To the Moon!

Iterative / Incremental delivery to get to the Moon.

During a recent trip to Houston, Texas I was fortunate enough to visit the NASA Johnson Space Centre. The Apollo program was designed to land humans on the Moon and bring them safely back to Earth.  I believe this achievement to be one of the greatest engineering feats in history but it had never dawned on me to think about how it was achieved.  It was while I was visiting NASA that I realized that Apollo Missions 7,8,9,10 and 11 were used iteratively and incrementally to achieve this goal.  The list of problems necessary to be solved to achieve the ultimate goal might have looked (simplistically) something like this:

  • Leave the Earth’s atmosphere
  • Enter Earth orbit
  • Orbit the Earth
  • Travel to the Moon
  • Enter Moon orbit
  • Orbit the Moon
  • Land on the Moon
  • Re-enter an orbit of the Moon
  • Travel to the Earth
  • Orbit the Earth
  • Land on the Earth

 Each of these problems had sub-problems associated with them and in software development we might associate these with Epics and their composite Stories.  Also note that extensive future mission improvements were made by using retrospectives after each mission.  I’ve highlighted the Epic/Stories addressed during each mission and I have extracted the descriptions of each mission from: http://www.nasa.gov/mission_pages/apollo/missions/

As you’ll see the problems were solved iteratively and incrementally until the only problem left to solve was the actual landing on the lunar surface.

Apollo 7

  • Leave the Earth’s atmosphere
  • Orbit the Earth
  • Travel to the Moon
    • Mid-course corrections
  • Orbit the Moon
    • Communications on the far side of the moon
    • Undock LM from CSM (simulation)
  • Land on the Moon
    • LM descent
    • LM land
  • Re-enter an orbit of the Moon
    • LM ascent
    • Dock LM to CSM (simulation)
  • Travel to the Earth
  • Orbit the Earth
  • Land on the Earth

The primary objectives for the Apollo 7 engineering test flight were simple: Demonstrate command and service module (or CSM) and crew performance; demonstrate crew, space vehicle and mission support facilities performance during a crewed CSM mission; and demonstrate CSM rendezvous capability.

The S-IVB stayed with the CSM for about 1 1/2 orbits, then separated. Schirra fired the CSM's small rockets to pull 50 feet ahead of the S-IVB, then turned the spacecraft around to simulate docking, as would be necessary to extract an LM for a moon landing. The next day, when the CSM and the S-IVB were about 80 miles apart, Schirra and his crewmates sought out the lifeless, tumbling 59-foot craft in a rendezvous simulation and approached within 70 feet.

Cunningham reported the spacecraft lunar module adapter panels had not fully deployed, which naturally reminded Thomas Stafford, the mission's capsule communicator, or capcom, of the "angry alligator" target vehicle he had encountered on his Gemini IX mission. This mishap would have been embarrassing on a mission that carried a lunar module, but the panels would be jettisoned explosively on future flights.
The Apollo vehicle and the CSM performed superbly. Durability was shown for 10.8 days -- longer than a journey to the moon and back.

Three of the five spacecraft windows fogged because of improperly cured sealant compound, a condition that could not be fixed until Apollo 9. Visibility from the spacecraft windows ranged from poor to good during the mission.

The CSM's service propulsion system, which had to fire the CSM into and out of the moon's orbit, worked perfectly during eight burns lasting from half a second to 67.6 seconds. Apollo's flotation bags had their first try out when the spacecraft, considered a "lousy boat," splashed down in the Atlantic southeast of Bermuda, less than 2 kilometers from the planned impact point. Landing location was 27 degrees, 32 minutes north, and 64 degrees, four minutes west. The module turned upside down, but when inflated, the brightly colored bags flipped it upright.

Apollo 7's achievement led to a rapid review of Apollo 8's options. The Apollo 7 astronauts went through six days of debriefing for the benefit of Apollo 8, and on Oct. 28, 1968, the Manned Space Flight Management Council chaired by George Mueller met at the Manned Spacecraft Center, investigating every phase of the forthcoming missionThe tired, but happy, voyagers were picked up by helicopter and deposited on the deck of the USS Essex by 8:20 a.m. EDT. Spacecraft was aboard the ship at 9:03 a.m. EDT.

Apollo 8

  • Leave the Earth’s atmosphere
  • Orbit the Earth
  • Travel to the Moon
    • Mid-course corrections
  • Orbit the Moon
    • Communications on the far side of the moon
    • Undock LM from CSM
  • Land on the Moon
    • LM descent
    • LM land
  • Re-enter an orbit of the Moon
    • LM ascent
    • Dock LM to CSM
  • Travel to the Earth
  • Orbit the Earth
  • Land on the Earth

 

The mission objectives for Apollo 8 included a coordinated performance of the crew, CSM, and the support facilities. The mission also was to demonstrate translunar injection; CSM navigation, communications and midcourse corrections; consumable assessment; and passive thermal control. The detailed test objectives were to refine the systems and procedures relating to future lunar operations.

