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SpaceX fires up next eight-flight Falcon 9 booster as Starlink launch slips

Ending a few-day delay, SpaceX has successfully static-fired Falcon 9 B1049 at Kennedy Space Center’s Pad 39A – now set to become the company’s second eight-flight booster as early as 6:19 am EST (11:19 UTC).

Originally scheduled to occur as early as Friday, January 29th, Falcon 9 B1049’s static fire test was delayed for unknown reasons and then aborted late into the countdown on the 30th before SpaceX was able to complete the test on Sunday afternoon. Pending official confirmation that the test results were positive, B1049 should now be on track to launch SpaceX’s 17th batch of Starlink v1.0 satellites (and 18th dedicated Starlink mission overall) this Tuesday.

Towed by tugboat Finn Falgout, drone ship Just Read The Instructions (JRTI) is en route to a landing zone roughly 630 km (390 mi) northeast of Cape Canaveral after a partially aborted departure (the loop visible below). The ships should arrive on-site within the next ~24 hours to support Falcon 9 B1049’s eighth landing attempt.

Simultaneously, tugboat Lauren Foss departed Port Canaveral with drone ship Of Course I Still Love You (OCISLY) in tow on January 30th, headed towards a recovery zone more or less identical to JRTI’s destination. OCISLY is scheduled to support Falcon 9 booster B1059’s sixth launch and landing no earlier than (NET) 1:19 am EST (06:19 UTC), February 4th, delivering Starlink-18 to orbit as few as 42 hours after Starlink-17.

Stay tuned for updates as SpaceX gets ready for an extraordinarily busy first week of February.

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Next SpaceX commercial crew mission to launch in April

WASHINGTON — The second operational SpaceX commercial crew mission to the International Space Station will now launch in mid-April, carrying astronauts from Europe, Japan and the United States.

NASA said Jan. 29 that it set a launch date of April 20 for the Crew-2 mission to the station. NASA astronauts Shane Kimbrough and Megan McArthur will be the commander and pilor, respectively, with Japan Aerospace Exploration Agency astronaut Akihiko Hoshide and European Space Agency Thomas Pesquet on board as mission specialists.

The four will replace the Crew-1 astronauts who flew to the station in November on the first operational Crew Dragon mission. NASA astronauts Michael Hopkins, Victor Glover and Shannon Walker, and JAXA astronaut Soichi Noguchi, will return in that spacecraft in late April or early May, assuming Crew-2 launches on its current schedule.

NASA earlier announced a no-earlier-than launch date for Crew-2 of March 30. However, it delayed the mission to allow the uncrewed Orbital Flight Test 2 mission by Boeing’s CST-100 Starliner commercial crew vehicle to launch no earlier than March 25 for an approximately one-week mission. Both Starliner and Crew Dragon dock to one of two ports on the station, one of which is occupied by the Crew-1 Crew Dragon spacecraft.

The delay to April 20 also accommodates a Soyuz spacecraft, Soyuz MS-18, scheduled to launch around April 10. It will bring three Russian cosmonauts to the station, with Soyuz MS-17 returning to Earth a week later with Russian cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov, and NASA astronaut Kate Rubins, on board.

“Around the mid-March timeframe we’ll really start to ramp up our preparations for doing some visiting vehicle operations,” Kenny Todd, deputy manager of the ISS program at NASA, said during a Jan. 22 briefing about an upcoming series of spacewalks at the station.

At the briefing he didn’t give a schedule for those missions. “We are still working with our Russian colleagues as well as the Commercial Crew Program to firm up the schedules for the Soyuz 64S and Crew-2 flights,” he said in a Jan. 27 statement to SpaceNews, using the NASA designation for Soyuz MS-18. “Both flights are currently targeting spring 2021, but specific launch dates have yet to be finalized.”

Two of the Crew-1 astronauts, Hopkins and Glover, performed the first in a series of spacewalks Jan. 27, working on the exterior of the Columbus module to support the Bartolomeo external payload platform and to install a new communications antenna there. A second spacewalk on Feb. 1 will complete the installation of a new battery for the station’s power system.

