# Data Downloaded via Parachute from a NASA Super-Pressure Balloon
## 1 Introduction  
The Super-pressure Balloon-borne Imaging Telescope [1] (superBIT) was raised to \(\sim\)33 km altitude by NASA's 18.8 million cubic foot super-pressure balloon 728 NT ([[https://www.csbf.nasa.gov/map/balloon10/flight728](https://www.csbf.nasa.gov/map/balloon10/flight728) NT.htm]([https://www.csbf.nasa.gov/map/balloon10/flight728](https://www.csbf.nasa.gov/map/balloon10/flight728) NT.htm)). It was launched on 16 April 2023 from Wanaka, New Zealand, was carried east by seasonal polar vortex winds [2], circumnavigated the Earth \(\sim\)5.5 times, then landed in Argentina on 25 May 2023. During this flight, the telescope acquired deep optical and near-UV imaging of galaxy clusters and other astronomical objects [3]. Early in the mission, data were transmitted to ground stations via Starlink and tdrss satellite communication links. However, the Starlink connection was lost on 1 May 2023, and tdrss became unstable on 24 May 2023. The root cause for each failure remains under investigation. All of the data was stored on board, as well as on redundant sets of solid-state drives within drop packages. Several copies of the full dataset were released via parachute prior to the termination of the flight and were safely recovered. The superBIT payload was entirely destroyed upon landing, and although, in this case, the data were eventually recovered from the remains of the onboard drives, the use of parachutes to ensure the safe recovery of the data proved invaluable.  
Four Data Recovery System (Drs) capsules were attached to the telescope before launch. As well as a parachute, each included 5 TB solid state data storage, a Global Navigation Satellite System (GNSS) receiver so it could work out its location, and an Iridium Short-Burst Data (sbd) transceiver, so it could report its location to the recovery team [4] (and receive commands to, e.g., turn on or off a beeper). Two DRSs were released, and both were successfully recovered with data intact.  
In this article, we describe upgrades (since the first test of a DRS during a SUPERBIT engineering flight in 2019) to their release mechanism, communications with the telescope, and thermal control. We describe the performance of that hardware during operations and the performance of software that we use to predict their decent trajectory. Accurate predictions of the descent vector are essential in choosing a safe landing zone. Neither the trajectory of the main telescope payload nor the parachute is actively controlled, but the timing of the release can be chosen so that the DRS lands in an area that is unpopulated for safety but near a road to facilitate recovery.  
Our hardware design ([[https://github.com/[PERSON]/Data_Recovery_System](https://github.com/[PERSON]/Data_Recovery_System)]([https://github.com/[PERSON]/Data_Recovery_System](https://github.com/[PERSON]/Data_Recovery_System))) and software ([[https://github.com/[PERSON]/pyBalloon](https://github.com/[PERSON]/pyBalloon)]([https://github.com/[PERSON]/pyBalloon](https://github.com/[PERSON]/pyBalloon))) are both open-source. Their success inspired nasa's 'Floating dragon' Balloon Challenge ([[https://floatingdragon.nianet.org/](https://floatingdragon.nianet.org/)]([https://floatingdragon.nianet.org/](https://floatingdragon.nianet.org/))). Following this programme, a similar capability to download data or small physical samples will be made available by nasa to all future super-pressure balloon teams to insure against the loss of communications, loss of payload, or destruction of payload upon landing. Our experience suggests that teams should take the offer.