LNG: TESLARATI

SpaceX announced during its CRS-18 Cargo Dragon webcast that the twice-flown orbital spacecraft will feature a handful of ceramic Starship heat shield tiles, meant to flight-test a critical component of the next-generation SpaceX spacecraft.

Extremely unfavorable weather forced SpaceX to scrub today’s scheduled CRS-18 launch around T-30 seconds to liftoff and tomorrow’s backup window (July 25th) doesn’t look any better. Nevertheless, whenever central Florida’s weather chooses to cooperate, the flight-proven Cargo Dragon capsule (C108) will be carrying a little piece of its successor along for the ride, a particularly fitting flight test given that the capsule will also become the first commercial spacecraft to launch to orbit three times.

Although Cargo Dragon’s reusability milestone is an undoubtedly impressive achievement, Starship must necessarily make the spacecraft’s third trip to orbit look like child’s play if it is to realize SpaceX’s dream of radically lowering the cost of spaceflight. To do so, Starship and Super Heavy will need to be the most easily reusable spacecraft and boosters ever built and flown by a nearly infinite margin, given that the ultimate goal is to require little more than careful inspections between suborbital booster launches and orbital Starship launches and reentries.

To accomplish that incredible feat, SpaceX will need to develop, test, and mass-produce thermal protection systems (including heat shields) that are more effective than anything that has flown in space. This is where Cargo Dragon (Dragon 1) and Crew Dragon come into play.

Although this Starship heat shield test comes as a surprise, it’s just a logical extrapolation of SpaceX’s tendency to flight-test hardware in retrospect. SpaceX’s routine and regular Cargo Dragon launches offer an obviously invaluable platform for the company to test new technologies both in orbit and reentry conditions. In fact, SpaceX is the only entity – government or commercial – with a reusable spacecraft capable of returning appreciable amounts of cargo from space to Earth’s surface.

If Cargo Dragon capsule C108 continues its successful record of orbital missions and recoveries, SpaceX will be able to recover Starship’s prototype ceramic heat shield tiles perfectly intact and thus have access to orbit- and reentry-tested hardware that should provide invaluable data for Starship. It’s unclear where exactly ceramic heat shielding would be used on Starship or if this means that the spacecraft’s transpirationally-cooled steel tiles did not pass muster, but CEO Elon Musk will hopefully provide additional details in a presentation later this month or early next.

Of note, the Starship heat shield test tiles appear to be installed near what is effectively the leading edge and thus the most stressed section of the heat shield. Ultimately, it’s extremely impressive that NASA has accepted this significant modification and concluded – alongside SpaceX – that the added risk of the prototype tiles is near-zero.

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Starhopper has completed its first untethered flight ever, simultaneously a small step for the awkward prototype and a giant leap for SpaceX’s Starship/Super Heavy program as the next-gen launch vehicle is carried into a new phase: flight testing.

Despite the spectacular and reportedly successful hover and divert test, Starhopper’s powerful Raptor engine appears to have started a significant fire, placing SpaceX’s Starhopper pad in a precarious position per the fire’s apparent adjacency to full liquid oxygen tanks. Ironically, despite Starhopper’s seeming predilection as of late towards catching itself on fire, the large rocket testbed appears to be entirely unscorched as a brush fire burns around a few hundred feet distant.

Despite several hours of delays likely caused by technical bugs in pad and vehicle hardware, SpaceX persevered and Starhopper ignited its Raptor engine and lifted off the ground – sans tethers – for the first time ever a few seconds before 10:45 pm CDT (8:45 pm PDT). Obscured on almost all fronts by a massive cloud of dust, steam, smoke, and fire, Starhopper was scarcely visible during the flight but appeared through the haze some 20 seconds after landing in a distinctly different location.

Per rough measurements, Starhopper appeared to reach an apogee roughly twice its height, which just so happens to translate to ~15-20m. Raptor clearly performed nominally, although SpaceX will undoubtedly be scouring through the data produced by the engine during its first-ever flight test.

According to Elon Musk, the SpaceX CEO will present an update on the company’s progress designing, building, and testing Starship and Super Heavy soon after Starhopper’s first successful flight, meaning it could potentially happen within the next week or two. Additionally, Musk deemed Starhopper’s July 25th flight a success and indicated that SpaceX would attempt to put Starhopper through a more ambitious 200m (650 ft) hop in a week or two, continuing what is expected to be an increasingly arduous serious of tests for the prototype.