Another pair of spacewalks is tentatively planned for late February or early March, Todd said at the briefing. Those would take place after the arrival of a Cygnus cargo spacecraft currently scheduled for launch Feb. 20.

SpaceNews

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aerospace astronomy FAA Office of Commercial Space Transportation spacex Starship

FAA reviews delay SpaceX Starship test

Starship SN8 in flight

WASHINGTON — A test flight of SpaceX’s Starship launch vehicle is on hold as the company awaits approval from the Federal Aviation Administration, a delay that has publicly aggravated the company’s chief executive.

SpaceX had planned to perform a suborbital flight of its Starship SN9 vehicle at its Boca Chica, Texas, test site Jan. 28. The vehicle would have made a flight similar to that by the SN8 vehicle Dec. 9, this time going to an altitude of 10 kilometers before landing back at Boca Chica.

However, temporary flight restrictions (TFRs) closing airspace around the test site were unexpectedly lifted around the middle of the day, even as SpaceX was preparing the vehicle for the flight. A source familiar with the discussions between the FAA and SpaceX said that the agency requested additional information about the vehicle and flight plan before giving final approval.

SpaceX Chief Executive Elon Musk berated the FAA for the delay. “Unlike its aircraft division, which is fine, the FAA space division has a fundamentally broken regulatory structure,” he tweeted. “Their rules are meant for a handful of expendable launches per year from a few government facilities. Under those rules, humanity will never get to Mars.”

The company proceeded with launch preparations Jan. 28, leaving some to wonder if the company might perform a launch without a TFR in place or other FAA approvals. That turned out to be a wet dress rehearsal, with the vehicle fueled but the countdown halted before engine ignition.

A second launch attempt Jan. 29 did not get nearly as far. An FAA air traffic advisory early in the day stated that the launch had been canceled, although the TFR remained in place. By midmorning, though, SpaceX said it was now targeting no earlier than Feb. 1 for the SN9 launch.

Neither SpaceX nor FAA have disclosed additional details about the issue preventing FAA approval for the launch. “We will continue working with SpaceX to resolve outstanding safety issues before we approve the next test flight,” FAA spokesperson Steven Kuhn told SpaceNews Jan. 29.

The conflict between the FAA and SpaceX stands in contrast to the FAA’s public stance of working constructively with industry. That has included a streamlining of launch and reentry regulations the FAA concluded last fall. Those new regulations take effect 90 days after their official publication in the Federal Register Dec. 10.

At an appearance Jan. 26 at a space investment webinar by IPO Edge, Wayne Monteith, FAA associate administrator for commercial space transportation, said he understood the industry’s desire to move quickly. “As soon as that rocket’s ready to go and that payload’s ready to go, they want to go. So that we don’t become an impediment to the success of U.S. companies, we, as the primary regulator in this industry, have to be ready as well.”

Monteith said he was willing to talk directly with launch company executives if there were regulatory issues. “CEOs and presidents of companies also have my direct line. They can reach out to me directly if our teams are miscommunicating or not communicating well with each other,” he said. Issues that might take staff “weeks or months” to resolve, he said, “we can sometimes fix in a single phone call.”

“While nobody likes to be regulated, it’s important,” he said. “For one, it keeps everyone safe, and number two, it provides that stable environment for investors.”

SpaceNews

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aerospace astronomy falcon 9 News spacex starlink Top Story

SpaceX’s Starlink fleet is about to cross the 1000-satellite mark

While SpaceX technically launched its 1000th Starlink satellite on January 20th, the company’s next launch could give Starlink 1000 working satellites for the first time ever.

Pushed from January 27th to no earlier than (NET) Sunday, January 31st by an apparent lack of drone ship availability, SpaceX’s 17th Starlink “v1.0” launch and 18th dedicated mission overall is on track to add another 60 satellites to the constellation. If the launch is successful and at least 90% of spacecraft are in good health after deployment, SpaceX will find itself with up to 1022 Starlink satellites – at least 1000 of which are functional.

