Apollo 11 — when tech needed innovation and a bit of piloting

By today’s standards, the landing by humans on the Moon was technologically primitive.

Keep in mind, the Apollo 11 mission happened before the Internet; in fact, the first two nodes of the ARPAnet, from which the Internet sprung, wouldn’t be connected until several months later. Apollo is credited with pushing micro-miniaturization of electronics. Without it, the Apollo Guidance Computer would not have been possible, or at least weighed many times more than it did. This machine, which aided the landing of the Eagle lunar module on the Moon, had 2048 words of memory, each word being 16 bits long. It had a clock speed at 2.048 MHz, about 1/500th to 1/1000th of current smartphones, which may have multiple processors at 1 to 2 GHz.

In the end, the computer was overloaded, and pilot Neil Armstrong took over to make a landing under manual control with read-out assistance from astrodynamicist Edwin “Buzz” Aldrin. (The computer did not die; it was over-saturated with computation tasks, but continued to function.)

The landers that preceded Apollo to the Moon did not have digital computers.  The Surveyor series of landers had servos, which fed back to various spacecraft systems, resulting in soft landings.

Apollo Guidance Computer and display/keypad

Apollo Guidance Computer and display/keypad

Engineering design was dominated by drafting boards; computer graphics was in its primitive developmental stages, and along with it, interactive CAD of mechanical parts was barely beginning. The NASA STRuctual ANalysis program (NASTRAN) was under development during this time, finally being released to NASA in 1968, after the Saturn V was designed.

On the other hand, some things haven’t changed much. There is no miniaturization of a human crew. They need a certain amount of consumables, which must be stored for the trip. Rocket engines still use chemical propulsion. LOX/RP-1 (liquid oxygen and refined kerosene), the propellant combination used by the Saturn V first stage, is still a mainstay of launch vehicle design. The efficiency of translating chemicals into F=MA (or really F=v*dm/dt) has not appreciably changed.

And yet, with all the technology constraints and unchanging laws of physics, American primitive technology and ingenuity got humans to the surface of the Moon, and brought them safely back to Earth.  … And yet, 45 years later …..

That first landing did not go completely according to plan. Armstrong had to take over, with Aldrin’s assistance. Armstrong was under pressure to pick a safe spot quickly (which the automatic systems had not done), and put the craft down. By the time it landed, the Eagle had about 15-20 seconds of fuel left. Mission Control in Houston very likely had a sinking feeling that this could end badly; hence the comment about “a bunch of guys about to turn blue. We’re breathing again. Thanks a lot.”

A re-enactment of the landing, based on radio transmissions, transcripts, and video, shows just how close they were to ending in disaster. (Kudos to Thamtech, LLC, for assembling the site together a couple of years ago.)

T + 45 years — the view from the pad

Sunday, July 20, marks the 45th anniversary of the Eagle landing at Tranquility Base on the Moon.

That journey started on July 16, 1969, with the launch of Apollo 11 from Launch Complex 39 (specfically Pad 39A) at Kennedy Space Center, Merritt Island, FL. The Saturn V rocket, with three stages and the Apollo spacecraft on top, stood 111 meters (363 feet) tall. The first stage tank had a diameter of 10.1 meters (33 feet).

It weighed 2950 metric tons (6.5 million lbm), and was lifted off the pad by 34 MN (meganewtons, 7.6 million lbf). The result is that it lifted off the pad relatively slowly. With a thrust-to-weight (T/W) ratio of 1.17, its acceleration off the pad was 1.66 m/s2 (5.45 ft/s2). (Recall that Earth’s surface gravity is 9.807 m/s2 (32.17 ft/s2).

As a result, compared to many other rockets, including the Space Shuttle, it feels a bit like slow motion. To that, add cameras that capture the launch at 500 frames per second (fps), and then play that back at a normal frame rate. The result is slowing down the motion by a factor of 16 to 20 (for 30 to 24 fps respectively). At this rate, you get to appreciate in detail the tremendous forces at play here.

Mark Gray, executive producer for Spacecraft Films, provided commentary for this clip of the launch at 500 fps. Posted five years ago, it gives amazing insight into the engineering that went into the pad, and the kind of forces at play when a Saturn V was ignited and lifted off.

In later decades, Pad 39A would see the launch of many Space Shuttle missions. In April 2014, the pad was leased to SpaceX, which is modifying it to support Falcon 9 v1.1 and Falcon Heavy launches.

And if you’re trying to find it, here it is.