Whether or not Starhopper makes it to that end of its increasingly difficult test regime, the low-fidelity prototype’s performance will lead directly into the first static fire and flight tests of what Musk deemed SpaceX’s “Mk 1” Starship prototypes, two of which are simultaneously under construction in Texas and Florida. Those Mk 1 flight tests could begin as early as September or October, barring any and all delays.

For the most part, Starhopper is more of a flying test stand for Raptor than a true Starship prototype, although the ungainly vehicle has undoubtedly proven that SpaceX is capable of building a flight-capable rocket out of steel – a first for the company.

At the moment, the aforementioned brush fire continues to burn around the apron of SpaceX’s spartan pad facilities. Thankfully, no propellant storage tanks appear to have been breached and the fire’s apparent adjacency to Starhopper’s pad just be an artifact of foreshortening. Stay tuned for updates on and photos of the test, as well as the post-test condition of Starhopper and post-fire condition of its launch pad.

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SpaceX has aborted Starhopper’s inaugural untethered flight test shortly after the planned T-0 liftoff time and is in the process of analyzing telemetry to see if another attempt is possible tonight.

At the planned T-0, Starhopper successfully ignited its single Raptor engine before quickly shutting down, at which point a fairly large fire began at a methane vent near the rocket’s domed top. Although the location was different, the fire was extremely reminiscent of a similar ‘fast-fire’ that occurred shortly after Starhopper’s dedicated July 16th static fire test, effectively engulfing the rocket in a fireball after unburnt methane was ignited.

Update (10:25 pm CDT): SpaceX has scrubbed Starhopper’s second hover test attempt of the day, pushing the test until at least Thursday, July 25th. Stay tuned for updates on the Starship testbed’s schedule.

Update (9:30 pm CDT): SpaceX is officially GO for a second hover test attempt.

Good news, SpaceX is GO for a second attempt at Starhopper’s inaugural untethered flight test, pending a flight-readiness poll of the vehicle’s test operators.https://t.co/rzZdEpLGuy

— TESLARATI (@Teslarati) July 25, 2019

Update: SpaceX is still holding out for a second hover test attempt tonight, pending data review and re-confirmed readiness from the test’s on-console operators.

Not yet officially scrubbed for the night. They are assessing if the recycle tonight or try another evening.

— Chris B – NSF (@NASASpaceflight) July 25, 2019

Above all else, it’s hard to emphasize how transparent SpaceX is being by publicly broadcasting what is effectively a developmental test for a rough rocket prototype – a test that could very easily end in some kind of failure. SpaceX kept the webcast live for a solid 15 minutes after the aborted hover test and minor vent fire but has since ended it and is reportedly analyzing whether another hover attempt can be made tonight (July 24th).

Most likely, the test will be scrubbed and another attempt will be made tomorrow after the vehicle has been detanked and technicians are able to inspect Starhopper for damage after a methane valve appeared to turn into a mighty impressive flamethrower.

Stayed tuned for updates from SpaceX, CEO Elon Musk, and other local observers. The aborted test can be watched at the link below.

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In the latest entry of SpaceX’s ever-changing Starship design process, CEO Elon Musk has indicated that the nominally reusable orbital spacecraft has moved away from a liquid-cooled steel heat shield to something slightly more traditional.

This information came as a SpaceX engineer announced during Cargo Dragon’s CRS-18 webcast that the twice-flown spacecraft would mark the first orbital test of a ceramic heat shield tile meant for use on Starship’s windward side. This major design change comes as a significant surprise and seems likely to either delay Starship’s orbital debut or hinder its ultimate reusability, although Musk just as recently claimed that the spacecraft could reach orbit for the first time less than six months from now.

Testing a possible Starship windward side ceramic tile. Maximizing emissivity is best for conductive/particle heating. Nice thing about steel is that tiles can be very thin, unlike carbon fiber or aluminum airframe.

— ln(e) (@elonmusk) July 25, 2019

Thin tiles on windward side of ship & nothing on leeward or anywhere on booster looks like lightest option

— ln(e) (@elonmusk) July 25, 2019

Back in late-2018 and early-2019, Musk took to Twitter to announce that SpaceX was pursuing an exotic metallic heat shield that would be cooled in large part by flowing liquid methane through tiny holes on its exterior, effectively ‘sweating’ away energy and preventing steel tiles from melting.