NextSpaceflight reports that SpaceX has assigned Falcon 9 booster B1049 to Starlink-17, meaning that the company is about to launch another booster for the eighth time less than two weeks after Falcon 9 B1051 became the first to do so. Unlike B1051, though, which exemplified SpaceX’s recent decision to only static fire flight-proven boosters on a data-driven basis, Spaceflight Now says that Falcon 9 B1049 will be static fired prior to its eighth launch attempt.

Perhaps just four days after B1049’s Sunday launch, another SpaceX Falcon 9 rocket is scheduled to launch 60 more Starlink satellites on February 4th. As of January 28th, Starlink-17 is scheduled to launch no earlier than 7:02 am EST (12:02 UTC), January 31st, followed by Starlink-18 as soon as 1:19 am EST (06:19 UTC) on Thursday, February 4th. At least two more Starlink missions are nominally scheduled to launch in February.

Altogether, if it manages to squeeze Starlink-17 in before the end of January, SpaceX will have completed the first of ten or eleven four-launch months needed to achieve its target of 48 launches in 2021. SpaceX completed four launches in one month for the first time ever in November 2020, making an average cadence of four launches per month a clear uphill battle. However, a 48-launch year will become substantially more plausible if SpaceX manages to launch Starlink-17 this Sunday, turning a possible fluke into something demonstrably repeatable.

As Starlink launches begin to ramp up again, SpaceX’s satellite constellation growth is poised to skyrocket. For unknown reasons, a vast majority of the ~~950 Starlink v1.0 satellites currently in orbit are performing phasing maneuvers, meaning they have dropped slightly below their operational altitude to tweak specific orbital parameters. Once the constellation stabilizes and all current satellites complete their orbit-raising, Starlink – around 1000 operational satellites strong – should easily have the capacity and coverage for SpaceX to begin a dramatic expansion of its internet beta.

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SpaceX, Elon Musk clash with the FAA over Starship launch license delays

In a bizarre series of events, SpaceX and CEO Elon Musk spent the day visibly clashing with the US Federal Aviation Administration (FAA) over Starship launch licensing delays.

Just six weeks ago, Starship serial number 8 (SN8) nearly aced the SpaceX’s first FAA-approved high-altitude launch debut out of South Texas, demonstrating the rocket’s ability to safely launch to high altitudes and return back to earth. Though a pressurization issue ultimately caused SN8 to lose thrust and impact the ground before it could gently touch down, the Starship made it a full six and a half minutes into a roughly seven-minute test flight before anything went wrong – a degree of success far greater than almost anyone at SpaceX confidently expected.

In the leadup to a bizarre last-minute abort of what may or may not have been Starship SN9’s first real launch attempt, Musk had some strong words for the FAA’s space division, deeming its regulatory structure “fundamentally broken” and a regime under which “humanity will never get to Mars.” Not long after that and in the midst of a great deal of uncertainty and mixed messages about the status of the rocket’s FAA launch license, SpaceX appeared to begin loading Starship SN9 with liquid oxygen and methane propellant.

Because a launch flow is virtually indistinguishable – aside from paperwork – from the process of preparing a Starship for a wet dress rehearsal (WDR) or Raptor engine static fire, it’s impossible to know if SpaceX was attempting to hedge its bets or simply taking advantage of established readiness to perform additional ground tests.

According to vague but official comments from the FAA provided to Washington Post reporter Christian Davenport, the licensing issue “is related to SN9,” which could imply a vehicle hardware or software issue but could just as easily be true for almost anything even tangentially related to the launch (range, ground systems, politics, semi-arbitrary risk analysis, etc).

Ultimately, perhaps just a minute or less away from a possible static fire or launch, SpaceX aborted Starship SN9’s mysterious January 28th test and gradually detanked the rocket over the next few hours.

Around 3:50 pm CST (UTC-6), SpaceX officially notified Boca Chica Village’s last few private residents that they could safely return to their homes (roughly 1.5 miles away from the launch pad), confirming that Starship SN9 will remain grounded until no earlier than 9 am (ish) to 2 pm CST, January 29th. However, it remains to be seen if the issue FAA has taken with something “related to” Starship SN9 can be quickly resolved, effectively leaving the rocket’s high-altitude launch debut in limbo until more information is made available.

