Science
NASA patented a faster, cheaper route to the moon. The first spacecraft to use it could make Nobel Prize-winning discoveries about the universe.
dmosher@businessinsider.com (Dave Mosher)
Business InsiderSeptember 2, 2020, 7:28 AM CDT
An illustration of the showing the Dark Ages Polarimeter Pathfinder or DAPPER spacecraft orbiting past the far side of the moon. <p class="copyright"><a href="https://www.colorado.edu/ness/dark-ages-polarimeter-pathfinder-dapper" rel="nofollow noopener" target="_blank" data-ylk="slk:University of Colorado Boulder; NASA" class="link rapid-noclick-resp">University of Colorado Boulder; NASA</a></p>
An illustration of the showing the Dark Ages Polarimeter Pathfinder or DAPPER spacecraft orbiting past the far side of the moon.
University of Colorado Boulder; NASA
NASA patented an efficient new trajectory for sending smaller robotic spacecraft to the moon.
The agency says it patents and licenses technologies to ensure they can achieve the "widest distribution" possible.
The new trajectory may help a planned spacecraft, called the Dark Ages Polarimeter Pathfinder, reach lunar orbit and repeatedly fly through a "cone of silence" on the far side of the moon.
That spacecraft could detect signals from the first stars, galaxies, black holes, and more, leading to big discoveries about how the universe evolved to its current form.
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The moon is both seductively close to Earth and cosmically far away: Decades after the end of the Space Race, it remains extraordinarily expensive and difficult to actually get there.
The journey just got a bit easier, however, thanks to a freshly published NASA invention. The agency's patent doesn't cover a new piece of equipment or lines of code, but a trajectory a route designed to save a lunar-bound mission time, fuel, and money and boost its scientific value.
The US Patent and Trademark office granted and published NASA's patent for a series of orbital maneuvers on June 30, which Business Insider first learned about via a tweet by lawyer Jeff Steck.
The technique isn't meant for large spaceships that carry astronauts or rovers, but for smaller, more tightly budgeted missions tasked with doing meaningful science. And the first spacecraft to take advantage of this new orbital path could deliver unprecedented discoveries from the far side of the moon.
Called the Dark Ages Polarimeter Pathfinder, or DAPPER, the upcoming mission aims to record, for the first time, low-frequency radio waves emitted during the earliest epochs of the universe when stars, black holes, and galaxies were just beginning to form.
Charting a new budget-friendly path to the moon
Diagrams showing a NASA-patented trajectory to the moon's orbit that balances both fuel consumption and speed for a small spacecraft. <p class="copyright"><a href="https://technology.nasa.gov/patent/TOP2-272" rel="nofollow noopener" target="_blank" data-ylk="slk:NASA" class="link rapid-noclick-resp">NASA</a></p>
Diagrams showing a NASA-patented trajectory to the moon's orbit that balances both fuel consumption and speed for a small spacecraft.
NASA
When NASA launched three astronauts to the moon in 1968, it took the crew just a few days to get there. Such direct shots are expensive, though, requiring an enormous rocket to climb out of Earth's deep gravity well.
There are far more efficient paths to the moon that can use smaller rockets if you have time to spare, which robots do. By taking time to swing around the Earth, for instance, a spacecraft can steal some of the planet's momentum and slingshot out to the moon in a series of long orbits that cost it little to no fuel. Fuel remains necessary to correct orbits and maneuver through space, yet every ounce a spacecraft carries is mass that an engineer can't dedicate toward other components, including scientific instruments.
The calculus is especially tricky for compact spacecraft like DAPPER, which would be about the size of a microwave, since there is (quite literally) less margin for error. Faced with the extra challenge of trying to fly DAPPER on a relatively thin $150 million budget from NASA's Explorers program, the team behind the mission concept realized they couldn't buy their own rocket ride all the way to lunar orbit.
"This trajectory to the moon arose out of necessity, as these things often do," Jack Burns, an astrophysicist at the University of Colorado Boulder and leader of the DAPPER mission, told Business Insider. "We needed to keep the launch costs low and find a cheap way to get to the moon."
