Humans are sending messages into space all the time (albeit unwittingly in the form of radio waves), but the opportunity to deliberately send an actual physical message comes along pretty rarely.
So if you have ever wanted to become part of a NASA mission, now's your chance: the space agency will be sending social network communications from users on its round-trip mission to collect samples from the asteroid Bennu.
The Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer (OSIRIS-REx) spacecraft is due to launch in 2016, arriving at the 493-metre diameter asteroid in 2019 to spend 505 days mapping its surface and collecting samples before departing in 2021 to return to Earth in 2023.
The purpose for the mission is two-fold. Firstly, Bennu has been identified as a potential Earth impact; by conducting a close survey of the asteroid, including its exact shape and acceleration, and composition, NASA researchers will better be able to predict the likelihood of such an event.
Secondly, NASA hopes to study the composition of the asteroid -- formed from the leftover dust and gas of the nebula that collapsed to form the sun -- as a means of studying the conditions of the formation of the solar system.
"This asteroid is a time capsule from the birth of our solar system and ushers in a new era of planetary exploration," said NASA Planetary Science Division Director Jim Green, when announcing the mission in 2011.
So sending a time capsule aboard the OSIRIS-REx seems apropos.
Members of the public are invited to hashtag Tweets and Instagram photos with #AsteroidMission for consideration for the time capsule. But NASA won't just be sending any old messages: participants are asked to think about the current state of the exploration of our solar system and predict how we might be communicating and where we will be in the solar system in 2023.
The mission team will then choose the 50 best Tweets and the 50 best images to be placed in the capsule, alongside the microchip that will carry the names of space enthusiasts on the mission.
"Our progress in space exploration has been nothing short of amazing," said OSIRIS-REx principal investigator at the University of Arizona, Tucson Dante Lauretta. "I look forward to the public taking their best guess at what the next 10 years holds and then comparing their predictions with actual missions in development in 2023."
Submissions close on September 30, 2014. You can find more detailed submission guidelines on the official Asteroid Time Capsule website.