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SpaceX drone ship fleet aces two Falcon 9 booster recoveries in 48 hours

SpaceX’s two-vessel drone ship fleet has successfully returned two boosters from sea to port in the space of just ~40 hours, an impressive feat that simultaneously shed light on a new kind of bottleneck for Falcon launches.

Completed on January 20th and 24th and originally planned as few as 25 hours apart, SpaceX’s back-to-back Starlink-16 and Transporter-1 launches made it clear that drone ship availability could quickly become a constraint as the company eyes increasingly ambitious launch cadence targets. CEO Elon Musk has stated that SpaceX is targeting up to 48 launches in 2021, translating to an average of one launch every 7.5 days.

As it turns out, measured from port departure to port arrival, that target is practically the same as the average amount of time it takes one of SpaceX’s two drone ship landing platforms to complete a booster recovery. Both existing drone ships must be slowly towed to and from the booster landing area, generally involving a minimum round trip of 800 miles (~1300 km) and some five days in transit.

Falcon 9 B1051 returns to port after its eighth successful launch, becoming SpaceX’s newest fleet leader. (Richard Angle)

In other words, even given a perfectly optimized schedule in which SpaceX launches missions requiring at-sea recovery every ~180 hours throughout 2021, each mission would have just a handful of days worth of margin before one launch delay would inherently delay another launch. Fundamentally, with a fleet of two drone ships requiring an average of five days of transit time per recovery, SpaceX could theoretically support as many as ~70 booster recoveries annually assuming zero downtime, no launch delays, and mere hours spent at the landing zone before turning around and heading back to port.

To be clear, recovery ship availability is an excellent problem to have, as it implies that SpaceX is fast approaching a rate of launch (and routine rocket landings) unprecedented in the history of commercial spaceflight. Thankfully, SpaceX also has an exceptional track-record of solving hard problems and there remains a great deal of ‘slack’ to be optimized out of its fleet of recovery ships.

~48 hours later, Falcon 9 booster B1058 sailed into port aboard drone ship Of Course I Still Love You (OCISLY). (Richard Angle)

That is all to say that removing the fundamental bottlenecks posed by SpaceX’s existing fleet will absolutely require at least one or two new drone ships on top of at least two major oil rig conversion projects in work for Starship. Whether in the form of one or more new converted barges or some kind of faster, self-propelled vessel, it’s safe to say that new ships are virtually guaranteed and likely close at hand unless SpaceX has decided to accept a semi-arbitrary ceiling on annual East Coast launches.

Just one month into 2021, SpaceX’s two drone ships are already being stretched to their operational limits to the point of launch delays. Delayed from January 17th to January 20th, Starlink-16 held up drone ship Just Read The Instruction for several days, resulting in the vessel returning to port on the 24th, just ~60 hours prior to Starlink-17’s original January 27th launch target. With drone ship Of Course I Still Love You (OCISLY) already indisposed at sea to support SpaceX’s January 24th Transporter-1 launch, SpaceX had to move Starlink-17 to January 30th.

After a few days in port for booster processing and maintenance, drone ship JRTI ultimately departed Port Canaveral for Starlink-17 on the evening of the 27th, most likely delaying the launch to Sunday, January 31st. For now, though, Falcon 9 booster B1049 is scheduled to launch for eighth time no earlier than (NET) 7:24 am EST (12:24 UTC), January 30th. Simultaneously, drone ship Of Course I Still Love You will likely need to depart Port Canaveral later this weekend to support Starlink-18, scheduled to launch as soon as 1:19 am EST, February 4th.

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SpaceX’s thin-skinned Starship ‘test tank’ passes first trial

CEO Elon Musk says that a new thin-skinned Starship ‘test tank’ just passed its first trial, taking advantage of delays to Starship SN9’s planned high-altitude launch debut.

Delayed by a lack of FAA approval for unknown reasons, Starship SN9’s 12.5-kilometer (7.8 mi) launch debut (virtually identical to SN8’s 12.5 km launch last month) is in limbo pending an “FAA review” according to Musk. SpaceX thus found itself with at least 24 hours of guaranteed inactivity for Starship SN9, time the company rapidly chose to fill with crane transportation and, more importantly, the first Starship ‘test tank’ stress test in months.

