When 6-year-old Libby heard about the plan for the Beresheet spacecraft, Israel’s privately financed bid to send an unmanned lander to the moon, she was worried.
“It’s going to die on the moon, mommy?” she asked. “All alone?”
Actually, if all goes as planned, Libby, Beresheet will never really die. And that may be a problem.
If successful, the craft launched on February 22 is expected to touch down in the moon’s Sea of Serenity on April 11, between the hulking remnants of Apollo 12 and 15 landing modules.
After a few days of experiments, the $100 million craft will become about as useful as an empty tuna can, joining some 400,000 pounds (at Earth weight) of other space junk strewn across the moon’s surface and thousands pieces of bric-a-brac floating above Earth.
Space experts around the world are increasingly concerned about the issue of “space trash,” which includes debris left over from space missions, and, even more worryingly, thousands of defunct satellites still orbiting Earth and creating a massive traffic jam.
The NIS 370 million ($100 million) Beresheet spacecraft is a joint venture between private companies SpaceIL and Israel Aerospace Industries, funded almost entirely by private donations from well-known Jewish philanthropists and launched as Israel’s entry into the Google LunarX challenge for nongovernmental groups to land a spacecraft on the moon. Google ended the contest in 2018 with no winners. With Beresheet, whose name means “Genesis” in Hebrew, Israel hopes to become the fourth country in the world to land a spacecraft on the moon, following the US, Russia, and China.
If Beresheet successfully lands on April 11, the spacecraft is expected to carry out two or three days of experiments collecting data about the moon’s magnetic fields before shutting down. There, all 160 kilograms (350 pounds) of the refrigerator-sized craft will stay, possibly for eternity, on the moon’s surface.
There are no plans to bring it back to earth.
“It’s for our children to figure out how to bring it back,” Dr. Ofer Doron, the general manager of the Space Division at Israel Aerospace Industries, said at a pre-launch press conference in February.
But many believe leaving a mess on the moon for Libby and her friends to clean up is not a solution.
“If you view the environment not only as Earth, but as the entire solar system, we need to be worried about it,” said Professor Pini Gurfil, a professor of aerospace engineering and the director of the Asher Space Research Institute at the Technion in Haifa. “You never know what a piece of junk landed on the moon will have as an impact on future science.”
Dumpster diving on the moon
NASA has a 22-page list [PDF] of all the debris documented on the moon’s surface until 2012, which includes expected material such as batteries, drills, fuel capsules, generators, and camera equipment, and some more surprising items like golf balls, a javelin, wet wipes, multiple urine and defecation collection bags, food assembly packaging, towels, helmets, a hammock assembly system, a rake, 100 $2 bills, nail clippers, and soap. That’s just the trash left by Americans, mostly between 1969 and 1972.
India, Japan, China and the European Space Agency all have lunar orbiters that crashed into the moon, and the Russians are responsible for detritus from 22 lunar missions. A Chinese unmanned spacecraft landed on the far side of the moon in 2013 and stayed.
More surprising items left on the moon include golf balls, a javelin, wet wipes, multiple urine and defecation collection bags, food assembly packaging, towels, helmets, a hammock assembly system, a rake, 100 $2 bills, nail clippers, and soap.
NASA does not consider this detritus to be litter but rather archaeology, a chief NASA scientist told the LiveScience website. Additionally, some of the experiments left on the moon’s surface, including a laser-range reflector, are still being used. Scientists can shoot a laser at the reflector to measure the exact distance of the moon, which helped them realize the moon is moving away from the earth at a distance of 3.8 centimeters (1.5 inches) per year.
Anything left on the moon is expected to stay there a very, very long time, said Gerhard Kminek, a planetary protection officer for the European Space Agency.
Things don’t really decompose on the moon because “there is no real atmosphere on the Moon (just a very, very tenuous [one] called exosphere),” Kminek wrote in an email. So radiation might lead to a partial decomposition of plastic materials, and micrometeorites might pockmark the spacecraft, but Beresheet should stay more or less intact, possibly forever.
Kminek said there are currently no space laws concerning the pollution of the moon. Since the debris stays intact, the question of “contamination” is up for interpretation.
Gurfil considers any piece of man-made debris on the moon worrisome. “[Beresheet] is trying to measure the magnetic field of the moon, but if you have a piece of metal sitting there it can change the measurements or change the composition of soil of the moon or even bacteria [from earth] could affect it, you never know,” he said. The Asher Institute, of which Gurfil is director, provided some consulting to the Beresheet project but was not directly involved.
