Space Sunday: crashes, tests and an Inspiration

Two seconds from disaster: an inverted Starship prototype SN9 about to impact the landing pad at Boca Chica, February 2nd,2021. Directly below the vehicle and on the horizon is the angled base of the Super Heavy launch platform (under construction). Centred on the ground is the Starhopper test vehicle with the SN7.2 test tank to the right. Image credit: Cosmic Perspective

On Tuesday, February 2nd, and after Federal Aviation Authority (FAA) related delays, SpaceX Starship prototype SN9 took to the skies over southern Texas in the second high altitude flight test for the Starship programme.

The flight itself, to some 10 km altitude, followed by a skydive descent to around the 2 km altitude mark, was remarkably successfully – as was the case with the first high-altitude flight (to 12 km on that occasion) seen with Starship prototype SN8 in December 2020 (see: Space Sunday: the flight of SN8 and a round-up). However, and also like the SN8 flight, things went off-kilter during the final element of the flight, resulting in a complete loss of the vehicle.

Lift-off: SN9 rises from its launch platform with SN10 beyond it. he angle of this shot makes the two vehicles appear closer than they were in reality; SN10 was in fact well clear of its sister. Image credit: LabPadre

As I’ve previously noted, the route of Staship prototype SN9 from fabrication high bay to launch stand had been remarkably fast compared to that of SN8, leading to speculation that the anticipated second flight test could occur in January. However, while the vehicle remained on the launch stand going through numerous pre-flight tests, including numerous Raptor engine re-start tests (which actually saw two of the motors swapped-out), things appeared stalled before that final step of an actual flight.

This now appears to be down to the fact that the FAA weren’t entirely happy with SpaceX over the flight of SN8, which effectively went ahead without proper approval. In short, SpaceX applied for a waiver against the licence the FAA had granted for Starship flight testing which would have allowed the company to exceed “maximum public risk as allowed by federal  safety regulations”.

At the time, the waiver was denied – but the SN8 launch went ahead, violating the required safety limits, and whilst no-one was injured in the crash of SN8, the FAA correctly ordered a full investigation into the flight and also the safety culture and management oversight of SpaceX operations. Those investigations not only took time to complete, but also afterwards required FAA review and modifications made to the licence granted to SpaceX to carry out Starship prototype flights.

Boca Chica from space: captured by a SkySat satellite approximately 568 km above the Earth, this image shows the SpaceX Boca Chica launch facility with the two Starship prototypes on their launch stands, the SN7.2 tank test unit, the Super Heavy booster launch stand under construction, and other elements such as the fuel farm, and Highway 4 running from the coast (r) back to the SpaceX construction and fabrication facilities (off to the left of the image). Image credit: Planet Labs
If a licensee violates the terms of their launch license, they did so knowing that an uninvolved member of the public could have been hurt or killed. That is not exaggeration. They took a calculated risk with your life and property … If the FAA does not enforce their launch licenses, it will damage the long-term viability of the launch industry and damage their credibility with Congress. It is possible that the industry could suffer significant regulatory burdens enforced by Congress to ensure safety.

– Former deputy chief of staff and senior FAA adviser Jared Zambrano-Stout,
commenting on SpaceX launching SN8 without the request licence waiver

The required licence modifications were not completed until February 1st, the day on which SpaceX initially attempted to launch SN9, and their lack of their availability may have been the reason that attempt was scrubbed, resulting in the February 2nd attempt.

Coverage of the test flight started very early on the morning (local time) on February 2nd, with SpaceX providing multiple camera points around the launch stand and on the vehicle, as well as via drones.flying overhead In addition, space flght enthusiast such as NASASpaceflight.com also provided coverage from multiple points around the Boca Chica, Texas, site, including video recorded by Mary “BocaChicaGirl”, who provides a daily 24/7 feed of activity at the site.

The vehicle, with prototype SN10 occupying a second launch stand nearby, lifted-off at 20:25:15 UTC, following the ignition of all three Raptor engines. The launch was delayed by some 25 minutes as a result of a range safety violation – one of the circumstances of concern to the FAA. However, the ascent itself was flawless, with the vehicle rapidly climbing to altitude over the next four minutes, two of the Raptors shutting down as it did so to reduce the dynamic stresses on the vehicle in light of it being only partially fuelled and to ensure it didn’t overshoot the planned apogee for the flight.

Flip over: at 10 km altitude, the one operational Raptor motor gimbals its thrust as the leeward midships RCS thruster fires, tipping SN9 over to start its 2-minute skydive back to the ground. Image credit: SpaceX

This came at 20:29:15 UTC, with the vehicle entering a brief hover using its one firing motor, as fuel supplies were switched from the main tanks to the smaller “header” tanks that would be used to power the engines during landing manoeuvres. At this point, the remaining motor shut down as the reaction control  system (RCS) thrusters fired, gently pushing the vehicle over from vertical and into its skydive position, where the fore and aft aerodynamic surfaces could be used to stabilise the vehicle during descent.

This phase of the descent lasted just over 2 minutes, with the order given to re-start two of the Raptor engines given at 20:31:35 UTC. These engines should have then gimballed and used their thrust, together with the forward RCS thrusters to return the vehicle to a vertical pose before one of the motors again shut down and the second slowed the vehicle into a propulsive, tail-first landing.