Despite incontrovertible evidence that SpaceX performed some amount of significant testing on the hexagonally-tiled steel heat shield concept, Musk’s July 24th tweets indicate that the liquid-cooled heat shield is unlikely to ever be used on Starship. For unknown reasons, SpaceX is instead pursuing some sort of thin ceramic heat shielding to protect the entirety of Starship’s windward side (i.e. the side facing the atmosphere during reentry). A handful of the first flight-qualified ceramic tiles – shaped for Dragon instead of Starship – will be tested on Cargo Dragon during the spacecraft’s orbital mission and eventual reentry.

Of note, this is not the only major design change Starship has undergone in just the last few months. Speaking on May 30th, Elon Musk stated that the design of Starship’s landing legs/fins and actuating wings and flaps has changed significantly since SpaceX revealed the new tripod fins + canard wings configuration in September 2018. According to Musk, that change will (or at least should) not significantly impact Starship’s schedule.

In fact, per his July 2019 claims that the first full-fidelity Starship prototype(s) could begin test flights in September/October and reach orbit as early as December/January, the Starship/Super Heavy schedule has actually radically sped up in the first half of 2019. In December 2018, Musk stated that he believed Starship had a 60% chance of reaching orbit in 2020, let alone late-2019.

For Starship, the massive spacecraft’s heat shield is arguably its single most important component. A failure to ensure that the heat shield is unprecedentedly reusable and reliable – even in the face of ultra-high-velocity interplanetary reentries – will severely limit Starship’s ability to achieve its ultimate goals of enabling affordable access to space and building a sustainable city on Mars. Musk’s comment that ceramic tiles are just “a possible” Starship heat shield element further indicates that SpaceX has yet to firmly settle on a heat shield design, let alone qualify said shield for orbital flight or kick off the mass-production necessary to completely cover multiple Starship halves.

Admittedly, there is still some good news in this unfortunate development. Most notably, the fact that Starship will still be made of steel means that the non-metallic heat shield tiles can be extremely thin and light, as they can be more or less directly attached to Starship’s steel hull. Additionally, steel Super Heavy boosters may be able to get away with zero heat shielding thanks to the relatively high melting point and heat resistance of certain varieties of stainless steel.

So long as both of those characteristics remain true, it’s likely that it will still make sense for Starship/Super Heavy to be built entirely out of steel instead of something like aluminum or carbon composite. With any luck, Elon Musk will provide a detailed update on the status of SpaceX’s next-generation launch vehicle soon after Starhopper survives its first untethered flight test.

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Update: Starhopper briefly ignited its single Raptor engine before a methane vent caught fire and the hover test was rapidly aborted. The prototype rocket does not appear to have left the ground, the fire is now out, and SpaceX is reportedly analyzing opportunities for another hover test attempt tonight (July 24th).

SpaceX’s Starhopper aborts first free flight after igniting Raptor engine, catching fire

According to updates from NASASpaceflight.com, SpaceX’s Starhopper prototype remains on track for a planned hover test debut later this evening (July 24th), set to become the first time the vehicle has flown in an untethered configuration.

Despite suffering a minor fireball on July 17th following a successful Raptor static fire test, Starhopper was quickly deemed to be unharmed and any minor damage suffered was easily repaired in a handful of days. Delayed from early to mid-July due to issues with Raptor SN05 that led to Raptor SN06 taking its place as the hover test engine of choice, SpaceX has nevertheless taken that and other hurdles in stride and is now ready for Starhopper’s first untethered flight test.

According to tireless Boca Chica local Mary (username BocaChicaGal), Starhopper fueling began around 6:10 pm Central Time (CDT), just a few minutes behind SpaceX’s nominal hover test schedule. Due to just how close local residents are to Starhopper’s launch pad, the actual act of propellant loading – enabled by strong pumps – is easily audible to residents and visitors of Boca Chica Village.

Assuming Starhopper operations are similar to Falcon 9 and Falcon Heavy, the unusual Starship testbed and prototype should be ready for its inaugural untethered flight, hover, and divert test sometime between 7 pm and 8 pm CDT (5-6 pm PDT). According to CEO Elon Musk, the test will be livestreamed by SpaceX itself, on top of an array of unofficial livestreams hosted by local residents and visitors.

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