Five months after a tilt-a-whirl spin spoiled the debut of Starfish Space’s first spacecraft, the Tukwila, Wash.- based startup has halted efforts to put its Otter Pup back on track to demonstrate an on-orbit satellite rendezvous.
Starfish had to abandon its plan to regroup and attempt a rendezvous when the Otter Pup satellite’s electric propulsion thruster suffered an anomaly and could no longer function. “We determined that we just pushed it a little bit too far,” Starfish co-founder Austin Link told GeekWire.
The months-long drama began shortly after Otter Pup’s launch aboard a SpaceX Falcon 9 rocket in June, when the satellite and the space tug to which it was attached were sent out into low Earth orbit. Launcher’s Orbiter SN3 space tug experienced an anomaly that set it spinning at a rate of nearly one revolution per second, far outside the bounds of normal operating conditions.
Mission managers deployed Otter Pup immediately on an emergency basis, but Starfish’s spacecraft kept spinning even after it separated from the tug. Link and the rest of the Starfish team worked for weeks to stabilize Otter Pup, and in August they drew up a revised plan to rendezvous with a spacecraft to be named later.
Starfish put Otter Pup through a round of tests to make sure the spacecraft was healthy. Then the team executed a series of maneuvers with the spacecraft’s Exotrail Hall-effect thruster, which uses xenon as a propellant.
Link said the electric propulsion thruster fired multiple times over the course of multiple weeks — for as long as 90 minutes at a time, adding up to a cumulative total in excess of 15 hours. But a few weeks ago, the thruster didn’t fire when commanded to do so. Efforts to get the thruster working again went nowhere.
“There’s nothing destructive about the anomaly,” Link said. “The satellite is still communicating with us and power-positive, and we’re actually actively running tests on it currently. The satellite just doesn’t make thrust anymore.”
Starfish and Exotrail haven’t yet identified root cause of the anomaly but are continuing the investigation.
“The overall conditions of our mission have been stressing for the thruster, and the maneuvers that we were performing were beyond the expectation of what the original mission would require,” Link said. “There is still xenon that remains, so we know that propellant is not the issue.”
Exotrail’s co-founder and CEO, Jean-Luc Maria, told GeekWire via email that “the issue occurred after a successful commissioning and several hours of nominal firings.” He noted that “very cold temperatures, outside of the specification / qualification envelope, have been monitored at the thruster head level.”
Although it will no longer be possible to demonstrate rendezvous and docking with a target spacecraft, Starfish’s first space mission is far from over. “We’re fortunate in that we’re still able to run a lot of tests in orbit,” Link said.
Eventually, atmospheric drag will be Otter Pup’s downfall. “It will deorbit naturally, just due to orbital decay, from Earth’s extended atmosphere in roughly about five years,” Link said.
Starfish Space is already getting ready for the next mission. “We are building a second Otter Pup, and have been since the week after Otter Pup was initially separated, spinning at 330 degrees per second,” Link said. “It will use a very similar design to the first Otter Pup. This includes an Exotrail thruster, and we are excited to continue to work with Exotrail.”
The second Otter Pup mission will be funded internally, Link said. (For what it’s worth, in March, Starfish reported raising $14 million in a Series A funding round.) Launch is tentatively planned for the end of 2024.
Link pointed out that both Otter Pup missions are meant to lay the groundwork for a larger-scale Otter spacecraft that could rendezvous and hook up with other satellites in orbit — either for servicing and refueling, or for deorbiting.
“We’ve learned a lot from the Otter Pup 1 that will help us better do life extension and satellite disposal missions,” he said.
He acknowledged that the past few months have been an emotional roller coaster for Starfish’s workforce of roughly 45 full-time employees. “You feel the excitement of all of the highs — the initial launch, the recovery from the spin, some of the tests that we’ve been able to run and showcase on orbit,” Link said. “And you feel the emotional lows of losing a mission that a lot of us have put a lot of effort into over the last couple of years. Those emotional lows are really tough when it’s a mission that means a lot, not just to the company, but to a lot of us as individuals.”
But even amid the lows, Link and his teammates retain their sense of humor.
“We’ve chuckled a couple of times that it’s too bad that Starfish Space doesn’t really exist at scale today,” he said, “because something like the Otter could go help us save the Otter Pup right now.”
