I make efforts to add to discussions instead of subtracting with negativity. Recently, I've broken my rule quite a few times, fretting over the future of general compute. I'd vowed to not break it again, but the discussion about Starship lacks a vital perspective.

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I don't understand the hype behind Starship. It's confusing to me. It is touching and nice; it's great to see people excited about space. However, the expectations and projections seem misaligned with reality. It seems that people are assuming that this is the vehicle itself, or at least an earlier version of it. That is likely to not be the case. This isn't anywhere close to the finished vehicle and several key technological problems remain. Yet, they've explicitly shaped it like the final version, and hyped it.

In certain ways, SpaceX seems to be leaning into the hype, leading to a gross mismatch between expectations and reality. For example, the current headline is inaccurate as the flight cannot be categorized as sub-orbital. The vehicle did not cross the Kármán line. These issues will detract from the meat of what has been achieved today.

SpaceX has achieved many milestones including demonstrating groundbreaking GNC (Guidance, Navigation and Control) capability today. Today's most impressive achievement is a high performant, stable Liquid-Methane engine. Prior investigations and projects found notable instability during ignition as well as low frequency instability. Another historical issue has been the need for a high pre-burner chamber pressure for a LCH4 engine.

These issues were mapped out via prior research. For e.g., in 2014, there was a NASA project that shares some heritage with Raptor, https://en.wikipedia.org/wiki/Project_Morpheus

> During the rest of March 2014 the ALHAT hardware was inserted again permitting a successful tethered test of the assembly on March 27, 2014. Tether Test 34 flight trajectory was similar to TT33 and TT29 with two hovers and a 3 m (9.8 ft) translation during a 3.25 m (10.7 ft) ascent.[97] Free Flight 10 (FF10) took place on April 2, 2014 with the ALHAT in open loop mode. The ALHAT imaged the Hazard Field and calculating navigation solutions in real time. Morpheus ascended to a maximum altitude of about 804 feet (245 m), then flew forward and downward initially at a 30-degree glideslope, then levelling out, covering a total of about 1334 feet (406.5 m) horizontally in 50 seconds while diverting to a landing site location 78 feet (23.8 m) from its initial target, before descending and landing on a dedicated landing pad at the front (south) of the ALHAT Hazard Field. The total flight time was ~96 sec, the longest flight to date.[98] Free Flight 11 on April 24, 2014 was a repeat of Free Flight 10 with some changes to the ALHAT.[99] April 30, 2014 Free Flight 12 was a repeat of FF10 but with the ALHAT choosing the landing location.[100]

The engine was designed for moon operation, and demonstrated dynamic hazard avoidance and translation to a previously unknown "safe" landing area. The technology has found its way to the Nova-C lander which is slated for 2021. https://en.wikipedia.org/wiki/Nova-C

NASA also has some fairly detailed technical reports on the subjects from earlier experimentation,

https://ntrs.nasa.gov/search.jsp?R=20100034924

and a comparative analysis of LCH4 and RP-1 for reusable boosters,

https://www.researchgate.net/profile/Holger_Burkhardt/public...

The key impressive element over here is a reusable, throttleable, stable LCH4/LOX engine that seems to be capable of reignition (at least in the atmosphere). This is a significant achievement and one that SpaceX should be lauded for. However, an engine does not a starship make.

A proper comparison would be the Space Transportation System, or the Shuttle. As Starship has Raptor, the Shuttle had the RS-25, a high efficiency, highly manoeuvrable and performant marvel of engineering. It is perhaps the only engine that could be re-used over a dozen times. A claim unmatched until the development of the past few blocks of Merlin engines. The STS also had superior GNC, for its time, and could autonomously land in flying brick mode all the way from orbit.

However, that wasn't enough. The real issue turned out to be the thermal protection system, operational temperature ranges and the cost of refurbishing these machines.

The STS may look like a bad bet right now, but if you were sitting in the 1970s, watching the RS-25 perform, seeing the GNC work, and watching NASA nail the first test flight with two humans on top in a single go, it would have seemed like the future.

However, much of what makes rocket science hard is in the details. And those details simply haven't been filled in yet for Starship. These hops are excellent tests, but once again, an engine and GNC do not a starship make.

In light of this, I am unable to understand the excitement for this vehicle. Several people assume that they're close to sending an orbital vehicle. Perhaps, but it wouldn't be reusable. And it would be quite mass inefficient for a one-way trip due to the construction techniques used.

Starship isn't anywhere close to the primetime. It's at least half-a-decade to a decade away from initial reusable testflights, and perhaps more given the under funding of the Artemis program. It is worth remembering that early on in SpaceX's history, Musk made a dummy rocket and took it to DC to convince politicians to help allocate COTS & CRS funding to SpaceX. His gambit succeeded. My personal perception and worry is that SpaceX is repeating the tactic at scale, creating a sense that they're further along than they are. This perception is mixed with a more dangerous one that the Starship is in a league of its own. It's not. Blue Origin's work and approach may be superior in the long run, as they're designing mission specific vehicles that are optimised to their context.

It is hard to convey to the public what realistic milestones look like in rocketry, but for context Raptor has been in development since 2009. The LCH4/LOX variant since 2012. It has taken nearly a decade to near the (limited) flight readiness stage. It is likely that the other components will take longer. I am worried that this early excitement will sour as the program takes longer than anticipated. The space program is highly dependent on public funding, there would be serious repercussions if public perception sours. I am worried about a rocketry winter.

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Edit. Re: Artemis & NASA

The Artemis program and other contracts now fund the bulk of Starship development. More broadly, NASA has poured billions into SpaceX and they're SpaceX's largest "investor" by far, except NASA doesn't take equity and treats it as "pre-funding" an eventual contract (which would also pay per launch).

Starship is (likely) to be mostly (up to 60% to 70% or so) NASA funded.

https://www.nasa.gov/press-release/nasa-names-companies-to-d...

https://twitter.com/SpaceX/status/1316417597257129985

https://twitter.com/SciGuySpace/status/1316421539521327109

Re: early SpaceX history and the dummy rocket.

http://www.spaceref.com/news/viewnews.html?id=903