The Future of Space Exploration
author Paul Boșcu, August 2017
While the current lunar exploration initiative has been justified as a “stepping stone” toward Mars, human missions to Mars represent a major step up in complexity, scale, and rigour compared to lunar missions.
More than 40 years after the last human being walked on the Moon, NASA plans to return to that world. A replacement for the space shuttle fleet is the first item on NASA’s agenda. Rather than using the same spacecraft to both carry heavy payloads and passengers to orbit, the job will be split between two different types of spacecraft. NASA will use an unmanned heavy-lift launch vehicle exclusively for heavy payloads and a smaller shuttle for ferrying passengers to and from space. The lunar exploration program will require entirely new spacecraft. To this end NASA is developing the Orion crew vehicle.

The first of the new launch vehicles to replace the space shuttle will be the Space Launch System. It will transport the Orion crew exploration vehicle and its crew and cargo to a low orbit of Earth. The Orion, in turn, will be the modern equivalent of the Apollo command module.

The Orion spacecraft will be able to carry more people and more cargo, equipment, and supplies than the Apollo spacecraft of the 1960s and 1970s. It will be able to carry everything the first mission requires, as well as extra materials and supplies for subsequent missions. This way, each mission will build on the ones before it.

The Orion crew vehicle will also be capable of carrying crew and cargo to and from the International Space Station. It will even be part of the system of spacecraft used in Mars exploration missions.

Although Orion’s overall design resembles the Apollo spacecraft, it takes advantage of twenty-first century advances in computers, electronics, life support, propulsion, and heat-protection systems.

We’ve already been there, many people say, so why go back? It will cost billions of dollars. There are a number of answers to those questions. Some of the reasons are purely scientific, but others are very practical. Being able to explore and study the surface of the Moon for prolonged periods will allow scientists to discover what resources are there.

Scientists want to find out if the Moon has materials for construction and industry. These resources would be important for creating permanent, large-scale colonies on the Moon. A permanent presence on the Moon will let scientists explore farther and in more detail than they ever could during brief visits such as the Apollo program.

Scientists and engineers will be able to test technologies, systems, flight operations, and exploration techniques. Their findings will help with future missions to Mars and other places in the solar system.

Pure scientific research on the Moon may result in discoveries that will benefit life on Earth, such as new medical techniques and medicines.

Large scale exploration of the Moon will require international cooperation and could expand Earth’s economy by creating the new industries and jobs needed to support such a large undertaking in space.

The United States is not the only nation interested in going to the Moon. Its rival this time, however, is China. China sent its first astronaut into orbit in 2003, becoming only the third country to put a human being into space. (Of course, many non-U.S. and non-Russian astronauts and cosmonauts have flown on U.S. and Russian spacecraft.)

Chinese space officials set their sights on the Moon as one goal in an ambitious multistep space program. After robotic probes and initial human exploration, China plans to create permanent bases on the Moon.

NASA’s plans to reach Mars involve the use of the Space Launch System and Orion vehicles. But some scientists and engineers do not think that NASA has the most practical plan for exploring Mars. One such scientist is Robert Zubrin, whose Mars Direct plan appears to be the fastest, most economical project for reaching and exploring the Red Planet.

Zubrin’s Mars Direct would require the launch of an unmanned Earth Return Vehicle (ERV) directly from Earth’s surface to Mars. It would be launched by a heavy-lift booster about the same size as the Apollo Saturn V. It would land on Mars eight months later. The ERV would carry a cargo of hydrogen fuel, a small automatic chemical factory, and a compact nuclear reactor. The chemical factory would begin combining hydrogen with carbon dioxide from Mars’s atmosphere. This would create methane and oxygen. After ten months, 110 tons (100 metric tons) of methane and oxygen rocket propellants would accumulate.

Twenty-six months after launching the ERV, a second spacecraft, the Mars Habitat Unit (MHU), would be boosted into space. The MHU would carry a crew of four to six astronauts. It would arrive at Mars six months later. Using the MHU as its base and living quarters, the crew would spend eighteen months exploring the Martian surface, using a small rover powered by excess methane and oxygen that the factory produced. At the end of the mission, the astronauts would use the fully fueled ERV to return to Earth, leaving their abandoned habitat for future explorers.

