Venus Life Finder

Venus Life Finder is a planned uncrewed spacecraft to Venus designed to detect signs of life in the Venusian atmosphere. The first private Venus mission, the spacecraft is being developed by Rocket Lab in collaboration with a team from the Massachusetts Institute of Technology. The spacecraft will consist of a Photon Explorer cruise stage which will send a small atmospheric probe into Venus with a single instrument, an autofluorescing nephelometer, to search for organic compounds within Venus' atmosphere.

Originally planned for launch in May 2023, the probe is now planned to launch no earlier than 30 December 2024, with arrival at Venus on 13 May 2025.

Mission goals
Research published in 2020 indicated the presence of phosphine (PH3) in Venus' atmosphere, resulting in a widespread public and academic interest in the possibility of life in the Venusian atmosphere. Although the probe will not directly search for phosphine, it will search for organic compounds in Venus' atmosphere, which would indicate potentially habitable conditions within Venus' cloud layer. Additionally, the mission will demonstrate an inexpensive, deep space mission with a small spacecraft and small launch vehicle, as well as mature the interplanetary Photon spacecraft. Peter Beck, CEO of Rocket Lab commented that the Venus Life Finder represents a "real opportunity in the market for these incremental little missions in between [NASA missions]".

Venus Life Finder is hoped to be the first of a series of small missions to Venus to better understand the planet.

Spacecraft design and instrumentation
The spacecraft consists of two main components- a Photon Explorer cruise stage, and a small atmospheric probe with a autofluorescing nephelometer.

The Explorer cruise stage, first developed for NASA's CAPSTONE, is the interplanetary variant of the Photon satellite bus. The Explorer cruise stage, a self contained spacecraft with solar arrays for generating power, an attitude control system and a HyperCurie engine for propulsion, will remain attached to the atmospheric probe until 30 minutes prior to atmospheric entry.

The 17 kg cone-shaped atmospheric probe measures just 40 cm across, which was chosen to accommodate the electronics and the focal length of the nephelometer. The probe outer mould line is a scaled-down version of the Deep Space 2 probe. Like the Deep Space 2 probe, the probe carries no parachute nor does it eject its heat shield. The nephelometer, flight computer, and radio are housed in a spherical titanium pressure vessel encased within a layer of insulation to protect the electronics and instrument from the corrosive Venusian atmosphere and maintain acceptable temperatures.

The probe contains one scientific instrument:
 * the Autofluorescence Nephelometer, which will project a 440 nm diode laser into the Venusian atmosphere through a fused silicate window. During the probe's descent, cloud particles which pass through the laser will scatter light, and if organic, these particles may also fluoresce. The scattered and fluoresced light will be collected through the same fused silicate window by a lens, from which the existence of organics, as well as particle size, shape, composition and concentration can be ascertained.

Venus Life Finder is being developed by a team of less than thirty people, led by Sara Seager of the Massachusetts Institute of Technology. The mission cost is estimate at less than 10 million US dollars, funded by Rocket Lab, MIT and undisclosed philanthropists. Peter Beck, CEO of Rocket Lab, has said that the spacecraft is a "nights-and-weekends project," and that it "gets pushed to the side all the time, but [they are] still working on it."

Mission profile
As of February 2024, Venus Life Finder is planned to launch no earlier than 30 December 2024 by an Electron launch vehicle from Rocket Lab's Launch Complex 1 on the Māhia Peninsula in New Zealand. After being delivered to low earth orbit, the Explorer cruise stage will perform a series of burns culminating in a lunar gravity assist which will send the spacecraft to Venus. During the 128 day interplanetary cruise, the spacecraft will make occasional mid-course corrections in preparation for arrival at Venus.

The probe will separate from the Explorer cruise stage 30 minutes before Venus atmospheric entry on 13 May 2025. Entering on the night-side to minimize background light for the autofluorescence nephelometer instrument, the probe will experience a peak g-force of 60 Gs and will descend through the atmosphere without a parachute. The probe will have just five minutes in the cloud layer, between 65 km to 45 km in altitude, to perform its measurements. The probe will directly transmit its data to Earth by S-band until expected loss of signal thirty minutes after atmospheric entry, after which it will impact the Venusian surface. Due to constraints on the power of the transmitter as well as limited transmission time, the data collected will be sent through a neural network to fit within the limited 125 bytes/second bandwidth allotted.