Falcon Heavy prepares for debut flight as Musk urges caution on expectations | Hacker News Reader

Falcon Heavy prepares for debut flight as Musk urges caution on expectations

nasaspaceflight.com

24 pointsdeegles6 comments

A lot of this article is quoting Musk about how difficult the Falcon Heavy was, much more difficult than what they expected.

There's certainly no reason to doubt him when he says it was harder than expected, but I do find it interesting that the Delta IV Heavy [1] has an essentially identical configuration and has been operational since 2004. Maybe that rocket had similar difficulties, or maybe the large number of engines on Falcon Heavy make a real difference (each Delta IV has one large engine rather than 9 small ones).

I guess I'm surprised that Spacex was surprised about the difficulty.

[1] https://en.wikipedia.org/wiki/Delta_IV_Heavy

Also the fact that the boosters are reusable and expected to fly back to earth.

The number of engines being used in the FH, being much greater than Delta IV Heavy. The ignition process is complex for a setup and plumbing involved with that. And unknown interactions such as vibrations, etc. that they have yet to see from firing 27 engines at once as opposed to 9.

Also took the Delta Heavy team a long time before they could successfully launch commercial cargos, they had their own problems to overcome.

"The first launch of the Delta IV Heavy in 2004 carried a boilerplate payload (dummy payload), and failed to reach intended orbit. Cavitation in the liquid oxygen propellant lines caused shutdown of both boosters 8 seconds early, and the core engine 9 seconds early; this resulted in a lower staging velocity for which the second stage was unable to compensate. The payload was left in a lower than intended orbit.[6] Its first operational payload was the DSP-23 satellite, successfully launched in 2007; "

Interesting that Musk is often accused of hyping his projects, but here he's basically telling potential customers to be wary.

Whatever happens it will be interesting to watch and SpaceX does tend to learn and move on rapidly from it's mistakes.

Reply on news.ycombinator.com