As part of ongoing research into Li-Ion battery cells that can be charged at temperatures below 0C, TDA Research has chosen Pumpkin to aid in developing new 'flavors' of Pumpkin's BM2 intelligent Li-Ion battery that incorporate 18650-size cells with new, advanced chemistries.

One way to test the performance of new cell chemistries at low temperatures is to fly them on high-altitude balloon missions. Working with TDA and TDA's chosen ride — StratoStar — Pumpkin adapted a SUPERNOVA 6U chassis to interface to the StratoStar balloon infrastructure and to provide a complete test platform for charging and discharging the BM2 during flight. This platform utilizes Pumpkin's GUTS flight software (FSW) to provide full end-to-end TT&C as well as to capture telemetry from the entire system during the flight. A Pumpkin EPSM1 was used to dynamically control the flow of power into and out of the BM2 DUT, in order to validate charging (CHG) and discharging (DSG) performance under various environmental conditions during the flight.

Pumpkin's BM2 can be adapted to any Lithium-based cell chemistry, with safety settings (OV, UV, OC, OT, UT, etc.) appropriate for the particular cell chemistry.

It's been a pleasure working with TDA and StratoStar towards this successful mission!

Images courtesy of StratoStar.

On July 23rd 2025 another pair of Pumpkin's PMDSAS Deployable Clamshell Solar Arrays (DCSAs) was successfully launched into orbit, this time on NASA's Athena EPIC spacecraft built by NovaWurks aboard a SpaceX rocket launched from Vandenberg SFB.

The DCSA family of deployable arrays packs tightly and is trivial to integrate and deploy. Over the years, NovaWurks has successfully used Pumpkin DCSAs with increasingly powerful solar arrays in various LEO missions.

Video courtesy of SpaceX.

Pumpkin's BM2 intelligent Li-Ion battery module will fly as part of one or more payloads on NASA's Artemis II mission. As part of mission assurance testing, NASA needed to know whether the BM2 would pass the MIL-Std 461 RE102 (EMI radiated emissions) test should a battery separation inhibit fail, since a failure could conceivably interfere with the mission's range safety devices. To pass the test, the BM2 would have to exhibit radiated emissions well below a prescribed limit, spanning the 200MHz to 18GHz RF range.  Testing was conducted on July 15 at Marshall Space Flight Center (MSFC) in Huntsville, Alabama in a large all-metal-wall EMI test room that utilizes air bladders to seal the metal doors of the room while these sensitive tests are in progress.

The BM2's RBF and Separation inhibits were removed (this simulates a Sep inhibit failure after the host spacecraft has been integrated onto the LV), and emissions were scanned from 200MHz to 1GHz and then from 1GHz to 18GHz. As can be seen from the test plot covering 200MHz to 1GHz, the BM2 easily passed this radiated emissions test, with a considerable margin to spare. This confirms that the multiple processors that make up part of the BM2 architcture (for battery safety and higher-level functions like providing telemetry in engineering units, performing cell balancing and enabling deep sleep modes) have been proven to not interfere with NASA's operational concerns. Pumpkin extends its thanks to the NASA employees and contractors who suggested, managed and performed this EMI test.

MSFC is inside of the U.S. Army's Redstone Arsenal. The U.S. Space & Rocket Center is just outside of the Redstone arsenal grounds, and includes both outside and inside exhibits. Also, Space Camp is located next door. Those of you reading this who are into rockets should plan on visiting the museum -- it's definitely worth a trip.

Images (C) Andrew E. Kalman and/or courtesy of NASA.