Jan 2, 2019 · 49m · a16z
a16z Podcast | New Year, New Horizons -- Pluto!
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
In this episode of the a16z Podcast, host Frank Chen and senior scientist Ivan Linscott explore the groundbreaking radio science, extreme hardware engineering constraints, and high-stakes operational crises behind NASA's New Horizons mission to Pluto and the restoration of the historical Stanford Dish antenna.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. The host holds 1.6% of the talking time here. How this is scored →
The host as informed peer 1.1 Guest teaching 6.0 Guest disagreement 0.1 The host pushing back 0.0
speaking balance: gold is the host, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 6:07 Gentle correction on space distance record
Ivan politely reframes Frank's prompt by pointing out that Pioneer spacecraft are actually further away than New Horizons, though New Horizons set distance records for specific experiments.
Hardest push from the host ▶ 7:09 Re-framing power budget using PC hardware termsIn an entirely collaborative interview, Frank's clearest moment of asserting a perspective is re-framing the 250-watt power budget by comparing it to an entry-level desktop computer power supply.
Biggest teaching moment ▶ 22:12 Explaining space-qualified code disciplineIvan explains why brilliant PhD students fail at FPGA hardware design by over-optimizing code, requiring a veteran programmer's strict coding discipline to fit the design into remaining gates.
The host holds their own ▶ 7:09 Relating satellite wattage to consumer electronicsFrank demonstrates domain knowledge by translating abstract spacecraft power specifications into practical desktop computer and lightbulb energy equivalents.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | The host as informed peer | Guest teaching | Guest disagreement | The host pushing back | Why |
|---|---|---|---|---|---|---|
| How Frank Chen Met Ivan Linscott | 1 | 5 | 1 | 0 | Frank welcomes Ivan and asks warm introductory questions about his career path and the radio science experiment. Ivan details his trajectory through SETI, Stanford, and radio occultation, gently correcting Frank's assumption about flight distance records. | |
| Powering New Horizons with Plutonium RTGs | 2 | 5 | 0 | 0 | Ivan explains how plutonium radioisotope thermoelectric generators power the spacecraft. Frank offers a domain comparison to computer power supplies, while Ivan educates on power constraints and isotope degradation. | |
| Brokering Russian Plutonium and Launch Pressure | 1 | 6 | 0 | 0 | Ivan details the geopolitical race to secure fuel after a Department of Energy facility leak threatened launch windows. Frank listens in awe as Ivan describes brokering Russian nuclear material via the State Department. | |
| The Single FPGA Constraint and Breakthrough | 1 | 7 | 0 | 0 | Ivan outlines the extreme engineering constraints of fitting complex digital signal processing into a single radiation-hardened FPGA. Frank follows along as Ivan describes vacuum-tube-inspired filtering algorithms and saving the design with five remaining gates. | |
| Signal Transmission Dynamics Across Billions Miles | 1 | 7 | 0 | 0 | Ivan explains the mechanics of long-distance communication across billions of miles using Deep Space Network stations and ultra-stable oscillators. Frank prompts for details as Ivan breaks down signal-to-noise ratios and quartz clock accuracy. | |
| Cold War Submarine Espionage and Oscillator Sourcing | 1 | 6 | 0 | 0 | Ivan shares a Cold War submarine espionage story to explain the origin of ultra-stable oscillators and the supply shortage faced by the Pluto mission. Frank acts purely as an engaged audience for Ivan's historic anecdotes. | |
| Safe Mode Emergency Before Pluto Encounter | 1 | 6 | 0 | 0 | Ivan describes the safe-mode anomaly right before the Pluto flyby caused by a JPEG compression race condition on starfield imagery. Frank interjects with dramatic prompts while Ivan explains the rapid recovery process. | |
| History and Battleship Hydraulics of Stanford Dish | 1 | 6 | 0 | 0 | Ivan recounts the history of the Stanford Dish and its unusual drive mechanism built using surplus WWII battleship anti-aircraft hydraulic motors. Frank asks about local history while Ivan explains the engineering risks. | |
| Stepper Motor Retrofit and Satellite Forensics | 1 | 6 | 0 | 0 | Ivan explains how hard drive stepper motors revived the dish to track silent, broken satellites via faint oscillator leakage. Frank wraps up the interview praising the remarkable engineering stories. |
Statements from this episode (16)
Pluto's night side is significantly warmer than its day side
“Discovered some really quite surprising things, like the day, the night side is a whole lot warmer than the day side”
New Horizons conducted the most distant radio occultation and radar experiments
“This is the furthest radius occultation experiment that's ever been done, and the furthest bi-static radar, furthest radar experiment that's been done.”
NASA's New Horizons spacecraft runs on 250 watts of plutonium power
“We use a radioactive element called plutonium to generate the heat, and that generates about 250 watts for us of power.”
A radioactive leak halted DOE plutonium fuel production for New Horizons
“In our case, that process got started. There's a plutonium processing facility that the U.S. Department of Energy maintains, and that there was in about halfway through the process, there was a leak that was discovered in the radioactive leak, and they shut do…”
A Jupiter gravity assist shortened New Horizons' Pluto transit by years
“We were looking for a gravity assist at Jupiter, which would have boosted the, which did boost the arrival time by about four or five years.”
The U.S. bought half of New Horizons' plutonium fuel from Russia
“Glenn, brokering through the U.S. State Department, Got the U.S. To make an offer to the Russians to buy their plutonium for this mission... For the missing piece of it. It wasn't the entire piece, but it was about half.”
New Horizons required nuclear licensing in six months instead of years
“The last time that that happened for the Cassini mission, the license itself took like three years, maybe five Pushing four. And we had to have it in under six months.”
NASA mandates a 15% to 25% FPGA gate margin for spaceflight
“NASA guidelines is you need at least, we would like you to have a 25% margin. Minimum number is 15%, which means 50% of a million gates, 150,000 gates just sitting there unused.”
New Horizons flew to Pluto with only five unused FPGA gates
“He had five. Five gates left. And that's the way we flew.”
New Horizons achieved a million-to-one signal-to-noise ratio at Pluto
“We've sent 20,000 watts on an aperture that's about 70 meters in diameter, so the instantaneous power in the beam is huge. It's over a million watts per square meter. At Pluto, which is 3.7 billion miles out, in a system that captures this, those wave forms ar…”
Key ultra-stable oscillator suppliers went bankrupt before the New Horizons mission
“There was a French company that was making them, and they had gone bankrupt. There was a US company that was making them. They'd gone bankrupt.”
Only two of five delivered oscillators met New Horizons specifications
“And so here we are, six months before launch, we have to actually have one of these things to integrate into the payload, and that company delivered five. We tested the five. Two were okay. Two met specs, and they were put on the mission.”
Radio signals between Earth and New Horizons took nine hours round-trip
“Because it's a four and a half hour light travel time. So essentially round trip is nine hours.”
A JPEG compression delay caused New Horizons' pre-flyby safe mode
“It turned out that six months ago, the picture of the sky was dark. There was nothing but black and a few stars, so the JPEG compression took a whole lot less time. It was done when the flash commands came in. This time, it wasn't.”
The Stanford Dish used surplus WWII battleship anti-aircraft hydraulic motors
“And the hydraulic motors that were the best, that were best designed for that were the anti-aircraft gun controls on U.S. Battleships. And after World War II, those were being surplused. And so what they did was they got two of them. Well, maybe they got a few…”