5.08.2020

Starship SN5 recycling for a second attempt at 150-meter flight test

The Starship SN5 prototype is set to make a second attempt at a 150-meter test flight on Tuesday from SpaceX’s Boca Chica test site in Texas. Monday’s opening attempt was scrubbed after the Raptor SN27 engine aborted at ignition. The hop will be the first flight of a full-scale Starship tank section. If the hop is successful, it will clear the way for SpaceX to attempt higher altitude flights with Starship prototypes.

Tuesday’s livestream:

The launch window for Monday’s hop lasted from 8:00 a.m. to 8:00 p.m. Central (13:00 – 01:00 UTC). However, the hop was targeting liftoff during the later portion of the window.

Testing schedules are extremely fluid, with Elon Musk himself providing a countdown with about 30 minutes to go. This was followed by the T-10 minute police siren before counting down to ignition. However, the firing was aborted, likely at T-0, due to an issue with the Raptor.

The window on Tuesday opened at 8am local time.

As per usual, the first sign that the teams are working towards a hop attempt is when the road to the launch site is closed to the general public. This occurs well in advance of the test flight.

The pad is then cleared of all SpaceX personnel at least an hour or two before the hop. Finally, a siren is sounded ten minutes before the hop. The siren warns the residents at the nearby Boca Chica village that spaceflight activities are imminent.

To help you stay up-to-date on the flight’s status, updates will be posted on the @NASASpaceflight Twitter account. The NASASpaceflight YouTube channel is also broadcasting the test flight live from Boca Chica, Texas. The broadcasts begin once there are signs that SpaceX is set to make an attempt at the hop.

SpaceX has not performed a flight from their Boca Chica facility since Starhopper – a smaller-scale Starship test vehicle – hopped to 150 meters in August, 2019.

Starship SN5 features a thrust section with liquid oxygen and methane tanks stacked on top. A nose cone and aero surfaces are the only significant components missing between SN5 and a full-size Starship vehicle.

While SpaceX has not released the official height of SN5, it is estimated to be in the ballpark of 30 meters.

An off-centered Raptor engine mounted on SN4 via Elon Musk. SN5’s Raptor is mounted in the same fashion.

To perform the 150-meter hop, SN5 will use Raptor SN27. While SN5’s thrust section was built to support up to three Raptor engines in a triangle configuration, only one methane-fueled engine has been installed for the flight. This means that the thrust during the hop will be asymmetric. The asymmetric thrust will cause Starship SN5 to powerslide as it leaves the pad.

Attitude control thrusters will also assist with controlling the vehicle over the course of the hop.

Propellant loads will be low for the flight – reducing the risk to surrounding infrastructure in the event of an anomaly. 

A mass simulator has also been added to the top of the vehicle. Its presence is likely to compensate for the lack of propellant mass. The mass simulator was created by welding together two rolls of stainless steel. The rolls are of the same type used to construct the Starship prototypes. 

The profile of Starship SN5’s 150-meter hop will be very similar to that of Starhopper’s. SN5 will lift off from its launch stand and work its way up towards 150-meters. The vehicle will then begin to translate over to a nearby landing pad.

Six landing legs are located inside of SN5’s thrust section. They are folded up during launch and will deploy before landing.

Due to the prototype nature of the vehicle, there is a decent chance that Monday’s test flight could end with an anomaly. SpaceX’s development process leans heavily on rapid iteration. The company prefers to do tests like SN5’s hop sooner rather than later. The tests provide valuable data to inform future designs.

If SN5’s hop does not go to plan, Starship SN6 is already standing by, and could potentially be ready as a replacement for SN5 in short order. Thus, the recovery time from a potential anomaly would likely be determined by how long it would take to repair any damage to the launch site.

Of course, SpaceX will be hoping that the 150-meter hop goes to plan for SN5 like it did with Starhopper. Setbacks with previous Starship prototypes have delayed the 150-meter hop by several months.

Starships Mk1, SN1, and SN3 all failed cryogenic proof testing – where the tanks are pressurized with liquid nitrogen to ensure structural integrity. SN2’s testing was successful, but it was a smaller-scale tank prototype not intended for flight.

SN4 became the first full-scale vehicle to pass a cryogenic proof test and perform static fires. However, its fifth static fire resulted in an explosion shortly after engine shutdown.

SN4’s anomaly was caused by a problem with the quick disconnect umbilicals. As part of the test, the quick disconnects – which connect propellant lines to the vehicle – were detached as they would do for a hop. However, valves failed to shut, leaking large amounts of propellant. The propellant was eventually ignited, resulting in an explosion.

During SN5’s single static fire test, the quick disconnect system was once again tested. This time around, the system functioned as intended.

Common Dome Flip for SN8 – Via Mary (@bocachicagal) for NSF

If SN5’s flight attempt is successful, SpaceX will likely proceed to higher altitude test flights. While the exact details of the next testing milestones have not been confirmed, they are expected to feature a more fully-fledged Starship design.

Starship SN8 – the prototype which is currently under construction – is expected to feature three Raptor engines, a nose cone, and aero surfaces. These features would allow the vehicle to perform flight tests to much higher altitudes. However, plans are very fluid with Starship testing, so until SpaceX has had a chance to review the data from Starship SN5’s hop, future testing activities remain very much in flux.

Quelle: NASA Spaceflight

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Update: 19.00 MESZ

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SpaceX launches Starship prototype on dramatic test flight

After repeated delays for a variety of technical issues, SpaceX successfully launched a methane-powered prototype of its planned high-power Starship rocket on Tuesday. The company sent a dummy stage aloft from its south Texas test facility for a brief up-and-down hop to a nearby landing pad.

The test flight came just two days after a SpaceX Crew Dragon spacecraft brought two NASA astronauts safely back to Earth with a Gulf of Mexico splashdown after a near-flawless test flight expected to clear the way for operational missions later this year.

Resembling a giant metal grain silo, the Starship test rocket's single Raptor engine — powered by liquid oxygen and high-energy methane propellant — ignited at 7:57 p.m. ET, boosting the vehicle into the sky above Boca Chica, Texas, atop a plume of flaming exhaust and billowing clouds of smoke.

The planned maximum altitude was 150 meters (about 490 feet), but it was not immediately known how high the prototype actually flew.

Streamed by LabPadre SpaceX enthusiasts near the remote coastal launch site, the rocket's exhaust plume could be seen moving back and forth as its flight computer steered the vehicle to one side of the launch stand, setting up an apparently smooth landing on a nearby pad.

When the smoke cleared, the vehicle appeared none the worse for wear, a major milestone for SpaceX and the Starship rocket system the California company is designing for eventual missions to the moon and, eventually, Mars.

The red planet was clearly on SpaceX founder Elon Musk's mind after the rocket successfully landed.