!

– Elon Musk, on the plans to eventually catch returning vehicles

In terms of the presentation itself, little that was not already known was stated, and key points might be summarised as:

  • SpaceX still plan to launch Booster 4 / Starship 20 from Boca Chica providing the Federal Aviation Authority grant a launch license in March.
  • If for, any reason, a license is not granted, SpaceX will pivot flight testing to Kennedy Space Centre. This will cause a delay, but given the orbital launch facilities at Boca Chica went from planning to (mostly) constructed in 13 months, he is confident that with work now resumed in constructing similar facilities at Launch Complex 39A at Kennedy, a similar facility can be built there in 8-9 months.
  • With the new fabrication / assembly facilities being constructed at Kennedy Space Centre, it is likely that SpaceX will switch operational flights there, and use Boca Chica as the primary R&D and launch test facility.
The new starship / super heavy fabrication and assembly facilities being constructed at Roberts Road, Kennedy Space Centre. Credit: Greg Scott
  • It is hoped Phobos, the first of two sea launch platforms for starship / super heavy launches (two converted oil drilling platforms) will receive its launch support tower before the end of the year.
  • There is still an apparent desire to see Starship used as a sub-orbital point-to-point transport (say, Tokyo to San Francisco, for example) using multiple sea launch platforms.
  • The company hopes to be in a position to test orbital tank refilling by late 2023 / early 2024 – as Starship can only carry sufficient fuel to get itself and 100 / 150 tonnes to orbit, it will need to be supplied with additional propellants from a “tanker” vehicle before making forays into deep space – such as flights to Mars.
  • Allowing for some final technical issues to be resolved, SpaceX is hoping to make a full switch from the current Raptor 1.0 motor to Raptor 2.0. The latter is both fair more powerful than the former (230-250 tonnes of thrust compared to 185 tonnes), and much less complex, allowing production costs to be reduced.
  • Musk is finally giving thought to a launch abort capability for crewed starship vehicles, suggesting it might be a “good idea” to have them capable of being able to separate from the booster in the event of the latter malfunctioning during launch / ascent.

The presentation also included a new “official” video of a launch and journey to Mars (embedded at the end of this piece), again underlining the aspiration nature of this venture is moving humanity towards being a multi-planetary species.

While it is a remarkable vehicle, there is still a lot to be proven with starship / super heavy that – to me at least, as a rank amateur in this matters – seem to make it questionable, and almost based on the principle of “if we build it, they will come”.

Using their respective Quick Disconnect propellant ports (used to receive fuel when at the launch tower), a starship tanker (top) refills the tanks of a passenger-carrying starship in Earth orbit. Credit: SpaceX

For example: the presentation indicated that if carrying a 100 tonne payload, the cost of a starship launch would be around US $10 million. The SpaceX Falcon 9 averages around 5-8 tonnes to LEO at a cost of around $50 – so that’s quite a reduction. However, filling a 5-8 tonne capacity on a rideshare basis (thus reducing per customer costs) is a lot easier than trying to rideshare out 100 tonnes.

Even if, as has been estimated elsewhere, starship could offer a US $10 million launch cost when flying just 30-35 tonnes, that is still a lot of rideshare partners who need to be brought together. Thus, with commercial payloads trending towards smaller and lighter, an a host of lower-cost, small launch vehicles increasingly entering the market, it might not be that unusual for potential customers to shun starship, with a potentially long what for manifests to be filled, and instead opt to pay the extra – even if measured in a couple of millions or so – just to get a payload to orbit that much sooner. As such, it will be interesting to see how starship is received as a payload hauler as it becomes operational. Similarly, Musk’s ideas for a point-to-point transport system (passenger or cargo) also raise some serious questions in terms of viability / economics and safety (in the case of the proposal to carry passengers, if that is indeed still part of the equation).

Looking further out, and while I am a strong advocate for the human exploration of Mars (and the truth here is, for all the work a vehicle like the Curiosity rover has done over the course of a decade, the reality is, a trained human being could have done the same in a handful of months), I cannot help but feel Musk’s ideas are more dreams than properly thought through plans. If nothing else, the cavalier manner in which he has so often shrugged off the issue of galactic cosmic rays (GCRs),the more devastating and much harder form of radiation those travelling to (and from) Mars will face, still leaves me feeling he perhaps doesn’t understand the issue.

But all that said, starship / super heavy as undoubtedly a bold move; they could well (and perhaps likely will) prove some of my doubts wrong. But even if they don’t, it is about time someone stood up and tried to push the envelope in moving our abilities to reach out into the solar system forward. As such, success or fail, I’ll be watching the flight of Booster 4 / Starship 20 when it happens, and that of whichever booster / ship number follows them, and flights beyond that in the hope the system does succeed.

2 thoughts on “Space Sunday: Starship update

  1. “I cannot help but feel Musk’s ideas are more dreams than properly thought through plans.”

    I have no doubt people will take risks and lose before everything is properly figured out. I still think of the warnings about the O-rings but the decision makers pressed on anyways. Maybe that’s just the price to be paid for moving forward.


    1. Obviously, we cannot move forward without risk & loss (allowing for the more risk averse nature of western society today) – that’s a given, and we’re not going to engineer out everything or account for absolutely everything that can go wrong. The Challenger is proof of that in the way it brought together three disparate things – a design flaw, unheard of cold weather and undue managerial pressure to launch – to result in an arguably avoidable disaster.

      But that’s not what I’m referring to in the “Musk’s are more dreams” comment. Rather, I’m referencing the fact that there are some known, significant challenges involved in sending humans to Mars that need to be addressed (such as GCRs, as stated) which, due to their nature and presence, cannot be ignored or somehow magically “engineered away”, but which Musk seems to prefer to brush aside with glib comments as if they are of no real consequence, because trying to address them – and various NASA facilities have literally spent decades trying to do so – derails his broader vision.


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