Known as Starship SN7.2, SpaceX’s latest ‘test tank’ is the third to carry the SN7 moniker and appears to have been built primarily to test refinements to the rocket’s structural design. Following test tanks SN7.0 and SN7.1, both used to qualify the use of a new steel alloy on an otherwise unchanged design, SN7.2 – likely built out of the same alloy – is instead focused on determining if SpaceX can begin trimming the margins of an increasingly mature technology.

Starship test tank SN7.0 and SN7.1. (NASASpaceflight – bocachicagal)
SN7.2. (NASASpaceflight – bocachicagal)

Curiously, SN7.2 is a sort of fusion of its predecessors: combining the stout stature of SN7.0 with SN7.1’s use of an aft thrust dome, but without SN7.1’s Starship-style skirt (the three rings at its bottom). Welded directly to its black test stand, it’s unclear why SpaceX chose to give SN7.2 a thrust dome, given that the thrust of Raptor engines can only be simulated with hydraulic rams if the tank is installed on one of two Starship launch mounts.

Regardless, whether SpaceX actually tests that aspect of SN7.2, the tank’s most important task is determining if future Starships (and perhaps Super Heavy boosters) can be built out of thinner, lighter steel rings. Its domes appear to be identical to past ships but writing on the exterior of the tank strongly implied that its three rings were built out of 3mm steel rather than the 4mm sheets that have made up every Starship built in the last 12 months.

SpaceX began loading the thin-skinned tank with liquid nitrogen (used to simulate cryogenic propellant without the risk of an explosion) around 9am CST and spent around three hours performing an “initial pressure test.” It’s unclear what that test entailed but it most likely involved raising the tank’s internal pressure to levels achieved by SN7.0 and SN7.1 Musk has previously said that that 6 bar was the bare minimum necessary for orbital flight, translating to 7.5-8.5 bar to achieve an industry-standard safety margin of 25-40%.

That SN7.2 survived that initial pressure test bodes well for the significant mass reductions SpaceX will need to optimize Starships for efficient orbital flight, potentially shaving 5-10 metric tons off the dry mass of future ships. For orbital rocket stages, every single kilogram of mass reduction translates to an extra kilogram of cargo capacity, whereas boost stages (i.e. Super Heavy) offer far more lenient ratios on the order to 10:1, meaning that adding 5-10 kilograms of rocket hardware reduces maximum payload capacity by just ~1 kg.

Depending on when SpaceX is allowed to launch Starship SN9, the company’s next test could involve pressurizing SN7.2 until it bursts, determining if the tank’s thinner skin substantially impacts its performance as a pressure vessel.

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SpaceX’s rideshare carried small satellite technology of interest to U.S. military

WASHINGTON — Among the 143 satellites that flew to orbit Jan. 24 on SpaceX’s record-breaking rideshare were technology demonstrations and payloads of interest to the U.S. military, including satellite components, in-space laser communications and remote sensing. 

Blue Canyon Technologies deployed  new satellite components it plans to incorporate in Defense Advanced Research Projects Agency satellites. Now owned by Raytheon, Blue Canyon is producing spacecraft for DARPA’s Blackjack low-Earth orbit constellation. The company’s CEO George Stafford said these new components include attitude control systems and reaction wheels intended to improve the performance of satellites. 

Other smallsats that flew on SpaceX’s Transporter-1 were laser communications payloads — known as optical inter-satellite links — that allow satellites to pass massive amounts of data to other satellites and to ground stations. Germany’s Tesat-Spacecom sent to orbit a laser communications terminal the company claims is the smallest in the industry, weighing less than a pound. 

Tesat-Spacecom spokesman Matthias Motzigemba told SpaceNews the company plans to test the optical communications payload for up to two years and conduct experiments aimed at building a global network of space and ground nodes. 

Motzigemba said he could not disclose the customers for these terminals but said Tesat currently supplies optical inter-satellite links to U.S. companies building low-Earth orbit constellations. 