While the current lunar exploration initiative has been justified as a “stepping stone” toward Mars, human missions to Mars represent a major step up in complexity, scale, and rigour compared to lunar missions. Lacking a capability for rapid abort (such as exist for lunar missions), all systems for Mars missions MUST function for up to 2.7 years and there is no escape if a subsystem fails. Radiation in space poses a threat to humans embarked on missions to the Moon or Mars.

There is considerable uncertainty as to the biological effects of various levels of radiation exposure, and how much exposure should be permitted in deep space.

To test equipment and techniques for the eventual exploration of Mars, a private organization called the Mars Institute has created a Mars base on Earth. It is located on Devon Island, far north of the Arctic Circle. The cold, barren, nearly lifeless island is about as close to Mars as anyone could find on this planet. Although no place on Earth is exactly like Mars, the Devon Island base allows the scientists there to develop special equipment and exploration techniques for future Martian explorers.

Scientists have been able to test ground-penetrating radar surveys, which allow scientists to “see” beneath the surface of the ground.

Field spectrometry helps scientists determine what elements make up rock and soil. These three-dimensional stereo cameras offer realistic three dimensional images. They have also done some test drilling into permafrost (a layer of permanently frozen water beneath the surface soil. On Mars the permafrost may be hundreds of feet thick). Tests of robotic helicopters, rovers, and space suits have also been done.

The idea of traveling into space for fun—in orbiting space hotels, for example—has been around for a long time. Companies such as Space Adventures have been advertising space tourism. Some have even proposed designs for their own spacecraft. But so far none of them has actually flown any passengers. Presently, all space tourists made it into space with NASA and Roscosmos launch vehicles.

The first tourists in space flew in the 1980s—and even these are borderline cases, depending on just how you define the word tourist. When U.S. senator Jake Garn flew on the space shuttle in 1985 and U.S. representative Bill Nelson in 1986, they had no real work to do as astronauts. They were, in effect, just along for the ride. However, as members of committees overseeing NASA funding, they weren’t exactly tourists either.

MirCorp—a private company operating the Mir space station in its final years—saw space tourism as a way to help defray some of the costs of maintaining the station. They began advertising for people willing to pay several million dollars to spend a few days in the cramped quarters of the station. A U.S. millionaire, Dennis Tito, was the first to apply, but the decision to end the Mir space station came before he had his chance to visit it. Instead, he traveled to the ISS in 2001, where he stayed for a week. Tito was the first real space tourist in that he paid his own way and had no other agenda but his own pleasure.

Tito was followed in 2002 by South African Mark Shuttleworth. American Gregory Olsen went in 2005. Iranian American Anousheh Ansari went in 2006. In 2007 Charles Simonyi, one of the original employees of Microsoft, got his chance. All of these space tourists were wealthy people able to afford the multimillion dollar ticket into space.

Another U.S. senator who flew in the shuttle might be a little more deserving of the label space tourist. Mercury astronaut John Glenn returned to space in 1998 aboard the space shuttle, becoming, at the age of seventy-seven, the oldest human to fly in space.

Another U.S. senator who flew in the shuttle might be a little more deserving of the label space tourist. Mercury astronaut John Glenn returned to space in 1998 aboard the space shuttle, becoming, at the age of seventy-seven, the oldest human to fly in space.

Numerous companies have been trying to establish regular space tourist flights. Most of these involve suborbital flights similar to the one Alan Shepard made in 1961, when he rode Mercury 3 into space. Instead of going into orbit, a suborbital flight would simply take passengers up to about 60 to 100 miles (97 to 160 km). They could experience a few minutes of weightlessness and see the black sky of space and the curvature of Earth. Even in the foreseeable future, however, this type of travel will still not be readily accessible to the average person.

More ambitious companies plan to offer trips lasting a few days to several weeks in Earth’s orbit and even trips around the Moon, with a stopover at the International Space Station. Others plan to bypass the ISS by building their own space stations. Several Japanese companies have plans for private space stations—or space hotels— as does Hilton International and Richard Branson’s Virgin Galactic.