Design-challenged

With due respect to the “challenged” individuals who have impediments or roadblocks to performing certain tasks… some days, I feel like I am design-challenged. I may have a fair amount of understanding about a particular design goal and how it might be realized, but I can’t do the design.

To clarify, I operate in a couple of technical domains.  I’m doing fine in one (computer systems, especially computer software). But in the other, I have a sense of extreme frustration. Basically, I can’t do aerospace vehicle design.

I’ve come to the conclusion that to do reasonable design work, you need the appropriate 3D mechanical CAD tools, combined with simulation capability, such as static structural analysis, fluid flow, and thermal conductivity. Back of the envelope computation doesn’t cut it for a design that can be built.

What’s the problem with the CAD tools? They cost on the order of $7,000 for CAD and simulation capability. An aspiring designer cannot afford these tools. (This is not the same as having AutoCAD or Sketch-Up for drafting and design.) From here, the CAD system may generate instructions for manufacturing. In fact, for a more coordinated environment of design tools, database, and interface to manufacturing, the software tools may cost $50,000.

These tools are part of a design workflow. Other components of the workflow might include trajectory design and analysis, high fidelity CFD, design of the fuel system. For a vehicle design to work, the different parts of the workflow need to be able to talk to each other. That is, there are data formats and possibly signals agreed upon between tools.

All this introduces a set of workflow challenges. That is, the design-challenged individual may also be workflow-challenged.

To better size up the problem for a small aerospace entrepreneur, I’m hosting a session on “Aerospace Workflow Challenges” at the Hacker Dojo on June 29. I have more notes on the expectations of the session here.

 

A text-based countdown script in Python

Problem: You want to count down to an event (e.g., a rocket launch). But the web-based animated countdown consumes too much screen space and battery power (i.e., your laptop’s fan turns on when you go to that web page).

Solution: a text-based countdown in a small shell or console window. This one, down.py, is written in Python 3. The project on GitHub is called DownPy.

I’ve tested this on Linux (Ubuntu 12.04) and Mac OS X Mavericks (10.9). It has no fancy appearance, and all it does is count down.  But that’s also why it barely takes any power.

If you want to try this in the next few days, here is an example.  This the command for counting down to the currently scheduled launch time of NASA’s Orbiting Carbon Observatory (OCO-2).

./down.py 2014-07-01 02:56 -z -7:00

If you’re a git user, then you should know how to clone the DownPy project. And if you aren’t, there is really only a single file. Make sure you have Python 3, copy the file, make it executable, and go for it!  Of course, you can also open multiple shell/command windows, and have a countdown for each different event you are interested in. (There are some Mars spacecraft encounters coming up.)

So now you how I spent one day of my weekend.  I came up with the basic date/time queries in Python earlier in the week. Then on the weekend, I created a loop that adjusts to lag and other compute load oddities.  By the evening, I had it reporting and rewriting on a single, non-scrolling line.

[More info on Python, including downloads.]

SpaceX Dragon V2

SpaceX unveiled the manned version of the Dragon capsule on Thursday evening, May 29. (Yes, about 2 weeks ago. [I've been busy.]) If you missed it, here is how SpaceX described Dragon V2.

The essentials

Judging from Internet reaction, people seem to be enamoured with it. You can read reactions to it elsewhere.  I’ll give you my impression.

  • The SuperDraco engines, which are used for landing the capsule on solid ground, are also the emergency launch escape system.  Unlike Mercury, Gemini, and Apollo, where the escape tower was jettisoned at altitude after launch, the SuperDraco engines are integral to the spacecraft.  The placement of the engines dictated an altered shape for the capsule. They are presumably evolved from the Draco thrusters used for attitude control, but are 100 times more powerful. (As Elon said, “Hence, the ‘Super’.)
  • The large touch-screen panel, which can stowed away, is new to spacecraft design.  This indicates that the actual avionics which provide data to the display, are located elsewhere in the capsule — a major departure from previous manned spacecraft and aircraft design. I saw some comments that compared it to a Tesla touch-screen display.  I can believe that Tesla might produce some custom components for SpaceX; there is certainly technology sharing going on.  To me, the joystick looks like it could have been designed for a sports car.

Dragon V2 Interior

This is, in my judgement, an incomplete spacecraft, but a really impressive one.  The design is probably complete, but what was on display was a basic functional shell.  It looks roomy because there weren’t seven people in there, and the storage compartments for food and other crew consumables have not been installed yet. (Oxygen and water are likely provided by tanks on the perimeter out the capsule, but outside the cabin.) Presumably, the crew would spend some time in a shirt-sleeve environment rather than in helmeted pressure suits.  There will need to be space to stow suit gear away.

