This week in Rocket History, we have a carryover from last week, but that’s ok because as always, this launch happened roughly around this week in history.
On February 22, 2019, a SpaceX Falcon 9 Block 5 launched from Cape Canaveral in Florida, carrying two payloads: an Indonesian telecommunications satellite called Nusantara Satu, or PSN-6, and a tiny two-meter by 1.5-meter lunar lander by the name of Beresheet, which means “in the beginning” and is also the Hebrew name for the book of Genesis.
The lunar lander was designed by a nonprofit organization called SpaceIL, with the help of Israel Aerospace Industries, as part of the Google Lunar X-Prize competition, which saw teams from all over the world compete to get a lander to the surface of the Moon without any government assistance. The competition’s original deadline, which was the end of 2014, kept getting extended until late-2018 when Google pulled their sponsorship along with the thirty million dollars of prize money, and the competition was officially canceled. That however did not stop SpaceIL from launching their Moon shot, as they had already purchased a seat for Beresheet on the Falcon 9.
The Falcon 9’s second stage pushed the little spacecraft all the way up to an altitude of around 700 kilometers. Moments after its release, the control center at Yahud in Israel started receiving telemetry.
Beresheet’s initial orbit was a highly elliptical transfer orbit with a lowest altitude (or perigee) of 320 kilometers, and a highest altitude (or apogee) of 69,400 kilometers.
Almost immediately after separation, Beresheet performed its first big feat: deploying its struts. The landing legs extended as planned, but immediately ground control noticed something weird: the star trackers, special cameras designed to track stars to determine Beresheet’s orientation in relation to the Earth and the Moon, were completely blinded by the Sun reflecting off of the golden insulation of the landing struts.
The engineers had to reprogram the spacecraft to only use the star trackers when sunlight was not directly reflected off the struts and to use the accelerometers to try and track the spacecraft’s orientation at other times. And while that solution partially worked, it was a bit inaccurate.
A day later, on February 23, Beresheet ignited its British-built LEROS 2b main engine for the first time and raised its perigee to an altitude of 600 kilometers.
On February 24, two days after launch, Beresheet was supposed to perform its first big apogee-raising maneuver, but seconds before starting the critical burn, the spacecraft’s computer froze and had to reboot itself, which automatically canceled the maneuver. This problem continued to plague the mission and was probably due to damage suffered by an electronics box caused by the high levels of radiation the spacecraft had to go through.
On Beresheet’s next orbit, however, the maneuver was performed without a glitch, igniting and burning for thirty seconds, raising the spacecraft’s apogee to 117,000 kilometers.
Three more burns would be performed until the final apogee-raising maneuver on March 19, which brought Beresheet’s apogee to around 405,000 kilometers, crossing the Moon’s orbital path.
On April 4, 2019, Beresheet encountered the Moon and performed a lunar insertion maneuver, which means it had to slow itself down compared to the Moon so that the Moon’s gravity could capture Beresheet and change its orbit to be around the Moon rather than around the Earth.
The maneuver went smoothly, and Beresheet ended up in an elliptical orbit with a closest approach, or perilune, of 500 kilometers and a farthest point, or apolune, of 10,000 kilometers from the Moon’s surface. Just a few days later, Beresheet would perform small maneuvers to circularize its orbit at an altitude of 200 kilometers, in preparation for landing.
On April 11, after a series of altitude lowering maneuvers, Beresheet started its final landing burn, which was supposed to slow it down and lower it to the surface of the Moon for a soft touchdown. During the descent, however, one of two inertial measurement units, or IMUs, reported a malfunction. Mission control had to decide whether to continue with just one IMU, which was possible, or to restart the failed one in an attempt to regain redundancy. The call was made to restart the faulty IMU. Unfortunately, that caused a chain reaction which ended up in both IMUs appearing offline, something Beresheet was not designed to handle.
This caused the spacecraft’s computers to reboot, shutting off the engines which, up until now, had been gradually slowing the craft’s descent. By the time the computers could recover and load all of the updates telling the craft to ignore the previously failed sensors, it had too much speed to shed and eventually crashed into the surface of the Moon at a speed of 946 meters per second.
About a month later, NASA’s Lunar Reconnaissance Orbiter found the crash site, but Beresheet was so lightweight, it did not even create an impact creator, just a smudge.
In the months following the crash, SpaceIL revealed that the mission had been in far worse condition than originally disclosed.
From the moment the star trackers were blinded, the command center had to frequently upload software updates to the spacecraft. Because of the way the craft’s systems were designed, each time the computer rebooted, which ended up being often, the software updates had to be loaded again after boot, which would take a few seconds.
As a result, even though the spacecraft could handle one failed sensor, it could not handle a multitude of them. Once the gyro went offline during landing and the spacecraft was rebooted, the torrent of resulting alarms caused the last, fatally-timed restart as a security measure.
In an interview with the Davidson Institute, Ido Anteby, SpaceIL CEO during the mission, said: The spacecraft wasn’t designed to withstand two separate malfunctions; otherwise, it would have cost $1 billion instead of 100 million.
It was also later revealed that for long periods of time during the mission, ground control had virtually no idea where Beresheet was and could not communicate with it; the antenna was so low-powered that they lost the signal shortly after its last apogee raising maneuver and could only assume where it was based on previous predictions.
Luckily, NASA gave SpaceIL access to its Deep Space Network, an array of very powerful radio antennas spread across the world used to communicate with very far away spacecraft, which managed to locate the faint signal from the tiny lunar lander and restored communications with it just before it was time for the lunar insertion maneuver.
All things considered, given its extremely low budget, its team comprised mostly of volunteers, and the production and in-flight hurdles it overcame, Beresheet actually got really close to achieving its secondary mission of landing on the Moon, while its primary mission was considered a resounding success. You heard that right – Beresheet’s primary mission was not, in fact, to land on the Moon.
SpaceIL’s mission is to promote science and science education and to inspire a new generation of scientists through an “Apollo Effect”, so named after the sharp rise in STEM majors following the Apollo landings. To inspire an entirely new generation of kids to go into STEM would require a feat as remarkable as landing on the Moon. And that was the real purpose of Beresheet: to inspire. And that it did.
From the moment of its conception, SpaceIL focused primarily on science education. Hundreds of volunteers gave thousands of presentations all around Israel and the rest of the world, mostly but not exclusively to children, telling them about the daring mission to put a small, privately funded, Israeli spacecraft on the surface of the Moon.
One final fact about Beresheet: like many space probes launched over the last few years, if not decades, it carried some other non-science payloads. Onboard Beresheet, SpaceIL included a large disc engraved with microscopic texts and images, including the Hebrew Bible, drawings from Israeli school children, and pictures selected by SpaceIL volunteers, including a picture of our own Dr. Pamela Gay and Fraser Cain, added at the request of one of the volunteers who happened to be a fan of Astronomy Cast.
And just because it didn’t successfully land on the Moon doesn’t mean the story stops here. On December 9 of last year, SpaceIL announced a plan for Beresheet 2, a mission that will consist of a lunar orbiter carrying two much smaller landers. It will also carry experiments designed by school children from Israel and other countries and is intended to launch in 2024. We can not wait to see the amazing things it will achieve.
Google Lunar X-Prize (Wikipedia)
Computer reset cancels orbit-raising burn on Israel’s moon lander (Spaceflight Now)
What Happened to Beresheet? (Davidson Institute of Science Education)
IAI press release