They started with a flight they knew they could afford: one to geosynchronous or high-Earth orbit, which is a region about 22,236 miles away from Earth's equator (about one-tenth the way to the moon). It's a common destination for telecommunications and other satellites built to hover above one spot on the planet. DAPPER is small enough to piggyback on such missions.
"If we could just get a launch into high-Earth orbit, geosynchronous orbit, then we could get the rest of the way there with only a modest tank of fuel," Burns said.
After crunching the numbers, the team found a new low-energy trajectory to the moon, which their patent describes as a "method for transferring a spacecraft from geosynchronous transfer orbit to lunar orbit." It enlists the help of Earth and the moon's gravity to speed up and slow down DAPPER at the right moments, cutting down on the amount of propellant required. NASA says this new spin on the gravity assist keeps the flight time to about 2.5 months, whereas similar options can take six months.
The trajectory also comes with numerous options to slip a spacecraft into an orbit of any angle around the moon, at practically any time. And it avoids a zone of radiation around Earth called the Van Allen belts, which can damage sensitive electronics.
Why NASA is patenting and licensing ways to reach the moon
A view of Earth from the moon captured by an Apollo 8 astronaut in 1968. NASA calls the famous image "Earthrise." <p class="copyright"><a href="http://www.nasa.gov/multimedia/imagegallery/image_feature_1249.html" rel="nofollow noopener" target="_blank" data-ylk="slk:NASA" class="link rapid-noclick-resp">NASA</a></p>
A view of Earth from the moon captured by an Apollo 8 astronaut in 1968. NASA calls the famous image "Earthrise."
NASA
It may seem odd to patent lunar travel, but Burns said it is really no different than any other invention. "It's a creation that was the result of doing numerical modeling of planetary trajectories. So it is intellectual property."
NASA patents and licenses inventions as a means of achieving the "widest distribution" of a technology, executive Dan Lockney told IPWatchdog in 2018. "Securing patents and licensing the technologies is a method NASA and other government agencies use to ensure access to government-funded innovations," Clare Skelly, a NASA spokesperson, told Business Insider in an email.
The agency charges as much as $50,000 to license its patents, but typically asks for between $5,000 and $10,000, plus royalties. "It is through the upfront fees that NASA seeks to recover some of its investment in the patent filing and maintenance costs," the agency's licensing website states. In other words: Doing the grunt work of patenting, then charging a minimum for that work, is a formal and industry-compatible practice of disseminating the fruits of NASA's labors.
Unofficially, NASA's scheme also keeps private companies and foreign nations from stockpiling important space technologies for exorbitant sums, and that helps foster American missions and international collaborations. (The agency does occasionally release patents into the public domain.)
For his part, Burns said he doesn't believe NASA will "ever make any money" off the new trajectory patent, since it's often a matter of historical record-keeping.
"It just is a marker that lays down that this was your intellectual property: You did this, and you were the creator of it, so that at least when people use it, they give credit," he said.
Two Nobel Prizes may await in the lunar 'cone of silence'
The purple region shows the lunar "cone of silence" for radio waves. <p class="copyright"><a href="https://dx.doi.org/10.1016/j.asr.2020.05.050" rel="nofollow noopener" target="_blank" data-ylk="slk:Neil Bassett et al.; Advances in Space Research" class="link rapid-noclick-resp">Neil Bassett et al.; Advances in Space Research</a></p>
The purple region shows the lunar "cone of silence" for radio waves.
Neil Bassett et al.; Advances in Space Research
The goal of DAPPER is to study the universe from a "cone of silence" on the far side of the moon. In that solitary region, humanity's cacophony of wireless emissions can't interfere with antennas trying to pick up weak, low-frequency emissions from more than 13 billion years ago.
"This is the only truly radio-quiet region in the inner solar system," Burns said. Humanity's pollution of radio waves which leak out of almost every electronic device can easily bend around corners and over horizons (so erecting barriers to block them is fruitless). "In order to get the same amount of quiet, you'd have to go out past the orbit of Jupiter, and go that far out in order for the noise just from Earth."