Avionics

Not on display were the avionics and software for how to do a propulsive soft landing on ground. It stands to reason that SpaceX has an ambitious avionics and software program that encompasses real-time attitude dynamics and engine control. SpaceX has been doing landing tests with Grasshopper and Falcon V9R. Now it will add Dragon V2 to that effort.

A lander for Mars?

SpaceX designs most of its hardware with Mars in mind.  It is possible that this fundamental Dragon capsule design could be what lands on Mars.  There are, however, a couple caveats.

  1. The capsule would have to open up to the Martian atmosphere, de-pressurizing to vastly different conditions from what are inside the capsule upon landing.  Martian atmospheric pressure is about 1/100th of Earth sea level. The temperature radically colder than Earth, perhaps comparable in some cases to Antarctica.
  2. If the capsule is to be reusable on Mars, it probably is going to be powered by methane rather than the current hypergolic propellant. Methane can be produced on Mars. Other consumables would have to be produced as well.  That is, there needs to be a ground infrastructure for servicing a capsule before it could be reused.

In the final analysis

This is a low-Earth orbit vehicle for ferrying passengers to station such as the ISS or perhaps a Bigelow station, maintain a crew for at most a few days.  With few crew members, it could stay in orbit for a longer time.

It is a stepping stone in developing technology for Mars, not the final vehicle, but it is a fairly major one. A launch escape test later this year will demonstrate the SuperDraco engines and avionics in flight.


Footnote: Rick’s been busy

For those who wonder, what happened, why did I drop out of sight?, the answer is, I’ve been busy.

Outside of the day job, I’ve been helping coordinate activities on behalf of the Silicon Valley Space Center.  Specifically, we just completed a Space Entrepreneurship Series, a sequence of four meetings for aspiring space entrepreneurs. We consistently had 20+ attendees. Hopefully, this means a bumper crop of new space enterprises in the next year.

My day job is in the software group of a computing hardware design company. Sometimes, I get intriguing challenges, some of which call for really long days just because I can’t stop. The last few weeks have been like that.

To make life more interesting, a couple of space-related efforts I have helped on seem to have attracted attention.  More on those later.

Falcon 9 soft landing video – work in progress

F9-waterlanding-2014-0418-partial-reconstruct-frame By releasing the raw MPEG stream of the April 18 water landing of the Falcon 9, SpaceX asked for assistance from computing video imaging hacker/expert community to restore stream.  It had been plagued by choppy transmission through bad weather conditions.

Now, the hackers/experts have a partially restored result.  The sequence begins just before ignition of the engine, and continues as the exhaust plume hits the water.  Throughout the landing sequence, the legs are already deployed.

The next landing sequence test should occur after the next launch.  A Falcon 9 is expected to launch an ORBCOMM OG2 satellite into low Earth orbit.  This launch was originally scheduled for May 10, but was scrubbed due to problems with static fire tests on May 8 and 9.  The earliest launch opportunity at the busy Cape Canaveral is June 11.

More info:

KickSat race to deploy

[Note: This article was originally published in the May 5 edition of the RocketSciRick Update. KickSat unfortunately was not able to deploy its sprites before re-entering the Earth's atmosphere on May 14.]

kicksat_spriteAlthough KickSat was successfully deployed into orbit during the SpaceX CRS-3 launchon April 18, 2014, a glitch happened on the satellite. A hard reset that affects the master clock happened on the morning of Wednesday, April 30. Since other parts of the satellite seem to be operating normally, the likely cause is some form of space radiation.

From the time the clock starts, it counts 16 days to deployment of the 104 sprite spacecraft that KickSat houses. If the reset had not happened, deployment would have happened on May 4. However, with the reset, the date was moved back to May 16.

“Unfortunately,” says project lead Zac Manchester, “it looks like KickSat will most likely reenter and burn up before the 16th. We’ve spent the last couple of days here at Cornell trying to think of every possible contingency, but it seems there aren’t very many options right now. KickSat’s uplink radio, which we could use to command the deployment, can’t turn on unless the batteries reach 8 volts, and it doesn’t look like they’ll reach that level in time.”

There is a small chance that the batteries will recharge before then or KickSat might survive beyond May 16. For now, it is still alive, and ham radio operators are still reporting packets to the KickSat Ground Station in Google Groups.

More info on KickSat: