Atomos Space’s first orbital mission is a fire test

Few missions exemplify the adage “space is tough” more than Atomos Space’s first demonstration mission, with the company successfully pulling back from the brink of disaster more than once.

The demonstration mission, known as Mission-1, was launched into orbit on March 4 on a SpaceX Falcon 9 rocket. The goals of the mission are very ambitious: Two spacecraft – an orbiting transfer vehicle called Quark-LITE and a target vehicle called Quark-LITE Gluon – will eventually demonstrate extremely complex maneuvers, including rendezvous, docking , orbital transfer and on-orbit refueling.

The company faced two major problems related to communications and the speed of the spacecraft’s rotation, which it (largely) solved despite huge limitations, infrequent data packets and extremely limited bandwidth . (So ​​limited, in fact, that the team had to limit its flight software updates to text strings just 145 characters long.)

“It’s relentless,” Atomos CEO and co-founder Vanessa Clark told TechCrunch.

William Kowalski, the company’s chief operating officer and co-founder, agrees. “Even in our case, we were trying to infer the state of a very complex system from 100 bytes of data, which made it so difficult,” he said. “There’s a lot, and you’re guessing what’s driving this because you know some of that guessing could put you on a path that you’ll never recover from.”

The problems began just hours after the two docked spacecraft deployed from the Falcon 9 upper stage. The deployment was nominal, and Atomos received its first ping from the spacecraft seven minutes after deployment. The atmosphere is celebratory.

But 40 minutes passed and the company received the next ping. Then eight hours.

Atomos expects to receive packets every few minutes.

“the worst [day] That night was our launch Monday,” Kowalski said. “It was 11 o’clock at night, and the chief engineer and I… we didn’t hear anything, we were just thinking, did we fail? Are they dead? We tried and we didn’t succeed. It was a real punch. “

It took mission controllers 24 to 48 hours after deployment to determine the root cause, which they did with the help of another company with assets in orbit. After some effort, they got on the phone with the chief systems engineer at satellite communications company Iridium. In addition to using the Iridium constellation as a relay satellite, the spacecraft also uses a third-party modem to take advantage of Iridium’s inter-satellite link network. Atomos’ spacecraft are moving too fast and in opposite directions, so they can’t perform a data “handshake” with those Iridium satellites to actually transmit the information back to Earth.

Atomos engineers eventually rolled out a series of software updates to reduce load cycling and ensure the radio was always on, even when the spacecraft was in a low-power state.

However, when engineers tried to solve the communication problem, they faced a different problem: the spacecraft rolled at an extremely fast speed of 55 degrees per second (they are designed to handle roll speeds of up to 5 degrees per second). Additionally, the spacecraft is slowly rotating so that the solar arrays are no longer facing the sun. That means it’s a race against time and a race against completely draining the spacecraft’s batteries.

“We have two charts,” Kowalski said. “We plotted our power trends as we thought we would be farther away from the sun and affected. [at] Zero power and our roll rate. It is reducing the roll rate to zero before the power goes to zero. “

This problem is exacerbated by limited communications. It wasn’t until the fourth day after deployment that the team was able to definitively confirm something was wrong, and the spacecraft was able to digest new commands during the long communications outage.

Slowly, over several days, they were able to slow the spacecraft down. The team achieved another major victory by successfully establishing high-bandwidth communications, an air-to-air link on Quark-LITE communicating over the Inmarsat network. The company made its first attempt to access high-bandwidth communications on Thursday and successfully maintained communication with the spacecraft for six minutes.

During this period, mission controllers received 17 times more data than since launch. This provides mission controllers with a wealth of data about the health of the spacecraft. Not all the news is positive — one of the battery packs on the OTV took a serious hit from a vigorous ride, and the GPS on one of the spacecraft appears to need to be reset — but those are easily fixed, Clark said.

The company plans to start commissioning the propulsion system on Tuesday or Wednesday. If all goes according to plan, and engineers can determine that the propeller system is capable of providing pointing accuracy and control, they will test operation with the torque rod and reaction wheel turned off. The company aims to separate the spacecraft in about a month, with the goal of completing all mission objectives by the end of June.

Kowalski and Clark attribute part of the startup’s success to its high degree of vertical integration. The team, which worked 100-hour weeks in the first week of deployment, was able to use its deep knowledge of spacecraft design to solve problems as they arose.

“It’s obviously very painful, but it’s like the CEO of Nvidia said: ‘I wish you tremendous pain.'” We’ve been through this, and it wasn’t great at the time, but now we’re through it After the most difficult period, we are definitely more accomplished,” Clark said.