The Pentagon’s Space Development Agency is especially interested in lightweight laser communications terminals for the fleet of LEO satellites it plans to deploy over the next few years. DARPA and SDA were hoping to launch two optical inter-satellite link cubesats on Transporter-1 but the satellites were accidentally damaged at the payload processing facility. 

SDA Director Derek Tournear commented in a social media post that losing those two satellites was “painful” and that Transporter-1 would have had 145 satellites on board if the two laser comms payloads had made it. 

SpaceX in this mission flew 10 of its own Starlink internet satellites equipped with laser links. The U.S. military plans to use Starlink to connect airplanes and other platforms, and optical inter-satellite links are preferred because they are more cyber secure than traditional radio-frequency communications.  

The largest share of smallsats in Transporter-1 were imaging satellites from Planet as well as radar imaging satellites from Capella Space and Iceye, and radio-frequency mapping satellites from HawkEye 360. These and other companies are expanding their fleets as the Pentagon and the intelligence community plan to increase use of commercial remote sensing services. 

Better technology needed for satellite tracking 

The U.S. military currently serves as space traffic controller. Space Command’s 18th Space Control Squadron monitors satellites and space debris for close approaches and posts their location on space-track.org. 

The unprecedented number of small satellites launched by SpaceX in a single flight is drawing attention to the challenges of managing space traffic as orbits become more congested. 

Satellite tracker and astrophysicist Jonathan McDowell said Transporter-1 included satellites from 24 different owners and operators, most from the United States and a handful from 10 other countries.

Concerns about spaceflight safety are creating opportunities for startups like Kayhan Space Corp., which developed cloud-based software to help military and commercial satellite operators plan maneuvers so they can avoid collisions. 

The company has received two Small Business Innovation Research contracts from the U.S. Air Force to support satellite tracking efforts.

“There is a lot of room for improvement in tracking of space objects,” Kayhan Space CEO and co-founder Siamak Hesar told SpaceNews. Today it is difficult to precisely establish the location of small objects like cubesats, he said. As rideshares become more frequent, said Hesar, the 18th Space Control Squadron and civilian organizations will need better tools to manage the congestion and avoid costly mishaps. 

SpaceNews

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SpaceX adds laser crosslinks to polar Starlink satellites

WASHINGTON — The first Starlink satellites launched to polar orbit are equipped with laser crosslinks, a technology the company plans to add to other satellites next year.

SpaceX included 10 Starlink satellites on its Transporter-1 dedicated rideshare launch Jan. 24. Those satellites are the first in the Starlink constellation SpaceX has deployed to polar orbit, after winning Federal Communications Commission to do so Jan. 8.

In tweets after the launch, Elon Musk, founder and chief executive of SpaceX, said those satellites were equipped with laser intersatellite links. “These also have laser links between the satellites, so no ground stations are needed over the poles,” he said in response to one tweet about the launch.

Intersatellite links allow satellites to transfer communications from one satellite to another, either in the same orbital plane or an adjacent plane. Such links allow operators to minimize the number of ground stations, since a ground station no longer needs to be in the same satellite footprint as user terminals, and extend coverage to remote areas where ground stations are not available. They can also decrease latency, since the number of hops between satellites and ground stations are reduced.

SpaceX has tested intersatellite links on other Starlink satellites, although they are not in widespread use. During a September 2020 webcast of a Starlink launch, the company said it tested “space lasers” between two satellites, relaying hundreds of gigabytes of data. “Once these space lasers are fully deployed, Starlink will be one of the fastest options available to transfer data around the world,” the company said at the time.

Musk, in another tweet, said SpaceX would roll out laser intersatellite links on other Starlink satellites next year. “All sats launched next year will have laser links. Only our polar sats have lasers this year & are v0.9,” he said.

SpaceNews

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aerospace astronomy News spacex Starship Super Heavy Top Story

SpaceX’s most important Super Heavy booster part makes first appearance

What is arguably the most complex and important part of SpaceX’s Super Heavy booster prototype has made its first appearance at the company’s South Texas Starship factory.