But NASA scientists argue that the Apollo debris left on the moon has allowed them to measure how materials weather the test of time in space, and in some cases, like the laser reflector, continue to provide valuable data. It is unclear how 50-year-old bags of astronaut feces will be useful to future scientists.
The United Nations Office for Outer Space Affairs (yes, there is an UNOOSA) ratified an international treaty in 1967 governing “the activities of states in the exploration and use of outer space.” The Outer Space Treaty provides the basic framework for international space law, and the last clause is that “States shall avoid harmful contamination of space and celestial bodies.”
Israel ratified the Outer Space Treaty and other, subsequent space treaties, but did not ratify a 1979 Agreement Governing the Activities of States on the Moon and Other Celestial Bodies, which specifically pertains to any activities related to the moon.
Space traffic jam
Space experts, including Gurfil, are actually less worried about the moon debris, and much more concerned over the thousands of defunct satellites still orbiting around Earth.
The European Space Agency is hosting an international convention this week dedicated to exploring the issue of space debris in Germany, with the hope of exploring legally non-binding regulations to govern how countries dispose of satellites launched into orbit, Kminek said.
There are at least 5,000 satellites still in orbit around the Earth, though only 1,950 are still functioning, according to the European Space Association. The Space Surveillance Network tracks about 22,300 objects orbiting Earth, though there are an estimated 34,000 objects 10 centimeters (4 inches) or larger in size, including parts of satellites that have broken off over time.
A collision between a functioning satellite and anything over 10 centimeters (4 inches) in size would completely disable the satellite, but a collision with things as small as 1 millimeter could still destroy certain subsystems of satellites, according to the ESA’s Space Debris Office. There are an estimated 128 million pieces of space debris ranging in size from 1 millimeter to 1 centimeter, and almost 1 million pieces of space debris between 1 and 10 centimeters.
And the amount of space debris is growing. On February 11, 2009, a communication satellite owned by Iridium, a US company, collided with a non-functioning Russian satellite. Both satellites broke apart, creating a debris field of at least 2,500 pieces. These kinds of collisions are only expected to increase.
“The relative speed between satellites is 14 kilometers per second, so any collision will be catastrophic to both satellites,” said Gurfil.
It can seem like there is limitless space in space, but there is actually a fairly narrow window for satellites that need to rotate at the same frequency as the earth, something called geostationary altitude.
The sweet spot is pretty specific: 35,786 kilometers above the Earth’s surface is the exact altitude needed in order for a satellite to move at the same speed as the surface of our planet. This is called “high Earth orbit.”
The high Earth orbit is necessary for things like communication or weather monitoring satellites. At lower altitudes, satellites orbit too quickly; at higher altitudes, too slowly. When a satellite is in the geostationary sweet spot, if you stand in one place and look into the sky, you wouldn’t be able to see it move because it is moving at exactly the same speed as you.
Not all satellites need geostationary altitude. Some, like GPS, can function at a semi-synchronous orbit that takes exactly 12 hours to complete, at an altitude of about 20,200 kilometers, also known as “medium Earth orbit.”
There are thousands of satellites in “low Earth orbit,” including satellites monitoring certain areas or weather systems.
“Too much debris could make some altitudes dysfunctional,” Gurfil said. For example, the altitude of 800 kilometers (500 miles) above earth’s surface is now considered so crowded with satellites and debris that new satellites should not orbit at that level. Even at altitudes that haven’t reached capacity, there are significant risks.
“In a higher orbit, if there’s a collision, there is a risk of the chain effect that could destroy all of the other communication satellites,” Gurfil explained. “It’s called the Kessler effect, and it could be catastrophic to humanity.” If one satellite crashes into another satellite and smashes into smithereens, it could create a chain reaction, with smaller pieces taking out multiple satellites that provide communication, radio, TV, internet, and GPS. “Everything could go down,” said Gurfil. “It’s extremely dangerous. It’s also dangerous to manned spacecraft that could collide with a satellite or satellite pieces.”
The International Space Station has shields against space debris around all of the modules where the crew lives. The shields consist of two sheets of metal with about 10 centimeters of a material similar to bulletproof material separating them. This enables the International Space Station to deflect debris of up to 1 centimeter in size. If there is a risk of colliding with an object larger than 1 centimeter, the space station will maneuver out of the way to avoid the collision.
