Elon Musk probably took it for granted that his space exploration company would launch and land the first private space mission to Mars. However, if he thought that SpaceX had cornered the market, he no longer does. This week, two space startups announced a bold plan to send a lander to Mars by the end of 2024. The technical hurdles are high. But even if the mission fails, it will create something important and lasting: a space race between private companies, not nation states. Companies have always had a role in space exploration. The early achievements of the National Aeronautics and Space Administration, including the Apollo moon landings, depended on private space contractors. Later, companies came to dominate the design and operation of communications and other types of commercial satellites. But exploration for exploration’s sake has remained an activity pursued by rich countries for prestige, honor and military advantage rather than profit. The problem is that exploration and science are sometimes too difficult and expensive to justify the pursuit of glory. For most of the space age, Mars has been that kind of destination, with about half of all missions hoping to land on or orbit it and its moons. In the early 2000s, Musk famously branched out from pioneering electric cars and began investigating NASA’s plans to send people to Mars. When he found that there were none, he began laying the groundwork for SpaceX. Musk’s — and SpaceX’s — stated long-term goal is to make “humanity multiplanetary.” To get there, SpaceX and its engineers have tried to lower the cost of getting into space by developing reusable rocket systems. They have succeeded better than anyone could have imagined. In 2011, a kilogram of cargo launched on the NASA space shuttle cost about $30,000; today, a kilogram of payload launched on SpaceX’s workhorse Falcon 9 rocket costs about $1,200. Lower costs have not only expanded the market for launch services beyond governments and the biggest corporations, they’ve also allowed Musk to add a note of practicality to his big dreams of Mars. In April 2016, SpaceX announced plans to send an unmanned spacecraft to the Martian surface as soon as 2018. The plan sounded plausible; both the rocket and the lander were in advanced stages of development (and both have since been launched). The mission would be funded by SpaceX and Musk, with operational and technical support from NASA, but no money. The plan proved to be politically and financially unsustainable, and Musk canceled it just over a year after the initial announcement. Instead, he announced a new Mars mission architecture, highlighted by the development of a reusable spacecraft called Starship, which SpaceX describes as the “most powerful launch vehicle ever developed.” Starship is expected to make its first orbital test flight soon, but there is no announced timeline for travel beyond Earth. This does not mean that there is no hope for a commercial mission to Mars. In the two decades since SpaceX was founded, the global space sector has grown into a $447 billion industry (it was worth $162 billion in 2005), with at least 20 companies capable of launching satellites and orbitals. As the number of companies grows, so does entrepreneurship and expertise. And some of that expertise pays off on its own. Tom Mueller is one of those entrepreneurs. In 2002, he was SpaceX’s No. 1 employee, and over an 18-year career, he played a critical role in the development of engines and propulsion systems for the company’s rockets and spacecraft. After he retired, he indulged his passion for racing cars until he founded Impulse Space last year. The company is focused on building sustainable propulsion systems to move objects already in space from satellites to space junk. That’s the kind of brash ambition that made SpaceX a success, so it shouldn’t come as a total surprise that Mueller is looking to beat his former boss to Mars. Impulse Space’s partner in the venture is Relativity Space Inc., a 7-year-old company that plans to use 3D printing to make reusable launch vehicles. Like Impulse, Relativity has SpaceX DNA; its vice president of engineering and manufacturing, Zach Dunn, worked under Mueller for years. Last year, he approached Mueller about putting together a mission that would draw attention to its new rocket, which is intended to compete directly with SpaceX. Will it work? The architecture of the Mars mission leverages the innovative capabilities of both companies, while also relying on NASA for safe access to the Martian atmosphere. (NASA landed a rover there last year.) If the effort is successful, NASA and other companies are likely to embrace the possibility of paying for transportation on future missions. It’s a space race worth cheering for. Government-run space programs continue to advance science and engineering around the world. But the future of space exploration will be defined by fast-paced private companies competing with each other. The race to put the first commercial rocket on Mars does not have the same appeal as sending the first man to the moon. But the achievement would be equally important for the evolution of a multiplanetary species. Let the best rocket win. Bloomberg