Following in the footsteps of Starship development, Super Heavy has been able to extensively borrow from the many lessons learned over the course of building, testing, flying, and building more Starship prototypes. SpaceX is able to use virtually identical materials, equipment, and techniques to build and assemble both Starship and Super Heavy propellant tank barrels and domes, while both stages will also share an extensive foundation of avionics, plumbing, propulsion, and ground systems, among other things.

In fact, lacking a conical nose, secondary (‘header’) propellant tanks, flaps, a reusable orbital-class heatshield, and vacuum-optimized Raptor engines, Super Heavy is actually substantially simpler than the Starships it will one day launch towards orbit. However, not everything is simpler. Super Heavy will ultimately be the largest and most powerful liquid-fueled rocket stage ever built or tested – power that demands as many as 28 Raptor engines and a thrust structure capable of feeding and withstanding them.

Designing, building, and testing such a thrust structure is arguably one of – if not the – most challenging engineering hurdle standing between SpaceX and its aspirational Super Heavy design. It’s the first of those Super Heavy-specific thrust structures – in the form of a tank dome – that was spotted at SpaceX’s Boca Chica, Texas Starship factory on January 25th, roughly six weeks after its main component was spotted.

Unlike Starship, which relies on a small central ‘thrust puck’ fit for three sea-level-optimized Raptor engines and plans for three larger vacuum-optimized engines that will attach to the side of its hull, Super Heavy’s current design iteration features as many as 28 sea-level Raptors. Aside from CEO Elon Musk revealing that Super Heavy would have a central cluster of eight engines, the precise configuration has been a mystery.

A look at Starship’s three-and-three thrust section configuration. (SpaceX)

The reality, as recently captured in photos above by NASASpaceflight photographers and contributors Mary (BocaChicaGal) and Jack Beyer, appears to be a much larger donut-shaped ring with space for eight gimballing Raptor engines. The remaining 20 Raptor engines would then be installed – possible mounted to the skirt, the thrust dome, or both – in the space left between the thrust donut and Super Heavy’s skirt.

Either way, the structures behind the two rings of engines will have to withstand at least 6600 metric tons (14.5 million lbf) of thrust at liftoff – approximately twice the thrust of Saturn V and Soviet N-1 rockets and more than three times the thrust of SpaceX’s own Falcon Heavy. Holding eight Raptors, the donut structure and dome recently pictured for the first time will also have to singlehandedly stand up to 1600 tons (3.5 million lbf; two Falcon 9s’ worth) of thrust while gravity, acceleration, and some 2500 tons of supercooled liquid oxygen push in the opposite direction.

Starship SN9’s standard thrust puck and dome. (NASASpaceflight – bocachicagal)
While seemingly identical from the ‘waist’ down, the first Super Heavy thrust dome obviously features a far larger Raptor engine ‘puck’ (donut?) at its base. (NASASpaceflight – bocachicagal)
Starship SN8 is slowly lowered onto Stand A, outfitted with a hydraulic ram used to simulate the mechanical stress of Raptor thrust. Super Heavy boosters will likely be tested in a similar manner, at first. (NASASpaceflight – bocachicagal)

In simpler terms, the business end of Super Heavy poses an extraordinarily difficult challenge and SpaceX has already built the first true-to-life prototype, with future iterations likely close on its heels. Much like Starship, if/when prototype booster number one (BN1) passes basic pressure and cryogenic proof tests, SpaceX will likely focus the rest of Super Heavy’s first test campaign on stressing the rocket’s unproven thrust structure to its design limits.

Like Starship, SpaceX will likely try to begin with nonexplosive methods, perhaps using a similar – but far larger – series of hydraulic rams to less riskily simulate the thrust of 8-28 Raptor engines. A steel structure spotted on a recent aerial overflight of SpaceX’s Starship factory might even fit the bill for such a structure, though only time will tell.

Based on an apparent acceleration of Super Heavy assembly work that may have started last week, as well as the crucial appearance of the last missing puzzle piece in the form of BN1’s thrust dome, the first booster could be completed and ready for testing sooner than later.

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