by Matthew Smith
figures by Bradley Wierbowski

Step aside, NASA. The 20^th century model of space exploration is running out of fuel, and private companies are now leading the race for human expansion across the galaxy. Elon Musk, Richard Branson, and Jeff Bezos are three of the billionaires leading this extraterrestrial adventure with their respective companies, SpaceX, Virgin Galactic, and Blue Origin. Bezos, the founder of Amazon and currently the wealthiest person in the world, has a vision of sending autonomous rovers to the Moon and helping to eventually create a Moon Village. He has explained that collaborations with the National Aeronautics and Space Administration (NASA) and other government agencies are encouraged and appreciated, but are no longer essential to achieve his goal. Musk, who co-founded Tesla, has already launched nine rockets within the first five months of 2018, one of which was the most powerful private spacecraft ever sent into orbit. Looking forward, SpaceX aims to complete its first manned mission to Mars in 2024, almost a decade earlier than NASA’s projections. Even the current US president is encouraging this shift to private companies driving innovation in space. With almost $1 billion invested in space-focused startups in the first quarter of 2018, the commercialized space industry shows no sign of slowing down.

Fundamentals of space: I want to break free

Gravity, the same phenomenon that keeps us all rooted to the ground, has been trying to keep private space companies from taking off. An extraordinarily large amount of force is necessary to break away from Earth’s gravitational pull, so launching objects into space isn’t easy and it’s certainly not cheap. For example, NASA’s Apollo program, which had the goal of putting astronauts on the moon, cost roughly $25 billion in the 1970s, which would be closer $140 billion in 2018 after correcting for inflation. This hefty price tag motivates companies to develop innovative tools for getting to space efficiently.

Escape velocity is defined as the minimum speed an object must reach to escape Earth’s gravitational pull; at sea level, this value is about 25,020 mph. In the past, NASA Space Shuttles have reached this velocity through a 3-part design: two solid rocket boosters (SRB), an external fuel tank, and an orbiter (Figure 1). The orbiter is where the primary cargo or passengers are held. It has 3 engines to power its travel. The SRBs are responsible for lifting the resting shuttle from the launch pad and propelling it faster than escape velocity. They break away from the external tank around an altitude of 25 miles so they can fall back to Earth to be collected and reused. The external tank, which provides the orbiter with fuel, separates from the orbiter at an altitude of around 70 miles. The external tank, however, is not reusable because it disintegrates upon reentry due to its size and the altitude of its separation, which is an expensive loss.

 

Figure 1. Space crafts Various crafts have been used to accomplish specific missions in space. The first panel on the left depicts SpaceX’s Falcon Heavy, currently the world’s most powerful rocket. There are three main stages: the boosters (or first stage), the second stage, and the payload. The flames beneath a component indicates that it is actively propelled. The second panel depicts NASA’s Saturn V rocket with the Apollo spacecraft. This design was used from 1967-1973 to send the first astronauts to the moon. The craft has four main parts: the first stage, second stage, third stage, and the Apollo spacecraft (which is where the astronauts resided). The third panel depicts the NASA Space Shuttle, which was used from 1981-2011 to send astronauts to Earth’s LEO and to reside and conduct experiments on the International Space Station. The Space Shuttle has three main parts: boosters, external fuel tank, and orbiter. The orbiter’s aerodynamic design allowed it to glide back into Earth’s atmosphere, and it was one of the first reusable space crafts. The last panel shows Virgin Galactic’s craft design, which has two parts: the WhiteKnightTwo and the SpaceShipTwo. The WhiteKnightTwo design allows more freedom in location of launch because it takes off very similarly to a commercial plane, which is useful for its primary purpose of space tourism.

Efficiently launching rockets

Private companies have been racing forward with new spacecraft and rocket designs to make space travel more efficient and economical. Elon Musk and SpaceX may be leading the pack with the recent successful launch of the Falcon Heavy rocket, the most powerful operational rocket in the world. The Falcon Heavy combines the efficiency and power of previous NASA technology to produce a spacecraft that can navigate the solar system for less than 1/10^th the cost of the NASA rocket that propelled astronauts to the moon. The Falcon Heavy has 3 main parts: boosters, stage-2, and the payload (Figure 1). Its three boosters, which are responsible for propelling the ship into orbit, are significantly more powerful than the NASA Space Shuttle’s boosters. All three boosters could be reused, but the center booster needs to stay attached to the rocket for a longer time to provide more power when transporting heavier cargo, which makes recapture more challenging. Each booster contains nine Merlin engines, which were designed by SpaceX to inject fuel more efficiently than any other rocket engine. Stage-2, also known as the second or upper stage, is used after the boosters cut out. It can be restarted multiple times and is used to deliver cargo to various levels of Earth’s orbit, as well as fueling return trips from distant planets. Finally, the payload is similar to the orbiter on a Space Shuttle, but the Falcon Heavy has various modules that can be adapted to the size and type of cargo. SpaceX is redefining the space equation through its efficient Merlin engine design and reusable components.