From below: a camera on the ground dramatically captures the moment one of the Raptor engines on SN9 re-starts as RCS systems fire to help maintain stability. Image credit: SpaceX

Both of these motors fire a split second apart, and footage of the rear of the vehicle suggests that the first may have suffered a mis-fire before starting correctly. However, the second motor appears to have suffered a catastrophic failure on re-start, possibly involving a turbopump failure: as it ignited, debris could clearly be seen being blown clear of the vehicle.

With only one operational main engine, SN9 was unable to stop its change in flight profile and remain upright. Instead, it continued to rotate and become inverted just before it struck the landing pad in what SpaceX refer to as “an energetic, rapid unscheduled disassembly” (that’s “exploded on impact” for the rest of us).

No official word on the failure has been given – obviously, SpaceX will need time for a thorough investigation, and will likely have the FAA watching closely. It is also not clear if the material coming away from the vehicle is actually parts of the engine, or sections of the engine skirt blown clear of the vehicle. As some are still to be drifting down to the ground fairly close to SN10 on its launch stand, it is possible they are from the vehicle’s skin.

A wider image of the inverted SN9 prototype just before impact, with the Super Heavy launch stand, SN7.2 tank and Starhopper prototype overlapping one another, and the SN10 prototype to the right. Note the debris (arrowed) drifting down behind the vehicle. Image credit: NasaSpaceflight.com

Continue reading “Space Sunday: crashes, tests and an Inspiration”

A return to Where our journey in Second Life

Where Our Journey Begins, February 2021

Where Our Journey Begins is a homestead region held and designed by Vivian Ewing. It’s a place we first visited fairly recently – in September 2020, in fact. However, after getting several nudges from people that the region has been redressed for the coming Spring, I suggested to Caitlyn that we hop over and take another look.

The changes made since that first visit of ours are extensive; yet at the same time, there is much about the setting that does offer a sense of continuation from that iteration to this: the curtain wall of cliffs with their waterfalls (now to the south-east of the region, rather than to the north), the use of granite-like tables of rock on which to site some of the region’s buildings, etc. This mix gives the region a pleasing sense of the familiar couple with discovery.

Where Our Journey Begins, February 2021

The land itself also offers a reminder of the former build: a large arc of land sweeping from the north-east and round to the south-west, those high falls dropping from its eastern face into a large pool of water. This in turn splits the lowlands by means of two streams that flow west and north respectively, trapping a wedge of land between them. And just off the shoreline of this wedge is a small circular island that serves as the landing point for visitors, connected as it is to the rest of the region by an ageing wooden bridge.

Across the bridge, and under the shade of ginkgo biloba and cherry blossom trees, and the turns of gulls circling above them, a track offers a choice of direction across the land, with the shorter arm directing visitors to where a path winds up the table of rock occupying the centre of this island, the longer offering a path around its base.

Where Our Journey Begins, February 2021

Which of these you take is entirely up to you. If you want to avoid getting your feet wet, then the path up to the top of the squat plateau is the best means of reaching the north-eastern “headland”, going by way of two high bridges. The first of these spans the gorge between the first plateau on the island and the second, home to a small summer house  and with a much longer rope-and-wood bridge extending across the broad valley of the stream below to reach the north-east uplands.

The latter are home to a flat-topped house with flat-topped / adobe walls and an external stairway leading to the upper floor. Hemmed by trees and shrubs, it looks west towards the sea, the region’s lighthouse just visible through the foliage of two aged and gnarled trees standing guard over a garden swing. Sitting at the foot of one of these trees, and marked by a large urn, is an overgrown path that leads down, somewhat precipitously, to a small sheltered beach.

Where Our Journey Begins, February 2021

This is actually one of two beaches within the setting, the other being off to the west, reached via the second arm of the track leading away from the landing point’s bridge. steps down from this arm of the track point the way to it by way of a farm small holding with water tower, shed, tractor and livestock. Bracketing the track on its other side from the steps is a old paved area the marks the entrance to the gorge between the two humps of the island’s plateaus. It  is home to a ice cream stall and outdoor seating – although those wishing for a little refreshment will have to wait in line behind the little girl who is passing on her order!

Beyond this, the track ends at a low flight of steps and a choice of routes: either across a little arched bridge crossing the second of the region’s streams, or continuing eastwards to under the broad shade of great oak trees.

Where Our Journey Begins, February 2021

A chapel and open, grassy space lie across the bridge, a pastor waiting within the chapel to conduct wedding services for L$300, the space outside being suitable for the after-service photographs. Off to the east and beyond the oak trees, there sits a caravan that looks to have been converted into a more permanent residence, complete with creature comforts such as satellite TV and a curtained deck overlooking the region’s pool and waterfalls. Like the house up on the uplands, it is unfurnished, so you’ll have to let your imagination fill in the details.

Throughout the setting are numerous touches of detail that make it ideal for photography, and a good number of places to sit and pass the time. Good use is made of EEP settings to produce a unique ambient environment,  complete with rainbow for those prepared to play with the Sun position via Personal Lighting. Admittedly, the colours of the rainbow will be inverted thanks to a rendering bug (unless you are using the latest Love Me Render viewer from the Lab}, but the LMR 5 viewer does mean a fix for this issue should be filtering through to all viewers in due cause.

Where Our Journey Begins, February 2021

Overall, Where our Journey Begins remains a pleasing visit with more than enough to engage the Second life tourist.

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