''Janus'' is a planned

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

mission that will send dual

space probe A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ...

s, ''Serenity'' and ''Mayhem'',https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=50260.0;attach=2070175;sess=0 to visit asteroids that will be chosen prior to launch date. The mission is part of NASA's SIMPLEx program and was expected to be launched in October 2023 as a secondary payload on

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 ...

together with the ''Psyche'' spacecraft, but it was removed due to an inability to reach its target from that launch date. On 3 September 2020, ''Janus'' successfully passed Key Decision Point-C and was approved for the final design of hardware. The mission budget is limited to US$55 million. Currently the new launch date and new launch vehicle is yet to be confirmed.

Spacecraft

The two small 36 kg spacecraft —which fall under the 180 kg mass limit for SIMPLEx missions — will conduct stand-alone planetary science missions. The spacecraft is jointly developed by two teams, based at the

University of Colorado Boulder The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a public research university in Boulder, Colorado. Founded in 1876, five months before Colorado became a state, it is the flagship university of the University of Colorado sy ...

(led by Daniel Scheeres) and at Lockheed Martin (led by Josh Wood). The two spacecraft, ''Janus'' A and B, also go by ''Serenity'' and ''Mayhem''.

Instruments

The ''Janus'' team plans to image the two asteroids in

visible Visibility, in meteorology, is a measure of the distance at which an object or light can be seen. Visibility may also refer to: * A measure of turbidity in water quality control * Interferometric visibility, which quantifies interference contrast ...

and

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

light, using the ECAM-M50 (visible) and ECAM-IR3a (infrared) cameras. These cameras were developed by

Malin Space Science Systems Malin Space Science Systems (MSSS) is a San Diego, California-based private technology company that designs, develops, and operates instruments and technical equipment to fly on unmanned spacecraft. MSSS is headed by chief scientist and CEO Mich ...

and successfully used on the

OSIRIS-REx OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid-study and sample-return mission. The mission's primary goal is to obtain a sample of at least from 101955 Bennu, a carbona ...

asteroid sample return mission.

Mission

Initial plan

In 2020, NASA gave approval for the ''Janus'' mission to proceed to the next phase of development. The mission is managed by the

Planetary Missions Program Office The Planetary Missions Program Office is a division of NASA headquartered at the Marshall Space Flight Center, formed by the agency's Science Mission Directorate (SMD). Succeeding the Discovery and New Frontiers Program Office, it was establ ...

at NASA's Marshall Space Flight Center in

Huntsville, Alabama Huntsville is a city in Madison County, Limestone County, and Morgan County, Alabama, United States. It is the county seat of Madison County. Located in the Appalachian region of northern Alabama, Huntsville is the most populous city in ...

, as part of the Solar System Exploration Program at NASA Headquarters in

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

The program conducts space science investigations in the Planetary Science Division of NASA's Science Mission Directorate at NASA Headquarters, guided by NASA's agency priorities and the Decadal Survey process of the National Academy of Sciences. ''Janus'' is led by the University of Colorado Boulder, where the

principal investigator In many countries, the term principal investigator (PI) refers to the holder of an independent grant and the lead researcher for the grant project, usually in the sciences, such as a laboratory study or a clinical trial. The phrase is also often us ...

(PI) is based, which will also undertake the scientific analysis for the mission. Lockheed Martin will manage, build and operate the spacecraft. After riding along with the launch of NASA's Psyche mission in October 2023, the ''Janus'' twins will separate and complete an orbit around the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

, before heading back toward

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

for a gravity assisted sling-shot, each going their separate ways to the two asteroids, and .

Delay and new targets

Because Psyche's launch date was moved from August 2022 to late September, new targets have to be chosen as ''Janus'' would be unable to visit the initially chosen asteroids and . Psyche's launch was again delayed on June 24, 2022, to an unspecified date after the end of 2022. It was removed from the Psyche mission on 18 November 2022, after an assessment determined that Janus would not be on the required trajectory to meet its science requirements as a result of Psyche’s new launch period.

References

External links

NSSDCA ''Janus'' Mission Page

New SIMPLEx Mission to Send SmallSats on Longest Deep Space Journey to Date
at

NASA's ''Janus'' Mission is Going to Visit Two Binary Asteroids
at Universe Today
Janus: A mission concept to explore two NEO Binary Asteroids
by D. J. Scheeres et at.
Where no spacecraft has gone before: A close encounter with binary asteroids
by Daniel Strain a
CU Boulder Today
{{Future spaceflights NASA space probes Lockheed Martin satellites and probes Missions to asteroids 2023 in spaceflight