The first midcourse correction occurred at about 10 hours, 55 minutes into the mission and provided a first check on the service propulsion system, or SPS, engine prior to committing spacecraft to lunar orbit insertion. The second and final midcourse correction prior to lunar orbit insertion occurred at 61 hours, 8 minutes, 54 seconds.

Loss of signal occurred at 68 hours, 58 minutes, 45 seconds when Apollo 8 passed behind the moon. At that moment, NASA's three astronauts became the first humans to see the moon's far side.

During the 20-hour period in lunar orbit, the crew conducted a full, sleepless schedule of tasks including landmark and landing site tracking, vertical stereo photography, stereo navigation photography and sextant navigation. At the end of the 10th lunar orbit, at 89 hours, 19 minutes, and 16 seconds, a three-minute, 23-second trans-Earth injection burn was conducted, adding 3,522 feet per second. Only one midcourse correction, a burn of five feet per second conducted at 104 hours, was required instead of the three scheduled.

Apollo 9

  • Leave the Earth’s atmosphere
  • Orbit the Earth
  • Travel to the Moon
    • Mid-course corrections
  • Orbit the Moon
    • Communications on the far side of the moon
    • Undock LM from CSM
  • Land on the Moon
    • LM descent (simulated)
    • LM land
  • Re-enter an orbit of the Moon
    • LM ascent (simulated)
    • Dock LM to CSM
  • Travel to the Earth
  • Orbit the Earth
  • Land on the Earth

The primary objective of Apollo 9 was an Earth-orbital engineering test of the first crewed lunar module, or LM. Concurrent prime objectives included an overall checkout of launch vehicle and spacecraft systems, the crew, and procedures. This was done by performing an integrated series of flight tasks with the command module, or CM, the service module, or SM, the joined command and service module, or CSM, the LM and S-IVB stage while they were linked in launch or various docked configurations, and while they were flying separate orbital patterns. The LM was to be tested as a self-sufficient spacecraft, and was also to perform active rendezvous and docking maneuvers paralleling those scheduled for the following Apollo 10 lunar-orbit mission.

The flight plan's top priority was the CSM and LM rendezvous and docking. This was performed twice - once while the LM was still attached to the S-IVB, and again when the LM was active. Further goals included internal crew transfer from the docked CSM to the LM; special tests of the LM's support systems; crew procedures; and tests of flight equipment and the extravehicular activity, or EVA, mobility unit. The crew also configured the LM to support a two-hour EVA, and simulated an LM crew rescue, which was the only planned EVA from the LM before an actual lunar landing.

The LM descent and ascent engines fired on orbital change patterns to simulate a lunar-orbit rendezvous and backup abort procedures. The CSM service propulsion system, or SPS, fired five times, including a simulation of an active rendezvous to rescue an LM that had become inactivate.

After separation of the CSM from the SLA in Earth orbit and jettison of the SLA's LM protective panels, the CSM was to transpose position and dock with the exposed LM. The docked modules were to separate and the spacecraft was to adjust its orbit 2,000 feet away from the S-IVB stage. The S-IVB engine was then to restart twice, placing the stage in an Earth-escape trajectory and into solar orbit. This would simulate a translunar injection of the stage for Apollo 10 and subsequent lunar missions. Other objectives included the multi-spectral photographic experiment for subsequent crewed spacecraft.

Apollo 10

  • Leave the Earth’s atmosphere
  • Orbit the Earth
  • Travel to the Moon
    • Mid-course corrections
  • Orbit the Moon
    • Communications on the far side of the moon
    • Undock LM from CSM
  • Land on the Moon
    • LM descent
    • LM land
  • Re-enter an orbit of the Moon
    • LM ascent
    • Dock LM to CSM
  • Travel to the Earth
  • Orbit the Earth
  • Land on the Earth

The Apollo 10 mission encompassed all aspects of an actual crewed lunar landing, except the landing. It was the first flight of a complete, crewed Apollo spacecraft to operate around the moon. Objectives included a scheduled eight-hour lunar orbit of the separated lunar module, or LM, and descent to about nine miles off the moon's surface before ascending for rendezvous and docking with the command and service module, or CSM, in about a 70-mile circular lunar orbit. Pertinent data to be gathered in this landing rehearsal dealt with the lunar potential, or gravitational effect, to refine the Earth-based crewed spaceflight network tracking techniques, and to check out LM programmed trajectories and radar, and lunar flight control systems. Twelve television transmissions to Earth were planned. All mission objectives were achieved.

Apollo 11

  • Leave the Earth’s atmosphere
  • Orbit the Earth
  • Travel to the Moon
    • Mid-course corrections
  • Orbit the Moon
    • Communications on the far side of the moon
    • Undock LM from CSM
  • Land on the Moon
    • LM descent
    • LM land
  • Re-enter an orbit of the Moon
    • LM ascent
    • Dock LM to CSM
  • Travel to the Earth
  • Orbit the Earth
  • Land on the Earth

The primary objective of Apollo 11 was to complete a national goal set by President John F. Kennedy on May 25, 1961: perform a crewed lunar landing and return to Earth.

The last problem to be solved was the actual landing on the moon.  In the series of Apollo missions, all other problems had incrementally been shown to be solved.