A Little More on the One-Ton to Orbit Class Rockets

We talked about ABL Space, Relativity Space and Firefly Aerospace a couple of days ago.   What I didn't talk about was the leader in that world right now, Rocket Lab and their Electron booster.  Another aspect I didn't talk about is what they can do.

Rocket Lab made the news in a couple of ways in the last few days, including that their next mission in September will be a milestone setter in a couple of ways.  The unexpected and therefore more interesting news was the announcement that they intend to carry out the first privately conducted mission to another planet in history, including funding it entirely.  It will be the first mission to Venus that will sample the Venusian clouds in nearly forty years. 

While the Electron has been quite successful and I've devoted many inches of column space to Rocket Lab, it may not be immediately apparent what we're talking about when we talk about "small satellite launchers."  The Electron is 18 meters tall and can throw all of about 300 kg into low Earth orbit, to be precise.  For comparison, the Falcon 9 is 70m tall, almost four times the height, and can put over 75 times the mass, 22,800 kg, into LEO.  

Since Electron is a small satellite launcher, just how small a payload to Venus are we talking about? The entire Venusian probe will weigh just 20 kg, 44 lbs. The ultimate instrument they want to send will weigh 1 kilogram.  Two pounds three ounces.  

On Tuesday evening Rocket Lab announced that it will self-fund the development of a small spacecraft, and its launch, that will send a tiny probe flying through the clouds of Venus for about 5 minutes, at an altitude of 48 to 60 km. [Rocket Lab founder Peter] Beck has joined up with several noted planetary scientists, including Massachusetts Institute of Technology professor Sara Seager, to design this mission.

Electron will deliver the spacecraft into a 165 km orbit above Earth, where the rocket's high-energy Photon upper stage will perform a number of burns to raise the spacecraft's orbit and reach escape velocity. Assuming a May 2023 launch—there is a backup opportunity in January 2025—the spacecraft would reach Venus in October 2023. Once there, Photon would deploy a small, approximately 20 kg probe into the Venusian atmosphere.

The spacecraft will be tiny, as deep-space probes go, containing a 1 kg scientific payload consisting of an autofluorescing nephelometer, which is an instrument to detect suspended particles in the clouds. The goal is to search for organic chemicals in the clouds and explore their habitability. The probe will spend about 5 minutes and 30 seconds falling through the upper atmosphere, and then ideally continue transmitting data as it descends further toward the surface.

The CubeSat form factor small satellites have been very popular and have been funded by colleges, small companies and even NASA, who developed two that went to Mars along side the Mars InSight probe in 2018.  Despite that record, no company has ever privately developed and sent a spacecraft directly to another world in the Solar System beyond the Moon.  

Saying something is a high risk mission, by definition, means a high risk of failure.  Peter Beck seems to be saying, "nothing ventured, nothing gained, so why not try?" 

Rocket Lab's August 4th launch of the NRO payload - Rocket Lab photo.