Day: November 30, 2020

It had been anticipated that mid-November would see the 15km flight of  the SpaceX Starship prototype SN8.  As I’d reported last month, that vehicle had completed its initial static fire tests before going on to be fully stacked with the intermediate ring and forward nose cone with aerodynamic canards.

Speculation had been that the test flight could come around the time of the SpaceX / NASA Crew-1 mission for Crew Dragon to the International Space Station which lifted-off from Kennedy Space Centre on Sunday November 15th (see: Space Sunday: a Dragon, a telescope and a heavenly princess). However, a final static fire test of the three Raptor engines during the week leading up to the possible launch window saw an issue occur, prompting SpaceX to place all launch plans on hold until the issue had been investigated and resolved.

The was done during the week following the 15th, and SpaceX has set the first part of the week commencing Monday, November 23rd as the target time frame for that static fire test, which eventually came on Tuesday, November 24th, when all of the vehicles fuel tanks – main and “header” tanks (the latter required to provide fuel to the engines during descent) – pressured prior to a 3-second and successful simultaneous firing of all three main engines.

Currently, documents filed with the Federal Aviation Authority (FAA) show that SpaceX have requested further road closures around their Boca Chica, Texa, test facility starting on Monday, November 30th –  with Elon Musk indicating that this is likely to be the launch period for the vehicle.

The test flight itself is intended to test three core aspects of the vehicle’s flight envelope:

• Powered ascent to altitude.
• Controlled “belly flop” decent whilst horizontal, utilising the fore and aft flps to maintain stability and rate of descent.
• Orientation to vertical during the final 100 metres or so, and descent to a tail-first landing under engine propulsion.

The flight comes with a high degree of risk – nothing quite like it has ever been attempted before – and SpaceX are anticipating only around a 33% chance of success, and that SN8 will in fact be lost in what they euphemistically refer to as an “unscheduled disassembly of the vehicle”.

However, Starship prototype SN9 is almost ready to start ground tests, and SN10 is following up behind it, meaning that if SN8 is lost, flight testing shouldn’t suffer too much of an interruption, and if the initial 15 km flight is successful, then SN9 and SN10 will be available to extend the testing programme such as flying to higher altitudes and / or flying with a full fuel load – SN8 will fly with its tanks carrying only the fuel to get to 15 km and then make a (hopefully) safe return and landing.

At the same time as work is continuing on the starship prototypes, SpaceX has also been engaged on the development of the test launch platform for the Super Heavy Booster and the assembly of components for what will be the first of these boosters, called simply BN1. Also appearing at the site is a mock-up of a section of the “lunar starship”, the vehicle SpaceX has put forward to help NASA in its plans to return humans to the Moon.

In terms of the Super Heavy booster, SpaceX appear to be reconsidering the idea of trying to bring such a massive beast back to Earth to land directly on the launch platform. While this would allow the company a shot at its so-called “fast turn-around” of the vehicle between launches, it also requires a high degree of pin-point accuracy on landing, and opens the launch mount to the risk of damage should any go awry with a returning booster. In a recent tweet on the subject, Musk indicated that the initial Super Heavy booster flights will aim to land the vehicles on the concrete apron alongside of the Boca Chica launch mount.

But  it is not all good news for SpaceX, as the company has been informed it must undergo a new FAA environmental  review and re-licensing specifically for the launch of the Super Heavy vehicles.

This is because at the time the original environment review took place in 2014, the license granted was for test flights of the Falcon 9 and Falcon Heavy, not the Starship or Super Heavy. The FAA allowed flight testing of the former to occur at the site, as it was deemed to pose no greater impact than flight testing either of the booster systems. However, with some 30 Raptor rocket motors powering it, the super Heavy is a significantly different proposition, particularly as SpaceX now intend to use Boca Chica not just as their test facility, but an operational launch facility – a move which has angered local environmental groups.

They went from proposing a few launches per year of an already field-tested rocket to ongoing experimentation of untested technology without doing the studies that would ensure environmental protection and public safety and without giving the local community a chance to have a say.

– Jim Chapman, president of Friends of the Wildlife Corridor

This has resulted in significant pressure on the FAA to carry out a new full review, called an Environmental Impact Statement (EIS), which could take up to two years to complete (from initial assessment through to drafting the report to debate and final report). Currently, it is not clear what impact this will have on the company’s plans for Super Heavy test flights.

Continue reading “Space Sunday: ups and downs, and returns” →