Critical Moment and Backup Plan
When the satellite communications failed on NASA’s Super Pressure Balloon-borne Imaging Telescope, SuperBIT, the team found themselves in a precarious situation. They had gathered valuable astronomical imaging data from above 99.5% of the atmosphere, and losing it would be devastating. But the team had a backup plan, and it involved dropping the entire telescope, along with its data, to the ground by parachute. It was a risky move, but they were determined to salvage their hard-earned data.
Challenges in Recovery
The SuperBIT team had been circling the southern hemisphere, mostly over the ocean, and they knew that their opportunities for recovery were limited. Their best chance was the upcoming landfall over Argentina on May 25, 2023. By simulating windspeeds and weather patterns, they were able to make an educated guess about where the instrument would land.
Unfortunately, things didn’t go as planned. After the telescope touched down in a remote part of Santa Cruz province in Argentina, the parachute failed to disengage. To make matters worse, the wind dragged the instrument for 3 kilometers across the rugged Argentinian wilderness, leaving a trail of debris in its wake.
A Daring Backup Plan
But the team wasn’t ready to give up just yet. They had a backup plan for their backup plan, and it was a daring one. Ellen Sirks and Richard Massey, along with the rest of the SuperBIT team at Durham University in the UK, share the story of this mission and propose that other balloon-borne missions could adopt a similar approach to mitigate the risk of failure.
SuperBIT Mission Overview
The SuperBIT mission began on April 16 with a launch from Wanaka, New Zealand. The telescope soared to an altitude of 40 kilometers and spent the next 40 days observing distant galaxy clusters in the hopes of capturing gravitational lensing events that could provide evidence of dark matter. The mission generated a high rate of data, so the telescope was equipped with two downlinks for communication and also stored onboard copies of all the data as a backup.
Communication Challenges
On May 1, the Starlink connection was lost for unknown reasons. Then, on May 24, the TDRSS system started to fail, putting the entire mission in jeopardy. Faced with the possibility of losing everything, the team made the difficult decision to bring the instrument back down to Earth, ultimately leading to its destruction.
Ingenious Backup System
However, the team had prepared for such a scenario. The telescope was designed with four capsules, each equipped with a small parachute. These capsules contained Raspberry Pi circuit boards connected to microSD cards that held complete backups of the mission data. They also had GPS receivers, batteries, and satellite communication systems to broadcast their locations. The capsules were designed to be released from the telescope using a servo-operated pincer mechanism.
Challenges in Capsule Deployment
During the mission, one of the capsules malfunctioned, possibly due to a disconnected data cable during launch. But three capsules remained as backups. With the telescope hanging from a helium-filled balloon at an altitude of 33 kilometers, the team dropped two of the remaining capsules over Argentina. They calculated the terminal velocity of the parachuting capsules and considered the local wind patterns to determine where they would land. Their goal was to choose isolated locations to prevent injuries on the ground while still making retrieval feasible.
Capsule Retrieval Challenges
However, things didn’t go smoothly during the descent. The capsules were supposed to broadcast their positions, but their batteries had become frozen and couldn’t supply enough power. This meant that the capsules didn’t report or record their locations as intended. It was a setback, but the batteries warmed up after landing, and the capsules started broadcasting their positions. One capsule landed 2 kilometers further than predicted, while the other landed 2 kilometers earlier. The search and rescue team managed to locate one of the capsules, which was found 24 kilometers from the main road. The other capsule was discovered in a snowy area surrounded by cougar prints, suggesting that the wildlife found it intriguing but not appetizing.
Data Recovery and Conclusion
Both capsules contained complete copies of the mission’s data set. The team was able to verify the integrity of the data by comparing it to the intact solid-state drive found in the debris field. The Data Recovery System capsules had proven to be a resounding success, ensuring the scientific returns of SuperBIT despite the loss of communication and the destruction of the telescope.
Lessons Learned and Future Recommendations
This remarkable story carries an important message. By investing in relatively inexpensive backup systems, the team was able to safeguard their scientific data against unforeseen events. They recommend that future balloon missions consider implementing similar systems to mitigate the risk of failure.
Historical Context
It’s worth noting that SuperBIT was not the first mission to use parachutes for data collection. In the 1960s, the first US spy satellites used parachutes to return photographic film of Soviet military facilities. These film capsules were caught mid-air by specially equipped aircraft over the Pacific Ocean. While the current generation of spy satellites no longer relies on parachutes, the concept of using parachutes for data retrieval has a long history.
Final Reflection
In conclusion, the SuperBIT team’s experience serves as a valuable lesson for future missions. By planning for contingencies and implementing backup systems, scientists can ensure the preservation of their valuable data. The story of SuperBIT’s data recovery is a testament to the ingenuity and resilience of the team, and it opens up new possibilities for balloon-borne missions in the future.
Photo: Freepik.com
