Alan Hale, For the Daily News Published 8:28 p.m. MT April 5, 2017 | Updated 8:29 p.m. MT April 5, 2017

Alan Hale(Photo: Courtesy Photo/Alan Hale)

A lot of words and phrases can be used to describe space travel. Complex and difficult come to mind, and especially if were talking about transporting humans in space as well as to and from space, hazardous and dangerous certainly are appropriate, as we consider all the various hazards of spaceflight, the multitudes of things that can go wrong, and the difficulties involved in addressing any of these.

Expensive is another word that is very appropriate when describing space travel. To get to space at all we have to launch away from Earths surface and fight against Earths gravity; this can be thought of as analogous to climbing up out of a deep well, and, indeed, space engineers often refer to the Earths gravity well. Climbing out of the Earths gravity well requires energy lots of it and this in return requires fuel, and lots of it. As anyone who has driven a car knows, fuel can be expensive.

Once we have climbed out of Earths gravity well, we can then achieve low-Earth orbit. From there, travel to other destinations including the moon, other planets, etc. becomes considerably less difficult, at least when we discuss energy and fuel. As the late science fiction writer Robert Heinlein is said to have remarked around 1950, Get to low-Earth orbit and youre halfway to anywhere in the solar system.

From a practical perspective, especially when were dealing with human space travel, there is much more involved than this, but from a strict perspective of energy involved, there is a fair amount of truth in Heinleins statement.

Another major factor which makes spaceflight so expensive is that especially during spaceflights early days for the most part, every piece of space hardware is built and used only once, and then discarded. This includes the launch rocket and its various stages, and for a human mission the capsule, or whatever is carrying the human cargo. The magnitude of the expense involved can be realized if we imagine that, before every airplane flight, a complete new airplane had to be built, that would then be discarded after it had completed a single flight. Air travel would be extremely expensive in such a climate, and the aviation industry that we have today could not even begin to exist.

The concept of reusability has thus been a desired element of spaceflight for some time. Indeed, such a goal was a major element of the Space Shuttle system, with its reusable orbiters and solid-fuel booster rockets being among the major components. As things turned out, in order to be sold to the American public and, more importantly, to Congress that funded the program the Space Shuttle ended up having to be all things for all people, which enormously increased its complexity and thus the associated expenses.

The Space Shuttle therefore never achieved the dramatic reductions in spaceflight costs that had been envisioned for it, but it nevertheless demonstrated that reusability is a viable concept when it comes to space endeavors.

There have been other efforts to develop lower-cost reusable spaceflight systems over the years. One of the higher-visibility efforts was the Delta Clipper Experimental (DC-X) program carried out by McDonnell Douglas Aerospace, which involved a single-stage rocket that could be launched, landed, refurbished and launched again. The DC-X performed several test flights at White Sands Missile Range, New Mexico during the mid-1990s, and while it was never designed to reach orbit, it successfully demonstrated that a well-designed launch vehicle could be used and reused over and over again.

The overall scheme at the time was for the DC-X effort to segue into programs like the X-33 that would in turn lead to fully reusable, and commercially driven, launch systems that could travel to and from low-Earth orbit. Unfortunately, due to both technological and political obstacles, programs like X-33 never came to fruition.

Enter Space Exploration Technologies, or SpaceX, the brainchild of entrepreneur Elon Musk. Musk founded SpaceX, currently based in Hawthorne, California, in 2002 with the goal of developing privately-funded reusable launch vehicles that can travel to and from low-Earth orbit.

While, as would be true for any such endeavor that is pushing the envelope like this, there have been some setbacks along the way, SpaceX has scored some remarkable achievements as well, including being the first private company to launch a spacecraft to orbit and successfully recover it back on Earth. Under contract to NASA, in May 2012 SpaceX became the first private company to launch a successful cargo resupply mission to the International Space Station (ISS),which it has been doing on a semi-regular basis ever since.

SpaceX has just achieved what could be considered its most remarkable success yet. In April 2016 SpaceX launched one of its cargo resupply missions to the ISS, and meanwhile successfully landed the Falcon 9 launch rockets first stage on a floating ocean barge. Then, just a week ago, SpaceX used this same recovered first stage as part of a Falcon 9 rocket to launch a communications satellite to geostationary orbit, and again successfully landed the first stage on the floating barge. This marks the first time that a rocket has been successfully reused to launch payloads into Earth orbit.

There is much more in SpaceXs future. Under another NASA contract SpaceX has been developing a human-rated capsule that can carry astronauts to and from the ISS, and hopes to make an unmanned test run later this year, and the first crewed launch to the ISS in 2018. SpaceX has also recently announced plans to send two people on a flight around the moon conceivably as early as next year and ultimately is working on a launch system that can send people to Mars. Meanwhile various other commercial space companies are developing plans and systems of their own. Perhaps, through such efforts, another word that may someday describe human spaceflight is common.

Alan Hale is a professional astronomer who resides in Cloudcroft. Hale is involved in various space-related research and educational activities throughout New Mexico and elsewhere. His web site is http://www.earthriseinstitute.org

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