Book review by Dennis D. McDonald

COMING HOME is another well-illustrated NASA e-book containing much detail about an important topic of aerospace history. This time the subject is the safe return of space vehicles to earth.

The theory behind what happens when reentering the Earth’s atmosphere is extensive and dates from the early 20th century. The challenge: heat and pressure. Hitting the atmosphere at high-speed generates high heat. Hitting the atmosphere at over 10,000 miles per hour generates VERY high heat. What do you do with all the heat while slowing the vehicle to a speed where a controlled trajectory and landing are possible? And, how do you maintain a livable temperature inside the vehicle when human occupants are present?

The book details first the theoretical pioneers, then the beginning experiments with models and wind tunnels, and finally “hands-on” experience with ballistic missile reentry nose cones protected from burn-up by shape, ablative materials, and heat resistant alloys. At the same time a variety of powered and unpowered “spaceplane” shapes were being tested, the idea being that it was preferable to land a winged vehicle returning from space on a runway rather than splash into the ocean hanging from parachutes.

The book provides a lot of technical detail about chemicals, structural engineering, competing designs, failed experiments while addressing different variables such as speed, temperature, and angle of attack when slicing through the atmosphere.

Those who have grown up with memories of only the high points of space travel—launch, landing, reentry, and splashdown—may find all of this a bit hard to take. But it’s good to know that there is a lot of complex work on solving the unknowns raised by the needs of returning humans safely some from space. Knowing the details makes one even more appreciative of the challenges and how they are being overcome.

You also learn from reading this why some of the next generation of space “capsules” will be shaped somewhat like those in the past and retrieved via parachute. While they may look similar the materials and shape details are different.

At the same time, some privately developed launch vehicles currently under development with vertical landing capabilities display very different approaches to launch vehicle construction than was possible in the past. Are these differences because the materials and control systems now available are superior to those from the past? Or, are they different because they have been developed independently without as much benefit of prior experience since they have been developed in a competitive and more secretive environment? Sometimes competing teams working independently solve the same problem in the same way. Sometimes they develop very different solutions to the same problem.

Ultimately in expensive high-stakes games such as space travel someone—usually a government—makes a choice between solutions offered by different teams. It happened this way in the Russian space program, and, as illustrated in COMING HOME, it happened in the U.S. as well.

Related reading:

• Mary Roach’s PACKING FOR MARS
• Craig Nelson’s ROCKET MEN: The Epic Story of the First Men on the Moon
• Boris Chertok’s ROCKETS AND PEOPLE VOLUME 3: HOT DAYS OF THE COLD WAR
• Walter A. McDougall’s THE HEAVENS AND THE EARTH: A POLITICAL HISTORY OF THE SPACE AGE
• Gerard J. DeGroot’s DARK SIDE OF THE MOON
• China as Manufacturer to the World … and Beyond
• Why I Care about India’s Chandrayaan-1 Lunar Mission
• Andy Weir’s THEMARTIAN
• Ridley Scott’s THE MARTIAN

Review copyright © 2015 by Dennis D. McDonald