A big step toward the achievement of space tourism was the Ansari X Prize. The X Prize was originally established to encourage public enthusiasm for space exploration. The goal of the X Prize was eventually changed slightly. It was aimed at encouraging the development of low-cost spaceflight in the private sector, as well as the development of new imaginative technologies and techniques. To win the $10 million prize, the successful entrant would have to launch a reusable, piloted spacecraft into space twice within a two-week period.

The prize was named for Amir Ansari and his sister-in-law Anousheh, who contributed the prize money. It was modeled after the great aviation prizes of the 1920s and 1930s, such as the $25,000 Orteig Prize that inspired Charles Lindbergh to fly across the Atlantic Ocean.

Twenty-six companies and individuals entered the contest. Some entrants developed spacecraft with fairly conventional designs. For instance, the Canadian Arrow resembled the German V-2 rocket of World War II. Other designs were very imaginative.

SpaceShipOne, which had been created by Scaled Composites, a company operated by Bert Rutan, won the prize. Its two competitive flights were made on September 29, 2004, and October 4, 2004. Multibillionaire space enthusiast Paul Allen, one of the founders of Microsoft, provided funding for the project. The spacecraft is on exhibit at the Smithsonian National Air and Space Museum in Washington, D.C.

Plans for human presence in space include permanent colonies on the Moon and Mars. Many people have proposed ideas for space colonies. Space colonies would be enormous structures housing thousands of people who would live there permanently. People could live and even raise families in space colonies.

Scientists have created many different designs for space colonies, but most are vast cylinders or rings more than 1 mile (1.6 km) wide. They slowly rotate to provide gravity for the inhabitants. Inside would be farmland, parks with lakes and streams, houses, schools, and factories.

Other plans for humans in space include transforming planets such as Mars or Venus into worlds more like Earth. Humans could live on the surface unprotected by space suits or special habitats. This is called terraforming.

Mars might be terraformed by increasing its air pressure to a point where liquid water could exist on the surface. This might be accomplished by vaporizing the vast quantities of carbon dioxide ice found on and beneath the surface. Carbon dioxide is a heavy gas, and because of its weight, air pressure would increase rapidly. The gas would create a greenhouse effect by trapping solar heat on the surface, and the planet would grow warmer.

With liquid water and warmer temperatures, plants would thrive and start producing oxygen. It may take hundreds or perhaps even thousands of years, but Mars would eventually become an Earthlike world on which people could live openly without needing space suits.

NASA has plans for the human exploration of asteroids, perhaps to eventually mine them for their vast reserves of valuable minerals and nearly pure metals. Human explorers may also visit some of the planet-sized moons of Jupiter and Saturn.

On Jupiter’s moon Europa, scientists will look for life in the great seas that exist beneath the ice. Saturn’s moon Titan has an atmosphere containing methane, a rocket fuel. This moon could become a way station between Earth and the outer limits of the solar system.

Why send humans to an asteroid in the first place? You don’t have to have people there to do good near-Earth asteroid science, observes Dan Durda, a space scientist from the Southwest Research Institute in Boulder, Colorado. “But look at how having astronauts actually there on the Moon improved the both the quantity and quality of the science return from Apollo. People have the judgment and creativity to select the best places to explore coupled with the dexterity to gather the best samples that no machine will have for quite a while.”

Voyages beyond the solar system are for the distant future. This is mainly because of the incredible scale of the distances involved. Apollo 11 took three days to travel the 250,000 miles (402,000 km) that separate Earth from the Moon. The distance to the nearest star—Alpha Centauri—is 6,750,000,000,000 times greater. To get to even the nearest star, spaceships would have to travel many times faster than Apollo 11. But greater speeds require greater amounts of energy and fuel—or, more likely, entirely new types of propulsion.

Ion engines, for example, have very low thrusts but can run continuously for months or years, eventually building speeds up to a significant fraction of the speed of light. The trip might then be reduced from thousands of years to decades.

Many authors have proposed the generation starship, which would contain thousands, maybe even millions, of people. Entire families would be aboard, along with plants, animals, and everything else necessary for the existence of an entire culture. None of the people would ever see Earth again—nor would they ever see the starship’s destination. Only their descendants would see it.