First US Manned Launch Since 2011...Not Yet

On Wednesday, SpaceX and NASA planned the first launch from the USA of a manned spacecraft in nearly a decade (US-built, too). The last launch, in 2011, was the final flight of the Space Shuttle. It was back in 1981, when the shuttle first flew, that NASA last sent astronauts up on a new launch vehicle. That's almost 40 years ago. And, of course, it is the first time that it has been a private company's launch vehicle.

I'm sure it was in other places, but YouTube streamed everything live for several hours before launch on the SpaceX channel. Over 750,000 people were streaming it live. Kudos to YouTube since this is very different from the same number of people watching a movie, which can be uploaded to content delivery networks all over the country (or world). It takes a lot of scale to do that.

At one point, Elon Musk (who is CEO of both Tesla and SpaceX) was asked how he felt, having founded SpaceX in 2002, that here he was at the Kennedy Space Center at Cape Canaveral, with two astronauts having been driven to the launchpad in one of his car company's vehicles to be launched to the International Space Station on one of his rocket company's vehicles. He said he was pinching himself that it was true.

Like many people who are old enough and went on to careers in engineering (in the most general sense), I remember watching many of the launches of the Apollo program and, most dramatically, the moon landing of Apollo 11. It took place in the middle of the evening in Britain where I lived at the time. Since various parts of the Apollo program took place 50 years ago, there have been a number of 50-year anniversaries in the last year or so. I have used these as excuses to write about various aspects of space, rocketry, and the events of half-a-century ago. Wednesday's launch is another excuse—so here's today's post.

Space Posts

"If You Can Get Your Ship into Orbit, You're Halfway to Anywhere" This post covers the rocket equation, something I learned about first in undergraduate dynamics lectures where the professor (lecturer in UK terminology) showed in about five minutes why you can't get a single-stage rocket into orbit. The "tyranny of the rocket equation" means that it is very hard to get a vehicle into orbit (because you have to accelerate all the fuel initially) and as a result, you can only get about 4% of your launch weight fast enough to go into orbit. To put that in perspective, a can of soda weighs about 350g, and the empty can weighs 15g which is over 4%. So your budget to build a single-stage orbital spaceship would be less than Coke's budget to build a 330ml can, everything else being soda (for Coke) or fuel (for your rocket). The Launch America takes just 12 minutes from launch to orbit, and then 18 hours to rendezvous with the ISS.

The First Computer on the Moon. This post is about the 50th anniversary of the moon landing in 1969, with a special focus on the Apollo Guidance Computer (or AGC). In modern terminology, this computer:

ran at 0.001GHz with 0.000002GB memory and 0.000032GB of read-only storage. The display was a few dozen 1-bit pixels.

It was built out of just 4100 3-input NOR gates.

The Furthest Man Has Been from Earth. This post is about Apollo 13, the one that limped back to Earth after the explosion of an oxygen tank. Since it was the only spacecraft that went to the moon but never went into orbit, it went around the back of the moon at a higher altitude than the others (which slowed to enter orbit). Thus the three astronauts on board have been further from earth than anyone else.

What If It's Not 5G, But Satellites? This post takes a look at another of Elon Musk's space-related companies, Starlink. This has now launched 422 satellites (using SpaceX) out of a planned initial deployment of nearly 12,000. The downside of a satellite communication system is that you need a view of the sky like GPS. But unlike GPS, you need to be able to transmit, so it needs a much better radio channel. The upside is that 12,000 satellites are very cheap compared to millions and millions of basestations, and so (in a quote from the post):

Starlink will be competing with upwards of 600 cellular operators, 590 of which are sub-scale.

NASA: "Never Have Another Accident Due to Our Organizational Flaws" A keynote from the IRPS reliability conference by four-times-into-space astronaut Nancy Currie-Gregg. The presentation was about creating a "high-reliability organization", which turns out to be largely about culture. NASA (and its contractors) had plenty of scientists and engineers. But they used to have a management culture that didn't listen. Famously, an engineer called Allan McDonald refused to sign off on the Challenger launch over safety concerns about the temperature — but he was over-ridden.

Launch Escape System

Unlike previous craft, there is a launch escape system. From the time fuel starts to be loaded into the vehicle, until it reaches orbit (or until the fuel is offloaded in the event of a scrub), this system can pull the crew capsule off the main rocket. If it is on the ground, it splashes down in the Atlantic nearby. If it is already in flight, it will spash down below where it is deployed.

There was a January 19 test of the system when the craft was in the midst of ascent. There was (planned) premature MECO (main-engine cutoff). The crew capsule is pulled off ahead, the main Falcon9 breaks up and explodes (dramatically), and the capsule realigns itself, and eventually parachutes into the ocean and is recovered. Here is a video of the test, edited down (less than 2 minutes). Or you can see the full version (30 minutes, but start at 18 minutes for the launch, with the dramatic stuff happening a just couple of minutes later when the altitude is already about 10 miles).

Wednesday, May 27

The launch was scrubbed at T -17 minutes due to weather. There had been no technical issues. This was not entirely unexpected since they had forecast when the countdown started that the chance was only 60% that the weather would be good enough to pass all the criteria. The criteria that were exceeded were the electric field in the atmosphere, possible lightning, and anvil clouds. It was an "instantaneous launch window" so it could not be delayed. It either went as scheduled or the launch sequence was scrubbed. The earliest it could have been ready to go again was about an hour and a half later (after offloading and reloading with fuel) but that would not put them in an orbit to reach the ISS.

The first stage was already loaded with fuel. That had to be unloaded before it was safe to turn off the launch escape system and let ground personnel back into the area, and then the astronauts could disembark (disemcapsule?).

Saturday, May 30

The launch has been rescheduled for Saturday at 3:22pm EDT (12:22pm PDT). You should be able to watch on the YouTube channel for SpaceX, where it will be live from 11:00am EDT (8:00am PDT).

Since the chance of the weather being good is only 60% I decided to post this today, Friday, as both a recap of what happened on Wednesday, and as a preview to tomorrow's launch attempt. We will wait and see if everything goes on Saturday. If not, the next backup is Sunday May 31st at 3pm EDT (noon PDT).

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