A few months before the MarCO satellites launched with the InSight lander on the large Atlas V rocket, the much smaller Electron rocket took flight for the first time. Developed and launched from New Zealand by Rocket Lab, Electron is the first of a new generation of commercial, small satellite rockets to reach orbit.
The small booster has a payload capacity of about 200kg to low-Earth orbit. But since Electron's debut, Rocket Lab has developed a Photon kick stage to provide additional performance.
In an interview, Rocket Lab's founder, Peter Beck, said the company believes it can deliver 25kg to Mars or Venus and up to 37kg to the Moon. Because the Photon stage provides many of the functions of a deep space vehicle, most of the mass can be used for sensors and scientific instruments.
"We're saying that for just $15 to $20 million you can go to the Moon," he said. "I think this is a huge, disruptive program for the scientific community."
Of the destinations Electron can reach, Beck is most interested in Venus. "I think it's the unsung hero of our Solar System," he said. "We can learn a tremendous amount about our own Earth from Venus. Mars gets all the press, but Venus is where it’s really happening. That’s a mission that we really, really want to do."
There are other, somewhat larger rockets coming along, too. Firefly's Alpha booster can put nearly 1 ton into low-Earth orbit, and Relativity Space is developing a Terran 1 rocket that can launch a little more than a ton. These vehicles probably could put CubeSats beyond the asteroid belt, toward Jupiter or beyond.
Finally, the low-cost launch revolution spurred by SpaceX with larger rockets may also help. The company's Falcon 9 rocket costs less than $60 million in reusable mode and could get larger spacecraft into deep space cheaply. Historically, NASA has paid triple this price, or more, for scientific launches.
There will be some trade-offs, of course. One of the reasons NASA missions cost so much is that the agency takes extensive precautions to ensure that its vehicles will not fail in the unforgiving environment of space. And ultimately, most of NASA's missions—so complex and large and capable—do succeed wonderfully.
CubeSats will be riskier, with fewer redundancies. But that's okay, says Pomerantz. As an example, he cited NASA's Curiosity rover mission, launched in 2011 at a cost of $2.5 billion. Imagine sending 100 tiny robots into the Solar System for the price of one Curiosity, Pomerantz said. If just one quarter of the missions work, that's 25 mini Curiosities.
Frank agreed that NASA would have to learn to accept failure, taking chances on riskier technologies. Failure must be an option.
"You want to fail for the right reasons, because you took technical chances and not because you messed up," she said. "But I think you could create a new culture around failure, where you learn things and fix them and apply what you learn to new missions."
NASA seems open to this idea. Already, as it seeks to control costs and work with commercial partners for its new lunar science program, the space agency has said it will accept failure. The leader of NASA's scientific programs, Thomas Zurbuchen, said he would tolerate some misses as NASA takes "shots on goal" in attempting to land scientific experiments on the Moon. "We do not expect every launch and landing to be successful," he said last year.
At the Jet Propulsion Laboratory, too, planetary scientists and engineers are open-minded. John Baker, who leads "game-changing" technology development and missions at the lab, said no one wants to spend 20 years or longer going from mission concept to flying somewhere in the Solar System. "Now, people want to design and print their structure, add instruments and avionics, fuel it and launch it," he said. "That's the vision."
Spaceflight remains highly challenging, of course. Many technologies can be miniaturized, but propulsion and fuel remain difficult problems. However, a willingness to fail opens up a wealth of new possibilities. One of Baker's favorite designs is a "Cupid's Arrow" mission to Venus where a MarCO-like spacecraft is shot through Venus's atmosphere. An on-board mass spectrometer would analyze a sample of the atmosphere. It's the kind of mission that could launch as a secondary payload on a Moon mission and use a gravity assist to reach Venus.
"There’s so much of the Solar System that we have not explored," Baker said. "There are how many thousands of asteroids? And they’re completely different. Each one of them tells us a different story."
One of the exciting aspects of bringing down the cost of interplanetary missions is that it increases access for new players—smaller countries like Poland as well as universities around the world.
"I think the best thing that can be done is to figure out how to lower the price and then make this technology publicly available to everyone," Baker said. "As more and more countries get engaged in Solar System exploration, we’re just going to learn so much more."
Already, organizations such as the Milo Institute at Arizona State University have started to foster collaborations between universities, emerging space agencies, private philanthropy, and small space companies.
Historically, there have been so few opportunities for planetary scientists to get involved in missions that it has been difficult for researchers to gain the necessary project management skills to lead large projects. With a larger number of smaller missions, Frank said she believes it will increase the diversity of the planetary science community.
In turn, she said, this will ultimately help NASA and other large space agencies by increasing and developing the global pool of talent for carrying out the biggest and most challenging planetary science missions that still require billions of dollars and big rockets. Because, while some things can be done on the cheap, really ambitious planetary science missions like plumbing the depths of Europa's oceans or orbiting Pluto will remain quite costly.