Specifically, the mission seeks to detect radio emissions of the "neutral hydrogen" that dominated the very early universe. The cosmos produced the nuclei, or cores, of these first-ever atoms within a microsecond after the Big Bang; the event's dense, hot soup of energy had expanded and cooled off, permitting protons, neutrons, and electrons to form. About 380,000 years later, the soup of particles had cooled off further, allowing the positively charged protons to capture negatively charged electrons and become neutral hydrogen atoms.
The phase is often called the "Dark Ages" because, in visible wavelengths of light, a human wouldn't have seen anything.
"There's no stars. There's no galaxies. There's no other source of radiation. So how do you probe that part of the universe?" Burns said. "You use the one thing that you've got a lot of, which is neutral hydrogen."
The problem is that those radio signals, which reach Earth in the 10-100 Mhz range, are not only scrambled by our planet's atmosphere, but match the emissions of countless power supplies, garage door openers, radio transmitters, space satellites, digital TV signals, and more.
"The radio spectrum down at these frequencies? It's just absolutely filled with garbage," Burns said.
Even in space, there's so much interference from humanity and the sun that Burns said the radio-equivalent temperature around Earth is "nearly a million degrees."
By slipping behind the moon at a moment when the sun is blocked as well as Earth, DAPPER is expected to make the first clear recordings of neutral hydrogen signal. The spacecraft might also gather evidence of the first stars, and possibly the first black holes and galaxies that formed about 500 million years after the Big Bang, during an epoch called "Cosmic Dawn."
And maybe just maybe the spacecraft could turn up the first direct detection of dark matter, which makes up about 80% of the mass in the universe but has yet to be identified.
"Several people have told me there are at least two Nobel Prizes here. One is, you're detecting when the first stars and galaxies form and what they are. And number two, you're detecting dark matter," Burns said. (He pooh-poohed the idea of winning the prize himself.)
The race to the early-universe radio emissions is on
<p class="copyright">NASA</p>
NASA
Burns and others came up with the Dark Ages Radio Explorer (DARE) lunar mission about 10 years ago, which is why that mission, and not DAPPER, is described in the patent, which NASA filed in 2015. (The USPTO is a notoriously slow-moving federal organ.)
Burns said NASA was excited about DARE no one had ever done something like it before but noted the agency was bound by rules that favored established science and hardware over newer approaches.
"There is no history of low frequency experiments in space. So, on the one side, people are excited: 'Wow, you're opening up an entire new field of cosmology. This is great. This is fantastic. You need to do it,'" Burns said. "The other side is, 'Well you've never done it before, so it must be risky.' And so you get marked down for the risks."
After years of being passed up, Burns and his colleagues decided to shrink the car-size spacecraft down to its current size, ditch novel hardware for well-proven "heritage" technologies, and try again.
The gambit is working. Over the past few years, NASA has awarded DAPPER a few million dollars to prove out the mission's concept and mature its hardware design to a flight-ready state. When that work concludes within two years, DAPPER will have a good chance of winning $150 million from NASA's Explorers program funding that'd get a spacecraft built and a rocket ride booked, should DAPPER have to purchase one from SpaceX, United Launch Alliance, Blue Origin, or some other provider.
Burns isn't sure the mission will require the new patent to reach lunar orbit. In the years since his team came up with it, commercial rocket providers have started planning semi-regular launches to the moon. NASA is also working toward the launch of its massive Space Launch System rocket, which could easily carry DAPPER on a flight in the mid-2020s.
"The possible ways to get there have widened considerably since this orbital trajectory was first designed," Burns said.
But time is growing short. There is a growing push to land humans (and their noisy electronics) at the moon's poles, including an effort by China. That nation's space agency has also landed spacecraft on the lunar far side, where its robots are exploring the surface for the first time.
"Given how simple we have made the DAPPER instrument now, a lot of people could build it. A lot of countries, even individual companies, could build this," Burns said. "Every so often I see a paper coming out of China with my figures in it, and they're talking about their own mission."
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