To Low Earth Orbital and Beyond

Most of NASA’s manned missions have been conducted in Low Earth Orbit (LEO), which is anything with an altitude above 100 miles and below 1240 miles (Figure 2) and circling the Earth with an interval of 85-127 minutes. An orbit is defined as a regularly repeating path that an object takes around another object, and objects that are orbiting Earth (both natural and man-made) are called satellites. If an object doesn’t reach an altitude of around 100 miles, then it will not enter Earth’s orbit and will plummet quickly down to Earth. Companies have been populating LEO since the early 1960s by launching manufactured satellites for television, surveillance, communication, and other purposes. All commercial space operations currently occur within LEO, but this is projected to change in the next few years. For example, a company named Moon Express has a name that fits its mission to become the first private company to land on the moon. Moon Express has engineered autonomous robot explorers specialized to function on the moon, and its inaugural mission is projected for 2019. Jeff Bezos also recently announced Blue Origin’s plans to build a 4-legged Moon Lander to further explore the moon. He is collaborating with NASA to arrive by 2020. In 2017, Elon Musk projected that SpaceX would send two citizens to the moon and back in 2018, but recent statements have suggested that this flight will most likely occur around 2020. Elon Musk and SpaceX are also leading the race to Mars, with the first Mars mission projected to take place in 2022. SpaceX has already started to build the rocket and spacecraft that will make the journey, the BFR. The abbreviation has no official name, but it is professionally referred to as the “Big Falcon Rocket” (and casually referred to as the Big *explicative*-ing Rocket).

Figure 2. Earth’s orbitals Different objects exist at different altitudes above Earth. These altitudes are separated into three main groups: Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and High Earth Orbit (HEO). Low Earth Orbit is around an altitude of 100-1200 miles above Earth’s surface. The international space station resides inside LEO at around 211 miles above sea level. The Medium Earth Orbit is defined by an altitude from 1201-22,236 miles above sea level. Most GPS satellites exist in this region. Lastly is High Earth Orbit, which is anything with an altitude greater than 22,237 miles above sea level. The moon resides at an altitude of 238,607 miles above sea level, which is in HEO.

How can I get to space?

Companies like Virgin Galactic hope to make trips to space available for purchase by non-astronauts. Led by billionaire Richard Branson, Virgin Galactic has already sold over 600 seats on its commercial spacecraft for $250,000 each. As of now, Virgin Galactic is only planning flights just below an altitude of 100 miles (sub-orbital) and are using a unique two-ship system, which requires less power (and therefore less money) than competitors’ systems (Figure 1). The WhiteKnightTwo carries a smaller passenger shuttle, called the SpaceShipTwo, up to 50,000 feet, where the SpaceShipTwo is launched and ignites its rocket. Having the passenger shuttle launch from the air provides more freedom and flexibility because it eliminates the need for a launch pad.

There are, however, some incredible opportunities to get yourself and/or ideas to space for free. Although NASA just ended its latest search for astronauts, they will surely be looking for new recruits within the coming years. The odds of being selected, however, are low: only 17 individuals were selected from almost 20,000 applicants, ranging in ages from 29-41. If you’re not quite old enough to be launched into space, then you can try launching your science experiment with Genes in Space (GiS). This program, which is a collaboration between miniPCR, Boeing, and NASA, is a national competition for middle and high schoolers to pitch projects for astronauts to conduct in space. The winning proposals for 2017 included experiments to design a cheap and efficient test to evaluate cancer risk for astronauts and measure immune health.

The barriers to space are weakening as society advances and private companies continue to push innovation, and this trend shows no signs of slowing down. What was once extraterrestrial science fiction has already become reality. In the next few years, we’ll begin to see construction of a space station by the Moon, the first manned missions to Mars, and the beginning of a new era of space colonization. All of these missions will require heavy involvement from private companies. We’re entering a defining moment in space exploration and it’s exciting to see what discoveries will be realized through our collaborative advancements into space.

Matthew Smith is a fourth-year graduate student in the Molecules, Cells, and Organisms program at Harvard University.

For more information:

• To learn more about commercial space exploration, check out this CNN Tech article
• For more information about the role of NASA in commercial space exploration, visit their website

This article is part of the 2018 Special Edition — Tomorrow’s Technology: Silicon Valley and Beyond