Small Innovative Missions for Planetary Exploration (SIMPLEx) is a planetary exploration program operated by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

. The program funds small, low-cost spacecraft for stand-alone planetary exploration missions. These spacecraft are intended to launch as

secondary payload Secondary payload, also known as rideshare payload, is a smaller-sized payload transported to orbit on a launch vehicle that is mostly paid for—and with the date and time of launch and the orbital trajectory determined—by the entity that cont ...

s on other missions and are riskier than

Discovery Discovery may refer to: * Discovery (observation), observing or finding something unknown * Discovery (fiction), a character's learning something unknown * Discovery (law), a process in courts of law relating to evidence Discovery, The Discovery ...

or New Frontiers missions. The program selects missions from multiple proposals and gives them some money to begin development. After early development they are analyzed to see if they are cost-effective and scientifically valuable during Key Decision Point-C. If they pass Key Decision Point-C then they move into full development. The missions must weigh less than 180 kg. So far only the first two missions have launched, and the remaining missions have struggled to stay within budget and find missions to launch with, and have been removed from multiple launches.

Missions

On August 8, 2015, the first two SIMPLEx missions were selected: Q-PACE and LunaH-Map.NASA
Small Innovative Missions for Planetary Exploration Program Abstracts of selected proposals
August 8, 2015. Retrieved Nov. 17, 2022. They were both

CubeSat A CubeSat is a class of miniaturized satellite based around a form factor consisting of cubes. CubeSats have a mass of no more than per unit, and often use commercial off-the-shelf (COTS) components for their electronics and structure. CubeSats ...

s and each had a maximum budget of $5.6 million. Q-PACE launched on a

Virgin Orbit Virgin Orbit is a company within the Virgin Group which provides launch services for small satellites. On January 17, 2021, their ''LauncherOne'' rocket successfully reached orbit for the first time, and successfully deployed 10 cubesats. The ...

LauncherOne LauncherOne is a two-stage orbital launch vehicle developed and flown by Virgin Orbit that began operational flights in 2021, after being in development from 2007 to 2020. It is an air-launched rocket, designed to carry smallsat payloads of u ...

as part of the ELaNa 20 mission. LunaH-Map is a 6U CubeSat that will map

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

on the Moon. The mission launched as a secondary payload on Artemis-1. Three SIMPLEx-2 missions were selected in 2019. Janus was going to launch with

Psyche Psyche (''Psyché'' in French) is the Greek term for "soul" (ψυχή). Psyche may also refer to: Psychology * Psyche (psychology), the totality of the human mind, conscious and unconscious * ''Psyche'', an 1846 book about the unconscious by Car ...

and fly past multiple binary asteroid, but was removed from that mission due to the Psyche spacecraft being delayed. Lunar Trailblazer will launch with the IM-2 mission to study the Moon's geology and map its

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

. EscaPADE will send two small satellites to

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

to study its magnetosphere. So far, only two missions in the SIMPLEx program have launched.

Q-PACE

Q-PACE CubeSat Particle Aggregation and Collision Experiment (Q-PACE) or Cu-PACE, is an orbital spacecraft mission that would have studied the early stages of proto-planetary accretion by observing particle dynamical aggregation for several years.NAS ...

is a 3U CubeSat that would have studied the interactions of small particles in space in order to better understand early protoplanetary disks. The mission launched on January 17, 2021 on Virgin Orbit's

as part of NASA's ELaNa program. Contact was never established with the CubeSat.

LunaH-Map

LunaH-Map (Lunar Polar Hydrogen Mapper) is a 6U CubeSat that will map Hydrogen on the Moon using a neutron spectrometer. This mission launched as one of ten secondary payloads on Artemis 1. The mission was designed, built, and tested by

Arizona State University Arizona State University (Arizona State or ASU) is a public research university in the Phoenix metropolitan area. Founded in 1885 by the 13th Arizona Territorial Legislature, ASU is one of the largest public universities by enrollment in the ...

. It would have take over a year for LunaH-Map to reach its science orbit. After that, its 60 day science mission would begin. However, after it launched, the spacecraft ran into problems with its propulsion system. Janus spacecraft

Janus

Janus will send two small spacecraft to explore binary asteroids. The two spacecraft were scheduled to launch with

on a

Falcon Heavy Falcon Heavy is a partially reusable heavy-lift launch vehicle that is produced by SpaceX, an American aerospace manufacturer. The rocket consists of two strap-on boosters made from Falcon 9 first stages, a center core also made from a Falc ...

rocket. The two identical spacecraft (Janus A and B) are being built by Lockheed Martin and are powered by solar panels and rechargeable batteries. The original launch date for Psyche was August 1, 2022, but when that date was pushed to September 20, and then to 2023, NASA had to replan the trajectories for the Janus spacecraft. The Psyche launch was then moved to October 2023, but this new launch date will not allow Janus to complete its mission, so Janus was removed from the Psyche launch plan.

Lunar Trailblazer

Lunar Trailblazer will study water ice on the Moon and determine how it formed, how common it is, and where it is. The small spacecraft will be capable of looking inside permanently shadowed craters for water ice. The mission is managed by NASA's Jet Propulsion Laboratory. The spacecraft is scheduled to be completed in 2022 and will launch around the middle of 2023 as a secondary payload on

IM-2 ''Nova-C'' is a lunar lander designed by the private company Intuitive Machines to deliver small commercial payloads to the surface of the Moon. Intuitive Machines was one of nine contractor companies selected by NASA in November 2018 to sub ...

, Intuitive Machines' second lunar landing. The original plan was to launch Lunar Trailblazer as a secondary payload alongside IMAP in 2025, but since the spacecraft would have been ready years before it was scheduled to launch, NASA found an earlier launch opportunity.

EscaPADE

EscaPADE (Escape and Plasma Acceleration and Dynamics Explorers) will send two identical spacecraft to

. The spacecraft will be built by

Rocket Lab Rocket Lab is a public American aerospace manufacturer and launch service provider, with a New Zealand subsidiary. The company operates lightweight Electron orbital rockets, which provide dedicated launches for small satellites. Rocket Lab also ...

and will be based on its

Photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always ...

spacecraft bus. EscaPADE will study Mars' magnetosphere and how it has led to Mars' losing much of its atmosphere. The mission was originally going to launch with Janus and Psyche, but was removed from the Psyche launch manifest in 2020. On February 9, 2023, NASA announced that Blue Origin's

New Glenn New Glenn is a heavy-lift orbital launch vehicle in development by Blue Origin. Named after NASA astronaut John Glenn, design work on the vehicle began in 2012. Illustrations of the vehicle, and the high-level specifications, were initial ...

rocket would launch EscaPADE in late 2024. Eleven months after launch, EscaPADE will arrive at Mars. No other payloads were mentioned.

References

{{Planetary exploration NASA programs