What goes up costs a lot of money to come down
The major problem is that companies and governments are interested in getting their satellites into space – or their spacecraft onto the moon – at the lowest possible cost. They aren’t planning for how to dispose of them once they become defunct after 20 to 25 years, said Gurfil, and that’s because it costs a lot of money to deorbit a satellite.
Satellites can reduce their altitude to about 400 or 500 kilometers above Earth, at which point they will burn up as they reenter the atmosphere. But doing this requires satellites to carry large amounts of excess fuel in order to change their orbit at the end of their life.
“Every kilo of satellite costs about $60,000 to launch,” said Gurfil. “A few dozen kilos of fuel makes it impractical and not economical to launch the satellite.”
Beresheet, for example, weighs 160 kilograms without fuel, but it weighs 600 kilograms with fuel. That fuel is only sufficient to help the spacecraft land on the moon, but not anywhere near enough to help it return back to earth. Similarly, it is prohibitively expensive to decrease a satellite’s orbit from nearly 36,000 kilometers above Earth to 400 kilometers, Gurfil said.
How do you pick up trash in space?
Space scientists and engineers are now looking at alternative ways to help clear the crowded air around Earth’s orbit. One is to send satellites shooting out even farther into a “graveyard orbit,” at a height that would not affect new satellites launched into the geostationary orbit. “There is also an Israeli startup called Effective Space that offers to build a small satellite that will dock onto satellites and do the deorbiting maneuver for them,” Gurfil said. “This would save the fuel mass and be more economical.”
These days, satellite launch companies like Elon Musk’s SpaceX, which launched the Beresheet satellite and an Indonesian communication satellite at the same time on February 22, make sure that customers who launch a satellite also have a plan for deorbiting the satellite at the end of the its lifespan, which is generally about 20 to 25 years, Gurfil said. The deorbiting mechanism could either be down, so the satellite will burn up in the Earth’s atmosphere, or up, to a graveyard orbit. But there are thousands of defunct satellites still orbiting the earth, some from decades ago, which have no deorbiting plans.
One astronaut’s trash in another astronaut’s treasure
As for Beresheet, the engineers in Israel tried to give the spacecraft’s final resting place on the moon a positive spin by inserting a time capsule with Israel’s Declaration of Independence, the Bible, the memories of a Holocaust survivor, children’s drawings of space and the moon, the Traveler’s Prayer and a note from former president Shimon Peres containing a verse from the Book of Genesis. “Today, we are putting all those dreams in the spaceship, like you would take an note and put it in the Western Wall, wishing for a bright future,” said Yonatan Winetraub, one of three engineers who founded SpaceIL, on December 17, 2018. The engineers inserted the time capsule into Beresheet in a festive ceremony before the spacecraft headed to Florida for the launch.
“It’s a pity, but the trash is going to stay [on the moon], no one will clean it up,” said Gurfil. “Unless you have a lot of fuel that will take the lander back to the Earth, any lander will stay there.”
Aviv Priel, a control engineer at SpaceIL who is in charge of maneuvering the Beresheet spacecraft, bristles at that interpretation. “I wouldn’t call it trash at all,” said Prier. “The thing is, it’s more than several pieces of metal composed together and positioned on the moon.”
“For us, it’s so much more,” Priel said. “It’s not a material. It’s not just a spacecraft. It’s something much more spiritual. We’ve done something that is really impossible. We’ve gathered the whole country to believe in some idea and that’s really difficult to do. It’s really so much more than a spacecraft. It won’t die, because there’s always the idea you can rise up and do the impossible, no matter what your size or what are your resources. You can be bigger and overcome and reach the stars.”
But Libby, age 6, wasn’t quite convinced by Priel’s poetic description of the spacecraft he has worked to build for almost her entire life.
“Why do we need to leave the rocket on its own?” Libby asked. “I want it to come back, so it can go again.”
Libby, along with her younger siblings, drew up plans for Beresheet that include a recycling proposal. “The spaceship has two lasers that will pick up the rubbish, and inside the spaceship is a bin and it will take all the rubbish,” Libby explained on the phone from her bedroom decorated with stars and planets. “Once the lasers pick up the rubbish they will fly it back to Earth, and they’ll take it and build it into robots and other spaceships.”
“If they didn’t leave it, it could come back so we can send it to a different place, like maybe England, because I like England.” said Libby.
“I think they should have had a plan for the spaceship,” she added. “It should take a selfie on the moon, and then it should come back.”